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Mechanical and Biomedical Engineering in Paradigm
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Mechanical and Biomedical Engineering in Paradigm

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Mechanical Engineering".

Deadline for manuscript submissions: closed (31 October 2023) | Viewed by 34105

Special Issue Editor

Dr. Michal Puškár

E-Mail Website
Guest Editor
Department of Design and Transport Engineering, Faculty of Mechanical Engineering, Technical University of Košice, Letná 1/9, 040 01 Košice, Slovakia
Interests: emissions; mechanical engineering; vehicle; marine
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue is focused on all aspects related to mechanical and biomedical engineering in paradigm. Articles concerning additive manufacturing using advanced materials and biomaterials are welcome. Manuscripts dealing with the prevention, diagnostics, and treatment of COVID19 and taking into consideration engineering aspects are also very welcome. Works targeting digitization in industry and works focusing on environmental protection will be considered. We recommend that contributors submit manuscripts that correspond to one or more of the above-mentioned topics. However, other contributions not directly related to these areas but still of interest to this Special Issue will also be taken into consideration.

Assoc. Prof. Ing. Michal Puškár, PhD.
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Additive manufacturing 
  • Advanced materials
  • Biomaterials 
  • Human biomechanics 
  • COVID-19: prevention, diagnostics, and treatment from an engineering perspective 
  • Digitalization in industry
  • Engineering and protection of the environment

Published Papers (19 papers)

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Research

19 pages, 4012 KiB  
Article
Implementation of Quality Tools in Mechanical Engineering Piece Production
by Štefan Markulik, Marek Šolc and Milan Fiľo
Appl. Sci. 2024, 14(2), 944; https://doi.org/10.3390/app14020944 - 22 Jan 2024
Viewed by 684
Abstract
The world is undergoing dynamic changes. For businesses, it brings positives, but also negatives. The positive is the global market for business. The downside of the global market is the increasing competitive pressure. Large enterprises with serial production who are setting production for [...] Read more.
The world is undergoing dynamic changes. For businesses, it brings positives, but also negatives. The positive is the global market for business. The downside of the global market is the increasing competitive pressure. Large enterprises with serial production who are setting production for a longer period ahead are not so noticeable. Small companies are the most vulnerable. There are various tools or overall approaches to business management that allow them to increase work efficiency or production productivity or eliminate waste. In recent years, one can see an increase in the popularity of Lean or Six Sigma. Their contribution to businesses cannot be disputed. Most of the tools and approaches to support business management are oriented or based on the conditions of serial production. Small businesses with piece production are at a disadvantage here. It was this fact that motivated us to focus on piece production and to find space for the implementation of supporting tools that could be helpful. Our research has shown that there are tools that can be applied in the conditions of piece production. The application of the identified tools proved that the results achieved in reducing production times or increasing productivity are unmistakable. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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15 pages, 5396 KiB  
Article
Detection, Localisation and Quantification of Structural Damage Using Changes in Modal Characteristics
by Marek Páleník, Miloš Musil and Juraj Úradníček
Appl. Sci. 2023, 13(19), 10777; https://doi.org/10.3390/app131910777 - 28 Sep 2023
Viewed by 589
Abstract
The article defines and explains methods for detecting and locating damage and quantifying its extent on an example of a finite element model of a simple beam. The defined methods are based on a comparison of the decreases in the bending natural frequencies [...] Read more.
The article defines and explains methods for detecting and locating damage and quantifying its extent on an example of a finite element model of a simple beam. The defined methods are based on a comparison of the decreases in the bending natural frequencies of the nominally damaged models against the intact model. This comparison assigns natural frequency decreases to curvature of a specific mode shape, which allows creation of an analytical reference model using polynomial regression, which assigns relative natural frequency decreases to the position on the beam. The localisation method assumes that the vector of the relative natural frequency decrease ratios are unique for each position on the beam. The quantification method considers as a relevant comparative quantity, slopes of relative natural frequency decreases, as a function of damage extent. Examples of damage localisation and quantification are defined, and the relative errors of these methods are analysed. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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17 pages, 8717 KiB  
Article
Design and Implementation of a Low-Cost Torque Sensor for Manipulators
by Miroslav Pástor, Martin Hagara, Štefan Gašpár and Milan Sapieta
Appl. Sci. 2023, 13(16), 9406; https://doi.org/10.3390/app13169406 - 18 Aug 2023
Cited by 3 | Viewed by 813
Abstract
Humanoid and collaborative robots find their application in numerous sectors, such as automotive, electrical and mechanical engineering, not excluding the field of bioengineering. They replace repetitive and often monotonous human activity. As the trend nowadays is for continuous optimization of production processes, their [...] Read more.
