The 2023 MDPI Annual Report has
been released!
 
18 pages, 556 KiB  
Article
Enhancing Rural Revitalization in China through Digital Economic Transformation and Green Entrepreneurship
by Ying Wang and Daoliang Ye
Sustainability 2024, 16(10), 4147; https://doi.org/10.3390/su16104147 (registering DOI) - 15 May 2024
Abstract
Over the past few years, rural revitalization has become a focal point of interest in the discourse of sustainable development. However, there exists a gap in understanding the factors that foster economic sustainability in rural settings. The current study seeks to investigate the [...] Read more.
Over the past few years, rural revitalization has become a focal point of interest in the discourse of sustainable development. However, there exists a gap in understanding the factors that foster economic sustainability in rural settings. The current study seeks to investigate the influence of digital economic transformation on rural revitalization in the context of China by employing a serial mediation model encompassing green entrepreneurship and green innovation. Data were collected from rural entrepreneurs using a stratified sampling method, with strata identified based on geographical and socioeconomic factors, which allowed for a comprehensive examination of various business sizes and stages across sectors. The authors analyzed the structural paths using multivariate analytical techniques by utilizing SmartPLS-SEM. The empirical findings provide support to the hypothesized relationships that: (1) digital economic transformation significantly promotes green entrepreneurship, which in turn, cultivates green innovation; and (2) green entrepreneurship and green innovation serially mediate the association between digital economic transformation and rural revitalization. Our study provides a holistic model that can inform regulatory frameworks and governmental strategies to support sustainable rural development in China. Full article
4 pages, 286 KiB  
Editorial
Combined Treatments and Therapies to Cure Spinal Cord Injury
by Nicolas Guérout
Biomedicines 2024, 12(5), 1095; https://doi.org/10.3390/biomedicines12051095 (registering DOI) - 15 May 2024
Abstract
Traumatic injuries of the spinal cord (SCIs) are still pathologies with a disastrous outcome [...] Full article
(This article belongs to the Special Issue Combined Treatments and Therapies to Cure Spinal Cord Injury)
21 pages, 3446 KiB  
Article
Theoretical and Experimental Investigations of Identifying Bridge Damage Using Instantaneous Amplitude Squared Extracted from Vibration Responses of a Two-Axle Passing Vehicle
by Siying Liu, Zunian Zhou, Yujie Zhang, Zhuo Sun, Jiangdong Deng and Junyong Zhou
Buildings 2024, 14(5), 1428; https://doi.org/10.3390/buildings14051428 (registering DOI) - 15 May 2024
Abstract
Identifying bridge damage using a movable test vehicle is highly regarded for its mobility, cost-effectiveness, and broad monitoring coverage. Previous studies have shown that the residual contact-point (CP) response between connected vehicles is free of the impact of vehicle self-vibrations and road roughness, [...] Read more.
Identifying bridge damage using a movable test vehicle is highly regarded for its mobility, cost-effectiveness, and broad monitoring coverage. Previous studies have shown that the residual contact-point (CP) response between connected vehicles is free of the impact of vehicle self-vibrations and road roughness, making it particularly suitable for the indirect extraction of bridge modal properties. However, most experimental campaigns regarding contact-point (CP) responses focus on a single-axle testing vehicle within a non-moving state. This study aims to theoretically and experimentally identify bridge damage using the instantaneous amplitude squared (IAS) extracted from the residual CP response of a two-axle passing vehicle. First, the closed-form solution of the residual CP acceleration was derived for a two-axle vehicle interacting with a simply supported beam. The IAS index was constructed from the driving frequency of the residual CP acceleration. Then, numerical investigations using finite element simulation were conducted to validate using the IAS index for indirect bridge damage identification. The application scope of the approach under various vehicle speeds and road roughness grades was examined. Finally, a laboratory vehicle–bridge interaction system was tested to validate the approach. Numerical studies demonstrated that bridge damage could be directly determined by observing the IAS abnormalities, which were baseline-free. The IAS from the residual CP response outperformed the IAS from CP responses in identifying bridge damage. However, it was better to use the IAS when the vehicle speed was no greater than 2 m/s and the grade of the road surface roughness was not high. Laboratory tests showed that it was possible to identify bridge damage using the IAS extracted from the residual CP acceleration under perfect road surfaces. However, it fell short under rough road surfaces. Hence, further experiments are required to fully examine the capacity of the IAS for bridge damage identification in practical applications. Full article
(This article belongs to the Special Issue Advances in Research on Structural Dynamics and Health Monitoring)
16 pages, 2134 KiB  
Article
A Novel Positional Calibration Method for an Underwater Acoustic Beacon Array Based on the Equivalent Virtual Long Baseline Positioning Model
by Ge Zhang, Guoxing Yi, Zhennan Wei, Yangguang Xie and Ziyang Qi
J. Mar. Sci. Eng. 2024, 12(5), 825; https://doi.org/10.3390/jmse12050825 (registering DOI) - 15 May 2024
Abstract
The performance of long baseline (LBL) positioning systems is significantly impacted by the distribution and positional calibration accuracy of underwater acoustic beacon arrays. In previous calibration methods for beacon arrays based on autonomous underwater vehicle (AUV) platforms, the slant range information of each [...] Read more.
