The 2023 MDPI Annual Report has
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28 pages, 965 KiB  
Article
Integrated Decision-Making of Urban Agriculture within the Greyfield Regeneration Environments (UAGR)
by Wenli Dong and Gangjian Lin
Buildings 2024, 14(5), 1415; https://doi.org/10.3390/buildings14051415 (registering DOI) - 14 May 2024
Abstract
Various urban environmental and social challenges have emerged during the rapid urban development. Urban agriculture has emerged as one of the practical solutions to address these urban issues and climate change. This study aims to establish a decision model for urban agriculture regeneration [...] Read more.
Various urban environmental and social challenges have emerged during the rapid urban development. Urban agriculture has emerged as one of the practical solutions to address these urban issues and climate change. This study aims to establish a decision model for urban agriculture regeneration that can be applied to improve the implementation of related projects. The study first reviews existing research on Urban Agriculture within the Greyfield Regeneration Environments (UAGR) and outlines the processes involved, including project initiation, construction, and operation management. It identifies 25 factors influencing UAGR and employs the Fuzzy Delphi method (FDM) to prioritize them based on expert judgments. Subsequently, the interpretative structural model (ISM) analysis method is applied to analyze the interrelationships among the 11 most important factors. Matrix operations and MATLAB programming are utilized to establish the influence relationship model based on expert questionnaires to determine the influence between each pair of factors. This results in a hierarchically structured decision model for UAGR. Finally, the decision-making model is applied to analyze the case study in Shanghai and Hangzhou. As urban agricultural activities are proliferating in rapid urbanization, the establishment of a decision-making model for UAGR can offer practical guidance to practitioners, facilitating the development of urban agriculture and mitigating climate change. Full article
(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)
17 pages, 7036 KiB  
Article
Adsorption of Chromium (III) and Chromium (VI) Ions from Aqueous Solution Using Chitosan–Clay Composite Materials
by Enkhtuya Majigsuren, Ulziidelger Byambasuren, Munkhpurev Bat-Amgalan, Enkhtuul Mendsaikhan, Naoki Kano, Hee Joon Kim and Ganchimeg Yunden
Polymers 2024, 16(10), 1399; https://doi.org/10.3390/polym16101399 (registering DOI) - 14 May 2024
Abstract
In this work, biopolymer chitosan and natural clay were used to obtain composite materials. The overall aim of this study was to improve the properties (porosity, thermal stability and density) of pure chitosan beads by the addition of clay and to obtain a [...] Read more.
In this work, biopolymer chitosan and natural clay were used to obtain composite materials. The overall aim of this study was to improve the properties (porosity, thermal stability and density) of pure chitosan beads by the addition of clay and to obtain a chitosan-based composite material for the adsorption of heavy metals from an aqueous solution, using Mongolian resources, and to study the adsorption mechanism. The natural clay was pre-treated with acid and heat to remove the impurities. The chitosan and pre-treated clay were mixed in different ratios (8:1, 8:2 and 8:3) for chemical processing to obtain a composite bead for the adsorption of chromium ions. The adsorption of Cr(III) and Cr(VI) was studied as a function of the solution pH, time, temperature, initial concentration of the chromium solution and mass of the composite bead. It was found that the composite bead obtained from the mixture of chitosan and treated clay with a mass ratio of 8:1 and 8:2 had the highest adsorption capacity (23.5 and 17.31 mg·g−1) for Cr(III) and Cr(VI), respectively, in the optimum conditions. The properties of the composite materials, prepared by mixing chitosan and clay with a ratio of 8:1 and 8:2, were investigated using XRD, SEM–EDS, BET and TG analysis. The adsorption mechanism was discussed based on the XPS analysis results. It was confirmed that the chromium ions were adsorbed in their original form, such as Cr(III) and Cr(VI), without undergoing oxidation or reduction reactions. Furthermore, Cr(III) and Cr(VI) were associated with the hydroxyl and amino groups of the composite beads during adsorption. The kinetic, thermodynamic and isothermal analysis of the adsorption process revealed that the interaction between the chitosan/clay composite bead and Cr(III) and Cr(VI) ions can be considered as a second-order endothermic reaction, as such the adsorption can be assessed using the Langmuir isotherm model. It was concluded that the composite bead could be used as an adsorbent for the removal of chromium ions. Full article
(This article belongs to the Special Issue Functional Polymers for Water and Wastewater Treatment)
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22 pages, 1968 KiB  
Article
Research on and Application of Feature Recognition and Intelligent Retrieval Method for Multi-Component Alloy Powder Injection Molding Gear Based on Partition Templates
by Yan Kong, Xiaoyi Cui, Zhibing Zhang and Yuqi Liu
Metals 2024, 14(5), 579; https://doi.org/10.3390/met14050579 (registering DOI) - 14 May 2024
Abstract
The forming process of multi-alloy gears by metal powder injection molding is tedious, and the current design process mainly depends on the experience of designers, which seriously affects the product development cycle and forming quality. In order to solve the problem of the [...] Read more.
