Search Results (19,193)

This paper focuses on the design of a three-dimensional trajectory tracking controller for underactuated quadrotor-like autonomous underwater vehicles (QAUVs) subject to actuator saturation. A hand position method with a signum function is proposed to handle the under-actuation of QAUVs, while avoiding trajectory tracking in the opposite direction. The dynamic surface control (DSC) technique is integrated to eliminates the complexity explosion problem of standard backstepping. An auxiliary dynamic system is employed to handle input saturation. By using Lyapunov stability theory and phase plane analysis, it is proved that the proposed control law ensures that the QAUVs converge to the desired position with arbitrarily small errors, while guaranteeing the uniform ultimate boundedness of the whole closed-loop system. Comparative simulation results verify the effectiveness of the proposed control law. Full article

Ternary hybrid nanofluid have been revealed to possess a wide range of application disciplines reaching from biomedical engineering, detection of cancer, over or photovoltaic panels and cells, nuclear power plant engineering, to the automobile industry, smart cells and and eventually to heat exchange systems. Inspired by the recent developments in nanotechnology and in particular the high potential ability of use of such nanofluids in practical problems, this paper deals with the flow of a three phase nanofluid of MWCNT-Au/Ag nanoparticles dispersed in blood in the presence of a bidirectional stretching sheet. The model derived in this study yields a set of linked nonlinear PDEs, which are first transformed into dimensionless ODEs. From these ODEs we get a dataset with the help of MATHEMATICA environment, then solved using AI-based technique utilizing Levenberg Marquardt Feedforward Algorithm. In this work, flow characteristics under varying physical parameters have been studied and analyzed and the boundary layer phenomena has been investigated. In detail horizontal, vertical velocity profiles as well as temperature distribution are analyzed. The findings reveal that as the stretching ratio of the surface coincide with an increase the vertical velocity as the surface has thinned in this direction minimizing resistance to the fluid flow. Full article

The photocatalytic efficiency of TiO₂ was significantly enhanced by coupling with WO₃ to form a TiO₂/WO₃ heterostructure, designed to operate effectively under UV-LED irradiation. The nanocomposites were synthesized via a hydrothermal route, and their activity was evaluated through the degradation of the pharmaceutical pollutant venlafaxine. Contaminants are rarely addressed in photocatalytic studies. Unlike a simple physical mixture of commercial TiO₂ and WO₃ powders, the hydrothermally synthesized TiO₂/WO₃ photocatalyst exhibited superior efficiency, attributable to its nanoscale dimensions achieved via the hydrothermal route, which promoted improved charge carrier separation, enhanced surface homogeneity, and the formation of an effective heterojunction interface. An optimization study varying the WO₃ content (5, 10, 20, and 30 wt.%) within the TiO₂ revealed that the 10 wt.% WO₃ composition achieved the highest performance, with ~52% venlafaxine degradation within 60 min. SEM, TEM, FTIR, Raman spectroscopy, XRD, and UV-Vis DRS revealed the successful incorporation of WO3 into the TiO₂ matrix, confirming phase purity and composition-dependent structural evolution of the nanocomposite, and evidencing extended light absorption and superior charge-transfer properties. Importantly, the optimized photocatalyst thin film retained excellent stability and reusability, maintaining high degradation efficiency over three consecutive cycles with negligible activity loss, which avoids slurry separation. These findings establish hydrothermally synthesized TiO₂/10%WO₃ thin film heterostructures as effective and sustainable photocatalytic platforms for the removal of pharmaceutical pollutants in wastewater under UV-LED irradiation. Full article

