Search Results (3,360)

The present article relates to the description of phenomenological relations of amorphous material behavior within the framework of viscoelasticity and elastic-viscoplasticity theory, as well as to the creation of its digital analog. Ultra-high-molecular-weight polyethylene (UHMWPE) is considered in the study. The model is based on the results of a series of experimental studies. Free compression of cylindrical specimens in a wide range of temperatures [−40; +80] °C and strain rates [0.1; 4] mm/min was performed. Cylindrical specimens were also used to determine the thermal expansion coefficient of the material. Dynamic mechanical analysis (DMA) was performed on rectangular specimens using a three-point bending configuration. Maxwell and Anand models were used to describe the material behavior. In the framework of the study, the temperature dependence of a number of parameters was established. This influenced the mathematical formulation of the Anand model, which was adapted by introducing the temperature dependence of the activation energy, the initial deformation resistance, and the strain rate sensitivity coefficient. Testing of the material models was carried out in the process of analyzing the deformation of a spherical bridge bearing with a multi-cycle periodic load. The load corresponded to the movement of a train on a bridge structure, without taking into account vibrations. It is shown that the viscoelastic model does not describe the behavior of the material accurately enough for a quantitative analysis of the stress–strain state of the structure. It is necessary to move on to more complex models of material behavior to minimize the discrepancy between the digital analog and the real structure; it has been established that taking into account plastic deformation while describing UHMWPE would allow this to be performed. Full article

Background/Objectives: Workplace violence (WV) against healthcare workers (HCWs) is a major hazard all over the world. Prevention requires a reliable risk assessment. The rate of HCWs reporting a violent event varies considerably across multi-year retrospective studies compared to periodic surveys. We conducted a rapid observational study to demonstrate that data collection methods are more important than socio-cultural and healthcare organizational differences in determining the frequency of reported violence. Methods: In June 2025, in a cross-sectional observational comparison, we examined a total of 236 nurses divided into three groups: the first two were recruited online from Brescia (Italy) and Trollhättan (Sweden), while the third group was composed of Latium (Italy) nurses participating in a sleep health promotion program who answered the same questions on WV online. All the workers reported the frequency of violent incidents experienced in the previous 12 months using the Violent Incident Form (VIF), occupational stress using the Effort/Reward Imbalance questionnaire (ERI), and work ability via the Work Ability Score (WAS). Results: In the three samples, WV was correlated positively with stress and inversely with work ability (p < 0.01), while no significant difference was found between Italian and Swedish nurses in relation to the spot surveys. The nurses questioned directly about WV were significantly younger and reported significantly higher rates of physical aggression (28% vs. 5%, p < 0.001) and all forms of violence (73% vs. 20%, p < 0.001) than those questioned indirectly during the census of all the HCWs. In a multivariate linear regression model, the WV experienced and poor work ability were highly significant predictors of work-related stress (p < 0.001). Nurses who had experienced WV in the previous year had an increased odds ratio (OR = 8.94; Confidence Interval 95% = 4.43; 18.01) of reporting a state of distress. Conclusions: Experience has shown that specific questioning about violence—the commonest method used—encourages respondents to report violent events and may induce overreporting. This method also tends to involve younger workers who are more exposed to WV. On the other hand, prospective studies based on official reports may be influenced by underreporting. Monitoring WV during health promotion interventions included in occupational health surveillance could minimize both phenomena. Systematic studies and meta-analyses which rely mainly on “ad hoc” studies may be biased. Full article

