Search Results (7,031)

The phase-change material (PCM) layer plays a critical role in governing the heat transfer characteristics of building walls. To evaluate this effect, two experimental test rooms with identical structural configurations were constructed and monitored under summer solar radiation conditions. One room incorporated an external phase-change mortar layer, whereas the other utilised a conventional, ordinary mortar layer wall to serve as a reference control. The heat transfer characteristics of the walls of both rooms were comprehensively evaluated under natural weather conditions. The experimental results indicate that, under the tested summer conditions, an external phase-change mortar layer with an appropriate phase-change temperature can improve the thermal regulation performance of the wall system. In particular, the wall incorporating PCM with a phase-change temperature of 32 °C effectively reduced the external surface temperature, with the maximum external surface temperature remaining below 44 °C. However, when the external surface temperature exceeds 44 °C, the PCM layer does not contribute to temperature reduction; instead, it may increase both the surface and overall wall temperatures due to ineffective phase change under mismatched thermal conditions. This study provides support for the engineering applications and parameter optimisation of phase-change thermal storage walls. Full article

Rural low-carbon planning requires evaluation tools that connect carbon-related performance with the ecological, socioeconomic, and infrastructure conditions of rural settlements, yet carbon inventories and conventional human-settlement assessments do not fully integrate these dimensions. This study developed an exploratory carbon-benefit-oriented sustainability diagnostic and applied it to Qingge Village, Fujian Province. Fuzzy Delphi screening retained 27 indicators across ecological, social, production, and engineering subsystems; Delphi consultation generated expert-based weights; a dimensionless ratio transformation standardized the indicator values; threshold, standardization, and weighting sensitivity analyses evaluated the stability of results across analytical specifications. The primary composite score was 0.413 compared with 0.590 under the target-achievement transformation, and both expert-weighted transformations ranked subsystem contributions as production, ecological, social, and engineering. The ecological and production subsystems performed more strongly against the selected references than the social and engineering subsystems, whereas fully equal global weights placed ecology ahead of production. The principal diagnostic priorities were household energy emissions, green agricultural upgrading, public-transport access, and recorded energy-efficient building coverage. These findings indicate that the diagnostic can organize village-scale low-carbon planning priorities and translate multidimensional performance evidence into a sequenced set of spatial improvement options. This study therefore provides a transparent and practically applicable approach for linking carbon-related indicators with rural human-settlement planning and supporting evidence-informed low-carbon revitalization. Full article

Conventional early-warning methods for geohazards along railways rely largely on single observations, empirical criteria or static analysis, and struggle to meet the demands of corridor-scale screening and dynamic tracking. To address this gap, a railway-oriented Perception–Assimilation–Decision (PAD) closed-loop early-warning framework is proposed. The evolutionary patterns of typical geohazards along railways, including landslides, rockfalls, debris flows and settlement, are reviewed together with the application scope and limitations of multi-source monitoring techniques. Additionally, differentiated assimilation strategies are clarified, with continuous deformation and hydro-mechanical state updating for plastic failure and damage-sensitive evidence and critical-state identification for brittle failure. On this basis, a mechanism–data dual-driven assimilation paradigm and a two-scale PAD organisation, comprising corridor-scale spatial screening and site-scale state updating, are introduced. Recent applications show that data assimilation has shifted from correcting a single monitoring variable toward the dynamic coupling of multi-source observations with physical models. By establishing the logical chain from multi-source perception to state updating and finally to railway engineering response, the PAD framework transforms the traditional anomaly-identification-based warning mode into closed-loop risk management. The results provide a reference for building geohazard early-warning systems and engineering-oriented response along railways. Full article

