Applied Sciences

2 pages, 163 KiB

Open AccessEditorial

Special Issue on Green Construction, Maintenance, Structural Health Monitoring and Non-Destructive Testing in Complex Structures and Infrastructures

by Wensheng Wang, Guojin Tan, Tao Yang, Chunli Wu and Xin He

Appl. Sci. 2022, 12(19), 10189; https://doi.org/10.3390/app121910189 - 10 Oct 2022

Viewed by 1261

Abstract

It is widely acknowledged that structural design, new construction technology, maintenance, monitoring and testing remain core aspects of civil engineering [...] Full article

(This article belongs to the Special Issue Green Construction, Maintenance, Structural Health Monitoring and Non-destructive Testing in Complex Structures and Infrastructures)

17 pages, 1844 KiB

Open AccessArticle

Thermodynamic Modeling and Exergoenvironmental Analysis of a Methane Gas-Powered Combined Heat and Power System

by Michael Adedeji, Muhammad Abid, Humphrey Adun, Ayomide Titus Ogungbemi, David Alao and Juliana Hj Zaini

Appl. Sci. 2022, 12(19), 10188; https://doi.org/10.3390/app121910188 - 10 Oct 2022

Cited by 1 | Viewed by 1817

Abstract

A combined heat and power (CHP) system powered by methane gas is modelled and analyzed in this study. The Thermolib MATLAB extension is used to model the system by graphically connecting the Thermolib standard components through fluid flows. An exergoenvironmental analysis is also [...] Read more.

A combined heat and power (CHP) system powered by methane gas is modelled and analyzed in this study. The Thermolib MATLAB extension is used to model the system by graphically connecting the Thermolib standard components through fluid flows. An exergoenvironmental analysis is also performed using EES. The results show that, for an input thermal energy rate of 29.9 MW, the Brayton and Rankine cycles generated 9.8 MW and 7.5 MW of net power, respectively. The heat pump was also able to supply 1.4 MW as its output. The total energy efficiency of the cogeneration system was 62% with the Brayton cycle working at 33%, the Rankine cycle at 36%, and the ammonia heat pump at a coefficient of performance (COP) of 9.1. The system also achieved an overall exergy efficiency of 78%. Furthermore, the system was examined at different levels by varying input parameters such as the pressure ratio of both the Brayton cycle and the heat pump, the pressure of the steam in the Rankine cycle, and the inlet energy from the combustion chamber of the system. The exergoenvironmental modeling of the system showed that the exergy stability factor and exergetic sustainability index increased from 0.41 to 0.47 and from 0.6 to 0.64 with increasing inlet combustion energy; this can be seen as a good indicator of its stability and sustainability. Full article

(This article belongs to the Special Issue Combustion and Emissions of Hydrocarbon-Fueled Engines)

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15 pages, 3851 KiB

Open AccessArticle

Experimental Investigation of Interface Characteristics between Geogrid and Coarse-Grained Soil in a Seasonally Frozen Area

by Qiyu Bai, Jie Liu, Yong Wang, Haoyuan Du and Bin Wang

Appl. Sci. 2022, 12(19), 10187; https://doi.org/10.3390/app121910187 - 10 Oct 2022

Cited by 1 | Viewed by 1531

Abstract

In seasonally frozen soil regions, the influence of temperature change on reinforced-soil engineering cannot be ignored. In particular, the mechanical properties of the reinforced-soil interface have an important impact on the overall stability and long-term service performance of reinforced soil engineering. To explore [...] Read more.

In seasonally frozen soil regions, the influence of temperature change on reinforced-soil engineering cannot be ignored. In particular, the mechanical properties of the reinforced-soil interface have an important impact on the overall stability and long-term service performance of reinforced soil engineering. To explore the interface characteristics and reinforcement mechanism between geogrids and coarse-grained soil under negative temperatures, this paper takes the typical coarse-grained soil in Xinjiang as the material and carries out a direct shear test of the reinforcement–soil interface under different normal stresses, water contents and temperatures. The curve characteristics of the shear displacement-shear stress, the change trend of the peak shear stress and the formation mechanism between the geogrid and coarse-grained soil interface under freezing and nonfreezing conditions are thoroughly analyzed. The formation mechanism of the dilatancy characteristics of the reinforced-soil interface is explained by combining the Mohr-Coulomb strength criterion and apparent friction coefficient. It is concluded that the trend of the shear displacement-shear stress curve between the geogrid and coarse-grained soil interface under the nonfreezing state and freezing state is basically the same. In a state of low normal stress, the curve has no obvious peak, which is closer to the ideal elastic-plastic double linear model. In a state of high normal stress, the curves have more obvious peaks, and the curve type is closer to the elastic-strain softening type. In the nonfreezing state, the shear strength of the reinforcement–soil interface has a great correlation with the water content, which is different in the freezing state. The main sources of the difference are the cementation of pore ice in the soil skeleton in the frozen state, the improvement of the strength of the soil particles themselves, and the further interlocking effect of the geogrid on the soil. In comparison with the reinforced coarse-grained soil under the nonfrozen state, the shear strength under the frozen state is significantly improved. In comparison with coarse-grained soil reinforced by geogrids in the nonfreezing state (0 °C), the shear strength of the frozen state (−5 °C) is significantly improved. Under normal stresses of 40 kPa, 60 kPa, and 80 kPa, when the water content is 2%, the corresponding peak shear stress increases by 19.39%, 21.71% and 11.34%, respectively. When the water content is 4.5%, the corresponding peak shear stress decreases by 29.98%, 16.17%, and 13.83%. When the water content is 7%, the corresponding peak shear stress decreases by 50.85%, 18.64%, and 21.96%. The apparent friction coefficient between the geogrid coarse-grained soil interface in the nonfrozen state and frozen state decreases with increasing normal stress. With the decrease in temperature, the dilatancy phenomenon of the reinforced soil composite is more obvious. The research results can provide a reference for the construction of reinforced engineering in seasonal frozen soil areas. Full article

(This article belongs to the Section Civil Engineering)

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17 pages, 626 KiB

Open AccessArticle

On Noise Modeling of Capacitive Feedback Transimpedance Amplifiers in CMOS

by Agata Romanova and Vaidotas Barzdenas

Appl. Sci. 2022, 12(19), 10186; https://doi.org/10.3390/app121910186 - 10 Oct 2022

Cited by 1 | Viewed by 1925

Abstract

The work reports on the development of a detailed noise current model for a low-noise capacitive feedback transimpedance amplifier (TIA) in CMOS. The proposed TIA circuit implements the programmable-gain using an array of discretely controlled feedback capacitors and resistances in the biasing circuit [...] Read more.

The work reports on the development of a detailed noise current model for a low-noise capacitive feedback transimpedance amplifier (TIA) in CMOS. The proposed TIA circuit implements the programmable-gain using an array of discretely controlled feedback capacitors and resistances in the biasing circuit and is originally designed bearing in mind low-noise requirements for optical time-domain reflectometer (OTDR) applications with the base gain of 10 kΩ at 1 GHz bandwidth and noise levels below 5.0 pA/

\sqrt{Hz}

. The newly developed model for input-referred noise current spectral density complements the previously suggested transimpedance gain model and takes into account both the primary and secondary noise sources so far ignored in the models known in the literature. The proposed noise model consists of five terms and includes the effects caused by biasing components of the input stage and the noise shaping from the source follower. The performance of the developed noise model is evaluated using the post-layout simulation in 0.18

μ

m CMOS and 0.25

μ

m BiCMOS technologies, and a close match of the proposed model is demonstrated in the results of the post-layout simulation with the noise level below 1.8 pA/

\sqrt{Hz}

for the base gain configuration in CMOS. A comparison to available noise models from the literature confirms that previously known noise models for this promising TIA architecture omitted important noise components present in practical and physically realizable circuits and, therefore, resulted in underestimating the base noise level by a factor of two to three, while completely ignoring the flicker noise mapping in the low-frequency range. Full article

(This article belongs to the Special Issue Advanced Integrated Circuit Technology and Application)

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21 pages, 3994 KiB

Open AccessArticle

Pore Space Connectivity in Different Rock-Physics Methods—Similarity and Differences

by Irina Berezina and Irina Bayuk

Appl. Sci. 2022, 12(19), 10185; https://doi.org/10.3390/app121910185 - 10 Oct 2022

Viewed by 1692

Abstract

This study is focused on the analysis of pore space connectivity in reservoir rocks. This parameter is of vital importance for the oil and gas industry since it controls hydraulic permeability. Five methods of rock physics are used for this goal. Three of [...] Read more.