Potato (Solanum tuberosum) is an important crop globally, being a starchy, energy-dense food source rich in several micronutrients and bioactive compounds. Achieving food security for everyone is highly challenging in the context of growing populations and climate change. As a highly adaptable crop, potatoes can significantly contribute to food security for vulnerable populations and have outstanding commercial relevance. Specific pre- and post-harvest parameters influence potato quality. It is vital to understand how these factors interact to shape potato quality, minimizing post-harvest losses, ensuring consumer safety, and enhancing marketability. This review highlights how pre-harvest (cultivation approaches, agronomic conditions, biotic and abiotic stresses) and post-harvest factors impact tuber’s microbial stability, physiological behaviour, nutritional, functional attributes and frying quality. Quality parameters, such as moisture content, dry matter, starch, sugar, protein, antioxidants, and color, are typically measured using both traditional and modern assessment methods. However, advanced non-destructive techniques, such as imaging and spectroscopy, enable rapid, high-throughput quality inspection from the field to storage. This review integrates recent advancements and specific findings to identify factors that contribute to substantial quality degradation or enhancement, as well as current challenges. It also examines how pre- and post-harvest factors collectively impact potato quality. It proposes future directions for quality maintenance and enhancement across the field and storage, highlighting research gaps in the pre- and post-harvest linkage. Full article

The increasing penetration of electric vehicle (EV) fast-charging stations (FCSs) into distribution networks and microgrids poses considerable operational challenges, including voltage deviations, increased power losses, and peak load stress. This work proposes a novel hybrid optimization framework that integrates Lagrangian relaxation (LR) with adaptive sheep flock optimization (ASFO) to address the resource scheduling issues when EVs are penetrated and their impact on net load demand, total cost. Besides the impact of EV uncertainty on energy exchange cost and operational costs, voltage profile deviations were also studied. LR is employed to decompose the original problem and manage complex operational constraints, while ASFO is employed to solve the relaxed subproblems by efficiently exploring the high-dimensional, non-convex solution space. The proposed method is tested on an IEEE 33-bus distribution system with integrated PV and BESS under 24 h dynamic load and renewable scenarios. Results establish that the hybrid LR-ASFO method significantly outperforms conventional methods. Compared to standalone metaheuristics, the proposed framework reduces total cost by 5.6%, improves voltage profile deviations by 2.4%, and minimizes total operational cost by 4.3%. Furthermore, it safeguards constraint feasibility while avoiding premature convergence, thereby accomplishing better global optimality and system reliability. Full article

Schwanniomyces etchellsii is an unconventional, halotolerant microorganism. Like some other yeasts, it can efficiently perform various biocatalytic transformations of organic compounds in seawater more effectively than in freshwater. In seawater, conversion rates are higher, by-product production is minimized, greater substrate loading is possible, and cells can be recycled for further use. To identify the molecular features that explain this behavior, comparative proteomic and lipidomic studies were conducted on cells grown in seawater and freshwater at various growth stages. The results showed higher expression of proteins involved in the stress response, such as glycerol-3-phosphate dehydrogenase, the glycerol transporter Stl1 and the P-type ATPase sodium pump Ena1, and several phospholipid biosynthesis proteins, including inositol-3-phosphate synthase and phosphatidate cytidylyltransferase, in seawater. Changes in metabolic enzymes and other proteins involved in responding to stimuli were also observed between the two conditions. Overall, cells grown in a freshwater medium exhibited higher levels of enzymes involved in biosynthetic processes. Differences in lipid profiles were also observed between cells grown in the two media. Higher levels of monoacyl and diacylglycerols were found in seawater, while higher levels of phospholipids containing serine and ethanolamine were found in freshwater. Consistent with more permeable membranes, cells grown in seawater exhibited lower levels of ergosterol. Full article

