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1 pages, 186 KiB

Open AccessAbstract

Electrocatalytical Chemical Sensor for Hydrogen Peroxide

by Arwa Laroussi, Noureddine Raouafi and Vladimir Mirsky

Eng. Proc. 2021, 6(1), 1; https://doi.org/10.3390/I3S2021Dresden-10168 - 21 May 2021

Viewed by 749

Abstract

The fast and selective determination of hydrogen peroxide (H₂O₂) is of importance not only because of strong interest in this widely applied analyte, but also because of the development of enzymatic biosensors for glucose or other metabolites where the [...] Read more.

The fast and selective determination of hydrogen peroxide (H₂O₂) is of importance not only because of strong interest in this widely applied analyte, but also because of the development of enzymatic biosensors for glucose or other metabolites where the sensor for H₂O₂ can be used as the transducer. Here, we report on an electrocatalytical amperometric sensor for the detection of H₂O₂. It is a sensor that consists of a gold electrode covered by a self-assembled monolayer (SAM) with immobilized p-benzoquinone. To provide highly stable immobilization of p-benzoquinone at the distance of effective electron tunneling, a new anchor compound—1,3-dimercaptopropan-2-ol—was synthesized and used for preparation of the SAM. Due to two thiol groups binding gold surface, this compound provides high stability of the SAM. The surface concentration of p-benzoquinone obtained from cyclic voltammetry is 2.5 ± 0.2 × 10⁻¹⁰ mol·cm⁻². Cyclic voltammetry and chronoamperometry experiments proved that the immobilized benzoquinone exhibited high electrocatalytic activity towards the decomposition of H₂O₂. Depending on the used potential range, different sensing modes can be realized. For example, one can measure electrochemical response due to the oxidation of H₂O₂ at anodic potentials, or due to the reduction of oxygen formed during oxidative decomposition of H₂O₂. Also, amperometric response at fixed potential of +0.4 V vs. Ag/AgCl corresponding to the oxidation of benzoquinone to hydroquinone was studied. The sensor exhibited a linear response over a concentration range of 0.1–2 mM with a low detection limit of 4.24 µM. The reproducibility of three different electrodes prepared was examined at the H₂O₂ concentration range from 0.1 till 3 mM, which resulted in a relative standard deviation below 4.2%. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 151 KiB

Open AccessAbstract

Sensing of Nickel(II) Ions by Immobilizing Ligands and Using Different SPEs

by Liliana Anchidin-Norocel, Sonia Amariei and Gheorghe Gutt

Eng. Proc. 2021, 6(1), 2; https://doi.org/10.3390/I3S2021Dresden-10106 - 17 May 2021

Viewed by 832

Abstract

The aim of this paper is the development of a sensor for the quantification of nickel ions in food raw materials and foods. It is believed that about 15% of the human population suffers from nickel allergy. In addition to digestive manifestations, food [...] Read more.

The aim of this paper is the development of a sensor for the quantification of nickel ions in food raw materials and foods. It is believed that about 15% of the human population suffers from nickel allergy. In addition to digestive manifestations, food intolerance to nickel may also have systemic manifestations, such as diffuse dermatitis, diffuse itching, fever, rhinitis, headache, altered general condition. Therefore, it is necessary to control this content of nickel ions for the health of the human population by developing a new method that offers the advantages of a fast, not expensive, in situ, and accurate analysis. For this purpose, bismuth oxide-screen-printed electrodes (SPEs) and graphene-modified SPEs were used with a very small amount of dimethylglyoxime and amino acid L-histidine that were deposited. A potentiostat that displays the response in the form of a cyclic voltammogram was used to study the electrochemical properties of nickel standard solution with different concentrations. The results were compared and the most sensitive sensor proved to be bismuth oxide-SPEs with dimethylglyoxime (Bi₂O₃/C-dmgH₂) with a linear response over a wide range (0.1–10 ppm) of nickel concentrations. Furthermore, the sensor shows excellent selectivity in the presence of common interfering species. The Bi₂O₃/C-dmgH₂ sensor showed good viability for nickel analysis in food samples (cocoa, spinach, cabbage, and red wine) and demonstrated significant advancement in sensor technology for practical applications. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 149 KiB

Open AccessAbstract

Electrical Control of the Receptor Affinity

by Yulia Efremenko and Vladimir M. Mirsky

Eng. Proc. 2021, 6(1), 3; https://doi.org/10.3390/I3S2021Dresden-10084 - 17 May 2021

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Abstract

A concept of virtual sensor array based on an electrically controlled variation of affinity properties of the receptor layer was realized on the base of integrated electrochemical chemotransistor containing conducting polymer as the receptor layer. Electrical control of the redox-state of the polymer [...] Read more.

A concept of virtual sensor array based on an electrically controlled variation of affinity properties of the receptor layer was realized on the base of integrated electrochemical chemotransistor containing conducting polymer as the receptor layer. Electrical control of the redox-state of the polymer (polyaniline) was performed in a five-electrode configuration with four electrodes for conductivity measurements and Ag/AgCl reference electrode integrated on the same glass chip. An ionic liquid provided an electrical connection between the reference electrode and chemosensitive material. Conductivity measurements demonstrated potential controlled electrochemical conversions of the receptor material between different redox states. The binding of trimethylamine at three different potentials corresponding to these states was studied. The results demonstrated that both kinetic- and equilibrium-binding properties of the receptor are controlled by the electrical potential, thus providing a possibility to form a virtual sensor array using only a single sensing element. The concept was applied for monitoring fish headspace. Using three characteristics of the sensor response measured at three different redox states of the same sensor material, we obtained signals from a virtual sensor array consisting of nine chemosensitive elements. The sensor displays systematic changes of its nine signals during fish degradation. This approach can be applied also for the electrical control of the affinity of immunoglobulins. Development of new materials with electrically controlled affinity is in progress. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 161 KiB

Open AccessAbstract

Ultra-Wideband Localization of Pulmonary Nodules during Thoracoscopic Surgery

by Alberto Battistel and Knut Möller

Eng. Proc. 2021, 6(1), 4; https://doi.org/10.3390/I3S2021Dresden-10095 - 17 May 2021

Cited by 1 | Viewed by 674

Abstract

Lung cancer is one of the most common causes of cancer-related death worldwide. It is usually detected by CT or MRI and removed through thoracoscopic surgery. However, during surgery, the lung collapses, and a new determination of the position of the pulmonary nodule [...] Read more.

Lung cancer is one of the most common causes of cancer-related death worldwide. It is usually detected by CT or MRI and removed through thoracoscopic surgery. However, during surgery, the lung collapses, and a new determination of the position of the pulmonary nodule is necessary, which is particularly challenging in the case of minimally invasive surgeries when palpation is not possible. In this contribution, ultra-wideband (UWB) radio technology, which employs a short burst of high-frequency electromagnetic waves, is studied to localize the pulmonary nodule. In short, an antenna in close proximity with the lung surface produces a signal, and the echo emanating from discontinuities in the lung tissue, i.e., the pulmonary nodule, can be used for the localization. A similar approach has already been proposed for breast cancer. Simulations were used to explore the relationship between frequency range and penetration depth and showed that shallow nodules, below 2 cm in depth, are difficult to resolve because the echo directly interferes with the propagating signal. On the other hand, given the strong electromagnetic attenuation of lung tissue, echo emanating from near organs is suppressed, and frequency-band tuning can be employed to range the depth of the investigation. Ultimately, this contribution shows how to employ and design UWB technology to localize deep pulmonary nodules through a minimally invasive approach. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 174 KiB

Open AccessAbstract

Tungsten Oxide Based Hydrogen Gas Sensor Prepared by Advanced Magnetron Sputtering

by Nirmal Kumar, Stanislav Haviar, Jiří Rezek, Jiří Čapek and Pavel Baroch

Eng. Proc. 2021, 6(1), 5; https://doi.org/10.3390/I3S2021Dresden-10154 - 18 May 2021

Viewed by 663

Abstract

In this study, we demonstrate the advantages of two advanced sputtering techniques for the preparation of a thin-film conductometric gas sensor. We combined tungsten oxide (WO₃) thin films with other materials to achieve enhanced sensorial behavior towards hydrogen. Thin films of [...] Read more.

In this study, we demonstrate the advantages of two advanced sputtering techniques for the preparation of a thin-film conductometric gas sensor. We combined tungsten oxide (WO₃) thin films with other materials to achieve enhanced sensorial behavior towards hydrogen. Thin films of WO₃ were prepared using the DC and HiPIMS technique, which allowed us to tune the phase composition and crystallinity of the oxide by changing the deposition parameters. The second material was then added on-top of these films. We used the copper tungstate CuWO₄ in the form of nano-islands deposited by reactive rf sputtering and Pd particles formed during conventional dc sputtering. The specimens were tested for their response to a time-varied hydrogen concentration in synthetic air at various temperatures. The sensitivity and response time were evaluated. The performance of the individual films is presented as well as the details of the synthesis. Advanced magnetron techniques (such as HiPIMS) allowed us to tune the property of the film to improve its sensorial behavior. The method is compatible with the silicon electronics industry and consists of a few steps that do not require any wet technique, and the films can be used in an as-deposited state. Therefore, sensorial nanostructured materials prepared using magnetron sputtering are very suitable for use in miniaturized electronic devices. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 169 KiB

Open AccessAbstract

Flexible SERS Sensors Based on Carbon Nanomaterials-Supported Au Nanostructures

by Rong Yang, Weichen Fang, Xiao Zuo, Igor M. De Rosa and Wenbo Xin

Eng. Proc. 2021, 6(1), 7; https://doi.org/10.3390/I3S2021Dresden-10075 - 17 May 2021

Viewed by 785

Abstract

Surface-enhanced Raman scattering (SERS) is a powerful technique to detect analytes in a label-free and non-destructive way at extremely low concentrations, even down to the single-molecule level. In the present study, a series of anisotropic Au nanostructures are integrated onto the platforms of [...] Read more.

Surface-enhanced Raman scattering (SERS) is a powerful technique to detect analytes in a label-free and non-destructive way at extremely low concentrations, even down to the single-molecule level. In the present study, a series of anisotropic Au nanostructures are integrated onto the platforms of carbon nanomaterials, mainly including carbon nanotubes (CNTs) and graphene, in order to fabricate high-performance flexible SERS sensors. Sizes, dimensions, and shapes of Au nanostructures can be well controlled through this strategy, based on which Au nanowires, nanoribbons, nanoplates, nanobelts, and nanoframes are successfully deposited onto CNT films and graphene templates, respectively. Significantly enhanced plasmonic activity originates from these Au nanocrystals, which provide increased SERS signals of the analytes by many orders of magnitude, while CNT films or graphene substrates offer superior flexibility and accessibility. For instance, A flexible SERS sensor made of graphene supported Au nanoframes can detect the analyte R6G at the concentration as low as 10⁻⁹ M. The mechanism for the sensitivity enhancement could be attributed to the homogenous distribution of Au nanoframes on the graphene support as well as the strong molecule adsorption to the graphene nanoporous network. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 148 KiB

Open AccessAbstract

Compliant Magnetic Field Sensor Technologies

by Denys Makarov

Eng. Proc. 2021, 6(1), 8; https://doi.org/10.3390/I3S2021Dresden-10066 - 17 May 2021

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Abstract

We review the recent progress in the field of shapeable magnetoelectronics allowing the realization of mechanically imperceptible electronic skins, which enable perception of the geomagnetic field (e-skin compasses), featuring sensitivities down to ultra-small fields of sub-50 nT. We demonstrate that e-skin compasses allow [...] Read more.

We review the recent progress in the field of shapeable magnetoelectronics allowing the realization of mechanically imperceptible electronic skins, which enable perception of the geomagnetic field (e-skin compasses), featuring sensitivities down to ultra-small fields of sub-50 nT. We demonstrate that e-skin compasses allow humans to orient with respect to Earth’s magnetic field ubiquitously. The biomagnetic orientation enables novel interactive devices for virtual and augmented reality applications, which is showcased by realizing touchless control of virtual units in a game engine using omnidirectional magnetosensitive skins. This concept is further extended by demonstrating a compliant magnetic microelectromechanical platform (m-MEMS), which is able to transduce both tactile (via mechanical pressure) and touchless (via magnetic field) stimulations simultaneously and discriminate them in real time. These devices are crucial for interactive electronics and human–machine interfaces, but also for the realization of smart soft robotics with highly compliant integrated feedback systems including in medicine for physicians and surgeons. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 176 KiB

Open AccessAbstract

A High-Resolution Fully Inkjet Printed Resonant Mass Sensor

by Bruno Andò, Salvatore Baglio, Ruben Crispino and Vincenzo Marletta

Eng. Proc. 2021, 6(1), 9; https://doi.org/10.3390/I3S2021Dresden-10087 - 12 May 2021

Viewed by 564

Abstract

The rapid prototyping of low-cost sensors is assuming strategic importance in several application fields. In this paper, a fully inkjet printed mass sensor is proposed. The device consists of a poly-ethylene terephthalate (PET) cantilever beam, which is driven to its resonant mode by [...] Read more.

The rapid prototyping of low-cost sensors is assuming strategic importance in several application fields. In this paper, a fully inkjet printed mass sensor is proposed. The device consists of a poly-ethylene terephthalate (PET) cantilever beam, which is driven to its resonant mode by an electromagnetic actuation mechanism, implemented through the interaction between a current impulse flowing through a planar coil (inkjet printed on the PET beam), and a permanent magnet, facing the actuation coil. Target masses are positioned close to the beam end. The sensing methodology, based on the relationship between the beam first natural frequency and the target mass, is implemented through a strain gauge (inkjet printed across the fixed end of the cantilever). The resonant operating mode of the sensor confers intrinsic robustness against instabilities of the strain sensor structure (e.g., the residual stress of the cantilever beam), the target mass material and the magnet–coil distance. The latter indeed changes as a function of the target mass values. The friction-less actuation mode is another shortcoming of the sensor, as well as the low-cost feature arising from the adopted technology. As far as we know, the solution proposed is the first example of a low-cost fully printed mass sensor. The operating range of the device is 0–0.36 g while its resolution is in the order of 1.0 mg, thus addressing crucial application fields. A Q factor around 35 has been estimated, which confirms the suitable performances of the sensor in term of selectivity and resolution. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 163 KiB

Open AccessAbstract

ZnO Low-Dimensional Thin Films Used as a Potential Material for Water Treatment

by Anna Kulis-Kapuscinska, Monika Kwoka, Michal Adam Borysiewicz, Massimo Sgarzi and Gianaurelio Cuniberti

Eng. Proc. 2021, 6(1), 10; https://doi.org/10.3390/I3S2021Dresden-10131 - 17 May 2021

Viewed by 803

Abstract

In this work, the properties of zinc oxide (ZnO) low-dimensional conductive oxide nanostructures in the aspect of their potential applications in microelectronics, in toxic gas sensing, as well as in water remediation, have been determined. ZnO nanostructured porous thin films deposited by DC [...] Read more.

In this work, the properties of zinc oxide (ZnO) low-dimensional conductive oxide nanostructures in the aspect of their potential applications in microelectronics, in toxic gas sensing, as well as in water remediation, have been determined. ZnO nanostructured porous thin films deposited by DC reactive sputtering (RS) have been deposited on Si substrates at different temperature conditions. For surface properties and chemical morphology analysis, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) have been used. Thanks to these techniques, it was possible to obtain information on thin film surface modifications caused by the adsorption of atmospheric carbon dioxide, and by the adsorption of photodegradation products following the photocatalysis experiments. The ZnO thin films were tested for their photocatalytic properties under UV light irradiation. For this purpose, methylene blue was used as a dye model pollutant to evaluate the activity of the nanostructures. It was observed that the ZnO thin films are able to photocatalytically degrade methylene blue. These results demonstrate that properly selected zinc oxide nanostructures, currently used in toxic gas sensing, can find application in the removal of micropollutants such as dyes and pharmaceuticals present in wastewater. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

2 pages, 192 KiB

Open AccessAbstract

Chitosan-Based Piezoelectric Flexible and Wearable Patch for Sensing Physiological Strain

by Gaia de Marzo, Denis Desmaële, Luciana Algieri, Lara Natta, Francesco Guido, Vincenzo Mastronardi, Massimo Mariello, Maria Teresa Todaro, Francesco Rizzi and Massimo De Vittorio

Eng. Proc. 2021, 6(1), 12; https://doi.org/10.3390/I3S2021Dresden-10124 - 17 May 2021

Cited by 3 | Viewed by 1383

Abstract

Innovative biocompatible organic materials with piezoelectric properties have great potential for the development of wearable sensors for monitoring physiological parameters. Among them, Chitosan (CS) is a natural, biodegradable, antibacterial and low cost biopolymer that shows interesting piezoelectric behaviour. In this context, this work [...] Read more.

Innovative biocompatible organic materials with piezoelectric properties have great potential for the development of wearable sensors for monitoring physiological parameters. Among them, Chitosan (CS) is a natural, biodegradable, antibacterial and low cost biopolymer that shows interesting piezoelectric behaviour. In this context, this work reports on a protocol where plain chitosan films (CS-F) are exploited to easily create a flexible, wearable piezoelectric patch. By adapting a previously reported simple drop casting method, we here demonstrate that a 70 μm thick CS-F can exhibit good piezoelectric properties. The structure of CS-F was analysed via the XRD technique: the spectrum reveals peaks of partially crystalline chitosan film, indicating the presence of organized polymeric chains (Suppl. Ppt. Slide 8). Piezoresponse Force Microscopy scans confirmed the presence of domains with opposite polarization directions with an extrapolated value of the piezoelectric coefficient d₃₃ of 2.54 pC/N. A microfabrication process for patch realization has been set up. The top electrode was created by the simple thermal evaporation of gold directly onto the free-standing CS-F (Suppl. Ppt. Slide 10). This bilayer was then precisely cut using a cutting plotter and assembled on the copper bottom electrode (Suppl. Ppt. Slide 11). The complete patch can be conformally applied on the skin. The ability of the device to sense physiological movements was validated by an ad hoc measurement set up generating strain pulses; open circuit voltage peaks up to 20 mV were detected (Suppl. Ppt. Slide 13). This sensor represents an important step towards totally biocompatible and biodegradable wearable devices. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 164 KiB

Open AccessAbstract

Supramolecular Functionalized Pristine Graphene Utilizing a Bio-Compatible Stabilizer towards Ultra-Sensitive Ammonia Detection

by Shirong Huang, Luis Antonio Panes-Ruiz, Alexander Croy, Leif Riemenschneider, Vyacheslav Khavrus, Viktor Bezugly and Gianaurelio Cuniberti

Eng. Proc. 2021, 6(1), 14; https://doi.org/10.3390/I3S2021Dresden-10089 - 17 May 2021

Viewed by 809

Abstract

Recently, graphene has attracted intensive attention in the gas sensing field due to its high electrical conductivity as well as large specific surface areas. Lots of graphene-based gas sensors have been reported with excellent gas sensing performance. However, the sensing element materials for [...] Read more.

