Search Results (175)

Background and Objectives: Warm injectable gutta-percha techniques may improve three-dimensional filling of complex canal anatomy, but heat transfer to the external root surface may threaten periodontal tissues when the 47 °C threshold is exceeded. This in vitro study quantified external root-surface temperature changes during obturation with the Woodpecker FI-G/FI-P system and compared manufacturer preset temperatures with actual device output. Materials and Methods: Twenty extracted single-rooted human teeth standardized to 18 mm were prepared and assigned to obturation at 180 °C (Group A, n = 10) or 230 °C (Group B, n = 10). Infrared thermography recorded coronal, middle, and apical root-surface temperatures. A second device-based experiment measured FI-G and FI-P output at preset temperatures of 150 °C, 180 °C, 200 °C, and 230 °C. Results: The 230 °C setting produced significantly higher middle-third temperatures than the 180 °C setting (41.84 ± 5.52 °C vs. 36.99 ± 3.21 °C; p = 0.027; Cohen’s d = 1.07), whereas coronal and apical differences were not significant. The highest external root-surface value was 49.6 °C, and 3/10 specimens obturated at 230 °C exceeded 47 °C in the middle third. A significant coronal-to-middle gradient reversal was observed at 230 °C (p = 0.045). Device measurements showed strong attenuation between preset and output temperatures: at 230 °C, the FI-G tip base reached 150.0 °C but the tip apex reached 51.3 °C, while FI-P plugger tips reached 120.0 °C. Conclusions: The 180 °C setting produced a more predictable thermal profile, whereas 230 °C increased localized middle-third overheating risk. These in vitro findings support cautious temperature selection, especially in teeth with reduced dentin thickness or compromised root anatomy. Full article

Effective thermal management is crucial for the performance, thermal safety, and lifespan of lithium-ion batteries in electric vehicles (EVs). Thermal management strategies are essential for preventing overheating, thermal imbalance, and the associated risk of thermal runaway. Nanofluids are emerging and attracting considerable attention as potential coolants for high-power energy storage and electronics systems. This review updates and summarizes the most recent advances in nanofluid-based cooling strategies for battery thermal management systems (BTMSs) over the past five years, emphasizing their implications for battery thermal safety. Three main nanofluid-based cooling strategies have been evaluated in depth, including nanofluid-based indirect liquid cooling, nanoparticle-enhanced PCM cooling, and nanofluid-based heat pipe cooling. Various nanofluid formulations, including mono, hybrid, and ternary nanofluids, have been considered and evaluated for their heat dissipation under high charge/discharge and abuse-relevant conditions. Thermal and hydraulic performance characteristics, including maximum temperature, maximum temperature difference, and pressure drop, have been comprehensively evaluated for different nanofluid-based cooling strategies. The findings demonstrated that nanofluids significantly improved heat transfer rates and enhanced temperature control efficiency. In particular, hybrid and ternary nanofluids exhibit superior thermal performance and effectively suppress the escalation of safety-critical temperatures. Beyond summarizing cooling performance, this review further discusses the role of nanofluid-based cooling strategies as functional thermal-control layers within intelligent BTMS architectures. Particular attention is given to their compatibility with sensing networks, BMS-/VCU-level supervisory control, predictive thermal models, actuator responsiveness, fault-warning algorithms, and long-term reliability under realistic driving and fast charging conditions. Therefore, this review provides architecture-oriented insights for developing safe, energy-efficient, and control-ready BTMSs for next-generation high-power and connected EVs. Full article

In distributed renewable energy systems, load fluctuations caused by energy resources and energy storage increase the overload risk of distribution transformers, which may accelerate insulation aging and cause overheating, and undermine operational reliability. For transformer condition monitoring, this risk is reflected not by a single variable but by heterogeneous sensing observations acquired from electrical, thermal, and equipment status monitoring channels. Because full-scale inspection of latent defects is impractical under limited staffing and equipment resources, accurate overload risk prediction is important for sensor-driven maintenance allocation. With such motivations, this paper proposes a Transformer Overload Risk Assessment (TORA) approach for robust overload risk prediction under nonstationary load conditions. First, a feature matrix is constructed by jointly incorporating static features that capture long-term drift and dynamic features extracted from multisource sensing and supervisory signals that reflect short-term fluctuations. Then, static and dynamic features are assessed with Edge-based Static Feature Risk Assessment (E-SFRA) model and Cloud-based Dynamic Feature Risk Assessment (C-DFRA) model, respectively, according to their temporal and statistical characteristics. Next, a periodic calibration model (CE-PAA) is established through a cloud–edge loop, which uses low-latency edge updates and high-capacity cloud computation as feedback. Finally, risk score fusion (RSF) fuses generated static and dynamic risk scores to integrate cloud and edge strengths. The case study results indicate that TORA can transform heterogeneous monitoring signals into calibrated risk information in the studied single power plant scenario, providing useful support for multisource sensor data fusion, transformer condition monitoring, and maintenance decision making. Further validation using multi source field datasets is still needed to assess its cross scenario generalization ability. Full article