The performance of long baseline (LBL) positioning systems is significantly impacted by the distribution and positional calibration accuracy of underwater acoustic beacon arrays. In previous calibration methods for beacon arrays based on autonomous underwater vehicle (AUV) platforms, the slant range information of each beacon was processed independently, and each beacon was calibrated one at a time. This approach not only decreases the calibration efficiency but also leaves the positional calibration accuracy of each beacon highly susceptible to the navigation trajectory of the AUV. To overcome these limitations, an equivalent virtual LBL (EVLBL) positioning model is introduced in this paper. This model operates by adjusting the positions of each beacon according to the dead reckoning increments computed during the AUV’s reception of positioning signals, effectively forming a virtual beacon array. Consequently, the AUV is capable of mitigating LBL positioning errors that arise from its motion by simultaneously receiving positioning signals from all beacons. Additionally, an overall calibration method for beacon arrays based on particle swarm optimization (PSO) is proposed. In this approach, the minimization of the deviation between the EVLBL trajectory and the dead reckoning trajectory is set as the optimization objective, and the coordinates of each beacon are iteratively optimized. The simulation results demonstrate that the proposed EVLBL-based PSO algorithm (EVPSO) significantly enhanced the calibration efficiency and positional accuracy of the beacon array. Compared with conventional methods, the estimation error of the beacon positions was reduced from 6.40 m to within 1.00 m. After compensating for the beacon array positions, the positioning error of the LBL system decreased from approximately 5.00 m (with conventional methods) to around 1.00 m (with EVPSO), demonstrating the effectiveness of the proposed approach. Full article
(This article belongs to the Special Issue Navigation and Detection Fusion for Autonomous Underwater Vehicles)
16 pages, 701 KiB  
Systematic Review
Alterations in the Gut Microbiome Composition of People Living with HIV in the Asia–Pacific Region: A Systematic Review
by Paul Benedic U. Salvador, Patrick Josemaria d. R. Altavas, Mark Angelo S. del Rosario, Eric David B. Ornos and Leslie Michelle M. Dalmacio
Clin. Pract. 2024, 14(3), 846-861; https://doi.org/10.3390/clinpract14030066 (registering DOI) - 15 May 2024
Abstract
Human immunodeficiency virus (HIV) infection continues to present a global health issue. Recent studies have explored the potential role of the gut microbiome in HIV infection for novel therapeutic approaches. We investigated the gut microbiome composition of people living with HIV (PLHIV) in [...] Read more.
Human immunodeficiency virus (HIV) infection continues to present a global health issue. Recent studies have explored the potential role of the gut microbiome in HIV infection for novel therapeutic approaches. We investigated the gut microbiome composition of people living with HIV (PLHIV) in the Asia–Pacific region. This review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. An electronic search was conducted in the PubMed/MEDLINE, Scopus, and ScienceDirect databases using keywords such as “HIV”, “PLHIV”, “AIDS”, “gut microbiome”, “gut dysbiosis”, and “metagenomics”. Only peer-reviewed and full-text studies published in English were included. A total of 15 studies from the Asia–Pacific region were included for analysis. Compared to healthy controls, PLHIV showed an increased abundance of Proteobacteria and its genera, which may be considered pathobionts, and decreased abundances of Bacteroidetes and several genera under Firmicutes with known short-chain fatty acid and immunoregulatory activities. Predominant taxa such as Ruminococcaceae and Prevotellaceae were also associated with clinical factors such as CD4 count, the CD4/CD8 ratio, and inflammatory cytokines. This review highlights gut microbiome changes among PLHIV in the Asia–Pacific region, indicating potential bacterial signatures for prognostication. The partial restoration of the microbiome toward beneficial taxa may ensure the long-term success of treatment, promoting immune recovery while maintaining viral load suppression. Full article
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13 pages, 453 KiB  
Communication
Nutritional Challenges in Nursing Homes: Pilot Study on Macronutrient Intake and Status of Vitamins D and B12
by Živa Lavriša and Igor Pravst
Nutrients 2024, 16(10), 1495; https://doi.org/10.3390/nu16101495 (registering DOI) - 15 May 2024
Abstract
Older adults living in nursing homes (NH) are considered a population group that could be at risk in terms of nutrition, even more so than their community-dwelling peers. Evidence on the nutritional status of NH residents is scarce, as they are commonly excluded [...] Read more.
Older adults living in nursing homes (NH) are considered a population group that could be at risk in terms of nutrition, even more so than their community-dwelling peers. Evidence on the nutritional status of NH residents is scarce, as they are commonly excluded from population-based dietary studies. This is also the case in Slovenia. In the presented pilot study, we assessed the intake of macronutrients as well as the intake and status of vitamin D and vitamin B12 on a sample of NH and NH daycare center users to explore the need for a larger representative study. The pilot study included 37 participants from three Slovenian NH (20 participants) and their daycare centers (17 participants). Daycare centers offer daytime care services for older adults, where users are also provided with major meals during their stay. Intakes of energy and nutrients were estimated by three 24 h dietary records. Fasting blood samples were collected for the assessment of vitamin D and vitamin B12 status. Over 90% of the participants had daily energy and protein intakes below recommendations (reference values: energy intake: males 2100 kcal and females 1700 kcal; protein intake > 1 g/kg body mass). The males’ median daily intakes of vitamin D were 1.7 µg (1.5 µg females), and 2.3 µg for vitamin B12 (2.0 µg females). None of the participants had adequate vitamin D intake (>20 µg), and 92.3% males and 87.5% females had inadequate vitamin B12 intake (<4 µg). The prevalence of vitamin D deficiency (serum 25-OH-D conc. < 30 nmol/L) was 100% among NH residents and 53% among NH daycare center users. The prevalence of vitamin B12 deficiency was found in 20% of NH residents. The study results highlighted that certain nutrients might be critical in this population, especially among NH residents; however, a more thorough investigation with the inclusion of other important markers of nutritional status should be performed on a larger, representative sample to support the development and implementation of appropriate public health interventions. Full article
(This article belongs to the Section Geriatric Nutrition)
11 pages, 1912 KiB  
Article
The Generation of Circularly Polarized Isolated Attosecond Pulses with Tunable Helicity from CO Molecules in Polarization Gating Laser Fields
by Shiju Chen, Hua Yuan, Feng Wang, Jiahang Song, Yue Zhao, Chunhui Yang, Tianxin Ou, Ru Zhang, Qiang Chang and Yuping Sun
Photonics 2024, 11(5), 464; https://doi.org/10.3390/photonics11050464 (registering DOI) - 15 May 2024
Abstract
We theoretically demonstrate a scheme to generate circularly polarized (CP) isolated attosecond pulses (IAPs) with tunable helicity using a polarization gating laser field interacting with the CO molecule. The results show that a broadband CP supercontinuum is produced from the oriented CO molecule, [...] Read more.