This study evaluated the effect of dietary supplementation with different levels of spray-dried phenolic compounds, extracted from olive mill wastewater, on the volatile compound profile of Caciotta cheese produced from cow’s milk. Thirty dairy cows were divided into three groups and fed diets containing 0% (C), 0.1% (T0.1), and 0.2% (T0.2) polyphenols on a dry matter basis. Milk from each group was used in three cheesemaking sessions, and 27 cheese samples ripened for 21 days were analyzed. Volatile compounds were extracted using solid phase microextraction (SPME) coupled with mass spectrometry, while the odour fingerprint was assessed using an electronic nose (PEN3). Principal Component Analysis (PCA) revealed a clear separation among groups, indicating distinct aromatic profiles associated with dietary polyphenol levels. In summary, incorporating by-products from olive mill wastewater into the diets of dairy cows can significantly affect the aroma of cheese. This approach represents a sustainable and innovative strategy that promotes waste valorization, reduces environmental impact, and supports circular economy principles by transforming a pollutant into a valuable additive. Full article

(1) Background: Caffeine is one of the most widely consumed psychoactive substances. Its safety profile and short half-life make it an ideal drug model for studying the pharmacokinetics of caffeine. This study aimed to develop a method for determination of caffeine in a small volume of saliva (200 µL). (2) Methods: Solid-phase extraction was employed to isolate caffeine from saliva, followed by quantitative analysis using liquid chromatography coupled with diode-array detection. Chromatographic separation was achieved on a C18 column, using a gradient mobile phase of acetonitrile and 0.1% formic acid. (3) Results: The method was validated for selectivity, linearity, precision, and accuracy. Linearity was established over the range of 10–10,000 ng/mL (R² = 0.995). The coefficients of variation for intra- and inter-day precision for the three tested caffeine concentrations did not exceed 12.11%. Recovery from spiked saliva samples exceeded 90.53%. The developed method was applied to preliminary studies to follow the pharmacokinetics of caffeine in saliva. The concentration of the substance was studied in the saliva obtained from a volunteer after espresso consumption. (4) Conclusions: The developed method will offer a reliable approach for non-invasive caffeine monitoring in clinical and research applications. Full article

Drone-based target detection using visible and thermal (RGB-T) images is critical in disaster rescue, intelligent transportation, and wildlife monitoring. However, persons typically occupy fewer pixels and exhibit more varied postures than vehicles or large animals, making them difficult to detect in unmanned aerial vehicle (UAV) remote sensing images with complex backgrounds. We propose a novel progressive target-aware network (PTANet) for person detection using RGB-T images. A global adaptive feature fusion module (GAFFM) is designed to fuse the texture and thermal features of persons. A progressive focusing strategy is used. Specifically, we incorporate a person segmentation auxiliary branch (PSAB) during training to enhance target discrimination, while a cross-modality background mask (CMBM) is applied in the inference phase to suppress irrelevant background regions. Extensive experiments demonstrate that the proposed PTANet achieves high accuracy and generalization performance, reaching 79.5%, 47.8%, and 97.3% mean average precision (mAP)@50 on three drone-based person detection benchmarks (VTUAV-det, RGBTDronePerson, and VTSaR), with only 4.72 M parameters. PTANet deployed on an embedded edge device with TensorRT acceleration and quantization achieves an inference speed of 11.177 ms (640 × 640 pixels), indicating its promising potential for real-time onboard person detection. The source code is publicly available on GitHub. Full article

As stability is one of the most important property of any system, studying it is paramount when performing a power-hardware-in-the-loop simulation in an experimental setup. To guarantee the proper operation of such a system, a thorough understanding of the critical issues regarding the dynamics of the power amplifier, the real-time simulated system and the hardware under test is required. Thus, this paper provides a detailed analysis of the correct design of the real-time simulation modeling for the secure and reliable execution of power-hardware-in-the-loop simulations involving power electronic devices in an experimental setup. Specifically, the stability region of a power-hardware-in-the-loop simulation in an experimental AC microgrid setup involving two parallel three-phase grid-following inverters with LCL filters is studied. Through experimental testing, the stability boundaries of the power-hardware-in-the-loop simulation in the experimental setup is determined, demonstrating a direct relationship between the short-circuit ratio of the utility grid and the cutoff frequency of the feedback current filter. Experimental evidence confirms the capability of the AC microgrid setup to achieve smooth transitions between diverse operating conditions and determine stability boundaries with parameter variations. This research provides practical design guidelines for modeling and the real-time simulation to ensure stability in the power-hardware-in-the-loop simulations in experimental setups involving actual grid-following inverters, specifically using an Opal-RT platform with a voltage-source ideal transformer model and parameter variations in the short-circuit ratio from 2 to 20, the line impedance ratio $X/R$ from 7 to 10, and the feedback-current-filter cutoff frequency from 100 to 1000 kHz. Full article