Photovoltaic (PV) installations require maintenance prioritization models capable of ranking technically diverse failure modes under operational, safety, and serviceability constraints. Conventional Failure Mode and Effects Analysis (FMEA) approaches often cannot integrate downtime, cost, safety, and detectability into a single transparent workflow. This study develops a hybrid Particle Swarm Optimization (PSO)-FMEA-VIseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) framework for maintenance prioritization of eight representative PV failure modes. Classical FMEA was used as a diagnostic baseline, a seven-criterion maintenance matrix was constructed, PSO calibrated criteria weights, and a criticality-oriented VIKOR compromise-ranking procedure generated the final ordering. Semi-empirical operational and service log evidence was used only to anchor the interpretation of occurrence, direct cost, and downtime; it was not treated as a real-time fault-detection dataset. The results identified inverter overvoltage shutdown/grid incompatibility, cable insulation degradation, and junction box overheating as the highest maintenance priorities. Their ordering differed from classical Risk Priority Number (RPN) results, showing that frequency alone does not adequately represent maintenance urgency. Sensitivity analysis confirmed the stability of the two leading alternatives under different VIKOR strategy parameters. The framework provides a discriminative decision support tool for inspection planning, service scheduling, and corrective-action targeting in grid-connected PV systems, while further validation on larger Supervisory Control and Data Acquisition (SCADA)- or inverter-log-based datasets remains necessary. Full article

In response to the frequent safety incidents associated with the core electrical systems (i.e., traction battery, charging system, and drive motor) of new energy vehicles (NEVs) and the lack of forward-looking quantitative risk assessment methods in existing detection and diagnostic technologies, this study introduces the Layer of Protection Analysis (LOPA) methodology into the field of NEV safety. Unlike qualitative methods (e.g., FMEA, FTA) or purely data-driven diagnosis, this work establishes a tailored semi-quantitative LOPA framework that defines scenario-specific independent protection layer (IPL) identification criteria and probability of failure on demand (PFD) assignment rules for NEV applications. Typical risk scenarios, including battery thermal runaway, electrical faults in charging systems, overheating of drive motors, and battery internal short circuits caused by mechanical abuse, are systematically analyzed in terms of their failure mechanisms and evolution processes. A tailored quantitative risk assessment framework is established and applied to conduct full-process risk evaluations for the four scenarios. The results indicate that, under the synergistic effect of multiple protection layers—including inherently safe design, basic process control systems, safety instrumented systems, and physical protection measures—the accident consequence frequencies of all scenarios are significantly lower than the tolerable risk thresholds. This verifies the applicability and effectiveness of the LOPA method in NEV safety analysis. The proposed quantitative framework provides a scientific basis for safety design optimization, identification of critical protective elements, and operation and maintenance strategy formulation throughout the lifecycle of NEVs. Furthermore, the limitations of data portability from process industries are discussed, and sensitivity analyses are conducted to confirm the robustness of the conclusions. Full article

Climate change is expected to increase the overheating risk and cooling demand in buildings. This study investigates the thermal comfort and energy performance of a retrofitted glazed healthcare space using an integrated approach combining long-term field measurements with validated dynamic energy simulation. The analysed space, originally an external terrace later enclosed for medical use, is characterised by a high glazing ratio and substantial solar exposure. Continuous in situ measurements of indoor air temperature, relative humidity, and CO₂ concentration were conducted during winter and summer periods. Thermal comfort and indoor air quality were assessed according to international standards. A calibrated EnergyPlus model was used to evaluate performance under present (TMY) and future (2050, 2080) climate scenarios. The results show frequent overheating under current conditions, with peak operative temperatures exceeding 30 °C and comfort maintained for as little as 41% of the summertime in highly exposed zones. By 2080, overheating will intensify (up to 33 °C in simulations), while the cooling demand will nearly double (from 14 to 29 kWh/m²). Hybrid ventilation cooling strategies reduce cooling demand by up to 39% and maintain acceptable comfort for up to 78% of annual hours. The findings highlight the critical role of solar protection, hybrid control, and vegetation in improving the climate resilience of glazed healthcare spaces. Full article