We theoretically demonstrate a scheme to generate circularly polarized (CP) isolated attosecond pulses (IAPs) with tunable helicity using a polarization gating laser field interacting with the CO molecule. The results show that a broadband CP supercontinuum is produced from the oriented CO molecule, which supports the generation of an IAP with an ellipticity of 0.98 and a duration of 90 as. Furthermore, the helicity of the generated harmonics and IAP can be effectively controlled by modulating the laser field and the orientation angle of the CO molecule. Our method will advance research on chiral-specific dynamics and magnetic circular dichroism on the attosecond timescale. Full article
17 pages, 7183 KiB  
Article
Updates on Impact Ionisation Triggering of Thyristors
by Alicia Ana del Barrio Montañés, Viliam Senaj, Thomas Kramer and Martin Sack
Appl. Sci. 2024, 14(10), 4196; https://doi.org/10.3390/app14104196 (registering DOI) - 15 May 2024
Abstract
High voltage (HV) generators are used in multiple industrial and scientific facilities. Recent publications have demonstrated that triggering industrial thyristors (relatively slow switching devices) in overvoltage mode, also called impact ionization mode, significantly enhances their dU/dt and dI/dt characteristics. This novel triggering methodology [...] Read more.
High voltage (HV) generators are used in multiple industrial and scientific facilities. Recent publications have demonstrated that triggering industrial thyristors (relatively slow switching devices) in overvoltage mode, also called impact ionization mode, significantly enhances their dU/dt and dI/dt characteristics. This novel triggering methodology necessitates the application of substantial overvoltage between the thyristor’s anode and cathode, delivered with a swift slew rate exceeding 1 kV/ns. The adoption of compact pulse generators constructed from commercially available off-the-shelf components (COTS) opens up avenues for deploying this technology across various domains, including the implementation of high-speed kicker generators in particle accelerators. In our methodology, we employed commercially available high-voltage SiC MOSFETs along with a custom-designed fast gate driver. This driver was conceptualized based on the recent development of gate boosting techniques, featuring a driving voltage exceeding 600 V. The gate driver for these MOSFETs comprises three key components: a level-shifter with NMOS and PMOS transistors, a compact Marx generator with two avalanche transistors, and a GaN HEMT in a high input and low output impedance configuration. The proposed gate-boosting driver achieves a slew rate exceeding 1 kV/ns for the driving pulse. Furthermore, we demonstrate that with this driver, a 1.7 kV rated SiC MOSFET can produce an output pulse of 1.45 kV and a maximum slew rate of ≈2.5 kV/ns. This gate-boosting driver aims to minimize commutation times, achieves a slew rate of over 1 kV/ns, and handle higher loads, making it ideal for impact ionization triggering of industrial thyristors. Full article
16 pages, 781 KiB  
Article
Postnatal Brain Trajectories and Maternal Intelligence Predict Childhood Outcomes in Complex CHD
by Vincent K. Lee, Rafael Ceschin, William T. Reynolds, Benjamin Meyers, Julia Wallace, Douglas Landsittel, Heather M. Joseph, Daryaneh Badaly, J. William Gaynor, Daniel Licht, Nathaniel H. Greene, Ken M. Brady, Jill V. Hunter, Zili D. Chu, Elisabeth A. Wilde, R. Blaine Easley, Dean Andropoulos and Ashok Panigrahy
J. Clin. Med. 2024, 13(10), 2922; https://doi.org/10.3390/jcm13102922 (registering DOI) - 15 May 2024
Abstract
Objective: To determine whether early structural brain trajectories predict early childhood neurodevelopmental deficits in complex CHD patients and to assess relative cumulative risk profiles of clinical, genetic, and demographic risk factors across early development. Study Design: Term neonates with complex CHDs were [...] Read more.