Wastewater treatment systems are under increasing pressure to improve nitrogen removal while reducing carbon emissions, yet the deployment of anaerobic ammonium oxidation (anammox) remains constrained by uncertainty about technical readiness, operational robustness, nitrous oxide (N₂O) emissions, life-cycle carbon performance, monitoring capacity, and transferability across wastewater contexts. This study uses dynamic topic modelling and trend assessment of 998 publications from 2001 to 2025 to synthesize deployment-relevant evidence for anammox-based wastewater treatment. The results indicate that the field has shifted from reactor start-up and process-parameter optimization toward microbial regulation, mainstream process integration, coupled nitrogen-removal strategies, and intelligent control. Building on these topic-evolution patterns and reported engineering evidence, this study provides an evidence-based qualitative appraisal of deployment-readiness signals and evidence gaps, distinguishing comparatively mature side-stream applications from mainstream systems that still require monitored demonstrations, transparent N₂O accounting, life-cycle assessment, and locally validated operating data. The study argues that anammox should be evaluated as a technology with potential but conditional carbon-saving benefits: its potential carbon-saving benefits depend on operational evidence specific to each application stage, carbon-accounting credibility, and implementation capacity, rather than assuming that research activity alone justifies broad deployment. Full article

The construction phase of sports buildings is characterized by high carbon emission intensity, yet existing studies have largely focused on operational energy consumption and static life-cycle accounting, with no systematic investigation of the dynamic interactions among labor, materials, machinery, and environmental factors during construction. To fill this gap, this study develops an agent-based modeling (ABM) framework for a university natatorium in Shaanxi, China, to assess carbon emissions during the civil engineering construction phase and analyzes the independent and synergistic effects of labor, materials, machinery, and environmental factors. The simulation results show that, among single factors, material recycling achieves the highest reduction efficiency (57.93%, under the avoided-burden approach, representing a technical upper-bound estimate), followed by labor skill improvement (3.08%) and machinery maintenance (0.26%), while adverse weather increases carbon emissions by 13.20%. Multi-factor synergy analysis reveals that labor skill improvement buffers weather-induced increases (synergy: +610.49 t, 4.26%), and the full-intervention scenario achieves a 52.33% net reduction under adverse weather, though weather impacts cannot be fully offset. The proposed framework provides methodological support and a decision-making basis for low-carbon construction planning of natatoriums and similar buildings. Full article

The reuse of construction and demolition waste in cementitious materials supports the development of sustainable low-carbon composites and circular economy strategies. This study investigated the influence of recycled ceramic fine aggregate (RCerFA) and recycled concrete fine aggregate (RConFA) on the mechanical properties, freeze–thaw durability, pozzolanic potential, and environmental performance of cement mortars prepared with different cement types. Mortars containing 20% and 40% replacement of natural sand with recycled aggregates were evaluated through strength testing and freeze–thaw resistance assessment, while SEM analysis and pozzolanic potential were assessed on separate mortars in which 25% of the cement binder was replaced with the recycled materials, alongside carbon footprint calculations based on global warming potential (GWP), using the recycled materials directly after the crushing process without additional grinding. The results showed that mortars containing recycled concrete fine aggregate generally maintained satisfactory mechanical performance and freeze–thaw resistance, particularly at the 20% replacement level. In contrast, 40% RCerFA reduced mechanical performance and freeze–thaw resistance. Neither recycled material demonstrated confirmed pozzolanic reactivity in its unground state. Although one RConFA mixture exceeded the 75% compressive strength index criterion, this result alone was insufficient to confirm a chemical pozzolanic reaction. Environmental assessment demonstrated that cement type had a greater influence on carbon footprint than recycled aggregate incorporation. The study confirms the potential applicability of recycled fine aggregates in sustainable low-carbon cement mortars and explores their possible use as low-energy supplementary cementitious components. Full article

