Search Results (1,936)

Vision-based hand gesture recognition (HGR) systems are predominantly developed for frontal camera viewpoints, whereas smart-home cameras are often ceiling-mounted, creating a viewpoint-induced domain gap. To investigate this issue, we collected and manually annotated CeilGest, an 18-class ceiling-view hand gesture dataset comprising 156,282 annotated frames from 68 participants recorded in distinct domestic environments. We then systematically evaluated frontal-to-ceiling transfer using YOLO-based detectors trained on HaGRID and compared their performance with an in-domain CeilGest-trained model. On identical ceiling-view footage, the frontal-trained YOLOv8n produced approximately 24× more class-to-class misclassified frames than the in-domain model (486 vs. 20 across 27,000 frames); this large paired difference remained evident when temporal dependence within gesture holds was taken into account. The effect was strongly class-dependent, with AP decreasing by up to 5.5 percentage points for the worst-affected gesture, while the aggregate same-architecture mAP50 difference was 0.6 percentage points. Across five YOLOv8 variants evaluated on frontal HaGRID, mAP50 remained at 0.995, supporting selection of the lightweight YOLOv8n for edge deployment. The complete ceiling-view HGR pipeline was implemented on Raspberry Pi 5 using NCNN and Jetson Orin Nano using TensorRT. Mean inference latency was 74.69 ± 4.72 ms and 12.72 ± 0.12 ms, respectively. During a 10 min continuous Raspberry Pi 5 test, mean inference latency increased by 17.6% and junction temperature reached 90.8 ${}^{\circ }$C with thermal throttling. Power consumption and INT8 inference were not evaluated. Overall, the results show that training–deployment viewpoint consistency is a major consideration for ceiling-mounted HGR and establish an in-domain supervised baseline relative to frontal-only training without domain adaptation. Full article

Simulation studies of surplus electricity in sugarcane cogeneration almost universally assume stable nominal operation, and the sector literature qualitatively acknowledges that many surplus projects underperform; however, this discrepancy has not been systematically quantified against multiyear operational records. Using daily records from seven harvest seasons (2010–2016; 931 valid days) of a Cuban low-pressure sugar mill and the previously published simulation of its own thermal scheme (Termoazúcar STA 4.1), this study quantifies the discrepancy through the Energy Performance Gap (EPG) framework adapted from building science. The export shortfall relative to the simulated baseline ranged from 19.0% to 49.3% per harvest (38.1% aggregated over 2010–2015; 12,835 MWh unrealized) and reached 28.9% for the five-mill provincial aggregate. The gap does not arise from idle capacity—availability is 0.98–1.00, and industrial demand matches the simulated value—but from conversion, with a cane-weighted generation deficit of 5.46 kWh/t ($-12.7$%). Plant steam records proved to be accounting allocations based on fixed coefficients and cannot support correlation-based inference; what they document independently is a contiguous start-of-season regime with pressure-reducing valves in service (39 days of a single harvest), during which specific generation was 11.9 kWh/t lower at statistically identical milling rates (26.15 vs. 38.06 kWh/t; $p<0.001$). No interannual trend was detected (Mann–Kendall, $p=0.368$), although statistical power is limited, at $n=7$. A Monte Carlo characterization of the parametric uncertainty of the simulated baseline (boiler efficiency $\pm 3$%, turbine isentropic efficiency $\pm 5$%, and bagasse moisture $\pm 2$ percentage points) shows that the existence of the gap is robust—the probability of no gap is, at most, 1.1%, even under worst-case uniform perturbations—while widening the intensity-level discount interval to [0.57; 0.93]; a start-of-season depression in specific generation recurs in four of the six estimable harvests, of which the 2015 reducer regime is the most severe instance. As case-specific correction tools, operational discount factors of 0.71 (95% block-bootstrap CI [0.68; 0.75]) for export intensity and 0.62 for total seasonal energy are derived; the underlying procedure, rather than the numerical values, is proposed as transferable. Full article