Objective: To determine whether early structural brain trajectories predict early childhood neurodevelopmental deficits in complex CHD patients and to assess relative cumulative risk profiles of clinical, genetic, and demographic risk factors across early development. Study Design: Term neonates with complex CHDs were recruited at Texas Children’s Hospital from 2005–2011. Ninety-five participants underwent three structural MRI scans and three neurodevelopmental assessments. Brain region volumes and white matter tract fractional anisotropy and radial diffusivity were used to calculate trajectories: perioperative, postsurgical, and overall. Gross cognitive, language, and visuo-motor outcomes were assessed with the Bayley Scales of Infant and Toddler Development and with the Wechsler Preschool and Primary Scale of Intelligence and Beery–Buktenica Developmental Test of Visual–Motor Integration. Multi-variable models incorporated risk factors. Results: Reduced overall period volumetric trajectories predicted poor language outcomes: brainstem ((β, 95% CI) 0.0977, 0.0382–0.1571; p = 0.0022) and white matter (0.0023, 0.0001–0.0046; p = 0.0397) at 5 years; brainstem (0.0711, 0.0157–0.1265; p = 0.0134) and deep grey matter (0.0085, 0.0011–0.0160; p = 0.0258) at 3 years. Maternal IQ was the strongest contributor to language variance, increasing from 37% at 1 year, 62% at 3 years, and 81% at 5 years. Genetic abnormality’s contribution to variance decreased from 41% at 1 year to 25% at 3 years and was insignificant at 5 years. Conclusion: Reduced postnatal subcortical–cerebral white matter trajectories predicted poor early childhood neurodevelopmental outcomes, despite high contribution of maternal IQ. Maternal IQ was cumulative over time, exceeding the influence of known cardiac and genetic factors in complex CHD, underscoring the importance of heritable and parent-based environmental factors. Full article
(This article belongs to the Section Cardiology)
23 pages, 9844 KiB  
Article
Retinex Jointed Multiscale CLAHE Model for HDR Image Tone Compression
by Yu-Joong Kim, Dong-Min Son and Sung-Hak Lee
Mathematics 2024, 12(10), 1541; https://doi.org/10.3390/math12101541 (registering DOI) - 15 May 2024
Abstract
Tone-mapping algorithms aim to compress a wide dynamic range image into a narrower dynamic range image suitable for display on imaging devices. A representative tone-mapping algorithm, Retinex theory, reflects color constancy based on the human visual system and performs dynamic range compression. However, [...] Read more.
Tone-mapping algorithms aim to compress a wide dynamic range image into a narrower dynamic range image suitable for display on imaging devices. A representative tone-mapping algorithm, Retinex theory, reflects color constancy based on the human visual system and performs dynamic range compression. However, it may induce halo artifacts in some areas or degrade chroma and detail. Thus, this paper proposes a Retinex jointed multiscale contrast limited adaptive histogram equalization method. The proposed algorithm reduces localized halo artifacts and detail loss while maintaining the tone-compression effect via high-scale Retinex processing. A performance comparison of the experimental results between the proposed and existing methods confirms that the proposed method effectively reduces the existing problems and displays better image quality. Full article
(This article belongs to the Special Issue New Advances and Applications in Image Processing and Computer Vision)
42 pages, 6191 KiB  
Review
Communications and Data Science for the Success of Vehicle-to-Grid Technologies: Current State and Future Trends
by Noelia Uribe-Pérez, Amaia Gonzalez-Garrido, Alexander Gallarreta, Daniel Justel, Mikel González-Pérez, Jon González-Ramos, Ane Arrizabalaga, Francisco Javier Asensio and Peru Bidaguren
Electronics 2024, 13(10), 1940; https://doi.org/10.3390/electronics13101940 (registering DOI) - 15 May 2024
Abstract
Vehicle-to-grid (V2G) technology has emerged as a promising solution for enhancing the integration of electric vehicles (EVs) into the electric grid, offering benefits, such as distributed energy resource (DER) integration, grid stability support, and peak demand management, among others, as well as environmental [...] Read more.
Vehicle-to-grid (V2G) technology has emerged as a promising solution for enhancing the integration of electric vehicles (EVs) into the electric grid, offering benefits, such as distributed energy resource (DER) integration, grid stability support, and peak demand management, among others, as well as environmental advantages. This study provides a comprehensive review of V2G systems, with a specific focus on the role of the communication, as they have been identified as key enablers, as well as the challenges that V2G must face. It begins by introducing the fundamentals of V2G systems, including their architecture, operation, and a description of the benefits for different sectors. It then delves into the communication technologies and protocols in V2G systems, highlighting the key requirements in achieving reliable and efficient communication between EVs and the different agents involved. A comprehensive review of communication standards is described, as well as the main communication technologies, which are evaluated in terms of their suitability for V2G applications. Furthermore, the study discusses the challenges and environmental implications of V2G technology, emphasizing the importance of addressing strong and reliable communications to maximize its potential benefits. Finally, future research directions and potential solutions for overcoming challenges in V2G systems are outlined, offering useful insights for researchers, policymakers, and administrations as well as related industry stakeholders. Full article
(This article belongs to the Section Power Electronics)
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32 pages, 6873 KiB  
Review
Role of Epigenetic Modulation in Neurodegenerative Diseases: Implications of Phytochemical Interventions
by Mani Iyer Prasanth, Bhagavathi Sundaram Sivamaruthi, Clerance Su Yee Cheong, Kanika Verma, Tewin Tencomnao, James Michael Brimson and Anchalee Prasansuklab
Antioxidants 2024, 13(5), 606; https://doi.org/10.3390/antiox13050606 (registering DOI) - 15 May 2024
Abstract
Epigenetics defines changes in cell function without involving alterations in DNA sequence. Neuroepigenetics bridges neuroscience and epigenetics by regulating gene expression in the nervous system and its impact on brain function. With the increase in research in recent years, it was observed that [...] Read more.
