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Appl. Sci., Volume 13, Issue 3 (February-1 2023) – 798 articles

Cover Story (view full-size image): Many applications require the placement of electronic equipment in open spaces exposed to relentless environmental “attacks”. These devices, most often interconnected with different kinds of sensors, need to transmit collected data sometimes over long distances to control centers and even receive commands regarding their operation. Enclosure of the whole equipment in the right material ensures protection from component failure and thus device malfunction, but in many cases, it is too time-consuming and costly to be addressed, e.g., when the device is placed in remote areas at high elevations. The proposed shielding involves DGEBF epoxy reinforced with ZnO (nano)rods at 0.5 wt% providing protection against prolonged artificial weathering environment exposure, not only without compromising, but even enhancing the composite’s dielectric behavior in the VHF/early UHF frequency range. View this paper
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13 pages, 4261 KiB  
Article
β-Phosphonated Glycine Pendant Groups Grafted on Styrene-6.7% Divinylbenzene Copolymers: Synthesis and Their Application as Photocatalysts
by Adriana Popa, Laura Cocheci, Lavinia Lupa, Aniela Pop and Aurelia Visa
Appl. Sci. 2023, 13(3), 2025; https://doi.org/10.3390/app13032025 - 3 Feb 2023
Cited by 2 | Viewed by 1583
Abstract
Environmental pollution from organic contaminants caused by textile dyeing is a real danger. Wastewater from the textile industry has high organic loads, as well as dyes and chemical compounds used in their preparation. Among the azo dyes, Congo red (CR) dye is widely [...] Read more.
Environmental pollution from organic contaminants caused by textile dyeing is a real danger. Wastewater from the textile industry has high organic loads, as well as dyes and chemical compounds used in their preparation. Among the azo dyes, Congo red (CR) dye is widely used as a model in the experimental studies of textile wastewater treatment. Heterogeneous photocatalysis consists of UV or VIS light irradiation of various types of organic compounds in water in the presence of a solid catalyst; it is considered an important technique for the purification and reuse of aqueous effluents. In the present study, two novel compounds of β-phosphonate-type glycine pendant groups grafted on S-DVB copolymer were used for the decontamination of Congo red dye polluted water. They were characterized by FTIR spectroscopy, scanning electron microscopy, EDX spectroscopy, thermogravimetric analysis and UV-VIS spectroscopy. By using 25 mg/L initial concentration of Congo red dye and a catalyst concentration of 1 g/L and 240 min of irradiation, a photocatalysis efficiency of 98.6% in the case of [(diethyl)(phosphono)methylene]glycine pendant groups grafted on styrene-6.7% divinylbenzene copolymer (EthylAmAcid material), and of 83.1% in the case of [(dibenzyl)(phosphono)methylene]glycine pendant groups grafted on styrene-6.7% divinylbenzene copolymer (BenzylAmAcid material), respectively, was achieved. Full article
(This article belongs to the Special Issue New Trends in Functional and Multifunctional Advanced Materials)
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17 pages, 4581 KiB  
Article
Applicable Conditions of Room-and-Pillar Mining Goaf Treatment Methods under a Traffic Load
by Fajin Zu, Chao Du, Chunpeng Han, Lanyu Xu and Qiuying Peng
Appl. Sci. 2023, 13(3), 2024; https://doi.org/10.3390/app13032024 - 3 Feb 2023
Cited by 2 | Viewed by 1513
Abstract
The disturbance depth of traffic load has a direct impact on the stability of a room-and-pillar mining goaf. To quantitatively calculate the relationship between the traffic load disturbance depth and influencing factors, 49 groups of horizontal combinations of different influencing parameters are designed [...] Read more.
The disturbance depth of traffic load has a direct impact on the stability of a room-and-pillar mining goaf. To quantitatively calculate the relationship between the traffic load disturbance depth and influencing factors, 49 groups of horizontal combinations of different influencing parameters are designed in this study, based on the orthogonal experimental design method. Midas GTS is used to simulate and obtain the corresponding traffic load disturbance depth data. A multivariate linear regression analysis of the traffic load disturbance depth is conducted, and a regression formula for calculating the traffic load disturbance depth is established. According to the traffic load disturbance depth, goaf depth, and the stability of the roof, coal pillar, and base plate under traffic load conditions, a judgment flow of the room-and-pillar mining goaf treatment method under traffic load conditions is established, and it is applied to the reconstruction and expansion project of the Jixi section of the Dan-A national highway. The results show that a geogrid can be used for treatment purposes when the traffic load disturbance depth is 1.5 times lower than the depth of the room-and-pillar mining goaf, or when the traffic load disturbance depth is 1.5 times greater than the depth of the room-and-pillar mining goaf but the roof, coal pillar, and base plate are stable. Additionally, grouting is needed for treatment in other cases. The results of this study can provide a scientific basis for the selection of treatment methods for room-and-pillar mining goafs underlying highways in the future. The results are of great significance in the field of engineering for the safety measures concerning highway room-and-pillar mining goafs. Full article
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14 pages, 5405 KiB  
Article
Clogging Prevention of Slurry–Earth Pressure Balance Dual-Mode Shield in Composed Strata with Medium–Coarse Sand and Argillaceous Siltstone
by Zhao Yang, Pengfei Liu, Peishuai Chen, Shuchen Li and Fuquan Ji
Appl. Sci. 2023, 13(3), 2023; https://doi.org/10.3390/app13032023 - 3 Feb 2023
Cited by 5 | Viewed by 1792
Abstract
The slurry–earth pressure balance dual-mode shield has an earth pressure balance (EPB) and slurry shield functions. Based on a shield tunnel project of Guangzhou Metro Line 12 in China, this study investigates the clogging prevention of a slurry–earth pressure balance dual-mode shield in [...] Read more.
The slurry–earth pressure balance dual-mode shield has an earth pressure balance (EPB) and slurry shield functions. Based on a shield tunnel project of Guangzhou Metro Line 12 in China, this study investigates the clogging prevention of a slurry–earth pressure balance dual-mode shield in a composed stratum with medium–coarse sand and argillaceous siltstone. The results show that the slurry mode was not applicable to the composed stratum with medium–coarse sand and argillaceous siltstone. The excavated soil accumulated easily in the slurry chamber, causing shield clogging. The total thrust force of the shield increased significantly, the tunneling speed gradually decreased to 0, and the torque of the cutterhead increased slightly after the slurry shield was clogged. The fluctuation in the total thrust force, the cutterhead torque, and the tunneling speed also increased significantly. The EPB mode is recommended for composed strata with medium–coarse sand and argillaceous siltstone. The dispersible foam agent and water needed to be used for soil conditioning. The injection amount of foam and water was determined according to the status of the mud discharged by the screw conveyor. Water absorption can be used to characterize the water absorption capacity of particles larger than 0.15 mm. The ideal soil state was that the consistency index of the particles smaller than 0.15 mm was less than 0.5 to prevent the EPB shield from clogging. The water absorption of soil with a particle larger than 0.15 mm should be removed when calculating the consistency index. Full article
(This article belongs to the Special Issue Advances in Sustainable Geotechnical Engineering)
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22 pages, 6672 KiB  
Article
Theoretical Investigation of Mesh Relationship and Mesh Stiffness of Internal Spur Gears with Tooth Wear
by Yanan Wang, Keyuan Li, Baijie Qiao, Zhixian Shen and Xuefeng Chen
Appl. Sci. 2023, 13(3), 2022; https://doi.org/10.3390/app13032022 - 3 Feb 2023
Cited by 1 | Viewed by 2060
Abstract
The internal gear is part of the planetary and epicyclic gear pairs in the transmission system of the helicopter. Gear tooth wear is one of the most usual gear failures. This paper establishes an analytical model to evaluate the influence of tooth wear [...] Read more.
