Search Results (8,656)

Ultrasound–assisted additive manufacturing forms bonds through rapid interfacial events that are difficult to observe in situ, particularly because the deposition tool moves continuously. This study presents an energy–based acoustic framework for detecting and timing these interfacial events, demonstrated on the Resonant–Assisted Deposition (RAD) process. Rather than measuring absolute energy, the method treats the signal power of each channel as a relative indicator of acoustic energy and tracks how wave propagation is altered in structure–borne and airborne pathways, recorded by two AE sensors on the deposition head and substrate, and an airborne microphone. Because the interface acts on all pathways at once, its activity appears as a common–mode variation of the head and substrate signal powers, distinct from the opposing trade–off seen during free tool motion, and this signature locates the interfacial activities within deposition cycles. Two time–domain features segment the window: the Interfacial Slipping Duration (ISD), associated with the slip stage, and the Interfacial Consolidation Duration (ICD), the subsequent bond formation stages; together they give the interfacial–activity duration $T_{IA}$. The measured ISD is consistent with an independently reported slip stage thermal response, and the same signal–derived windows confine the time–frequency analysis to the interval where ultra–harmonic interfacial content appears. Across controlled changes in excitation frequency and substrate temperature, the features remain extractable and respond in distinguishable ways, indicating repeatability and sensitivity. The method provides a physically interpretable, fixed–sensor basis for characterizing the timing of interfacial events in a moving–tool process, intended for in–situ process monitoring. Full article

Enterovirus A71 (EV-A71), belonging to the Picornaviridae family, is the primary causative agent of hand, foot, and mouth disease (HFMD) in children under five years of age, and no specific broad-spectrum antiviral therapy is currently available. Despite having extensive research on the EV-A71 3C protease, another nonstructural protein, the 2C protein, which is a highly conserved protein and a member of the ATPases Associated with diverse cellular Activities (AAA+) helicase family, lacks conclusive details of its mechanism. This study, thereby, performed a comprehensive analysis of the wild-type EV-A71 2C protein by studying the role of Zn²⁺ in structural stability and determining the binding site with two pronounced inhibitors—fluoxetine 12b and dibucaine 6i—as the positive controls via the blind docking method. Then, a virtual screening on a Vietherb database (5071 metabolites from Vietnamese natural sources) yielded 20 top-ranked compounds, which were selected for further molecular dynamics (MD) simulation and cross-variant evaluation. Among these, CID 101282068 extracted from Diospyros montana exhibited overall good, predicted binding affinity (docking score of −9.8 kcal/mol and G_bind = −33.27 kcal/mol) and sustained the highest number of persistent hydrogen bonds with critical residues at the oligomerization interface. Further validation against 23 EV-A71 2C variants highlights its hypothetical broad-spectrum characteristics and can be considered a promising lead candidate targeting EV-A71 2C multimers. Full article

Background: Post-curing may influence the properties of 3D-printed ceramic-filled resin restorations. This study compared four post-curing protocols for adaptation and microtensile bond strength (µTBS) of cemented, thermocycled DLP-printed inlays. Methods: Seventy-six maxillary premolars with standardised MOD cavities received inlays randomised (n = 19) to standard post-curing in air (SP), glycerine-immersed post-curing (GP), or SP plus microwave heating in glycerine (MG; 800 W nominal, 50 s) or autoclaving (AT; 121 °C). After cementation and 5000 thermocycles, adaptation discrepancy—a composite of post-curing change, seating, cement layer and ageing—was measured at 11 points by triple-scan superimposition before µTBS testing of the inlay–cement–dentine complex and failure-mode analysis. Results: Discrepancy (F(3, 37.6) = 24.47, p < 0.001) and µTBS (F(3, 39.8) = 6.09, p = 0.002) differed among protocols. MG showed the largest discrepancy (104.42 ± 13.57 µm; p < 0.01 versus all groups), lower µTBS than GP and SP (15.04 ± 5.13 versus 21.58 ± 4.35 and 20.19 ± 5.33 MPa) and predominantly adhesive failures (68.4% of teeth; interface unidentified). GP had the numerically lowest discrepancy (77.09 ± 5.48 µm), but its 7.7 µm difference from SP was within measurement uncertainty and not robust to sensitivity analysis. AT did not differ from SP. Conclusions: The complete MG protocol was associated with greater discrepancy and lower µTBS; GP did not differ robustly from SP. Full article