Double-skin façades (DSFs) offer a promising building-envelope strategy for improving thermal management by promoting heat’s removal from the façade cavity before it is transferred toward the indoor environment. This study numerically investigates the influence of cavity width on the thermo-fluid performance of a mechanically ventilated DSF under summer operating conditions. A two-dimensional computational fluid dynamics (CFD) model was developed using the RNG k-ε turbulence model together with the discrete ordinates radiation model. Mechanical ventilation was imposed through a velocity inlet of 0.765 m s⁻¹, with an inlet air temperature of 17 °C and a solar radiation intensity of 365.4 W·m⁻². The numerical model was validated against published experimental temperature measurements, yielding an average absolute relative error of approximately 5.65%. The validated model was subsequently applied to cavity widths ranging from 0.10 to 0.70 m. Increasing the cavity width substantially modified the airflow development and thermal field. The monitored temperature decreased from 31.66 °C at 0.10 m to 17.64 °C at 0.50 m, while further enlargement produced only minor reductions to 17.43 and 17.28 °C at 0.60 and 0.70 m, respectively. The total heat-transfer rate increased from approximately 1000 W at 0.10 m to a maximum of 1388 W at 0.50 m before slightly decreasing to 1379 and 1376 W at 0.60 and 0.70 m, respectively. This temperature reduction enhances heat removal from the façade cavity, helping to limit heat transfer toward the indoor environment and improve indoor thermal comfort under summer conditions. These results demonstrate a non-monotonic relationship between cavity width and heat-removal performance, with 0.50 m providing the highest heat-transfer rate among the investigated configurations. This result is specific to the geometry, boundary conditions, ventilation rate, and operating conditions considered in the present study. It should not be interpreted as a universally optimal cavity width for mechanically ventilated DSFs. The findings highlight the importance of cavity-width selection in the thermal management and design of mechanically ventilated DSFs for energy-efficient building envelopes. Full article

In the hyper-arid climate of Riyadh, Saudi Arabia, the building envelope is a critical determinant of energy demand and occupant comfort. This paper reports an experiential-learning experiment in which undergraduate architectural-engineering students applied building performance simulation (BPS) as a generative design instrument rather than a post-design audit tool to their own real capstone building, a 6581 m² mixed-use development. Using Sefaira (EnergyPlus/Radiance engines), they iteratively diagnosed, tested, and refined envelope decisions against the prescriptive thresholds of the Saudi Building Code (SBC 601). A baseline analysis revealed a high Energy Use Intensity (EUI) of 139 kWh/m²·yr, driven primarily by solar heat gains and an “overlit” floor plate that exceeded Annual Sunlight Exposure (ASE) thresholds. Students then implemented passive interventions—improved glazing U-value (0.50 W/m²·K), reduced Solar Heat Gain Coefficient (SHGC 0.20), and external shading fins. These produced a 6.95% EUI reduction (139→130 kWh/m²·yr) and a 17.24% fall in cooling energy. The energy outcomes are consistent with established findings for hot-arid envelopes and are therefore treated here not as the novelty but as the technical evidence the students generated. Daylighting analysis confirmed improved distribution and reduced glare risk, although ASE remained above the LEED v4 threshold. The contribution is pedagogical: the study documents a replicable framework through which a design studio develops students’ technical competence in performance-driven envelope design, evidenced by their progression from uninformed parameter selection to code-referenced design reasoning and by the difficulties and trade-offs they encountered. Full article

Post-earthquake field investigations provide significant contributions to earthquake-resistant building design. Especially after devastating earthquakes, determining the damage levels in buildings is an important issue for structural engineering. The Kahramanmaraş earthquake, which occurred on 6 February 2023, had a devastating impact over a wide area. Numerous reinforced concrete buildings collapsed or were severely damaged. Significant damage was observed not only in older buildings but also in newer ones. Even buildings that were yet to be in service suffered significant damage. This study examines the structural damage of a newly constructed and severely damaged after the 2023 Kahramanmaraş earthquakes 13-story reinforced concrete building in Malatya province. The damage caused by the earthquake was investigated through field observations. Concrete core samples were taken from the damaged building, and reinforcement checks were performed using a rebar scanner. Nonlinear time-history analyses were conducted using the measured data. The results of the numerical analyses were compared with site observations of earthquake-induced damage. The results obtained from the nonlinear analyses appear to be consistent with the field observations. Full article