Recently, graphene has attracted intensive attention in the gas sensing field due to its high electrical conductivity as well as large specific surface areas. Lots of graphene-based gas sensors have been reported with excellent gas sensing performance. However, the sensing element materials for most of the above sensors actually consist of a reduced graphene oxide (rGO) derivative rather than pristine graphene, such as rGO, rGO/metal particle, rGO/polymers, etc. Complex chemical oxidation and reduction are usually involved for the preparation of reduced graphene oxide derivatives. Even though there are some pristine graphene-based gas sensors synthesizing with the approaches of chemical vapor deposition (CVD) or mechanical cleavage, the high cost of the set-up or the low productivity cannot decrease the cost of the practical sensors. In this work, we develop pristine graphene-based gas sensors utilizing flavin monocleotide sodium salt (FMNS) toward ultra-sensitive ammonia detection. The sensor has 3% response upon exposure to 10 ppm NH₃ and a limit of detection of 1.6 ppm at room temperature and shows a good recovery. Raman, UV–Vis, FT-IR spectra, as well as scanning electron microscope (SEM) measurements are employed to characterize the quality of the graphene flakes, indicating a good structural quality of graphene with few defects. The effects of the concentration of graphene dispersion functionalized by FMNS on the sensing performance towards ammonia sensing were also investigated. The process is very mild, environmentally friendly, and low cost. We believe this work may pave a path to design a high-performance gas sensor with low cost and boost the application of graphene for sensing. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 164 KiB

Open AccessAbstract

Detection of C-Reactive Protein by Liquid-Gated Carbon Nanotube Field Effect Transistors (LG-CNTFET): A Promising Tool against Antibiotic Resistance

by Luis Antonio Panes-Ruiz, Tom Stückemann, Leif Riemenschneider, Markus Löffler, Viktor Bezugly and Gianaurelio Cuniberti

Eng. Proc. 2021, 6(1), 15; https://doi.org/10.3390/I3S2021Dresden-10114 - 17 May 2021

Viewed by 891

Abstract

Respiratory tract infections have the highest rates of antibiotic prescriptions where symptoms like fever, cough, and rigors are regularly misinterpreted and where bacterial infections cannot be distinguished from viral ones. Nevertheless, it has been recently suggested that C-reactive protein (CRP), a protein produced [...] Read more.

Respiratory tract infections have the highest rates of antibiotic prescriptions where symptoms like fever, cough, and rigors are regularly misinterpreted and where bacterial infections cannot be distinguished from viral ones. Nevertheless, it has been recently suggested that C-reactive protein (CRP), a protein produced by the liver in response to infection, could serve as a potential biomarker for the precise differentiation of these two types of infections. Thus, its quick and accurate detection would potentially reduce the unnecessary antibiotic use. To this end, we present an easy and sensitive approach for the selective detection of C-reactive protein (CRP) by liquid-gated carbon nanotube field effect transistors (LG-CNTFET). Herein, CNT-networks were deposited between electrodes via controlled dielectrophoretic deposition and then functionalized with a novel specific antibody and a polyethylene glycol (PEG) layer in order to overcome the Debye screening. The successful fabrication and functionalization were confirmed by scanning electron microscopy. The results showed a selective and reproducible detection down to picomolar concentrations in PBS buffer without complicated microfluidics. The simplicity and high sensitivity of this sensor platform make it a promising tool for the quick and precise differential diagnosis of viral and bacterial infections. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 169 KiB

Open AccessAbstract

CuO-Doped Alginate for Simple Electrochemical Vitamin C Sensing in Sweat

by Bergoi Ibarlucea, Arnau Perez Roig, Dmitry Belyaev, Larysa Baraban and Gianaurelio Cuniberti

Eng. Proc. 2021, 6(1), 16; https://doi.org/10.3390/I3S2021Dresden-10090 - 17 May 2021

Viewed by 698

Abstract

Heat-exposed work activities or prolonged sport sessions suppose a continuous nutrient loss through sweating, leading to long-term health issues. Among prevention steps, the use of miniaturized sensors for real-time monitoring of micronutrient presence directly in sweat can be of great interest. Here, we [...] Read more.

Heat-exposed work activities or prolonged sport sessions suppose a continuous nutrient loss through sweating, leading to long-term health issues. Among prevention steps, the use of miniaturized sensors for real-time monitoring of micronutrient presence directly in sweat can be of great interest. Here, we propose a flexible sensor for the detection of vitamin C (ascorbic acid) based on a very simple process of electrode modification via electrodeposition of a membrane containing CuO nanoparticles. The reductive effect of ascorbic acid on the nanoparticles produces a shift of the redox peaks in cyclic voltammetry analysis, which can be measured at nearly zero volts as a current increase by amperometry. The detection is performed efficiently at the micromolar ascorbic acid levels found naturally in sweat and works at ultra-low potential (−5 mV), showing no interferences with other typical molecules found in the samples. In combination with sensors for other nutrients, this can be a promising approach for preventive healthcare applications. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 186 KiB

Open AccessAbstract

Self-Assembled Monolayers from Symmetrical Di-Thiols: Preparation, Characterization and Application for the Assembly of Electrochemically Active Films

by Arwa Laroussi, Małgorzata Kot, Jan Ingo Flege, Noureddine Raouafi and Vladimir Mirsky

Eng. Proc. 2021, 6(1), 17; https://doi.org/10.3390/I3S2021Dresden-10112 - 17 May 2021

Viewed by 720

Abstract

1,3-dimercaptopropan-2-ol, a symmetrical di-thiol, has been synthesized and applied as a new type of anchor molecule to prepare a self-assembled monolayer (SAM) on a gold surface. The formed monolayers were studied by cyclic voltammetry, impedance spectroscopy, X-ray photoelectron spectroscopy, kinetic capacitance, and contact [...] Read more.

1,3-dimercaptopropan-2-ol, a symmetrical di-thiol, has been synthesized and applied as a new type of anchor molecule to prepare a self-assembled monolayer (SAM) on a gold surface. The formed monolayers were studied by cyclic voltammetry, impedance spectroscopy, X-ray photoelectron spectroscopy, kinetic capacitance, and contact angle measurements. The SAM structure depends on the adsorption conditions. A short incubation time of the electrode at high concentration of this di-thiol leads to the predominating binding through one thiol group of the adsorbate to the gold surface, while a long incubation at low concentration leads to the predominating binding by both thiol groups. A comparative study of the desorption and replacement of SAMs indicates a strong stability increase when the SAM molecules bond gold surfaces by two bonds mainly. This monolayer was used to immobilize electrochemically active p-benzoquinone moiety. The surface concentration of p-benzoquinone obtained from cyclic voltammetry is 2.5 ± 0.2 × 10⁻¹⁰ mol cm⁻², which corresponds to the functionalization of 65 ± 5% of SAM molecules. The obtained highly stable SAM with redox-active terminal group can be applied for different tasks of chemical sensing and biosensing. As an example, an application of this system for electrocatalytical oxidation of dihydronicotinamide adenosine dinucleotide (NADH) was tested. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 164 KiB

Open AccessAbstract

Hemocompatible Electrochemical Sensors for Continuous Monitoring of Blood Parameters

by Sascha Balakin, Bergoi Ibarlucea, Dmitry Belyaev, Larysa Baraban, Stefanie Hänsel, Manfred Maitz, Carsten Werner and Gianaurelio Cuniberti

Eng. Proc. 2021, 6(1), 19; https://doi.org/10.3390/I3S2021Dresden-10174 - 21 May 2021

Cited by 1 | Viewed by 871

Abstract

The real-time monitoring of physiological parameters is essential for point-of-care testing. While nowadays routine tests are done through ex vivo analysis on frequently extracted blood, placing implantable sensors monitoring key blood parameters such as lactate, glucose, ions, and oxygen would mean a giant [...] Read more.

The real-time monitoring of physiological parameters is essential for point-of-care testing. While nowadays routine tests are done through ex vivo analysis on frequently extracted blood, placing implantable sensors monitoring key blood parameters such as lactate, glucose, ions, and oxygen would mean a giant step forward in the care of critically ill patients, improving the response time in emergencies and diminishing the invasiveness of the measurements. The recent advances in microelectronics and nanotechnology are a promising technology enabling moving in that direction. The goal of our work is to develop arrays of electrochemical sensors with selective and hemocompatible coatings, allowing for the future implementation of such measurements in patients. We perform the analysis of blood parameters in a label-free and electrochemical manner which is compatible with the inevitable miniaturization in a real application. The tuneable composition of the layer will allow to pursue further applications in the future by modification of the receptor molecules and their concentrations. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 177 KiB

Open AccessAbstract

Highly Sensitive Silicon Nanowire Biosensor Devices for the Investigation of UniCAR Platform in Immunotherapy

by Trang-Anh Nguyen-Le, Diana Isabel Sandoval Bojorquez, Arnau Pérez Roig, Bergoi Ibarlucea, Gianaurelio Cuniberti, Anja Feldmann, Michael Bachmann and Larysa Baraban

Eng. Proc. 2021, 6(1), 20; https://doi.org/10.3390/I3S2021Dresden-10109 - 17 May 2021

Viewed by 866

Abstract

Although showing impressive therapeutic potential, treatments of leukemias with T-cells expressing chimeric antigen receptors (CARs) is limited by their risk of several severe side effects. To overcome these problems, a switchable CAR platform has been developed termed UniCAR. Unlike conventional CAR, which is [...] Read more.

Although showing impressive therapeutic potential, treatments of leukemias with T-cells expressing chimeric antigen receptors (CARs) is limited by their risk of several severe side effects. To overcome these problems, a switchable CAR platform has been developed termed UniCAR. Unlike conventional CAR, which is directed against tumor-associated antigens, UniCAR treatment involves an intermediate target module (TM), which can cross-link UniCAR T cells with tumor cells and lead to destruction. The development of these novel TMs against different tumor targets requires numerous repetitive tests on different synthesizing trials, which is usually limited in quantity and time-consuming. Meanwhile, nano-biosensors are lately known as analytical tools, which are highly sensitive, label-free, rapid and reagent-saving. Among them, silicon nanowire (SiNW) sensors have been extensively investigated by researchers over the past decades thanks to their compatibility with CMOS technology, enabling mass production. In this work, we demonstrated the application of a previously published SiNW biosensor on the detection of the binding of UniCAR and a part of different TMs. The results underline the advantages of the SiNW sensor over the ELISA method in terms of ease of preparation, speed and sensitivity. The method is able to evaluate the binding affinity of UniCAR to different TMs and open a potential to quantify the number of active UniCAR T-cells in an in vivo sample at a later stage. In the end, the application of a nanosensor may speed up the R&D process of the UniCAR concept and later play an important role in clinical monitoring of immunotherapy, especially in the era of precision medicine. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 179 KiB

Open AccessAbstract

Fluorescent Carbon Nanodots as Sensors of Toxic Metal Ions and Pesticides

by Federico Bruno, Alice Sciortino, Gianpiero Buscarino, Marco Cannas, Franco Mario Gelardi, Simonpietro Agnello and Fabrizio Messina

Eng. Proc. 2021, 6(1), 21; https://doi.org/10.3390/I3S2021Dresden-10096 - 17 May 2021

Cited by 1 | Viewed by 667

Abstract

Carbon nanodots (CDs) are a new class of fluorescent carbon-based nanomaterials characterized by a plethora of morphologies and sizes. Among these, we can include two different types of CDs, namely, graphitic and diamond-like. This wide range of structures opens up the possibility to [...] Read more.

Carbon nanodots (CDs) are a new class of fluorescent carbon-based nanomaterials characterized by a plethora of morphologies and sizes. Among these, we can include two different types of CDs, namely, graphitic and diamond-like. This wide range of structures opens up the possibility to design different CDs, with tunable optical properties accordingly to the synthesis method and precursors used. We prepared two different CDs following a bottom-up approach by thermally induced decomposition of organic precursors (namely, citric acid and urea in different molar ratios), and using purification by Size Exclusion Chromatography (SEC). Obtained CDs were characterized by Raman, absorption and fluorescence (PL) spectroscopies to understand structural and optical properties, and by atomic force microscopy (AFM) to elucidate morphology. They feature graphitic and diamond-like carbon structures with highly efficient visible emissions. Their sensing towards Cd and Hg heavy metals has been tested by PL experiments. We found a PL quenching in the presence of concentrations of metal salts starting from 0.5 μM and a selectivity towards the interacting ions, depending on the CDs structure, enabling using them for sensing. Furthermore, preliminary experiments suggest that these dots can also be used in principle as sensors of common pesticides. Considering the advantages of carbon dots with respect to other nanomaterials, such as non-toxicity, low cost and ease of synthesis, we consider these results to be very promising in view of exploiting the optical response of carbon dots to fabricate in the near future a variety of pollutant-sensing devices. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 177 KiB

Open AccessAbstract

Strain Sensor Based on Biological Nanomaterial

by Levan P. Ichkitidze, Alexander Yu. Gerasimenko, Dmitry V. Telyshev, Eugeny P. Kitsyuk, Vladimir A. Petukhov and Sergei V. Selishchev

Eng. Proc. 2021, 6(1), 23; https://doi.org/10.3390/I3S2021Dresden-10115 - 17 May 2021

Viewed by 642

Abstract

We investigated a prototype of a strain sensor based on the layers of a bionanomaterial containing bovine serum albumin (BSA matrix) and multi-walled carbon nanotubes (MWCNT filler). The aqueous dispersion of 25 wt.% BSA/0.3 wt.% MWCNT was applied by screen printing onto flexible [...] Read more.

We investigated a prototype of a strain sensor based on the layers of a bionanomaterial containing bovine serum albumin (BSA matrix) and multi-walled carbon nanotubes (MWCNT filler). The aqueous dispersion of 25 wt.% BSA/0.3 wt.% MWCNT was applied by screen printing onto flexible polyethylene terephthalate substrates. After drying the layers by laser irradiation (~970 nm), various parameters of the layers were controlled, i.e., resistance R, bending angle θ, number of cycles n, and measurement time. One measurement cycle corresponded to a change within the range θ = ±150°. The layers of the BSA/MWCNT bionanomaterial had dimensions of (15 ÷ 20) mm × (8 ÷ 10) mm × (0.5 ÷ 1. 5) µm. The dependences of resistance R on the bending angle θ were similar for all layers at θ = ±30, and the R(θ) curves represented approximate linear dependences (with an error of ≤ 10%); beyond this range, the dependences became nonlinear. The following quantitative values were obtained for the investigated strain sensor: specific conductivity ~1 ÷ 10 S/m, linear strain sensitivity ~160, and bending sensitivity 1.0 ÷ 1.5%/°. These results are high. The examined layers of the bionanomaterial BSA/MWCNT as a strain sensor are of particular interest for medical practice. In particular, strain sensors can be implemented by applying a water dispersion of nanomaterials to human skin using a 3D printer for monitoring movements (arms and blinking) and the detection of signs of pathology (dysphagia, respiratory diseases, angina, etc.). Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 162 KiB

Open AccessAbstract

Impedance Characterization of Particles One by One Using a Nanosensor Electronic Platform

by Diana Isabel Sandoval Bojorquez, Eduardo Sergio Oliveros Mata, Julian Schütt, Michael Bachmann and Larysa Baraban

Eng. Proc. 2021, 6(1), 24; https://doi.org/10.3390/I3S2021Dresden-10110 - 17 May 2021

Viewed by 694

Abstract

Impedance cytometry represents a technique that allows the electronic characterization of colloids and living cells in a highly miniaturized way. In contrast with impedance spectroscopy, the measurements are performed at a fixed frequency, providing real-time monitoring of the species traveling over the sensor. [...] Read more.

Impedance cytometry represents a technique that allows the electronic characterization of colloids and living cells in a highly miniaturized way. In contrast with impedance spectroscopy, the measurements are performed at a fixed frequency, providing real-time monitoring of the species traveling over the sensor. By measuring the electrical properties of particles in suspension, the dielectric characteristics (electric conductivity and capacitance) of both cells and particles can be readily determined. During the last years, this technique has been broadly investigated; however, it is still not trivial to differentiate particles of similar size based on their dielectric characteristics. A way to increase the discrimination abilities of this technique could be the integration of nanostructures into the impedance platforms. In this work, we present the impedance cytometry study of particles using microfluidic channels aligned over interdigitated gold nanowire structures as our impedimetric sensor. The characterization of particles of different sizes and their comparison with particles of different compositions will provide an understanding of the correlation between the electrical signal and the characteristics of each particle. This approach is an attractive element for label-free detection platforms that can be integrated into lab-on-a-chip systems and further implemented for single-cell analysis. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 159 KiB

Open AccessAbstract

ZnO/RGO Heterojunction Based near Room Temperature Alcohol SENSOR with Improved Efficiency

by Sanghamitra Ghosal and Partha Bhattacharyya

Eng. Proc. 2021, 6(1), 25; https://doi.org/10.3390/I3S2021Dresden-10073 - 17 May 2021

Viewed by 595

Abstract

The systematic optimization of surface engineering (dimensionality) indeed plays a crucial role in achieving efficient vapor-sensing performance. Among various semiconducting metal oxides, owing to some of its unique features and advantages, ZnO has attracted researchers on a global scale due to its application [...] Read more.

The systematic optimization of surface engineering (dimensionality) indeed plays a crucial role in achieving efficient vapor-sensing performance. Among various semiconducting metal oxides, owing to some of its unique features and advantages, ZnO has attracted researchers on a global scale due to its application in various fields, including chemical sensors. The concomitant optimization of the surface attributes (varying different dimensions) of ZnO have become a sensation for the entire research community. Moreover, the small thickness and extremely large surface of exfoliated 2D nanosheets render the gas sensing material an ideal candidate for achieving strong coupling with different gas molecules. However, temperature is a crucial factor in the field of chemical sensing. Recently, graphene-based gas sensors have attracted attention due to their variety of structures, unique sensing performances and room temperature working conditions. In this work, a highly sensitive and fast responsive low temperature (60 °C)-based ethanol sensor, based on RGO/2D ZnO nanosheets hybrid structure, is reported. After detailed characterizations, the vapor sensing potentiality of this sensor was tested for the detection of ethanol. The ethanol sensor offered the response magnitude of 89% (100 ppm concentration) with response and recovery time of 12 s/29 s, respectively. Due to excessively high number of active sites for VOC interaction, with high yield synthesis process and appreciably high carrier mobility, this has paved the way for developing future generation, miniaturized and flexible (wearable) vapor sensor devices, meeting the multidimensional requirements for traditional and upcoming (health/medical sector) applications. The underlying mechanistic framework for vapor sensing, using this hybrid junction, is explained with the Energy Band Diagram. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 164 KiB

Open AccessAbstract

Modifications of the PAMONO-Sensor Help to Size and Quantify Low Number of Individual Biological and Non-Biological Nano-Particles

by Rahat Morad Talukder, Al Shahriar Hossain Rakib, Julija Skolnik, Zohair Usfoor, Katharina Kaufmann, Roland Hergenröder and Victoria Shpacovitch

Eng. Proc. 2021, 6(1), 26; https://doi.org/10.3390/I3S2021Dresden-10136 - 17 May 2021

Viewed by 715

Abstract

In a series of recently published works, we demonstrated that the plasmon-assisted microscopy of nano-objects (PAMONO) technique can be successfully employed for the sizing and quantification of single viruses, virus-like particles, microvesicles and charged non-biological particles. This approach enables label-free, but specific detection [...] Read more.

