Search Results (3,189)

Ground source heat pump (GSHP) systems contribute to sustainable building decarbonization while confronting two intertwined challenges: long-term ground thermal imbalance in shallow borefields and the requirement for coordinated operation between thermal systems and electrical grid dynamics. Hybrid shallow–deep borefield configurations have been proposed to mitigate thermal imbalance for sustainable geothermal resource exploitation, yet their grid-interactive demand–response potential remains unexplored. Here, we develop a coupled thermal–electrical model for a shallow–deep mixed GSHP (SDBHE) system equipped with water-tank thermal storage, validated against scaled sand-tank experiments (3.5–8.3% error), and assess its year-round performance under time-of-use electricity tariffs for a 200,000 m² residential district in cold-climate conditions. The SDBHE system reduces the required shallow borehole count by 28% and total drilling length by 22% compared with a shallow-only baseline, saving 11% on operational electricity costs over 10 years. Integrating water-tank thermal storage with a 50% load-shifting strategy yields an additional 10.9–11% cost reduction without degrading the system’s coefficient of performance. Under higher load-shifting ratios, the combined capital and operational savings reach 19–29%, with the optimal allocation assigning the incremental high-price-period load preferentially to deep boreholes (COP 6.29 versus 5.25 for shallow). These results demonstrate that integrating shallow and deep geothermal tiers with thermal storage enables both capital-efficient borefield design and economically viable demand-side grid participation. The findings are bound by the cold-climate residential context and the rule-based control scheme; field-scale validation and lifecycle cost analysis are needed to generalize the conclusions. Full article

Accurate reliability assessment of wind turbine gears is important for reducing maintenance costs and improving the sustainability of wind turbine gearbox operation. This study proposes a reliability modeling framework centered on shock–degradation dependence and a time-varying degradation failure threshold. First, a mapping relationship between shock signals and stress is established. Subsequently, a state-dependent shock-induced degradation increment model is introduced to describe the bidirectional mechanism by which shocks accelerate degradation and degradation states amplify shock-induced damage. Furthermore, a time-varying degradation failure threshold model is developed to characterize the dynamic attenuation of the gear load-bearing boundary during service. On this basis, a hybrid Copula function is employed to establish the joint reliability model. A numerical case study was conducted on the sun gear of a 2 MW wind turbine gearbox. The results show that, under the specified numerical operating conditions and model parameter settings, the proposed model under the fixed-threshold condition predicts a relative increase of approximately 6.1% in failure probability compared with the model assuming independent shock and degradation processes. When the time-varying degradation failure threshold is considered, the failure probability shows a relative increase of approximately 30% compared with that under the fixed-threshold condition. The proposed model can effectively characterize the failure evolution of wind turbine gears under complex loading conditions and provide theoretical support for predictive maintenance. Full article

Coastal humid-heat and photochemical-oxidant episodes are commonly studied through concentration estimation, leaving it unclear whether satellite observations improve warning decisions under explicit false-alarm constraints. This study introduces CoAST-EWS Japan, a six-station, validation-locked hindcast benchmark across Osaka Bay and Tokyo Bay. Models were developed using June–July 2023 data, calibrated and thresholded on August 2023 predictions, and retrospectively evaluated on June–August 2025 station-hour observations. The strong non-satellite route combines recent ground history, ERA5 meteorology, CAMS composition, and static station geometry. Adding previous-day MODIS thermal context to an otherwise identical XGBoost route increased average precision from 0.3153 to 0.3429, reduced the Brier score from 0.05032 to 0.04874, and improved recall/F1 under a validation-locked budget of 0.5 false alarms per station-day (FPDs) from 0.1864/0.2511 to 0.2402/0.3042. Japan-local calendar-day intervals supported the improvements in Brier score, recall, and F1. In a dimension-matched comparison using the same 18 MODIS variables, previous-day context increased average precision over the same-day route by 0.0378 (95% CI: 0.0144–0.0603), demonstrating that the timing advantage was not attributable to a larger satellite feature set. The MODIS increment was strongest during high-heat issue times and in Osaka Bay, and its ranking value was reproduced by a 36 h Temporal FLOW model. Matched spatial controls identified distance-based coastal context as the most stable 24 h graph component, while wind-aligned information operated as a complementary route. These results establish latency-aware MODIS thermal context as a measurable decision input for neighborhood-scale coastal compound warning. Strict station-level localization, cross-bay transfer, and forecast-consistent deployment define the next validation frontier. Full article