The internal gear is part of the planetary and epicyclic gear pairs in the transmission system of the helicopter. Gear tooth wear is one of the most usual gear failures. This paper establishes an analytical model to evaluate the influence of tooth wear on the mesh relationship. A new mesh relationship can be derived for internal spur gears with tooth wear by the proposed analytical model. Consequently, using the new mesh relationship, the two most important meshing excitations, mesh stiffness and unloaded static transmission error (USTE), are quantitatively evaluated for the internal gear with tooth wear. The results indicate that tooth wear mainly affects the meshing ranges of single-tooth and double-teeth in mesh stiffness, rather than its amplitude. Additionally, the amplitudes of USTE increase with the increasing wear depth. Finally, this study can offer a foundation for the dynamic modeling and fault diagnosis of internal spur gears with wear faults. Full article
(This article belongs to the Special Issue Signal Analysis and Fault Diagnosis in Mechanical Engineering)
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17 pages, 1643 KiB  
Article
Decision Framework for Predictive Maintenance Method Selection
by Wieger Tiddens, Jan Braaksma and Tiedo Tinga
Appl. Sci. 2023, 13(3), 2021; https://doi.org/10.3390/app13032021 - 3 Feb 2023
Cited by 2 | Viewed by 3954
Abstract
Many asset owners and maintainers have the ambition to better predict the future state of their equipment to make timely and better-informed maintenance decisions. Although many methods to support high-level maintenance policy selection are available, practitioners still often follow a costly trial-and-error process [...] Read more.
Many asset owners and maintainers have the ambition to better predict the future state of their equipment to make timely and better-informed maintenance decisions. Although many methods to support high-level maintenance policy selection are available, practitioners still often follow a costly trial-and-error process in selecting the most suitable predictive maintenance method. To address the lack of decision support in this process, this paper proposes a framework to support asset owners in selecting the optimal predictive maintenance method for their situation. The selection framework is developed using a design science process. After exploring common difficulties, a set of solutions is proposed for these identified problems, including a classification of the various maintenance methods, a guideline for defining the ambition level for the maintenance process, and a classification of the available data types. These elements are then integrated into a framework that assists practitioners in selecting the optimal maintenance approach. Finally, the proposed framework is successfully tested and demonstrated using four industrial case studies. It can be concluded that the proposed classifications of ambition levels, data types and types of predictive maintenance methods clarify and accelerate the complex selection process considerably. Full article
(This article belongs to the Special Issue Technical Diagnostics and Predictive Maintenance)
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21 pages, 8383 KiB  
Article
Bolt Loosening Detection Using Key-Point Detection Enhanced by Synthetic Datasets
by Qizhe Lu, Yicheng Jing and Xuefeng Zhao
Appl. Sci. 2023, 13(3), 2020; https://doi.org/10.3390/app13032020 - 3 Feb 2023
Cited by 3 | Viewed by 3082
Abstract
Machine vision based on deep learning is gaining more and more applications in structural health monitoring (SHM) due to the rich information that can be achieved in the images. Bolts are widely used in the connection of steel structures, and their loosening can [...] Read more.
Machine vision based on deep learning is gaining more and more applications in structural health monitoring (SHM) due to the rich information that can be achieved in the images. Bolts are widely used in the connection of steel structures, and their loosening can compromise the safety of steel structures and lead to serious accidents. Therefore, this paper proposes a method for the automatic detection of the bolt loosening angle based on the latest key point detection technology using machine vision and deep learning. First, we built a virtual laboratory in Unreal Engine5 that could automatically label and generate synthetic datasets, and the datasets with bolts were collected. Second, the datasets were trained using the YOLOv7-pose framework, and the resulting model was able to accurately detect key points of bolts in images obtained under different angles and lighting conditions. Third, a bolt loosening angle calculation method was proposed according to the detected key points and the position relationship between neighboring bolts. Our results demonstrate that the proposed method is effective at detecting the bolt loosening angle and that the use of synthetic datasets significantly improves the efficiency of datasets establishment while also improving the performance of model training. Full article
(This article belongs to the Special Issue Machine Learning–Based Structural Health Monitoring)
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17 pages, 2928 KiB  
Article
Panoramic Digital Image Correlation for 360-Deg Full-Field Displacement Measurement
by Yiran Li, Dong Zhao, Xueyi Ma, Jianzhong Zhang and Jian Zhao
Appl. Sci. 2023, 13(3), 2019; https://doi.org/10.3390/app13032019 - 3 Feb 2023
Cited by 2 | Viewed by 1567
Abstract
In full-field 3D displacement measurement, stereo digital image correlation (Stereo-DIC) has strong capabilities. However, as a result of difficulties with stereo camera calibration and surface merging, 360-deg panoramic displacement measurements remain a challenge. This paper proposes a panoramic displacement field measurement method in [...] Read more.
In full-field 3D displacement measurement, stereo digital image correlation (Stereo-DIC) has strong capabilities. However, as a result of difficulties with stereo camera calibration and surface merging, 360-deg panoramic displacement measurements remain a challenge. This paper proposes a panoramic displacement field measurement method in order to accurately measure the shape and panoramic displacement field of complex shaped objects with natural textures. The proposed method is based on the robust subset-based DIC algorithm and the well-known Zhang’s calibration method to reconstruct the 3D shape and estimate the full-field displacements of a complex surface from multi-view stereo camera pairs. The method is used in the determination of the scale factor of the 3D reconstructed surface and the stitching of multiple 3D reconstructed surfaces with the aid of the laser point cloud data of the object under test. Based on a discussion of the challenges faced by panoramic DIC, this paper details the proposed solution and describes the specific algorithms implemented. The paper tests the performance of the proposed method using an experimental system with a 360-deg six camera setup. The system was evaluated by measuring the rigid body motion of a cylindrical log sample with known 3D point cloud data. The results confirm that the proposed method is able to accurately measure the panoramic shape and full-field displacement of objects with complex morphologies. Full article
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20 pages, 2314 KiB  
Article
Timed-SAS: Modeling and Analyzing the Time Behaviors of Self-Adaptive Software under Uncertainty
by Deshuai Han, Yanping Cai, WenJie Chen, Zhigao Cui and Aihua Li
Appl. Sci. 2023, 13(3), 2018; https://doi.org/10.3390/app13032018 - 3 Feb 2023
Cited by 1 | Viewed by 1513
Abstract
Self-adaptive software (SAS) is gaining in popularity as it can handle dynamic changes in the operational context or in itself. Time behaviors are of vital importance for SAS systems, as the self-adaptation loops bring in additional overhead time. However, early modeling and quantitative [...] Read more.