In a series of recently published works, we demonstrated that the plasmon-assisted microscopy of nano-objects (PAMONO) technique can be successfully employed for the sizing and quantification of single viruses, virus-like particles, microvesicles and charged non-biological particles. This approach enables label-free, but specific detection of biological nano-vesicles. Hence, the sensor, which was built up utilizing plasmon-assisted microscopy, possesses relative versatility and it can be used as a platform for cell-based assays. However, one of the challenging tasks for such a sensor was the ability to reach a homogeneous illumination of the whole surface of the gold sensor slide. Moreover, in order to enable the detection of even relatively low concentrations of nano-particles, the focused image area had to be expanded. Both tasks were solved via modifications of previously described PAMONO-sensor set ups. Taken together, our latest findings can help to develop a research and diagnostic platform based on the principles of the surface plasmon resonance (SPR)-assisted microscopy of nano-objects. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 172 KiB

Open AccessAbstract

Hafnium Zirconium Oxide Thin Films for CMOS Compatible Pyroelectric Infrared Sensors

by Clemens Mart, Malte Czernohorsky, Kati Kühnel and Wenke Weinreich

Eng. Proc. 2021, 6(1), 27; https://doi.org/10.3390/I3S2021Dresden-10138 - 17 May 2021

Cited by 1 | Viewed by 737

Abstract

Pyroelectric infrared sensors are often based on lead-containing materials, which are harmful to the environment and subject to governmental restrictions. Ferroelectric Hf_1−xZr_xO₂ thin films offer an environmentally friendly alternative. Additionally, CMOS integration allows for integrated sensor circuits, [...] Read more.

Pyroelectric infrared sensors are often based on lead-containing materials, which are harmful to the environment and subject to governmental restrictions. Ferroelectric Hf_1−xZr_xO₂ thin films offer an environmentally friendly alternative. Additionally, CMOS integration allows for integrated sensor circuits, enabling scalable and cost-effective applications. In this work, we demonstrate the deposition of pyroelectric thin films on area-enhanced structured substrates via thermal atomic layer deposition. Scanning electron microscopy indicates a conformal deposition of the pyroelectric film in the holes with a diameter of 500 nm and a depth of 8 μm. By using TiN electrodes and photolithography, capacitor structures are formed, which are contacted via the electrically conductive substrate. Ferroelectric hysteresis measurements indicate a sizable remanent polarization of up to 331 μC cm⁻², which corresponds to an area increase of up to 15 by the nanostructured substrate. For pyroelectric analysis, a sinusoidal temperature oscillation is applied to the sample. Simultaneously, the pyroelectric current is monitored. By assessing the phase of the measured current profile, the pyroelectric origin of the signal is confirmed. The devices show sizable pyroelectric coefficients of −475 μC m⁻² K⁻¹, which is larger than that of lead zirconate titanate (PZT). Based on the experimental evidence, we propose Hf_1−xZr_xO₂ as a promising material for future pyroelectric applications. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 187 KiB

Open AccessAbstract

A Novel Vision-Based Approach for the Classification of Volcanic Ash Granulometry

by Bruno Andò, Salvatore Baglio, Vincenzo Marletta and Salvatore Castorina

Eng. Proc. 2021, 6(1), 28; https://doi.org/10.3390/I3S2021Dresden-10088 - 17 May 2021

Cited by 1 | Viewed by 524

Abstract

Volcanic ash fall-out represents a serious hazard for air and road traffic. The forecasting models used to predict its time–space evolution require information about characteristic parameters such as the ash granulometry. Typically, such information is gained by spot direct observation of the ash [...] Read more.

Volcanic ash fall-out represents a serious hazard for air and road traffic. The forecasting models used to predict its time–space evolution require information about characteristic parameters such as the ash granulometry. Typically, such information is gained by spot direct observation of the ash at the ground or by using expensive instrumentation. A distributed Wireless Sensor Network (WSN) of low-cost monitoring stations would represent a suitable solution in performing continuous and high spatial resolution monitoring. In this paper, a novel low-cost vision-based methodology, together with a dedicated image processing algorithm aimed at the estimation and classification of the ash granulometry, is presented. The first prototype developed to investigate the methodology consists of a light-controlled tank and a camera. The acquired images of the ash samples are transmitted to a PC and processed by a dedicated paradigm developed in LabVIEW™. A threshold algorithm was developed to provide a classification of the detected ash. Optimal thresholds were estimated by using the theory of receiver operating characteristic (ROC) curves. The methodology was validated experimentally using real ash erupted from Mount Etna, with three different nominal granulometries: ɸ₁ = 0.5 mm, ɸ₂ = 1 mm, and ɸ₃ = 2 mm. The preliminary results demonstrated the viability of the proposed approach, showing average accuracies in the estimation of the granulometry of 50 µm, suitable for the implementation of a low-cost distributed early warning solution. The main novelties of this work reside in both the low-cost vision-based methodology and the proposed classification algorithm. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 179 KiB

Open AccessAbstract

Low-Cost, High-Sensitivity Detection of Waterborne Al³⁺ Cations and F⁻ Anions via the Fluorescence Response of a Morin Derivative Dye

by Alhulw H. Alshammari, Zahrah Alqahtani, Faiz Bukhari Mohd Suah, Syaza Atikah Nizar, Alan Dunbar and Martin Grell

Eng. Proc. 2021, 6(1), 29; https://doi.org/10.3390/I3S2021Dresden-10166 - 20 May 2021

Viewed by 631

Abstract

Morin dye is known as a cheap and readily available selective ‘off → on’ fluorescent sensitiser when immobilised in a phase transfer membrane for the detection of Al³⁺ ions. Here, a morin derivative, NaMSA, which readily dissolves in water with good long-term [...] Read more.

Morin dye is known as a cheap and readily available selective ‘off → on’ fluorescent sensitiser when immobilised in a phase transfer membrane for the detection of Al³⁺ ions. Here, a morin derivative, NaMSA, which readily dissolves in water with good long-term stability is used in conjunction with a fibre-optic transducer with lock-in detection to detect Al³⁺ in drinking water below the potability limit. The combination of a water-soluble dye and the fibre-optic transducer require neither membrane preparation nor a fluorescence spectrometer yet still display a high figure of merit. The known ability to recover morin-based Al³⁺ cation sensors selectively by exposure to fluoride (F⁻) anions is further developed, enabling a complementary sensing of either fluoride anions, or aluminium cations, using the same dye with a sub-micromolar limit-of-detection for both ions. The sensor performance parameters compare favourably to prior reports on both aqueous aluminium and fluoride ion sensing. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 168 KiB

Open AccessAbstract

Small Force Sensor to Measure the Three Components of the Ground Reaction Forces in Mice

by Tayssir Limam, Florian Vogl and William R. Taylor

Eng. Proc. 2021, 6(1), 30; https://doi.org/10.3390/I3S2021Dresden-10083 - 17 May 2021

Viewed by 611

Abstract

The measurement of ground reaction forces (GRFs) helps in determining the role of each limb for support and propulsion in predicting muscle activities, and in determining the strain conditions experienced by bones. Measuring the GRFs in mice models is therefore a cornerstone for [...] Read more.

The measurement of ground reaction forces (GRFs) helps in determining the role of each limb for support and propulsion in predicting muscle activities, and in determining the strain conditions experienced by bones. Measuring the GRFs in mice models is therefore a cornerstone for understanding rodent musculoskeletal and neuromotor systems, as well as for improved translation of knowledge to humans. Current force plates are too big in size to allow the measurement of forces for each paw. This limitation is mainly due to the large size of the used sensors. The goal of our study was therefore to develop a small 3D force sensor for application in rodent gait analysis. We designed a flexible and small mechanical structure (8 mm × 8 mm) to isolate force components. Using FEM simulation, we chose the area with the highest strain to fix two strain gauges for each direction. The small size of the sensor allows us to fix four of them under a plate on the mouse paw size (approximately 17 mm). According to our primary results, the force plate has a resolution of 2 mN in the vertical direction and 1 mN in the fore-aft and mediolateral directions. The construction of a runway with such a force plate will allow the measurement of GRFs and the centre of pressure of each rodent paw for different steps. Such techniques thus provide a basis for assessing functionality in mice models, towards improved translation of rodent research. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 174 KiB

Open AccessAbstract

Hardware Passwords Manager Based on Biometric Authentication

by Camelia Avram, Jose Machado and Adina Aştilean

Eng. Proc. 2021, 6(1), 31; https://doi.org/10.3390/I3S2021Dresden-10085 - 17 May 2021

Cited by 1 | Viewed by 693

Abstract

This paper presents a portable passwords manager which has a two-stage biometric-based access procedure. Data security using biometric methods was chosen as a variant of reduced complexity but was very effective in preventing cyber theft. The implementation of biometrics for the purpose of [...] Read more.

This paper presents a portable passwords manager which has a two-stage biometric-based access procedure. Data security using biometric methods was chosen as a variant of reduced complexity but was very effective in preventing cyber theft. The implementation of biometrics for the purpose of identification in high-security systems has become essential with the evolution of technology and the spike in identity theft. Unlike passwords or IDs, a biometric feature is an identifier that cannot be lost, stolen, or replicated, which provides biometric authentication systems with an increased level of security. During the first accessing step, the 3DPassManager portable device measures the heartbeat and uses fingerprint and iris features to realize a unique biometric-based authentication. While the specific characteristics of fingerprint and iris features are integrated to ensure that the person using the device is the rightful owner, the pulse is utilized to verify if previously acquired static images are not used. During the second accessing step, a password is generated based on fingerprint details, valid only for a small-time interval. The fingerprint is stored in a secret key with a 1024-bit length. Once access is allowed, the passwords are made available through an extension installed on the web browser. The device is the size of a cigarette pack and communicates with the PC by scanning a QR code. It is safe and was previously tested for dictionary and brute force attacks. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 191 KiB

Open AccessAbstract

Investigation of the Thermally Generated Au and Ag Nanoislands for SERS and LSPR Applications

by Istvan Csarnovics, Miklos Veres, Attila Bonyár and Petra Pál

Eng. Proc. 2021, 6(1), 32; https://doi.org/10.3390/I3S2021Dresden-10153 - 18 May 2021

Viewed by 681

Abstract

Gold and silver nanoparticles are widely used as signal amplification elements in various electrochemical and optical sensor applications. Although these NPs can be synthesized in several ways, perhaps one of the simplest methods of their preparation is the thermal annealing of pre-deposited thin [...] Read more.

Gold and silver nanoparticles are widely used as signal amplification elements in various electrochemical and optical sensor applications. Although these NPs can be synthesized in several ways, perhaps one of the simplest methods of their preparation is the thermal annealing of pre-deposited thin metal films on glass. With this method, the parameters of the annealing process (time and temperature) and the pre-deposited thin film thickness influence and define the resulting size and distribution of the NPs on the surface. LSPR is a very sensitive optical phenomenon and can be utilized for a large variety of sensing purposes. SERS is an analytical method that can significantly increase the yield of the Raman scattering of target molecules adsorbed on the surface of metallic nanoparticles. In this work, the performance of Au/Ag nanoislands was investigated for SERS and LSPR applications. The nanoislands were generated by thermally annealing thin layers of silver and gold, which were previously sputtered onto glass surfaces. The sensitivity of LSPR and SERS-based devices were strongly dependent on the used material and the size and geometry of the metallic nanoparticles. By controlling these parameters, the plasmon absorption band can be tuned and the sensitivity can be optimized. This work was supported by the GINOP-2.3.2-15-2016-00041 project. ICs is grateful for the support of the János Bólyai Research Scholarship of the Hungarian Academy of Sciences. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

1 pages, 162 KiB

Open AccessAbstract

FLIM Indicators for Quantitative Measurement of pH

by Tatiana R. Simonyan, Anastasia V. Mamontova, Konstantin A. Lukyanov and Alexey M. Bogdanov

Eng. Proc. 2021, 6(1), 33; https://doi.org/10.3390/I3S2021Dresden-10144 - 17 May 2021

Viewed by 636

Abstract

Monitoring of intracellular pH changes in situ can provide valuable information about cellular metabolism and a deeper understanding of physiological processes. Most traditional fluorescent indicators are only capable of a relative assessment of changes in the studied parameter in the cell. We associate [...] Read more.

Monitoring of intracellular pH changes in situ can provide valuable information about cellular metabolism and a deeper understanding of physiological processes. Most traditional fluorescent indicators are only capable of a relative assessment of changes in the studied parameter in the cell. We associate the possibility of measuring the absolute values that characterize the analyte with the detection of the indicator signal in the time domain, where its quantitative measure is the fluorescence lifetime (tau). In this project, we test promising pH-sensitive fluorophores with labile fluorescence lifetimes—EYFP-G65T and EGFP-Y145L/S205V—both as fluorescent cores for the previously described pH indicators and as independent pH indicators. Measurement of the fluorescence attenuation kinetics of four structures (EYFP-G65T, EGFP-Y145L/S205V, SypHer3s, and SypHer3s-G65T) over a wide pH range revealed areas where tau is linearly dependent on pH. The differences in the fluorescence excitation modes of these molecules makes it possible to use them in one experimental system to assess pH changes in a wide range, 4.0–9.0. We showed that under the conditions of traditional fluorescence microscopy (in the cytoplasm of HEK293 cells), the SypHer3s-G65T indicator shows a dynamic response range approximately 3 times wider than the original SypHer3s. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

184 KiB

Open AccessAbstract

Implantable Blood Pressure Sensors with Analogic Thermal Drift Compensation

by Serigne Modou Die Mbacke, Mohammed El Gibari, Benjamin Lauzier, Chantal Gautier and Hongwu Li

Eng. Proc. 2021, 6(1), 34; https://doi.org/10.3390/I3S2021Dresden-10126 - 17 May 2021

Viewed by 621

Abstract

Implantable pressure sensors represent an important part of the research activity in laboratories. Unfortunately, their use is limited by cost, autonomy and temperature-related drifts. The cost of use depends on several parameters, particularly their low battery life and the need for miniaturization to [...] Read more.

Implantable pressure sensors represent an important part of the research activity in laboratories. Unfortunately, their use is limited by cost, autonomy and temperature-related drifts. The cost of use depends on several parameters, particularly their low battery life and the need for miniaturization to be able to implant the animals and monitor them over a time that is long enough to be physiologically relevant. This paper studied the possibility of reducing the thermal drift of implantable sensors. To quantify and compensate for the thermal drift, we developed the equivalent model of the piezoresistive probe by using the Cadence software. Our model takes into account the temperature (34–39 °C) as well as the pressure (0–300 mmHg). We were thus able to identify the source of the drift and thanks to our model, we were able to compensate for it thanks to the compensation circuits added to the conditioning circuits of the sensor. The maximum relative drift of the sensor is (0.1 mV/°C)/3.6 mV (2.7%), a drift of the conditioning circuit is (0.98 mV/°C)/916 mV (0.1%) and the whole is (13.4 mV/°C)/420 mV (32%). The compensated sensor shows a relative maximum drift of (0.371 mV/°C)/405 mV (0.09%). The output voltage remains stable over the measurement temperature range. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

153 KiB

Open AccessAbstract

Probabilistic Modelling for Unsupervised Analysis of Human Behaviour in Smart Cities

by Yazan Qarout, Yordan P. Raykov and Max A. Little

Eng. Proc. 2021, 6(1), 35; https://doi.org/10.3390/I3S2021Dresden-10099 - 17 May 2021

Viewed by 584

Abstract

The growth of urban areas in recent years has motivated a large amount of new sensor applications in smart cities. At the centre of many new applications stands the goal of gaining insights into human activity. Scalable monitoring of urban environments can facilitate [...] Read more.

The growth of urban areas in recent years has motivated a large amount of new sensor applications in smart cities. At the centre of many new applications stands the goal of gaining insights into human activity. Scalable monitoring of urban environments can facilitate better informed city planning, efficient security, regular transport, and commerce. A large part of monitoring capabilities have already been deployed; however, most rely on expensive motion imagery and privacy invading video cameras. It is possible to use a low-cost sensor alternative which enables deep understanding of population behaviour, such as the Global Positioning System (GPS) data. However, the automated analysis of such low-dimensional sensor data requires new flexible and structured techniques that can describe the generative distribution and time dynamics of the observation data, while accounting for external contextual influences such as time of day, or the difference between weekend/weekday trends. We propose a novel time series analysis technique that allows for multiple different transition matrices depending on the data’s contextual realisations, all following shared adaptive observational models that govern the global distribution of the data given a latent sequence. The proposed approach, which we name Adaptive Input Hidden Markov model (AI-HMM), is tested on two datasets from different sensor types: GPS trajectories of taxis and derived vehicle counts in populated areas. We demonstrate that our model can group different categories of behavioural trends and identify time specific anomalies. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

171 KiB

Open AccessAbstract

Low-Frequency Magnetic Localization of Capsule Endoscopes with an Integrated Coil

by Samuel Zeising, Rebecca Seidl, Angelika Thalmayer, Georg Fischer and Jens Kirchner

Eng. Proc. 2021, 6(1), 38; https://doi.org/10.3390/I3S2021Dresden-10146 - 17 May 2021

Viewed by 736

Abstract

Wireless capsule endoscopy is a promising and less invasive alternative to conventional endoscopy. A patient swallows a small capsule with an integrated camera to capture a video of the gastrointestinal tract. For accurate diagnosis and therapy, the capsule position in terms of the [...] Read more.