Background/Objectives: To inform policy making for the German breast cancer (BC) screening program, we systematically evaluated the long-term benefits and harms of extended age limits compared to the current standard of biennial mammography at ages 50–69 years using a decision-analytic approach. Methods: We developed and applied a Markov state-transition model for mammography screening in Germany to systematically assess the benefit–harm trade-offs of various screening strategies varying in age at start and end of screening as well as in screening frequency. The model was populated with international data for sensitivity and specificity of mammography along with German epidemiological, clinical and age-specific quality-of-life data. In deterministic analyses, the following outcomes were projected: detected ductal carcinoma in situ (DCIS) and invasive BC, BC-related deaths, life years (LY), and quality-adjusted life years (QALY), number of positive, false-positive, and total mammograms, overdiagnosis, and the incremental harm–benefit ratio (IHBR). Results: In the base-case analysis, mammography at ages 45–79 (annual, age 45–49; biennial, 50–79) achieved the highest gain in LY (10.0 life years gained [LYG] per 100 women) compared with current screening. Biennial mammography at ages 45–74 resulted in the highest benefits considering both life expectancy and quality of life (3.5 QALYs gained/100 women). Compared to current biennial mammography screening at ages 50–69, lowering the start age from 50 to 45 years resulted in an IHBR of 47 additional mammograms/LYG. Compared to biennial mammography at ages 45–69, biennial mammography at age 45–74 results in 96 additional mammograms/LYG. Further extended screening results in substantially less favorable IHBRs. Conclusions: Based on our results, extending biennial mammography screening to women aged 45 to 74 years may prevent additional BC deaths and increase remaining life expectancy at an acceptable benefit–harm ratio, and improve quality-adjusted life expectancy. Full article

To develop an analysis-oriented stress–strain model for prestressed fiber-reinforced polymer (FRP)-confined circular concrete, the path-dependent responses of prestressed FRP-confined concrete and actively confined concrete were systematically investigated. Existing experimental data were used to examine the applicability of the stress-path independence and strain-path independence assumptions under different prestressing methods. The filament winding method generally satisfies the stress-path independence assumption, with relative errors in axial stress mostly within 10%, whereas direct application of the actively confined concrete model to expansive-concrete method specimens results in errors close to 20%. After accounting for the initial confinement effect, these errors are generally reduced to within 10%. Strain-path comparisons further show that the prestress-induced initial lateral strain should be considered; after removing this initial strain component, the lateral strain–axial strain relationship shows strong consistency with that of actively confined concrete. Accordingly, the peak stress, peak strain, and lateral strain–axial strain relationship were modified, and a strain-controlled incremental calculation procedure was established to generate the complete stress–strain response. Validation against compiled published experimental data yielded an R² of 0.931 and a MAPE of 8.88% for compressive-strength prediction, while the predicted axial stress–strain and lateral dilation responses also showed reasonable agreement with the experimental results. The proposed model can therefore support nonlinear analysis over the complete loading range and quantitative assessment of strength and deformation for different prestress levels and FRP confinement parameters within the validated range. Full article

With the large-scale integration of high-voltage direct-current (HVDC) transmission systems, the receiving-end AC grid exhibits weak voltage-support capability. Consequently, grid-forming (GFM) battery energy storage converters are required to satisfy both current-limiting and voltage-support requirements during fault conditions. To address the challenge of maintaining GFM characteristics while limiting overcurrent, this paper proposes an improved low-voltage ride-through (LVRT) control strategy based on adaptive virtual impedance. The inherent limitations of switching-based strategies, which may cause overcurrent and instability due to control delays, are analyzed. The feasible region of the adaptive virtual impedance is determined, and a closed-loop regulation scheme based on real-time current-amplitude feedback is developed. To verify the feasibility and effectiveness of the proposed control strategy, hardware-in-the-loop (HIL) experiments are conducted, in which the proposed strategy is compared with existing current-limiting strategies. The results demonstrate that the proposed strategy limits both transient and steady-state fault currents to approximately 1.5 pu while maintaining high converter capacity utilization, with a reactive-power increment of approximately 0.8 pu. Furthermore, under different three-phase voltage sag depths and asymmetric fault conditions, the proposed strategy effectively limits fault currents while maintaining reactive power support, thereby enhancing the transient voltage-support capability of the HVDC receiving-end AC grid. Full article