The requirement of energy efficiency in designs of sustainable aquaponics has brought about the incorporation of passive solar systems and earth–air heat exchangers (EAHE). In this study, an evaluation of the physiological effects that arise from the implementation of the use of underground thermal stabilization by means of heat exchangers and the limitations of this technology will be carried out. The greatest strength of this technology is the “thermal buffer” that is created in the physiology of the fish; this technology makes the fish resilient to changes in environmental temperatures, thus reducing energy usage. However, the weakness is that there are ecological risks involved, such as moisture build-up due to low air exchange and biofilm formation in pipes, which occur when this technology is used without biological controls. This review highlights the critical balance between energy efficiency and biological safety while analyzing the impacts of these technological advantages on growth performance, metabolic regulation, and physiological stress responses in fish. This review demonstrates that, beyond improving heating and cooling efficiency, successful implementation of EAHE-assisted passive solar aquaponics depends on balancing engineering performance with biological requirements, including thermal regulation, gas exchange, humidity control, and biosecurity. Full article

Heating, Ventilation, and Air Conditioning (HVAC) systems account for 60–70% of residential electricity consumption in Oman, where extreme desert climate, with temperatures regularly exceeding 45 °C create substantial cooling demands. Unlike general reviews of smart HVAC controls, this study specifically evaluates the applicability and performance of advanced control strategies for Omani residential buildings operating under extreme heat conditions, synthesizing evidence from international research, the Gulf Cooperation Council (GCC) region, and Oman. Based on a systematic review of peer-reviewed literature published between 2015 and 2025, this analysis examines Model Predictive Control (MPC), Deep Reinforcement Learning (DRL), Fuzzy Logic Control, and Internet of Things-based integrated approaches. International studies demonstrate that MPC strategies achieve energy savings of 16–40% compared to conventional thermostatic control by utilizing dynamic building thermal models to optimize control sequences over finite prediction horizons. DRL-based controllers achieve energy reductions of 17–23% through adaptive learning of optimal policies without requiring explicit system models, offering adaptability to dynamic occupancy patterns. Real-world implementation case studies from Oman and the GCC region—including the GUtech EcoHaus net-zero energy building and national-scale retrofit programs—demonstrate realized energy savings ranging from 25–75%, with higher savings achieved through comprehensive interventions that combine advanced controls with high-performance building envelopes. These findings suggest that substantial potential for reducing residential energy consumption while maintaining occupant thermal comfort under Oman’s extreme climatic conditions is achieved through the integration of advanced HVAC control strategies with high-performance building envelopes. Future research may address the development of occupant-centric adaptive comfort models calibrated for extreme heat conditions and context-specific control strategies that account for regional occupancy patterns and cultural preferences. Full article

Orange waste (OW) is an example of biomass that has a potential for nutrients and energy recovery. However, its use in biological processes, e.g., anaerobic digestion (AD), still poses a significant technological challenge due to the presence of hardly biodegradable lignin and compounds toxic to the microorganisms. To release its energetic potential, the use of an adequate pre-treatment method might be a solution. This research evaluated the efficacy of various pre-treatment strategies, i.e., acoustics (AC) and hydrodynamic cavitation (HC), microwave radiation (MR), and the impact of solidified carbon dioxide (SCD) in improving the properties of OW, including organic compound content, fiber components, morphological structure, and generation of toxic intermediates. The obtained results showed that HC might be considered as the most efficient pre-treatment strategy prior to its further AD decomposition. For this strategy, an over 2-fold increase in biodegradability index, expressed as the DOC/TOC (dissolved to total organic carbon) ratio, was found. In turn, the other analyzed parameters, i.e., removal of organic compounds and delignification degree, were established at the favorable level of 63 and 56%, respectively. This effect was achieved with the lowest energy demand of 0.35 MJ/kgVS. However, HC favored the generation of AD inhibitors. However, to fully assess the impact of selected methods on AD performance, further experiments should be conducted. Full article