Wireless capsule endoscopy is a promising and less invasive alternative to conventional endoscopy. A patient swallows a small capsule with an integrated camera to capture a video of the gastrointestinal tract. For accurate diagnosis and therapy, the capsule position in terms of the travelled distance must be known for each video frame. However, to date, there is no reliable localization method for endoscopy capsules. In this paper, a novel magnetic localization method is proposed. A coil as a magnetic field source is integrated into a capsule and fed with a low-frequency alternating current to prevent static geomagnetic field interference. This alternating magnetic field is measured by twelve magnetic sensors arranged in rings around the abdomen. The coil and the capsule batteries were designed based on the geometry and power supply of a commercially available endoscopy capsule and simulated by COMSOL Multiphysics software. In this way, the coil position and orientation were determined with an accuracy below 1 mm and 1°, respectively. As an analytic model for the magnetic flux density of the coil in that setup, a modified dipole model was derived. It was used to show that the batteries help to increase the amplitude of the magnetic flux density. The model is valid when signals below 100 Hz are applied, and no eddy currents are generated within the batteries. It is concluded that the magnetic flux density generated by the developed coil would be measurable with state-of-the-art magnetic sensors. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

2935 KiB

Open AccessAbstract

A Study of Visible-Blind Properties of a SnO₂’s Nanowires Network Photodetector

by Estácio P. de Araújo, Adryelle N. Arantes, Ivani M. Costa and Adenilson J. Chiquito

Eng. Proc. 2021, 6(1), 40; https://doi.org/10.3390/I3S2021Dresden-10149 - 17 May 2021

Viewed by 1077

Abstract

Summary: We developed an SnO₂ nanowire network visible-blind ultraviolet (UV) photodetector for applications in fields such as safety systems, exposure control, and decontamination processes, among others [...] Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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189 KiB

Open AccessAbstract

Detection of Biogenic Amines in Canned Tuna Using a Voltammetric Electronic Tongue

by Marta Bonet-San-Emeterio, Maria Bruguera-Jané, Xavier Cetó and Manel del Valle

Eng. Proc. 2021, 6(1), 41; https://doi.org/10.3390/I3S2021Dresden-10169 - 21 May 2021

Viewed by 791

Abstract

Biogenic amines (BAs), which are produced naturally due to the decomposition of amino acids, are crucial for the food industry because its formation is directly related to improper storage and the presence of bacteria. High concentrations of BAs can be easily related with [...] Read more.

Biogenic amines (BAs), which are produced naturally due to the decomposition of amino acids, are crucial for the food industry because its formation is directly related to improper storage and the presence of bacteria. High concentrations of BAs can be easily related with the quality and spoilage of the products of this sector. The necessity to quickly and efficiently quantify these targets makes mandatory the use of alternatives to conventional analytical methods used up to now. For example, the combination of sensors with chemometric tools (known as electronic tongue) are a promising alternative for quick and informative analysis in the food sector. Chemometric tools allow us to develop models for the quantification of specific compounds in a complex matrix, making it a feasible tool for the development of more user-friendly methods than the traditional ones. In this context, the work presents an electronic tongue created for the detection of histamine, cadaverine and tyramine using a set of five modified GEC (graphite epoxy composite) electrodes: ZnO NPs, CuO NPs, SnO₂ NPs, Bi₂O₃ NPs, and polypyrrole, as the voltammetric multisensor array. The chemometric model was obtained with an Artificial Neural Network (ANN) with 51 input neurons, five neurons in the hidden layer and three neurons in the output layer. The functions used for the hidden and output layers were tansig and purelin, respectively. The results show slopes near to 1 and intercepts close to 0, indicating the feasibility of the model. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

163 KiB

Open AccessAbstract

Acetone Bio-Sniffer (Gas-Phase Biosensor) for Monitoring of Human Volatile Using Enzymatic Reaction of Secondary Alcohol Dehydrogenase

by Takahiro Arakawa, Ming Ye, Kenta Iitani, Koji Toma and Kohji Mitsubayashi

Eng. Proc. 2021, 6(1), 45; https://doi.org/10.3390/I3S2021Dresden-10165 - 20 May 2021

Viewed by 710

Abstract

We developed a highly sensitive acetone bio-sniffer (gas-phase biosensor) based on an enzyme reductive reaction to monitor breath acetone concentration. The acetone bio-sniffer device was constructed by attaching a flow-cell with nicotinamide adenine dinucleotide (NADH)-dependent secondary alcohol dehydrogenase (S-ADH) immobilized membrane onto a [...] Read more.

We developed a highly sensitive acetone bio-sniffer (gas-phase biosensor) based on an enzyme reductive reaction to monitor breath acetone concentration. The acetone bio-sniffer device was constructed by attaching a flow-cell with nicotinamide adenine dinucleotide (NADH)-dependent secondary alcohol dehydrogenase (S-ADH) immobilized membrane onto a fiber-optic NADH measurement system. This system utilizes an ultraviolet light emitting diode as an excitation light source. Acetone vapor was measured as the fluorescence of NADH consumption by the enzymatic reaction of S-ADH. A phosphate buffer that contained oxidized NADH was circulated into the flow-cell to rinse the products and the excessive substrates from the optode; thus, the bio-sniffer enables the real-time monitoring of acetone vapor concentration. A photomultiplier tube detects the change in the fluorescence emitted from NADH. The relationship between the fluorescence intensity and acetone concentration was identified to be from 20 ppb to 5300 ppb. This encompasses the range of concentration of acetone vapor found in the breath of healthy people and of those suffering from disorders of carbohydrate metabolism. Then, the acetone bio-sniffer was used to monitor the exhaled breath acetone concentration change before and after a meal. When the sensing region was exposed to exhaled breath, the fluorescence intensity decreased and reached saturation immediately. Then, it returned to the initial state upon cessation of the exhaled breath flow. We anticipate its future use as a non-invasive analytical tool for the assessment of lipid metabolism in exercise, fasting and diabetes mellitus. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

161 KiB

Open AccessAbstract

Using Interdigitated Organic Electrochemical Transistors as Electrophysiological and Biochemical Sensors

by Dirk Mayer

Eng. Proc. 2021, 6(1), 46; https://doi.org/10.3390/I3S2021Dresden-10133 - 17 May 2021

Viewed by 578

Abstract

Organic electrochemical transistors (OECTs) have emerged as versatile electrophysiological sensors due to their high transconductance, biocompatibility, and transparent channel material. High maximum transconductances were demonstrated, facilitating extracellular recordings from electrogenic cells. However, this often requires large channel dimensions which impede high transistor densities. [...] Read more.

Organic electrochemical transistors (OECTs) have emerged as versatile electrophysiological sensors due to their high transconductance, biocompatibility, and transparent channel material. High maximum transconductances were demonstrated, facilitating extracellular recordings from electrogenic cells. However, this often requires large channel dimensions which impede high transistor densities. To improve the device performance and density, we used interdigitated OECTs (iOECTs), which feature high transconductances with small device areas. Superior device performance was achieved by systematically optimizing the electrode layout regarding channel length, number of electrode digits, and electrode width. Interestingly, the maximum transconductance does not straightforwardly scale with the channel width-to-length ratio, which is different from planar OECTs. We used optimized iOECTs for recording action potentials of cardiomyocyte-like HL-1 cells. Furthermore, we embedded the iOECTs in a matrix of polyimide to achieve flexible and transparent bioelectronic devices. These sensors exhibited electrical characteristics similar to those of solid-substrate devices even after experiencing extremely high bending strain. Finally, we used these devices to detect neurotransmitter dopamine and ATP, which play an important role not only in signal transmission in the central nervous system but also in cardiovascular, neurodegenerative, and immune deficiency diseases. Our novel aptasensor possessed ultralow detection limits, which were several orders of magnitude lower than those of the same aptasensors using an amperometric transducer principle. Our results demonstrate that interdigitated OECTs meet two requirements of both electrophysiological and biochemical sensors, namely high device performance and small channel dimensions, and might represent the optimal transducer to integrate these two types of sensors on one chip. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

202 KiB

Open AccessAbstract

Two Orders of Magnitude Improvement in the Detection Limit of Droplet-Based Micro-Magnetofluidics with Planar Hall Effect Sensors

by Julian Schütt, Rico Illing, Oleksii Volkov, Tobias Kosub, Pablo Nicolás Granell, Hariharan Nhalil, Jürgen Fassbender, Lior Klein, Asaf Grosz and Denys Makarov

Eng. Proc. 2021, 6(1), 47; https://doi.org/10.3390/I3S2021Dresden-10105 - 17 May 2021

Viewed by 736

Abstract

The detection, manipulation, and tracking of magnetic nanoparticles is of major importance in the fields of biology, biotechnology, and biomedical applications as labels as well as in drug delivery, (bio-)detection, and tissue engineering. In this regard, the trend goes towards improvements of existing [...] Read more.

The detection, manipulation, and tracking of magnetic nanoparticles is of major importance in the fields of biology, biotechnology, and biomedical applications as labels as well as in drug delivery, (bio-)detection, and tissue engineering. In this regard, the trend goes towards improvements of existing state-of-the-art methodologies in the spirit of timesaving, high-throughput analysis at ultra-low volumes. Here, microfluidics offers vast advantages to address these requirements, as it deals with the control and manipulation of liquids in confined microchannels. This conjunction of microfluidics and magnetism, namely micro-magnetofluidics, is a dynamic research field, which requires novel sensor solutions to boost the detection limit of tiny quantities of magnetized objects. We present a sensing strategy relying on planar Hall effect (PHE) sensors in droplet-based micro-magnetofluidics for the detection of a multiphase liquid flow, i.e., superparamagnetic aqueous droplets in an oil carrier phase. The high resolution of the sensor allows the detection of nanoliter-sized superparamagnetic droplets with a concentration of 0.58 mg cm⁻³, even when they are only biased in a geomagnetic field. The limit of detection can be boosted another order of magnitude, reaching 0.04 mg cm⁻³ (1.4 million particles in a single 100 nL droplet) when a magnetic field of 5 mT is applied to bias the droplets. With this performance, our sensing platform outperforms the state-of-the-art solutions in droplet-based micro-magnetofluidics by a factor of 100. This allows us to detect ferrofluid droplets in clinically and biologically relevant concentrations, and even in lower concentrations, without the need of externally applied magnetic fields. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

178 KiB

Open AccessAbstract

Flexible Piezoelectric Thin Films for Podiatric Sensors with Wireless Communication

by Samia Adrar, Mohammed El Gibari, Philippe Saillant, Arnaud Chambellan, Marc Jubeau and Raynald Seveno

Eng. Proc. 2021, 6(1), 48; https://doi.org/10.3390/I3S2021Dresden-10127 - 17 May 2021

Viewed by 659

Abstract

For reasons of availability and cost, patients are sent home increasingly early, with limited follow-up due to the complexity and size of medical devices. In this context, researchers from IETR and MIPS laboratories are working on a device which should monitor the progress [...] Read more.

For reasons of availability and cost, patients are sent home increasingly early, with limited follow-up due to the complexity and size of medical devices. In this context, researchers from IETR and MIPS laboratories are working on a device which should monitor the progress of a patient, in order to detect early the aggravation of a disease such as Chronic Obstructive Pulmonary Disease (COPD) or diabetes with walking disorders. The device is based on flexible piezoelectric thin films (3 µm thick) that can be used as podiatric sensors and have been developed by the IETR laboratory. The originality of this work lies both in the approach to the design of the gait-monitoring device—because it was carried out directly in consultation with a doctor from the University Hospital of Nantes and a podiatrist—and in the portability of the device, which should eventually allow the follow-up of a patient at home. For this study, the flexible piezoelectric sensors have been elaborated using a Chemical Solution Deposition (CSD) process and a commercial aluminum (Al) foil as substrate. In order to increase the flexibility of sensors and to aid its insertion in a shoe, piezoelectric films have been encapsulated by lamination into polyethylene terephthalate (PET, 150 μm). In this paper, the elaboration and characterization of flexible piezoelectric sensors, analog-to-digital converter and wireless communication protocol used for data transmission are presented. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

171 KiB

Open AccessAbstract

Development of a Metrological Atomic Force Microscope System with Improved Signal Quality

by Yiting Wu, Elisa Wirthmann, Ute Klöpzig and Tino Hausotte

Eng. Proc. 2021, 6(1), 49; https://doi.org/10.3390/I3S2021Dresden-10102 - 17 May 2021

Viewed by 694

Abstract

This article presents a new metrological atomic force microscope (MAFM) with a homodyne interferometer and a tilt measuring system by a position sensitive device (PSD). The combination allows simultaneous three-dimensional detection of the tip displacement by capturing the position, bending and torsion of [...] Read more.

This article presents a new metrological atomic force microscope (MAFM) with a homodyne interferometer and a tilt measuring system by a position sensitive device (PSD). The combination allows simultaneous three-dimensional detection of the tip displacement by capturing the position, bending and torsion of a reflecting surface of the cantilever realized with one laser beam. Based on an existing interferometric measuring head of a micro-tactile 3D probe, the sensor head was revised and adapted for atomic force microscopy. The new measuring system uses two tiltable plane mirrors to adjust the direction and position of a focused laser beam. With this adjustment unit, the focused laser beam can be steered perpendicular to the reflecting backside of the cantilever. Regarding the probe system, the optical design of the measuring head has been reengineered to reduce the disturbing interference on the PSD. A simulation applying the optical design program OpticStudio from Zemax shows that the integration of two wedge plates with a wedge angle of 0.5° reduces the disturbing interference significantly. After manufacturing, initial measurement results are presented to verify the functionality. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

190 KiB

Open AccessAbstract

Coupling of Sensors and Machine Learning Algorithms in the Qualitative Analysis of Wine

by Anna Herrera-Chacon, Inmaculada Campos, Andreu González-Calabuig, Mireia Torres and Manel del Valle

Eng. Proc. 2021, 6(1), 50; https://doi.org/10.3390/I3S2021Dresden-10117 - 17 May 2021

Cited by 1 | Viewed by 846

Abstract

This work attempts the identification of the production year, the cultivar’s region and the aging method used in the elaboration of different Spanish red wines, all from the “tempranillo” grape variety. The identification of such characteristics relies on the use of a voltammetric [...] Read more.

This work attempts the identification of the production year, the cultivar’s region and the aging method used in the elaboration of different Spanish red wines, all from the “tempranillo” grape variety. The identification of such characteristics relies on the use of a voltammetric electronic tongue (ET) system formed by modified graphite-epoxy electrodes (GEC) and metallic electrodes to collect a set of six voltammograms per sample, and different chemometric tools to accomplish the final identifications. A large sample set that included 199 different wine samples from commercial and own elaboration origin were analysed with the electronic tongue system, using the cyclic voltammetry technique and without any sample pre-treatment. To process the extremely complex and high-dimensionality generated data, a compression strategy was used for the acquired voltammograms, using discrete wavelet transform (DWT). This treatment reduced the information to ca. 10%, preserving significant features from the voltammetric signals. Compressed data was evaluated firstly by unsupervised methods, i.e., principal component analysis (PCA), without much success as it was found that such methods were unable to unravel the patterns contained within such complex data samples. Finally, the processed electrochemical information was evaluated by supervised methods to accomplish the proper identification; among those methods were linear discriminant analysis (LDA), supported vector machines (SVM) or artificial neural networks (ANN). The best results were obtained using artificial neural networks (ANNs), achieving 96.1% of correct classification for bottled year, 86.8% for elaboration region (protected designation of origin) and 98.6% for maturation type with or without use of wood barrel. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

171 KiB

Open AccessAbstract

Possibility Noninvasive Detection Magnetic Particles in Biological Objects

by Levan P. Ichkitidze, Mikhail V. Belodedov, Alexander Yu. Gerasimenko, Dmitry V. Telyshev and Sergei V. Selishchev

Eng. Proc. 2021, 6(1), 61; https://doi.org/10.3390/I3S2021Dresden-10137 - 17 May 2021

Cited by 1 | Viewed by 636

Abstract

We evaluated the minimum concentration and minimum size within which magnetic particles (MPs) can be detected by modern ultra-sensitive magnetic field sensors (MFS). Calculations showed that magnetite MPs with specific magnetization with characteristic sizes of ≥50 nm and a concentration of C_V [...] Read more.

We evaluated the minimum concentration and minimum size within which magnetic particles (MPs) can be detected by modern ultra-sensitive magnetic field sensors (MFS). Calculations showed that magnetite MPs with specific magnetization with characteristic sizes of ≥50 nm and a concentration of C_V~0.1 vol.% can be detected at a distance of l ≤ 0.1 mm using MFS with a magnetic field resolution of S_B ≥ 1 nT. However, at such a close distance it is impossible to non-invasively approach the biological object of study. On the other hand, the same MPs are easily detected at l ≤ 30 mm using supersensitive MFS based on the phenomena of superconductivity (SQUID) or superconductivity and spintronics (combined MFS (CMFS)). These sensors require cryogenic operating temperatures (4–77 K), and S_B~10–100 fT are realized within them. Note that superparamagnetic particles or carbon nanotubes (CNTs) can also be non-invasively detected by SQUID or CMFS sensors, assuming that their concentration in the material is C_V ≥ 0.0000001 vol.%. It is believed that CNTs may contain catalytic iron particles or encapsulated magnetic nanoparticles in nanotubes. Thus, modern supersensitive magnetic field sensors with S_B ≤ 100 fT make it possible to detect MPs in nanoscale, submicron, and micron sizes in biological objects. They can be used for the noninvasive control of organs, implants, prostheses and drug carriers in the necessary parts of the body. Of particular importance is the noninvasive control of CNTs in functional biocompatible nanomaterials, which have good prospects for widespread use in medical practice. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

160 KiB

Open AccessAbstract

Aerial Cooperative SLAM for Ground Mobile Robot Path Planning

by Juan-Carlos Trujillo, Rodrigo Munguia and Antoni Grau

Eng. Proc. 2021, 6(1), 65; https://doi.org/10.3390/I3S2021Dresden-10164 - 20 May 2021

Viewed by 690

Abstract

The trajectory planning for ground mobile robots operating in unknown environments can be a difficult task. In many cases, the sensors used for detecting obstacles only provide information about the immediate surroundings, making it difficult to generate an efficient long-term path. For instance, [...] Read more.

The trajectory planning for ground mobile robots operating in unknown environments can be a difficult task. In many cases, the sensors used for detecting obstacles only provide information about the immediate surroundings, making it difficult to generate an efficient long-term path. For instance, a robot can easily choose to move along a free path that, eventually, will have a dead end. This research is intended to develop a cooperative scheme of visual-based aerial simultaneous localization and mapping (SLAM) that will be used for generating a safe long-term trajectory for a ground mobile robot. The general idea is to take advantage of the high-altitude point of view of aerial robots to obtain spatial information of a wide area of the surroundings of the robot. In this case, it could be seen as having a zenithal picture of the labyrinth to solve the robot’s path. More specifically, the system will generate a wide area spatial map of the ground robot’s obstacles from the images taken by a team of aerial robots equipped with onboard cameras, by means of a cooperative visual-based SLAM method. At the same time, the map will be used to generate a safe path for the ground mobile robot. While the ground robot moves, its onboard sensors will be used to refinine the map and, thus, to avoid obstacles that were not detected from the aerial images. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

159 KiB

Open AccessAbstract

Enriching Low-Density Terrain Maps from Satellite with Autonomous Robots Data

by Edmundo Guerra, Antoni Grau, Yolanda Bolea and Rodrigo Munguia

Eng. Proc. 2021, 6(1), 66; https://doi.org/10.3390/I3S2021Dresden-10157 - 19 May 2021

Viewed by 575

Abstract

Satellite imagery and remote sensoring have been used for some years in agriculture to create terrain maps for different soil features (humidity, vegetation index, etc.). Multichannel information provides lots of data, but with a big drawback: the low density of information per surface [...] Read more.