The forming process of multi-alloy gears by metal powder injection molding is tedious, and the current design process mainly depends on the experience of designers, which seriously affects the product development cycle and forming quality. In order to solve the problem of the gear feature expression being missing, which hinders the automatic retrieval of similar parts in the analogical design process, a feature recognition and intelligent retrieval method for a multi-alloy powder injection molding gear based on partition templates is proposed in this paper. The partition templates of the gear are defined, and gear digitization is completed by using the automatic recognition algorithm. Searching for similar gear parts in the knowledge base, designers can analogically design the forming process for new parts according to the mature process of the parts in the knowledge base. The automatic identification and intelligent retrieval system developed according to this method has been implemented in two MIM (metal injection molding) product manufacturing enterprises. Case studies and industrial applications have proved the effectiveness of the system, the efficiency of identification and retrieval has been improved by more than 97%, and the number of mold tests has been reduced by 60%. Full article
(This article belongs to the Special Issue Structural and Functional Performances of Multi-Component Alloys)
15 pages, 753 KiB  
Article
Gastrointestinal Parasites in Owned Dogs in Serbia: Prevalence and Risk Factors
by Nemanja M. Jovanovic, Olga Bisenic, Katarina Nenadovic, Danica Bogunovic, Milan Rajkovic, Milan Maletic, Milorad Mirilovic and Tamara Ilic
Animals 2024, 14(10), 1463; https://doi.org/10.3390/ani14101463 (registering DOI) - 14 May 2024
Abstract
Dogs are the most popular pets worldwide. Close contact between dogs and people increases the risk of transmission of various zoonotic parasitic infections. Given the importance of veterinary medicine in preserving the One Health concept, the aim of this research was to identify [...] Read more.
Dogs are the most popular pets worldwide. Close contact between dogs and people increases the risk of transmission of various zoonotic parasitic infections. Given the importance of veterinary medicine in preserving the One Health concept, the aim of this research was to identify intestinal parasites that may have zoonotic potential and to evaluate risk factors (individual and environmental). The research was conducted in Serbia in 2022 and 2023 on 382 owned dogs, using qualitative methods of coprological examination with a concentration on parasitic elements. The overall prevalence of intestinal parasites was 62.6%, with the following detected: protozoa: Cystoisospora spp. (9.2%), Sarcocystis spp. (4.5%), Neospora caninum/Hammondia spp. (3.7%), Giardia intestinalis (11.8%); nematoda: Toxocara canis (11.5%), Toxascaris leonina (4.2%), family Ancylostomatidae (38.0%), Trichuris vulpis (21.5%), Capillaria spp. (10.5%); trematoda: Alaria alata (1.6%) and cestodes from the Taeniidae family (1.3%). Factors like age, size and coat length, as well as the way of living, attitude and diet were linked to a significantly higher (p < 0.05) prevalence of intestinal parasites. Based on the results of coprological diagnostics, this research indicates the importance of educating dog owners, conducting routine parasitological tests on their pets and regular deworming strategies. Full article
(This article belongs to the Special Issue Parasites and Parasitic Diseases in Small Animals)
21 pages, 39666 KiB  
Article
The Influence of the Addition of Basalt Powder on the Properties of Foamed Geopolymers
by Michał Łach, Barbara Kozub, Sebastian Bednarz, Agnieszka Bąk, Mykola Melnychuk and Adam Masłoń
Materials 2024, 17(10), 2336; https://doi.org/10.3390/ma17102336 (registering DOI) - 14 May 2024
Abstract
Geopolymers are binder materials that are produced by a chemical reaction between silica or aluminum compounds with an alkaline activating solution. Foamed geopolymer materials are increasingly being cited as a viable alternative to popular organic insulation materials. Since the foaming process of geopolymers [...] Read more.
Geopolymers are binder materials that are produced by a chemical reaction between silica or aluminum compounds with an alkaline activating solution. Foamed geopolymer materials are increasingly being cited as a viable alternative to popular organic insulation materials. Since the foaming process of geopolymers is difficult to control, and any achievements in improving the performance of such materials are extremely beneficial, this paper presents the effect of the addition of basalt powder on the properties of foamed geopolymers. This paper presents the results of physicochemical studies of fly ash and basalt, as well as mechanical properties, thermal properties, and structure analysis of the finished foams. The scope of the tests included density tests, compressive strength tests, tests of the thermal conductivity coefficient using a plating apparatus, as well as microstructure tests through observations using light and scanning microscopy. Ground basalt was introduced in amounts ranging from 0 to 20% by mass. It was observed that the addition of basalt powder contributes to a reduction in and spheroidization of pores, which directly affect the density and pore morphology of the materials tested. The highest density of 357.3 kg/m3 was characterized by samples with a 5 wt.% basalt powder addition. Their density was 14% higher than the reference sample without basalt powder addition. Samples with 20 wt.% basalt addition had the lowest density, and the density averaged 307.4 kg/m3. Additionally, for the sample containing 5 wt.% basalt powder, the compressive strength exceeded 1.4 MPa, and the thermal conductivity coefficient was 0.1108 W/m × K. The effect of basalt powder in geopolymer foams can vary depending on many factors, such as its chemical composition, grain size, content, and physical properties. The addition of basalt above 10% causes a decrease in the significant properties of the geopolymer. Full article
17 pages, 4655 KiB  
Article
Design of Mixed-Mode Analog PID Controller with CFOAs
by Natchanai Roongmuanpha, Jetsdaporn Satansup, Tattaya Pukkalanun and Worapong Tangsrirat
Sensors 2024, 24(10), 3125; https://doi.org/10.3390/s24103125 (registering DOI) - 14 May 2024
Abstract
The design of a mixed-mode proportional-integral-derivative (PID) controller circuit using current-feedback operational amplifiers (CFOAs) as active components is proposed. With the same circuit topology, the proposed configuration of three CFOAs, four resistors, and two capacitors is capable of performing the PID controller in [...] Read more.