Self-adaptive software (SAS) is gaining in popularity as it can handle dynamic changes in the operational context or in itself. Time behaviors are of vital importance for SAS systems, as the self-adaptation loops bring in additional overhead time. However, early modeling and quantitative analysis of time behaviors for the SAS systems is challenging, especially under uncertainty environments. To tackle this problem, this paper proposed an approach called Timed-SAS to define, describe, analyze, and optimize the time behaviors within the SAS systems. Concretely, Timed-SAS: (1) provides a systematic definition on the deterministic time constraints, the uncertainty delay time constraints, and the time-based evaluation metrics for the SAS systems; (2) creates a set of formal modeling templates for the self-adaptation processes, the time behaviors and the uncertainty environment to consolidate design knowledge for reuse; and (3) provides a set of statistical model checking-based quantitative analysis templates to analyze and verify the self-adaptation properties and the time properties under uncertainty. To validate its effectiveness, we presented an example application and a subject-based experiment. The results demonstrated that the Timed-SAS approach can effectively reduce modeling and verification difficulties of the time behaviors, and can help to optimize the self-adaptation logic. Full article
(This article belongs to the Topic Software Engineering and Applications)
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14 pages, 1613 KiB  
Article
Revamping Fluid Catalytic Cracking Unit, and Optimizing Catalyst to Process Heavier Feeds
by Dicho Stratiev, Mihail Ivanov, Ivan Chavdarov, Georgi Argirov and Giulia Strovegli
Appl. Sci. 2023, 13(3), 2017; https://doi.org/10.3390/app13032017 - 3 Feb 2023
Cited by 6 | Viewed by 2857
Abstract
H-Oil gas oils have a higher density and higher nitrogen content, and consequently much lower reactivity than straight-run vacuum gas oils during fluid catalytic cracking (FCC). The conversion of H-Oil gas oils observed in a laboratory catalytic cracking unit at constant operating conditions [...] Read more.
H-Oil gas oils have a higher density and higher nitrogen content, and consequently much lower reactivity than straight-run vacuum gas oils during fluid catalytic cracking (FCC). The conversion of H-Oil gas oils observed in a laboratory catalytic cracking unit at constant operating conditions showed a 20 wt.% lower conversion rate than straight-run hydrotreated vacuum gas oil. Thus, a revamp of commercial FCC units, and the selection of a higher activity catalyst with lower coke selectivity is needed to provide the stable trouble-free operation of the unit. The performed revamp of the commercial FCC unit allowed a stable operation at a higher throughput. It also allowed an increased riser outlet temperature from 532 to 550 °C; increased maximum allowable regenerator temperature from 705 to 730 °C; decreased afterburning from 12 to 6 °C; decreased NOx emissions in the flue gas from 250 to 160 mg/Nm3; improved catalyst regeneration; decreased catalyst losses to 0.0142 kg/t feed; and improved catalyst circulation at a higher throughput. It was confirmed in the commercial FCC unit that the H-Oil light vacuum gas oil is the least reactive H-Oil gas oil during catalytic cracking. Full article
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10 pages, 1303 KiB  
Article
Experimental Study on Interface Frictional Characteristics between Sand and Steel Pipe Jacking
by Zhe Mei, Anfeng Xiao, Jiahao Mei, Jinqiu Hu and Peng Zhang
Appl. Sci. 2023, 13(3), 2016; https://doi.org/10.3390/app13032016 - 3 Feb 2023
Cited by 3 | Viewed by 1424
Abstract
In order to study the variation law of shear frictional characteristics of the steel pipe jacking and sand interface under different working conditions, the shear stress–strain curve between five different particle sizes of sand and steel pipe jacking under different normal stress and [...] Read more.
In order to study the variation law of shear frictional characteristics of the steel pipe jacking and sand interface under different working conditions, the shear stress–strain curve between five different particle sizes of sand and steel pipe jacking under different normal stress and slurry lubrication conditions was measured by using a direct shear device, and the internal friction angle, friction coefficient and cohesion of the pipe–soil interface were calculated by regression analysis. The test results show that the shear stress between sand and steel pipe jacking decreases with the increase of the average particle size of the sand, and the strain-softening phenomenon occurs. The normal stress does not change the trend of the shear stress–strain curve at the pipe–soil interface, and the peak and residual values of the shear stress increase with the increase of the normal stress. The peak and residual values of the shear stress at the pipe–soil interface under the slurry lubrication condition are smaller than those under the no slurry lubrication condition. The peak shear stress between the pipe and soil under the lubricated slurry condition decreases by about 20%. The internal friction angle and friction coefficient of the pipe–soil interface decrease with the increase of the particle size, and there is no obvious pattern between the cohesion quantity relationship and the average particle size. Full article
(This article belongs to the Special Issue Advances in Tunneling and Underground Engineering)
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21 pages, 21098 KiB  
Article
Evaluation of Artifacts and Misinterpretation in 2D Electrical Resistivity Tomography Caused by Three-Dimensional Resistive Structures of Regular or Irregular Shapes
by Raffaele Martorana and Patrizia Capizzi
Appl. Sci. 2023, 13(3), 2015; https://doi.org/10.3390/app13032015 - 3 Feb 2023
Cited by 1 | Viewed by 2143
Abstract
Electrical resistivity tomography (ERT) is a well-known geophysical method applied to geological, hydrogeological and geoenvironmental research. To date, 2D ERT is still used much more than 3D ERT, thanks to its greater immediacy, survey speed and lower complexity in processing and inversion. However, [...] Read more.
Electrical resistivity tomography (ERT) is a well-known geophysical method applied to geological, hydrogeological and geoenvironmental research. To date, 2D ERT is still used much more than 3D ERT, thanks to its greater immediacy, survey speed and lower complexity in processing and inversion. However, the assumption of two-dimensionality of the underground structures can mean that the effects of 3D structures on the 2D ERT can sometimes lead to gross errors in interpretation. This work aims to evaluate these effects by testing synthetic and experimental models. Numerical simulations are performed starting from different resistivity models, and from the results, 2D data sets are derived to study and quantify the effects of 2D inversion on 3D structures. Tests simulating prismatic resistive blocks with a vertical square section are presented. Prisms extend orthogonally to the survey line. Depending on their length, they range from a minimum equal to the length of the section (cubic resistive block) to infinity (2D prism). On these models, 2D and 3D electrical resistivity tomography (ERT) surveys are simulated. The results show that resistive blocks with a limited extension orthogonal to the profile are not effectively resolved by 2D ERT. Additionally, resistivity values obtained from a 2D ERT inversion on a 3D resistive prism are underestimated more than those obtained on the corresponding 2D prism when compared with the true value. This underestimation increases with the three-dimensional characteristics. Furthermore, resistive blocks located near the survey line but not crossed by it create artifacts that can lead to erroneous interpretations. A field test performed on a calcarenite quarry, of which the three-dimensional geophysical model was reconstructed, confirmed the results obtained by the synthetic tests, highlighting that the effects of three-dimensionality can lead to the identification of artifacts in the vertical section or produce strong errors in the estimation of depth and size, thus causing misleading statements. Full article
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21 pages, 1106 KiB  
Article
An Integrated Quality Index of High-Rise Residential Buildings for All Lifecycle Stages of a Construction Facility
by Azariy Lapidus, Dmitriy Topchiy, Tatyana Kuzmina, Yana Shesterikova and Tembot Bidov
Appl. Sci. 2023, 13(3), 2014; https://doi.org/10.3390/app13032014 - 3 Feb 2023
Cited by 2 | Viewed by 1823
Abstract
The study focuses on developing a methodology for calculating an integrated quality index of administrative and engineering solutions that affect the safety of multi-storey residential buildings at each stage of their lifecycle. This method can be used to design a tool for assessing [...] Read more.