In recent years, traditional cast-in-place concrete construction for pre-drilling engineering in unconventional natural gas fields has generated large amounts of waste concrete, consumed significant resources, and prolonged project schedules. To address these issues, this study proposes a prefabricated pavement slab system as a green and low-carbon alternative. Based on vehicle load surveys at shale-gas well sites in southwestern China, three loading conditions (design, overload, and ultimate axle loads) were defined. Theoretical calculations were then performed for reinforcement design, crack-width control, and local bearing capacity verification. A full-scale precast slab (3000 × 1495 × 150 mm) was fabricated and tested under static monotonic loading to measure deflection, crack development, steel strain, and concrete strain until failure. Separately, a three-dimensional finite element model of a four-panel pavement system (including a mortar-leveling layer and soil subgrade) was developed in ANSYS to simulate static and, preliminarily, moving loads. The experimental slab reached an ultimate load of about 365 kN (based on a single specimen, and thus not statistically representative), with ductile bending failure and crack/deflection patterns typical of reinforced concrete. The numerical model reproduced the cracking load and peak capacity with deviations below 17% from the test data, though post-cracking deflections were underestimated. Overall, the results demonstrate that the proposed prefabricated system is structurally feasible for heavy-duty drilling sites. It enables factory production, rapid on-site assembly, and reuse after dismantling, thereby reducing construction waste, shortening timelines, and supporting energy conservation and emission-reduction goals in the context of China’s green building policies. Full article

Engineering curricula offer students few structured opportunities to practice reasoning about problems whose social, political, and economic dimensions are as consequential as their technical ones. This paper reports an exploratory qualitative study of an undergraduate engineering elective in which students investigate a wicked problem of their choice using multiple systems mapping tools, with an explicit emphasis on problem exploration over solution convergence. Drawing on semi-structured post-course interviews with 13 purposively sampled students across three cohorts, including a case-based transfer task set in an unfamiliar sociotechnical context, we examine what capacities students describe developing and how specific mapping tools mediate their reasoning. Interviews were analysed through a combined deductive–inductive coding approach organized by the STOP (Systems Thinking for Opportunity) framework, an analytic scaffold that links Richmond’s systems thinking competencies, the KEEN entrepreneurial mindset dimensions, and Ardichvili et al.’s opportunity identification model. Students described a shift from solution-first thinking toward systemic inquiry, characterized mapping tools as scaffolds that externalized assumptions and structured prior knowledge, and displayed reasoning patterns consistent with adaptive transfer in the case task. These capacities did not develop uniformly: students’ accounts foregrounded structural and causal reasoning far more than reasoning about system behaviour over time, opportunity identification rarely progressed into formal opportunity development, and students were candid about where individual tools constrained their analyses. We therefore interpret systems mapping pedagogy as an amplifier of opportunity-relevant cognition rather than a direct producer of entrepreneurial outcomes. Reflecting the purposive, high-performing sample and the interview-based design, findings are offered as exploratory and bounded to this course context. The study contributes a transparent, tool-level account of how mapping practice mediates sociotechnical reasoning, a case-based transfer task with explicit criteria as a model for assessing sociotechnical learning, and design guidance for educators seeking to build sociotechnical capacity in engineering curricula. Full article

Reference building models can serve as a common baseline for research investigations and evaluations of design choices. Despite lighting being one of the largest single users of electricity in commercial buildings, lighting systems in reference buildings are commonly modeled as maximum building-type or space-type power densities defined in building energy codes. Further, energy use is typically estimated by modulating the lighting power over the course of a day via simple occupancy schedules that may not accurately portray human behavior or the performance of occupancy-based lighting controls. While this approach is suitable for some use cases, it is not adequate for exploring the impact of luminaire selection, space-specific control strategies, and occupant behavior. This paper presents the development of a high-fidelity reference model of a medium office building that includes interior architecture, an occupant distribution model, and a detailed lighting design intended to support more realistic evaluations of lighting control strategies and approaches to modeling occupant behavior. The model includes 13 market-representative LED luminaires, meets occupant lighting needs by complying with applicable recommended practices defined by the Illuminating Engineering Society (IES), and meets energy code power density and control strategy requirements in ANSI/ASHRAE/IES 90.1-2019. The luminaire-level connected load (26,037 W) of the lighting layout is lower than what would be estimated by simple building-type (34,304 W) and space-type (31,200 W) power density methods. The model includes 12 space types and 107 rooms with workstations for 268 occupants. The interior architecture varies on each of the three floors to introduce room and space-type diversity that further exposes the impact of design choices and occupant behavior. The model has already been used as a baseline for research on circadian lighting design strategies, lighting–HVAC data integration, and whole-building life-cycle assessments—demonstrating its utility as a common reference for a range of lighting research. Full article