Search Results (1,216)

Silver-coated yarns, hook-and-loop fasteners, dry electrodes, and snap connectors are the most common means of establishing electrical contact in smart garments, owing to silver’s favorable conductivity, lower cost relative to gold, and compatibility with flexible fiber coatings. In practice, however, these components fail in a recurring pattern: the silver coating wears away or corrodes, and the electrical path is interrupted. This problem has, until now, been studied by separate research communities that rarely cite one another: tribology researchers have characterized how silver connectors wear under vibration, textile researchers have examined how they degrade during washing and sweat exposure, and coating researchers have investigated how the coating itself is applied. This review systematically maps evidence across these three strands of the literature and evaluates, pathway by pathway, the strength of support for each. Six degradation pathways are examined, namely vibration, repeated plugging and unplugging, laundering, sweat exposure, atmospheric exposure, and fiber or debris entrapment, and all six are found to be consistent with a single underlying mechanism: loss of the silver layer and a consequent reduction in working contact points, with three of these pathways, fretting, laundering, and perspiration corrosion, supported by direct measurement. One study further shows that short-term sweat exposure can transiently increase conductance before longer exposure reduces it, indicating that this degradation is not strictly a one-way process. The review also compares coating deposition methods and identifies a mitigation strategy proposed independently for two of the six pathways: adding a second conductive layer, such as carbon nanotubes or a thin gold overcoat, that remains functional after the underlying silver is depleted, although this strategy has not yet been cross-validated between pathways. Because nearly every study reviewed here tests only a single stressor at a time, with genuine combined-stress evidence limited to one study, this review argues that more realistic, combined-stress testing is still needed and proposes a concrete framework for such testing. Full article

Volatile organic compounds (VOCs) from coal-chemical enterprises pose a significant challenge to the environment and sustainability. Nevertheless, the fugitive VOC emissions from equipment and pipeline systems, and the application research of leak detection and repair (LDAR) technology within coal-chemical enterprises have received limited attention, impeding sustainable development goals. This study selected three representative coal-chemical enterprises to conduct large-scale LDAR surveys in 2022 and 2023. Based on field measurements exceeding 260,000 affected components per year, leak characteristics, emissions, and LDAR effectiveness were analyzed and evaluated from three aspects: enterprise-wide, process-specific, and component-level. The one-way analysis of variance revealed no statistically significant differences in overall leak concentrations between enterprises, whereas significant differences between component types. Non-flanged connectors had a higher leak level, followed by open-ended lines, pumps, valves, and flanges. The process-specific leak ratios (0.29~1.71%) and emission contributions (9.33~35.31%) were highest in downstream units, whereas leak ratios (0.05~0.08%) and emission contributions (0.75~10.57%) were lowest in midstream and upstream units, respectively. The component-level ratios were pronounced for open-ended lines (1.84%) and valves (0.79%), while emissions were primarily concentrated on flanges, non-flanged connectors, and valves (96.1~99.1%). The repair ratios (87.42%, 90.88%), emission reduction rates (58.56%, 60.45%) under restorations, and decreases in leak ratios (44.59%) and emissions (33.22%) over consecutive years comprehensively identified the LDAR effectiveness. Finally, the precise control and policy implications were discussed accordingly. These findings aimed to provide basic references for coal-chemical enterprises in precise control and sustainability policies. Full article

This study evaluates a route in which a humidity-cured epoxy is applied to a cleaned steel surface and concrete is cast directly onto the still-tacky adhesive, eliminating welding and pre-drying. As a preliminary study, six push-out specimens in three configurations—studs only (G1), pure bonding (G2), and studs combined with bonding (G3)—were tested under monotonic load control, with two specimens loaded statically in each group. Mean ultimate capacities were 474.5, 680 and 720 kN for G1, G2 and G3. Bonded specimens failed within the concrete matrix, leaving concrete on the steel plate and indicating that the wet-cast bond line exceeded the near-surface strength of the concrete. Interface slip in G2 and G3 remained below the measurement resolution (±0.001 mm), consistent with elastic shear of the 1–2 mm epoxy layer. Concrete strains remained compressive throughout loading in bonded specimens, whereas stud specimens developed bottom-surface tensile strains of about 220 με, indicating that discrete connectors induce a local bending field that continuous bonding removes. However, bonded failure was abrupt and non-ductile; the hybrid configuration retained a post-debonding load path that provided a residual capacity of about 68% of the stud-only residual (reconstructed numerically in “Finite Element Verification”), converting a brittle mechanism into one with a secondary, damage-tolerant reserve. Full article