The study focuses on developing a methodology for calculating an integrated quality index of administrative and engineering solutions that affect the safety of multi-storey residential buildings at each stage of their lifecycle. This method can be used to design a tool for assessing the integrated quality of multi-storey residential buildings at each stage of production. Advanced quality assessment methods were analyzed within the framework of this study. The analysis led to the conclusion that the most relevant problem is the lack of an integrated approach to the quality assessment of multi-storey residential buildings. Having studied an extensive number of research works, the authors identified the main parameters that affect the quality of a construction facility. The aims of the study were to (1) develop an integrated quality index for multi-storey residential buildings (this index is to be applicable as early as at the stage of pre-construction arrangements); (2) develop methods for calculating and evaluating the integrated quality index for high-rise residential buildings at the stage of construction arrangements; (3) improve the efficiency of administrative and engineering solutions; and (4) devise a mathematical model that will identify the numerical value of the proposed multi-factor criteria. The research results show the feasibility and expediency of introducing this methodology in residential construction as it allows for a comprehensive measurement and quality assessment of high-rise residential buildings. Full article
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13 pages, 10980 KiB  
Article
Effect of Feed Rate on the Force and Energy in the Cutting Process Using Planar Technical Blades
by Tomasz Chaciński, Bartosz Zieliński and Krzysztof Nadolny
Appl. Sci. 2023, 13(3), 2013; https://doi.org/10.3390/app13032013 - 3 Feb 2023
Viewed by 1085
Abstract
Considering the technological processes taking place in fish processing enterprises (skinning), it is possible to specify various factors affecting the tool life and process efficiency. The paper presents the methodology of the study and the results and analysis of the collected data on [...] Read more.
Considering the technological processes taking place in fish processing enterprises (skinning), it is possible to specify various factors affecting the tool life and process efficiency. The paper presents the methodology of the study and the results and analysis of the collected data on the effect of the cutting speed of the technical blade used in the fish skinning process on the forces occurring in the cutting process. A special test stand was used in the study, which allowed obtaining repeatable results at a wide range of cutting speed values in the cutting process (70–400 mm/s). The study also determined the values of work W and power P, as well as the ej index (unit energy intensity index), which helped to select the most favorable blade feed rate parameter. The results indicated the most favorable cutting speed parameter and showed a clear relationship between the feed rate and the force and energy expenditure; as the cutting speed increases, an upward trend in force and energy expenditure was noted. Full article
(This article belongs to the Section Mechanical Engineering)
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12 pages, 2973 KiB  
Article
Diffraction of the Field of a Grounded Cable on an Elongated Dielectric Spheroid in a Conducting Layer
by Yuri Kuzmin and Stanislav Proshkin
Appl. Sci. 2023, 13(3), 2012; https://doi.org/10.3390/app13032012 - 3 Feb 2023
Viewed by 1022
Abstract
Based on a rigorous solution to the problem, analytical expressions are obtained for calculating the diffraction of the electromagnetic field of a grounded cable on an elongated dielectric spheroid in a conductive layer. The field of a grounded AC cable in a conductive [...] Read more.
Based on a rigorous solution to the problem, analytical expressions are obtained for calculating the diffraction of the electromagnetic field of a grounded cable on an elongated dielectric spheroid in a conductive layer. The field of a grounded AC cable in a conductive layer is determined by solving the Helmholtz equation for the vector potential by using the method of integral Fourier–Bessel transformations, taking into account the boundary conditions at the bottom and surface of the conductive layer. The process of finding the secondary field of an elongated dielectric spheroid on an alternating current in a conducting layer is divided into two stages. First, we find an exact solution to the problem of an elongated dielectric spheroid at a constant current in a homogeneous field, in free space, decomposing this solution into a Taylor series and retaining the first term, which is a dipole approximation. In the second stage, the resulting field as the sum of the fields of the horizontal and vertical dipoles is analytically continued into the frequency domain. The field of the horizontal and vertical dipoles in the conducting layer is obtained by using the method of integral Fourier–Bessel transformations, taking into account the boundary conditions at the bottom and surface of the conducting layer. The resulting solution is presented in a closed form in elementary functions and has an accuracy level acceptable for the practice. Graphs showing the flow characteristics of an elongated dielectric spheroid modeling a swimmer in a light diving suit are given. The influence of the water–air boundary on the increase in the secondary field of the dielectric spheroid, which leads to an increase in the reliability of object detection, is revealed. The practical implementation of the described device protected by a patent and the experimental data of testing the device layout on the Gulf of Finland are given. A good agreement between the theoretical and experimental flow characteristics of a dielectric object both in shape, amplitude, and phase, is revealed. Full article
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16 pages, 5469 KiB  
Article
Dynamic Load Test and Contact Force Analysis of the AERORail Structure
by Fangyuan Li, Zhenwei Guo, Yunxuan Cui and Peifeng Wu
Appl. Sci. 2023, 13(3), 2011; https://doi.org/10.3390/app13032011 - 3 Feb 2023
Cited by 3 | Viewed by 1682
Abstract
The flexible structure of the new type of aerial track studied in this paper is formed by strings and tracks, which have obvious dynamic characteristics under the action of vehicle moving loads and is also an important factor affecting its performance. The paper [...] Read more.
The flexible structure of the new type of aerial track studied in this paper is formed by strings and tracks, which have obvious dynamic characteristics under the action of vehicle moving loads and is also an important factor affecting its performance. The paper uses the full-scale model of AERORail, based on the modal test under a specific span, combined with the fundamental frequency analysis of the structure, and carries out the dynamic load test to determine the change law of the contact force acting on the rail by the dynamic load. The time-domain improved algorithm based on the method of moments is used to identify and analyze the dynamic loads under different spans and vehicle speeds and to determine the correlation between the dispatched loads and the spans and vehicle speeds. It is proven that the occurrence time and frequency of the contact force are related to the passing time of the vehicle. The contact force fluctuates with the change in the vehicle speed, but with the increase in the span, the fluctuation of the contact force decreases obviously. The relevant conclusions provide support for the layout of the AERORail vehicle load. For this innovative structure, the relevant conclusions provide the basis for the application of this novel structure. Full article
(This article belongs to the Special Issue Advances in Bridge Design and Structural Performance)
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20 pages, 732 KiB  
Article
Dynamic Computation Offloading with Deep Reinforcement Learning in Edge Network
by Yang Bai, Xiaocui Li, Xinfan Wu and Zhangbing Zhou
Appl. Sci. 2023, 13(3), 2010; https://doi.org/10.3390/app13032010 - 3 Feb 2023
Cited by 1 | Viewed by 1776
Abstract
With the booming proliferation of user requests in the Internet of Things (IoT) network, Edge Computing (EC) is emerging as a promising paradigm for the provision of flexible and reliable services. Considering the resource constraints of IoT devices, for some delay-aware user requests, [...] Read more.