Seed germination and early growth in rice are critical stages influenced by the hormonal balance between gibberellins (GA) and abscisic acid (ABA), particularly under low-temperature stress. This study investigated the effects of GA₃ and ABA on seed germination, embryonic growth, gene expression, and biochemical activities in rice cultivars with contrasting tolerance to low temperatures. GA₃ markedly improved germination in resistant cultivars Nagdong and CNDH77, whereas susceptible cultivars showed minimal improvement, while ABA strongly inhibited germination, especially under higher concentrations. GA₃ also promoted embryonic growth, with resistant cultivars displaying the longest embryo cells (10.10 µm and 13.49 µm, respectively), whereas ABA suppressed embryonic growth and completely inhibited germination in susceptible cultivars. Upregulation of GA biosynthesis (OsCPS1 and OsKS1) and signaling genes (OsGID1 and OsGID2) in resistant cultivars correlated with enhanced germination and growth, whereas ABA-induced ABI5 expression suppressed germination, particularly in susceptible cultivars. Hormone quantification confirmed increased endogenous GA₃ after GA₃ treatment and reduced ABA levels under ABA treatment. Additionally, GA₃ modulated ABA signaling genes, upregulating OSK3, ABI3, ABI4, and ABI5, while ABA treatment had contrasting effects, particularly between resistant and susceptible cultivars. GA₃ treatment also enhanced the expression of GA biosynthesis and signaling genes (OsCPS1, OsKS1, OsGID1, and OsGID2), whereas ABA treatment upregulated ABA catabolic genes (OsABA8ox2). GA₃ also enhanced amylase activity and sugar-related gene expression, supporting its role in energy mobilization during germination. Conversely, ABA suppressed cell elongation, reducing it to 4.45 µm in CNDH77 under 100 µM ABA. These findings provide valuable insights into the hormonal regulation of rice seed germination and growth under low-temperature stress, offering potential strategies to enhance seed vigor and stress tolerance in rice breeding. Full article

State-of-charge (SoC) balancing across multiple battery energy storage systems (BESS) is a central challenge in renewable-rich mini-grids. Heterogeneous battery capacities, differing states of health, stochastic renewable generation, and variable loads create a high-dimensional uncertain control problem. Conventional droop-based SoC balancing strategies are decentralized and computationally light but fundamentally reactive and limited, whereas model predictive control (MPC) is insightful but computationally intensive and prone to modeling errors. This paper proposes a Hierarchical Predictive–Adaptive Control (HPAC) framework for SoC balancing in mini-grids using deep reinforcement learning. The framework consists of two synergistic layers operating on different time scales. A long-horizon Predictive Engine, implemented as a federated Transformer network, provides multi-horizon probabilistic forecasts of net load, enabling multiple mini-grids to collaboratively train a high-capacity model without sharing raw data. A fast-timescale Adaptive Controller, implemented as a Soft Actor-Critic (SAC) agent, uses these forecasts to make real-time charge/discharge decisions for each BESS unit. The forecasts are used both to augment the agent’s state representation and to dynamically shape a multi-objective reward function that balances SoC, economic performance, degradation-aware operation, and voltage stability. The paper formulates SoC balancing as a Markov decision process, details the SAC-based control architecture, and presents a comprehensive evaluation using a MATLAB-(R2025a)-based digital-twin simulation environment. A rigorous benchmarking study compares HPAC against fourteen representative controllers spanning rule-based, MPC, and various DRL paradigms. Sensitivity analysis on reward weight selection and ablation studies isolating the contributions of forecasting and dynamic reward shaping are conducted. Stress-test scenarios, including high-volatility net-load conditions and communication impairments, demonstrate the robustness of the approach. Results show that HPAC achieves near-minimal operating cost with essentially zero SoC variance and the lowest voltage variance among all compared controllers, while maintaining moderate energy throughput that implicitly preserves battery lifetime. Finally, the paper discusses a pathway from simulation to hardware-in-the-loop testing and a cloud-edge deployment architecture for practical, real-time deployment in real-world mini-grids. Full article