Background/Objectives: Alcohol and smoking during pregnancy may be associated with several complications, but the underlying mechanism is still unclear. The aim of this study was to evaluate the role of oxidative stress induced by smoking and alcohol during pregnancy and their effects on fetal and neonatal outcomes. Material and methods: We considered pregnant women at term. Validated questionnaires were used to investigate smoking and alcohol habits. Ultrasound was performed to evaluate fetal weight, amniotic fluid index, and maternal-fetal Doppler velocimetry. At the time of delivery, we collected a tuft of maternal hair, maternal venous blood, and cord blood. In these samplings we determined in phase I nicotine, cotinine, and ethyl glucuronide on the maternal keratin matrix with the gas chromatography-mass spectrometry technique. In phase II, the Free Oxygen Radicals Test (FORT) and Free Oxygen Radical Defense (FORD) test were used to assess circulating reactive oxygen species (ROS). Results: 119 pregnant patients were enrolled (n = 62 for smoking and n = 57 for alcohol). Twenty-six patients (42%) out of 62 were active smokers. Three patients (5%) out of 57 were alcoholic consumers. Mean neonatal weight and mean placental weight were significantly lower for active smokers (p = 0.0001). The neonatal weight was in the 1st–2nd percentile for all alcohol abusers. Considering two subgroups (n = 10 non-smokers and n = 10 smokers) for ROS determination, a statistically significant higher oxidative stress in the blood of smoking patients was evidenced (p < 0.0001). In cord blood the differences were not statistically significant (p = 0.2216). Conclusions: Fetal growth restriction was present in the group of active smokers and in patients with alcohol abuse. Oxidative stress was higher in smoking patients than in non-smokers. However, in cord blood, FORT was negative in all cases, suggesting a protective mechanism in utero. Given the limited sample size, the results obtained are preliminary and require future studies. Full article

Urban climate readiness requires multi-dimensional implementation strategies that operate effectively across both spatial scales and time horizons. This article introduces a multi-scale, phased model designed to support integrated climate action by distinguishing between metropolitan and building levels and addressing three core domains: physical resilience, decarbonization, and social/community engagement. The framework conceptualizes metropolitan and building scales as analytically distinct but operationally linked, allowing strategies to reflect the different systems, stakeholders, and capacities at each level. It also outlines a three-phase progression—Initial (assessment and goal setting), Readiness (planning and implementation), and Steady-State (monitoring and iterative adjustment)—to support staged, adaptive deployment. Each phase includes sample metrics and SMART goals that can be tailored to local context and tracked over time. By integrating theoretical insights with practical implementation tools, the framework offers a flexible yet rigorous approach for advancing urban sustainability. It emphasizes the importance of aligning technical interventions with institutional capacity and community participation to enhance effectiveness and equity. This model contributes to both planning theory and applied sustainability efforts by providing a structured pathway for cities to enhance climate readiness across systems and scales. Full article