This article examines how ministry formation and ecclesial leadership in the Evangelical Lutheran Church of Finland (ELCF) are being reshaped by 21st-century dynamics such as secularization, pluralism, and post-Christendom cultural change. As increasing numbers of theology students enter formation with limited prior church experience, the gap between academic theological education and pastoral vocation is widening. The article treats formation and leadership as an integrated analytical lens, showing how ministerial identity, vocational resilience, and leadership capacity emerge from shared theological and pedagogical processes. Comparative insights from Sweden, the Church of England, and Roman Catholic formation models sharpen this analysis. The study proposes a theologically grounded, contextually realistic model that links formation, leadership, and innovation in a mutually reinforcing way. Innovation is conceptualized as targeted, incremental development—deepened theological reflection, collaborative learning, and adaptive practices—rather than large-scale structural reform. This approach aims to be realistic and to increase the capacity of future clergy to lead mission-oriented ministry in complex contemporary conditions. Full article

This study examines whether the relationship between financial development and energy intensity in the European Union depends on the level of digitalization. Using a balanced panel of 27 EU member states over the period 2007–2019, we estimate two-way fixed effects models with Driscoll–Kraay standard errors and an interaction term between financial development and digitalization. The results indicate that financial development alone is not meaningfully associated with within-country variation in energy intensity. By contrast, its interaction with digitalization is negatively associated with energy intensity under the preferred Driscoll–Kraay specification, indicating that the estimated association between financial development and energy intensity becomes more negative as digitalization rises. The interaction provides the largest incremental increase in within-R² among the sequential specifications, although the absolute improvement is modest (Δ within-R² = 0.016) and its statistical significance is sensitive to country-clustered inference and country-specific linear trend controls. Renewable energy provides limited additional explanatory power without altering the main relationship. Overall, these results are best interpreted as suggestive rather than definitive evidence of a conditional association, underscoring the importance of considering digitalization when assessing the relationship between financial development and energy intensity. Full article

Accurate remaining useful life (RUL) prediction of lithium-ion batteries is critical for reliable operation of the system. The performance evolution of lithium-ion batteries shows long-range dependence and capacity regeneration. However, existing performance evolution models fail to properly consider the joint effect of long-range dependence and capacity regeneration, and consequently have a deficiency in mechanism interpretability, which may limit the prediction accuracy of RUL. To address this gap, this paper separately characterizes the degradation and regeneration processes of the discharge capacity, and proposes a novel discharge capacity evolution model incorporating fractional Brownian motion and the Poisson capacity regeneration process. For the estimation problem of the model parameters caused by the Poisson regeneration, we approximately transform the proposed model to one with independent increments according to the weak convergence theorem, and then develop a maximum likelihood estimation method. From a limit perspective and using the theory of total probability, we derive the distribution of RUL, and provide the point estimation of RUL. Finally, we utilize the data set of lithium-ion batteries produced by NASA to verify the effectiveness of the proposed method, and the mean absolute errors of the proposed method are declined by at least 24% compared to the existing methods. Full article