Satellite imagery and remote sensoring have been used for some years in agriculture to create terrain maps for different soil features (humidity, vegetation index, etc.). Multichannel information provides lots of data, but with a big drawback: the low density of information per surface unit; that is, the multi-channeled pixels correspond to a large surface, and a fine characterization of the targeted areas is not possible. In this research, the authors propose the enrichment of such data by the use of autonomous robots that explore and sense the same targeted area of the satellite but yielding a finer detail of terrain, complementing and fusing both information sources. The sensory elements of the autonomous robots are in the visual spectrum as well as in the near-infrared spectrum, together with Lidar and radar information. This enrichment will provide a high-density map of the soil to the final user to improve crops, irrigation, seeding and other agricultural processes. The methodology to fuse data and create high-density maps will be deep learning techniques. The system will be validated in real fields with the use of real sensors to measure the data given by satellites and robots’ sensors. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

185 KiB

Open AccessAbstract

Integration of an Optical Setup for the Characterization of Near-Infrared Detectors Used in Ground and Space-Based Astronomy

by Jorge Jimenez and Antoni Grau

Eng. Proc. 2021, 6(1), 68; https://doi.org/10.3390/I3S2021Dresden-10152 - 18 May 2021

Cited by 1 | Viewed by 561

Abstract

To make Europe competitive in the field of astronomical sensors and detectors, the main goal of this research is to provide the capability to manufacture high performance infrared focal plane arrays (FPA) devoted to scientific and astronomical ground and space telescope missions. This [...] Read more.

To make Europe competitive in the field of astronomical sensors and detectors, the main goal of this research is to provide the capability to manufacture high performance infrared focal plane arrays (FPA) devoted to scientific and astronomical ground and space telescope missions. This paper presents the main outcome of an international project with the highest standard of quality for this detector. The resulting detector is a sensor with a hybridized MCT (HgCdTe) epilayer on a CdZnTe substrate of 2 k × 2 k pixels and 15 μm of pixel pitch. On this framework, an optical setup has been developed at the IFAE optical laboratory with the capabilities to perform the characterization of a near-infrared (NIR) detector covering the range from 800 to 2500 nm. The optical setup is mainly composed of a power controlled quartz–halogen (QTH) lamp and an astigmatism-corrected Czerny–Turner monochromator with two diffraction gratings covering the detector wavelength range with a minimum resolution of ∼1 nm. A temperature stabilized gold-coated integration sphere provides a uniform and monochromatic illumination, while an InGaAs photodiode located at the north pole of the integration sphere is used to measure the radiant flux toward the detector. The whole setup is fully controlled by a Labview™ application and synchronized with the detector’s readout electronic (ROE). Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

176 KiB

Open AccessAbstract

Polyaniline Nanocomposites for Hydrogen Sulfide Detection at ppb Level

by Caroline Duc, Mohamed-Lamine Boukhenane, Thomas Fagniez, Nathalie Redon and Jean-Luc Wojkiewicz

Eng. Proc. 2021, 6(1), 69; https://doi.org/10.3390/I3S2021Dresden-10183 - 25 May 2021

Viewed by 903

Abstract

Coming from natural and anthropogenic sources, hydrogen sulfide gas (H₂S) is a smelly hazardous substance at the sub-ppm level, which can lead to poisoning deaths at higher concentrations. New sensors with high metrological properties (detection limit lower than 1 ppm) and [...] Read more.

Coming from natural and anthropogenic sources, hydrogen sulfide gas (H₂S) is a smelly hazardous substance at the sub-ppm level, which can lead to poisoning deaths at higher concentrations. New sensors with high metrological properties (detection limit lower than 1 ppm) and good stability are still needed to monitor and control the risk associated with this gas. The properties of a high-performance hydrogen sulfide gas sensor based on tin oxide and conductive polymers (polyaniline and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) are investigated. The principle of detection of this resistive sensor consists of a two steps reaction. H₂S reacts with tin oxide producing hydrochloride acid, which dopes polyaniline, leading to the increase of its conductivity. Those systems present high repeatability and reproducibility, with sensitivities around 10%/ppm and a limit of detection close to 30 ppb. Moreover, the effect of interfering species such as humidity and oxidative gases (ammonia) is addressed. Those species have a limited impact, corrigible by data treatment. Finally, the sensors present an increase of sensitivity with time, apparently due to the modification of the interface between the electrodes and the sensitive materials. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

162 KiB

Open AccessAbstract

A Novel, Reliable and Real-Time Solution for Triage and Unique Identification of Victims of Mass Casualty Incidents

by Fay Misichroni, Angelos Stamou, Paul Kuqo, Nikolaos Tousert, Anastasios Rigos, Evangelos Sdongos and Angelos Amditis

Eng. Proc. 2021, 6(1), 72; https://doi.org/10.3390/I3S2021Dresden-10180 - 25 May 2021

Viewed by 827

Abstract

A mass casualty incident may result in tens or hundreds of victims. Triage, being the procedure of classifying victims according to their medical emergency, and the unique identification of victims are equally crucial procedures for effectively managing the crisis with respect to personnel [...] Read more.

A mass casualty incident may result in tens or hundreds of victims. Triage, being the procedure of classifying victims according to their medical emergency, and the unique identification of victims are equally crucial procedures for effectively managing the crisis with respect to personnel (emergency medical services and non-medical civil protection practitioners) and assets (ambulances, medical equipment, hospital beds, etc.). The solution developed in this work aims at reducing the time needed for triage and identification procedures, and at the same time enhancing the situation awareness of crisis managers. Our system consists of (a) electronic wearable triage tags, aiming at replacing the legacy paper tags, supporting enhanced actuating and connectivity functionalities, visually presenting the status of the medical emergency of the victims and uniquely identifying them, (b) a mobile application, connected in real time with a cloud-based data aggregation node, enabling the emergency personnel to control the wearable device and to record the personal and medical emergency information of the victims, (c) an interoperability layer, supporting different connectivity options and capable of secure and reliable distribution of the collected data to multiple systems, such as Command and Control (C2s) systems of civil protection agencies, and (d) a web application, graphically presenting the victims’ medical emergencies and their personal information in aggregated and in-detail views, intended to be utilized by crisis managers in tactical and strategic levels of command. The efficiency of our system has been demonstrated in multiple civil protection full-scale exercises across Europe. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

161 KiB

Open AccessAbstract

Gas-Phase Chemical Imaging System by Biofluorometry for Human VOCs Measurement

by Kenta Iitani, Koji Toma, Takahiro Arakawa and Kohji Mitsubayashi

Eng. Proc. 2021, 6(1), 73; https://doi.org/10.3390/I3S2021Dresden-10181 - 25 May 2021

Viewed by 522

Abstract

Many gas-phase biosensors have been developed for human volatiles (acetone, methyl mercaptan, trimethylamine, ethanol, isopropanol, etc.) and for residential harmful VOCs (formaldehyde, toluene, nicotine) causing some diseases. A novel gas-imaging system by biofluorometry with an enzyme immobilized mesh was investigated to demonstrate spatiotemporal [...] Read more.

Many gas-phase biosensors have been developed for human volatiles (acetone, methyl mercaptan, trimethylamine, ethanol, isopropanol, etc.) and for residential harmful VOCs (formaldehyde, toluene, nicotine) causing some diseases. A novel gas-imaging system by biofluorometry with an enzyme immobilized mesh was investigated to demonstrate spatiotemporal gas-imaging for human volatiles (i.e., ethanol and acetaldehyde after drinking). A biofluorometric technique was applied to improve the performance (sensitivity, calibration range, gas-selectivity, etc.) of the gas-imaging system. The biofluorometric sniff-cam for ethanol was fabricated with an ADH (alcohol dehydrogenase) immobilized mesh and an NADH fluorescent visualization unit (UV-LED sheet array and highly sensitive camera); thus, showing the two-dimensional real-time imaging of ethanol vapor distribution (0.5–200 ppm). The system showed rapid and accurate responses and a visible measurement of ethanol in the gas phase. The intensity of fluorescence was linearly related to the concentration of ethanol vapor. The high sensitivity fluorescent imaging of ethanol vapor allows to successfully visualize gaseous ethanol from the human body (exhaled air and skin gas) after drinking. The sniff-cam system would be useful for the conventional detecting and imaging of the volatile biomarkers. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

178 KiB

Open AccessAbstract

DEM Embedding in GNSS-Based Navigation Using a Statistical Modeling

by Christophe Boucher, Hiba Al-Assaad, Ali Daher, Ahmad Shahin and Jean-Charles Noyer

Eng. Proc. 2021, 6(1), 74; https://doi.org/10.3390/I3S2021Dresden-10100 - 17 May 2021

Cited by 1 | Viewed by 740

Abstract

Given the boom linked to smart mobility, transport systems require increasingly precise and relevant navigation applications to offer optimized journeys in terms of time and energy consumption, such as for HEV. Most of these navigation applications are based on the processing of 2D [...] Read more.

Given the boom linked to smart mobility, transport systems require increasingly precise and relevant navigation applications to offer optimized journeys in terms of time and energy consumption, such as for HEV. Most of these navigation applications are based on the processing of 2D digital road maps, while taking into account the GNSS location of vehicles. These localization systems also integrate sensors such as accelerometers and gyroscopes to overcome the well-known problems of GPS positioning, even if the current limited introduction of IoT in the transport industry has made it possible to develop new aided-GPS methods such as geofencing. This paper focuses on one important parameter in the journey optimization of land vehicles: the road slope. We propose a method to estimate the roads’ inclination parameters by fusing GNSS, INS, OSM and ASTER GDEM data through a nonlinear filter. The incremental estimate of the slope will complement the 2D modeling of the roads already available in OpenStreetMap and could be used in route planning optimization. The scientific novelty lies more specifically in the statistical map-matching approaches that we develop both for OSM and DEM data. Estimation results of the roads slopes are shown in experimental conditions. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

160 KiB

Open AccessAbstract

Prototyping Platform for Laser-Based Sensor Technologies: Inspection of Conversion Coatings on Alumina

by Yannic Toschke, Joerg Rischmueller and Mirco Imlau

Eng. Proc. 2021, 6(1), 77; https://doi.org/10.3390/I3S2021Dresden-10121 - 17 May 2021

Viewed by 562

Abstract

Transferring laser-based sensors into industrial applications (for instance, for contact and destruction-free inline quality control of alumina alloys) is very challenging due to laser-safety regulations and the complex implementation requirements of individual technological infrastructures. In order to open laser-based sensor technology even for [...] Read more.

Transferring laser-based sensors into industrial applications (for instance, for contact and destruction-free inline quality control of alumina alloys) is very challenging due to laser-safety regulations and the complex implementation requirements of individual technological infrastructures. In order to open laser-based sensor technology even for small to medium size enterprises, we introduce a prototyping platform for laser-based sensor technologies that enables fast, error-free, flexible and low-cost transformations in the industry. As an example, the transformation of a laser-based sensor concept using coherent light scattering at technical insulating films is shown. The transformation of this type of sensor for inline quality control is particularly demanding due to the requirements of probing transparent conversion coatings (with a thickness of less than 70 nm) that commonly applied electronic techniques fail to affect. The conversion films are produced on the top of cold-rolled, unpolished alumina so that coherently scattered laser light is regarded as superposition from diffuse scattering processes at the surfaces/interfaces, inclusions, and/or layer imperfections. Analysis is realized by extending the principal approach of reflectometry and considering the role of diffuse and specular scattering together with the concepts of light interferometry. The functionality of the transformed sensor was successfully validated using five different conversion coating thicknesses on AA3003 alumina substrates. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

205 KiB

Open AccessAbstract

Multisensing Wearable Technology for Sweat Biomonitoring

by Meritxell Rovira, César Fernández-Sánchez, Silvia Demuru, Paul Kunnel Brince, Danick Briand and Cecilia Jimenez-Jorquera

Eng. Proc. 2021, 6(1), 78; https://doi.org/10.3390/I3S2021Dresden-10113 - 17 May 2021

Cited by 1 | Viewed by 980

Abstract

This work describes a multisensing wearable platform for monitoring biomarkers in sweat during the practice of exercise. Five electrochemical sensors for pH, potassium, sodium, chloride, and lactate were implemented in a flexible patch approach, together with a paper microfluidic component, to continuously measure [...] Read more.

This work describes a multisensing wearable platform for monitoring biomarkers in sweat during the practice of exercise. Five electrochemical sensors for pH, potassium, sodium, chloride, and lactate were implemented in a flexible patch approach, together with a paper microfluidic component, to continuously measure sweat composition. The sensors are fabricated with silicon technologies: ion selective field effect transistors (ISFETs) for pH and ionic species; and a gold thin-film microelectrode for lactate. The latter includes a polymeric membrane based on an electropolymerized polypyrroled structure, where all the biocomponents required for carrying out the lactate analyses are entrapped. The flexible patch is fabricated using hybrid integration technologies, including printed pads defined on a polyimide (Kapton^®) substrate and wire bonding encapsulation of silicon chips. To fix and align the sensors to the flexible substrate, different laminated materials, such as polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), and silicone-based adhesive, were used. The first results show good performance of the sensors—ISFETS sensitivity between 54–59 mV dec⁻¹ for ion ranges in sweat from 2 to 100 mM and lactate sensor sensitivity of −135 × 102 µA M⁻¹ cm⁻² for the range of 2–50 mM. The microfluidic platform has been tested in terms of adequate sensor wettability and rapid response during the time span of exercise activity (2 h) showing excellent results. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

160 KiB

Open AccessAbstract

Wearable xAI: A Knowledge-Based Federated Learning Framework

by Sara Nasiri, Iman Nasiri and Kristof Van Laerhoven

Eng. Proc. 2021, 6(1), 79; https://doi.org/10.3390/I3S2021Dresden-10143 - 17 May 2021

Viewed by 1455

Abstract

Federated learning is a knowledge transmission and training process that occurs in turn between user models on edge devices and the training model in the central server. Due to privacy policies and concerns and heterogeneous data, this is a widespread requirement in federated [...] Read more.

Federated learning is a knowledge transmission and training process that occurs in turn between user models on edge devices and the training model in the central server. Due to privacy policies and concerns and heterogeneous data, this is a widespread requirement in federated learning applications. In this work, we use knowledge-based methods, and in particular case-based reasoning (CBR), to develop a wearable, explainable artificial intelligence (xAI) framework. CBR is a problem-solving AI approach for knowledge representation and manipulation, which considers successful solutions of past conditions that are likely to serve as candidate solutions for a requested problem. It enables federated learning when each user owns not only his/her private data, but also uniquely designed cases. New generated cases can be compared to the knowledge base and the recommendations enable the user to communicate better with the whole system. It improves users’ task performance and increases user acceptability when they need explanations to understand why and how AI algorithms arrive at these optimal solutions. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

162 KiB

Open AccessAbstract

Evaluation of the Electrochromic Response of Polypyrrole in the Presence of CO₂ in the Solution

by Vilma Ratautaite, Gintautas Bagdziunas, Ernestas Brazys, Almira Ramanaviciene and Arunas Ramanavicius

Eng. Proc. 2021, 6(1), 80; https://doi.org/10.3390/I3S2021Dresden-10128 - 17 May 2021

Viewed by 597

Abstract

The indium tin oxide (ITO)-coated glass was used as a working electrode for electrochemical deposition of conducting polymer polypyrrole (Ppy). Before polymerization, the electrode surface was additionally modified with triethoxymethylsilane (TEMS) to provide better adhesion of polypyrrole to the surface of ITO. The [...] Read more.

The indium tin oxide (ITO)-coated glass was used as a working electrode for electrochemical deposition of conducting polymer polypyrrole (Ppy). Before polymerization, the electrode surface was additionally modified with triethoxymethylsilane (TEMS) to provide better adhesion of polypyrrole to the surface of ITO. The polymerization of Ppy was performed electrochemically, regarding the previous studies. The ionic strength of the solution was supported by LiClO₄. Since the dissolved CO₂ in the solution forms weak acid and, thus, the pH of a solution can be slightly changed, the electrochromic response to the pH changes was evaluated. Britton–Robinson buffer (BRB) was used as the model system for an evaluation of the electrochromic response of polypyrrole at different pH values and concentrations of NaHCO₃, which was a source of CO₂ in the solution. For the evaluation of the electrochromic response in the presence of CO₂, the double potential step chronoamperometry method was applied and UV-Vis absorption spectra were registered. To gain insight into the charge transfer phenomenon in more detail, the cyclic voltammetry experiments at different glass/ITO_(TEMS)/Ppy electrode potential sweep rates were performed. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

188 KiB

Open AccessAbstract

Measurement of PM10 and PM2.5 Using SAW Sensors-Based Rayleigh Wave and Love Wave

by Fatima-Ezzahraa Dbibih, Meddy Vanotti, Valerie Soumann, Jean-Marc Cote, Lyes Djoumi and Virginie Blondeau-Patissier

Eng. Proc. 2021, 6(1), 81; https://doi.org/10.3390/I3S2021Dresden-10129 - 17 May 2021

Viewed by 605

Abstract

Particulate matter (PM) is reported to be dangerous and can cause respiratory and health issues. Regulations, based on PM concentration, have been implemented to limit human exposition to air pollution. An innovative system with surface acoustic wave (SAW) sensors combined with a 3 [...] Read more.

Particulate matter (PM) is reported to be dangerous and can cause respiratory and health issues. Regulations, based on PM concentration, have been implemented to limit human exposition to air pollution. An innovative system with surface acoustic wave (SAW) sensors combined with a 3 Lpm cascade impactor was developed by our team for real time mass concentration measurements. In this study, we compare the PM sensitivity of two types of SAW sensors. The first one consists of delay lines based on Rayleigh waves propagating on a Lithium Niobate Y-X 128° substrate. The second one is a based-on Love waves on AT-Quartz. Aerosols were generated from NaCl for PM2.5 and from Silicon carbide for PM10. The sensors’ responses was compared to a reference sensor based on optical measurements. The sensitivity of the Rayleigh wave-based sensor is clearly lower than the Love wave sensor for both PMs. Although less sensitive, Rayleigh wave sensors remain very promising for the development of self-cleaning sensors using RF power due to their high electromechanical factor. To check the performance of our system in real conditions, we tested the sensitivity to PM from cigarette smoke using Rayleigh SAW. The PM2.5 stage showed a phase shift while the PM10 did not respond. This result agrees with previous studies which reported that the size of particles from cigarette smoke varies between 0.1 to 1.5 µm. A good correlation between the reference sensor’s response and the phase variation of SAW sensors was obtained. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

162 KiB

Open AccessAbstract

Method and Sensory System for Determination of the Liquids Surface Tension

by Sonia Amariei, Gheorghe Gutt and Liliana Anchidin-Norocel

Eng. Proc. 2021, 6(1), 82; https://doi.org/10.3390/I3S2021Dresden-10101 - 17 May 2021

Viewed by 664

Abstract

A new method and related sensory system used to determine the surface tension (γ) of a liquid investigated based on the increase of the area (A) of a drop vibrated sinusoidally is presented. The materialization of the method consists in specific device placed [...] Read more.