The conceptual design phase in architecture establishes the foundation for subsequent design decisions and influences up to 80% of a building’s lifecycle environmental impact. While Building Information Modeling (BIM) demonstrates transformative potential for sustainable design, its application during conceptual design remains constrained by perceived technical complexity and limited support for abstract thinking. This research examines how BIM tools can facilitate conceptual design through diagrammatic reasoning, thereby bridging technical capabilities with creative exploration. A mixed-methods approach was employed to develop and validate a Diagrammatic BIM (D-BIM) framework. It integrates diagrammatic reasoning, parametric modeling, and performance evaluation within BIM environments. The framework defines three core relationships—dissection, articulation, and actualization—which enable transitions from abstract concepts to detailed architectural forms in Revit’s modeling environments. Using Richard Meier’s architectural language as a structured test case, a 14-week quasi-experimental study with 19 third-year architecture students assessed the framework’s effectiveness through pre- and post-surveys, observations, and artifact analysis. Statistical analysis revealed significant improvements (p < 0.05) with moderate to large effect sizes across all measures, including systematic design thinking, diagram utilization, and academic self-efficacy. Students demonstrated enhanced design iteration, abstraction-to-realization transitions, and performance-informed decision-making through quantitative and qualitative assessments during early design stages. However, the study’s limitations include a small, single-institution sample, the absence of a control group, a focus on a single architectural language, and the exploratory integration of environmental analysis tools. Findings indicate that the framework repositions BIM as a cognitive design environment that supports creative ideation while integrating structured design logic and performance analysis. The study advances Education for Sustainable Development (ESD) by embedding critical, systems-based, and problem-solving competencies, demonstrating BIM’s role in sustainability-focused early design. This research provides preliminary evidence that conceptual design and BIM are compatible when supported with diagrammatic reasoning, offering a foundation for integrating competency-based digital pedagogy that bridges creative and technical dimensions of architectural design. Full article

Electromagnetic Railguns Face Severe Ablation and Melting Risks Due to Extremely High Transient Thermal Loads During High-Speed Launching, Directly Impacting Launch Reliability and Service Life. To address this thermal management challenge, this study proposes and validates the effectiveness of spray cooling technology. Leveraging its high heat transfer coefficient, exceptional critical heat flux (CHF) carrying capacity, and strong transient cooling characteristics, it is particularly suitable for the unsteady thermal control during the initial launch phase. An experimental platform was established, and a three-dimensional numerical model was developed to systematically analyze the dynamic influence mechanisms of nozzle inlet pressure, flow rate, spray angle, and spray distance on cooling performance. Experimental results indicate that the system achieves maximum critical heat flux (CHF) and rail temperature drop at an inlet pressure of 0.5 MPa and a spray angle of 0°. Numerical simulations further reveal that a 45° spray cone angle simultaneously achieves the maximum temperature drop and optimal wall temperature uniformity. Key parameter sensitivity analysis demonstrates that while increasing spray distance leads to larger droplet diameters, the minimal droplet velocity decay combined with a significant increase in overall momentum markedly enhances convective heat transfer efficiency. Concurrently, increasing spray distance effectively improves rail surface temperature uniformity by optimizing the spatial distribution of droplet size and velocity. Full article

White tea quality is primarily determined by its chemical composition, which varies significantly among cultivars. This study aimed to elucidate the chemical basis underlying quality differentiation in Baimudan white tea produced from three major Fujian tea cultivars: “Zhenghe Dabaicha” (ZHDB), “Fuan Dabaicha” (FADB), and “Fuding Dahaocha” (FDDH). Headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS), liquid chromatography–mass spectrometry (LC-MS), and quantitative descriptive analysis (QDA) were employed to characterize volatile compounds, amino acids, and saccharides. Odor Activity Values (OAVs) and Taste Activity Values (TAVs) were calculated to identify key contributors to sensory perception. Results showed that theanine, glutamic acid, asparagine, and serine were the primary contributors to umami taste, especially in ZHDB and FADB. Sweetness differences were largely due to sucrose, serine, and asparagine. OAV analysis further identified 22 critical aroma compounds: methyl salicylate, linalool, and β-ionone predominantly imparted floral notes, while β-ocimene, benzaldehyde, and geraniol enhanced sweet and fruity aromas. In contrast, (Z)-3-hexenol, (Z)-3-hexenal, and (E)-2-hexenal contributed grassy and refreshing characteristics, together defining the unique aroma profiles of each cultivar. This study provides an integrated chemical and sensory framework for understanding white tea quality variation, offering a theoretical basis for targeted flavor modulation. Full article