This study is focused on the analysis of pore space connectivity in reservoir rocks. This parameter is of vital importance for the oil and gas industry since it controls hydraulic permeability. Five methods of rock physics are used for this goal. Three of these methods (self-consistent version of generalized singular approximation, Berryman self-consistent method, and differential scheme) take into account the pore space connectivity implicitly. The other two methods, the f-model of the generalized singular approximation and a similar modification of the Berryman method suggested in this work, allow for quantifying the connectivity via a special parameter (f-parameter). In order to reveal a physical meaning of this parameter, two simple models of carbonate rock (porous-cracked limestone) are considered. The first model is a double porosity model containing spherical pores and cracks. The second model contains only spherical pores, and their connectivity is expressed via the f-parameter. The pores and cracks are filled with brine and gas. Application of the two groups of methods for modeling the effective elastic properties of the carbonate rock gives a possibility of relating the f-parameter to the characteristics of the cracks and pores. The f-parameter is shown to be controlled by the relative crack volume in the total pore space. An increase in crack porosity and crack density leads to an increase in the f-parameter. A good correlation of the f-parameter with crack density is demonstrated. It is shown that for the porosity range 2–20%, a relationship between the f-parameter and crack density

ε

, in general, has the form

f = a \log_{10} {(ε)}^{2} + b \log_{10} (ε) + c

for

ε \leq ε_{m i n}

. For the crack density less than

ε_{m i n}

the f-parameter can be approximated by a constant value f_min. The values of

ε_{m i n}

and f_min and coefficients a, b, and c depend on the porosity of spherical pores, saturation type, and pair of methods used for finding the link. These results give f-models an advantage in searching zones of the enhanced permeability and quantifying the ability of these zones to filtrate fluids. Full article

(This article belongs to the Special Issue Multiscale Rock-Physics Modeling)

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15 pages, 5119 KiB

Open AccessArticle

Study on Sand-Accumulation Changes of Highway and Formation Mechanism of Sand Damage in Drifting Dunes Areas

by Feng Han, Chengxiang Wang, Zhibo Liu, Liangying Li and Wenhua Yin

Appl. Sci. 2022, 12(19), 10184; https://doi.org/10.3390/app121910184 - 10 Oct 2022

Cited by 2 | Viewed by 2168

Abstract

After the construction of desert highway, the physiognomy changes caused by surface wind erosion and accumulation not only seriously threaten the stability of road structure, but also have a tremendous impact on the safety of the highway operation and the maintenance work on [...] Read more.

After the construction of desert highway, the physiognomy changes caused by surface wind erosion and accumulation not only seriously threaten the stability of road structure, but also have a tremendous impact on the safety of the highway operation and the maintenance work on the highway. The purpose of this paper is to explore the change of sand sedimentation and the law of sand transport along the highway in the moving dune areas, and to clarify the change of sand flow and the formation mechanism of sand damage in the moving dune areas. Taking the test section of Wuhai-Maqin Expressway in the hinterland of Tengger Desert as the research object, the on-site observation of sand accumulation and the recording of wind information by small weather stations were adopted, supplemented by CFD numerical simulation method, in order to provide reference for the construction of sand control system in moving dune areas. The study results show that: (1) Dunes not only obstruct wind-drift sand but are also the sediment source condition for forming road sand. The windward dunes near the road are affected by wind and the deposition of sand will quickly bury the road in the strong wind season. (2) Compared with highways with flat terrain, the existence of dunes affects the flow field structure and the distribution of sand sedimentation on the highway, in which, under the influence of the gathering effect, the flow velocity reaches the maximum at the top of the dune and a large low-speed recirculation zone is formed on the lee side of the dune, easily causing sand accumulation. (3) Sediment accumulates at the windward side of the embankment or dune where sandy air current is easy to saturate. However, with the increase of wind speed, in addition to the grit carried by the sandy air current itself, new sand rolled up on the windward side of the dunes also form deposits on the road surface and the amount of sand-accumulation on highway surface and leeward side tends to increase. As a result, for the highway in drifting sand dunes areas, sediment prevention and control measures should be taken actively. It is necessary to remove sediment from the road in time and reduce the moving speed of sand dunes and the deposition range of wind-sand flow, ultimately for the purpose of reducing the damage wind-sand activity causes to the highway in desert. Full article

(This article belongs to the Special Issue Prevention and Control of Wind-Blown Sand/Snow Disasters on Railway and Highway)

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15 pages, 4265 KiB

Open AccessArticle

Comparison of Phase-Screen and Geometry-Based Phase Aberration Correction Techniques for Real-Time Transcranial Ultrasound Imaging

by Moein Mozaffarzadeh, Martin D. Verweij, Nico de Jong and Guillaume Renaud

Appl. Sci. 2022, 12(19), 10183; https://doi.org/10.3390/app121910183 - 10 Oct 2022

Cited by 3 | Viewed by 1708

Abstract

While transcranial ultrasound imaging is a promising diagnostic modality, it is still hindered due to phase aberration and multiple scattering caused by the skull. In this paper, we compare near-field phase-screen modeling (PS) to a geometry-based phase aberration correction technique (GB) when an [...] Read more.

While transcranial ultrasound imaging is a promising diagnostic modality, it is still hindered due to phase aberration and multiple scattering caused by the skull. In this paper, we compare near-field phase-screen modeling (PS) to a geometry-based phase aberration correction technique (GB) when an ultrafast imaging sequence (five plane waves tilted from −15 to +15 degrees in the cutaneous tissue layer) is used for data acquisition. With simulation data, the aberration profile (AP) of two aberrator models (flat and realistic temporal bone) was estimated in five isoplanatic patches, while the wave-speed of the brain tissue surrounding the point targets was either modeled homogeneously (ideal) or slightly heterogeneously to generate speckle (for mimicking a more realistic brain tissue). For the experiment, a phased array P4-1 transducer was used to image a wire phantom; a 4.2-mm-thick bone-mimicking plate was placed in front of the probe. The AP of the plate was estimated in three isoplanatic patches. The numerical results indicate that, while all the scatterers are detectable in the image reconstructed by the GB method, many scatterers are not detected with the PS method when the dataset used for AP estimation is generated with a realistic bone model and heterogeneous brain tissue. The experimental results show that the GB method increases the signal-to-clutter ratio (SCR) by 7.5 dB and 6.5 dB compared to the PS and conventional reconstruction methods, respectively. The GB method reduces the axial/lateral localization error by 1.97/0.66 mm and 2.08/0.7 mm compared to the PS method and conventional reconstruction, respectively. The lateral spatial resolution (full-width-half-maximum) is also improved by 0.1 mm and 1.06 mm compared to the PS method and conventional reconstruction, respectively. Our comparison study suggests that GB aberration correction outperforms the PS method when an ultrafast multi-angle plane wave sequence is used for transcranial imaging with a single transducer. Full article

(This article belongs to the Special Issue Computational Ultrasound Imaging and Applications)

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19 pages, 844 KiB

Open AccessArticle

EtWExplorer: Multi-Priority Scheduling Path Exploration Technology Based on Abstract Syntax Tree Analysis

by Xinglu He, Pengfei Wang, Kai Lu and Xu Zhou

Appl. Sci. 2022, 12(19), 10182; https://doi.org/10.3390/app121910182 - 10 Oct 2022

Viewed by 1196

Abstract

Symbolic execution is well known as a dynamic vulnerability discovery technique. Its greatest advantage is the capability to analyze the execution information of the program and to explore the path in the program deterministically. This is a more accurate way to determine if [...] Read more.