Epigenetics defines changes in cell function without involving alterations in DNA sequence. Neuroepigenetics bridges neuroscience and epigenetics by regulating gene expression in the nervous system and its impact on brain function. With the increase in research in recent years, it was observed that alterations in the gene expression did not always originate from changes in the genetic sequence, which has led to understanding the role of epigenetics in neurodegenerative diseases (NDDs) including Alzheimer’s disease (AD) and Parkinson’s disease (PD). Epigenetic alterations contribute to the aberrant expression of genes involved in neuroinflammation, protein aggregation, and neuronal death. Natural phytochemicals have shown promise as potential therapeutic agents against NDDs because of their antioxidant, anti-inflammatory, and neuroprotective effects in cellular and animal models. For instance, resveratrol (grapes), curcumin (turmeric), and epigallocatechin gallate (EGCG; green tea) exhibit neuroprotective effects through their influence on DNA methylation patterns, histone acetylation, and non-coding RNA expression profiles. Phytochemicals also aid in slowing disease progression, preserving neuronal function, and enhancing cognitive and motor abilities. The present review focuses on various epigenetic modifications involved in the pathology of NDDs, including AD and PD, gene expression regulation related to epigenetic alterations, and the role of specific polyphenols in influencing epigenetic modifications in AD and PD. Full article
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22 pages, 1640 KiB  
Article
Novel Wide-Working-Temperature NaNO3-KNO3-Na2SO4 Molten Salt for Solar Thermal Energy Storage
by Huaiyou Wang, Jinli Li, Yuan Zhong, Xu Liu and Min Wang
Molecules 2024, 29(10), 2328; https://doi.org/10.3390/molecules29102328 (registering DOI) - 15 May 2024
Abstract
A novel ternary eutectic salt, NaNO3-KNO3-Na2SO4 (TMS), was designed and prepared for thermal energy storage (TES) to address the issues of the narrow temperature range and low specific heat of solar salt molten salt. The thermo-physical [...] Read more.
A novel ternary eutectic salt, NaNO3-KNO3-Na2SO4 (TMS), was designed and prepared for thermal energy storage (TES) to address the issues of the narrow temperature range and low specific heat of solar salt molten salt. The thermo-physical properties of TMS-2, such as melting point, decomposition temperature, fusion enthalpy, density, viscosity, specific heat capacity and volumetric thermal energy storage capacity (ETES), were determined. Furthermore, a comparison of the thermo-physical properties between commercial solar salt and TMS-2 was carried out. TMS-2 had a melting point 6.5 °C lower and a decomposition temperature 38.93 °C higher than those of solar salt. The use temperature range of TMS molten salt was 45.43 °C larger than that of solar salt, which had been widened about 13.17%. Within the testing temperature range, the average specific heat capacity of TMS-2 (1.69 J·K−1·g−1) was 9.03% higher than that of solar salt (1.55 J·K−1·g−1). TMS-2 also showed higher density, slightly higher viscosity and higher ETES. XRD, FTIR and Raman spectra SEM showed that the composition and structure of the synthesized new molten salt were different, which explained the specific heat capacity increasing. Molecular dynamic (MD) simulation was performed to explore the different macroscopic properties of solar salt and TMS at the molecular level. The MD simulation results suggested that cation–cation and cation–anion interactions became weaker as the temperature increased and the randomness of molecular motion increased, which revealed that the interaction between the cation cluster and anion cluster became loose. The stronger interaction between Na-SO4 cation–anion clusters indicated that TMS-2 molten salt had a higher specific heat capacity than solar salt. The result of the thermal stability analysis indicated that the weight losses of solar salt and TMS-2 at 550 °C were only 27% and 53%, respectively. Both the simulation and experimental study indicated that TMS-2 is a promising candidate fluid for solar power generation systems. Full article
17 pages, 11881 KiB  
Article
Microstructure-Based Modeling of Deformation and Damage Behavior of Extruded and Additively Manufactured 316L Stainless Steels
by Huai Wang, Ho-Won Lee, Minh Tien Tran and Dong-Kyu Kim
Materials 2024, 17(10), 2360; https://doi.org/10.3390/ma17102360 (registering DOI) - 15 May 2024
Abstract
In this study, we investigated the micromechanical deformation and damage behavior of commercially extruded and additively manufactured 316L stainless steels (AMed SS316L) by combining experimental examinations and crystal plasticity modeling. The AMed alloy was fabricated using the laser powder bed fusion (LPBF) technique [...] Read more.
In this study, we investigated the micromechanical deformation and damage behavior of commercially extruded and additively manufactured 316L stainless steels (AMed SS316L) by combining experimental examinations and crystal plasticity modeling. The AMed alloy was fabricated using the laser powder bed fusion (LPBF) technique with an orthogonal scanning strategy to control the directionality of the as-fabricated material. Optical microscopy and electron backscatter diffraction measurements revealed distinct grain morphologies and crystallographic textures in the two alloys. Uniaxial tensile test results suggested that the LPBFed alloy exhibited an increased yield strength, reduced elongation, and comparable ultimate tensile strength in comparison to those of the extruded alloy. A microstructure-based crystal plasticity model was developed to simulate the micromechanical deformation behavior of the alloys using representative volume elements based on realistic microstructures. A ductile fracture criterion based on the microscopically dissipated plastic energy on a slip system was adopted to predict the microscopic damage accumulation of the alloys during plastic deformation. The developed model could accurately predict the stress–strain behavior and evolution of the crystallographic textures in both the alloys. We reveal that the increased yield strength in the LPBFed alloy, compared to that in the extruded alloy, is attributed to the higher as-manufactured dislocation density and the cellular subgrain structure, resulting in a reduced elongation. The presence of annealing twins and favorable texture in the extruded alloy contributed to its excellent elongation, along with a higher hardening rate owing to twin–dislocation interactions during plastic deformation. Moreover, the grain morphology and defect state (e.g., dislocations and twins) in the initial state can significantly affect strain localization and damage accumulation in alloys. Full article
(This article belongs to the Topic Advances in Computational Materials Sciences)
23 pages, 2100 KiB  
Article
Solvothermally Grown Oriented WO3 Nanoflakes for the Photocatalytic Degradation of Pharmaceuticals in a Flow Reactor
by Mirco Cescon, Claudia Stevanin, Matteo Ardit, Michele Orlandi, Annalisa Martucci, Tatiana Chenet, Luisa Pasti, Stefano Caramori and Vito Cristino
Nanomaterials 2024, 14(10), 860; https://doi.org/10.3390/nano14100860 (registering DOI) - 15 May 2024
Abstract
Contamination by pharmaceuticals adversely affects the quality of natural water, causing environmental and health concerns. In this study, target drugs (oxazepam, OZ, 17-α-ethinylestradiol, EE2, and drospirenone, DRO), which have been extensively detected in the effluents of WWTPs over the past decades, were selected. [...] Read more.