Humanoid and collaborative robots find their application in numerous sectors, such as automotive, electrical and mechanical engineering, not excluding the field of bioengineering. They replace repetitive and often monotonous human activity. As the trend nowadays is for continuous optimization of production processes, their advantage is easy relocation and operative application to new tasks, which allows the automation of practically all manual work. A common feature of manipulators is the control of the positioning of the actuators, primarily by adjusting the parameters of the drive units. Feedback is often implemented through various sensors that provide real-time information. However, most of the sensors in use do not provide information that would allow obtaining data on the history of the operating load in order to assess the further safe and reliable operation of the mechanical parts. This paper presents a low-cost torque sensor that was proposed by modifying the design of an existing part. The torque sensor was developed on the principle of strain gauge measurement. The results of strain–stress analysis obtained by numerical modelling were experimentally validated under static and dynamic loading. Practical application is mainly the development and long-term testing of prototypes of various types of manipulators and collaborative robots, where high accuracy and repeatability of positioning are essential. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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10 pages, 1254 KiB  
Article
A Similarity Model of Specific Heat Loss Determined by Dimensional Analysis
by Mária Čarnogurská, Miroslav Příhoda, Marián Lázár, Natália Jasminská, Tomáš Brestovič and Michal Puškár
Appl. Sci. 2023, 13(14), 8055; https://doi.org/10.3390/app13148055 - 10 Jul 2023
Viewed by 598
Abstract
This article describes an innovative method for the determination of heat flow (specific heat loss; linear heat flow density) from a one-metre length of a twin pipe directly-buried heat network. Such heat losses are currently described by applying analytical procedures based on the [...] Read more.
This article describes an innovative method for the determination of heat flow (specific heat loss; linear heat flow density) from a one-metre length of a twin pipe directly-buried heat network. Such heat losses are currently described by applying analytical procedures based on the heat transfer theory. It is rather complicated to accurately express the heat loss using such procedures, due to the necessity to determine the individual values of thermal resistance. A simpler method to express heat loss is the balance method, as it requires measuring a temperature gradient Δt between the starting point of the heat network and the end point of the heat collection. A suitable measuring device must provide high-accuracy measurements of the temperature. In the case of very well-insulated distribution pipelines and short pipes, the temperature measurements must be accurate to the hundredths of a degree Celsius. It is impossible to install such devices as fixed equipment on every heat distribution network, due to such networks measuring many kilometres and the cost of the appropriate measuring technology. For the aforesaid reasons, the authors created a mathematical model for specific heat losses based on dimensional analysis. This method facilitates the identification of dimensionless criteria based on the relevant dimensional quantities. Functional correlations between the identified criteria may be identified on the basis of the results of physical or numerical experiments. In this study, a database of the results obtained from physical experiments conducted on two heat networks was used. The output of the similarity model was a function describing the heat flow from a one-meter pipe length that was applicable to various alternatives in relation to the geometrical, physical and boundary conditions. The standard deviation of a difference in the heat losses identified by applying the balance method and using the proposed criterial equation for a twin pipe directly-buried pre-insulated heat network was 0.515 W·m−1. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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14 pages, 1771 KiB  
Article
Numerical Identification of Deep Muscle Residual Tensions (Tones) Based on Multi-Directional Trunk Stiffness Data
by Hichem Smaoui, Sadok Mehrez and Mohamed Omri
Appl. Sci. 2022, 12(22), 11802; https://doi.org/10.3390/app122211802 - 20 Nov 2022
Viewed by 981
Abstract
This work proposes an identification methodology to estimate the residual tension values (tones) for the human trunk muscles, including the deep ones, using multidirectional trunk stiffness data in association with numerical modeling. The role of this residual muscle tension or contraction is to [...] Read more.