Globally, lakes are increasingly recognized as sensitive indicators of climate change and ecosystem stress. Qaraoun Lake, Lebanon’s largest artificial reservoir, is a critical resource for irrigation, hydropower generation, and domestic water supply. Over the past 25 years, satellite remote sensing has enabled consistent monitoring of its hydrological and environmental dynamics. This study leverages the advanced cloud-based processing capabilities of Google Earth Engine (GEE) to analyze over 180 cloud-free scenes from Landsat 7 (Enhanced Thematic Mapper Plus) (ETM+) from 2000 to present, Landsat 8 Operational Land Imager and Thermal Infrared Sensor (OLI/TIRS) from 2013 to present, and Landsat 9 OLI-2/TIRS-2 from 2021 to present, quantifying changes in lake surface area, water volume, and pollution levels. Water extent was delineated using the Modified Normalized Difference Water Index (MNDWI), enhanced through pansharpening to improve spatial resolution from 30 m to 15 m. Water quality was evaluated using a composite pollution index that integrates three spectral indicators—the Normalized Difference Chlorophyll Index (NDCI), the Floating Algae Index (FAI), and a normalized Shortwave Infrared (SWIR) band—which serves as a proxy for turbidity and organic matter. This index was further standardized against a conservative Normalized Difference Vegetation Index (NDVI) threshold to reduce vegetation interference. The resulting index ranges from near-zero (minimal pollution) to values exceeding 1.0 (severe pollution), with higher values indicating elevated chlorophyll concentrations, surface reflectance anomalies, and suspended particulate matter. Results indicate a significant decline in mean annual water volume, from a peak of 174.07 million m³ in 2003 to a low of 106.62 million m³ in 2025 (until mid-November). Concurrently, pollution levels increased markedly, with the average index rising from 0.0028 in 2000 to a peak of 0.2465 in 2024. Episodic spikes exceeding 1.0 were detected in 2005, 2016, and 2024, corresponding to documented contamination events. These findings were validated against multiple institutional and international reports, confirming the reliability and efficiency of the GEE-based methodology. Time-series visualizations generated through GEE underscore a dual deterioration, both hydrological and qualitative, highlighting the lake’s growing vulnerability to anthropogenic pressures and climate variability. The study emphasizes the urgent need for integrated watershed management, pollution control measures, and long-term environmental monitoring to safeguard Lebanon’s water security and ecological resilience. Full article

Stapedotomy is performed to restore ossicular chain sound transmission by inserting a piston prosthesis that couples the long process of the incus to the oval window, thereby addressing conductive hearing loss associated with otosclerosis. This study investigates the effects of crimping force, prosthesis material, and loop geometry on incus to optimize fixation while minimizing complications such as incudal necrosis. Finite element analyses were performed to quantify interface pressures and von Mises stresses for titanium prostheses with loop-band widths of 0.2, 0.3, and 0.5 mm under crimping forces of 300–500 mN and for polytetrafluoroethylene (PTFE) prostheses with loop outer diameters (OD) of 1.2, 1.4, and 1.8 mm. The analysis results showed that PTFE prostheses generated significantly lower interface pressures and stress compared to titanium. For PTFE prostheses, the equivalent von Mises stresses remained well below the critical threshold, with values ranging from 3.5 MPa up to peaks of approximately 43 MPa depending on the loop’s outer diameter. In contrast, titanium prostheses exhibited a marked dependency on crimping force and band width. At a force of 300 mN, stresses were modest (approximately 16–24 MPa). However, when increasing the force to 400 mN, stresses approached the critical threshold (up to approximately 53 MPa). With crimping forces of 500 mN, especially with band widths greater than 0.3 mm, stresses exceeded the cortical bone strength threshold (approximately 61–64 MPa), indicating an increased risk of mechanical overload and potential incudal necrosis. These findings highlight the importance, in a clinical context, of controlling the crimping force and selecting the material and geometry of the prosthesis to achieve secure coupling while preserving the incus’s structural integrity. Full article

Injectable hydrogels (IHs) have gained considerable interest in biomedical and aesthetic applications due to their minimally invasive delivery, selective localization, and sustained release of bioactive agents. They exhibit flowability during administration and undergo in situ gelation under physiological conditions. These behaviors are influenced by their tunable structural, physical, mechanical, and viscoelastic properties, modulating performance. Rheological parameters, including viscosity (η), storage modulus (G′), loss modulus (G″), and yield stress (τ_y) of IHs with time (t), shear rate ($\stackrel{·}{\gamma }$), and frequency (f), explaining their shear thinning, thixotropy, viscoelasticity, and gelatin kinetics, serve as key quantitative indicators of their injectability, self-healing capability, and structural and mechanical stability. The rheological characteristics reflect molecular interactions and crosslinking mechanisms within IH networks, thereby linking formulation to provide overall performance, including injectability, biodegradability, and controlled release. This review summarizes recent advances in IHs for diverse applications, with a primary focus on their rheological properties. It also briefly addresses their composition, intermolecular interactions, and correlated function and performance. The applications discussed include hemostatic and wound dressings, tissue engineering and regenerative medicine scaffolds, drug delivery systems, reconstructive and aesthetic materials, and functional bioinks for 3D printing. Overall, this review demonstrates that rheological characterization provides an essential framework for the rational engineering of next-generation IH systems. Full article