Contamination by pharmaceuticals adversely affects the quality of natural water, causing environmental and health concerns. In this study, target drugs (oxazepam, OZ, 17-α-ethinylestradiol, EE2, and drospirenone, DRO), which have been extensively detected in the effluents of WWTPs over the past decades, were selected. We report here a new photoactive system, operating under visible light, capable of degrading EE2, OZ and DRO in water. The photocatalytic system comprised glass spheres coated with nanostructured, solvothermally treated WO3 that improves the ease of handling of the photocatalyst and allows for the implementation of a continuous flow process. The photocatalytic system based on solvothermal WO3 shows much better results in terms of photocurrent generation and photocatalyst stability with respect to state-of-the-art WO3 nanoparticles. Results herein obtained demonstrate that the proposed flow system is a promising prototype for enhanced contaminant degradation exploiting advanced oxidation processes. Full article
(This article belongs to the Special Issue Advanced Nanomaterials for Water Remediation (2nd Edition))
36 pages, 834 KiB  
Article
Enhancing Dementia Nursing Homes in South Korea: Lessons from German Building Standards
by Soo In Jee
Buildings 2024, 14(5), 1427; https://doi.org/10.3390/buildings14051427 (registering DOI) - 15 May 2024
Abstract
South Korea is an aging society with a rapidly increasing number of people with dementia. In that context, this study aimed to compare dementia nursing home building standards in South Korea and Germany, based on the minimum physical and architectural requirements specified by [...] Read more.
South Korea is an aging society with a rapidly increasing number of people with dementia. In that context, this study aimed to compare dementia nursing home building standards in South Korea and Germany, based on the minimum physical and architectural requirements specified by both countries’ relevant laws, to gain insights into improving South Korean building standards. I examined South Korea’s Welfare of Senior Citizens Act and its Enforcement Regulations, and Germany’s Federal Nursing Home Act (HeimG), Regulation on Minimum Standards for Nursing Homes (HeimMindBauV), and the corresponding state regulations. The analysis revealed differences regarding the basic requirements, facility sizes, composition of necessary rooms, and detailed regulations pertaining to these rooms. South Korea emphasized autonomy, including barrier-free and compensatory environments, as well as safety and security. Meanwhile, Germany enhanced similar aspects of autonomy to those in South Korea, including the barrier-free standard DIN 18040-2. Additionally, Germany incorporated features such as familiarity, sensory stimulation, legibility, and social interaction, reflecting aspects that offer orientational cues for autonomy. Improving South Korean building standards requires stronger regulations on the autonomy of individuals with dementia. Further, additional regulations on familiarity, sensory stimulation, legibility, and social interactions should be considered. The results provide foundational data for cross-national comparisons to establish building standards for dementia-friendly built spaces in dementia nursing homes in South Korea. Further surveys on spatial utilization, discussions, and the application of proposed improvements in Korea would contribute to enhancing the dementia-friendly nursing home design in the country. Full article
(This article belongs to the Special Issue Advances of Healthy Environment Design in Urban Development)
14 pages, 424 KiB  
Article
Deep Learning-Driven Interference Perceptual Multi-Modulation for Full-Duplex Systems
by Taehyoung Kim and Gyuyeol Kong
Mathematics 2024, 12(10), 1542; https://doi.org/10.3390/math12101542 (registering DOI) - 15 May 2024
Abstract
In this paper, a novel data transmission scheme, interference perceptual multi-modulation (IP-MM), is proposed for full-duplex (FD) systems. In order to unlink the conventional uplink (UL) data transmission using a single modulation and coding scheme (MCS) over the entire assigned UL bandwidth, IP-MM [...] Read more.
In this paper, a novel data transmission scheme, interference perceptual multi-modulation (IP-MM), is proposed for full-duplex (FD) systems. In order to unlink the conventional uplink (UL) data transmission using a single modulation and coding scheme (MCS) over the entire assigned UL bandwidth, IP-MM enables the transmission of UL data channels based on multiple MCS levels, where a different MCS level is applied to each subband of UL transmission. In IP-MM, a deep convolutional neural network is used for MCS-level prediction for each UL subband by estimating the potential residual self-interference (SI) according to the downlink (DL) resource allocation pattern. In addition, a subband-based UL transmission procedure is introduced from a specification point of view to enable IP-MM-based UL transmission. The benefits of IP-MM are verified using simulations, and it is observed that IP-MM achieves approximately 20% throughput gain compared to the conventional UL transmission scheme. Full article
15 pages, 690 KiB  
Article
Optimization of Renewable Energy Hydrogen Production Systems Using Volatility Improved Multi-Objective Particle Swarm Algorithm
by Hui Wang, Xiaowen Chen, Qianpeng Yang, Bowen Li, Zongyu Yue, Jeffrey Dankwa Ampah, Haifeng Liu and Mingfa Yao
Energies 2024, 17(10), 2384; https://doi.org/10.3390/en17102384 (registering DOI) - 15 May 2024
Abstract
Optimizing the energy structure to effectively enhance the integration level of renewable energy is an important pathway for achieving dual carbon goals. This study utilizes an improved multi-objective particle swarm optimization algorithm based on load fluctuation rates to optimize the architecture and unit [...] Read more.