A new method and related sensory system used to determine the surface tension (γ) of a liquid investigated based on the increase of the area (A) of a drop vibrated sinusoidally is presented. The materialization of the method consists in specific device placed on the table of a microscope or a stereomicroscope, both based on the principle of light reflection. A drop of the analyzed liquid deposited with a dispenser on a metal plate, vibrated electrodynamically under the action of a sinusoidal oscillation, of constant frequency and amplitude, increases its surface wetted on the metal plate with each applied sinusoidal oscillation. At each magnification of the droplet surface area, an image acquisition takes place through the optoelectronic system of the microscope or stereomicroscope, the frequency of the oscillations being strictly correlated with the acquisition frequency of the images. At a predetermined number of images/oscillations, using specific software, both the images of the droplets and the graph containing the number of pixels inside the outline of each image and the current number of vibration corresponding to that image are displayed. The surface tension is automatically expressed by the growth speed of the drops surface, speed given by the curve slope of the pixels number of the drops according to the current number of the oscillation. A collateral application is the possibility of using the sensory system and specialized software for rapid determination of solutions concentration, measuring the surface tension using the Szyszkowski relation. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

194 KiB

Open AccessAbstract

A Low-Cost Visible Light Communications System Based on Organic Photodetection for Transmitting Images

by Pablo Corral, Fernando Rodríguez-Mas, José Luis Alonso, Juan Carlos Ferrer and Susana Fernández de Ávila

Eng. Proc. 2021, 6(1), 85; https://doi.org/10.3390/I3S2021Dresden-10116 - 17 May 2021

Viewed by 590

Abstract

In Visible Light Communication (VLC) Systems, data are transmitted by modulating light from an illumination source, that could be an ordinary lamp or light-emitting diodes (LEDs). Photovoltaic cells based on massive heterojunctions of semiconductor polymers have focused the attention of researchers due to [...] Read more.

In Visible Light Communication (VLC) Systems, data are transmitted by modulating light from an illumination source, that could be an ordinary lamp or light-emitting diodes (LEDs). Photovoltaic cells based on massive heterojunctions of semiconductor polymers have focused the attention of researchers due to several potential advantages over their inorganic counterparts, such as simplicity, low cost and the ability to process large area devices even on flexible substrates. In this paper, we use commercial LEDs in transmission and organic photodetectors (OPD) based on poly(3-hexylthiophene) (P3HT) and a phenyl-C61-butyric acid methyl ester (PCBM) blend used as active layer in reception. We have fabricated and characterized the I-V curve and the Bit Error Rate (BER) response of the OPD using low cost processing techniques and we have used an Atmel 8-bit microcontroller in order to control the electronics to transmit and modulate the signal. Finally, in this work, we have developed and characterized organic photodetectors in a low cost visible light communications system capable of transmitting an image file in real-time, as a proof of concept that is cost effective, since the whole system was implemented using low cost components. You can find more information in the supplementary materials. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

148 KiB

Open AccessAbstract

Optoelectronic Sensory System for Raman Spectromicroscopes

by Gheorghe Gutt, Valentin Popa and Mihai Dimian

Eng. Proc. 2021, 6(1), 87; https://doi.org/10.3390/I3S2021Dresden-10107 - 17 May 2021

Viewed by 550

Abstract

In order to obtain a high microscopic and spectral resolution, both for the microscopic study and for the spectrometric analysis carried out simultaneously at the same area of the sample, an adaptive optoelectronic system for Raman spectromicroscopes with a near-infrared excitation light source [...] Read more.

In order to obtain a high microscopic and spectral resolution, both for the microscopic study and for the spectrometric analysis carried out simultaneously at the same area of the sample, an adaptive optoelectronic system for Raman spectromicroscopes with a near-infrared excitation light source is designed. The current system and its working mode have a major disadvantage due to the fact that the sample is moved several times to and from the focusing lens of the excitation radiation in the search for the focal point in order to ensure the maximum spectral resolution. In this process, the peak height for the Stokes spectrum is monitored and the focal point is considered achieved when the peak height reaches its maximum. Due to the high energy density in a focal point, repeated searches of this point may lead to the modification of the chemical composition of the investigated material and, in some cases, even to the decomposition of some of its components. This paper presents an advanced technical solution that allows the microscopic study of the sample in the focal point of the visible spectrum, as well as the rapid and automatic search of the focal point in the Raman spectral analysis, at a wavelength of 1064 nm in the near-infrared spectral domain without thermally affecting the sample. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

177 KiB

Open AccessAbstract

Low Power Multisensors for Selective Gas Detection

by Virginie Martini, Khalifa Aguir, Bruno Lawson and Marc Bendahan

Eng. Proc. 2021, 6(1), 89; https://doi.org/10.3390/I3S2021Dresden-10151 - 17 May 2021

Viewed by 508

Abstract

The aim of this work is the realization of a generic gas multisensor device based on MOX sensitive layer. We designed and modeled a novel detection system with several heating zones associated with three sensors supported on a membrane with a few micrometers [...] Read more.

The aim of this work is the realization of a generic gas multisensor device based on MOX sensitive layer. We designed and modeled a novel detection system with several heating zones associated with three sensors supported on a membrane with a few micrometers of thickness. The design was optimized to overcome the problems of response stability and selectivity and to reduce power consumption. The heat repartition and the power consumption in relation to the membrane thickness were studied by finite element simulations. The results show that a membrane thickness of 4 µm decreases the heater temperature by more than 100 K versus 2 µm thickness. Ethanol detection performances were studied. The thermoelectrical characterization concluded that the three detection areas can be heated at 533 K with a power of 53 mW. One sensor was tested in ethanol. The sensor response in 1 ppm and 100 ppm of ethanol in a 50% relative humidity atmosphere was 1.4 and 9.2, respectively. We demonstrated that this detection device can detect ethanol with high sensitivity and stability in dry and humid air with reduced power consumption resulting in 18 mW per sensor. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

163 KiB

Open AccessAbstract

Evaluating Techniques for Joining Piezo-Electric Elements on Test Structures for Performing Vibration-Based Measurement Methods

by Christian Gundlach, Stefan Meyer, Chris Hopmann, Klaus Dilger and Sven Hartwig

Eng. Proc. 2021, 6(1), 91; https://doi.org/10.3390/I3S2021Dresden-10078 - 17 May 2021

Viewed by 586

Abstract

When performing vibration-based measurement techniques, e.g., for structural health monitoring, piezo-electric elements are often used as the sensor and/or actuator part due to their durability. The connection between the piezo-electric element and the test structure plays a decisive role in the quality of [...] Read more.

When performing vibration-based measurement techniques, e.g., for structural health monitoring, piezo-electric elements are often used as the sensor and/or actuator part due to their durability. The connection between the piezo-electric element and the test structure plays a decisive role in the quality of the results obtained in the vibration-based measurement process. In addition to stable and mode-independent vibration transmission, further requirements such as reversibility or temperature resistance can be imposed depending on the application. In many preliminary studies, bonding by means of a two-component epoxy resin was practically and simulatively validated for a large amount of use cases. Nevertheless, the limited reversibility and the preparation time of the adhesion process can limit the flexibility of the vibration-based measurement method. The aim of this work is to evaluate different joining technologies of piezo-electric elements on metal and polymer substrates, especially with respect to reversibility. Different techniques for joining piezo elements are collected, considering previous work as well as newly developed approaches within the scope of the work. In the next step, frequency spectra of simple circular blanks are obtained using an EMI setup of piezo elements joined to the blanks with the appropriate joining technique. Joining by means of a two-component epoxy is considered as the reference method. All joining techniques are evaluated, especially based on the degree of reversibility, transmission quality, effort for implementation and durability, in comparison to the reference method. Finally, recommendations regarding the proper joining technique for different experimental conditions are given based on the results. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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Jump to: Research

3 pages, 355 KiB

Open AccessProceeding Paper

Study of the Effect of Bending Deformation on the Performance of Flexible Polymer Layered Humidity Sensor

by Katerina Lazarova, Silvia Bozhilova, Sijka Ivanova, Darinka Christova and Tsvetanka Babeva

Eng. Proc. 2021, 6(1), 6; https://doi.org/10.3390/I3S2021Dresden-10069 - 17 May 2021

Viewed by 838

Abstract

Humidity-sensitive polymer, namely poly(vinyl alcohol-co-vinyl acetal), was deposited on a flexible poly(ethylene terephthalate) (PET) substrate pre-covered with a sputtered Au:Pd thin layer in order to develop an optical flexible humidity sensor. The spin-coating method was applied for the thin polymer film [...] Read more.

Humidity-sensitive polymer, namely poly(vinyl alcohol-co-vinyl acetal), was deposited on a flexible poly(ethylene terephthalate) (PET) substrate pre-covered with a sputtered Au:Pd thin layer in order to develop an optical flexible humidity sensor. The spin-coating method was applied for the thin polymer film deposition. The optical and sensing properties of the device were studied after repeated bending deformation in the range of 25−1000 times. Transmittance measurements at different levels of relative humidity were conducted in order to examine the sensing properties of the probed flexible sample. The influence of the number of bending deformations on the performance of the sensor is studied, and the possibility for its successful application is demonstrated and discussed. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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4 pages, 705 KiB

Open AccessProceeding Paper

A Soft Pneumatic Actuator with Integrated Deformation Sensing Elements Produced Exclusively with Extrusion Based Additive Manufacturing

by Antonia Georgopoulou, Lukas Egloff, Bram Vanderborght and Frank Clemens

Eng. Proc. 2021, 6(1), 11; https://doi.org/10.3390/I3S2021Dresden-10097 - 17 May 2021

Cited by 1 | Viewed by 1045

Abstract

In recent years, soft pneumatic actuators have come into the spotlight because of their simple control and the wide range of complex motions. To monitor the deformation of soft robotic systems, elastomer-based sensors are being used. However, the embedding of sensors into soft [...] Read more.

In recent years, soft pneumatic actuators have come into the spotlight because of their simple control and the wide range of complex motions. To monitor the deformation of soft robotic systems, elastomer-based sensors are being used. However, the embedding of sensors into soft actuator modules by polymer casting is time consuming and difficult to upscale. In this study, it is shown how a pneumatic bending actuator with an integrated sensing element can be produced using an extrusion-based additive manufacturing method, e.g., fused deposition modeling (FDM). The advantage of FDM against direct printing or robocasting is the significantly higher resolution and the ability to print large objectives in a short amount of time. New, commercial launched, pellet-based FDM printers are able to 3D print thermoplastic elastomers of low shore hardness that are required for soft robotic applications, to avoid high pressure for activation. A soft pneumatic actuator with the in situ integrated piezoresistive sensor element was successfully printed using a commercial styrene-based thermoplastic elastomer (TPS) and a developed TPS/carbon black (CB) sensor composite. It has been demonstrated that the integrated sensing elements could monitor the deformation of the pneumatic soft robotic actuator. The findings of this study contribute to extending the applicability of additive manufacturing for integrated soft sensors in large soft robotic systems. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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4 pages, 1353 KiB

Open AccessProceeding Paper

Non-Monotonic Sensor Behavior of Carbon Particle-Filled Textile Strain Sensors

by Johannes Mersch, Henriette Probst, Andreas Nocke, Chokri Cherif and Gerald Gerlach

Eng. Proc. 2021, 6(1), 13; https://doi.org/10.3390/I3S2021Dresden-10140 - 17 May 2021

Cited by 1 | Viewed by 880

Abstract

Carbon particle-filled elastomers are a widely researched option to be used as piezoresistive strain sensors for soft robotics or human motion monitoring. Therefore, various polymers can be compounded with carbon black (CB), carbon nanotubes (CNT) or graphene. However, in many studies, the electrical [...] Read more.

Carbon particle-filled elastomers are a widely researched option to be used as piezoresistive strain sensors for soft robotics or human motion monitoring. Therefore, various polymers can be compounded with carbon black (CB), carbon nanotubes (CNT) or graphene. However, in many studies, the electrical resistance strain response of the carbon particle-filled elastomers is non-monotonic in dynamic evaluation scenarios. The non-monotonic material behavior is also called shoulder phenomenon or secondary peak. Until today, the underlying cause is not sufficiently well understood. In this study, several influencing test parameters on the shoulder phenomena are explored, such as strain level, strain rate and strain history. Moreover, material parameters such as CNT content and anisotropy are varied in melt-spun CNT filled thermoplastic polyurethane (TPU) filament yarns, and their non-monotonic sensor response is evaluated. Additionally, a theoretical concept for the underlying mechanism and thereupon-based model is presented. An equivalent circuit model is used, which incorporates the visco-elastic properties and the characteristic of the percolation network formed by the conductive filler material. The simulation results are in good agreement when compared to the experimental results. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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4 pages, 510 KiB

Open AccessProceeding Paper

Disclosing the Sensitivity and Selectivity of Metal Oxide/Graphene Oxide-Based Chemoresistors towards VOCs

by Eleonora Pargoletti, Antonio Tricoli, Mariangela Longhi, Gian Luca Chiarello and Giuseppe Cappelletti

Eng. Proc. 2021, 6(1), 18; https://doi.org/10.3390/I3S2021Dresden-10163 - 19 May 2021

Cited by 1 | Viewed by 741

Abstract

Nowadays, gas sensors play a vital role in a plethora of applications. However, there are still some important shortcomings, such as the scarce selectivity and sensitivity, especially at low operating temperatures. Herein, we report the successful sensing achieved by tailoring the chemoresistive materials [...] Read more.

Nowadays, gas sensors play a vital role in a plethora of applications. However, there are still some important shortcomings, such as the scarce selectivity and sensitivity, especially at low operating temperatures. Herein, we report the successful sensing achieved by tailoring the chemoresistive materials comprised of graphene oxide (GO) sheets well-integrated in a three-dimensional network of n-type metal oxide semiconductors (MOS). Thanks to the synergistic effect between GO and MOS under UV light, we obtained a very good sensitivity (down to 100 ppb) towards different volatile organic compounds (VOCs, i.e., ethanol, acetone, ethylbenzene, toluene) even at room temperature. Moreover, the best performing sensor (SnO₂/GO 32:1) resulted in being highly selective towards polar compounds, such as acetone. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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5 pages, 981 KiB

Open AccessProceeding Paper

Fix-Wavelength Multi-Analyte Detection with Serial SOI Ring Resonators

by Laura Kasper, Abbas Zein Al-Din, Jürgen Bruns, Rudolf Volkmer and Klaus Petermann

Eng. Proc. 2021, 6(1), 22; https://doi.org/10.3390/I3S2021Dresden-10108 - 17 May 2021

Viewed by 845

Abstract

We present a method for the read-out of five serially arranged SOI ring resonator-based biosensors at a speed of 3 Hz/sensor and a fixed wavelength of 1550 nm. The system uses the high thermo-optical coefficient of silicon by applying AC voltages to periodically [...] Read more.

We present a method for the read-out of five serially arranged SOI ring resonator-based biosensors at a speed of 3 Hz/sensor and a fixed wavelength of 1550 nm. The system uses the high thermo-optical coefficient of silicon by applying AC voltages to periodically heat up electrodes adjacent to each sensor. A time-division multiplex scheme allows the allocation of the measured optical output from the mutual spectrum to each specific resonator. We demonstrate our system by immobilizing two different antibodies (biotin and a hexa-His-peptide) at the surface of selected resonators and successfully showing the selective binding characteristics of analyte probing in a microfluidics supported experiments. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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615 KiB

Open AccessProceeding Paper

Development of Enzymatic Biosensors to Detect Biocide Disinfectants to Strengthen Self-Monitoring in Industry

by Valérie Gaudin and Christophe Soumet

Eng. Proc. 2021, 6(1), 36; https://doi.org/10.3390/I3S2021Dresden-10077 - 17 May 2021

Viewed by 955

Abstract

Biocide disinfectants are used in agro-food industries in order to limit the development of pathogens present in environment or on surfaces in contact with food for human or animal consumption. Biocide residues remaining on food surfaces may constitute a toxicological risk for the [...] Read more.

Biocide disinfectants are used in agro-food industries in order to limit the development of pathogens present in environment or on surfaces in contact with food for human or animal consumption. Biocide residues remaining on food surfaces may constitute a toxicological risk for the consumer. Very little feedback from the field on the rates of biocide residues in the industry exist due to a lack of simple, fast and responsive self-checking methods. The development of biosensors for the detection of biocide disinfectants represents a promising way to explore this, but most of this research remains limited. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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1349 KiB

Open AccessProceeding Paper

Theory and Modeling of Eddy Current Type Inductive Conductivity Sensors

by Julius Harms and Thorsten A. Kern

Eng. Proc. 2021, 6(1), 37; https://doi.org/10.3390/I3S2021Dresden-10103 - 17 May 2021

Viewed by 2267

Abstract

While transformer-type conductivity sensors are the usual type of inductive sensors, this paper describes the theory behind less used eddy current sensors. This type of sensor measures the conductivity of a liquid by inducing eddy currents and observing the effect on the sensor [...] Read more.

While transformer-type conductivity sensors are the usual type of inductive sensors, this paper describes the theory behind less used eddy current sensors. This type of sensor measures the conductivity of a liquid by inducing eddy currents and observing the effect on the sensor coil, which allows a simpler sensor design and promises a cost advantage in implementation. A novel model description is derived from the Maxwell equations and implemented by an equivalent RLC circuit. The designed model is validated by comparisons with experimental observations and FEM simulations. The result leads to a better understanding of the physical effects of the sensor and the influencing parameters for future sensor developments. The aim is to provide starting points for further sensor development of low-cost inductive conductivity sensors. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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1484 KiB

Open AccessProceeding Paper

Photonic Biosensor for Label-Free Detection Based on Photonic Nanostructures on Si-Waveguide Ring Resonator

by Hoang Anh Truong, Yugang Shang, Shunsuke Abe, Nobuyuki Matsuda and Hirohito Yamada

Eng. Proc. 2021, 6(1), 39; https://doi.org/10.3390/I3S2021Dresden-10158 - 19 May 2021

Cited by 2 | Viewed by 1020

Abstract

A new structure of a micro-ring resonator for label-free biosensing is proposed. The structure includes sidewall-grating Si waveguide and periodical side-blocks that can enhance the light–matter interaction. From the electromagnetic simulations, the proposed structure exhibits a four-fold improvement in terms of sensitivity compared [...] Read more.