The substitution of conventional materials with alternative resources is a significant approach for enhancing the engineering performance and sustainability of foamed concrete (FC). While supplementary cementitious materials, volcanic materials, and waste-derived materials have been extensively investigated, the use of obsidian as an alternative aggregate in FC systems remains largely unexplored, and the combined, systematic comparative use of obsidian, waste ceramic powder (WCP), and recycled concrete powder (RCP) within a unified experimental framework has not been previously investigated. This paper evaluates the use of obsidian, WCP, and RCP as alternative aggregates in hydroxypropyl methylcellulose (HPMC)-stabilized FC by replacing standard sand at 25%, 50%, and 100% levels. The thermal, durability and mechanical characteristics of the mixtures were assessed through density, compressive strength (CS), ultrasonic pulse velocity (UPV), water absorption (WA), elevated temperature resistance (200 °C, 400 °C, 600 °C and 800 °C), freeze–thaw performance, thermal conductivity (TC), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS) and X-ray diffraction (XRD) analyses. The results showed that the 28-day CS increased from 0.545 MPa in the control mixture to a maximum value of 2.590 MPa in the obsidian-based FC. Moreover, WA decreased markedly from 117.7% to 46.9% in the obsidian-based FC. The UPV varied from 1355 to 1795 m/s due to the incorporation of RCP, WCP and obsidian at different replacement ratios in the mixture designs. The lowest TC of 0.08185 W/(m·K) was recorded in the obsidian-based FC at 50% substitution level. Under elevated-temperature exposure, the mixture with 100% obsidian replacement retained a compressive strength of 0.5936 MPa at 800 °C. To conclude, the use of obsidian, WCP and RCP as alternative aggregates in FC shows promising potential for the development of durable, thermally efficient, and sustainable lightweight construction materials. Full article

A series of polyurethane (PU) nanocomposites incorporating 4,4′-bis(hydroxymethyl)-2,2′-bipyridine (BBD) as a chain extender and a commercially supplied graphene/zinc oxide (G/ZnO) hybrid filler were successfully synthesized. The effects of G/ZnO loading (0–2.0 wt.%) on the structural, thermal, mechanical, surface-wettability, and antibacterial properties of the nanocomposites were systematically investigated. Fourier-transform infrared spectroscopy confirmed the formation of the polyurethane structure and revealed changes in characteristic absorption bands following G/ZnO incorporation. Morphological observation of the pristine G/ZnO hybrid filler revealed an irregular and aggregated morphology, while X-ray diffraction confirmed the presence of crystalline ZnO. Energy-dispersive X-ray spectroscopy and elemental mapping showed Zn-containing regions within the examined areas of the G/ZnO-containing PU samples. X-ray photoelectron spectroscopy further confirmed the surface presence of Zn-containing species, with the Zn atomic concentration increasing from 0 at.% in PU-01 to 0.82 at.% in PU-04. Thermogravimetric analysis showed modest changes in thermal decomposition behavior with increasing G/ZnO loading, while differential scanning calorimetry and dynamic mechanical analysis revealed shifts in glass-transition and relaxation behavior, consistent with changes in polymer-chain mobility and the local interfacial environment. The tensile strength increased from 2.68 MPa for neat PU to 11.76 MPa for the nanocomposite containing 2.0 wt.% G/ZnO, accompanied by an increase in Young’s modulus. The water contact angle increased from approximately 68° to 89°, indicating reduced apparent surface wettability with increasing G/ZnO loading. The nanocomposites also exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus, with antibacterial efficiencies exceeding 95% at higher G/ZnO loadings. Overall, the incorporation of the commercial G/ZnO hybrid filler was associated with changes in the thermal, mechanical, surface, and antibacterial properties of the BBD-containing PU system. Because separate PU systems without BBD and individual graphene- and ZnO-containing controls were not included, the individual contributions of BBD, graphene, and ZnO, as well as any synergistic effect between graphene and ZnO, cannot be established from the present results. Further studies addressing filler leaching, long-term antibacterial stability, coating adhesion, environmental durability, and cytocompatibility are required to establish the practical applicability of these materials. Full article