Natural-fiber-based composite materials are gaining popularity because they are lightweight, renewable, and more sustainable than existing synthetic fiber composites, offering numerous benefits for structural engineering applications. However, the lack of adhesion at natural-fiber–matrix interfaces due to the non-polar hydrophobic nature of the fibers and hydrophobic epoxy matrices produces gaps due to void formation during manufacturing. Also, the non-uniform distribution of natural fibers and the reinforcement make the composite perform inefficiently, prone to brittleness, have lower temperature resistance and lack proper bonding between fibers. The present research work aimed to achieve the maximum flexural, tensile, compressive strength, thermal resistance and toughness of areca–hemp hybrid epoxy composites with nano-silica (AHNS) at varying percentages (1 wt%, 2 wt%, 3 wt%, and 4 wt%) as reinforcement. The results showed that AHNS-2 with 2 wt% of nano-silica yielded superior flexural and compression strength and Shore-D hardness (64.40 N/mm², 57.46 N/mm² and 83, respectively); AHNS-4 with 4 wt% nano-silica exhibited the best performance in terms of tensile strength, toughness and maximum degradation-rate temperature (61.90 N/mm², 81.99 J/m and 377.4 °C, respectively). The SEM morphology analysis revealed fiber pull-out, matrix cracks, fiber breakage, and fiber–matrix interfacial characteristics. These microstructural features showed a considerable impact on the mechanical properties of the composites, especially on density, hardness, strength and toughness. The elemental analysis revealed that carbon (64.92%) and oxygen (33.08%) were the predominant elements present, although silicon (2%) was also present in AHNS-2. The presence of silicon provided evidence of the localized incorporation of nano-silica within the epoxy matrix. It was observed that the mechanical properties of AHNS with 1–4 wt% nano-silica were significantly better compared to the unfilled composite (AHNS-0 wt% nano-silica). Full article

A systematic SCAPS-1D simulation was performed to evaluate the effects of charge-transport-layer selection, MAPbI₃ crystal phase, TiO₂ modification, and key device parameters on the photovoltaic performance of MAPbI₃-based perovskite solar cells. Twenty-five combinations of five electron transport layers (ETLs) and five hole transport layers were first screened using tetragonal MAPbI₃ as the absorber. The TiO₂/P₃HT combination exhibited the highest power conversion efficiency (PCE) of 23.653% and was selected for subsequent analysis. Comparison of cubic, orthorhombic, and tetragonal MAPbI₃ showed that the tetragonal phase delivered the highest PCE, primarily owing to its higher short-circuit current density despite its relatively lower open-circuit voltage. Li-, Co-, Mg-, and Al-doped TiO₂ ETLs were then evaluated, among which Mg:TiO₂ produced the largest and most consistent performance improvement, increasing the PCE of the tetragonal device to 23.951%, mainly through an enhancement in fill factor. The selected Glass/FTO/Mg:TiO₂/tetragonal-MAPbI₃/P₃HT/Au device was further optimized by varying the absorber thickness, Mg:TiO₂ donor concentration, MAPbI₃ bulk defect density, interface defect density, and back-contact work function. Under the stepwise-selected low-defect conditions, the device achieved a simulated open-circuit voltage of 1.166 V, short-circuit current density of 27.600 mA cm⁻², fill factor of 87.580%, and PCE of approximately 28.18%. The results highlight the importance of jointly optimizing absorber properties, electron-transport characteristics, defect density, and contact energetics, and they provide a theoretical basis for narrowing the experimental design space of high-performance MAPbI₃ perovskite solar cells. Full article