This work proposes an identification methodology to estimate the residual tension values (tones) for the human trunk muscles, including the deep ones, using multidirectional trunk stiffness data in association with numerical modeling. The role of this residual muscle tension or contraction is to maintain posture and balance. Knowledge of the tone is useful for the diagnosis and treatment of several spinal diseases and is important for realistic modeling and numerical simulation of trunk behavior. Most of the existing techniques for the measurement and estimation of muscle tones, such as electromyography, are restricted to superficial muscles. Those designed for deep muscles are invasive and present risks of infection and pain. In contrast, the proposed identification approach is painless and safe for the subject. It proceeds by matching the experimental trunk stiffness with numerical upper and lower estimates of the stiffness, to construct an inclusive solution domain of possible tone values of superficial as well as deep trunk muscles. By dividing the trunk muscles into three classes, each assumed to share the same tone ratio, a reasonable solution domain is obtained that exhibits a significant overlap with ranges of muscle tones found in the literature. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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17 pages, 6544 KiB  
Article
Rectification of Gas Pipeline Bridging with the Support of Experimental Stress Analysis and Means of Regression and Correlation Analysis
by Peter Frankovský, Peter Sivák, Ingrid Delyová, Darina Hroncová and Pavol Štuller
Appl. Sci. 2022, 12(20), 10555; https://doi.org/10.3390/app122010555 - 19 Oct 2022
Cited by 1 | Viewed by 1078
Abstract
The paper deals with the connection between the issue of rectification of the structural system and the corresponding experimental and related statistical analysis of stresses. The solution was demonstrated in the example of replacing the aboveground gas pipeline with an underground solution. During [...] Read more.
The paper deals with the connection between the issue of rectification of the structural system and the corresponding experimental and related statistical analysis of stresses. The solution was demonstrated in the example of replacing the aboveground gas pipeline with an underground solution. During the implementation of landscaping for the underground solution, there was a risk of damage to the existing structure. Due to the specific problems in stress analysis based on strain gauge measurements, especially with regard to the narrow range of gas pressure as the primary input quantity, the obtained data had to be subjected to complex statistical procedures. Several linear and non-linear regression models were compiled and subjected to normality, homoscedasticity, and autocorrelation tests. The data obtained in this manner ruled out the possibility of limited state occurrence on the existing structure and, in conjunction with other information, enabled the successful completion of the rectification process to its current form. The scientific added value of the contribution should be the demonstration of procedure methodology and relatively unconventional use of regression and correlation analysis methods and means in the technical field for stress analysis in solving engineering practice problems. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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16 pages, 3484 KiB  
Article
Analysis of a Nature-Inspired Shape for a Vertical Axis Wind Turbine
by Javier Blanco Damota, Juan de Dios Rodríguez García, Antonio Couce Casanova, Javier Telmo Miranda, Claudio Giovanni Caccia and María Isabel Lamas Galdo
Appl. Sci. 2022, 12(14), 7018; https://doi.org/10.3390/app12147018 - 12 Jul 2022
Cited by 6 | Viewed by 3044
Abstract
Wind energy is gaining special interest worldwide due to the necessity of reducing pollutant emissions and employ renewable resources. Traditionally, horizontal axis wind turbines have been employed but certain situations require vertical axis wind turbines. With a view to improve the efficiency of [...] Read more.