The 5083 aluminum alloy is widely used in marine engineering due to its excellent corrosion resistance and weldability. To address microstructural defects that may arise during hot rolling, homogenization annealing is employed as a critical post-processing step to enhance mechanical and processing properties. This study systematically investigates the effects of different homogenization annealing temperatures (held for 1 h) on the microstructure, corrosion behavior, and mechanical properties of hot-rolled 5083 aluminum alloy. The microstructural characteristics, phase composition, and corrosion morphology were characterized using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), polarized light microscopy (POM), electron backscatter diffraction (EBSD), and electrochemical tests. Microhardness was measured using a Vickers hardness tester. The results indicate that the annealing temperature markedly influences the type, morphology, and distribution of precipitated secondary phases and significantly affects grain refinement. The alloy treated at 350 °C (5083–350 °C) exhibited optimal corrosion resistance, as evidenced by electrochemical impedance spectroscopy showing the highest charge transfer resistance and surface morphology analysis revealing minimal and shallow corrosion pits. Simultaneously, this treatment achieved significant stress relief and secondary phase precipitation strengthening, resulting in a peak microhardness of 78.8 HV. The study demonstrates that 350 °C homogenization annealing synergistically improves both the corrosion resistance and mechanical properties of hot-rolled 5083 aluminum alloy, providing valuable insights for optimizing its heat treatment process. Full article

Wire Arc Additive Manufacturing (WAAM), also known as Wire Arc Directed Energy Deposition, is used for fabricating large metallic components with high deposition rates. However, the process often leads to residual stress, distortion, defects, undesirable microstructure, and inconsistent bead geometry. These challenges necessitate reliable in-situ monitoring for process understanding, quality assurance, and control. While several reviews exist on in-situ monitoring in other additive manufacturing processes, systematic coverage of sensing methods specifically tailored for WAAM remains limited. This review fills that gap by providing a comprehensive analysis of existing in-situ monitoring approaches in WAAM, including thermal, optical, acoustic, electrical, force, and geometric sensing. It compares the relative maturity and applicability of each technique, highlights the challenges posed by arc light, spatter, and large melt pool dynamics, and discusses recent advances in real-time defect detection and control, process monitoring, microstructure and property prediction, and minimization of residual stress and distortion. Apart from providing a synthesis of the existing literature, the review also provides research needs, including the standardization of monitoring methodologies, the development of scalable sensing systems, integration of advanced AI-driven data analytics, coupling of real-time monitoring with multi-physics modeling, exploration of quantum sensing, and the transition of current research from laboratory demonstrations to industrial-scale WAAM implementation. Full article

High-yielding dairy cows are particularly vulnerable to heat stress, a challenge that climate change exacerbates. To quantify the impact of climatic variables on productivity, we applied a random parameter stochastic production frontier model to the United States Department of Agriculture (USDA) census data from 1978 to 2022 for 179 dairy counties, allowing us to decompose total factor productivity growth (TFPG). Our analysis indicates that technological advancements were the primary driver of TFPG, amounting to 2.52% annually. While these gains are modestly constrained by heat stress, the average impact on the overall TFPG rate was only 0.008% per year. This minimal impact is consistent with the adoption of strategies such as cooling systems and improved management. Even in the most affected counties, the effect remained slight, with the largest reduction reaching 0.08%. This limited impact suggests that the sector’s adoption of technologies and management strategies appears to have mitigated potential productivity losses. This study highlights that future research is needed to quantify the direct impact of specific on-farm adaptation strategies on dairy productivity to inform well-targeted policy recommendations. Full article