The integration of wireless power transfer (WPT) technology with fuel cell hybrid electric vehicles (FCHEVs) offers a viable solution to enhance energy accessibility, increase flexibility, and improve driving sustainability. However, the coordinated operation of wireless charging systems, hybrid energy-storage systems (HESSs), and vehicular propulsion units introduces significant control challenges due to nonlinear dynamics, parameter uncertainties, and rapidly varying load demands. To overcome these limitations, this paper presents a WPT–FCHEV architecture comprising an LCC-S-based wireless charging system, a fuel cell source, a battery, ultracapacitor-based HESS, and an induction-motor (IM) drive. Comprehensive mathematical models of the respective charging and propulsion stages are developed by incorporating the dynamics of the LCC-S-compensated WPT, energy-storage units, bidirectional DC–DC converter interfaces, DC bus, and IM drive. A constant-coefficient-based finite-time sliding mode controller (CCFTSMC) is designed to regulate fuel cell current, battery current, ultracapacitor current, DC bus voltage, and motor speed, thereby ensuring finite-time convergence and robust tracking performance under dynamic operating conditions. The efficacy of the proposed framework is investigated through extensive simulation in MATLAB/Simulink under charging and propulsion scenarios. The obtained results demonstrate accurate current regulation and power allocation, effective DC bus voltage regulation, good speed tracking, and stable wireless charging operation. Compared with the conventional Backstepping controller, the proposed CCFTSMC achieves a 93.41% reduction in settling time and a 38.06% reduction in rise time, demonstrating superior transient and steady-state tracking performance with reduced RMSE and MAE tracking errors. Robustness analysis under ±20% parameter variations further demonstrates stable operation without controller retuning, with WPT power maintained between 309.5 and 310.6 W under mutual-inductance variation and only marginal speed RMSE variation under converter inductance and resistance uncertainties. These results confirm the robustness and effectiveness of the proposed control strategy for WPT–FCHEV applications. Full article

Automated feeding in cage-based rabbit production is challenging because cage geometry and limited workspace require a compact manipulator with sufficient reach, low mass, and reliable task-level positioning. This study developed a lightweight five-degree-of-freedom manipulator integrated with a vision-guided positioning framework for cage-based rabbit feeding applications. The prototype achieved an effective task reach of 1.20 m with a total mass of 12.37 kg. The design incorporated lightweight carbon-fiber-reinforced polymer (CFRP) long-span links, integrated actuators selected according to joint torque requirements, task-constrained kinematics, closed-form inverse kinematics, and Cartesian trajectory planning. A red–green–blue and depth (RGB-D) localization interface used four ordered feed-port keypoints and a horizontal-plane constraint to provide three-dimensional upper-tier task targets for the manipulator. All representative task points were numerically reachable under the defined software joint limits, and the maximum planned joint velocity was 0.525 rad s${}^{-1}$. Component-level linear-static finite-element analysis predicted no yielding in the four analyzed aluminum components under the simplified conservative 5 kg verification load case. Static loading of the assembled arm produced mean downward displacements of 3.0–20.0 mm at the J5 flange under 1–5 kg loads. Laboratory evaluation demonstrated three-dimensional repeatability radii of 1.68–4.63 mm. Across four upper-tier locations, the mean Euclidean feed-port localization error ranged from 9.01 to 20.47 mm, with all 80 trials satisfying the $\pm 20$ mm-per-axis criterion. The mean tool center point (TCP)-equivalent end-point error ranged from 18.23 to 37.15 mm. These laboratory results support the feasibility of the developed manipulator for upper-tier vision-guided positioning in rabbit-feeding geometry, while indicating that multi-point calibration and spatial compensation are needed to further reduce system-level positioning error. Validation was limited to laboratory testing; no feed was discharged and no rabbit-house operation was evaluated. Full article