Wind energy is gaining special interest worldwide due to the necessity of reducing pollutant emissions and employ renewable resources. Traditionally, horizontal axis wind turbines have been employed but certain situations require vertical axis wind turbines. With a view to improve the efficiency of a vertical axis wind turbine Savonius type, the present work proposes a bioinspired design blade profile relying on the Fibonacci spiral. This shape is repeatedly presented in nature and thus it leads to a bio-inspired blade profile. A numerical model was carried out and it was found that the Fibonacci shape improves the performance of the original Savonius shape, based on semicircular blade profiles. Particularly, the Fibonacci blade profile increases around 14% the power in comparison with the Savonius blade profile. Besides this comparison between Savonius and Fibonacci, a research study was carried out to improve the efficiency of the Fibonacci turbine. To this end, the effect of several parameters was analyzed: number of blades, aspect ratio, overlap, separation gap, and twist angle. Improvements on the average power greater than 30% were obtained. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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12 pages, 3952 KiB  
Article
Development and Testing of Copper Filters for Efficient Application in Half-Face Masks
by Beáta Ballóková, Marián Lázár, Natália Jasminská, Zuzana Molčanová, Štefan Michalik, Tomáš Brestovič, Jozef Živčák and Karol Saksl
Appl. Sci. 2022, 12(13), 6824; https://doi.org/10.3390/app12136824 - 05 Jul 2022
Viewed by 1489
Abstract
SARS-CoV-2 is the causative agent of severe acute respiratory diseases. Its main transmission pathway is through large and small respiratory droplets, as well as a direct and indirect contact. In this paper, we present the results of the development and research of copper [...] Read more.
SARS-CoV-2 is the causative agent of severe acute respiratory diseases. Its main transmission pathway is through large and small respiratory droplets, as well as a direct and indirect contact. In this paper, we present the results of the development and research of copper filters produced by powder technology. Four types of copper powders were tested. Technological parameters, a microstructure, an energy dispersive X-ray (EDX) analysis, and fractography of copper (Cu) filters are reported. The pressure losses in the P-Cu-AW315 filter showed a very favorable value for using the filter in half-face masks that meet the requirements of European norms (EN). An X-ray tomography measurement was carried out at the I12-JEEP beamline. A relative volume of grains and pores was estimated (on the basis of the segmentation results) to be approximately 50% to 50% of the investigated filter volume. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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19 pages, 2432 KiB  
Article
The Relationship between Process Capability and Quality of Measurement System
by Štefan Markulik, Jozef Petrík, Marek Šolc, Peter Blaško, Pavol Palfy and Lenka Girmanová
Appl. Sci. 2022, 12(12), 5825; https://doi.org/10.3390/app12125825 - 08 Jun 2022
Cited by 2 | Viewed by 1448
Abstract
This article deals with the design of appropriate measures that had to be taken for the implemented measurement system. The measurement result was significantly negatively affected by several factors. Forty-five samples of shafts used in the production of surgical drills were measured. Measurements [...] Read more.
This article deals with the design of appropriate measures that had to be taken for the implemented measurement system. The measurement result was significantly negatively affected by several factors. Forty-five samples of shafts used in the production of surgical drills were measured. Measurements were performed by metrological appraisers with a calibrated digital micrometer. Measurement and subsequent data processing revealed low process capability (CP and PP indices). A large portion of the shafts had an observed size below the lower specific limit (LSL). Therefore, it was necessary to take corrective action. This paper focuses on the corrective measures implemented in the measurement system. The micrometer met the requirements of the standard and was metrologically capable. The shafts were measured by eight metrological appraisers, so attention was focused on the potential impact of the metrological appraiser. The measured data were evaluated by uncertainty analysis, paired t-tests, measurement systems analysis (MSA) and Cohen’s kappa. The number of non-compliant shafts was shown to increase with decreasing measurement capability. The measurement system was evaluated as conditionally capable, even incapable. One possibility was to identify the optimal pair of metrological appraisers. The pair of metrological appraisers E and F appeared to be the most suitable combination for most methods. Due to the relatively high %EV index, the second option was to improve the work with the measuring instrument, that is, improve the training and supervision of metrological appraisers in the measurement process. Repeated measurements by the pair with the highest capability (metrological appraisers E and F) resulted in an increase in the value of the capability indices and a decrease in the number of shafts out of tolerance for the same shafts. As the value of these indices was lower than 1.33 during repeated measurements, corrective measures had to be taken, not only in the measurement system, but also in the production system. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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33 pages, 3943 KiB  
Article
A Non-Anthropomorphic Bipedal Walking Robot with a Vertically Stabilized Base
by Ivan Virgala, Ľubica Miková, Tatiana Kelemenová, Martin Varga, Róbert Rákay, Marek Vagaš, Ján Semjon, Rudolf Jánoš, Marek Sukop, Peter Marcinko and Peter Tuleja
Appl. Sci. 2022, 12(9), 4108; https://doi.org/10.3390/app12094108 - 19 Apr 2022
Cited by 10 | Viewed by 2223
Abstract
The paper deals with the proposed concept of a biped robot with vertical stabilization of the robot’s base and minimization of its sideways oscillations. This robot uses 6 actuators, which gives good preconditions for energy balance compared to purely articulated bipedal robots. In [...] Read more.