Background: Fragility fractures of the pelvis (FFP) are increasingly encountered in older adults, yet early deterioration is difficult to anticipate because fracture instability interacts with frailty and systemic vulnerability. We developed and validated an admission-based multimodal framework to predict 90-day treatment failure (TF90) before definitive management. Methods: This multicentre retrospective prediction study included 1684 consecutive patients aged ≥65 years with FFP treated at five tertiary hospitals. TF90 was defined as persistent fracture-related pain or immobility, delayed conversion to operative stabilisation, secondary displacement, FFP-related unplanned readmission, revision or unplanned reoperation, or all-cause mortality within 90 days. Only predictors available within 24 h of admission and before the definitive treatment decision were eligible, including CT-defined fracture morphology, frailty, clinical characteristics and routine laboratory biomarkers; DXA and specialised bone metabolism measurements were evaluated separately in an extended model. Four prespecified models were developed in 985 patients, temporally validated in 520 patients and evaluated in a completely held-out Centre E internal–external validation cohort of 179 patients, with additional leave-one-centre-out internal–external cross-validation. Results: TF90 occurred in 307 patients (18.2%) and increased from 8.1% in FFP I to 37.1% in FFP IV. Higher risk was associated with advanced age, greater frailty, impaired prefracture mobility, bilateral posterior ring injury, greater displacement, systemic inflammation, hypoalbuminaemia and renal dysfunction. In temporal validation, AUROCs were 0.732 for the simple logistic model, 0.763 for the core logistic model, 0.759 for the core random forest and 0.755 for the extended random forest. Neither greater algorithmic complexity nor specialised skeletal measurements provided reproducible incremental value. A development-derived high-risk stratum had a TF90 incidence of 32.2% and contained 70.0% of all events. At the fixed threshold of 0.209, sensitivity was 71.3%, specificity 70.0% and negative predictive value 93.1%. Conclusions: Pretreatment integration of pelvic ring mechanics, frailty and routinely available systemic biomarkers enables clinically relevant enrichment of older patients at risk of TF90. The model is best positioned to support intensified surveillance and structured reassessment rather than determine operative treatment. Independent prospective external validation, recalibration and clinical impact evaluation are required before routine implementation. Full article

The durability of alkali-activated materials (AAMs) in acidic environments is a key factor governing their suitability as sustainable alternatives to ordinary Portland cement (OPC). This study investigates the acid resistance of fly ash–slag alkali-activated mortars prepared with either seawater-based or distilled water-based activator solutions, thereby addressing the feasibility of substituting potable water in activator preparation. Eleven binder blends were tested, ranging from 100% fly ash (F100G0) to 100% ground granulated blast furnace slag (GGBS, F0G100) in 10% replacement increments, each prepared with both distilled-water (D-series) and seawater-based (M-series) activator solutions. Mortar cubes were exposed to hydrochloric acid (HCl) and sulphuric acid (H₂SO₄) after curing for 28, 60, 90, and 180 days. Durability was assessed through mass change, compressive strength retention, and ultrasonic pulse velocity (UPV), complemented by X-ray diffraction (XRD) analysis to elucidate mineralogical transformations. Results showed that acid resistance was governed primarily by binder composition: calcium-rich slag (C–A–S–H) systems deteriorated mainly by decalcification under acid exposure, whereas low-calcium fly ash (N–A–S–H) systems degraded more slowly by dealumination. Seawater activation did not significantly compromise acid resistance relative to distilled-water systems, with the two-activator series performing comparably under both HCl and H₂SO₄. Paired comparisons of the reported blend values showed small, age-dependent differences between the two-activator series: seawater activation modestly delayed strength loss under HCl at intermediate ages, while under H₂SO₄ it carried a small late-age penalty attributable to reaction of activator-derived chloride compounds with the acid; at most ages, the two series were statistically indistinguishable. X-ray diffraction showed essentially identical phase assemblages in the two series: no crystalline products formed under HCl, where an amorphous silica-rich residue accumulates on fly-ash-rich blends, whereas gypsum was the sole crystalline product under H₂SO₄, enhanced in seawater-activated fly-ash-rich blends. The findings clarify the role of marine ions in influencing acid degradation and provide guidance for designing sustainable binder systems for chloride- and sulphate-rich service environments. Overall, seawater is shown to be a viable substitute for potable water in activator preparation, retaining acid resistance comparable to distilled-water systems and supporting the development of more sustainable alkali-activated binders. Full article