An emerging class of electromagnetic energy harvesters, primarily designed to scavenge energy from human motion, sea waves, or sporadic mechanical vibrations, generates impulsive voltage waveforms rather than conventional sinusoidal ones. For such harvesters, usually employed for powering wireless sensor network nodes, this paper presents an in-depth investigation of double-stage AC/DC conversion interfaces aimed at evaluating and comparing their performance in energy extraction. Closed-form expressions are derived for widely adopted topologies consisting of full-bridge or voltage doubler rectifiers followed by DC/DC converters that exhibit either constant-voltage or constant-resistance behavior at their input terminals. The derived expressions provide valuable design insight, showing that no topology is universally preferable under all operating conditions; therefore, design guidelines are provided to support the selection and optimization of the most appropriate configuration. The analytical results show good agreement with measurements performed on interface prototypes assembled using off-the-shelf components, with a relative error below 4% at the maximum-energy points for all the tested configurations. The experimental validation confirms the accuracy of the developed models and their practical relevance for the analysis and design of interfaces for impulsive electromagnetic energy harvesters. Full article

Maintaining upright stability in tandem-wheel robotic systems is particularly challenging during stationary and low-speed operation, where steering-induced stabilization and gyroscopic effects become limited. Also, alternative mechanisms such as reaction wheels, control-moment gyroscopes, and movable balancing masses can increase mass and mechanical complexity. To address these limitations, this paper proposes an elevated, vectored differential-propeller-thrust approach for active roll stabilization and presents the design, prototyping, and experimental validation of a self-balancing tandem-wheel mobile robotic system employing the proposed principle. Two laterally oriented ducted propeller fans are mounted above the vehicle’s center of mass to increase the available roll-moment arm, while thrust vectoring provides an additional contribution to the corrective rolling moment. The system integrates a perpendicular drivetrain, front-wheel steering mechanism, inertial sensing, wireless communication, and a real-time proportional–integral–derivative (PID) controller utilizing direct gyroscope roll-rate feedback. The system is characterized through geometry-based roll-moment and dynamic analyses, including open-loop pole analysis and a Routh–Hurwitz assessment of the PID-controlled roll dynamics. A Python-based supervisory interface provides wireless command generation, real-time telemetry visualization, and data logging. Experimental evaluation includes static stability, dynamic roll-reference tracking, and variable-speed driving-performance tests. The analytical results identify an open-loop unstable upright equilibrium and reveal the mechanical and actuator parameter conditions for local asymptotic stability under PID-controlled differential thrust. The results of the experiments demonstrate effective upright stabilization, accurate roll-reference tracking, smooth differential-thrust allocation, and reliable attitude regulation during stationary and low-speed operation. The principal contribution is the development and experimental demonstration of an elevated, vectored differential-thrust stabilization architecture for active roll control of a slender tandem-wheel robotic platform, providing a foundation for further development of dynamically stabilized single-track robotic systems. Full article

The cyclic response of Steel-Reinforced Concrete (SRC) columns is governed by the interaction between the embedded structural steel section and the surrounding concrete. However, most nonlinear finite element studies assume a perfect bond at the steel–concrete interface, neglecting interface slip that may considerably influence the structural response. This study investigates the effects of steel–concrete interface conditions on the cyclic behavior of SRC columns through three-dimensional nonlinear finite element analyses conducted in ABAQUS. The developed modeling approach was first validated against experimental results available in the literature and demonstrated excellent agreement with the measured global response. A comprehensive parametric investigation was subsequently performed by considering two interface conditions (perfect bond and frictional contact), three axial load ratios, four interface friction coefficients, and different structural steel ratios under displacement-controlled cyclic loading. Structural performance was evaluated in terms of hysteretic response, lateral load capacity, stiffness degradation, and cumulative energy dissipation. The results indicate that the perfect bond assumption consistently overestimates the seismic performance of SRC columns by predicting higher lateral strength, greater stiffness, and significantly larger energy dissipation than the frictional interface model. Depending on the axial load ratio, the cumulative energy dissipation capacity of the frictional model was 44.2–73.1% lower than that of the perfect bond model, while the influence of interface modeling became increasingly pronounced at higher axial load levels. Increasing the interface friction coefficient enhanced the composite action between steel and concrete, although its influence on peak lateral resistance remained relatively limited. The findings demonstrate that realistic steel–concrete interface modeling is essential for reliable nonlinear finite element simulations and provides practical guidance for the seismic assessment and design of SRC columns. Full article