With the booming proliferation of user requests in the Internet of Things (IoT) network, Edge Computing (EC) is emerging as a promising paradigm for the provision of flexible and reliable services. Considering the resource constraints of IoT devices, for some delay-aware user requests, a heavy-workload IoT device may not respond on time. EC has sparked a popular wave of offloading user requests to edge servers at the edge of the network. The orchestration of user-requested offloading schemes creates a remarkable challenge regarding the delay in user requests and the energy consumption of IoT devices in edge networks. To solve this challenge, we propose a dynamic computation offloading strategy consisting of the following: (i) we propose the concept of intermediate nodes, which can minimize the delay in user requests and the energy consumption of the current tasks handled by IoT devices by dynamically combining task-offloading and service migration strategies; (ii) based on the workload of the current network, the intermediate node selection problem is modeled as a multi-dimensional Markov Decision Process (MDP) space, and a deep reinforcement learning algorithm is implemented to reduce the large MDP space and make a fast decision. Experimental results show that this strategy is superior to the existing baseline methods to reduce delays in user requests and the energy consumption of IoT devices. Full article
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11 pages, 1859 KiB  
Article
Cleaning Phenolic Compounds Present in Water Using Salting-Out Effect with DCA-Based Ionic Liquids
by Olalla G. Sas, Ángeles Domínguez and Begoña González
Appl. Sci. 2023, 13(3), 2009; https://doi.org/10.3390/app13032009 - 3 Feb 2023
Cited by 1 | Viewed by 1593
Abstract
Water is an essential natural resource, and its contamination is an important issue at present. This study aimed to increase the techniques that can be used to clean and reuse industrial wastewater by studying the feasibility of an aqueous two-phase system to eliminate [...] Read more.
Water is an essential natural resource, and its contamination is an important issue at present. This study aimed to increase the techniques that can be used to clean and reuse industrial wastewater by studying the feasibility of an aqueous two-phase system to eliminate phenolic compounds from aqueous systems. The system was prepared using two hydrophilic ionic liquids based on dicyanamide anion, 1-ethyl-3-methylimidazlium dicyanamide [EMim] [DCA], and 1-butyl-3-methylimidazolium dicyanamide [BMim][DCA], and one inorganic salt, K3PO4, at three different concentrations (20, 30, and 40%). The process was tested for the removal of phenol, o-cresol, 2-chlorophenol, and a mixture of them (PCM) at initial concentrations from 0.003 to 15 g·L−1 in water. The extraction efficiencies for all the studied systems were calculated. The influence of the structure of the cation, the concentration of salt, and the initial concentration of the extracted compounds in the extraction yields were recorded. In general, the obtained results were high for all the studied systems, with extraction efficiencies of more than 90% representing the highest removal of the 2-chlorophenol compound using [EMim] [DCA] at the highest concentration of salt. Full article
(This article belongs to the Special Issue Perspectives in Water Recycling)
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21 pages, 1373 KiB  
Article
Cramér–Rao Lower Bounds on 3D Position and Orientation Estimation in Distributed Ranging Systems
by Sharanya Srinivas, Samuel Welker, Andrew Herschfelt and Daniel W. Bliss
Appl. Sci. 2023, 13(3), 2008; https://doi.org/10.3390/app13032008 - 3 Feb 2023
Viewed by 2200
Abstract
As radio frequency (RF) hardware continues to improve, many technologies that were traditionally impractical have suddenly become viable alternatives to legacy systems. Two-way ranging (TWR) is often considered a poor positioning solution for airborne and other vehicular navigation systems due to its low [...] Read more.
As radio frequency (RF) hardware continues to improve, many technologies that were traditionally impractical have suddenly become viable alternatives to legacy systems. Two-way ranging (TWR) is often considered a poor positioning solution for airborne and other vehicular navigation systems due to its low precision, poor angular resolution, and precise timing requirements. With the advent of modern RF hardware and advanced processing techniques, however, modern studies have experimentally demonstrated TWR systems with an unprecedented, sub-centimeter ranging precision with low size, weight, power, and cost (SWaP-C) consumer-grade hardware. This technique enables a new class of positioning, navigation, and timing (PNT) capabilities for urban and commercial aircraft but also instigates new system design challenges such as antenna placement, installation of new electronics, and design of supporting infrastructure. To inform these aircraft design decisions, we derive 2D and 3D Cramér–Rao lower bounds (CRLBs) on position and orientation estimation in a multi-antenna TWR system. We specifically formulate these bounds as a function of the number of antennas, platform geometry, and geometric dilution of precision (GDoP) to inform aircraft design decisions under different mission requirements. We simulate the performance of several classic position and orientation estimators in this context to validate these bounds and to graphically depict the expected performance with respect to these design considerations. To improve the accessibility of these highly theoretical results, we also present a simplified discussion of how these bounds may be applied to common airborne applications and suggest best practices for using them to inform aircraft design decisions. Full article
(This article belongs to the Special Issue Aerospace Vehicle Design under Uncertainties)
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24 pages, 3860 KiB  
Review
On the Use of Deep Learning for Video Classification
by Atiq ur Rehman, Samir Brahim Belhaouari, Md Alamgir Kabir and Adnan Khan
Appl. Sci. 2023, 13(3), 2007; https://doi.org/10.3390/app13032007 - 3 Feb 2023
Cited by 12 | Viewed by 5645
Abstract
The video classification task has gained significant success in the recent years. Specifically, the topic has gained more attention after the emergence of deep learning models as a successful tool for automatically classifying videos. In recognition of the importance of the video classification [...] Read more.
The video classification task has gained significant success in the recent years. Specifically, the topic has gained more attention after the emergence of deep learning models as a successful tool for automatically classifying videos. In recognition of the importance of the video classification task and to summarize the success of deep learning models for this task, this paper presents a very comprehensive and concise review on the topic. There are several existing reviews and survey papers related to video classification in the scientific literature. However, the existing review papers do not include the recent state-of-art works, and they also have some limitations. To provide an updated and concise review, this paper highlights the key findings based on the existing deep learning models. The key findings are also discussed in a way to provide future research directions. This review mainly focuses on the type of network architecture used, the evaluation criteria to measure the success, and the datasets used. To make the review self-contained, the emergence of deep learning methods towards automatic video classification and the state-of-art deep learning methods are well explained and summarized. Moreover, a clear insight of the newly developed deep learning architectures and the traditional approaches is provided. The critical challenges based on the benchmarks are highlighted for evaluating the technical progress of these methods. The paper also summarizes the benchmark datasets and the performance evaluation matrices for video classification. Based on the compact, complete, and concise review, the paper proposes new research directions to solve the challenging video classification problem. Full article
(This article belongs to the Special Issue Digital Image Processing: Advanced Technologies and Applications)
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20 pages, 3760 KiB  
Article
Performance Comparison of Machine Learning Disruption Predictors at JET
by Enrico Aymerich, Barbara Cannas, Fabio Pisano, Giuliana Sias, Carlo Sozzi, Chris Stuart, Pedro Carvalho, Alessandra Fanni and the JET Contributors
Appl. Sci. 2023, 13(3), 2006; https://doi.org/10.3390/app13032006 - 3 Feb 2023
Cited by 7 | Viewed by 1933
Abstract
Reliable disruption prediction (DP) and disruption mitigation systems are considered unavoidable during international thermonuclear experimental reactor (ITER) operations and in the view of the next fusion reactors such as the DEMOnstration Power Plant (DEMO) and China Fusion Engineering Test Reactor (CFETR). In the [...] Read more.