The design of a mixed-mode proportional-integral-derivative (PID) controller circuit using current-feedback operational amplifiers (CFOAs) as active components is proposed. With the same circuit topology, the proposed configuration of three CFOAs, four resistors, and two capacitors is capable of performing the PID controller in each of the following four modes: voltage mode, trans-admittance mode, current mode, and trans-impedance mode. Numerous mathematical analyses are conducted to determine the controller’s performance under both ideal and non-ideal conditions. Additionally, the mixed-mode second-order lowpass filter is suggested and also used to examine the workability of the proposed mixed-mode PID controller in a feedback control structure. The proposed PID controller is implemented with the commercially available IC-type CFOA AD844, and the simulation results are presented to illustrate the functionality of the controller and its closed-loop control system. According to the findings, the total power consumption of the proposed PID controller is 0.348 W, with symmetrical supply voltages of ±9 V. It also has a temperature variation of less than 0.2% over the AD844’s usable range. Monte Carlo statistical analysis results revealed that the gain responses of the controller exhibited a deviation of no more than 7.72% from the theoretical value. The controlled filter in a closed-loop control system has a 43% faster rise time and peak time than the uncontrolled filter in all four modes of operation. It also has a steady-state error less than 0.2 mV for voltage responses and 0.72 µA for current responses. Full article
(This article belongs to the Section Electronic Sensors)
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14 pages, 8891 KiB  
Article
Improving Thermal Performance in Data Centers Based on Numerical Simulations
by Yinjie Guo, Chunyu Zhao, Hao Gao, Cheng Shen and Xu Fu
Buildings 2024, 14(5), 1416; https://doi.org/10.3390/buildings14051416 (registering DOI) - 14 May 2024
Abstract
(1) Background: With the rapid development of cloud computing, large AI models, and other emerging technologies, the issue of heat dissipation in data centers has become increasingly prominent. This issue is often caused by inappropriate temperature distribution when using cold air to cool [...] Read more.
(1) Background: With the rapid development of cloud computing, large AI models, and other emerging technologies, the issue of heat dissipation in data centers has become increasingly prominent. This issue is often caused by inappropriate temperature distribution when using cold air to cool servers. Improving temperature distribution is key to optimizing the thermal performance of data centers. Previous solutions do not include installing adjustable underfloor deflectors under a raised floor while adjusting the aperture ratio of the floor grille and replacing the side of the floor grille located near the air-conditioning unit with a fan floor. (2) Methods: A 3D model of a data center was established, and its meshing and boundary conditions were set. The airflow inside the data center was analyzed using a CFD simulation to assess the temperature distribution resulting from two proposed solutions. (3) Results: Simulations and analyses showed that both options balanced the airflow close to and away from the conditioned side cabinets. This maximized the cooling capacity and improved temperature uniformity. The maximum temperature drop registered for the average cabinet’s out temperature was 2.81 °C. And by installing an adjustable underfloor deflector under the floor grille in rows O and N and adjusting the grille opening, the airflow to the cabinet near the air-conditioned side increased by 18.1%, and the airflow away from the air-conditioned side decreased by 5.1%. Similarly, replacing the Q-row floor grille with a fan floor resulted in a 4.9% increase in airflow to the cabinet near the air-conditioning side and a 3.8% decrease in airflow to the cabinet away from the air-conditioning side. (4) Conclusions: Airflow is a crucial factor that affects cabinet temperature. And balancing airflow between the front-end and rear-end cabinets is essential to make the best use of the cooling capacity and improve temperature distribution within data-center cabinets. This can be achieved by installing a fan floor and an underfloor deflector device in front of high-temperature cabinets located near air-conditioning units. Full article
(This article belongs to the Section Building Energy, Physics, Environment, and Systems)
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19 pages, 3118 KiB  
Article
Surface Deformation Calculation Method Based on Displacement Monitoring Data
by Lin He and Yibin Yao
Buildings 2024, 14(5), 1417; https://doi.org/10.3390/buildings14051417 (registering DOI) - 14 May 2024
Abstract
Considering the importance of calculating surface deformation based on monitoring data, this paper proposes a method for calculating horizontal deformation based on horizontal displacement monitoring data. This study first analyzes the characteristics of horizontal displacement monitoring data, then proposes a scheme for obtaining [...] Read more.
Considering the importance of calculating surface deformation based on monitoring data, this paper proposes a method for calculating horizontal deformation based on horizontal displacement monitoring data. This study first analyzes the characteristics of horizontal displacement monitoring data, then proposes a scheme for obtaining the surface horizontal displacement field through corresponding discrete point interpolation. Subsequently, the calculation method for surface horizontal strain is introduced, along with relevant examples. The study also systematically summarizes the calculation methods for surface curvature and surface tilt deformation values, forming a set of surface deformation calculation methods based on monitoring data. The research results indicate that when there is a large number of on-site monitoring points, effective monitoring points can be selected based on the direction of horizontal displacement. When interpolating the surface horizontal displacement field, the interpolation accuracy of the radial basis function method is slightly higher than that of ordinary Kriging. The form of coordinate expression has a significant impact on interpolation accuracy. The accuracy of interpolation using horizontal displacement vectors expressed in polar coordinates is higher than that using vectors expressed in Cartesian coordinates. The calculated surface horizontal strain has effective upper and lower limits, with lower-limit strain on the contour line conforming to the typical surface deformation patterns around mined-out areas. Full article
19 pages, 7477 KiB  
Article
Effect of Asphaltenes and Asphaltene Dispersants on Wax Precipitation and Treatment
by Oualid M’barki, John Clements and Quoc P. Nguyen
Colloids Interfaces 2024, 8(3), 30; https://doi.org/10.3390/colloids8030030 (registering DOI) - 14 May 2024
Abstract
A detailed understanding of the interactions between wax and asphaltenes with other components of crude oils and the effect of treatments with paraffin inhibitors (PIs) and asphaltene dispersants (ADs), with a focus on identifying specific structure-activity relationships, is necessary to develop effective flow [...] Read more.