Against the global backdrop of carbon neutrality and the green transition of the construction sector, modern timber-framed buildings have emerged as a core enabler of sustainable construction. However, a systematic synthesis of research on indoor hygrothermal environments and thermal comfort in such buildings remains lacking, and the underlying coupling mechanisms—as well as pathways for performance optimization—are still insufficiently understood. To address these gaps, this study aims to systematically characterize and evaluate the performance features of indoor thermal and moisture environments in modern timber buildings, and to identify the key influencing factors and their underlying mechanisms. In accordance with the PRISMA 2020 guidelines for systematic reviews, this study identified and analyzed 203 high-quality peer-reviewed publications retrieved from three major academic databases, covering the period 2010–2025. Specifically, the literature search was conducted across the Web of Science, Scopus, and the China National Knowledge Infrastructure (CNKI), and visualization analysis was performed using VOSviewer 1.6.20 software. The results indicate that timber-framed buildings exhibit distinctive indoor hygrothermal characteristics: rapid temperature response, strong humidity buffering capacity, and superior thermal insulation performance compared with concrete structures, enabling indoor relative humidity to remain stably within the thermally comfortable range. Nevertheless, challenges persist, including summer overheating and elevated risks of mold growth under hot-humid conditions. Furthermore, the PMV model demonstrates significant predictive deviation for thermal comfort in timber-framed buildings; its application thus requires calibration incorporating both the hygrothermal properties of timber materials and occupants’ psychological adaptation. This study synthesizes the current state of research, identifies key influencing factors, and proposes climate-responsive optimization strategies to advance the development of robust thermal comfort models and support the low-energy, high-comfort design of timber-framed buildings. Full article

Great Britain has a temperate climate, but like other countries, its weather patterns have already been profoundly affected by climate change, and the changes are very likely to continue for decades. It also has an older building stock than most other countries, which may mean it is more difficult to adapt the built environment to reduce vulnerability to climate hazards. However, Great Britain has excellent mapping and buildings data. The built environment is better described than most other countries, and the authors’ work on the National Buildings Database for Great Britain, which draws together the most reliable sources of data covering non-domestic buildings in England, Scotland and Wales, provides an unparalleled opportunity to evaluate how many people will be affected by climate hazards. There has been considerable research effort assessing how housing will be affected by climate change, but so far much less systematic assessment of impacts on non-domestic buildings. Here, the authors examine three aspects of climate hazard affecting people in non-domestic buildings in Great Britain: (1) Overheating—How many and what types of non-domestic buildings are vulnerable to overheating risks in a heat wave? What total floor area is affected, and how many people typically occupy these buildings? (2) Flooding—How many and what types of non-domestic buildings are threatened by flooding now and in 2080? How much floorspace is threatened, and how many people typically occupy these buildings? (3) Safe space—How much air-conditioned ‘safe space’ is available where people vulnerable to overheating risks could retreat to in an emergency overheating event (e.g., schools or hospitals)? How many people could be accommodated, and what fraction of the total GB working population does this represent? We propose five new metrics to assess two of the immediate hazards posed by climate change (overheating and flooding) and to begin to assess to what extent Great Britain could find temporary accommodation for people displaced by these hazards. Full article

