Search Results (11,113)

Poly(ethylene oxide) (PEO)-based solid polymer electrolytes are regarded as highly promising solid electrolyte materials owing to their favorable chain flexibility. However, their practical application is hindered by low room-temperature ionic conductivity and poor mechanical properties. To address these issues, a metal–organic framework (Cu-MOF) with a 2D layered structure and 1D microchannels is introduced into PEO to form a composite solid electrolyte. The results reveal that Cu-MOF can suppress PEO crystallization through steric hindrance and coordination interactions, thereby increasing the fraction of the amorphous phase. Moreover, its unsaturated metal sites can attract TFSI⁻ anions, promoting the dissociation of the sodium salt and enhancing sodium-ion transport. Theoretical calculations and molecular simulations further confirm the regulatory role of Cu-MOF in ion transport. Leveraging this mechanism, the Na₃V₂(PO₄)₃/C|PCM-8%|Na cell delivers exceptional electrochemical performance over a wide temperature range. At room temperature, the capacity exhibits virtually no decay after 200 cycles at 0.5 C, and outstanding rate capability is maintained even at a high rate of 4 C. At a temperature of 65 °C, a capacity retention of 91.4% is achieved after 200 cycles at 0.5 C. This study offers a highly promising strategy for the development of wide-temperature-range, high-performance solid-state sodium batteries. Full article

The water use efficiency (WUE) in North China is undergoing rapid changes due to climate warming and vegetation “greening”, significantly impacting the ecosystem’s carbon and water cycles. Existing research lacks quantitative analysis of WUE or an understanding of future trends. This study selected the rapidly greening Agro-Pastoral Ecotone of Northern China (APENC) as a case study, utilizing linear regression, Hurst index analysis, and residual analysis to analyze the past and future changes and driving mechanisms of WUE. The results indicated that: (1) The multi-year (2001–2023) annual mean WUE in the APENC spatially ranged from 0.32 to 2.50 g C kg⁻¹ H₂O. (2) Gross primary productivity (GPP), evapotranspiration (ET), and WUE showed significant increasing trends of 10.22 g C m⁻² yr⁻², 5.62 kg H₂O m⁻² yr⁻², and 0.01 g C kg⁻¹ H₂O yr⁻¹, respectively. (3) Precipitation had highly positive impacts on GPP and ET, while non-climatic factors (land use, human activities, etc.) explained 62% of WUE variations in the APENC, and energy conditions (air temperature and solar radiation) were not the decisive factor of WUE. (4) The Hurst exponent of WUE indicates that WUE in the APENC region generally exhibits anti-persistent behavior. In terms of future trends, WUE is projected to shift from rising to declining in 58.9% of the region, while 28.5% is expected to continue increasing. Full article

Flexible electronics require thermal-management materials that can efficiently dissipate heat while maintaining mechanical compliance under deformation. In this study, a topology-optimized kirigami BNNS/PVA composite film was developed by combining boron nitride nanosheet incorporation, electrospinning, and thermo-mechanical topology optimization. The electrospun BNNS/PVA network enhanced the in-plane thermal conductivity from 0.19 to 4.63 W/(m·K), while the optimized kirigami architecture improved deformation accommodation by reducing elastic strain energy accumulation. The average temperature and total elastic strain energy were reduced from 86 °C to 53 °C and from 43 J to 11 J, respectively. The optimized structure achieved a maximum stress of 2.39 MPa and a maximum strain of 5.02% and reduced the steady-state temperature by up to 21.27 °C under identical heating conditions. Furthermore, in-plane thermal conductivity was maintained after 300 bending cycles, which provides an effective material–structure design strategy for flexible electronic thermal management applications. Full article

3D-printed geopolymer mortars (3DPGPMs) are emerging as low-carbon construction materials that combine digital fabrication with alkali-activated binder technology. However, their hardened performance remains difficult to assess because it is controlled not only by geopolymer chemistry but also by printing parameters, rheological evolution, curing conditions, interlayer bonding, pore structure, and loading direction. This review critically examines the current literature on extrusion-based 3DPGPMs, with emphasis on mechanical properties, durability, sustainability, standardization, and practical implementation. The reviewed studies show that precursor type, activator system, aggregate/binder ratio, additives, printing conditions, and curing regime strongly influence compressive, tensile, flexural, interlayer bond, and anisotropic mechanical responses. Durability performance is also governed by the coupled effects of matrix chemistry and printing-induced features, including interlayer voids, directional pore networks, weak interfaces, and transport pathways that may affect shrinkage, water absorption, chloride penetration, carbonation, acid and sulphate resistance, freeze–thaw response, and elevated-temperature behavior. From a sustainability perspective, the environmental benefits of 3DPGPMs are conditional and depend on activator production, precursor availability, curing demand, transport distance, life-cycle assessment boundaries, and field-scale implementation conditions. The review identifies that the main knowledge gap is the limited availability of integrated datasets linking fresh-state rheology, interlayer quality, multi-scale porosity, mechanical anisotropy, durability indicators, and structural-scale validation. Future research should therefore prioritize standardized reporting, performance-based acceptance criteria, long-term exposure testing, field-scale validation, and predictive material–process–durability models. Overall, this review provides a hardened-performance-oriented synthesis to support the development of reliable, durable, and sustainable 3DPGPMs for construction applications. Full article