Symbolic execution is well known as a dynamic vulnerability discovery technique. Its greatest advantage is the capability to analyze the execution information of the program and to explore the path in the program deterministically. This is a more accurate way to determine if there are vulnerabilities in a program than randomized testing by fuzzing. In addition, symbolic execution does not suffer from the problem of decreasing the capability to discover new paths as more paths are discovered, similar to that caused by random-based fuzzing. However, the reason why symbolic execution is not widely used in vulnerability discovery is mainly due to the state space explosion in the program. The state space explosion severely affects the applicability of symbolic execution. To further improve the applicability of symbolic execution, this paper proposes a path exploration technology based on abstract syntax tree analysis. With the distance between the expression generated by the symbolic execution of the repeat location and the “unsatisfiable” condition of the “unsat” state, we can perform multi-priority scheduling for the repeat location state, thus mitigating the impact of the state space explosion on path exploration. We proposed and implemented EtWExplorer, a multi-priority scheduling technique based on abstract syntax tree analysis. With this technique, we can significantly improve the capability of symbolic execution to discover unknown paths even in state space exploration. Experiments show that EtWExplorer introduces a performance overhead of 72% in the worst case and can improve performance by 294% in the best case. EtWExplorer has a 95% improvement in state space explosion mitigation capability and a 199% to 983% improvement in the path exploration capability of block coverage and a 181% to 1047% improvement in the path exploration capability of edge coverage when facing programs that cause a state space explosion. Full article

(This article belongs to the Section Computing and Artificial Intelligence)

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26 pages, 10926 KiB

Open AccessArticle

Study on Preparation and Properties of Sintered Brick from Multi-Source Solid Waste

by Chen Guo, Jiafeng Kong, Zhenghua Wang, Xiangbin Meng, Yuchao Zhao, Wenhao Wu and Hongzhu Quan

Appl. Sci. 2022, 12(19), 10181; https://doi.org/10.3390/app121910181 - 10 Oct 2022

Cited by 5 | Viewed by 1536

Abstract

The recycling of construction waste and the use of a new sintering process in the field of sintered bricks can greatly solve the problems of clay resource depletion, soil structure destruction, and high CO₂ emissions that always limit the development of the [...] Read more.

The recycling of construction waste and the use of a new sintering process in the field of sintered bricks can greatly solve the problems of clay resource depletion, soil structure destruction, and high CO₂ emissions that always limit the development of the sintered brick field. The study was carried out using an orthogonal experiment to derive the optimal mix ratio for the preparation of sintered bricks, and subsequently, the sintered bricks were prepared using the optimal mix ratio. The experimental results show that the maximum compressive strength of construction waste sintered brick (MRB sintered brick) prepared using high-temperature sintering is 8.1 MPa, and the water absorption is 11. When the waste glass slag is mixed with 10%, it can show a better fluxing effect in the preparation of sintered bricks by mixing construction waste with waste glass slag (MGB sintered bricks), so that the MGB sintered bricks have a higher densification. The compressive strength is 32.9% higher and the water absorption is 3.5% lower than that of MRB sintered brick. MGS sintered bricks were prepared by mixing Yellow River sedimentary sand into MGB sintered bricks. The strength of MGS sintered bricks increased with the replacement rate of Yellow River sedimentary sand, and when the replacement rate of Yellow River sedimentary sand reached 16%, the strength of the MGS sintered bricks increased by 88.9%, and the water absorption rate was reduced by 4.6% compared with the MGB sintered bricks. The sintering mechanism had significant effects on the compressive strength, weathering resistance, and frost resistance of the sintered brick. The microwave sintering process has the characteristics of high efficiency, uniform heating, selective heating, and low thermal inertia, which can increase the compressive strength of MGS sintered brick by 4.6%, reduce the water absorption by 12.9%, shorten the sintering time by 43.6%, and improve the frost resistance. Full article

(This article belongs to the Section Civil Engineering)

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18 pages, 8275 KiB

Open AccessArticle

Performance Analysis of the YOLOv4 Algorithm for Pavement Damage Image Detection with Different Embedding Positions of CBAM Modules

by Li Li, Baihao Fang and Jie Zhu

Appl. Sci. 2022, 12(19), 10180; https://doi.org/10.3390/app121910180 - 10 Oct 2022

Cited by 9 | Viewed by 1697

Abstract

One of the most critical tasks for pavement maintenance and road safety is the rapid and correct identification and classification of asphalt pavement damages. Nowadays, deep learning networks have become the popular method for detecting pavement cracks, and there is always a need [...] Read more.

One of the most critical tasks for pavement maintenance and road safety is the rapid and correct identification and classification of asphalt pavement damages. Nowadays, deep learning networks have become the popular method for detecting pavement cracks, and there is always a need to further improve the accuracy and precision of pavement damage recognition. An improved YOLOv4-based pavement damage detection model was proposed in this study to address the above problems. The model improves the saliency of pavement damage by introducing the convolutional block attention module (CBAM) to suppress background noise and explores the influence of the embedding position of the CBAM module in the YOLOv4 model on the detection accuracy. The K-means++ algorithm was used to optimize the anchor box parameters to improve the target detection accuracy and form a high-performance pavement crack detection model called YOLOv4-3. The training and test sets were constructed using the same image data sources, and the results showed the mAP (mean average precision) of the improved YOLOv4-3 network was 2.96% higher than that before the improvement. The experiments indicate that embedding CBAM into the Neck module and the Head module can effectively improve the detection accuracy of the YOLOv4 model. Full article

(This article belongs to the Special Issue Applications of Artificial Intelligence to Improve Road Traffic Performance)

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21 pages, 1785 KiB

Open AccessArticle

A Multi-Classification Method Based on Optimized Binary Tree Mahalanobis-Taguchi System for Imbalanced Data

by Yefang Sun, Jun Gong and Yueyi Zhang

Appl. Sci. 2022, 12(19), 10179; https://doi.org/10.3390/app121910179 - 10 Oct 2022

Cited by 2 | Viewed by 1268

Abstract

Data imbalance is a common problem in classification tasks. The Mahalanobis-Taguchi system (MTS) has proven to be promising due to its lack of requirements for data distribution. The MTS is a binary classifier. However, multi-classification problems are more common in real life and [...] Read more.

Data imbalance is a common problem in classification tasks. The Mahalanobis-Taguchi system (MTS) has proven to be promising due to its lack of requirements for data distribution. The MTS is a binary classifier. However, multi-classification problems are more common in real life and the diversity of categories may further aggravate the difficulty of classifying imbalanced data. Imbalanced multi-classification has become an important research topic. To improve the performance of MTS in imbalanced multi-classification, we propose an algorithm called optimized binary tree MTS (Optimized BT-MTS). Mahalanobis space (MS) construction, feature selection, and threshold determination are incorporated in a unified classification framework, and joint optimization is carried out according to the principles of maximizing separability, signal-to-noise ratio, dimensionality reduction, and minimizing misclassification cost. Experimental results on several datasets show that the method can significantly reduce the overall misclassification cost and improve the performance of imbalanced data multi-classification. Full article

(This article belongs to the Section Computing and Artificial Intelligence)

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12 pages, 1371 KiB

Open AccessArticle

Effect of Medial-Lateral, Inferior-Superior, and Rotational Positions of Palms on Muscle Recruitment during the Push-Up Exercise

by Hamidreza Barnamehei, Gunarajulu Renganathan, Fatemeh Aflatounian, Samirasadat Fatemigarakani, Ava Maboudmanesh, Aidasadat Fatahzadeh, Aram Shaabani and Yuichi Kurita

Appl. Sci. 2022, 12(19), 10178; https://doi.org/10.3390/app121910178 - 10 Oct 2022

Cited by 3 | Viewed by 2326

Abstract

The goal of the present article is to compare neuromuscular activation patterns among medial-lateral, superior-inferior, and rotational positions of palms for 14 selective muscles during the push-up exercise. Muscle activity and kinematics information of fifteen males (68.35 ± 7.18 kg, 175 ± 3.40 [...] Read more.