The paper deals with the proposed concept of a biped robot with vertical stabilization of the robot’s base and minimization of its sideways oscillations. This robot uses 6 actuators, which gives good preconditions for energy balance compared to purely articulated bipedal robots. In addition, the used linear actuator is self-locking, so no additional energy is required for braking or to keep it in a stable position. The direct and inverse kinematics problems are solved by means of a kinematic model of the robot. Furthermore, the task is aided by a solution for locomotion on an inclined plane. Special attention is focused on the position of the robot’s center of gravity and its stability in motion. The results of the simulation confirm that the proposed concept meets all expectations. This robot can be used as a mechatronic assistant or as a carrier for handling extensions. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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18 pages, 13346 KiB  
Article
Measurements of Operating Parameters of a Metal Hydride Compressor with a Heat Pump
by Tomáš Brestovič, Natália Jasminská and Marián Lázár
Appl. Sci. 2022, 12(7), 3302; https://doi.org/10.3390/app12073302 - 24 Mar 2022
Cited by 5 | Viewed by 1584
Abstract
The hydrogen compression that occurs in a metal hydride compressor is based on the chemical and thermal processes of hydrogen absorption and desorption into an intermetallic structure of metals. The concept presented in this article is centred on the use of an optimal [...] Read more.
The hydrogen compression that occurs in a metal hydride compressor is based on the chemical and thermal processes of hydrogen absorption and desorption into an intermetallic structure of metals. The concept presented in this article is centred on the use of an optimal metal alloy that is capable of absorbing hydrogen into its structure at a low temperature and pressure. After such an alloy is heated up, its pressure will significantly increase, and this facilitates the compression of hydrogen without it being in direct contact with the movable parts of the compressor. As a result, the safety of the compression process is increased. The hydrogen compressor contains a pair of tandem metal hydride (MH) tanks with an integrated heat exchanger. The tanks are alternately heated and cooled, so that while hydrogen is absorbed in one of the tanks it is concurrently desorbed in the other tank. The unique nature of the prototype single-stage metal hydride compressor consists in using a heat pump that facilitated a significant reduction of the consumed electric energy in the heat transport between the tandem-arranged tanks. The purpose of this investigation was to examine the possibility of integrating a heat pump as a source of heat and cold for the process of absorption- and desorption-based hydrogen compression. With the prototype MH compressor presented in this article, a compression ratio of ε = 2.0 was achieved while the tanks were operated at temperatures ranging from 12 to 55 °C. In a single cycle, the compressor worked with 166 litres of hydrogen, which was absorbed into 3.125 kg of the La0.85Ce0.15Ni5 alloy. The average heating power that was achieved on the side of the condenser that heated the MH1 tank was 362 W, and the cooling power that was achieved on the evaporator side was 300 W. The achieved value of the heat pump COP was 2.92. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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15 pages, 2664 KiB  
Article
Fire Models as a Tool for Evaluation of Energy Balance in Burning Space Relating to Building Structures
by Marianna Tomaskova, Jiri Pokorny, Petr Kucera, Michaela Balazikova and Daniela Marasova, Jr.
Appl. Sci. 2022, 12(5), 2505; https://doi.org/10.3390/app12052505 - 28 Feb 2022
Cited by 2 | Viewed by 2283
Abstract
Fire is defined as an extremely hazardous event, causing a threat to life and health of persons, but also damage to the economic sphere. It has been shown many times that fire can occur anywhere and at any time. In order to minimize [...] Read more.