The widespread adoption of photovoltaic systems in residential electrical installations has increased the importance of Automatic Transfer Switches (ATSs) for ensuring power continuity during grid outages. However, many low-cost ATS solutions available on the market prioritize economic efficiency over operational safety, leading to significant risks under fault conditions. This paper investigates a real overvoltage incident in a residential three-phase installation equipped with a photovoltaic inverter and an ATS, which resulted in the failure of multiple electronic loads. The study reconstructs the event and demonstrates that the loss of the neutral conductor during backup operation caused severe phase voltage imbalance, generating overvoltage conditions across lightly loaded phases. A simplified electrical model is used to explain current paths and voltage redistribution under asymmetric loads, highlighting the critical role of correct neutral switching in ATS design. Two commercially available ATS architectures, one based on a changeover-contact mechanism and one employing four-pole miniature circuit breakers, are experimentally evaluated. The evaluation reveals major design deficiencies, including the absence of protective elements for control circuits, reliance on mechanical end-position limiters, and the use of switching devices not intended for frequent source transfer. These shortcomings introduce risks such as uncontrolled actuator operation, overheating, mechanical damage, and potential fire hazards. To overcome these limitations, a new ATS architecture was developed using a phase-monitoring relay, interlocked ABB contactors, and dedicated fuse protection for all control circuits. Detailed laboratory measurements were conducted to characterize contactor switching times and internal relay command delays. By optimizing the command sequence, the proposed ATS achieves predictable, fault-tolerant operation with competitive transfer times, representing a meaningful safety improvement over the evaluated commercial alternatives. The proposed solution is scoped to three-phase residential installations equipped with a hybrid photovoltaic inverter providing a dedicated backup output, operating within TN-S or TN-C-S earthing systems with a maximum grid connection capacity of 21 kW. Full article

This study presents an application-oriented CFD–FEM integrated workflow for analyzing chamber-side field non-uniformity and kelp-side thermal response during infrared drying. A three-dimensional steady-state CFD model was first established to reconstruct the chamber temperature, airflow, and incident radiation fields under certain operating conditions. Numerical consistency was checked through residual convergence; monitored variables; and global mass balance, for which the net mass imbalance was 0.004077 kg s⁻¹. The reconstructed mid-plane fields were then processed in MATLAB to extract the mean values, extrema, and coefficients of variation, and a composite objective function was used to screen the tested operating conditions in terms of field uniformity, temperature band compliance, and overheating risk. The thermal loads obtained via CFD were subsequently mapped onto a kelp finite element model to simulate the transient surface temperature evolution. Among the tested cases, case01 yielded the lowest composite objective value (J = 0.4535); its mapped kelp response showed a mean surface temperature of 62.23 °C and a maximum temperature of 63.57 °C at the exported time step. The proposed framework is therefore suitable for thermal response assessment and operating condition screening, although determining the full drying behavior still requires coupling of moisture transfer and improved experimental validation. Full article

The continuous current dissipation of direct current grounding electrodes generates intense Joule heat, causing severe soil moisture loss and localized thermal runaway. Traditional static models ignore the temperature-dependent nature of soil parameters, leading to dangerous underestimations of actual temperature rises and thermal risks. To address this critical issue, this study establishes a bidirectional dynamic electro-thermal coupled model for a vertical grounding electrode using COMSOL Multiphysics. Comparative analysis demonstrates that the dynamic model accurately reproduces the late-stage accelerated temperature rise observed in experiments, proving its necessity over static methods. Simulations reveal that increased soil resistivity governs heat generation and directly causes a dramatic surge in both grounding resistance and maximum step voltage. In two-layer heterogeneous soils, current is forced into lower-resistivity regions, triggering extreme localized overheating. To mitigate this, expanding the cross-sectional radius of the coke bed effectively suppresses the thermal concentration. These findings provide quantitative evidence and non-uniform design guidelines for the safe operation and thermal protection of grounding electrodes under complex geological conditions. Full article

High-altitude and high-speed aircraft generate substantial aerodynamic heat during flight, creating a harsh thermal environment in the engine compartment that risks overheating and burnout of control components and fuel and lubricating oil accessories. Consequently, the thermal protection system (TPS) design for engine accessories has become one of the key technologies in hypersonic vehicle design. Based on certain TBCC, this paper uses a modular active-passive integrated TPS design and employs the quality management experimental design tool to optimize the design and decouple the method proposed on the modular design boundaries. This paper is the first to combine modular design with design of experiments (DOE) tools and apply them to the TPS of high-altitude and high-speed combined power accessories. The design scheme is optimized by identifying the main influencing factors. The optimized TPS scheme decreases the performance loss by 10% and increases cooling efficiency by 22–26%. The proposed engineering method shortens the development cycle significantly and improves efficiency by 78%. The modular design method for accessory TPS provided in this paper has good engineering applicability and can be widely used in the early stages of thermal protection scheme design, scheme optimization, scheme selection, and overall thermal management of hypersonic combined power systems. Full article