The tight sandstone gas reservoir in Qingshimao gas field has the characteristics of complex gas–water distribution, low reservoir quality, low porosity, low permeability and high water saturation. Single-well productivity is low, the production and pressure decrease rapidly, the stable production period is short and economically viable development remains challenging. Therefore, considering the reservoir physical properties and development characteristics of the Qingshimao area, physical experiments and numerical simulations were conducted to investigate the reserve utilization characteristics of complex tight water-bearing gas reservoirs and to evaluate the effectiveness of CO₂ injection in restoring reservoir pressure and enhancing gas recovery after depletion. The results show that: (1) The movable-water saturation of Type I and Type II reservoirs ranged from 2 to 18% and 3–21%, respectively, while increasing water saturation reduced cumulative gas production and increased gas-flow resistance. Type III and Type IV reservoirs are limited by low permeability and fine pore throat. The movable-water saturation is less than 8% and 6% respectively under high water saturation conditions, and the gas–water flow is obviously limited. (2) Both continuous CO₂ injection and post-injection soaking can promote residual-gas recovery after depletion. Post-injection soaking prolongs the contact time between CO₂ and residual methane, whereas fractured cores exhibit more rapid pressure recovery but earlier CO₂ breakthrough. (3) Pore scale and two-dimensional visualization experiments show that after CO₂ injection, the pressure is transferred from the injection inlet to the production outlet, and the depleted low-pressure area is supplemented. The incremental recovery factor of the two-dimensional models after CO₂ injection ranged from 22.81 to 25.28 percentage points. (4) The numerical simulation results show that permeability, water saturation, and the injection and production rates jointly control pressure restoration and gas recovery during CO₂ injection. The high-permeability reservoir achieves a higher recovery factor but experiences earlier CO₂ breakthrough. High water saturation and high injection and production rates will weaken the effective sweep. In field application, the layers with good connectivity and moderate water saturation should be preferred, and the injection and production rates should be reasonably controlled to reduce the risk of gas channeling. Overall, post-depletion CO₂ injection can effectively restore reservoir pressure, mobilize residual methane, and enhance gas recovery in tight water-bearing gas reservoirs. The experimental results support post-depletion CO₂ injection as a potential approach for improving the development performance of tight water-bearing gas reservoirs. Full article

Biochar has been used to improve soils and promote sustainable agricultural development. The effects of applying different doses of biochar on soil aggregate structure and stability, aggregate-associated microbial communities, aggregate carbon fractions, and underlying mechanisms in planted forest soil ecosystems remain unclear. This study aimed to explore the effects of biochar amendment (7 years) on carbon stabilization in plantation soils. The effects of biochar application (0%, 0.5%, 1.0%, 2%, 4%, and 6%) on water-stable aggregate distribution, stability indices such as mean weight diameter (MWD), geometric mean diameter (GMD), and fractal dimension (D), aggregate-associated microbial communities (fungal and bacterial phospholipid fatty acids (PLFAs)), and carbon fractions such as soil organic carbon (SOC), easily oxidized organic carbon (EOC), dissolved organic carbon (DOC), particulate organic carbon (POC), microbial biomass carbon (MBC), recalcitrant organic carbon (ROC) and black carbon (BC) were investigated based on a seven-year in situ field experiment in a Eucalyptus plantation in northern Guangxi. The results showed that after 7 years, biochar application significantly increased the proportion of macroaggregates (≥0.25 mm). The MWD and GMD increased significantly with increasing biochar application rates, whereas D decreased significantly, indicating enhanced soil structural stability. Biochar significantly increased the abundance of fungi and bacteria across all aggregate size classes and changed the microbial community structure towards conditions that promoted increased carbon stabilization. Additionally, biochar application significantly increased both recalcitrant (ROC and BC) and labile carbon (EOC, POC, DOC, and MBC) in all aggregate fractions, with the largest increments in macroaggregates. Based on correlation analysis and structural equation modeling (SEM), we speculated that biochar might enhance the physical protection and chemical sequestration of organic carbon by optimizing the physical structure of the aggregates and synergizing with the microbial carbon pump. The 7-year application of biochar significantly enhanced the SOC content in plantation soils, primarily by increasing recalcitrant organic carbon, demonstrating that biochar application constitutes a viable approach to augmenting persistent soil carbon stabilization in plantation ecosystems. The 4% and 6% treatments produced the largest responses for most of the measured indicators, underscoring the importance of biochar application. Full article