Inter-modular connections (IMCs) govern the structural performance, safety, seismic resilience, and reusability of steel modular buildings, yet the existing literature on advanced IMC systems remains fragmented and connection-specific. This paper presents a comparative review of nine research-stage advanced steel IMC systems benchmarked against VectorBloc, the only commercially deployed proprietary connector among the systems considered, selected through a transparent screening of 120 research articles drawn from Scopus, Web of Science, ScienceDirect, and Google Scholar, of which 60 were retained for detailed analysis based on predefined inclusion and exclusion criteria. The ten connections reviewed are the VectorBloc Registration Pin (commercial benchmark), friction rocking, Shape Memory Alloy (SMA) Bolt, Cruciform Plug-in, L-Shaped Bracket with Web Cut-Outs, H-Shaped Bracket, Mid-Depth Self-Locking Plug-in, corrugated web moment frame, post-tensioned rod with friction washer, and Omnidirectional Through-Plate Corner connections. As VectorBloc is a commercially available proprietary product rather than a research-stage connection, it is not directly compared with the other nine systems in this review; it is included solely to provide a qualitative commercial point of reference. Each of the nine research-stage systems are assessed on a like-for-like basis against eight criteria: structural capacity, seismic response, energy dissipation, fire performance, constructability, sustainability, reusability, and cost impact; VectorBloc is discussed against these same criteria qualitatively, as a reference point for current commercial practice, rather than ranked numerically alongside the nine. The comparison shows that SMA bolts and friction rocking connections excel in seismic resilience and self-centring, corrugated web connectors combine high energy dissipation with sustainability benefits, and VectorBloc’s commercial track record offers a useful benchmark for constructability and cost efficiency, although no single system performs best across all criteria. A multi-criteria design framework is proposed to guide future connection development and hybrid strategies, identifying fire performance, long-term durability, and reusability as the most significant research gaps for next-generation modular steel buildings. Full article

Recent autonomous exploration systems for unmanned platforms have improved motion efficiency, trajectory smoothness, and replanning continuity, but thorough coverage remains difficult in confined environments with short branches and partially resolved connectors. We present TOVEX, a completion-oriented framework that couples unresolved Euclidean signed distance field (ESDF) voxels with a sparse topological voxel-sphere (TVS) graph. Evaluation includes a bridge simulation, five-run maze comparisons with the baseline systems EDEN, GBPlanner, and TARE, component ablation, runtime and memory profiling, a cross-structure cave-scene stress test, and real-world experiments with an unmanned aerial vehicle (UAV) in an underground garage and an unmanned ground vehicle (UGV) in a warehouse. The bridge test shows coherent mapping and continuous velocity profiles. In the maze, TOVEX achieves the highest median final coverage of 96.2%, exceeding TARE by 5.2 percentage points, while TARE remains stronger in early coverage and motion efficiency. The geometry-derived terminal-tail analysis confirms that TOVEX achieves the most complete residual-passage resolution, while removing short-branch priority produces the largest loss. At approximately 1100 TVS vertices, median target-selection latency is 0.89 ms and planner proportional set size (PSS) is 52.3 MiB. Field trials demonstrate the same gain-bearing decision layer on aerial and ground platforms. TOVEX is well suited to unmanned-platform missions that prioritize resolving accessible residual passages. Full article