A new structure of a micro-ring resonator for label-free biosensing is proposed. The structure includes sidewall-grating Si waveguide and periodical side-blocks that can enhance the light–matter interaction. From the electromagnetic simulations, the proposed structure exhibits a four-fold improvement in terms of sensitivity compared with the conventional structure. Moreover, the quality factor of the proposed structure is not degraded from that of the conventional structure. The improved sensitivity is promising for the detection of nanoparticles that can be applied to the environmental field and clinical diagnostics. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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912 KiB

Open AccessProceeding Paper

Design and Simulations of 2D Planar Antenna for Dielectric Characterization of Biological Samples

by Urvashi, Zeeshan Saifi, Mridul Kumar and Soami Daya Krishnananda

Eng. Proc. 2021, 6(1), 42; https://doi.org/10.3390/I3S2021Dresden-10079 - 17 May 2021

Viewed by 1214

Abstract

The dielectric parameters help in understanding the structural, compositional and functional analysis of biological samples. These parameters have also been widely adopted in biomedical and therapeutic fields. In the microwave region, these parameters attract interest because the principal constituent of most biological cells [...] Read more.

The dielectric parameters help in understanding the structural, compositional and functional analysis of biological samples. These parameters have also been widely adopted in biomedical and therapeutic fields. In the microwave region, these parameters attract interest because the principal constituent of most biological cells is water. Therefore, it is difficult to isolate the dielectric response of water present in a biological composite. Therefore, the technique with enhanced sensitivity is essential for measuring the dielectric properties of biological samples. In this paper, we report the design and CST simulation of a 2D-planar patch type antenna with capacitive coupling introduced by dividing the patch through a gap. The aforementioned design further improves the antenna’s sensitivity to the dielectric properties of materials. Here, we simulated ten biological phantoms by measuring the shift in resonant frequency and return loss. Our results were identical when loading samples on either of the two introduced patches. These results suggest the repeatability and further improvements in a cavity-based technique where the sample localization is an important issue. Moreover, we analytically studied the dependency of gain and directivity of the antenna on the capacitive coupling, which plays a major role in the antenna’s sensitivity to dielectric characterization. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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718 KiB

Open AccessProceeding Paper

LATE-PCR for LoC Molecular Diagnostics Devices and Its Application to the Sensitive Detection of SARS-CoV-2

by Dimitrios Karadimas and George Tsekenis

Eng. Proc. 2021, 6(1), 43; https://doi.org/10.3390/I3S2021Dresden-10076 - 17 May 2021

Viewed by 1490

Abstract

The emergence of the novel coronavirus, SARS-CoV-2, has highlighted the need for rapid, accurate, and point-of-care diagnostic testing. Lab-on-a-Chip (LoC) devices offer the possibility to run such tests at a low cost, while at the same time permitting the multiplexed detection of several [...] Read more.

The emergence of the novel coronavirus, SARS-CoV-2, has highlighted the need for rapid, accurate, and point-of-care diagnostic testing. Lab-on-a-Chip (LoC) devices offer the possibility to run such tests at a low cost, while at the same time permitting the multiplexed detection of several viruses when coupled with microarray detection of the amplified products. Herein, we report the development of a protocol for the qualitative detection of SARS-CoV-2, through the design of appropriate primers that target the evolutionary conserved regions of the virus. The proposed protocol relies on an improved version of asymmetric RT-PCR, the linear-after-the-exponential (LATE)-PCR that uses primers that are deliberately designed for use at unequal concentrations. As a result, LATE-PCR exhibits similar efficiency to symmetric PCR, while promoting accumulation of single-stranded products that can subsequently hybridize to a single-strand DNA probe-spotted microarray. The performance of the developed LATE-PCR protocol was compared to that of symmetric RT-PCR, and validated with the use of artificial viral RNA and nasopharyngeal swab samples from real patients. Furthermore, and in order to illustrate its potential for integration into a biosensor platform, the amplicons were allowed to hybridize with probes that were covalently immobilized onto commercially available functionalized glass, without the need for heat denaturation. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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758 KiB

Open AccessProceeding Paper

Evaluation System of Open Platform Cameras for Bio-Imaging

by Ji-Yeon Baek, Jong-Dae Kim, Chan-Young Park, Yu-Seop Kim and Ji-Soo Hwang

Eng. Proc. 2021, 6(1), 44; https://doi.org/10.3390/I3S2021Dresden-10093 - 17 May 2021

Cited by 1 | Viewed by 872

Abstract

With the development of smartphones, cameras based on ultra-small, high-definition, and open platforms have been mass-produced. In this paper, we outline how we built an emulation system to verify the bio-imaging performance of bulky and expensive high-performance cameras previously used in bio-imaging devices, [...] Read more.

With the development of smartphones, cameras based on ultra-small, high-definition, and open platforms have been mass-produced. In this paper, we outline how we built an emulation system to verify the bio-imaging performance of bulky and expensive high-performance cameras previously used in bio-imaging devices, and various smartphone cameras. Four types of camera were tested in the emulator, and the gel image analysis results were compared by selecting three cameras with more linear changes in slope, which matched the performance evaluation in the emulator. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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1378 KiB

Open AccessProceeding Paper

Computer Support of Analysis of Optical Spectra Measurements

by Sandra Pawłowska

Eng. Proc. 2021, 6(1), 51; https://doi.org/10.3390/I3S2021Dresden-10150 - 17 May 2021

Cited by 1 | Viewed by 868

Abstract

The verification of measurement errors has a big impact on the assessment of the accuracy of conducted measurements and obtained results. In many cases, computer simulation results are compared with measurement results in order to evaluate measurement errors. The purpose of our research [...] Read more.

The verification of measurement errors has a big impact on the assessment of the accuracy of conducted measurements and obtained results. In many cases, computer simulation results are compared with measurement results in order to evaluate measurement errors. The purpose of our research was to check the accuracy of measurements made with a Fabry–Perot interferometer working in the transmission mode. In the measurement setup, a 1310 nm superluminescent diode light source, single-mode optical fibers and an optical spectrum analyzer were used. The influence of the length of the resonating cavity and refractive index on the envelope of the optical spectrum was investigated. A program was created that models the envelope of the optical spectrum on the basis of the length of the resonating cavity, the refractive index and the light source output spectral characteristic, which in simulation was assumed to have the shape of Gaussian distribution. After the simulation the program compares the simulated and measured optical spectrum. The comparison of simulated and measured optical spectra proved to be challenging due to the shift in the position of the central peak between the simulated and measured optical spectrum. There are two ways to perform model fitting: by adjusting the position of central peaks or minimums next to the central peak. It was observed that the second solution was more optimal and was implemented in the program. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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12549 KiB

Open AccessProceeding Paper

Uncertainty Analysis for Low-Cost Transformer-Type Inductive Conductivity Sensors

by Yiğithan Kandur, Julius Harms and Thorsten A. Kern

Eng. Proc. 2021, 6(1), 52; https://doi.org/10.3390/I3S2021Dresden-10145 - 17 May 2021

Viewed by 1001

Abstract

Transformer-type inductive conductivity sensors (TICS) are the industry standard for long-term conductivity measurement in fluids. This paper analyzes the potential of TICS as a low-cost alternative to the cost-effective type of conductivity cells by an implementation with reduced complexity. Sensor characteristics and performance [...] Read more.

Transformer-type inductive conductivity sensors (TICS) are the industry standard for long-term conductivity measurement in fluids. This paper analyzes the potential of TICS as a low-cost alternative to the cost-effective type of conductivity cells by an implementation with reduced complexity. Sensor characteristics and performance in comparison to high precision sensor are described in the study. Linearity and hysteresis error in measurement, reproducibility and permeability influenced by the temperature change are quantified through the experiments. The results were interpreted in regard to core material, geometric properties and noise shielding. The study presented in this paper provides a better understanding of performance and uncertainty characteristics in order to improve the design of low-cost transformer-type inductive conductivity sensors. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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2918 KiB

Open AccessProceeding Paper

Failure Analysis of Wire Bonding on Strain Gauge Contact Pads Using FIB, SEM, and Elemental Mapping

by Muhammad Talal Asghar, Thomas Frank and Frank Schwierz

Eng. Proc. 2021, 6(1), 53; https://doi.org/10.3390/I3S2021Dresden-10142 - 17 May 2021

Cited by 1 | Viewed by 1316

Abstract

Stacks consisting of titanium, platinum, and gold layers constitute a popular metallization system for the bond pads of semiconductor chips. Wire bonding on such layer stacks at different temperatures has extensively been investigated in the past. However, reliable information on the bondability of [...] Read more.

Stacks consisting of titanium, platinum, and gold layers constitute a popular metallization system for the bond pads of semiconductor chips. Wire bonding on such layer stacks at different temperatures has extensively been investigated in the past. However, reliable information on the bondability of this metallization system after a high-temperature sintering process is still missing. When performing wire bonding after pressure sintering (at, e.g., 875 °C), bonding failures may occur that must be identified and analyzed. In the present study, a focused ion beam (FIB), scanning electron microscopy (SEM), and elemental mapping are utilized to characterize the root cause of failure. As a probable root cause, the infusion of metallization layers is found which causes an agglomerate formation at the interface of approximately 2 μm height difference on strain gauge contact pads and possibly an inhomogeneous mixing of layers as a consequence of the high-temperature sintering process. Potential treatment to tackle this agglomeration with the removal of the above-mentioned height difference during the process of contact pad structuring and alternative electrical interconnect methodologies are hereby suggested in this paper. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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1642 KiB

Open AccessProceeding Paper

Design and Potential Analysis of an Eddy Current Sensor for Inductive Conductivity Measurement in Fluids

by Julius Harms and Thorsten A. Kern

Eng. Proc. 2021, 6(1), 54; https://doi.org/10.3390/I3S2021Dresden-10160 - 19 May 2021

Viewed by 1397

Abstract

In the scope of this paper, a first exemplary eddy current sensor for seawater conductivity measurement is developed, based on the derived sensor theory of a previous work. By high-frequency excitation, eddy currents are induced in the fluid and are counter-fields measured with [...] Read more.

In the scope of this paper, a first exemplary eddy current sensor for seawater conductivity measurement is developed, based on the derived sensor theory of a previous work. By high-frequency excitation, eddy currents are induced in the fluid and are counter-fields measured with a sensing coil. The coil’s resonance point is used for amplification. The developed prototype is analyzed based on a derived transfer function and FEM simulations. The theory is validated using a prototype implementation. With conducted experiments on a sensor test bench, the characteristics are confirmed and disturbances identified. It is shown that frequencies exist where temperature influence is minimal. This work gives a perspective for a novel sensor to allow seawater conductivity measurement. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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380 KiB

Open AccessProceeding Paper

Effect of Milling Time on the Sensing Properties of Fly Ash Zeolite Composite Thin Films

by Katerina Lazarova, Silviya Boycheva, Marina Vasileva, Denitza Zgureva and Tsvetanka Babeva

Eng. Proc. 2021, 6(1), 55; https://doi.org/10.3390/I3S2021Dresden-10068 - 17 May 2021

Viewed by 761

Abstract

Thin films, consisting of a sol–gel Nb₂O₅ matrix doped with zeolite Na-X synthesized from fly ash through ultrasonic-assisted double-stage fusion-hydrothermal alkaline activation, were deposited by the spin-coating method. In order to improve the optical quality and sensing properties of the [...] Read more.

Thin films, consisting of a sol–gel Nb₂O₅ matrix doped with zeolite Na-X synthesized from fly ash through ultrasonic-assisted double-stage fusion-hydrothermal alkaline activation, were deposited by the spin-coating method. In order to improve the optical quality and sensing properties of the thin films, zeolites were wet milled for 60, 120 and 540 s prior to incorporation in the film. The liquid adsorption ability of thin films was tested by measuring the reflectance spectra prior to and after exposure to liquid acetone and the change in the reflection coefficient ∆R of the films was calculated. The influence of milling time of zeolites on the sensing and optical properties of the films was studied. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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1203 KiB

Open AccessProceeding Paper

Tactile Sensor Analysis during Early Stages of Manipulation for Single Grasp Identification of Daily Objects

by Vinicius Prado da Fonseca

Eng. Proc. 2021, 6(1), 56; https://doi.org/10.3390/I3S2021Dresden-10091 - 17 May 2021

Viewed by 877

Abstract

Dexterous robotic manipulation in unstructured environments is still challenging, despite the increasing number of robots entering human settings each day. Even though robotic manipulation provides complete solutions in factories and industries, it still lacks essential techniques, displaying clumsy or limited operation in unstructured [...] Read more.

Dexterous robotic manipulation in unstructured environments is still challenging, despite the increasing number of robots entering human settings each day. Even though robotic manipulation provides complete solutions in factories and industries, it still lacks essential techniques, displaying clumsy or limited operation in unstructured environments. Daily objects typically aim at the human hand, and the human somatosensory system is responsible for solving all the complex calculations required for dexterous manipulations in unstructured settings. Borrowing concepts of the human visuotactile system can improve dexterous manipulation and increase robotics usage in unstructured environments. In humans, required finger and wrist joint adjustments occur after fast identification of the object in the initial stages of manipulation. Fast object identification during those phases may increase robotic dexterous manipulation performance. The present paper explores human-inspired concepts such as haptic glance to develop robotic single-grasp object identification. This concept can assist early phases of robotic manipulation, helping automated decision-making, such as type of grasp and joint position, during manipulation tasks. The main stages developed here are detecting sensor activation and sample collection using signal-to-noise and z-score filtering on tactile data. This procedure automates touch detection and reduces the sensor space for classification. Experiments on a daily objects dataset presented compelling results that will assist in the later stages of the early phases of robotic grasping. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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376 KiB

Open AccessProceeding Paper

Low-Cost WASN for Real-Time Soundmap Generation

by Gerardo José Ginovart-Panisello, Ester Vidaña-Vila, Selene Caro-Via, Carme Martínez-Suquía, Marc Freixes and Rosa Ma Alsina-Pagès

Eng. Proc. 2021, 6(1), 57; https://doi.org/10.3390/I3S2021Dresden-10162 - 19 May 2021

Cited by 2 | Viewed by 940

Abstract

Recent advances in technology have enabled the development of affordable low-cost acoustic monitoring systems, as a response of several fields of application that require a close acoustic analysis in real-time: road traffic noise in crowded cities, biodiversity conservation in natural parks, behavioural tracking [...] Read more.

Recent advances in technology have enabled the development of affordable low-cost acoustic monitoring systems, as a response of several fields of application that require a close acoustic analysis in real-time: road traffic noise in crowded cities, biodiversity conservation in natural parks, behavioural tracking in the elderly living alone and even surveillance in public places for safety reasons. This paper presents a low-cost wireless acoustic sensor network developed to gather acoustic data to build a 24/7 real-time soundmap. Each node of the network comprises an omnidirectional microphone and a computation unit, which processes acoustic information locally to obtain nonsensitive data (i.e., equivalent continuous loudness levels or acoustic event labels) that are sent to a cloud server. Moreover, it has also been studied the placement of the acoustic sensors in a real scenario, following acoustics criteria. The ultimate goal of the deployed system is to enable the following functions: (i) to measure the Leq in real-time in a predefined window, (ii) to identify changing patterns in the previous measurements so that anomalous situations can be detected and (iii) to prevent and attend potential irregular situations. The proposed network aims to encourage the use of real-time non-invasive devices to obtain behavioural and environmental information, in order to take decisions in real-time. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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556 KiB

Open AccessProceeding Paper

Recognizing Eating Activities in Free-Living Environment Using Consumer Wearable Devices

by Lauriane Bertrand, Nathan Cleyet-Marrel and Zilu Liang

Eng. Proc. 2021, 6(1), 58; https://doi.org/10.3390/I3S2021Dresden-10141 - 17 May 2021

Cited by 3 | Viewed by 899

Abstract

The study of eating behavior has become increasingly important due to the alarming high prevalence of lifestyle-related chronic diseases. In this study, we investigated the feasibility of automatic detection of eating events using affordable consumer wearable devices, including Fitbit wristbands, Mi Bands, and [...] Read more.

The study of eating behavior has become increasingly important due to the alarming high prevalence of lifestyle-related chronic diseases. In this study, we investigated the feasibility of automatic detection of eating events using affordable consumer wearable devices, including Fitbit wristbands, Mi Bands, and the FreeStyle Libre continuous glucose monitor (CGM). Random forest and XGBoost were applied to develop binary classifiers for distinguishing eating and non-eating events. Our results showed that the proposed method can recognize eating events with an average sensitivity of up to 71%. The classifier using random forest with SMOTE resampling exhibited the best overall performance. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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2818 KiB

Open AccessProceeding Paper

Cost-Effective Multiplex Real-Time PCR Chip System Using Open Platform Camera

by Sung-Hun Yun, Ji-Sung Park, Seul-Bit-Na Koo, Chan-Young Park, Yu-Seop Kim and Jong-Dae Kim

Eng. Proc. 2021, 6(1), 59; https://doi.org/10.3390/I3S2021Dresden-10071 - 17 May 2021

Viewed by 963

Abstract

This paper proposes a cost-effective real-time multiplexed polymerase chain reaction (PCR) chip system for point-of-care (POC) testing. In the proposed system, nucleic acid amplification is performed in a reaction chamber built on a printed-circuit-board (PCB) substrate with a PCB pattern heater and a [...] Read more.

This paper proposes a cost-effective real-time multiplexed polymerase chain reaction (PCR) chip system for point-of-care (POC) testing. In the proposed system, nucleic acid amplification is performed in a reaction chamber built on a printed-circuit-board (PCB) substrate with a PCB pattern heater and a thermistor. Fluorescence can be detected through the transparent plastic on the other side of the substrate. Open platform cameras were used for miniaturization and cost-effectiveness. We also used simple and cost-effective oblique lighting to stimulate fluorescence. Response performance was investigated by observing the change in the average brightness of the chamber images with various reference dye concentrations. In addition, we investigated the interference properties between different colors by measuring the fluorescence response for each dye concentration mixed with the maximum concentration of the different dyes. Quantitative performance was validated using standard DNA solutions. Experimental results show that the proposed system is suitable for POC real-time multi-PCR systems. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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505 KiB

Open AccessProceeding Paper

System Architecture for IIoT-Based POC Molecular Diagnostic Device

by Byeong-Heon Kil, Ji-Seong Park, Chan-Young Park, Yu-Seop Kim and Jong-Dae Kim

Eng. Proc. 2021, 6(1), 60; https://doi.org/10.3390/I3S2021Dresden-10147 - 17 May 2021

Cited by 1 | Viewed by 851

Abstract

In this paper, we investigate an efficient structure for a point-of-care (POC) molecular diagnostic system based on the industrial Internet of things (IIoT). The target system can perform automated molecular diagnosis including DNA extraction, PCR amplification, and fluorescence detection. Samples and reagents are [...] Read more.