A detailed understanding of the interactions between wax and asphaltenes with other components of crude oils and the effect of treatments with paraffin inhibitors (PIs) and asphaltene dispersants (ADs), with a focus on identifying specific structure-activity relationships, is necessary to develop effective flow assurance strategies. The morphological and rheological consequences of treating wax and asphaltenes in oils of differing composition with a series of ADs having structural features in common with an alpha olefin-maleic anhydride (AO-MA) comb-like copolymer PI were assessed alone and in combination with said PI. Of the four ADs studied, two were identified as being effective dispersants of asphaltenes in heptane-induced instability tests and in a West Texas (WT) crude. The degree to which a low concentration of asphaltenes stabilizes wax in the absence of treatment additives is lessened in oils having greater aromatic fractions. This is because these stabilizing interactions are replaced by more energetically favorable aromatic–asphaltene interactions, increasing oil viscosity. Treatment with AD alone also reduces the extent of wax–asphaltene interactions, increasing oil viscosity. In concert with the PI, treatment with the AD having greater structural similarity with the PI appears to improve wax solubility in both the presence and absence of asphaltenes. However, the viscosity of the treated oils is greater than that of the oil treated with PI alone, while treatment with AD having lesser structural similarity with the PI does not adversely affect oil viscosity. These data suggest that rather than treating both wax and asphaltenes, AD may poison the function of the PI. These data illuminate the pitfalls of designing flow assurance additives to interact with both wax and asphaltenes and developing treatment plans. Full article
(This article belongs to the Special Issue Crude Oil Recovery)
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18 pages, 8711 KiB  
Article
Geochemical Characteristics and U–Pb Dating of Granites in the Western Granitoid Belt of Thailand
by Etsuo Uchida, Takumi Yokokura, Sota Niki and Takafumi Hirata
Geosciences 2024, 14(5), 135; https://doi.org/10.3390/geosciences14050135 (registering DOI) - 14 May 2024
Abstract
This paper presents the integration of magnetic susceptibility measurements and whole-rock geochemical compositional and Nd–Sr isotopic ratio analyses for granite samples collected from the Ranong, Lam Pi, Ban Lam Ru, and Phuket granite bodies in the Western Granitoid Belt of Thailand. In addition, [...] Read more.
This paper presents the integration of magnetic susceptibility measurements and whole-rock geochemical compositional and Nd–Sr isotopic ratio analyses for granite samples collected from the Ranong, Lam Pi, Ban Lam Ru, and Phuket granite bodies in the Western Granitoid Belt of Thailand. In addition, U–Pb dating was performed on zircons extracted from the samples. All samples are proper granites based on their mineralogical and geochemical characteristics. Two samples collected from the Lam Pi granite body were classified as magnetite-series and I-type. The remaining granite samples were classified as ilmenite-series and S- or A-type. Furthermore, all granites were classified as syn-collision granites. Excluding the magnetite-series samples from the Lam Pi granite body, the other samples exhibit enrichment in incompatible elements, such as Nb, Sn, Ta, Pb, Bi, Th, U, Ce, Rb, and Cs. Zircon U–Pb dating yielded ages of ca. 60 Ma for the magnetite-series granites from the Lam Pi granite body, whereas ages of 88–84 Ma were obtained for the other granite bodies. Initial Nd–Sr isotopic ratios indicate a higher contribution of mantle material in the Lam Pi magnetite-series granites and a higher contribution of continental crust material in the other granites. Based on these compositional and zircon U–Pb age data, it is inferred that the 88–84 Ma granites formed as a result of the thickening of the continental crust owing to the collision between the Sibumasu and the West Burma blocks. In contrast, the ca. 60 Ma Lam Pi magnetite-series granites are thought to have been generated via partial melting of the mantle wedge associated with the subduction of the Neo-Tethyan oceanic crust beneath the West Burma Block. Full article
(This article belongs to the Section Geochemistry)
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12 pages, 299 KiB  
Article
Assessing Nutritional Status in Gastric Cancer Patients after Total versus Subtotal Gastrectomy: Cross-Sectional Study
by Fawzy Akad, Bogdan Filip, Cristina Preda, Florin Zugun-Eloae, Sorin Nicolae Peiu, Nada Akad, Dragos-Valentin Crauciuc, Ruxandra Vatavu, Liviu-Ciprian Gavril, Roxana-Florentina Sufaru and Veronica Mocanu
Nutrients 2024, 16(10), 1485; https://doi.org/10.3390/nu16101485 (registering DOI) - 14 May 2024
Abstract
Gastric cancer (GC) remains a significant global health concern, ranking as the third leading cause of cancer-related deaths. Malnutrition is common in GC patients and can negatively impact prognosis and quality of life. Understanding nutritional issues and their management is crucial for improving [...] Read more.