Accurate daily forecasts of thermal generation, renewable generation, hydropower, and imported electricity are essential for spot-market trading and day-ahead scheduling. However, short training histories, incomplete operational information, and distinct target drivers constrain accuracy and generalizability. To address these challenges, this study proposes a Delta-enhanced, validation-guided framework for configuring target-specific forecasting pathways. The Delta representation captures inter-day changes in thermal and hydropower generation. For the internal renewable-generation target, a regional target-day weather-forecast interface is applied retrospectively. It aggregates 13 hierarchical regional forecast columns for each of 24 weather variables and incorporates six calendar variables. For each target, chronological validation selects an admissible pathway defined by forecast-origin information, target representation, predictor family, optional temporal representation, and output rule. Once selected, it is refitted and fixed for subsequent forecasting. The evaluation covers four internal targets from a regional power system in China and six national-scale targets from France. The 97-day evaluation yielded R² values of 0.8084, 0.7337, 0.7782, and 0.5212 for thermal generation, renewable generation, hydropower, and imported electricity, respectively. The frozen thermal and renewable pathways reduced RMSE by 23.2% and 50.9%, respectively, relative to Persistence, a baseline that carries the previous-day value forward. These findings support target-specific forecasting under data constraints. Full article

Continuous thermal monitoring of aluminum electrolysis cells—which operate at ~950 °C under strong magnetic fields in a corrosive fluoride melt—remains an unsolved process monitoring challenge. This paper presents a fiber-optic Raman distributed temperature sensing (DTS) deployment for high-temperature cathode steel bar monitoring in a 380 kA industrial cell supplied by a grid with over 30% wind and solar penetration. A custom fiber ring packaging scheme, pressed against the underside of the cathode bar (temperature > 300 °C), achieved >1 m thermal contact length within the confined space beneath the cell. Features encoding supply-side renewable power periodicity, thermal inertia, and local fluctuation intensity were engineered to anchor the learning task in the process physics of the electrolysis cell. CatBoost, LightGBM, and Random Forest were combined in a stacking ensemble with a linear regression meta-learner, attaining RMSE = 0.7451 °C and R2 = 0.9944 over two months of continuous industrial operation across seven cathode bars. Frequency-domain residual decomposition revealed why LightGBM—the aggregate-weakest base learner—received the dominant meta-learner weight (+2.15) while CatBoost—the aggregate-strongest—received a negative weight (−1.85): LightGBM uniquely minimized high-frequency error (1.06 vs. 1.29 °C for CatBoost). The ensemble advantage was spatially robust across all seven bars. The 0.75 °C RMSE establishes a noise floor for residual-based monitoring, demonstrating that process-informed feature engineering and frequency-resolved stacking ensemble learning deliver predictive accuracy suitable as a process monitoring baseline in high-temperature industrial environments under increasing renewable power penetration. Full article

This study investigates metakaolin-based geopolymer recycled mortar (GRM) in which recycled fine aggregate (RFA) was volumetrically replaced by pumice powder (PP) at 0% and 60–100%. Ambient compressive and tensile bond strengths were measured, followed by exposure to 600–800 °C for 1–3 h. The evaluation encompassed mass loss ratio, residual mechanical properties, temperature sensitivity, micro-phase evolution, and strength-normalized carbon intensity. Results demonstrated that PP replacement produced a non-monotonic response, governed by the trade-off between improved particle packing and the depletion of the rigid granular skeleton. Among the PP-containing mixtures, PP₇₀ (70% replacement) showed a comparatively favorable mechanical response, with an ambient compressive strength of 31.7 MPa and a mean residual compressive strength of 18.8 MPa (59.3% of its initial value) after exposure to 800 °C for 3 h. Notably, tensile bond strength exhibited greater temperature sensitivity than compressive strength, with deterioration accelerating significantly above 700 °C. SEM and XRD analyses elucidated this macroscopic divergence via a two-stage damage mechanism: while dehydration and matrix contraction dominated at 600 °C, prolonged exposure at 800 °C induced structural rearrangement, with the dominant damage becoming increasingly concentrated at the RFA–matrix interface. Although substituting RFA with processed PP inherently increased the absolute embodied carbon, PP₇₀ exhibited the lowest strength-normalized carbon intensity among the modified mixtures after exposure to 800 °C for 3 h. These findings indicate that, among the investigated high-volume PP mixtures, PP₇₀ provided a comparatively favorable compromise between thermal-mechanical performance and environmental cost. Full article