Visitors encounter museums through movement, as galleries, routes, and levels become visible and accessible from successive bodily positions. Yet, stair approaches, landings, balconies, and gallery thresholds are often treated as residual connectors rather than as spaces that help stage museum sequences. This study examines that role through eight selected liminal conditions at Steven Holl’s Kiasma Museum of Contemporary Art, Helsinki: four spiral-linked spaces, two atrium balconies, and two gallery thresholds. Grounded in embodied, ecological, and enactive accounts of perception, the study analysed eight paths using sequential isovist profiles interpreted alongside plans, sections, and observations. The transitions reorganise visibility and locomotor access in distinct ways along the route rather than sharing a common metric pattern. Spiral-linked spaces relate local movement to a recurring vertical circulation system, balconies provide visual relations across levels while withholding direct movement between them, and gallery thresholds withdraw one gallery setting and establish another progressively or abruptly. These findings show that spaces commonly treated as circulation can prepare, connect, separate, withdraw, and disclose successive museum settings. Sequential isovist analysis describes how this configurational work unfolds, specifying permanent environmental conditions relevant to embodied spatial cognition and to museum and exhibition sequencing, without taking geometry as evidence of experience or curatorial intention. Full article

To mitigate performance degradation caused by variations in host-platform ground configurations, this paper presents a compact wideband printed antenna for Wi-Fi 6E and Wi-Fi 7 applications. Occupying an ultra-miniature footprint of only 18 × 15 mm², the proposed antenna consists of an asymmetric T-shaped monopole (ATM), an open stub, and a meandered loop ground-line structure. The meandered ground line operates as a modified planar sleeve balun to reduce PCB-induced common-mode current propagation and improve robustness against representative host–ground variations. By controlling the electromagnetic coupling between the ATM radiator and the meandered ground loop, broadband impedance matching is achieved without additional matching circuits. The proposed antenna covers three operating bands: 2.4 to 2.5 GHz, 5.15 to 5.85 GHz, and 5.925 to 7.125 GHz. Measurement results demonstrate stable resonant frequencies and wide impedance bandwidths across the investigated host–ground configurations, with measured radiation efficiencies up to 88% at the investigated frequencies. The measured radiation patterns exhibit quasi-omnidirectional characteristics at 2.45 GHz, while multilobe behavior becomes more pronounced at 5.5 and 6.5 GHz due to higher-order modes associated with the meandered ground loop. A quantitative coverage-efficiency or minimum-realized-gain analysis is beyond the scope of this study. Although demonstrated using a USB wireless adapter, the proposed operating mechanism is associated with the antenna structure rather than the USB connector itself. Full article

Background/Objectives: Antimicrobial resistance (AMR) and virulence represent co-evolving dimensions of microbial pathogenic potential whose ecological organization in building-scale wastewater systems remains poorly understood. Methods: Using shotgun metagenomic sequencing, we characterized the temporal dynamics and ecological associations of antimicrobial resistance genes (ARGs) and virulence factors (VFs) in 12 wastewater grab samples (2 per semester) collected from a university residence hall designated for COVID-19 quarantine between 2021 and 2023. Results: The wastewater microbiome was anchored by a stable core of gut-associated anaerobic bacteria, with community composition exhibiting significant Spring-versus-Fall structuring and a year × semester interaction that explained 60% of the community variation. A marked shift toward opportunistic taxa, particularly Acinetobacter, during Fall 2023 represented the most pronounced temporal perturbation. Total ARG abundance remained stable across semesters, while resistome composition shifted significantly, indicating that temporal dynamics were driven by compositional turnover rather than changes in overall resistance burden. VF functional categories were broadly conserved across sampling periods, consistent with their structural embedding within the persistent fecal core microbiome. Correlation and network analyses revealed modular ecological coupling between resistance and virulence functional categories, with metal/co-resistance and fosfomycin classes showing the strongest associations with virulence functions. At the community level, a Benjamini–Hochberg–corrected co-occurrence network resolved into taxa-anchored resistance modules and separate virulence-function clusters, with Acinetobacter and fluoroquinolone resistance as the principal connectors. Conclusions: These findings indicate that building-scale wastewater metagenomics can capture ecologically structured functional gene dynamics, highlighting its potential as a surveillance tool for monitoring AMR and virulence in built environments. Full article