The goal of the present article is to compare neuromuscular activation patterns among medial-lateral, superior-inferior, and rotational positions of palms for 14 selective muscles during the push-up exercise. Muscle activity and kinematics information of fifteen males (68.35 ± 7.18 kg, 175 ± 3.40 cm, 24.50 ± 7.50 years) were recorded by Myon Electromyographic (EMG) system and Vicon motion capture, respectively. EMG activity in the anterior deltoid, middle deltoid, posterior deltoid, infraspinatus, upper pectoralis major, middle pectoralis major, lower pectoralis major, latissimus dorsi, triceps lateral, triceps medial, biceps brachii, upper trapezius, middle trapezius, and lower trapezius was measured. According to the results, the narrow position of palms increased the infraspinatus, upper pectoralis major, triceps brachii (lateral and medial head), middle trapezius, and lower trapezius muscles, while the wide position of palms enhanced the lower pectoralis major muscle. Superior positions of palms enhanced the upper trapezius, while the inferior positions of palms increased the anterior deltoid, posterior deltoid, infraspinatus, biceps brachii, middle trapezius, lower trapezius, and pectoralis major (lower, middle, and upper) muscles. Internal positions of the palms increased all pectoralis major muscles (lower, middle, and upper), while external positions (lower, middle, and upper) enhanced the middle deltoid, latissimus dorsi, biceps brachii, middle trapezius, and lower trapezius muscles. The information about muscle activation during various types of push-ups can potentially help athletes, coaches, personal trainers, and clinicians to apply modified push-up exercises to make new systematic and useful exercise plans. Full article

(This article belongs to the Special Issue Biomechanical and Physiological Measurement in Sports)

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11 pages, 2692 KiB

Open AccessArticle

Modeling Undrained Shear Strength of Sensitive Alluvial Soft Clay Using Machine Learning Approach

by Mohamed B. D. Elsawy, Mohammed F. Alsharekh and Mahmoud Shaban

Appl. Sci. 2022, 12(19), 10177; https://doi.org/10.3390/app121910177 - 10 Oct 2022

Cited by 3 | Viewed by 4403

Abstract

Soft soils are commonly located in many regions near seas, oceans, and rivers all over the world. These regions are vital and attractive for population and governments development. Soft soil is classified as problematic soil owing to sustaining low shear strength and high [...] Read more.

Soft soils are commonly located in many regions near seas, oceans, and rivers all over the world. These regions are vital and attractive for population and governments development. Soft soil is classified as problematic soil owing to sustaining low shear strength and high settlement under structures. Constructing structures and/or infrastructures on soft soil is a considerable risk that needs great attention from structural engineers. The bearing capacity of structure foundations on soft soil depends mainly on their undrained shear strength. This soil feature strongly influences the selection of appropriate soil improvement methods. However, determining undrained shear strength is very difficult, costly, and time-consuming, especially for sensitive clay. Consequently, extracting undisturbed samples of sensitive clay faces several difficulties on construction sites. In this research, accurate field-tested data were fed to advanced machine learning models to predict the undrained shear strength of the sensitive clay to save hard effort, time, repeated laboratory testing, and costs. In this context, a dataset of 111 geotechnical testing points were collected based on laboratory and field examinations of the soil’s key features. These features included the water content, liquid limit, dry unit weight, plasticity index, consistency index, void ratio, specific gravity, and pocket penetration shear. Several machine learning algorithms were adopted to provide the soft clay modeling, including the linear, Gaussian process regression, ensemble and regression trees, and the support vector regression. The coefficient of determination was mainly used to assess the performance of each predictive model. The achieved results revealed that the support vector regression model attained the most accurate prediction for soil undrained shear strength. These outcomes lay the groundwork for evaluating soil shear strength characteristics in a practical, fast, and low-cost way. Full article

(This article belongs to the Special Issue The Application of Machine Learning in Geotechnical Engineering)

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36 pages, 9516 KiB

Open AccessArticle

Interdecadal Changes of the MERRA-2 Incoming Surface Solar Radiation (SSR) and Evaluation against GEBA & BSRN Stations

by Michael Stamatis, Nikolaos Hatzianastassiou, Marios Bruno Korras-Carraca, Christos Matsoukas, Martin Wild and Ilias Vardavas

Appl. Sci. 2022, 12(19), 10176; https://doi.org/10.3390/app121910176 - 10 Oct 2022

Cited by 4 | Viewed by 1821

Abstract

This study assesses and evaluates the 40-year (1980–2019) Modern-Era Retrospective Analysis for Research and Applications v.2 (MERRA-2) surface solar radiation (SSR) as well as its interdecadal changes (Δ(SSR)) against high quality reference surface measurements from 1397 Global Energy Balance Archive (GEBA) and 73 [...] Read more.

This study assesses and evaluates the 40-year (1980–2019) Modern-Era Retrospective Analysis for Research and Applications v.2 (MERRA-2) surface solar radiation (SSR) as well as its interdecadal changes (Δ(SSR)) against high quality reference surface measurements from 1397 Global Energy Balance Archive (GEBA) and 73 Baseline Surface Radiation Network (BSRN) stations. The study is innovative since MERRA-2 (Δ(SSR)) has never been evaluated in the past, while the MERRA-2 SSR fluxes themselves have not been evaluated in such large spatial scale, which is global here, and temporal basis, which counts 40-years. Other novelties of the study are the use of the highest quality BSRN stations, done for the first time in such an evaluation, as well as the use of a greater number of reference-GEBA stations than in other studies. Moreover, the assessment and evaluation in this study are largely based on SSR anomalies, while being done in depth, at spatial scales ranging from the local to global/hemispherical, and separately for land and ocean areas, and at temporal scales spanning intervals from decadal sub-periods to 40 years. Overall, the MERRA-2 deseasonalized SSR anomalies correlate well with either GEBA (R equal to 0.61) and BSRN (R equal to 0.62). The percentage of agreement between the sign of computed GEBA and MERRA-2 Δ(SSR) is equal to 63.4% and the corresponding percentage for MERRA-2 and BSRN is 50%. According to MERRA-2, strong and statistically significant positive Δ(SSR) (Brightening) is found over Europe, Central Africa, Mongolia, Mexico, Brazil, Argentina and some parts of the tropical oceans. In contrast, large and statistically significant negative Δ(SSR) (Dimming) occurs over the western Tropical Warm Pool, India, Southern East China, Amazonia, stratocumulus covered areas and some parts of oceans. MERRA-2 yields a dimming equal to −0.158 ± 0.005 W/m²/year over the globe from 1980 to 2019. This 40-year dimming, which occurred in both hemispheres, more over ocean than continental areas (−0.195 ± 0.006 and −0.064 ± 0.006 W/m²/year, respectively), underwent decadal scale variations. Full article

(This article belongs to the Special Issue Solar Radiation: Measurements and Modelling, Effects and Applications—Volume III)

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12 pages, 576 KiB

Open AccessArticle

Fast Sparse Bayesian Learning-Based Channel Estimation for Underwater Acoustic OFDM Systems

by Yong-Ho Cho

Appl. Sci. 2022, 12(19), 10175; https://doi.org/10.3390/app121910175 - 10 Oct 2022

Cited by 2 | Viewed by 1196

Abstract

Harsh underwater channels and energy constraints are the two critical issues of underwater acoustic (UWA) communications. To achieve a high channel estimation performance under a severe underwater channel, sparse Bayesian learning (SBL)-based channel estimation was adopted for UWA orthogonal frequency division multiplexing (OFDM) [...] Read more.