While the individual effects of sustainable fillers on cementitious systems are widely known, their combined tribological and fracture behaviors within a polymer concrete matrix remain largely unexplored. Addressing this gap, this study experimentally investigates the physical, mechanical, and tribological characteristics of polyester-based polymer concrete (PC). In addition to reference specimens produced with polyester resin and silica sand, modified mixtures were developed by replacing the silica sand with ground granulated blast-furnace slag (GGBS) and recycled waste concrete aggregate (WC) at various substitution ratios (0%, 5%, 10%, 15%, 20%, and 25%). To evaluate the performance of the developed PCs, parameters including unit weight, water absorption capacity, flexural and compressive strengths, Shore D hardness, surface roughness, acid resistance, Bohme abrasion resistance, and fracture energy were analyzed. Furthermore, temperature variations on the friction surfaces were monitored in real time using a thermal camera during the Bohme abrasion tests. To elucidate the fracture mechanisms, the fractured surfaces were examined via digital microscopy. The quantitative findings indicate that a 25% GGBS replacement optimizes mechanical performance, increasing the compressive and flexural strengths by 21.2% (108.30 MPa) and 30.6% (35.29 MPa), respectively, alongside a 27% improvement in Bohme abrasion resistance. However, this modification significantly increases material brittleness, reducing the fracture energy by 53.3% compared to the reference. Conversely, although incorporating WC offers sustainability advantages, it limits mechanical performance, leading to decreases of up to 9.9% (80.46 MPa) in compressive strength and 15% (22.97 MPa) in flexural strength at a 20% substitution rate. Regarding fracture energy, while the W20 series absorbed more energy than the B25 series, it still remained 47.8% lower than the reference. Additionally, the GGBS-incorporated series demonstrated higher susceptibility to sulfuric acid attack compared to the WC-incorporated series. Full article

The use of phase change materials (PCMs) in cementitious mortars is a promising strategy for passive thermal regulation and thermal energy storage (TES) in buildings, but its practical implementation remains constrained by PCM leakage and its effects on physical and mechanical performance. This study investigates the use of recycled clay brick waste as a dual-function component in eco-efficient mortars, serving as a partial replacement for fine aggregate and as a porous carrier for paraffin-based PCM. The experimental program comprised three stages: selection of an eco-efficient reference mortar, impregnation of recycled ceramic aggregates using thermal and vacuum-assisted procedures, and evaluation of PCM-modified mortars through fresh-state, physical, mechanical, thermophysical, direct thermal exposure, thermoregulation, and infrared thermography tests. Thermal impregnation at 15 wt% PCM provided the most favorable balance between PCM incorporation and stability against surface accumulation and mass loss and was selected for mortar production. Compared with REFeco, PCM incorporation reduced water absorption by approximately 10% and caused compressive and flexural strength losses below 10%. PCM15 exhibited the most favorable thermophysical balance, increasing volumetric specific heat by 14.9% and thermal inertia by 8.5%, while reducing thermal diffusivity by 10.8%. Under direct flame exposure, PCM25 produced the greatest thermal buffering effect, delaying the attainment of 200 °C on the rear face by approximately 4 min and reducing maximum estimated heat flux by approximately 16% relative to REFeco. Overall, recycled clay brick waste demonstrated potential as a PCM carrier for eco-efficient cementitious mortars with thermal energy storage functionality. Full article