In this paper, we investigate an efficient structure for a point-of-care (POC) molecular diagnostic system based on the industrial Internet of things (IIoT). The target system can perform automated molecular diagnosis including DNA extraction, PCR amplification, and fluorescence detection. Samples and reagents are placed in a multi-room cartridge and loaded into the system. A rotating motor and a syringe motor control the cartridge to extract DNA from the sample. The extracted DNA is transferred to a polymerase chain reaction (PCR) chamber for DNA amplification and detection. The proposed system provides multiplexing of up to four colors. For POC molecular diagnostics, the World Health Organization demands features such as low volume, low cost, fast results, and a user-friendly interface. In this paper, we propose a system structure that can satisfy these requirements by using a PCR chip and open platform. A distributed structure is adopted for the convenience of maintenance, and a web-based GUI is adopted for the user’s convenience. We also investigated communication problems that may occur between system components. Using the proposed structure, the user can conveniently control from standard computing devices including a smartphone. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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1551 KiB

Open AccessProceeding Paper

Polymer-Modified Quartz Tuning Forks for Breath Biomarker Sensing

by Bishakha Ray, Shrut Manoj Desai, Saurabh Parmar and Suwarna Datar

Eng. Proc. 2021, 6(1), 62; https://doi.org/10.3390/I3S2021Dresden-10161 - 19 May 2021

Viewed by 810

Abstract

The change in levels of volatile organic compounds (VOC) present in exhaled breath can be indicative of bodily disorders. Detection of such low levels of VOCs can allow early detection and diagnosis of diseases. A polymer- modified Quartz Tuning Fork (QTF) is a [...] Read more.

The change in levels of volatile organic compounds (VOC) present in exhaled breath can be indicative of bodily disorders. Detection of such low levels of VOCs can allow early detection and diagnosis of diseases. A polymer- modified Quartz Tuning Fork (QTF) is a promising, cost-effective sensor that can detect a change in ppm levels of VOCs exhaled from the breath at room temperature. Acetone and acetaldehyde are biomarkers that are readily exhaled by human beings. Increased levels of these analytes can serve as indicators for toxicity or a wide array of diseases. The present work uses an array of QTFs modified separately using nanomaterials embedded in polystyrene to detect low VOC concentrations present in simulated human breath successfully. The sensor response shows a clear distinction between healthy human breath and breath spiked with varying VOC concentrations (5–400 ppm). The sensor response proves it can potentially serve as an economical and non-invasive tool for disease diagnostics. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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551 KiB

Open AccessProceeding Paper

A Washable Silver-Printed Textile Electrode for ECG Monitoring

by Abreha Bayrau Nigusse, Benny Malengier, Desalegn Alemu Mengistie and Lieva Van Langenhove

Eng. Proc. 2021, 6(1), 63; https://doi.org/10.3390/I3S2021Dresden-10139 - 17 May 2021

Cited by 1 | Viewed by 1041

Abstract

Electrocardiography (ECG) is one of the most widely used diagnostic methods to examine heart situations. This paper focuses on the development of a textile-based electrode and the study its ECG-detecting performance. We developed silver-printed textile electrodes via a the flat-screen printing of silver [...] Read more.

Electrocardiography (ECG) is one of the most widely used diagnostic methods to examine heart situations. This paper focuses on the development of a textile-based electrode and the study its ECG-detecting performance. We developed silver-printed textile electrodes via a the flat-screen printing of silver ink on knitted polyester fabric. The silver-printed PET fabric stayed reasonably conductive after washing and stretching, which makes it suitable for wearable applications. Moreover, the ECG measurements in static condition showed that the signal quality collected before and after washing was comparable with standard Ag/AgCl electrodes. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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923 KiB

Open AccessProceeding Paper

Probabilistic Analysis of the Spatio–Temporal Soil Saturation and Water Level Variability of the Pugllohuma Peatland Using Synthetic Aperture Radar Images of the Sentinel-1 Mission

by Paul David Carchipulla-Morales and Xavier Zapata-Ríos

Eng. Proc. 2021, 6(1), 64; https://doi.org/10.3390/I3S2021Dresden-10120 - 17 May 2021

Viewed by 746

Abstract

This study presents the spatio–temporal assessment of the Pugllohuma peatland’s soil saturation and water level variability. The Pugllohuma is a high elevation wetland located within the Sustainable Water Conservation Area Antisana in the northern Andes of Ecuador above 4100 m.a.s.l. This assessment provides [...] Read more.

This study presents the spatio–temporal assessment of the Pugllohuma peatland’s soil saturation and water level variability. The Pugllohuma is a high elevation wetland located within the Sustainable Water Conservation Area Antisana in the northern Andes of Ecuador above 4100 m.a.s.l. This assessment provides information of the dry and wet seasons in the Pugllohuma peatland. The temporal variability was investigated considering variables such as: atmospheric pressure, rainfall, relative humidity, air temperature, wind speed and direction records of two near meteorological stations, while the spatial variability was investigated through images of the Sentinel-1 mission from 2017 to 2019, and terrain characteristics such as: elevation and slope. Image analysis and degree of soil saturation classification were carried out using the R programming language and Google Earth Engine, and the results were published in the UI service in Google Apps Script. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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4307 KiB

Open AccessProceeding Paper

Radar Based Detection and Classification of Vulnerable Road Users

by Tetiana Lavrenko, Timo Gessler, Thomas Walter, Hubert Mantz and Michael Schlick

Eng. Proc. 2021, 6(1), 67; https://doi.org/10.3390/I3S2021Dresden-10098 - 17 May 2021

Viewed by 1257

Abstract

Radar sensors accurately detect different objects; however, the reliable classification of these objects remains challenging. In this contribution, new approaches to extracting and interpreting unique spectral features of pedestrians and cyclists are proposed. Both methods use range-Doppler maps, which contain information on the [...] Read more.

Radar sensors accurately detect different objects; however, the reliable classification of these objects remains challenging. In this contribution, new approaches to extracting and interpreting unique spectral features of pedestrians and cyclists are proposed. Both methods use range-Doppler maps, which contain information on the distance to and the velocity of a detected object. The detections originate from the local dynamic of the moving (body) parts, and therefore can be used to reconstruct a unique movement pattern, which is represented by a time dependent velocity distribution. Machine learning algorithms can also be applied to the obtained time series in order to automate the classification task. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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1040 KiB

Open AccessProceeding Paper

Increasing the Situation Awareness and Response Time of K9 Units Using a Smart Integrated Vest for the Canine Companion

by Maria Krommyda, Angelos Stamou, Nikos Mitro, Katerina Voulgary and Angelos Amditis

Eng. Proc. 2021, 6(1), 70; https://doi.org/10.3390/I3S2021Dresden-10159 - 19 May 2021

Cited by 1 | Viewed by 816

Abstract

First responders are tasked to intervene in small-scale emergencies and major natural or human-made disasters under unknown environments. They are required to operate around the clock, in situations that are life-threatening and potentially hazardous, with limited awareness of the operational situation, mission progress, [...] Read more.

First responders are tasked to intervene in small-scale emergencies and major natural or human-made disasters under unknown environments. They are required to operate around the clock, in situations that are life-threatening and potentially hazardous, with limited awareness of the operational situation, mission progress, and time sensitivity. They more often than not risk their own personal safety and well-being in order to keep civilians safe. During the most demanding and extended incidents, first responders operate under complex response operation plans that involve the collaboration of multiple disciplines and teams including K9 units. Within the context of the INGENIOUS project, a K9 vest for the canine of the unit is developed, aiming to improve their response time, enhance their situational awareness, support the collaboration between agencies, and most importantly, increase their safety during missions. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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2316 KiB

Open AccessProceeding Paper

Multiple Camera Fluorescence Detection for Real-Time PCR

by Seul-Bit-Na Koo, Hyeon-Gyu Chi, Ji-Sung Park, Jong-Dae Kim, Chan-Young Park, Yu-Seop Kim and Deuk-Ju Lee

Eng. Proc. 2021, 6(1), 71; https://doi.org/10.3390/I3S2021Dresden-10074 - 17 May 2021

Cited by 1 | Viewed by 920

Abstract

The general polymerase chain reaction (PCR) amplifies DNA and analyzes the amplification results of the quantified DNA. Recently, real-time PCR has been developed to detect DNA amplification in various ways. The conventional camera-based system is too expensive and difficult to reduce device size. [...] Read more.

The general polymerase chain reaction (PCR) amplifies DNA and analyzes the amplification results of the quantified DNA. Recently, real-time PCR has been developed to detect DNA amplification in various ways. The conventional camera-based system is too expensive and difficult to reduce device size. In this paper, we propose a low-cost, compact fluorescence detection system for real-time PCR systems using an open platform camera. To simplify the optics, four low-cost small cameras were fixedly placed, and the entire tube was divided into four quadrants to minimize the field of view. In addition, an effective image processing method was used to compensate. The proposed system measured the fluorescence detection performance on the basis of the amount of DNA using various fluorescent substances. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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590 KiB

Open AccessProceeding Paper

Development of an Enzyme-Coated Microcantilever-Based Biosensor for Specific Detection of Short-Chain Alcohols

by Alexandre Margarido, Livia Regina Manzine, Fernando M. Araujo-Moreira, Renato Vitalino Gonçalves and Paulo Sergio de Paula Herrmann

Eng. Proc. 2021, 6(1), 75; https://doi.org/10.3390/I3S2021Dresden-10175 - 21 May 2021

Cited by 1 | Viewed by 894

Abstract

This paper describes the development of a biosensor designed for the enzymatic detection of short-chain alcohols. The biorecognition element, alcohol dehydrogenase, was immobilized on self-assembled monolayers deposited on top of silicon nitride microcantilevers. The self-assembly process was performed by surface activation using 3-aminopropyltriethoxysilane, [...] Read more.

This paper describes the development of a biosensor designed for the enzymatic detection of short-chain alcohols. The biorecognition element, alcohol dehydrogenase, was immobilized on self-assembled monolayers deposited on top of silicon nitride microcantilevers. The self-assembly process was performed by surface activation using 3-aminopropyltriethoxysilane, followed by glutaraldehyde and biomolecule binding. X-ray photoelectron spectroscopy and atomic force microscopy were used. The biosensor showed a lower response time and sensibility from 0.03 to 1.2 mL/L. Its selectivity was analyzed through exposure to pure and mixed volatile solvents. Sensor sensibility was higher in the presence of short-chain alcohols and practically null involving other polar or nonpolar solvents. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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2040 KiB

Open AccessProceeding Paper

Needleless Electrospun Magnetic Carbon Nanofiber Mats for Sensor Applications

by Marah Trabelsi, Al Mamun, Michaela Klöcker and Lilia Sabantina

Eng. Proc. 2021, 6(1), 76; https://doi.org/10.3390/I3S2021Dresden-10130 - 17 May 2021

Cited by 3 | Viewed by 917

Abstract

Magnetic nanofibers can be fabricated by adding nanoparticles in polymer solution using electrospinning method. The advantages of such nanofibers include a large surface-to-volume ratio and high porosity, which makes them promising for sensing applications. In addition, carbonization of such nanofibers increases electrical conductivity. [...] Read more.

Magnetic nanofibers can be fabricated by adding nanoparticles in polymer solution using electrospinning method. The advantages of such nanofibers include a large surface-to-volume ratio and high porosity, which makes them promising for sensing applications. In addition, carbonization of such nanofibers increases electrical conductivity. In this study, the chemical and morphological properties of magnetic nanofiber mats prepared from polyacrylonitrile (PAN)/magnetite and carbonized at 500 °C, 600 °C, 800 °C, and 1000 °C were measured. Resulting surface morphologies with some agglomerations are discussed. Addition of nanoparticles increased average fiber diameter and improved dimensional stability. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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3820 KiB

Open AccessProceeding Paper

Aspects Regarding of a UGV Fire Fighting Thermal Shield

by Lucian Ștefăniță Grigore, Amado Ștefan, Ionica Oncioiu, Cristian Molder, Damian Gorgoteanu, Daniel Constantin and Răzvan-Ionuț Bălașa

Eng. Proc. 2021, 6(1), 83; https://doi.org/10.3390/I3S2021Dresden-10082 - 17 May 2021

Cited by 2 | Viewed by 1288

Abstract

This article presents aspects related to the protection (with a double shield made of stainless steel) of a robot for emergency situations against the effect of flames due to a fire. The ground robot is semi-autonomous/autonomous, with a wheeled propeller (6 × 6). [...] Read more.

This article presents aspects related to the protection (with a double shield made of stainless steel) of a robot for emergency situations against the effect of flames due to a fire. The ground robot is semi-autonomous/autonomous, with a wheeled propeller (6 × 6). The robot, designed and built at the TRL 2 level, is intended for fire investigation, monitoring, and intervention (and, in particular, for petrochemical plants). The role of the shield is to protect the equipment that is part of the robot including its controllers, sensors, communications, power supply, etc. The need to mount a thermal protection shield on the intervention robot was given by the fact that fires at petrochemical plants generate very large thermal fields and gradients which are responsible for creating blind spots. These blind spots do not allow intervention crews to see what is happening in that area. These blind spots are characterized by very high temperatures. The dynamics of these fires can be unpredictable. Therefore, to analyze the performance of the heat shield in this study we perform a numerical-experimental analysis. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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923 KiB

Open AccessProceeding Paper

The Effect of Measurement Trends in Belt Breathing Sensors

by Erik Vanegas, Raúl Igual and Inmaculada Plaza

Eng. Proc. 2021, 6(1), 84; https://doi.org/10.3390/I3S2021Dresden-10118 - 17 May 2021

Cited by 1 | Viewed by 907

Abstract

Sensors for respiratory monitoring can be classified into wearable and non-wearable systems. Wearable sensors can be worn in several positions, the chest being one of the most effective. In this paper, we have studied the performance of a new piezoresistive breathing sensing system [...] Read more.

Sensors for respiratory monitoring can be classified into wearable and non-wearable systems. Wearable sensors can be worn in several positions, the chest being one of the most effective. In this paper, we have studied the performance of a new piezoresistive breathing sensing system to be worn on the chest with a belt. One of the main problems of belt-attached sensing systems is that they present trends in measurements due to subject movements or differences in subject constitution. These trends affect sensor performance. To mitigate them, it is possible to post-process the data to remove trends in measurements, but relevant data from the respiration signal may be lost. In this study, two different detrending methods are applied to respiration signals. After conducting an experimental study with 21 subjects who breathed in different positions with a chest piezoresistive sensor attached to a belt, detrending method 2 proved to be better at improving the quality of respiration signals. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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748 KiB

Open AccessProceeding Paper

Carrier Mobility in Semiconductors at Very Low Temperatures

by Ingo Tobehn-Steinhäuser, Manfred Reiche, Matthias Schmelz, Ronny Stolz, Thomas Fröhlich and Thomas Ortlepp

Eng. Proc. 2021, 6(1), 86; https://doi.org/10.3390/I3S2021Dresden-10086 - 17 May 2021

Cited by 5 | Viewed by 2833

Abstract

Carrier mobilities and concentrations were measured for different p- and n-type silicon materials in the temperature range 0.3–300 K. Simulations show that experimentally determined carrier mobilities are best described in this temperature range by Klaassen’s model. Freeze-out reduces the carrier concentration with decreasing [...] Read more.

Carrier mobilities and concentrations were measured for different p- and n-type silicon materials in the temperature range 0.3–300 K. Simulations show that experimentally determined carrier mobilities are best described in this temperature range by Klaassen’s model. Freeze-out reduces the carrier concentration with decreasing temperature. Freeze-out, however, depends on the dopant type and initial concentration. Semi-classical calculations are useful only for temperatures above 100 K. Otherwise quantum mechanical calculations are required. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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1530 KiB

Open AccessProceeding Paper

Simulating Defects in Environmental Sensor Networks Using Stochastic Sensor Models

by Sebastian A. Schober, Cecilia Carbonelli and Robert Wille

Eng. Proc. 2021, 6(1), 88; https://doi.org/10.3390/I3S2021Dresden-10094 - 17 May 2021

Viewed by 713

Abstract

Chemiresistive gas sensors are an important tool for monitoring air quality in cities and large areas due to their low cost and low power and, hence, the ability to densely distribute them. Unfortunately, such sensor systems are prone to defects and faults over [...] Read more.

Chemiresistive gas sensors are an important tool for monitoring air quality in cities and large areas due to their low cost and low power and, hence, the ability to densely distribute them. Unfortunately, such sensor systems are prone to defects and faults over time such as sensitivity loss of the sensing material, less effective heating of the surface due to battery loss, or random output errors in the sensor electronics, which can lead to signal jumps or sensor stopping. Although these defects usually can be compensated, either algorithmically or physically, this requires an accurate screening of the entire sensor system for such defects. In order to properly develop, test, and benchmark corresponding screening algorithms, however, methods for simulating gas sensor networks and their defects are essential. In this work, we propose such a simulation method based on a stochastic sensor model for chemiresistive sensor systems. The proposed method rests on the idea of simulating the defect-causing processes directly on the sensor surface as a stochastic process and is capable of simulating various defects which can occur in low-cost sensor technologies. The work aims to show the scope and principles of the proposed simulator as well as to demonstrate its applicability using exemplary use cases. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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1994 KiB

Open AccessProceeding Paper

Towards Integrated Plasmonic Gas Sensors in the MWIR

by Andreas Tortschanoff, Jasmin Spettel, Gerald Stocker, Thang Duy Dao, Cristina Consani, Clement Fleury, Florian Dubois, Thomas Grille, Thomas Ostermann, Parviz Saeidi, Reyhaneh Jannesari, Gerald Pühringer and Bernhard Jakoby

Eng. Proc. 2021, 6(1), 90; https://doi.org/10.3390/I3S2021Dresden-10104 - 17 May 2021

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Abstract

Optical measurement approaches have proven to provide intrinsic selectivity and the sensitivity, required for the development of integrated gas sensors. In an ongoing project, we work towards a Si-photonics non-dispersive infrared gas sensor and are investigating the possibility of the incorporation of IR-plasmonic [...] Read more.

Optical measurement approaches have proven to provide intrinsic selectivity and the sensitivity, required for the development of integrated gas sensors. In an ongoing project, we work towards a Si-photonics non-dispersive infrared gas sensor and are investigating the possibility of the incorporation of IR-plasmonic materials, which could allow an increase in sensitivities and reduce the size of such sensors. Here we present the basic concept and discuss in some detail first results concerning fabrication and characterization of the plasmonic properties. Full article

(This article belongs to the Proceedings of The 8th International Symposium on Sensor Science)

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