This study focuses on the characterization of MoN thin films deposited by the direct current magnetron sputtering (dcMS), mid-frequency magnetron sputtering (mfMS), and inductively coupled plasma magnetron sputtering (ICPMS) methods. Two mixed metallic phases, namely, α-Mo and γ-Mo₂N, were detected from the film obtained using the dcMS, whereas only single γ-Mo₂N phase was detected from the films obtained using the mfMS and ICPMS. Furthermore, the residual stress of the deposited thin films was strongly dependent on the sputtering process. As the mfMS and ICPMS deposition process were introduced, the film morphology changed from a porous columnar to a dense structure with finer grains than film deposited using dcMS. The surface roughness and crystal grain size of coated films were investigated by atomic force microscopy and X-ray diffraction analysis methods. Furthermore, the variation in hardness and electrical resistivity of the MoN thin films deposited by three plasma-enhanced magnetron sputtering was explained on the basis of microstructure and residual stress of the thin films. Full article

Background: This study investigated sex differences in foot arch structure and function, and their impact on postural control and energy flow during dynamic tasks. Findings aim to inform sex-specific training, movement assessment, and injury prevention strategies. Methods: A total of 108 participants (53 males and 55 females) underwent foot arch morphological assessments and performed a sit-to-stand (STS). Motion data were collected using an infrared motion capture system, three-dimensional force plates, and wireless surface electromyography. A rigid body model was constructed in Visual3D, and joint forces, segmental angular and linear velocities, center of pressure (COP), and center of mass (COM) were calculated using MATLAB. Segmental net energy was integrated to determine energy flow across different phases of the STS. Results: Arch stiffness was significantly higher in males. In terms of postural control, males exhibited significantly lower mediolateral COP frequency and anteroposterior COM peak velocity during the pre-seat-off phase, and lower COM displacement, peak velocity, and sample entropy during the post-seat-off phase compared to females. Conversely, males showed higher anteroposterior COM velocity before seat-off, and greater anteroposterior and vertical momentum after seat-off (p < 0.05). Regarding energy flow, males exhibited higher thigh muscle power, segmental net power during both phases, and greater shank joint power before seat-off. In contrast, females showed higher thigh joint power before seat-off and greater shank joint power after seat-off (p < 0.05). Conclusions: Significant sex differences in foot arch function influence postural control and energy transfer during STS. Compared to males, females rely on more frequent postural adjustments to compensate for lower arch stiffness, which may increase mechanical loading on the knee and ankle and elevate injury risk. Full article

Background: Bioelectrical impedance analysis (BIA) is a widely used field technique for assessing body composition in football. However, its reliance on population-specific regression equations limits its accuracy. Objective: This scoping review aimed to map the scientific literature on BIA applications in professional and semi-professional football, highlighting uses, limitations, and research opportunities. Methods: A comprehensive search was conducted in the scientific databases PubMed, EMBASE, Web of Science, and SPORTDiscus. Identified studies involved the use of BIA in professional and semi-professional football players (≥16 years) in the context of routine training and competition. Results: From 14,624 records, 39 studies met the inclusion criteria and were included. Three main applications were identified: (1) quantitative body composition assessment, (2) qualitative/semi-quantitative analysis (e.g., bioelectrical impedance vector analysis (BIVA)), and (3) muscle health and injury monitoring. Seven specific research areas emerged, including hydration monitoring, cross-method validation of body composition analyses, development of predictive models, sport phenotype identification, tracking training adaptations, performance/load assessment via phase angle, and localized BIA for injury diagnosis and recovery. Conclusions: While quantitative BIA estimates may lack individual-level precision, raw parameter analyses may offer valuable insights into hydration, cellular integrity, and muscle injury status, yet further research is needed to fully realize these applications. Full article