Gastric cancer (GC) remains a significant global health concern, ranking as the third leading cause of cancer-related deaths. Malnutrition is common in GC patients and can negatively impact prognosis and quality of life. Understanding nutritional issues and their management is crucial for improving patient outcomes. This cross-sectional study included 51 GC patients who underwent curative surgery, either total or subtotal gastrectomy. Various nutritional assessments were conducted, including anthropometric measurements, laboratory tests, and scoring systems such as Eastern Cooperative Oncology Group/World Health Organization Performance Status (ECOG/WHO PS), Observer-Reported Dysphagia (ORD), Nutritional Risk Screening-2002 (NRS-2002), Patient-Generated Subjective Global Assessment (PG-SGA), and Simplified Nutritional Appetite Questionnaire (SNAQ). Serum carcinoembryonic antigen (CEA) levels were significantly higher in the subtotal gastrectomy group. Nutritional assessments indicated a higher risk of malnutrition in patients who underwent total gastrectomy, as evidenced by higher scores on ORD, NRS-2002, and PG-SGA. While total gastrectomy was associated with a higher risk of malnutrition, no single nutritional parameter emerged as a strong predictor of surgical approach. PG-SGA predominantly identified malnutrition, with its occurrence linked to demographic factors such as female gender and age exceeding 65 years. Full article
10 pages, 481 KiB  
Systematic Review
The Prevalence of Caregiving among Young People
by Lawrence T. Lam and Mary K. Lam
Int. J. Environ. Res. Public Health 2024, 21(5), 621; https://doi.org/10.3390/ijerph21050621 (registering DOI) - 14 May 2024
Abstract
With the increasing number of people with chronic diseases and disabilities, the number of family members as caregivers have also been growing. Despite the attention paid to caregiving in recent years, little is known about caregiving among young people, particularly its global prevalence. [...] Read more.
With the increasing number of people with chronic diseases and disabilities, the number of family members as caregivers have also been growing. Despite the attention paid to caregiving in recent years, little is known about caregiving among young people, particularly its global prevalence. The lack of information has important implications for health policy and management, resulting in the inability to form appropriate evidence-based policies and managerial decision making. This study aims to derive an estimate of the prevalence of caregiving among young people through a systematic review of the current literature. The results of this study revealed a prevalence of caregiving among younger adolescents of between 1.1% (1.06–1.14%) and 12.0% (11.02–12.98%). However, the assessment of caregiving varies across studies, and all were conducted in developed countries. These results provide information on the burden of caregiving in young people and reveal the lack of global information, calling for more research on and attention to this specific population. Full article
14 pages, 1882 KiB  
Article
Friction-Wear and Noise Characteristics of Friction Disks with Circular Texture
by Biao Ma, Weichen Lu, Liang Yu, Cenbo Xiong, Guoqiang Dang and Xiaobo Chen
Materials 2024, 17(10), 2337; https://doi.org/10.3390/ma17102337 (registering DOI) - 14 May 2024
Abstract
The reduction of friction-induced noise is a crucial research area for enhancing vehicle comfort, and this paper proposes a method based on circular pit texture to achieve this goal. We conducted a long-term sliding friction test using a pin-on-disc friction and a wear [...] Read more.
The reduction of friction-induced noise is a crucial research area for enhancing vehicle comfort, and this paper proposes a method based on circular pit texture to achieve this goal. We conducted a long-term sliding friction test using a pin-on-disc friction and a wear test bench to verify the validity of this method. To compare the friction noise of different surfaces, texture units with varying line densities were machined on the surface of friction disk samples. The resulting friction-wear and noise characteristics of the samples were analyzed in conjunction with the microscopic morphology of the worn surfaces. The results indicate that surfaces with textures can delay the onset of squeal noise, and the pattern of its development differs from that of smooth surfaces. The noise reduction effect is most evident due to the proper distribution of textures that can form furrow-like wear marks at the wear interface. The finite element results demonstrate that this morphology can improve pressure distribution at the leading point and reduce the tendency of system instability. Full article
(This article belongs to the Special Issue Evolution of the Working Performance of Special Materials)
22 pages, 3452 KiB  
Article
Corrosion Behavior of Ni-Cr Alloys with Different Cr Contents in NaCl-KCl-MgCl2
by Peng Lei, Lizhen Zhou, Yu Zhang, Fuli Wang, Qinzhe Li, Jiangyan Liu, Xueyun Xiang, Hang Wu, Wen Wang and Fuhui Wang
Materials 2024, 17(10), 2335; https://doi.org/10.3390/ma17102335 (registering DOI) - 14 May 2024
Abstract
This study investigates the corrosion behavior of Ni-Cr binary alloys, including Ni-10Cr, Ni-15Cr, Ni-20Cr, Ni-25Cr, and Ni-30Cr, in a NaCl-KCl-MgCl2 molten salt mixture through gravimetric analysis. Corrosion tests were conducted at 700 °C, with the maximum immersion time reaching up to 100 [...] Read more.