Optimizing the energy structure to effectively enhance the integration level of renewable energy is an important pathway for achieving dual carbon goals. This study utilizes an improved multi-objective particle swarm optimization algorithm based on load fluctuation rates to optimize the architecture and unit capacity of hydrogen production systems. It investigates the optimal configuration methods for the architectural model of new energy hydrogen production systems in Xining City, Qinghai Province, as well as the internal storage battery, ALK hydrogen production equipment, and PEM hydrogen production equipment, aiming at various scenarios of power sources such as wind, solar, wind–solar complementary, and wind–solar–storage complementary, as well as intermittent hydrogen production scenarios such as hydrogen stations, hydrogen metallurgy, and continuous hydrogen production scenarios such as hydrogen methanol production. The results indicate that the fluctuation of hydrogen load scenarios has a significant impact on the installed capacity and initial investment of the system. Compared with the single-channel photovoltaic hydrogen production scheme, the dual-channel hydrogen production scheme still reduces equipment capacity by 6.04% and initial investment by 6.16% in the chemical hydrogen scenario with the least load fluctuation. Full article
(This article belongs to the Section B: Energy and Environment)
20 pages, 964 KiB  
Review
Progress of Antimicrobial Mechanisms of Stilbenoids
by Xiancai Li, Yongqing Li, Binghong Xiong and Shengxiang Qiu
Pharmaceutics 2024, 16(5), 663; https://doi.org/10.3390/pharmaceutics16050663 (registering DOI) - 15 May 2024
Abstract
Antimicrobial drugs have made outstanding contributions to the treatment of pathogenic infections. However, the emergence of drug resistance continues to be a major threat to human health in recent years, and therefore, the search for novel antimicrobial drugs is particularly urgent. With a [...] Read more.
Antimicrobial drugs have made outstanding contributions to the treatment of pathogenic infections. However, the emergence of drug resistance continues to be a major threat to human health in recent years, and therefore, the search for novel antimicrobial drugs is particularly urgent. With a deeper understanding of microbial habits and drug resistance mechanisms, various creative strategies for the development of novel antibiotics have been proposed. Stilbenoids, characterized by a C6–C2–C6 carbon skeleton, have recently been widely recognized for their flexible antimicrobial roles. Here, we comprehensively summarize the mode of action of stilbenoids from the viewpoint of their direct antimicrobial properties, antibiofilm and antivirulence activities and their role in reversing drug resistance. This review will provide an important reference for the future development and research into the mechanisms of stilbenoids as antimicrobial agents. Full article
(This article belongs to the Topic Challenges and Future Prospects of Antibacterial Therapy)
12 pages, 29069 KiB  
Article
Zr as an Alternative Grain Refiner in the Novel AlSi5Cu2Mg Alloy
by Dana Bolibruchová, Marek Matejka, Lukáš Širanec and Martin Švec
Metals 2024, 14(5), 581; https://doi.org/10.3390/met14050581 (registering DOI) - 15 May 2024
Abstract
Al-Si-Cu-Mg alloys are among the most significant types of aluminum alloys, accounting for 85–90% of all castings used in the automotive sector. These alloys are used, for example, in the manufacturing of engine blocks and cylinder heads due to their excellent specific strength [...] Read more.
Al-Si-Cu-Mg alloys are among the most significant types of aluminum alloys, accounting for 85–90% of all castings used in the automotive sector. These alloys are used, for example, in the manufacturing of engine blocks and cylinder heads due to their excellent specific strength (ratio of strength to specific weight) and superior castability and thermal conductivity. This study investigated the effect of using Zr as an alternative grain refiner in the novel AlSi5Cu2Mg cylinder head alloy. The microstructure of this alloy could not be refined via common Al-Ti-B grain refiners due to its specifically designed chemical composition, which limits the maximum Ti content to 0.03 wt.%. The results showed that the addition of Zr via the AlZr20 master alloy led to a gradual increase in the solidus temperature and to the grain refinement of the microstructure with the addition of as little as 0.05 wt.% Zr. The addition of more Zr (0.10, 0.15, and 0.20 wt.%) led to a gradual grain refinement effect for the alloy. The presence of Zr in the AlSi5Cu2Mg alloy was reflected in the formation of Zr-rich intermetallic phases with acicular morphology. Such phases acted as potent nucleants for the α-Al grain. Full article
(This article belongs to the Special Issue Grain Refinement and Mechanical Properties of Cast Alloys)
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13 pages, 3978 KiB  
Article
Hydrogen Safety by Design: Exclusion of Flame Blow-Out from a TPRD
by Mina Kazemi, Sile Brennan and Vladimir Molkov
Hydrogen 2024, 5(2), 280-292; https://doi.org/10.3390/hydrogen5020016 (registering DOI) - 15 May 2024
Abstract
Onboard hydrogen storage tanks are currently fitted with thermally activated pressure relief devices (TPRDs), enabling hydrogen to blowdown in the event of fire. For release diameters below the critical diameter, the flame from the TPRD may blow-out during a pressure drop. Flame blow-outs [...] Read more.