Reliable disruption prediction (DP) and disruption mitigation systems are considered unavoidable during international thermonuclear experimental reactor (ITER) operations and in the view of the next fusion reactors such as the DEMOnstration Power Plant (DEMO) and China Fusion Engineering Test Reactor (CFETR). In the last two decades, a great number of DP systems have been developed using data-driven methods. The performance of the DP models has been improved over the years both for a more appropriate choice of diagnostics and input features and for the availability of increasingly powerful data-driven modelling techniques. However, a direct comparison among the proposals has not yet been conducted. Such a comparison is mandatory, at least for the same device, to learn lessons from all these efforts and finally choose the best set of diagnostic signals and the best modelling approach. A first effort towards this goal is made in this paper, where different DP models will be compared using the same performance indices and the same device. In particular, the performance of a conventional Multilayer Perceptron Neural Network (MLP-NN) model is compared with those of two more sophisticated models, based on Generative Topographic Mapping (GTM) and Convolutional Neural Networks (CNN), on the same real time diagnostic signals from several experiments at the JET tokamak. The most common performance indices have been used to compare the different DP models and the results are deeply discussed. The comparison confirms the soundness of all the investigated machine learning approaches and the chosen diagnostics, enables us to highlight the pros and cons of each model, and helps to consciously choose the approach that best matches with the plasma protection needs. Full article
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20 pages, 467 KiB  
Article
Improving Classification Performance with Statistically Weighted Dimensions and Dimensionality Reduction
by Uraiwan Buatoom and Muhammad Usman Jamil
Appl. Sci. 2023, 13(3), 2005; https://doi.org/10.3390/app13032005 - 3 Feb 2023
Cited by 4 | Viewed by 1942
Abstract
In image classification, various techniques have been developed to enhance the performance of principal component analysis (PCA) dimension reduction techniques with guiding weighting features to remove redundant and irrelevant features. This study proposes the statistically weighted dimension technique based on three distribution-related class [...] Read more.
In image classification, various techniques have been developed to enhance the performance of principal component analysis (PCA) dimension reduction techniques with guiding weighting features to remove redundant and irrelevant features. This study proposes the statistically weighted dimension technique based on three distribution-related class behaviors; collection-class, inter-class, and intra-class to enhance the feature-extraction ability before using PCA for feature selection. The data from the statistics-weighted dimension spaces is utilized to reduce dimensionality by reducing the large index data into smaller index data using PCA. The new principal component from the weighted training part by an unlabeled dataset is constructed and then the image is classified efficiently. Additionally, the weighting direction investigates the pros and cons of promoting and demoting to determine the worst or best option utilizing the exponents of three proposed weighted scheme. The experiment is conducted using three datasets, MNIST, E-MNIST, and F-MNIST, along with three image classification algorithms, logistic Regression, KNN, and SVM (RBF). The results clearly demonstrate that the statistically weighted dimension feature can improve the conventional classification accuracy in lower dimensions with an appropriate combination of weighting nearly 3% for the best solution on dimensionality reduction by more than 50%. Full article
(This article belongs to the Section Computing and Artificial Intelligence)
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19 pages, 8075 KiB  
Article
Quantitative Calculation of the Most Efficient LED Light Combinations at Specific Growth Stages for Basil Indoor Horticulture: Modeling through Design of Experiments
by Silvia Barbi, Francesco Barbieri, Claudia Taurino, Alessandro Bertacchini and Monia Montorsi
Appl. Sci. 2023, 13(3), 2004; https://doi.org/10.3390/app13032004 - 3 Feb 2023
Cited by 1 | Viewed by 2004
Abstract
Indoor farms are a promising way to obtain vegetables in standard quantity and quality. As opposed to previous studies, this study attempts to calculate optimized LED light conditions for different growth stages (five-days time step) of basil (Ocimum basilicum) to enhance [...] Read more.
Indoor farms are a promising way to obtain vegetables in standard quantity and quality. As opposed to previous studies, this study attempts to calculate optimized LED light conditions for different growth stages (five-days time step) of basil (Ocimum basilicum) to enhance its indoor growth through a statistical approach. Design of Experiments (DoE) was used to plan a limited number of experiments (20) and to calculate quantitatively the effect of different light recipes on four responses: the number of plants, their height, the Leaf Area Index, and the amount of water used. Different proportions (from 25% to 77%) of Hyper Red (660 nm) and Deep Blue (451 nm), intensities in terms of LEDs–plant distance (60, 70 and 80 cm), and the addition of Warm White (3000 K) LEDs were considered as independent variables. The obtained models suggest that a light recipe tailored for every growth step in the plant’s life is beneficial. Appropriate LEDs must be carefully chosen at the beginning of growth, whereas distance becomes relevant at the end. This is confirmed by the results analysis carried out at the end of an additional growth test where the optimal light recipe extracted from the DoE’s results were used. Full article
(This article belongs to the Section Agricultural Science and Technology)
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22 pages, 3501 KiB  
Review
Evaluation and Current State of Primary and Secondary Zinc Production—A Review
by Henryk Kania and Mariola Saternus
Appl. Sci. 2023, 13(3), 2003; https://doi.org/10.3390/app13032003 - 3 Feb 2023
Cited by 22 | Viewed by 5947
Abstract
This article presents the history of zinc, its production and demand. The quantity of zinc production, both primary zinc from ores and concentrates, and secondary zinc from scrap and zinc-rich waste, was discussed. A comprehensive economic analysis covers zinc prices in the years [...] Read more.
This article presents the history of zinc, its production and demand. The quantity of zinc production, both primary zinc from ores and concentrates, and secondary zinc from scrap and zinc-rich waste, was discussed. A comprehensive economic analysis covers zinc prices in the years 1960–2021. The basic methods of obtaining zinc from ores, including pyrometallurgical (Imperial Smelting Process ISP, Kivcet, Ausmelt) and hydrometallurgical (roasting–leaching–electrowinning RLE, atmospheric direct leaching ADL, Engitec Zinc Extraction EZINEX, zinc pressure leach) and their short characteristics, are presented. The global zinc market and the main areas of its application were analyzed. Technologies used for the recovery of zinc from scrap are discussed along with their characteristics. Galvanized steel is the main source of secondary zinc, both in the galvanizing process and in the remelting of galvanized steel. It can be easily recycled with other scrap steel in the electric arc furnace (EAF) for steel production. Currently, with high volatility in the price of zinc, as well as its natural resources in the earth’s crust, recycling is an important activity, despite the fact that zinc concentrates have a relatively constant chemical composition, while the resulting zinc waste contains zinc in varying amounts. Full article
(This article belongs to the Special Issue Selected Papers in the Section Materials 2022)
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16 pages, 8818 KiB  
Article
A Circularly Polarized mmWave Dielectric-Resonator-Antenna Array for Off-Body Communications
by Tarek S. Abdou, Rola Saad and Salam K. Khamas
Appl. Sci. 2023, 13(3), 2002; https://doi.org/10.3390/app13032002 - 3 Feb 2023
Cited by 4 | Viewed by 1910
Abstract
This paper presents a novel 28 GHz circularly polarized rectangular dielectric-resonator antenna (DRA) array for millimeter-wave (mmWave) off-body applications. A feed network incorporating cross slots was utilized in the rectangular DRA design to realize circular polarization (CP). In terms of the free-space wavelength, [...] Read more.