Harsh underwater channels and energy constraints are the two critical issues of underwater acoustic (UWA) communications. To achieve a high channel estimation performance under a severe underwater channel, sparse Bayesian learning (SBL)-based channel estimation was adopted for UWA orthogonal frequency division multiplexing (OFDM) systems. Accurate channel estimation can guarantee the successful reception of transmitted data and reduce retransmission occurrences, thereby, leading to energy-efficient communications. However, SBL-based algorithms have improved performances in iterative ways, which require high power consumption. In this paper, a fast SBL algorithm based on a weighted learning rule for hyperparameters is proposed for channel estimation in a UWA-OFDM system. It was shown via numerical analysis that the proposed weighted learning rule enables fast convergence and more accurate channel estimation simultaneously. Simulation results confirm that the proposed algorithm achieves higher accuracy in channel estimation with much fewer iteration numbers in comparison to conventional SBL-based methods for a time-varying UWA channel. Full article

(This article belongs to the Special Issue Underwater Acoustic Signal Processing)

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15 pages, 5968 KiB

Open AccessArticle

Effect of Grating Ruling Machine System Errors on Grating Spectral Performance

by Chao Yang and Xu Chen

Appl. Sci. 2022, 12(19), 10174; https://doi.org/10.3390/app121910174 - 10 Oct 2022

Cited by 1 | Viewed by 1622

Abstract

Grating groove functions scalar theory can describe the light source through the grating interference and diffraction effect of the physical phenomenon of splitting light. It can be used to represent the distribution of the complex amplitude of the illumination light source on the [...] Read more.

Grating groove functions scalar theory can describe the light source through the grating interference and diffraction effect of the physical phenomenon of splitting light. It can be used to represent the distribution of the complex amplitude of the illumination light source on the diffraction screen under the action of the diffraction grating and display the information on the diffracted light position and intensity distribution. As a result, the effect of groove error on the intensity of grating ghost lines and stray light is analyzed. This paper presents an energy solution and analysis of the grating periodic groove error utilizing the grating scalar diffraction theory. Based on this, the effect of the core components of the grating ruling machines, such as screw and worm gear, on the stray light and ghost line of the grating is analyzed. Finally, the random groove error is analyzed. The analysis results show that the worm gear error is an important reason for the appearance of ghost lines in the machine ruling grating, and the lead screw error and random grooving error are the main reasons for the stray light produced by the grating. We optimize the worm gear, lead screw, and error compensation system of the grating ruling machine to effectively improve the ruling quality of the grating. Full article

(This article belongs to the Special Issue State of the Art in Diffraction Grating: From Manufacturing to Spectroscopy Application)

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15 pages, 1788 KiB

Open AccessArticle

Differential Analysis of a Cryptographic Hashing Algorithm HBC-256

by Kunbolat Algazy, Kairat Sakan, Nursulu Kapalova, Saule Nyssanbayeva and Dilmukhanbet Dyusenbayev

Appl. Sci. 2022, 12(19), 10173; https://doi.org/10.3390/app121910173 - 10 Oct 2022

Cited by 1 | Viewed by 1574

Abstract

The article observes the new hashing algorithm HBC-256. The HBC-256 algorithm is based on the block cipher of the compression function CF (Compression Function) and produces a 256-bits hash value. Like any new cryptographic structure, the HBC-256 algorithm requires careful research process in [...] Read more.

The article observes the new hashing algorithm HBC-256. The HBC-256 algorithm is based on the block cipher of the compression function CF (Compression Function) and produces a 256-bits hash value. Like any new cryptographic structure, the HBC-256 algorithm requires careful research process in order to confirm its cryptographic properties, namely: pre-image resistance and resistance to collisions of the first and second order. As a result of the research, for the HBC-256 hashing algorithm differential properties of nonlinear elements (S-boxes) and various options for constructing round characteristics are considered. A hypothesis has been advanced about the existence of paired differences, which will make it possible to construct round characteristics for hashing and for the function of round keys generating. It is shown that even for the most optimal way of constructing chains of differences, the probability of finding correct pairs of texts is less than the probability of a complete enumeration of one 128-bit block of input data, which makes the method of differential cryptanalysis unsuitable for finding collisions. Full article

(This article belongs to the Section Electrical, Electronics and Communications Engineering)

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18 pages, 4740 KiB

Open AccessArticle

Electromagnetic Wave Scattering by a Multiple Core Model of Composite Cylindrical Wires at Oblique Incidence

by George S. Liodakis, Theodoros N. Kapetanakis, Melina P. Ioannidou, Anargyros T. Baklezos, Nikolaos S. Petrakis, Christos D. Nikolopoulos and Ioannis O. Vardiambasis

Appl. Sci. 2022, 12(19), 10172; https://doi.org/10.3390/app121910172 - 10 Oct 2022

Viewed by 1490

Abstract

A complex cylindrical structure consisting of a group of parallel stratified circular lossy dielectric cylinders, embedded in a dielectric circular cylindrical region and surrounded by unbounded dielectric space, is considered in this paper. The scattering of electromagnetic (EM) plane waves by the aforementioned [...] Read more.

A complex cylindrical structure consisting of a group of parallel stratified circular lossy dielectric cylinders, embedded in a dielectric circular cylindrical region and surrounded by unbounded dielectric space, is considered in this paper. The scattering of electromagnetic (EM) plane waves by the aforementioned configuration was studied; the EM waves impinged obliquely upon the structure and were arbitrarily polarized. The formulation used was based on the boundary-value approach coupled with the generalized separation of variables method. The EM field in each region of space was expanded in cylindrical wave-functions. Furthermore, the translational addition theorem of these functions was applied in order to match the EM field components on any cylindrical interface and enforce the boundary conditions. The end result of the analysis is an infinite set of linear algebraic equations with the wave amplitudes as unknowns. The system is solved by the truncation of series and unknowns and then matrix inversion; thus, we provide a semi-analytical solution for the scattered far-field and, as a consequence, for the scattering cross section of the complex cylindrical structure. The numerical results focus on calculations of the electric- and magnetic-field intensity of the far-field as well as of the total scattering cross section of several geometric configurations that fall within the aforementioned general structure. The effect of the geometrical and electrical characteristics of the structure on the scattered field was investigated. Specifically, the cylinders’ size and spacing, their conductivity and permittivity as well as the incidence direction were modified in order to probe how these variations are imprinted on scattering. Moreover, comparisons with previously published results, as well as convergence tests, were performed; all tests and comparisons proved to be successful. Full article

(This article belongs to the Special Issue Microwave/Millimeter Wave Circuits and Systems for Emerging Wireless Applications)

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17 pages, 3359 KiB

Open AccessArticle

Power System State Estimation Approach Considering Transmission Line Temperature

by Qingwen Xu, Hengxu Zhang, Yongji Cao, Hao Qin and Zhimin Gao

Appl. Sci. 2022, 12(19), 10171; https://doi.org/10.3390/app121910171 - 10 Oct 2022

Cited by 3 | Viewed by 1344

Abstract

The transmission line parameters vary with the change of temperature, which has a significant impact on power system state estimation (SE). Based on the theory of electro-thermal coordination (ETC), this paper proposes two ETC-SE approaches with the consideration of transmission line temperature. The [...] Read more.