Background/Objectives: Liver cirrhosis (LC) is a major cause of morbidity and mortality requiring continuous monitoring and early recognition of clinical deterioration. Home telemonitoring is increasingly considered a supportive strategy for outpatient hepatology care; however, patient acceptance remains insufficiently characterized in Eastern Europe, and no validated instrument currently exists for this population. This study aimed to develop and provide the initial psychometric validation of a Technology Acceptance Model (TAM)-based questionnaire assessing acceptance of home telemonitoring among patients with LC. Methods: In this prospective cross-sectional study, 130 adult patients with LC (Child–Pugh A/B/C) were enrolled. A 25-item questionnaire, including 13 Likert-scale items mapped to Perceived Usefulness (PU), Perceived Ease of Use (PEU), and Intention to Use (ITU), was administered under supervision. Psychometric evaluation included internal consistency, exploratory and confirmatory factor analyses, structural equation modelling (SEM), convergent and discriminant validity, and known-groups validity. Results: Internal consistency was excellent (Cronbach’s α = 0.934; McDonald’s ω = 0.950). EFA identified a 2-factor structure explaining 77.9% of the variance, whereas CFA supported the theoretically driven 3-factor TAM, which showed improved incremental fit (CFI = 0.927; TLI = 0.908) and was retained on theoretical grounds. SEM confirmed the TAM pathway, with PU strongly predicting ITU (β = 0.823, p < 0.001), whereas PEU significantly influenced PU (β = 0.343, p < 0.001) but not ITU directly. The model explained 69.5% of the variance in ITU. Known-groups validity was supported across digital access, IT comfort, education level, and disease severity. Patients with advanced cirrhosis and lower digital confidence showed lower acceptance scores. Conclusions: The proposed 13-item Likert scale demonstrated good initial psychometric performance and may represent a useful tool for assessing telemonitoring acceptance and readiness for digital monitoring among patients with LC. Pending further multicentre validation and assessment of predictive validity, the instrument may support identification of patients requiring additional support for successful telemonitoring adoption. Full article

In the development of carbonate reservoirs via water flooding huff-n-puff, the osmotic pressure effect is frequently overlooked, and existing models inadequately quantify the matrix imbibition and oil expulsion driven by salinity gradients. To address this issue, this study establishes a coupled oil–water two-phase huff-n-puff flow model for carbonate reservoirs that incorporates the interplay between salt concentration and osmotic pressure, which, for the first time, fully couples the van ’t Hoff osmotic pressure equation with solute transport equations for fractured-vuggy carbonate huff-n-puff, filling the gap that prior tight/shale reservoir low-salinity flow models fail to adapt to cyclic injection-soaking production regimes of carbonates. Based on the IMPES (implicit pressure–explicit saturation) numerical simulation method, an equivalent single-nucleus model is adopted to characterize the fractured-vuggy reservoir architecture. The model integrates the osmotic pressure formula, solute transport equation, and two-phase seepage governing equations, enabling a systematic analysis of the mechanisms by which osmotic pressure affects the multi-stage seepage process and the influence of key parameters on development performance. Quantitative simulation reveals three core laws controlled by salinity-induced osmosis: first, osmotic pressure drives water molecules to spontaneously migrate from the high-permeability fracture inner core toward the tight matrix pores, thereby modifying the water saturation distribution, expanding the water sweep region, and smoothing the saturation gradient between the inner and outer cores, which effectively mitigates water channeling in fractured reservoirs. Under the base case (injected water salinity = 1000 mg/L, inner-core permeability = 1000 mD, shut-in time = 80 d), the oil recovery factor with osmotic pressure considered reaches 13.46%, representing a 3.50% increment over the case without osmotic pressure. The recovery factor decreases monotonically with increasing injected water salinity, while it increases with longer shut-in time and higher inner-core permeability, both exhibiting pronounced diminishing marginal returns; the optimal shut-in time is approximately 80 d under the simulated conditions. This work delivers a fully coupled numerical tool and quantitative evaluation standard for osmotic imbibition mechanisms in fractured-vuggy carbonates. The quantified recovery increment and optimal soaking window established herein can directly guide field parameter optimization of injection water salinity, shut-in cycle and fracture reconstruction scale, balancing oil increment revenue and water treatment/well shutdown operation costs for on-site low-salinity huff-n-puff design. Full article