This paper presents a novel 28 GHz circularly polarized rectangular dielectric-resonator antenna (DRA) array for millimeter-wave (mmWave) off-body applications. A feed network incorporating cross slots was utilized in the rectangular DRA design to realize circular polarization (CP). In terms of the free-space wavelength, λo, the DRA dimensions were (0.48λo × 0.48λo × 0.27λo) at 28 GHz. The antenna array was simulated by incorporating dielectric layers with parameters that are equivalent to those of the human body at the desired frequency of 28 GHz for off-body communications. Moreover, the precise alignment and assembly of the DRA, which pose major difficulties at mmWave frequencies, were achieved by outlining the DRA positions on the ground plane using a three-dimensional (3D) printer. The array configuration was fabricated and measured with excellent performance, realizing a measured impedance bandwidth of 29% in conjunction with an axial-ration (AR) bandwidth of 13% and a broadside gain of 13.7 dBic at 28 GHz. Full article
(This article belongs to the Special Issue Antenna Analysis and Design)
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18 pages, 2534 KiB  
Article
Is the Slag Heap of a Former Ferrochromium Plant a Significant Environmental Hazard?
by Magdalena Wróbel, Angelika Pieśniewska, Farhad Zeynalli, Kacper Kapelko, Beata Hanus-Lorenz and Justyna Rybak
Appl. Sci. 2023, 13(3), 2001; https://doi.org/10.3390/app13032001 - 3 Feb 2023
Viewed by 1356
Abstract
This study assessed the possible impact of a former ferrochromium plant in Siechnice (Lower Silesia, Poland) on water reservoirs and living organisms. The metal concentrations (Zn, Cu, Pb, Fe, and Cr) in the sediments were determined, along with ecotoxicological studies that were conducted [...] Read more.
This study assessed the possible impact of a former ferrochromium plant in Siechnice (Lower Silesia, Poland) on water reservoirs and living organisms. The metal concentrations (Zn, Cu, Pb, Fe, and Cr) in the sediments were determined, along with ecotoxicological studies that were conducted on both the sediments and the surface water of three water bodies that border the slag heap. The samples of the sediments and water were taken at different distances from the landfill area. The studies also covered a human health risk assessment. The highest concentrations of all the studied elements were observed in the sediments taken from the water reservoir closest to the landfill. In the case of the sediments, a 30% death rate for Heterocypris incongruens (Ostracodtoxkit F) was recorded at the same site. Additionally, at this site, the ecotoxicological studies on the surface water revealed the highest mortality for Daphnia magna (Daphtoxkit F magna) and the lowest values of LC50 for algae (Algaltoxkit). The health risk assessment of the sediments was estimated by calculating the noncarcinogenic health risk using the hazard quotient (HQ) and hazard index (HI), and the carcinogenic risk was calculated using the excessive risk of cancer development (ECR) measurement. The hazard index (HIing) for Cr exceeded 1 for children, which suggests that possible adverse health effects might occur for humans. The ECR values calculated for Cr and Pb were above the range limit of 106. The value for Cr was the highest for the sediments from the closest water reservoir to the landfill for both children and adults. Studies prove that the water reservoirs located near landfills pose potential ecological risks, and the risk is the highest where the distance is the shortest from the slag heap. In prospective human health risk assessments, the sediments from the closest water body pose a potential carcinogenic health risk to humans, especially to fish consumers, i.e., the residents of neighboring areas who might experience severe health problems from the intake of Cr and Pb through fish consumption. Significant steps should be taken to reduce Cr concentrations in the sediments to minimize the risk of human health adverse effects. Full article
(This article belongs to the Special Issue Aquatic Toxicology and Aquaculture: Questions and Advances)
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38 pages, 32558 KiB  
Article
Possibilities for the Flow of Water and Blood through a Graphene Layer in a Geometry Analogous to Human Arterioles: An Observational Study
by S. Shankar Narayan, Abdulkafi M. Saeed, Nahid Fatima, Fuad S. Al-Duais, Khalid Abdulkhaliq M. Alharbi, Venkatesh Puneeth, M. R. Gorji, Nidhal Ben Kheder and Shaimaa A. M. Abdelmohsen
Appl. Sci. 2023, 13(3), 2000; https://doi.org/10.3390/app13032000 - 3 Feb 2023
Cited by 3 | Viewed by 1889
Abstract
Atherosclerosis and aneurysm are two non-communicable diseases that affect the human arterial network. The arterioles undergo dimensional changes that prominently influence the flow of oxygen and nutrients to distal organs and organ systems. Several studies have emerged discussing the various possibilities for the [...] Read more.
Atherosclerosis and aneurysm are two non-communicable diseases that affect the human arterial network. The arterioles undergo dimensional changes that prominently influence the flow of oxygen and nutrients to distal organs and organ systems. Several studies have emerged discussing the various possibilities for the circumstances surrounding the existence of these pathologies. In the present work, we analyze the flow of blood across the stenosis and the aneurysmic sac in contrast with the flow of water to explore alterations in the flow characteristics caused by introduction of the graphene layer. We investigate the blood flow past the graphene layer with varying porosity. The study is undertaken to replace usage of a stent along a blocked artery by inserting a thin layer of graphene along the flow channel in the post-pathological section of the geometry. To explain the flow, a 2D mathematical model is constructed, and the validity and exclusivity of the model’s solution are examined. When the artery wall is assumed to be inelastic, the computation of the mathematical system is evaluated using a finite element method (FEM) solver. We define a new parameter called critical porosity Cεp to explore the flow possibilities through the graphene layer. The findings indicate that the flow pattern was adversely affected by the graphene layer that was added to the flow field. The negative impact on the flow could be due to the position of the graphene layer placed. The Cεp values for the flow of blood across healthy arteriole, stenosed arteriole, and aneurysmic arteriole segments were 5.7%, 3.5%, and 3.5% respectively. The critical porosity values were achieved with precision in terms of linear errors 8.1×1012, 7.7×1012, and 3.9×1012, respectively. The consequences of the present study disclose various possible ways to utilize graphene and its compounds in the medical and clinical arena, with a prior exploration of the chemical properties of the compound. The idea and the methodology applied for the present study are novel as there have been no previous research works available in this direction of the research field. Full article
(This article belongs to the Section Fluid Science and Technology)
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17 pages, 4070 KiB  
Article
STrans-YOLOX: Fusing Swin Transformer and YOLOX for Automatic Pavement Crack Detection
by Hui Luo, Jiamin Li, Lianming Cai and Mingquan Wu
Appl. Sci. 2023, 13(3), 1999; https://doi.org/10.3390/app13031999 - 3 Feb 2023
Cited by 7 | Viewed by 2251
Abstract
Automatic pavement crack detection is crucial for reducing road maintenance costs and ensuring transportation safety. Although convolutional neural networks (CNNs) have been widely used in automatic pavement crack detection, they cannot adequately model the long-range dependencies between pixels and easily lose edge detail [...] Read more.