The yanglou buildings of Quanzhou are composite architectural heritage shaped by overseas Chinese and local traditions whose front facades provide an observable interface for comparing local and foreign cultural combinations. As existing studies emphasize plan typology and lack quantitative facade comparison, this study takes 40 yanglou buildings built by overseas Chinese between the late Qing dynasty and the 1960s in urban Quanzhou, Jinjiang, Shishi, and Nan’an and constructs a workflow of data survey, acculturation quantification, stage identification, and discriminative contribution analysis. The results show marked heterogeneity: the veranda presents strong object culture expressions, the wall elements are dominated by subject culture, and the hierarchy in the composition is unstable. FCM results show that the facades approximate continuous transitions rather than a single linear sequence. PLSR results show that the subject and object culture proportions in the veranda and wall elements and the object and renewal culture proportions in their compositions contribute more discriminatively to stage identification. This study shows that Quanzhou yanglou buildings are not direct transplantations of Western styles but composite heritage grounded in subject culture, absorbing object culture features and generating only limited renewal culture, providing a quantitative framework for stage identification, value interpretation, and differentiated conservation. Full article

Thermal pads are widely used for heat dissipation in electronic devices, but their performance can be limited by incomplete contact with the adjoining surfaces. In this study, a double-sided finger-joint interface was introduced to improve thermal contact without modifying the composition of the thermal pad. Two commercial thermal pads were assembled between either planar or finger-structured brass substrates and tested under pressures ranging from 0.1 to 1.0 MPa. For both pads, the finger-joint interface reduced the thermal contact resistance to approximately one-third of that measured with the corresponding planar interface. Surface morphology characterization and mechanical analysis indicated that the finger geometry increased the local normal contact force and promoted more effective contact between the pads and substrates. In a bolt-clamped LED assembly, the finger-joint interface reduced the chip temperature by 49.6 °C at 1.0 A, corresponding to a 45.3% reduction in chip temperature rise. This improvement was retained after 100 heating and cooling cycles. These findings demonstrate that surface geometry provides a practical approach for improving the effective thermal contact performance of thermal pads. Full article

Asymmetric heat transfer is an intrinsic and defining feature of phase change material (PCM) systems, arising from the nonlinear coupling between conduction, buoyancy-driven convection, interfacial motion, and geometric or operational non-uniformities. This review synthesizes the physical, numerical, and application-specific mechanisms through which asymmetry emerges and shapes the thermal behavior of PCM-based energy systems. We first examine the fundamental origins of asymmetry, highlighting how natural convection, material heterogeneity, and spatially uneven boundary conditions distort temperature fields and melt front evolution even in nominally symmetric enclosures. We then provide a comprehensive assessment of state-of-the-art modeling approaches—including full-domain CFD, advanced interface tracking methods, stability and bifurcation analysis, and reduced-order modeling—emphasizing their capacity to resolve asymmetric flow structures and capture the complex dynamics governing phase transition. Experimental observations from optical, infrared, and flow visualization techniques further validate the prevalence of asymmetric patterns and underscore the need for high-resolution multi-field datasets. Building upon these foundations, the review analyzes the implications of asymmetry across key energy applications such as thermal energy storage, building envelopes, solar receivers, electronics cooling, transportation systems, and industrial heat exchangers. We also provide a literature review on the importance of using multicriteria evaluation as a key tool in the design of multidimensional symmetric and asymmetric PCM systems. In this context, we address and analyze the performance criteria, evaluation metrics, case studies, and optimization strategies to be considered in the design of these systems. Finally, we identify critical research gaps—including multiphysics coupling, uncertainty quantification, CFD–machine learning integration, and the exploration of emerging asymmetric applications—and outline pathways toward next-generation PCM-based technologies that not only accommodate asymmetry but strategically exploit it for enhanced thermal performance. Full article