Covered courtyards are increasingly being adopted as a passive strategy for the climatic rehabilitation and adaptive reuse of historic buildings. However, their thermal behaviour is strongly conditioned by roof geometry, local climate conditions, and future climate warming, aspects that have not yet been comparatively addressed within a climate resilience framework. This study evaluates the energy and thermal performance of three representative roof typologies for covered historic courtyards—glazed dome, glazed flat roof, and south-facing sawtooth roof—across two Mediterranean climates of contrasting severity (cold continental and warm–dry), considering both current and future climatic conditions (2050–2080). Additionally, two design approaches are compared: a baseline design (BD), based exclusively on geometric configuration and standard glazing, and an enhanced passive design (EPD), which incorporates improved glazing, controlled natural ventilation, and seasonal solar control. Dynamic simulations using EnergyPlus/DesignBuilder are employed to analyse heating and cooling demands, free-running thermal behaviour, overheating risk, and the climatic robustness of each solution. The results show that roof geometry constitutes the dominant factor governing the long-term thermal resilience of covered courtyards, particularly under future climate warming scenarios, while enhanced passive strategies significantly mitigate cooling demand and overheating in the most penalised typologies. The south-facing sawtooth roof consistently exhibits the highest climatic robustness under free-running conditions across the analysed scenarios, whereas the glazed dome and flat roof solutions display greater climatic sensitivity and benefit more substantially from the application of enhanced passive design strategies. Overall, the results provide quantitative design criteria to support resilient interventions in historic covered courtyards in Mediterranean climates under climate change. Full article

This paper investigates summertime indoor overheating in naturally ventilated public buildings located in a cool temperate Baltic climate, where buildings are traditionally designed for heating-dominated conditions. The study is based on long-term field measurements conducted in two naturally ventilated rooms (a school classroom and a physician’s consultation office) and aims to quantify indoor overheating and examine indoor–outdoor thermal relationships. Indoor air temperature was continuously monitored and analysed together with concurrent outdoor air temperature and global solar radiation data. Overheating was assessed using fixed temperature thresholds (26 °C and 28 °C), exceedance hours, degree-hours, diurnal distributions, and indoor–outdoor temperature correlations; adaptive comfort criteria were not applied. The results reveal a pronounced contrast between the two spaces. The classroom experienced frequent and severe overheating and strong coupling to outdoor air temperature (R² = 0.60), whereas the physician’s office exhibited limited exceedance and a more buffered thermal response, with weaker indoor–outdoor coupling (R² = 0.32). These findings indicate substantial room-to-room variability in overheating behaviour, even under the same climatic conditions. While derived from a limited two-room case study, the results suggest that room-level assessment may be valuable for identifying overheating risks in naturally ventilated public buildings in cool-climate regions. Full article

Climate change is altering the use of public open spaces in historical urban environments, compounded by urban heat island effects. Especially considering urban squares, rising temperatures increase health risks for outdoor users, particularly for vulnerable individuals (by, e.g., age and fragility). Rapid risk assessment under current and future climate scenarios can exploit integrated simulations to support the process, considering both real-world environments and Built Environment Typologies (BETs), which represent the recurring morphological, constructive, and material features of such urban squares. Simulation-based approaches can also support the assessment of mitigation strategies considering sustainability, reversibility, visual integration, and compatibility with the heritage. This work proposes a framework for simulation-based heat risk assessment of outdoor users under current and future (2050 and 2080) overheating scenarios and considers pre- and post-mitigation conditions of urban squares. Outdoor temperature conditions are simulated using ENVI-met, enabling the multiscale assessment of users’ heat stress and thresholds in exposure timings before critical dehydration. The approach is applied to two Italian historical urban squares in Bari and Naples, and to their associated BETs. The results highlight the framework’s capabilities in addressing the impact of climate scenarios and pre-/post-mitigation conditions, considering the local and global conditions of the urban squares. Moreover, the observed similarities between POSs and their corresponding BETs demonstrate that these archetypes can support preliminary risk assessments, providing decision makers with a rapid overview before adapting analyses and mitigation strategies to the specific characteristics of each urban square. Full article