The effects of wide-ranging service temperatures on interfacial bond transfer and slip evolution in high-strength concrete-filled steel tube members have not yet been systematically characterized. A test program involving 15 circular specimens was carried out at temperatures between −60 °C and 60 °C with steel tube wall thicknesses of 2 mm, 3 mm, and 4 mm. Particular attention was given to interface failure patterns, slip development, and stress transfer during loading. Cooling markedly enhanced the interfacial resistance, whereas heating produced a moderate reduction. The increase observed at subzero temperatures was smaller than that commonly reported for conventional concrete-filled steel tubes. Bond capacity also declined as the diameter-to-thickness ratio increased because of reduced confinement from the steel tube. Regression of the experimental data produced expressions for ultimate bond strength and the associated slip. A piecewise constitutive relation was then formulated to represent the complete bond–slip process. The proposed relation was implemented in ABAQUS through distributed nonlinear connector elements and temperature-dependent material properties. Numerical predictions showed close agreement with the measured load–slip responses, characteristic loads, and stress distributions. These results provide a modeling basis for HSCFST members exposed to severe cold and large temperature fluctuations. Full article

Corrosion-severity grading of grounding-grid connectors from optical images supports proactive power-infrastructure maintenance. Existing approaches rely on single-time-point, manually thresholded hue–saturation–value (HSV) metrics and static multi-criteria decision-making (MCDM) frameworks that cannot capture corrosion dynamics. In this paper we present a pipeline that (1) defines a four-class corrosion grade from an HSV area fraction (S_corr) measured on RGBA optical images, and validates those labels against a baseline-referenced CIEDE2000 metric zero-referenced to each connector’s as-received appearance; (2) generates 240 color-prior-constrained procedural synthetic images from 53 real images across six connector types; (3) fine-tunes a ResNet-18 to estimate corrosion coverage continuously, deriving the reported severity class from that estimate rather than predicting it directly; and (4) fits power-law kinetics C(t) = k·tⁿ to the S_corr time series, propagates bootstrap uncertainty into a Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) framework, and reports kinetics-aware rankings as rank probabilities. The label validation quantifies two limitations of single-threshold HSV grading: a material-color offset that scores an unexposed copper connector at S_corr = 0.442, and insensitivity to achromatic corrosion products covering roughly 80% of the aluminum and galvanized-steel surface. Ablation experiments replicated over five random seeds show that neither contribution claimed from a single run survives replication: synthetic augmentation changes macro-F1 by +0.050 (p = 0.46) under the adopted checkpoint-selection rule and by −0.059 (p = 0.43) under the rule used in the original experiments, and the monotonicity-consistency loss by −0.011 (p = 0.87) and +0.001 (p = 0.99) respectively; the previously reported single-run values of 0.208 and 0.494 are draws from opposite tails of the same seed distributions (0.403 ± 0.140 and 0.344 ± 0.073). The one formulation that improves significantly is the continuous one adopted here, which raises Spearman agreement with the independent metric from 0.316 ± 0.150 to 0.698 ± 0.108 (p = 0.005). Measured against controls, a classifier that never sees the image reaches macro-F1 = 0.425 and, after Holm–Bonferroni correction, no deep configuration is distinguishable from it; none exceeds a one-dimensional linear rule on S_corr (0.664); and under leave-one-material-out cross-validation the network does not improve on S_corr used directly as a predictor (ρ = +0.627 against +0.744, paired p = 0.14). Time-resolved energy-dispersive X-ray spectroscopy (EDS) provides a partial chemical consistency check, with welding at ρ = 0.82 (raw p = 0.023), but no material survives Holm correction across the six tested. A U-Net segmentation head supervised only by synthesis-derived masks attains Dice = 0.85 in-domain and collapses to a 0.033 output range on real images, 5% of the HSV metric’s range; the photometric-stability advantage previously claimed for it is an artifact of that collapse and is withdrawn. Kinetics-aware MCDM with propagated uncertainty resolves 9 of 15 pairwise orderings, placing stainless steel above welding at 30 chamber days with probability 1.000 and reversing the static ranking. The pipeline, code and fixed data split are fully reproducible (random seed 42). Full article