This study investigates the corrosion behavior of Ni-Cr binary alloys, including Ni-10Cr, Ni-15Cr, Ni-20Cr, Ni-25Cr, and Ni-30Cr, in a NaCl-KCl-MgCl2 molten salt mixture through gravimetric analysis. Corrosion tests were conducted at 700 °C, with the maximum immersion time reaching up to 100 h. The corrosion rate was determined by measuring the mass loss of the specimens at various time intervals. Verifying corrosion rates by combining mass loss results with the determination of element dissolution in molten salts using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Detailed examinations of the corrosion products and morphology were conducted using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Micro-area elemental analysis on the corroded surfaces was performed using an energy dispersive spectrometer (EDS), and the elemental distribution across the corrosion cross-sections was mapped. The results indicate that alloys with lower Cr content exhibit superior corrosion resistance in the NaCl-KCl-MgCl2 molten salt under an argon atmosphere compared to those with higher Cr content; no corrosion products were retained on the surfaces of the lower Cr alloys (Ni-10Cr, Ni-15Cr). For the higher Cr alloys (Ni-20Cr, Ni-25Cr, Ni-30Cr), after 20 h of corrosion, a protective layer was observed in certain areas. The formation of a stable Cr2O3 layer in the initial stages of corrosion for high-Cr content alloys, which reacts with MgO in the molten salt to form a stable MgCr2O4 spinel structure, provides additional protection for the alloys. However, over time, even under argon protection, the MgCr2O4 protective layer gradually degrades due to chloride ion infiltration and chemical reactions at high temperatures. Further analysis revealed that chloride ions play a pivotal role in the corrosion process, not only facilitating the destruction of the Cr2O3 layer on the alloy surfaces but also possibly accelerating the corrosion of the metallic matrix through electrochemical reactions. In conclusion, the corrosion behavior of Ni-Cr alloys in the NaCl-KCl-MgCl2 molten salt environment is influenced by a combination of factors, including Cr content, chloride ion activity, and the formation and degradation of protective layers. This study not only provides new insights into the corrosion resistance of Ni-Cr alloys in high-temperature molten salt environments but also offers significant theoretical support for the design and optimization of corrosion-resistant alloy materials. Full article
(This article belongs to the Special Issue Corrosion Mechanism and Protection Technology of Metallic Materials)
23 pages, 5807 KiB  
Article
Experimental Investigation and Design of Novel Hollow Flange Beams under Bending
by Jingya Xue, Shiliang Ma, Xiaomiao Chen, Qing Wu, Yifan Wang, Yunqing Wang, Muhammad Akbar and Ning Yang
Buildings 2024, 14(5), 1413; https://doi.org/10.3390/buildings14051413 (registering DOI) - 14 May 2024
Abstract
In this paper, a new type of assembling rivet-fastened rectangular hollow flange beams (ARHFBs) is proposed. The cross-section of the ARHFB consists of two U-shaped and C-shaped components connected by self-locking rivets to form two rectangular hollow flanges. To study the performance and [...] Read more.
In this paper, a new type of assembling rivet-fastened rectangular hollow flange beams (ARHFBs) is proposed. The cross-section of the ARHFB consists of two U-shaped and C-shaped components connected by self-locking rivets to form two rectangular hollow flanges. To study the performance and strength of the ARHFB as a flexural member, eight four-point bending tests and more than 40 simulation studies were carried out. The details, results, and comparison of the four-point bending tests, especially the characteristics of the test bench and the lateral support, are presented in this paper. ARHFB sections with varied rivet spacing, web depth, and flange width were experimentally studied. Additionally, a parametric study of ARHFB was conducted using finite element models verified by test results. The influence of span on the loading capacity of ARHFB was discussed. ARHFB can be used in large-span buildings. A more economical ARHFB component selection method was given. The depth of the flange, the strength of the web, and the thickness of the web are important parameters of ARHFB. The loading capacity obtained from the test was compared with the predicted values of the design formulas in the American Iron and Steel Institute (AISI) and the Chinese design standard for cold-rolled steel (GB50018). The calculation and verification of ARHFB flange buckling and lateral torsional buckling were also considered. It is recommended that GB50018 be used to predict the flexural capacity of ARHFBs. Full article
(This article belongs to the Section Building Structures)
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16 pages, 683 KiB  
Article
Evaluation of Edible Coatings from Components from Chlorella vulgaris and Comparison with Conventional Coatings
by Alexandra Mari, Charilaos Fafalis and Magdalini Krokida
Coatings 2024, 14(5), 621; https://doi.org/10.3390/coatings14050621 (registering DOI) - 14 May 2024
Abstract
The present customer demand for ready-to-eat food items with higher nutritious value and longer shelf life necessitates creative solutions. An edible coating is a sustainable packaging solution that can prevent food deterioration and preserve food quality. Proteins, starch, and the addition of plasticizers [...] Read more.
The present customer demand for ready-to-eat food items with higher nutritious value and longer shelf life necessitates creative solutions. An edible coating is a sustainable packaging solution that can prevent food deterioration and preserve food quality. Proteins, starch, and the addition of plasticizers are used to create edible coatings. The aim of this study was to develop coating solutions that can best preserve food using isolated starch and proteins from Chlorella vulgaris, and then compare them to coatings that comprise conventional ingredients like chitosan and starch. A number of criteria pertaining to the coatings’ mechanical, optical, thermal, and physical properties were tested. The alternative coatings performed just as well as the conventional ones, with the protein algal coating exhibiting the best thermal, optical, and physical qualities. The food product that needs to be coated can determine which coating is ideal. In conclusion, edible coatings derived from Chlorella vulgaris offer a sustainable solution to preserve ready-to-eat food items, showcasing comparable performance to conventional coatings. Full article
(This article belongs to the Section Coatings for Food Technology and System)
21 pages, 7901 KiB  
Article
Assessing the Feasibility of Removing Graffiti from Railway Vehicles Using Ultra-Freezing Air Projection
by Aina Vega-Bosch, Virginia Santamarina-Campos, Pilar Bosch-Roig, Juan Antonio López-Carrillo, Vicente Dolz-Ruiz and Mercedes Sánchez-Pons
Appl. Sci. 2024, 14(10), 4165; https://doi.org/10.3390/app14104165 (registering DOI) - 14 May 2024
Abstract
Unauthorised graffiti is a challenge in urban environments, affecting railway structures, stations, tracks, and vehicles. Inefficient cleaning methods increase the costs and downtime of railcars, limiting passenger transport. In turn, they are harmful to the operator’s health and the environment, due to the [...] Read more.