The Philippine Sea Basin is one of the world’s largest marginal sea basins, and the spatiotemporal variation characteristics of its sound speed field hold significant importance for deep-sea navigation and positioning as well as underwater acoustic detection. This study investigates the sound speed field in the central Philippine Basin (130.0–134.0° E, 17.5–20.5° N) using the Global Ocean Physics Analysis and Forecast product from the European Union’s Copernicus Marine Environment Monitoring Service (CMEMS), cross-validated with the U.S. HYCOM (Hybrid Coordinate Ocean Model), and independent verified against 69 Argo profiles. We systematically investigate the spatiotemporal variation characteristics of the sound speed field in this region. Temperature and salinity consistency between the two products is established (deviations of <0.5 °C and <0.05 ppt below 400 m), with CMEMS selected as the primary data source for its higher accuracy and greater temporal stability. Three sound speed formulae—Del Grosso, Chen–Millero, and TEOS-10—are intercompared, with TEOS-10 yielding the highest accuracy in cross-validation; it is therefore recommended for its rigorous thermodynamic consistency. Vertical sound speed profiles are evaluated using bi-exponential, Munk canonical, and fourth-order polynomial models. Among them, the bi-exponential model achieves the optimal balance between physical interpretability and fitting accuracy (RMSE = 2.77 m/s, inter-monthly correlation coefficient = 0.857). Its two exponential decay scales characterize the upper-ocean thermocline and the deep stratification, respectively, avoiding the physically unrealistic deep-water fluctuations exhibited by the polynomial model (RMSE = 2.68 m/s) and the poorer generalization of the Munk model (RMSE = 2.97 m/s). Horizontal gradient analysis reveals a cross-directional correlation of approximately 0.5 between sound speed gradients and ocean currents, reflecting the combined modulation of sound speed gradients by Kuroshio advection and thermodynamic stratification. The general gradient control scale is estimated at approximately 100 km × 100 km, confirmed by cross-method consistency between K-means and Gaussian mixture model clustering. Temporal analysis demonstrates that sound speed peak-to-peak variation attenuates rapidly with depth (from ~8.9 m/s at 50 m to <0.1 m/s at 4000 m), and EOF (empirical orthogonal function) analysis reveals that the first four modes explain over 99% of the total variance, with harmonic fitting identifying annual and semi-annual cycles as the dominant periodic components. Sound channel axis depth varies seasonally between 900 and 1125 m (deeper in winter, shallower in spring), with axis sound speed stable at 1480–1484 m/s (slightly higher in winter, slightly lower in spring) and axis thickness ranging from 225 to 450 m (wider in winter, narrower in spring). These results provide prior critical constraints for underwater acoustic positioning, AUV navigation, and long-range sound channel communication and navigation in the central Philippine Sea region. Full article

The article addresses the problem of estimating the specific electric energy consumption of urban electric transport under real operating conditions. It is substantiated that standardized driving cycles and rated energy consumption values do not always accurately reflect the actual operating modes of vehicles on urban routes, since energy consumption is affected by speed conditions, road conditions, passenger load, ambient temperature, auxiliary systems operation, and the number of stops, accelerations, and braking events. A simplified engineering model is proposed for adjusting the baseline specific electric energy consumption by means of a system of correction factors, which makes it possible to adapt the calculation to specific operating conditions under limited availability of telematics data. A distinctive feature of the proposed approach is the possibility of using a baseline energy consumption value determined from a driving cycle or vehicle specification data, followed by its adjustment according to the characteristics of an actual route. The proposed methodology was experimentally verified using certified trolleybus test data representing a vehicle with characteristics similar to a 12 m urban battery electric bus; however, further validation using dedicated battery electric bus datasets is required. For the reference vehicle operating on route No. 15 in Lutsk, with a route length of 10.2 km, the calculated electric energy consumption was 17.853 kWh at full mass and 12.498 kWh at curb mass, corresponding to approximately 1.75 and 1.23 kWh/km, respectively. The results were compared with experimental data and recent literature sources. The proposed methodology is intended for preliminary engineering assessment of electric energy consumption when detailed operational data are unavailable. Full article