The frequency-dependent impedance of electrical connectors, switchgear loops, and related contact structures can indicate degradation at electrical contact interfaces. Conventional contact measurements with a vector network analyzer require dedicated adapters and impedance matching, and the object under test usually has to be removed from the operating system. To simplify field measurements and avoid direct electrical contact, this study employs an established two-probe inductive-coupling/ABCD de-embedding framework in conjunction with a purpose-designed broadband current probe and calibration fixture. Commercial injection and receiving probes were first evaluated to identify practical limitations associated with probe resonance, magnetic-path air gaps, cable clamping, and probe-to-probe coupling. A parametric CST study on ferrite material, winding turns, and core geometry was then used to select a 3W800 NiZn ferrite core with six winding turns and dimensions of 5 mm inner diameter, 10 mm outer diameter, and 5 mm height. The prototype exhibited relatively flat S₁₂/S₂₁ responses from 1 to 400 MHz, with S₂₁ changing from approximately −13.5 dB at 1 MHz to −17.5 dB at 400 MHz and without a pronounced resonance. Quantitative impedance accuracy was validated only over 1–100 MHz: validation against an impedance analyzer using a 108 nH inductor and an 82 pF capacitor yielded mean relative magnitude errors of 4.00% and 4.5%, respectively. Field measurements on a 10 kV switchgear circuit were additionally conducted over 1–30 MHz to demonstrate non-invasive broadband impedance acquisition under practical contact conditions. Accordingly, the 1–400 MHz range in this work refers to probe-transfer characterization rather than experimentally validated impedance accuracy over the full band. Full article

Steel moment-resisting frames are widely used in seismic regions, but conventional beam–column connections often suffer from concentrated damage and difficult post-earthquake repair. To address these issues, this study proposes a novel replaceable energy-dissipating slit beam–column joint for steel frames. To enhance structural energy dissipation efficiency, mitigate seismic damage, and enable rapid post-earthquake repair, the joint utilizes connectors as energy-dissipating elements such that plastic deformation is confined to these connectors while main beams and columns remain elastic throughout the loading history. A quasi-static test was conducted on the proposed joint. The test results indicate that the hysteresis loops are full and fusiform, demonstrating excellent energy dissipation capacity. The joint exhibits ductility coefficients of 6.30 and 5.27 under positive and negative loading, respectively, and the equivalent viscous damping coefficient remains above 0.30 after a rotation of 0.025 rad. Furthermore, plastic damage is primarily sustained by the connectors, with no evident yielding observed in other structural members. To further investigate the joint, it was applied to a three-story, four-bay, three-span steel frame for finite element analyses. Compared with a conventional rigid joint frame, the proposed joint frame under rare earthquakes reduces roof displacements by 20.97% (with the X-direction as the primary direction) and 16.23% (with the Y-direction as the primary direction), and maximum interstory drift ratios by 18.06% (with the X-direction as the primary direction) and 15.55% (with the Y-direction as the primary direction), while satisfying the code-specified limits of 1/250 for elastic and 1/50 for elastoplastic interstory drift ratios, thereby indicating its superior seismic performance. Full article

High-strength steel–ultra-high-performance concrete (UHPC) composite beams provide an efficient solution for lightweight and high-capacity building structures. This study presents a preliminary experimental investigation on the flexural behavior of three high-strength castellated steel–UHPC composite beam configurations employing hinged-bolt shear connectors. This connector type had previously been validated only at the component level and was applied here for the first time in high-strength castellated steel–UHPC composite beams. The three beams were tested under positive bending: a reference specimen with a full-depth cast-in-place UHPC slab and dispersed connectors (CC-DHB), a prefabricated specimen with a C100 precast slab, dispersed connectors, and local UHPC connection regions (PC-DHB), and a prefabricated specimen with a C100 precast slab, grouped connectors, and local UHPC connection regions (PC-GHB). The failure mode, load–deflection response, ductility, interface slip, strain distribution, and flexural resistance were evaluated. The results showed that all specimens exhibited flexure-dominated failure, characterized by the yielding of the steel girder and tensile reinforcement occurring first, followed by concrete crushing near the loading region. A key finding was that, although UHPC was used only in the local connection regions of the two prefabricated configurations, their peak flexural resistances were only 4.5% and 2.5% lower than that of the full-depth cast-in-place UHPC reference beam, indicating that the prefabricated beams substantially reduced UHPC use while retaining nearly the same ultimate flexural resistance as the reference beam. However, their initial stiffness and ductility factors decreased by up to 17%, while their cracking load decreased by approximately 50%. Compared with specimen PC-GHB, the initial stiffness and ductility of specimen PC-DHB increased by approximately 5%. The maximum measured interface slip before the peak load was less than 3 mm for all specimens. A preliminary sectional plastic-resistance method was also developed, and the calculated-to-tested resistance ratios ranged from 1.06 to 1.08. Further validation is required for different connector spacings, web-opening layouts, slab configurations, and shear connection degrees. Full article