Unauthorised graffiti is a challenge in urban environments, affecting railway structures, stations, tracks, and vehicles. Inefficient cleaning methods increase the costs and downtime of railcars, limiting passenger transport. In turn, they are harmful to the operator’s health and the environment, due to the VOCs they release. This study focuses on the feasibility of dry-ice blasting, replacing carbon dioxide with ambient air as an innovative and sustainable solution to remove graffiti from rail vehicles. Experimental tests have been carried out with 13 different aerosols, controlling the temperature (<−80 °C), pressure (up to 3 bar), projection distance (0.5 cm) and exposure times (30″/1′/2′/4′/6′/8′/++). The results showed that ultra-freezing with ambient air preserved the integrity of the support materials and altered the topography, colourimetry and adhesion of the aerosols tested, achieving the total removal of one of the paints. Preliminary results suggest that ultra-freezing with ambient air could be a viable and sustainable solution for graffiti removal on railway structures, transferable to other urban environments. Full article
17 pages, 414 KiB  
Article
Determinants of Weight Status and Body, Health and Life Satisfaction in Young Adults
by Julia Suwalska, Sylwia Łukasik, Maciej Cymerys, Aleksandra Suwalska and Paweł Bogdański
Nutrients 2024, 16(10), 1484; https://doi.org/10.3390/nu16101484 (registering DOI) - 14 May 2024
Abstract
Health behaviors include behavioral patterns and habits that relate to health maintenance, restoration and improvement. They do not only affect the physical condition; they are also associated with life satisfaction. In our study, we focused on young adulthood, a specific lifespan period for [...] Read more.
Health behaviors include behavioral patterns and habits that relate to health maintenance, restoration and improvement. They do not only affect the physical condition; they are also associated with life satisfaction. In our study, we focused on young adulthood, a specific lifespan period for establishing long-term health behavior patterns. The aim of the present study was to investigate depressive symptoms, lifestyle and eating behaviors and delineate their associations with overweight/obesity and body, health and life satisfaction in young adults in Poland. We enrolled 800 students (81.4% females and 18.6% males). Diet, physical activity, depressive symptoms, eating behaviors and body, health and life satisfaction were assessed. Multivariate logistic regression models were employed. Almost half of the participants in our study had at least mild symptoms of depression. Symptoms of depression significantly reduced the odds of satisfaction with body, health and life, whereas physical activity increased them. Overweight/obesity significantly reduced the odds of body and health satisfaction. In women, a history of depression and emotional eating increased the odds of being overweight/obese. The results of our study may contribute to the development of educational programs and intervention strategies for young adults. Full article
(This article belongs to the Special Issue Public Health, Nutritional Behavior and Nutritional Status)
19 pages, 44211 KiB  
Article
Algal Bed Region Segmentation Based on a ViT Adapter Using Aerial Images for Estimating CO2 Absorption Capacity
by Guang Li, Ren Togo, Keisuke Maeda, Akinori Sako, Isao Yamauchi, Tetsuya Hayakawa, Shigeyuki Nakamae, Takahiro Ogawa and Miki Haseyama
Remote Sens. 2024, 16(10), 1742; https://doi.org/10.3390/rs16101742 (registering DOI) - 14 May 2024
Abstract
In this study, we propose a novel method for algal bed region segmentation using aerial images. Accurately determining the carbon dioxide absorption capacity of coastal algae requires measurements of algal bed regions. However, conventional manual measurement methods are resource-intensive and time-consuming, which hinders [...] Read more.
In this study, we propose a novel method for algal bed region segmentation using aerial images. Accurately determining the carbon dioxide absorption capacity of coastal algae requires measurements of algal bed regions. However, conventional manual measurement methods are resource-intensive and time-consuming, which hinders the advancement of the field. To solve these problems, we propose a novel method for automatic algal bed region segmentation using aerial images. In our method, we use an advanced semantic segmentation model, a ViT adapter, and adapt it to aerial images for algal bed region segmentation. Our method demonstrates high accuracy in identifying algal bed regions in an aerial image dataset collected from Hokkaido, Japan. The experimental results for five different ecological regions show that the mean intersection over union (mIoU) and mean F-score of our method in the validation set reach 0.787 and 0.870, the IoU and F-score for the background region are 0.957 and 0.978, and the IoU and F-score for the algal bed region are 0.616 and 0.762, respectively. In particular, the mean recognition area compared with the ground truth area annotated manually is 0.861. Our study contributes to the advancement of blue carbon assessment by introducing a novel semantic segmentation-based method for identifying algal bed regions using aerial images. Full article
13 pages, 8609 KiB  
Article
A Li-Ion Battery State of Charge Estimation Strategy Based on the Suboptimal Multiple Fading Factor Extended Kalman Filter Algorithm
by Weibin Wu, Jinbin Zeng, Qifei Jian, Luxin Tang, Junwei Hou, Chongyang Han, Qian Song and Yuanqiang Luo
Processes 2024, 12(5), 998; https://doi.org/10.3390/pr12050998 (registering DOI) - 14 May 2024
Abstract
The state of charge (SOC) is an important indicator for evaluating a battery management system (BMS), which is crucial for the reliability, performance, and life management of a battery. In this paper, the characteristics of a Li-ion battery are deeply studied to explore [...] Read more.