Effector proteins are key virulence factors of obligate parasitic fungi during infection. Wheat leaf rust by Puccinia triticina is a widespread destructive disease drastically limiting wheat production, while the biological role of its effector is still elusive. PtRTP1 is a homolog of Uf-RTP1p, one of the earliest effector proteins verified to localize at the host–pathogen interface. Clarifying PtRTP1 function helps uncover rust pathogenic mechanisms; hence, we cloned PtRTP1 from P. triticina. The gene has a 1453 bp DNA sequence and a 777 bp CDS, encoding a protein with a 23 aa signal peptide, nine cysteines and two N-glycosylation sites. PtRTP1 was differentially expressed during infection, peaking at 24 hpi. Its expression pattern was consistent across races, with higher levels in the highly virulent strain THTT. Analysis of the nucleotide-sequence polymorphism of PtRTP1 from nine physiological races of P. triticina revealed two polymorphic sites. Heterologous expression assays demonstrated that the PtRTP1 protein could suppress BAX-induced programmed cell death and functioned in the nucleus. Host-induced gene silencing revealed that silencing PtRTP1 weakened fungal pathogenicity, reducing pustules and infection areas in wheat lines TcLr15 and TcLr36. This indicates secreted PtRTP1 acts as a virulence factor. Full article

Emerging and novel ovine viruses pose increasing threats to animal health, livestock productivity, trade, food security, and public health preparedness. Their emergence is driven by complex interactions among animal movement, mixed-species production systems, wildlife–livestock interfaces, arthropod vectors, environmental changes, and viral evolution. This review critically compares current strategies for identifying major, emerging, re-emerging, zoonotic, and newly recognized ovine viruses, with emphasis on their analytical sensitivity, turnaround time, throughput, operational cost, accessibility, field applicability, validation status, and capacity for novel-virus detection. Conventional diagnostic approaches, including virus isolation, serology, antigen detection, histopathology, and immunohistochemistry, remain essential for confirmation and flock-level surveillance but may be limited by slow turnaround, dependence on specialized facilities, reduced sensitivity at low viral loads, and an inability to identify highly divergent or unknown viruses. Targeted molecular assays, including PCR, RT-PCR, qPCR, multiplex assays, digital PCR, isothermal amplification, and CRISPR-based diagnostics, have improved detection speed and sensitivity but generally require prior knowledge of viral genomic targets. Genomic and metagenomic approaches, including whole-genome sequencing, next-generation sequencing, nanopore sequencing, viral metagenomics, bioinformatics, and phylogenetic analysis, provide broader detection capabilities by enabling characterization of viral diversity, outbreak tracing, co-infection identification, and discovery of previously unrecognized viruses. However, their interpretation remains challenging due to low viral abundance, poor sample quality, host nucleic acid background, contamination, incomplete reference databases, limited computational capacity, and the inability of sequence detection alone to confirm disease causality. Therefore, future ovine virus surveillance requires integration of molecular diagnostics with active, passive, outbreak-based, risk-based, vector, wildlife, and animal-movement surveillance within a One Health framework. Linking genomic information with ecological, epidemiological, and environmental data will be essential for transforming ovine virus surveillance from reactive diagnosis toward proactive preparedness. Advances in standardized sampling, validated field diagnostics, affordable sequencing, curated databases, bioinformatics capacity, and cross-sector data sharing will strengthen early recognition, risk assessment, and preparedness against emerging viral threats in sheep. Full article