Background: Polypharmacy remains a significant challenge, often leading to adverse drug events and increased healthcare costs. One effective strategy to mitigate these risks is deprescribing, the systematic and intentional discontinuation or reduction of medications. Despite growing recognition of deprescribing’s importance, limited research has examined the impact of interprofessional education interventions on developing deprescribing competencies among healthcare professional students. This study aims to examine the perspectives of healthcare students, including student pharmacists, medical students, and nurse practitioner students, regarding their roles and responsibilities in the deprescribing process. Methods: Following completion of a Deprescribing Interprofessional Education Simulation activity (DIPE-SA), participants were invited to join focus groups. The study included students from the University of Tennessee Health Science Center (UTHSC) Colleges of Medicine, Nursing, and Pharmacy. Constructivist Grounded Theory (CGT) underpinned the qualitative research approach, informing the development of the study framework. Each focus group was facilitated by two researchers and recorded. Recruitment continued until saturation was achieved. Data were transcribed verbatim and analyzed for themes using Dedoose, qualitative analysis software. Results: A total of 19 participants attended four focus groups. Three major themes emerged and guided the development of the Roles–Collaboration–Communication (RCC) interprofessional framework. The first theme, roles, focuses on the unique responsibilities and functions healthcare professionals assume within the team and throughout the deprescribing process. The second theme, collaboration, emphasizes coordinated efforts and shared decision-making among members of the interprofessional healthcare team in deprescribing. Finally, the third theme, communication, highlights the importance of effective information and intention exchange, serving as both a mediator and connector, linking roles and collaboration, and ultimately enabling successful deprescribing. Conclusions: This study’s findings, together with the RCC interprofessional framework, demonstrate the interplay of roles, collaboration, and communication in medication management. The RCC framework highlights the value of dynamic team processes for achieving safe and effective deprescribing, which in turn improves patient care and health outcomes. Full article

Structural design codes provide safe procedures for verifying steel–concrete composite beams but do not directly guide engineers toward cost-effective configurations. This study aims to develop and evaluate a surrogate-assisted framework that combines a Multilayer Perceptron neural network with Bayesian Optimization for the preliminary flexural-resistance and material-cost optimization of simply supported steel–concrete composite beams designed according to the Brazilian code NBR 8800. A dataset containing 20,000 beam configurations and 15 input variables was generated using a Python-based analytical routine that implements the NBR 8800 provisions for the positive bending resistance of composite beams. The generated dataset was used to train a Multilayer Perceptron neural network to predict the design bending resistance. The trained surrogate model was then integrated with Bayesian Optimization to search a discrete design space comprising commercial steel profiles, concrete slab thicknesses, shear connector quantities, and connector diameters. The selected neural network architecture achieved validation MAE and RMSE values of 2.128 kN·m and 3.013 kN·m, respectively, with an $R^2$ of 0.9999. In ten benchmark scenarios, the BO–MLP framework identified candidate solutions using only 60 objective-function evaluations. This corresponds to 3% of the evaluation budget adopted for GA and PSO and approximately 0.057% of the configurations examined by exhaustive search. Despite this limited sampling budget, the resulting candidate solutions presented an average optimality gap of approximately 12.1% relative to the global reference. In computational terms, GA and PSO required approximately 4.1 and 4.9 times the execution time of BO–MLP, respectively, while exhaustive search required approximately 18.4 times the execution time. Overall, the proposed framework offers a computationally efficient means of exploring discrete composite-beam configurations and identifying cost-competitive candidate solutions. Direct NBR 8800 verification showed that seven of the ten selected candidates satisfied the resistance requirement, while three presented resistance-to-demand ratios slightly below unity. Therefore, the framework should be used as a preliminary screening tool, with the selected configurations subsequently verified using the complete code-based procedure. Within the restricted structural domain investigated, the framework can support preliminary decisions related to positive bending resistance and material cost. Full article