The state of charge (SOC) is an important indicator for evaluating a battery management system (BMS), which is crucial for the reliability, performance, and life management of a battery. In this paper, the characteristics of a Li-ion battery are deeply studied to explore the charge/discharge curve under different environments. Meanwhile, a second-order RC equivalent circuit model is constructed. The function identification of the EMF and SOC is performed based on the least squares method. The model estimation error is verified by simulation to be less than 0.05 V. Based on the Suboptimal Multiple Fading Factor Extended Kalman Filter (SMFEKF) algorithm, the SOC under constant current and UDDS conditions are estimated. Matlab/simulink simulations illustrate that the estimated accuracy of the proposed algorithm is improved by 79.36% compared with the EKF algorithm. Finally, the validity of the algorithm is verified jointly with the BMS. The results show that the estimation error is within 4% in both constant current condition as well as UDDS conditions, and it can still be predicted quickly and accurately under the uncertainty in the initial value of the SOC. Full article
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11 pages, 268 KiB  
Article
New Oscillation Criteria for Sturm–Liouville Dynamic Equations with Deviating Arguments
by Taher S. Hassan, Clemente Cesarano, Loredana Florentina Iambor, Amir Abdel Menaem, Naveed Iqbal and Akbar Ali
Mathematics 2024, 12(10), 1532; https://doi.org/10.3390/math12101532 (registering DOI) - 14 May 2024
Abstract
The aim of this study is to refine the known Riccati transformation technique to provide new oscillation criteria for solutions to second-order dynamic equations over time. It is important to note that the convergence or divergence of some improper integrals on time scales [...] Read more.
The aim of this study is to refine the known Riccati transformation technique to provide new oscillation criteria for solutions to second-order dynamic equations over time. It is important to note that the convergence or divergence of some improper integrals on time scales depends not only on the integration function but also on the integration time scale. Therefore, there has been a motivation to find new oscillation criteria that can be applicable regardless of whether ζ0Δξa(ξ) is convergent or divergent, in contrast to what has been followed in most previous works in the literature. We have provided an example to illustrate the significance of the obtained results. Full article
25 pages, 19292 KiB  
Article
Expressing the Spatial Concepts of Interior Spaces in Residential Buildings of Huizhou, China: Narrative Methods of Wood-Carving Imagery
by Xuebing Fang, Lili Li, Yi Gao, Niu Liu and Liangsong Cheng
Buildings 2024, 14(5), 1414; https://doi.org/10.3390/buildings14051414 (registering DOI) - 14 May 2024
Abstract
In the interiors of ancient Huizhou buildings in China, a profusion of wood carvings are employed for decoration, with traditional research interpreting their function from decorative and aesthetic perspectives. However, this research suggests that the role of Huizhou wood carvings in interior spaces [...] Read more.
In the interiors of ancient Huizhou buildings in China, a profusion of wood carvings are employed for decoration, with traditional research interpreting their function from decorative and aesthetic perspectives. However, this research suggests that the role of Huizhou wood carvings in interior spaces surpasses mere decoration; they enhance the expression and experience of spatial concepts through narrative imagery. By analyzing the mechanism and intrinsic logic behind the spatial concepts formed in Huizhou residential buildings, this study investigates how wood-carving imagery contributes to shaping spatial concepts through narrative techniques, as well as their creativity and expressiveness in architectural design. Utilizing literature reviews, field surveys for case selection, and case analysis methods combined with observation, interviews, and measurements, this research ultimately employs image analysis to interpret the narrative structures and styles of wood-carving imagery in detail. This study reveals that (1) the spatial concepts of Huizhou residential buildings are influenced by traditional thought, social culture, and other factors, leading to an interweaving of material, cultural, and social spaces that results in a spatial concept characterized by harmony between heaven and humanity, clear hierarchy, and orderliness; (2) Huizhou wood-carvings, through their narrative images, actively engage in the production of spatial concepts, employing thematic juxtaposition narrative modes and utilizing singular-scene narration, composite-scene narration, and cyclical narration to articulate these concepts. These findings significantly deepen our comprehension of the relationship between the spatial concepts of Huizhou’s traditional residential architecture and social culture. By integrating cultural elements with spatial production theory, this research addresses the limitations of existing studies and augments their theoretical interpretative power. Additionally, clarifying the connection between the cultural elements of wood-carving imagery and the formation of spatial concepts offers a novel perspective on the study of Huizhou wood carvings, moving beyond their longstanding categorization as purely decorative elements. Full article
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27 pages, 7596 KiB  
Article
Achievement of a Parameter Window for the Selective Laser Melting Formation of a GH3625 Alloy
by Guozheng Quan, Qi Deng, Yifan Zhao, Mingguo Quan and Daijian Wu
Materials 2024, 17(10), 2333; https://doi.org/10.3390/ma17102333 (registering DOI) - 14 May 2024
Abstract
In the selective laser melting (SLM) process, adjusting process parameters contributes to achieving the desired molten pool morphology, thereby enhancing the mechanical properties and dimensional accuracy of manufactured components. The parameter window characterizing the relationship between molten pool morphology and process parameters serves [...] Read more.
In the selective laser melting (SLM) process, adjusting process parameters contributes to achieving the desired molten pool morphology, thereby enhancing the mechanical properties and dimensional accuracy of manufactured components. The parameter window characterizing the relationship between molten pool morphology and process parameters serves as an effective tool to improve SLM’s forming quality. This work established a mesoscale model of the SLM process for a GH3625 alloy based on the discrete element method (DEM) and computational fluid dynamics (CFD) to simulate the forming process of a single molten track. Subsequently, the formation mechanism and evolution process of the molten pool were revealed. The effects of laser power and scanning speed on the molten pool size and molten track morphology were analyzed. Finally, a parameter window was established from the simulation results. The results indicated that reducing the scanning speed and increasing the laser power would lead to an increase in molten pool depth and width, resulting in the formation of an uneven width in the molten track. Moreover, accelerating the scanning speed and decreasing the laser power cause a reduction in molten pool depth and width, causing narrow and discontinuous molten tracks. The accuracy of the simulation was validated by comparing experimental and simulated molten pool sizes. Full article
(This article belongs to the Special Issue Additive Processing of High-Temperature Alloys)

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