The transmission line parameters vary with the change of temperature, which has a significant impact on power system state estimation (SE). Based on the theory of electro-thermal coordination (ETC), this paper proposes two ETC-SE approaches with the consideration of transmission line temperature. The heat balance equation (HBE) is combined with the conventional weighted least square SE for establishing an ETC-SE model. Moreover, an augmented Jacobian ETC-SE approach is developed by integrating the HBE into pseudo measurements and the line temperature into state vectors. The Jacobian matrix is augmented correspondingly and the partial differential coefficients of measurements to line temperature are provided, which enables to calculate line temperature and voltage phasors simultaneously. Furthermore, in order to accelerate the solving process, an improved two-step ETC-SE algorithm is proposed, in which the SE and temperature estimation are decoupled and solved via alternate iteration. The effectiveness of the proposed ETC-SE approaches is verified by the IEEE 14-, 39-, and 118-bus systems. The results show that the proposed ETC-SE approach is effective to reduce the calculation errors and possesses good convergence performance with varying environmental circumstances and ill-conditioned branches. Full article

(This article belongs to the Special Issue Control of Power Systems)

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15 pages, 593 KiB

Open AccessArticle

Virtual Reality Retooling Humanities Courses: Finance and Marketing Experience at a Czech University

by Lilla Koreňová, Petr Gurný, Jozef Hvorecký, Petr Lůžek and Petr Rozehnal

Appl. Sci. 2022, 12(19), 10170; https://doi.org/10.3390/app121910170 - 10 Oct 2022

Cited by 4 | Viewed by 1763

Abstract

Virtual reality environments (VRE) allow users to visualize both real-life and imaginary activities. For this reason, they make appropriate training fields at universities, too. However, the positive or negative effects of VRE are still a subject of research. There is a need to [...] Read more.

Virtual reality environments (VRE) allow users to visualize both real-life and imaginary activities. For this reason, they make appropriate training fields at universities, too. However, the positive or negative effects of VRE are still a subject of research. There is a need to verify methods of their deployment, student responses and the impact of VRE implementation. Science and medicine courses are frequently exploiting VRE, while their exploitation in humanities is much less frequent. In our paper, we describe and evaluate their application in finance and marketing courses. Both courses were designed and developed as part of a larger, potentially university-wide project. The courses were enriched by mazes including 3-D rooms with course content elements. Students could explore them and communicate with their lecturers and classmates. To allow anytime/anywhere access, the VRE does not require using any special interface. The finance course was organized as a pedagogical experiment with test and control groups. Due to organizational and scheduling reasons, the VRE in marketing served just as enrichment. At the end of the term, all students using VRE were given a questionnaire assessing their satisfaction. The majority expressed satisfaction. In the finance course, positive opinion was also supported by students’ improved grades. In total, 87.5% of students agreed that the application of VRE contributed to gaining knowledge. Based on the positive experience and outcomes, the university plans to expand and to intensify its VRE-supported education. Full article

(This article belongs to the Special Issue 3D Vision, Virtual Reality and Serious Games)

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17 pages, 2188 KiB

Open AccessArticle

Effectiveness of the Overtaking Ban for Heavy Vehicles on the Four-Lane Divided Highway in Different Weather Conditions

by Robert Rijavec, Rok Marsetič and Irena Strnad

Appl. Sci. 2022, 12(19), 10169; https://doi.org/10.3390/app121910169 - 10 Oct 2022

Viewed by 1584

Abstract

In many European countries and also in Slovenia, the highway network was rapidly built in order to reduce congestion and to increase the level of traffic safety on congested sections of the road network, thus enabling a higher level of service and accelerating [...] Read more.

In many European countries and also in Slovenia, the highway network was rapidly built in order to reduce congestion and to increase the level of traffic safety on congested sections of the road network, thus enabling a higher level of service and accelerating polycentric development. Unfortunately, traffic demand is growing over all limits, be it tourist car traffic or transit-heavy vehicle traffic. Thus, countries are forced to actively manage road freight traffic, which is present all year round. Accordingly, in Slovenia, permanent and timed restrictions were introduced for trucks regarding overtaking on highways. Overtaking is prohibited during the day but trucks are allowed to change lanes at night. It should be noted, however, that there may be circumstances that can restrict the normal travel of heavy vehicles in all lanes in one way or another, whether at night or during the day. We would like to convince highway traffic managers that weather-responsive adaptive traffic control could be more efficient when weather conditions are considered. This article presents an approach to simulate traffic flow on a short section of a two-lane unidirectional carriageway under various weather conditions. Using two scenarios for lane traffic control, i.e., with and without a truck overtaking ban, as examples, we show that knowledge of the traffic characteristics of each lane in different weather conditions is important for decision-making and for the timeliness of traffic management. We found that under certain traffic and weather conditions, prohibiting vehicles from overtaking with limited speed limits on four-lane divided highways or proper traffic lane control has a positive effect on the traffic fluency or available conditional capacity of the highway. To some extent, this confirms that the decision of the operator of the Slovenian highway system regarding the driving regime for heavy vehicles was correct. Through our research, we found that dynamic bans can be more effective when we include the dynamics of traffic demand, and environmental and weather conditions. Full article

(This article belongs to the Topic Intelligent Transportation Systems)

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14 pages, 2242 KiB

Open AccessArticle

PriRepVGG: Privacy-Preserving 3-Party Inference Framework for Image-Based Defect Detection

by Jiafu Liu, Zhiyuan Yao, Shirui Guo, Hongjun Xie and Genke Yang

Appl. Sci. 2022, 12(19), 10168; https://doi.org/10.3390/app121910168 - 10 Oct 2022

Cited by 1 | Viewed by 1104

Abstract

Image classification is widely used in industrial defect detection, medical diagnosis, social welfare, and other fields, in which privacy and security of models and data must be involved. For example, in diamond synthesis, the diamond substrate image annotation data and the defect detection [...] Read more.

Image classification is widely used in industrial defect detection, medical diagnosis, social welfare, and other fields, in which privacy and security of models and data must be involved. For example, in diamond synthesis, the diamond substrate image annotation data and the defect detection model are of value for conservation. Based on ensuring inference efficiency and the security of these private data intellectual property, the 3-party secure inference based on secure multi-party computation (MPC) can be adopted. MPC allows parties to use neural networks while preserving their input privacy for collaborative computing, but it will lead to huge communication and memory consumption. This paper propose PriRepVGG, a lightweight privacy-preserving image-based defect detection framework for 3-party. In this work, firstly, This work optimized the division and added an AdaptiveAvgpool layer in MPC framework FALCON; then, This work ported the inference architecture of the RegVGG network into FALCON creatively. Our work applied PriRepVGG to the secure inference of the diamond substrates defect detection under the data server, model server, and compute server settings, which can be carried out in batches with a low misjudgment rate and verify the feasibility of image-based secure inference with a lightweight network in an industrial case under MPC. Full article

(This article belongs to the Special Issue Multi-Agent System Control: Recent Theories and Applications)

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20 pages, 7769 KiB

Open AccessArticle

Deep Learning Based Detector YOLOv5 for Identifying Insect Pests

by Iftikhar Ahmad, Yayun Yang, Yi Yue, Chen Ye, Muhammad Hassan, Xi Cheng, Yunzhi Wu and Youhua Zhang

Appl. Sci. 2022, 12(19), 10167; https://doi.org/10.3390/app121910167 - 10 Oct 2022

Cited by 52 | Viewed by 8950

Abstract

Insect pests are a major element influencing agricultural production. According to the Food and Agriculture Organization (FAO), an estimated 20–40% of pest damage occurs each year, which reduces global production and becomes a major challenge to crop production. These insect pests cause sooty [...] Read more.