The sustainable performance of combustion engines in integrated energy systems (IESs) at a safe thermal level and with high fuel effectiveness is possible if intake air is cooled and the released heat is fully utilized by a heat recovery chiller (HRCh). Herein, the temperature of return hot water, used as a coolant, at the engine inlet is not to be higher than 70 °C to ensure safe, thermally stabilized engine performance. This cannot be ensured by only an absorption lithium-bromide chiller (LBCh) as the most efficient HRCh, which has a COP of about 0.7 and provides a return hot-water temperature of about 75 °C against the required 70 °C, which reduces the engine lifetime by about 10%. To ensure the thermally stabilized performance of the engine in conventional IESs, the residual heat left from the LBCh is ejected into the atmosphere by an emergency radiator with a heat loss of about 25% as the “cost” for safe engine performance. The concept of IES thermal stabilization in terms of both aspects—intake air cooling and the full utilization of the released heat by a combined LBCh boosted by an ejector chiller (ECh), easily implemented into an existing IES—was developed. The appropriate new unified criterion indicators for estimating the rate of thermal stabilization (RS) were adopted to ensure sustainable performance and increased the lifetime of the engine by about 10%, providing an innovative heat recovery intake air cooling system and boosting the conventional IES as a prosperous trend. Thus, for the first time in the practices of IES design and operation, the aggregated effect on engine thermal stabilization, followed by maximizing its efficiency, has been gained due to intake air cooling and full utilization of the heat released as mutually affecting aspects. Full article

Traditional evaluation of Networks-on-Chip is based on aggregate metrics. Most of these metrics (latency, throughput, hop count, packet loss, energy consumption, buffer occupancy, thermal or reliability summaries) compress detailed execution traces into a few scalar values. This dimensionality reduction hides spatial, temporal, and resource-level differences between simulations. This paper introduces an Entropic Structural Observability framework for routing-independent post-simulation analysis of NoC traces. The main idea of the framework is to convert typed packet-level events into probability distributions over used resources, including routers, directed links, time windows, and critical resources. As a final report, the method builds a structural signature. This signature includes normalized entropy, effective support, concentration, spatiotemporal mutual information, distribution drift, topology-aware spatial statistics, buffer-pressure measures, and classical imbalance indicators. The analysis does not modify simulation traces; it operates as a diagnostic layer. It reveals activity distribution, temporal dependence, spatial evolution, resource pressure, and structural imbalance. The framework is evaluated on 256-router 2D and 3D mesh topologies using deterministic and adaptive routing policies under diverse traffic patterns and injection rates, enabling its structural signatures to be examined across different network dimensionalities. The results reveal distinct structural regimes: deterministic dimension-order routing shows broad spatial and temporal dispersion, DyAD exhibits stronger time-space coupling and drift, and Fully-Adaptive presents an intermediate profile with high dispersion but moderate temporal variation. Full article

Background: Climate change is being recognized as a factor associated with increased suicidal behavior, especially in the older adult population. Extreme temperatures, thermal anomalies, and intense weather events can amplify pre-existing physical, psychological, and social vulnerabilities, increasing the risk of suicidal ideation and behavior in older adults. Objectives: This systematic review aims to map the literature on the relationship between climate change and suicidal behavior in older people, identifying risk and protective factors, as well as the prevention and intervention strategies aimed at this age group. Methods: A systematic review was conducted according to PRISMA guidelines. The literature search was performed in the EBSCO PsycINFO, Scopus and MEDLINE (PubMed) databases in the period 2007–2025, using combinations of the keywords “climate change”, “global warming”, “older adults”, “elderly”, “suicide”, “suicidal ideation” and related terms. Out of 35 studies, 16 articles were included in the final analysis. Results: Five thematic areas emerged from the analysis of the studies: (1) risk factors, (2) protective factors, (3) sociodemographic factors, (4) prevention and intervention strategies and (5) variables associated with suicidal behavior. Across the included studies, suicidal ideation, non-fatal attempts, and suicide mortality were examined with differing frequency and are reported separately in the thematic synthesis rather than pooled, reflecting the heterogeneity of outcome definitions and study designs. Significant limitations in the literature remain, including the paucity of longitudinal studies, the widespread use of aggregate data and the limited integration of environmental, social, and psychological factors. Conclusions: Climate change and extreme weather events may contribute to suicidal behavior in older adults. It is therefore necessary to develop multidimensional approaches that address structural vulnerabilities and promote the active role of older adults in climate resilience and social cohesion. Full article