Automatic pavement crack detection is crucial for reducing road maintenance costs and ensuring transportation safety. Although convolutional neural networks (CNNs) have been widely used in automatic pavement crack detection, they cannot adequately model the long-range dependencies between pixels and easily lose edge detail information in complex scenes. Moreover, irregular crack shapes also make the detection task challenging. To address these issues, an automatic pavement crack detection architecture named STrans-YOLOX is proposed. Specifically, the architecture first exploits the CNN backbone to extract feature information, preserving the local modeling ability of the CNN. Then, Swin Transformer is introduced to enhance the long-range dependencies through a self-attention mechanism by supplying each pixel with global features. A new global attention guidance module (GAGM) is used to ensure effective information propagation in the feature pyramid network (FPN) by using high-level semantic information to guide the low-level spatial information, thereby enhancing the multi-class and multi-scale features of cracks. During the post-processing stage, we utilize α-IoU-NMS to achieve the accurate suppression of the detection boxes in the case of occlusion and overlapping objects by introducing an adjustable power parameter. The experiments demonstrate that the proposed STrans-YOLOX achieves 63.37% mAP and surpasses the state-of-the-art models on the challenging pavement crack dataset. Full article
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30 pages, 7722 KiB  
Article
Investigation on the Association of Differential Evolution and Constructal Design for Geometric Optimization of Double Y-Shaped Cooling Cavities Inserted into Walls with Heat Generation
by Gill Velleda Gonzales, Cesare Biserni, Emanuel da Silva Diaz Estrada, Gustavo Mendes Platt, Liércio André Isoldi, Luiz Alberto Oliveira Rocha, Antônio José da Silva Neto and Elizaldo Domingues dos Santos
Appl. Sci. 2023, 13(3), 1998; https://doi.org/10.3390/app13031998 - 3 Feb 2023
Cited by 2 | Viewed by 1454
Abstract
In the constructal design method, the comprehension of the effect of design on the system performance is crucial to understanding the contributions of the degrees of freedom or constraints in the system evolution in direction of optimal configurations. However, problems with many degrees [...] Read more.
In the constructal design method, the comprehension of the effect of design on the system performance is crucial to understanding the contributions of the degrees of freedom or constraints in the system evolution in direction of optimal configurations. However, problems with many degrees of freedom are prohibitive of optimization with exhaustive search, requiring meta-heuristic strategies. Therefore, the investigation of the optimization algorithms is essential. This work investigates the canonical differential evolution algorithm associated with the constructal design for the geometric optimization of an isothermal double Y-shaped cooling cavity inserted into a wall with internal heat generation. The effect of four degrees of freedom over the thermal performance of the system is investigated using sixteen different combinations of differential evolution algorithms: four variations of mutation parameter, two values of amplification factor (F) and two values of crossover rate (CR). The non-parametric statistical methods of Kruskal–Wallis and Dunn test were used to identify the parameters that improve the meta-heuristic efficiency. Results indicated that the proposed methodology selected the proper combination of DE algorithm parameters (CR, F, and mutation) that led to the best effect of degrees of freedom over the thermal performance in all optimization levels investigated. Full article
(This article belongs to the Special Issue New Perspectives in Computational Thermal Fluid Dynamics Studies)
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10 pages, 2872 KiB  
Article
Research on Defect Inspection Technology for Bump Height in Wafer-Level Packaging Based on the Triangulation Method
by Fanchang Meng, Zili Zhang, Yanhui Kang, Chengjun Cui, Dezhao Wang, Xinxin Zhang and Weihu Zhou
Appl. Sci. 2023, 13(3), 1997; https://doi.org/10.3390/app13031997 - 3 Feb 2023
Cited by 1 | Viewed by 1927
Abstract
With the advent of the era of big data and the vigorous development of consumer electronics, the demand for higher-speed processing capacity for gigantic amounts of data is increasing; this requires finer and far more numerous connections between dies as an essential component [...] Read more.
With the advent of the era of big data and the vigorous development of consumer electronics, the demand for higher-speed processing capacity for gigantic amounts of data is increasing; this requires finer and far more numerous connections between dies as an essential component for connection and electronic communication between layers. The coplanarity of the height of micro bumps is crucial to ensure the reliability of the chip. The triangulation method has been widely used in various types of visual inspection applications over the past several years due to its high measurement accuracy and fast detection speed. In this paper, the application of triangulation technology is analyzed and used in micro bump height measurement. The measurement system proposed consists of a delicate design, a linearly arranged light projection module and a high-quality imaging module. Along the light stripe, multiple-height data of micro bumps are collected in a frame, and the full-field measurement is realized as the wafer is driven by the high-precision motional stage, following the optimal measurement route planned previously. In the scanning process, the images of the light strip projected on the top and bottom of the micro bumps are simultaneously acquired by the sophisticated micro vision system, and then the heights of micro bumps are calculated from a simple formula based on the geometry of the specimen and the system configuration. The experimental results demonstrate that the measuring deviation of the micro bump height has an accuracy of 1.5 μm. Full article
(This article belongs to the Section Applied Physics General)
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19 pages, 1808 KiB  
Review
A Review on the Potential Food Application of Lima Beans (Phaseolus lunatus L.), an Underutilized Crop
by Janet Adeyinka Adebo
Appl. Sci. 2023, 13(3), 1996; https://doi.org/10.3390/app13031996 - 3 Feb 2023
Cited by 7 | Viewed by 6919
Abstract
The world is facing the global challenges of insecurity, poverty and climate change, which can impede food availability, production and nutritional security. Due to these factors, the production and availability of crop species such as legumes, pulses and cereals are declining, while some [...] Read more.
The world is facing the global challenges of insecurity, poverty and climate change, which can impede food availability, production and nutritional security. Due to these factors, the production and availability of crop species such as legumes, pulses and cereals are declining, while some are gradually becoming extinct, which affects consumption. To meet global food demands, efforts should be geared towards promoting the cultivation and utilization of underexploited and neglected crops, which have the potential to improve food and nutrition security. However, the exploitation and utilization of crops mostly depend on existing knowledge. Therefore, this review gives an overview of the current knowledge regarding lima beans (Phaseolus lunatus L.), an underutilized legume that can serve as a promising potential food crop. While there are some studies on lima beans, they cannot compare to the abundance of studies on other legumes. It is essential to exploit the nutritional and health properties of this crop, as well as to explore processing techniques such as cooking, soaking, fermentation and germination for transforming them into other food forms. Despite the dearth of information on this crop compared to other legumes, there is a case for the promotion of lima beans, especially where there are incessant food shortages, as they will allow for dietary diversity. This is vital considering the vulnerability of world food systems, coupled with an ever-growing population, necessitating a focus on other neglected crops to improve food security. Full article
(This article belongs to the Section Food Science and Technology)
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