Fire is defined as an extremely hazardous event, causing a threat to life and health of persons, but also damage to the economic sphere. It has been shown many times that fire can occur anywhere and at any time. In order to minimize the risk of fire manifestations, it is necessary to understand its course. In technical practice, computational models are used to determine the partial manifestations of fire, such as fire spread rate, smoke generation rate in the burning area, formation of toxic burning products, flame height, and others. One of the important characteristics is also the energy balance in the burning area relating to the character of burning material, access of oxygen necessary for exothermic reaction of burning, and reaction of the installed safety devices. In this paper we will point out the fire safety of the building. The FDS (Fire Dynamics Simulator) model is recently used in practice, and its advantage is the possibility to model fire even in large and atypical spaces. The contribution of this paper is the practical application of fire safety of construction using the FDS Model, to reduce the cost of fire safety for the structure being constructed. Attention was paid to evaluating how the heat energy that is released during a fire can be influenced by the installed stable fire-extinguishing equipment, taking into consideration the fire resistance of the building structures. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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12 pages, 3878 KiB  
Article
Analysis of Fault Conditions in the Production of Prestressed Concrete Sleepers
by Štefan Markulik, Jozef Petrík, Marek Šolc, Peter Blaško, Pavol Palfy, Andrea Sütőová and Lenka Girmanová
Appl. Sci. 2022, 12(2), 928; https://doi.org/10.3390/app12020928 - 17 Jan 2022
Cited by 5 | Viewed by 1737
Abstract
Industries demand that their products are high quality with the least number of defects due to the rapid improvement in manufacturing technology. Quality is a critical criterion for evaluation in manufacturing firms. The production of a final product that can meet customer requirements [...] Read more.
Industries demand that their products are high quality with the least number of defects due to the rapid improvement in manufacturing technology. Quality is a critical criterion for evaluation in manufacturing firms. The production of a final product that can meet customer requirements is essential in a sustainable supply chain system to reduce costs, increase productivity and provide high-quality products. The aim of the study is to identify the root cause of defects emerging in the production process of prestressed railway concrete sleepers. Ishikawa diagram and Pareto analysis were used to identify the root cause. The results showed that the cause of the faulty concrete sleeper is the breaking of the bolts, which are supplied by the external provider. Since the supplier refused to accept the complaint, chemical analysis and measuring of hardness and microhardness of bolts were realized. It showed that the hardness of the bolts does not achieve the values, which should be achieved after the declared heat-treatment. As a corrective action, the input control of bolts hardness was proposed as well as establishing the team cooperating with the supplier to improve the heat treatment process, which will be the objective of further study. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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13 pages, 2577 KiB  
Article
Method of Medical Equipment Evaluation and Preparation for On-Demand Additive Manufacturing with the Conventional Supply Chain Being Broken: A Case Study of Mask Filter Adapter Production during COVID-19
by Michał Karoluk, Gustaw Koenig and Tomasz Kurzynowski
Appl. Sci. 2021, 11(24), 12016; https://doi.org/10.3390/app112412016 - 17 Dec 2021
Cited by 3 | Viewed by 2028
Abstract
A year after the first cases, the COVID-19 pandemic continued to put immense pressure on healthcare systems worldwide. With supply chains broken, the only opportunity for hospitals was to turn to unconventional solutions to overcome medical equipment shortages in the shortest possible time. [...] Read more.
A year after the first cases, the COVID-19 pandemic continued to put immense pressure on healthcare systems worldwide. With supply chains broken, the only opportunity for hospitals was to turn to unconventional solutions to overcome medical equipment shortages in the shortest possible time. This paper describes the methodology that allows the preparation of medical equipment to be additionally manufactured in keeping with medical requirements. The proposed method focuses on cytotoxicity tests against HaCaT, L929, A549 cell lines, and the assessment of potential antimicrobial properties of materials. The application of the proposed method is shown by the example of an adapter that connects a full mask with widely available DAR filters. The prototyping and fabrication of adapters were conducted with the fused deposition modelling (FDM) and selective laser sintering (SLS) technologies. The adapters increased the number of masks available to medical personnel, and by the same token, ensured the continuity of their work. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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12 pages, 1154 KiB  
Article
The Influence of Nutrient Medium Composition on Escherichia coli Biofilm Development and Heterologous Protein Expression
by Alexandra Soares, Luciana C. Gomes, Gabriel A. Monteiro and Filipe J. Mergulhão
Appl. Sci. 2021, 11(18), 8667; https://doi.org/10.3390/app11188667 - 17 Sep 2021
Cited by 7 | Viewed by 3204
Abstract
In the present study, the effects of different nutrient media on the development of Escherichia coli biofilms and the production of a heterologous protein were examined. E. coli JM109(DE3) cells transformed with pFM23 plasmid carrying the gene for enhanced green fluorescent protein (eGFP) [...] Read more.