Insect pests are a major element influencing agricultural production. According to the Food and Agriculture Organization (FAO), an estimated 20–40% of pest damage occurs each year, which reduces global production and becomes a major challenge to crop production. These insect pests cause sooty mold disease by sucking the sap from the crop’s organs, especially leaves, fruits, stems, and roots. To control these pests, pesticides are frequently used because they are fast-acting and scalable. Due to environmental pollution and health awareness, less use of pesticides is recommended. One of the salient approaches could be to reduce the wide use of pesticides by spraying on demand. To perform spot spraying, the location of the pest must first be determined. Therefore, the growing population and increasing food demand emphasize the development of novel methods and systems for agricultural production to address environmental concerns and ensure efficiency and sustainability. To accurately identify these insect pests at an early stage, insect pest detection and classification have recently become in high demand. Thus, this study aims to develop an object recognition system for the detection of crops damaging insect pests and their classification. The current work proposes an automatic system in the form of a smartphone IP- camera to detect insect pests from digital images/videos to reduce farmers’ reliance on pesticides. The proposed approach is based on YOLO object detection architectures including YOLOv5 (n, s, m, l, and x), YOLOv3, YOLO-Lite, and YOLOR. For this purpose, we collected 7046 images in the wild under different illumination and background conditions to train the underlying object detection approaches. We trained and test the object recognition system with different parameters from scratch. The eight models are compared and analyzed. The experimental results show that the average precision (AP@0.5) of the eight models including YOLO-Lite, YOLOv3, YOLOR, and YOLOv5 with five different scales (n, s, m, l, and x) reach 51.7%, 97.6%, 96.80%, 83.85%, 94.61%, 97.18%, 97.04%, and 98.3% respectively. The larger the model, the higher the average accuracy of the detection validation results. We observed that the YOLOv5x model is fully functional and can correctly identify the twenty-three species of insect pests at 40.5 milliseconds (ms). The developed model YOLOv5x performs the state-of-the-art model with an average precision value of (mAP@0.5) 98.3%, (mAP@0.5:0.95) value of 79.8%, precision of 94.5% and a recall of 97.8%, and F1-score with 96% on our IP-23 dataset. The results show that the system works efficiently and was able to correctly detect and identify insect pests, which can be employed for realistic application while farming. Full article

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23 pages, 2172 KiB

Open AccessArticle

Application of Deep Learning Techniques and Bayesian Optimization with Tree Parzen Estimator in the Classification of Supply Chain Pricing Datasets of Health Medications

by David Opeoluwa Oyewola, Emmanuel Gbenga Dada, Temidayo Oluwatosin Omotehinwa, Onyeka Emebo and Olugbenga Oluseun Oluwagbemi

Appl. Sci. 2022, 12(19), 10166; https://doi.org/10.3390/app121910166 - 10 Oct 2022

Cited by 8 | Viewed by 3046

Abstract

From the development and sale of a product through its delivery to the end customer, the supply chain encompasses a network of suppliers, transporters, warehouses, distribution centers, shipping lines, and logistics service providers all working together. Lead times, bottlenecks, cash flow, data management, [...] Read more.

From the development and sale of a product through its delivery to the end customer, the supply chain encompasses a network of suppliers, transporters, warehouses, distribution centers, shipping lines, and logistics service providers all working together. Lead times, bottlenecks, cash flow, data management, risk exposure, traceability, conformity, quality assurance, flaws, and language barriers are some of the difficulties that supply chain management faces. In this paper, deep learning techniques such as Long Short-Term Memory (LSTM) and One Dimensional Convolutional Neural Network (1D-CNN) were adopted and applied to classify supply chain pricing datasets of health medications. Then, Bayesian optimization using the tree parzen estimator and All K Nearest Neighbor (AllkNN) was used to establish the suitable model hyper-parameters of both LSTM and 1D-CNN to enhance the classification model. Repeated five-fold cross-validation is applied to the developed models to predict the accuracy of the models. The study showed that the combination of 1D-CNN, AllkNN, and Bayesian optimization (1D-CNN+AllKNN+BO) outperforms other approaches employed in this study. The accuracy of the combination of 1D-CNN, AllkNN, and Bayesian optimization (1D-CNN+AllKNN+BO) from one-fold to 10-fold, produced the highest range between 61.2836% and 63.3267%, among other models. Full article

(This article belongs to the Special Issue Artificial Intelligence for Health and Well-Being)

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14 pages, 2820 KiB

Open AccessArticle

Biomechanical Evaluation of a Novel Expandable Vertebral Augmentation System Using Human Cadaveric Vertebrae

by Ming-Kai Hsieh, Wen-Jer Chen, Mel S. Lee, Sheng-Yu Lin, Mu-Yi Liu, De-Mei Lee and Ching-Lung Tai

Appl. Sci. 2022, 12(19), 10165; https://doi.org/10.3390/app121910165 - 10 Oct 2022

Cited by 1 | Viewed by 1348

Abstract

Unacceptable sagittal alignment and cement leakage are major concerns of percutaneous vertebroplasty when treating patients with painful vertebral osteoporotic compression fractures. To maintain the restored vertebral height and reduce the reliance on cement as the major stabilizer, an expandable vertebral augment system (EVA [...] Read more.

Unacceptable sagittal alignment and cement leakage are major concerns of percutaneous vertebroplasty when treating patients with painful vertebral osteoporotic compression fractures. To maintain the restored vertebral height and reduce the reliance on cement as the major stabilizer, an expandable vertebral augment system (EVA^®) made of titanium alloy consisting of a rigid tube encased by a barrel with an anterior expansion mechanism was developed. The aim of the current study was to determine whether this novel design is as effective as existing procedures in terms of height restoration and biomechanical performance. Eight osteoporotic vertebrae (T12-L3) confirmed by dual-energy X-ray absorptiometry from two fresh-frozen human cadavers (70- and 72-year-old females) were used. Twenty-five percent reduced anterior wedge vertebral compression fractures were created using a material testing machine. Four randomized specimens were augmented with EVA^® (Chang Gu Biotechnology Co. Ltd., Taipei city, Taiwan), and another four randomized specimens were augmented with OsseoFix^® (AlphaTec Spine Inc., Carlsbad, CA, USA). The implant size and cement volume were controlled. The anterior vertebral body height (VBH) ratio and pre/postaugmented ultimate strength and stiffness were measured and compared. The mean anterior VBH restoration ratio was 8.54% in the EVA^® group and 8.26% in the OsseoFix^® groups. A significant difference from augmentation was measured in both groups (p < 0.05), but there was no significant difference between the EVA^® and OsseoFix^® groups in anterior VBH restoration. The ultimate strengths of the EVA^® and OsseoFix^® groups were 6071.4 ± 352.6 N and 6262.9 ± 529.2 N, respectively, both of which were statistically significantly higher than that of the intact group (4589.9 ± 474.6 N) (p < 0.05). The stiffnesses of the EVA^®, OsseoFix^®, and intact groups were 1087.2 ± 176.9, 1154.9 ± 168.9, and 1637.3 ± 340.8 N/mm, respectively, indicating that the stiffness was significantly higher in the intact group than in both the EVA^® and OsseoFix^® groups (p < 0.05). No significant differences were observed between the two augmentation procedures in height restoration or ultimate strength and stiffness. This novel EVA^® system showed comparable height restoration and biomechanical performance to those of existing implants for human cadaveric osteoporotic compression fractures. Potential advantages of preventing cement posterior leakage and promoting cement interdigitation are expected with this ameliorated design. Full article

(This article belongs to the Section Applied Biosciences and Bioengineering)

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14 pages, 6332 KiB

Open AccessArticle

A Theoretical Proposal for an Actively Controlled Ultra-Wideband Absorber Based on Vanadium Dioxide Hybrid Metamaterials

by Ubaid Ur Rahman Qureshi, Muhammad Ismail Khan and Bin Hu

Appl. Sci. 2022, 12(19), 10164; https://doi.org/10.3390/app121910164 - 10 Oct 2022

Cited by 14 | Viewed by 1472

Abstract

In this study, an ultra-wideband actively tunable terahertz absorber composed of four identical arc-shaped structures made of phase transition material vanadium dioxide (VO₂) is presented. A metal ground plane is placed at the bottom and an insulating spacer (quartz) as the [...] Read more.