Background/Objectives: Cement augmentation of cephalomedullary head elements can improve the purchase of osteoporotic bone; however, it does not eliminate the need for accurate implant positioning or the preservation of sliding. We report the case of an 87-year-old woman who underwent intramedullary nailing with a cement-augmented helical blade for intertrochanteric fracture. Methods: This is a single-patient case report. Calibrated radiographic measurements—tip–apex distance (TAD), calcar-referenced TAD (CalTAD), neck–shaft angle (NSA), and telescoping—were obtained immediately postoperatively and at 4, 7, 12, and 15 months. CT was performed at postoperative week 1 and at failure, and MRI was performed for clinical deterioration. In addition, a targeted narrative review summarizes the evidence on the head-element position, sliding behavior, reduction alignment, and augmentation. Results: Immediate postoperative indices were within the accepted targets: TAD 22.6 mm, CalTAD 22.8 mm, NSA 134°, with the head element inferior on the anteroposterior view and central on the lateral view. Rehabilitation proceeded with full weight bearing as tolerated. Early telescoping was minimal (3.8–3.9 mm). Between 7 and 15 months, progressive varus with shortening of TAD/CalTAD and little additional telescoping was observed, radiographically consistent with relative proximal migration of the head–cement complex and a cleavage plane along the inferior cement mantle, culminating in a subcapital femoral neck fracture with the implant in situ. Emphasis should be placed on accurate implant positioning and preservation of sliding capacity, because cement augmentation alone may not prevent mechanical failure when the implant position or load transfer is suboptimal. Conclusions: Cement augmentation stiffens the interface and reduces micromotion but does not neutralize malposition-induced stresses. Accurate positioning, preservation of sliding, and timely conversion when sliding fails to progress are advisable; these findings are hypothesis-generating from a single case. We propose a position- and sliding-based decision guide to support clinical decision-making; its usefulness remains to be validated in larger studies. Full article

Management of secondary hyperparathyroidism (SHPT) in chronic kidney disease (CKD) has evolved dramatically over the past five decades, driven by discoveries that have fundamentally reshaped our understanding of the vitamin D endocrine system and its role in disease progression. This review synthesizes the key pathophysiological insights and clinical evidence underlying three critical paradigm shifts. The first shift moved beyond simple calcitriol replacement with the development of selective vitamin D receptor activators (VDRAs) designed to minimize hypercalcemia while maximizing PTH suppression. Crucially, these analogs revealed unexpected survival benefits, suggesting protective VDR actions extending beyond mineral metabolism. The second shift recognized the profound prevalence and independent mortality risk associated with nutritional vitamin D (25(OH)D) deficiency in CKD. This highlighted the kidney’s complex role in maintaining systemic 25(OH)D supply and the importance of extrarenal vitamin D activation, although optimal assessment, targets, and supplementation strategies remain highly controversial due to CKD-specific pathophysiology (e.g., megalin loss, impaired uptake, obesity effects) and complex dosing paradoxes. The third, and most impactful, shift centers on the FGF23-Klotho axis. Pathologically high FGF23 is now established as a direct cardiovascular and skeletal toxin, acting via Klotho-independent pathways in CKD, while the profound deficiency of the protective, anti-aging hormone Klotho exacerbates systemic damage (inflammation, oxidative stress, impaired autophagy). This creates a major therapeutic dilemma, as VDRAs induce protective Klotho but worsen toxic FGF23, while calcimimetics do not increase FGF23 but offer no Klotho benefit. Furthermore, this complex interplay is obscured by significant limitations in accurately measuring FGF23 isoforms, soluble Klotho, and true vitamin D status. These paradigm shifts reveal a complex pathophysiology far beyond simple PTH control, demanding a move towards nuanced, potentially combined therapeutic strategies that balance FGF23 burden with Klotho preservation. Overcoming the profound diagnostic limitations to accurately monitor this axis and guide personalized therapy represents the critical next frontier in improving outcomes for patients with CKD. Full article