In the present study, the effects of different nutrient media on the development of Escherichia coli biofilms and the production of a heterologous protein were examined. E. coli JM109(DE3) cells transformed with pFM23 plasmid carrying the gene for enhanced green fluorescent protein (eGFP) expression were used. Cells were grown in two different culture media, Lysogenic Broth (LB) and M9ZB, in a flow cell system for 10 days. Epifluorescence microscopy, fluorimetry, and a high-performance liquid chromatography (HPLC) method based on hydrophobic interaction chromatography (HIC) were used to assess bacterial growth, plasmid copy number (PCN), and eGFP production in both planktonic and biofilm cells. The results showed that biofilm development was favored in M9ZB medium when compared with LB. However, the number of eGFP-expressing cells was higher in LB for both planktonic and sessile states (two-fold and seven-fold, respectively). In addition, the PCN in biofilm cells was slightly higher when using LB medium (on average, 29 plasmids per cell versus 20 plasmids per cell in M9ZB), and higher plasmid stability was observed in biofilms formed in LB compared to their planktonic counterparts. Hence, E. coli biofilms grown in LB enhanced both plasmid stability and capacity to produce the model heterologous protein when compared to M9ZB. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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12 pages, 4263 KiB  
Article
The Determination of the Inward Leakage through the Skin–Facepiece Interface of the Protective Half-Mask
by Tomáš Brestovič, Marián Lázár, Natália Jasminská, Jozef Živčák, Radovan Hudák, Lukáš Tóth and Romana Dobáková
Appl. Sci. 2021, 11(17), 8042; https://doi.org/10.3390/app11178042 - 30 Aug 2021
Cited by 2 | Viewed by 1518
Abstract
The present article describes the measurements of flow rates of the inward air leakage through the skin–facepiece interface of a protective half-mask with replaceable filters. The measurements were carried out while applying an indirect method in which the pressure drops in a compressed [...] Read more.
The present article describes the measurements of flow rates of the inward air leakage through the skin–facepiece interface of a protective half-mask with replaceable filters. The measurements were carried out while applying an indirect method in which the pressure drops in a compressed air container were measured, and subsequently, the total flow rate of the leak was calculated. This methodology facilitated measuring extremely low air flow rates at the atmospheric pressure of 3.2 × 10−6 m3·s−1. A numerical analysis of the inward air leakage through the gaps between the face and the facepiece of the mask was carried out with the aim of identifying the cross-sectional area of the leak. With the tested mask, which was made of Santoprene 8281-45MED, the leakage measured during inhalation was 0.21%, which corresponded to the cross-sectional area of only 0.14 mm2. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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11 pages, 958 KiB  
Article
Application of FTA Analysis for Calculation of the Probability of the Failure of the Pressure Leaching Process
by Stefan Markulik, Marek Šolc, Jozef Petrík, Michaela Balážiková, Peter Blaško, Juraj Kliment and Martin Bezák
Appl. Sci. 2021, 11(15), 6731; https://doi.org/10.3390/app11156731 - 22 Jul 2021
Cited by 16 | Viewed by 2209
Abstract
European Union legislation requires organizations to assess their processes in the context of risk management. The main task of risk management is to manage all risks that can significantly affect the outcome of processes. The article is focused on risk evaluation in pressure [...] Read more.