In this study, an ultra-wideband actively tunable terahertz absorber composed of four identical arc-shaped structures made of phase transition material vanadium dioxide (VO₂) is presented. A metal ground plane is placed at the bottom and an insulating spacer (quartz) as the middle dielectric layer. Simulation results demonstrate 90% absorption with a broad bandwidth spanning 3 THz (2.7 THz–5.7 THz) under normal incidence. The proposed structure transforms from a reflector to an absorber by changing the conductivity from 200 S/m to 2 × 10⁵ S/m; the absorbance at peak frequencies can be consistently tuned from 4% to 100%. Absorption spectra demonstrate that the polarization angle does not affect the response of the proposed structure. Power loss density (PLD) and impedance-matching theory are further analyzed to learn more about the physical origin of ultra-wide absorption. The ultra-wide operating bandwidth, high absorption efficiency, active tunability, and independence of polarization make the proposed structure an excellent candidate for integration into profound THz applications such as sensors, modulators, and optic-electro switches. Full article

(This article belongs to the Section Nanotechnology and Applied Nanosciences)

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15 pages, 1875 KiB

Open AccessArticle

Analysis of Road Sign-Related Factors Affecting Driving Safety with Respect to City Size

by Woo Chul Choi and Kyu Soo Chong

Appl. Sci. 2022, 12(19), 10163; https://doi.org/10.3390/app121910163 - 10 Oct 2022

Cited by 3 | Viewed by 6092

Abstract

With the increasing popularity of digital navigation systems and smartphones, the role of road signs during driving is gradually diminishing. However, owing to the inaccessibility of the technology to certain portions of the population, e.g., the elderly, and the risk of failure of [...] Read more.

With the increasing popularity of digital navigation systems and smartphones, the role of road signs during driving is gradually diminishing. However, owing to the inaccessibility of the technology to certain portions of the population, e.g., the elderly, and the risk of failure of communication networks, road signs continue to be an essential public tool to ensure driving safety. Although some research has been conducted on road sign-related topics, e.g., road sign recognition and image analysis, the comprehensive safety of road sign functions has not yet been researched. Accordingly, this study analyzed the factors of road signs affecting driving safety based on ordinal logistic regression analysis and derived their implications through a public survey. To improve driving safety, it is necessary to improve the intuitiveness of guide information (Daytime recognition (odds ratio): 1.547, Understanding of guide information: 1.222), select user’s necessary information (Sufficiency of guide information: 1.449) and provide variable information (Real-time guidance according to situation), establish a road guide system for various future mobility modes (Customized guidance for various forms of mobility: 1.112), and link and integrate with surrounding road facilities (Location/frequency adequacy: 1.128, Integrated installation of road facilities: 1.116). Full article

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11 pages, 2268 KiB

Open AccessArticle

Electrical and Optical Properties of Laser-Induced Structural Modifications in PbSe Films

by Anastasiia A. Olkhova, Alina A. Patrikeeva and Maksim M. Sergeev

Appl. Sci. 2022, 12(19), 10162; https://doi.org/10.3390/app121910162 - 10 Oct 2022

Cited by 4 | Viewed by 1547

Abstract

PbSe chalcogenide films are widely used as photosensitive elements in gas analysis devices. High absorption in the IR spectrum region and low electrical resistance are important characteristics. Continuous laser radiation exposure of films in the near UV range makes it possible to achieve [...] Read more.

PbSe chalcogenide films are widely used as photosensitive elements in gas analysis devices. High absorption in the IR spectrum region and low electrical resistance are important characteristics. Continuous laser radiation exposure of films in the near UV range makes it possible to achieve the desired characteristics, replacing oven heat treatment in the technological process. In the considered laser technology, PbSe films are subjected to photothermal action by a spot of focused radiation in the progressive scanning mode. In this work, changes in the optical and electrical film properties were studied, and the mechanism of structural laser modification was also considered. Full article

(This article belongs to the Special Issue Holographic Technologies: Theory and Practice)

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26 pages, 1629 KiB

Open AccessReview

The Role of Iron in DNA and Genomic Instability in Cancer, a Target for Iron Chelators That Can Induce ROS

by Andrew Carter, Seth Racey and Stephany Veuger

Appl. Sci. 2022, 12(19), 10161; https://doi.org/10.3390/app121910161 - 10 Oct 2022

Cited by 7 | Viewed by 3009

Abstract

Iron is a key metal involved in several biological processes such as DNA replication and repair, cellular proliferation and cell cycle regulation. Excess volumes of labile iron are toxic and can lead to the production of ROS (reactive oxygen species) via Fenton chemistry. [...] Read more.

Iron is a key metal involved in several biological processes such as DNA replication and repair, cellular proliferation and cell cycle regulation. Excess volumes of labile iron are toxic and can lead to the production of ROS (reactive oxygen species) via Fenton chemistry. Due to this reactive nature, it can contribute to DNA damage and genomic instability. Therefore, excess iron in the labile iron pool is associated with cancer, which has made the labile iron pool a crucial target for anticancer therapy by targeting iron. This iron can be incorporated into essential enzymes such as ribonucleotide reductase (RnR). Over several decades of research, iron chelators function as more than just RnR inhibitors. Indeed, a plethora of iron chelator mechanisms can result in therapeutic properties that can target critical steps of cancer cells’ aberrant biological abilities such as proliferation, migration and metastasis. One such mechanism is the production of redox-active complexes that can produce toxic levels of ROS in cancer cells. Cancer cells are potentially more susceptible to ROS production or modulation of antioxidant levels. Understanding iron metabolism is vital in targeting cancer. For instance, Fe-S clusters have recently been shown to play crucial roles in cell signalling by ROS through their incorporation into essential DNA replication and repair enzymes. ROS can also degrade Fe-S clusters. Iron chelators that produce toxic levels of ROS, therefore, could also target Fe-S centres. Thus, the design of iron chelators is important, as this can determine if it will participate in redox cycling and produce ROS or if it is solely used to remove iron. This review focuses on alterations in cancer iron metabolism, iron’s role in genomic stability and how the design of chelators can use Fenton chemistry to their advantage to cause DNA damage in cancer cells and potentially inhibit Fe-S centres. Full article

(This article belongs to the Special Issue Recent Advances in Biological Science and Technology)

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19 pages, 5174 KiB

Open AccessArticle

Fuel Consumption Reduction and Efficiency Improvement in Urban Street Sweeper Using Power Split with Lockup Clutch Transmission

by Danilo D’Andrea, Giacomo Risitano and Fabio Alberti

Appl. Sci. 2022, 12(19), 10160; https://doi.org/10.3390/app121910160 - 10 Oct 2022

Viewed by 1667

Abstract

The aim of this work is to design a power split transmission for an urban street sweeper in order to reduce fuel consumption. The design process starts with the comparison between a hydrostatic and a hydromechanical power split transmission. Both transmissions have been [...] Read more.

The aim of this work is to design a power split transmission for an urban street sweeper in order to reduce fuel consumption. The design process starts with the comparison between a hydrostatic and a hydromechanical power split transmission. Both transmissions have been tested through an acceleration test considering 30, 50, 70 and 100 percent of the rated engine power. The results of both models developed in the Simcenter Amesim^TM environment show that the power split transmission presents a higher efficiency, which justifies the adoption of this type of transmission with respect to the hydrostatic system. Then, a pure mechanical gear is added to the base concept of the power split transmission. The mechanical gear is managed by a lockup clutch, which can be engaged during the working phase of the street sweeper, similar to an adaptive cruise control. In this case, both transmissions are tested through a regulated cycle, UNI-EN 151429-2, highlighting the advantage of using a pure mechanical branch. At the end, both transmissions are tested with a driving cycle acquired through an experimental setup consisting of a control unit, a GPS and a tablet for the monitoring of the speed profile. The results show that the adoption of a lockup clutch allows an increase in the system efficiency during the working phase, hence reducing the average fuel consumption during the mission test. Full article

(This article belongs to the Special Issue Future Transportation)

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