Onboard hydrogen storage tanks are currently fitted with thermally activated pressure relief devices (TPRDs), enabling hydrogen to blowdown in the event of fire. For release diameters below the critical diameter, the flame from the TPRD may blow-out during a pressure drop. Flame blow-outs pose a safety concern for an indoor or covered environment, e.g., a garage or carpark, where hydrogen can accumulate and deflagrate. This study describes the application of a validated computational fluid dynamics (CFD) model to simulate the dynamic flame behaviour from a TPRD designed to exclude its blow-out. The dynamic behaviour replicates a real scenario. Flame behaviour during tank blowdown through two TPRDs with different nozzle geometries is presented. Simulations confirm flame blow-out for a single-diameter TPRD of 0.5 mm during tank blowdown, while the double-diameter nozzle successfully excludes flame blow-out. The pressure at which the flame blow-out process is initiated during blowdown through a single-diameter nozzle was predicted. Full article
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21 pages, 10528 KiB  
Article
Ozone-Assisted Hydrothermal Synthesis Method of Sb-Doped SnO2 Conductive Nanoparticles for Carbon-Free Oxygen-Reduction-Reaction Catalysts of Proton-Exchange-Membrane Hydrogen Fuel Cells
by Takeshi Fukuda, Kenji Iimura, Takanori Yamamoto, Ryuki Tsuji, Maito Tanabe, Seiji Nakashima, Naoki Fukumuro and Seigo Ito
Crystals 2024, 14(5), 462; https://doi.org/10.3390/cryst14050462 (registering DOI) - 15 May 2024
Abstract
Proton-exchange-membrane hydrogen fuel cells (PEMFCs) are an important energy device for achieving a sustainable hydrogen society. Carbon-based catalysts used in PEMFCs’ cathode can degrade significantly during operation-voltage shifts due to the carbon deterioration. The longer lifetime of the system is necessary for the [...] Read more.
Proton-exchange-membrane hydrogen fuel cells (PEMFCs) are an important energy device for achieving a sustainable hydrogen society. Carbon-based catalysts used in PEMFCs’ cathode can degrade significantly during operation-voltage shifts due to the carbon deterioration. The longer lifetime of the system is necessary for the further wide commercialization of PEMFCs. Therefore, carbon-free catalysts are required for PEMFCs. In this study, highly crystallized conducting Sb-doped SnO2 (Sb-SnO2) nanoparticles (smaller than 7 nm in size) were synthesized using an ozone-assisted hydrothermal synthesis. Pt nanoparticles were loaded on Sb-SnO2 supporting particles by polyol method to be “Pt/Sb-SnO2 catalyst”. The Pt/Sb-SnO2 catalyst showed a high oxygen reduction reaction (ORR) mass activity (178.3 A g−1-Pt @ 0.9 V), compared to Pt/C (149.3 A g−1-Pt @ 0.9 V). In addition, the retention ratio from the initial value of electrochemical surface area (ECSA) during 100,000-voltage cycles tests between 1.0 V and 1.5 V, Pt/SnO2 and Pt/Sb-SnO2 catalyst exhibited higher stability (90% and 80%), respectively, than that of Pt/C catalyst (47%). Therefore, the SnO2 and Sb-SnO2 nanoparticles synthesized using this new ozone-assisted hydrothermal method are promising as carbon-free catalyst supports for PEMFCs. Full article
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23 pages, 4458 KiB  
Article
Optimization Design of Straw-Crushing Residual Film Recycling Machine Frame Based on Sensitivity and Grey Correlation Degree
by Pengda Zhao, Hailiang Lyu, Lei Wang, Hongwen Zhang, Zhantao Li, Kunyu Li, Chao Xing and Bocheng Guoyao
Agriculture 2024, 14(5), 764; https://doi.org/10.3390/agriculture14050764 (registering DOI) - 15 May 2024
Abstract
This paper takes the frame as the research object and explores the vibration characteristics of the frame to address the vibration problem of a 1-MSD straw-crushing and residual film recycling machine in the field operation process, and an accurate identification of the modal [...] Read more.
This paper takes the frame as the research object and explores the vibration characteristics of the frame to address the vibration problem of a 1-MSD straw-crushing and residual film recycling machine in the field operation process, and an accurate identification of the modal parameters of the frame is carried out to solve the resonance problem of the machine, which can achieve cost reduction and increase income to a certain extent. The first six natural frequencies of the frame are extracted by finite element modal identification and modal tests, respectively. The rationality of the modal test results is verified using the comprehensive modal and frequency response confidences. The maximum frequency error of modal frequency results of the two methods is only 6.61%, which provides a theoretical basis for the optimal design of the frame. In order to further analyze the resonance problem of the machine, the external excitation frequency of the machine during normal operation in the field is solved and compared with the first six natural frequencies of the frame. The results show that the first natural frequency of the frame (18.89 Hz) is close to the external excitation generated by the stripping roller (16.67 Hz). The first natural frequency and the volume of the frame are set as the optimization objectives, and the optimal optimization scheme is obtained by using the Optistruct solver, sensitivity method, and grey correlation method. The results indicate the first-order natural frequency of the optimized frame is 21.89 Hz, an increase of 15.882%, which is much higher than the excitation frequency of 16.67 Hz, and resonance can be avoided. The corresponding frame volume is 9.975 × 107 mm3, and the volume reduction is 3.46%; the optimized frame has good dynamic performance, which avoids the resonance of the machine and conforms to the lightweight design criteria of agricultural machinery structures. The research results can provide some theoretical reference for this kind of machine in solving the resonance problem and carrying out related vibration characteristics research. Full article
(This article belongs to the Section Agricultural Technology)

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