European Union legislation requires organizations to assess their processes in the context of risk management. The main task of risk management is to manage all risks that can significantly affect the outcome of processes. The article is focused on risk evaluation in pressure leaching at elevated temperature using the method Fault Tree Analysis (FTA). The effectivity of pyrite and arsenic pyrite decomposition by oxidative pressure leaching is influenced by the duration of the process, by the temperature, concentration of the leaching solution and by a density of the slurry. It was found that, under equitable conditions, the arsenic pyrite decomposes more intensely than pyrite. Under laboratory conditions, leaching is performed in an autoclave. Due to the aggressive environment, increased pressure and temperature, process failure is possible. Its probability was calculated by FTA. It has been found that the probability of the top event in the examined process was disproportionately high (0.057) and represents an invitation to take corrective actions. The Monte Carlo method was used for the simulation of the effect the probability of basic events on the probability of the top event—the failure of the leaching process. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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11 pages, 934 KiB  
Article
Protoporphyrin IX Based All-Solid-State Ion-Selective Electrodes for Choline Determination In Vitro
by You Wang, Siyuan Ma, Hongqun Zou, Zhenyu Wu, Zhiyuan Luo and Guang Li
Appl. Sci. 2021, 11(12), 5549; https://doi.org/10.3390/app11125549 - 15 Jun 2021
Cited by 1 | Viewed by 1701
Abstract
Protoporphyrin IX-based all-solid-state choline (Ch) ion-selective electrodes (ISEs) were fabricated and characterized. Poly (3,4-ethylene dioxythiophene) doped with poly (styrene sulfonate) (PEDOT/PSS) functioning as an ion-to-electron transducer was electropolymerized on the gold wire (0.5 mm diameter). The conductive polymer was covered with a Ch [...] Read more.
Protoporphyrin IX-based all-solid-state choline (Ch) ion-selective electrodes (ISEs) were fabricated and characterized. Poly (3,4-ethylene dioxythiophene) doped with poly (styrene sulfonate) (PEDOT/PSS) functioning as an ion-to-electron transducer was electropolymerized on the gold wire (0.5 mm diameter). The conductive polymer was covered with a Ch selective membrane containing protoporphyrin IX as an ionophore, which exhibited a lower detection limit of 0.49 μM with the potentiometric method. The Ch sensor performed a wide linear range from 1 μM to 1 mM, a fast response time of less than 5 s, and a decent selectivity of common inorganic and organic ions in the human body. Characteristics such as pH and temperature stability, life span, reproducibility and repeatability were also investigated to be satisfied. With the background of artificial cerebrospinal fluid, the recovery rate in 10−5 M of Ch solution was measured by the standard addition method, revealing the potential for biological application. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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12 pages, 4233 KiB  
Article
Improving Quality in the Process of Hot Rolling of Steel Sheets
by Stefan Markulik, Anna Nagyova, Renata Turisova and Tomas Villinsky
Appl. Sci. 2021, 11(12), 5451; https://doi.org/10.3390/app11125451 - 11 Jun 2021
Cited by 13 | Viewed by 3186
Abstract
The hot rolling of steel sheets is a highly energy-intensive process. There are technical and operational issues associated with this process, and the causes of these issues can be various. This study involved analysis of one issue that has a great influence on [...] Read more.
The hot rolling of steel sheets is a highly energy-intensive process. There are technical and operational issues associated with this process, and the causes of these issues can be various. This study involved analysis of one issue that has a great influence on the resulting surface quality of rolled sheet metal: rolled foreign material. After the sheet cools, rolled foreign material tends to fall off and a hole then remain on the surface of the sheet. This paper focuses on the search for the root causes of the occurrence of foreign material rolling. The basic categorization of the causes of this issue was performed by experienced long-term operators. The 4M method (man, machine, method, and material) was used to categorize the causes. Pairwise comparison was used to verify the result. Using energy dispersive spectroscopy analysis, the origin of the foreign material was identified. The analysis confirmed that the foreign material was not derived from the primary material. Further research showed that the cause of the issue was the guide rulers, which are a structural part of the rolling mill. Measures were taken to significantly reduce the incidence of the problem, which also had the effect of reducing financial losses, which fell by a third in 18 weeks. In the future, it will be necessary to make design changes (modernization of the rolling mill), which will, however, require more financial investment. Full article
(This article belongs to the Special Issue Mechanical and Biomedical Engineering in Paradigm)
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