Wearable sensors enable continuous, non-invasive monitoring of physiological and near-body environmental parameters, offering an occupant-centric alternative for thermal comfort assessment and building control. This systematic review analyses 117 studies (2008–2026) using body-worn sensors, tracing them along a four-stage pipeline: sensing, signal integration, comfort modeling, and building actuation. This reveals a previously unquantified bottleneck: while all 117 studies perform sensing and 83 (71%) integrate physiological and environmental signals, only 52 (44%) build predictive models and just five (4%) reach the building-actuation stage, of which only three implement closed-loop, wearable-informed control. Skin temperature (77 studies, 66%) and heart rate (69, 59%) are the most monitored signals, predominantly at the wrist (70, 60%); multimodal configurations are associated with higher accuracy than single-domain approaches. Machine learning models reach median classification accuracies near 90%, though validation strategy matters: leave-one-subject-out reaches 85% versus 90% for within-subject k-fold. Five structural limitations are identified: small, homogeneous samples (median 16 participants), laboratory-dominated designs (73 studies, 62%), inconsistent validation, limited open data, and unresolved multi-occupant aggregation. The field has learned to measure the occupant but not yet to act on the measurement. Closing this gap requires open benchmark datasets, standardized validation including leave-one-subject-out testing and PMV benchmarking, transfer learning, multi-occupant integration, and inclusive recruitment of vulnerable populations. Full article

The development of more sustainable asphalt materials requires modified bitumen binders that combine thermal resistance, adhesion, and deformation capacity. In this study, soft paving-grade bitumen was modified with styrene–butadiene–styrene polymer, oil refinery sludge, titanium slag, and lead-furnace cyclone dust. Binders with bitumen-to-modifying-system ratios from 90:10 to 60:40 were characterized by FTIR, TGA/DSC, XRD, and portable XRF analyses and evaluated using penetration-type consistency, softening-point, qualitative adhesion, and tensile deformation tests. The modifying-system content produced non-monotonic changes in binder properties. Among the investigated formulations, the 75:25 composition provided the most balanced response, with a penetration depth of 8.6 mm, a softening point of 65.0 °C, a maximum elongation of 355.66 mm, and high qualitative film retention on mineral aggregate. In contrast, the 60:40 binder showed increased penetration and the lowest elongation, indicating that excessive modifier loading was unfavorable. The 75:25 binder was subsequently used in small-scale asphalt concrete sections and showed acceptable preliminary behavior during mixture preparation, placement, and compaction. The results demonstrate composition-dependent relationships in the investigated multicomponent system and support further evaluation of selected industrial by-products in modified bitumen binders. Full article

Waterborne polyurethane (WPU) has emerged as one of the most promising environmentally friendly coating materials owing to its low volatile organic compound (VOC) emissions, excellent film-forming ability, good adhesion, and versatility in formulation. However, WPU suffers from several intrinsic limitations including inadequate thermal stability, modest mechanical strength, poor flame retardancy, and a lack of inherent antibacterial activity. To address these deficiencies, phosphorylated microfibrillated cellulose (PMFC), prepared from beech wood sawdust via sequential steam explosion, phosphorylation, and superfine grinding, was employed as a substrate for in situ silver nanoparticle (AgNPs) synthesis and subsequent incorporation into WPU via aqueous blending and solvent casting. PMFC functions through a combined mechanism: the hydroxyl and phosphate groups coordinate Ag⁺ ions, providing nucleation sites, while the nanofibrillar network provides steric stabilization against post-synthesis aggregation. The influence of AgNPs loading (1–10 wt% relative to PMFC at a fixed 1 wt% PMFC content) on the morphology, antibacterial activity, silver release behavior, thermal stability, flame retardancy, and mechanical properties of the resulting composite films was comprehensively investigated using free-standing composite films as a model system. At the optimal Ag loading of 5 wt%, the composite exhibited strong antibacterial activity against Escherichia coli with silver release below 1.15 ppb after 96 h, while tensile strength and Young’s modulus increased by 80% and 298%, respectively, relative to neat WPU. At high Ag loadings (70–80 wt%), the composites achieved conductive-level surface resistivity (~3 log Ω) through percolation network formation, demonstrating antistatic functionality. This study provides an effective strategy for fabricating WPU composite films with combined antibacterial, mechanical reinforcement, and antistatic capabilities. Full article