Reliable remaining useful life (RUL) estimation is important for the safe and efficient use of lithium-ion (Li-ion) batteries in electric vehicles (EVs) and energy-storage systems. Most data-driven RUL models are trained under controlled laboratory conditions, but their performance can weaken during field operation, where usage, sensing quality, and degradation paths are less predictable. This study proposes a physics-informed laboratory-to-field (L2F) deep learning framework for battery RUL prediction under limited or unavailable target labels. The framework combines three components: a six-channel laboratory cycle representation comprising voltage, current, temperature, cumulative charge throughput, cumulative energy throughput, and voltage derivative; a gated Transformer–Temporal Convolutional Network (TCN) Fusion backbone for modeling long-range and local degradation patterns; and a staged adaptation policy based on paired-view consistency and covariance alignment. The Fusion backbone achieved the lowest held-out XJTU laboratory root mean square error (RMSE) of 46.67, compared with 48.27 for TCN and 48.85 for the Transformer. In the Tsinghua University (Tsinghua) deployment experiment, measured target RUL labels were unavailable after preprocessing and window construction. Therefore, the direct field-side mean absolute error (MAE), RMSE, and coefficient of determination $R^2$ were not computed. The Tsinghua results are interpreted as an unlabeled deployment-credibility and trajectory-regularity assessment, showing operational continuity, finite vehicle-specific predicted trajectories, and reduced local trajectory volatility after staged adaptation. The S2a + S2b policy reduced Fusion RUL volatility from 8.376 to 0.632. In the XJTU laboratory source representation, Integrated Gradients showed that physics-aware channels contributed 30.98% of the attribution mass, increasing from 19.50% in early-life windows to 31.86% in late-life windows. These attributions explain the laboratory six-channel waveform model and are not used as direct evidence of Tsinghua field-feature importance. Full article

Bamboo shoots, as the most nutritionally valuable food source for giant pandas during key reproductive seasons, are critical for conservation because their availability and timing directly influence panda foraging and habitat use. However, the molecular mechanisms through which altitudinal temperature variation governs rhizome shooting in staple food bamboos remain largely unknown. Here, we performed integrated metabolomic and transcriptomic analyses of Fargesia rufa rhizomes collected along an elevational gradient (1000 m, 1500 m, and 2000 m), with a critical paired comparison at 2000 m between a non-shooting cold gully-edge site (16.4 °C) and a shooting warm gully-center site (21.1 °C), where soil temperature is elevated by approximately 4 °C due to prolonged solar exposure. Our results demonstrate that soil temperature, rather than elevation per se, acts as the primary driver of rhizome shooting, with an apparent threshold near 20 °C. A core shooting metabolome (CSM) comprising 843 metabolites was consistently accumulated across all shooting conditions, which featured gibberellin/auxin precursors, TCA cycle intermediates, and phenylpropanoid compounds. Correspondingly, a core shooting transcriptome (Rh_shooting) of 10,970 genes was identified, which resolved into three functionally distinct temporal clusters: “shooting-on” (activated upon threshold crossing, enriched in hormone signaling and cell wall metabolism), “temperature-dose” (progressively upregulated with rising temperature, enriched in energy metabolism and defense), and “microenvironment-enhanced” (specifically upregulated in the high-elevation warm gully, enriched in photosynthesis and antioxidant pathways). Integrative network analysis further revealed zeatin riboside and multiple hub genes as central coordinators linking hormone signaling, energy metabolism, and cell wall remodeling. Collectively, these findings establish a molecular framework linking altitudinal temperature variation to bamboo rhizome regeneration—a process that directly determines the spatiotemporal availability of bamboo shoots for giant pandas. This work provides mechanistic insights into giant panda foraging ecology and has direct implications for predicting habitat quality under climate change and informing evidence-based conservation strategies for this flagship species and its critical food resource. Full article

Biogenic volatile organic compounds released from soil (SBVOCs) are an important component of the material exchange and information transmission between terrestrial ecosystems and the atmosphere. Soil ecosystems act as both critical sources and frequently overlooked sinks of BVOCs. SBVOC emissions are mainly regulated by the temperature, moisture, and pH of the soil. Climate warming may enhance volatilization and microbial production in the short term. However, its long-term effects depend on drought, vegetation composition, substrate availability, permafrost thaw, and microbial acclimation. SBVOCs also influence microbial activity, nutrient cycling, plant–microbe interactions, plant defence, and below ground trophic interactions, although the strength of evidence differs among these functions. Ecologically, SBVOCs promote carbon cycling, modulate plant-microbe interactions, and influence atmospheric chemistry. This review further synthesizes SBVOC emission and uptake patterns across different climatic zones. Several challenges remain, particularly the scarcity of long-term quantitative measurements and difficulties in distinguishing multiple emission sources. Our understanding of rhizosphere interactions and climate-change feedback is also limited. It is essential to enhance long-term observational studies and optimize models to deepen our understanding of the role of SBVOCs in the global carbon cycle and air quality. Full article

Integration of composites into the fabrication process of structural assemblies within the aerospace, automotive, marine or civil engineering industries represents a rational solution adopted by leading companies which are guided by the necessity for novel low-weight, high-strength, and high-stiffness materials. During the manufacturing process and throughout the service life, fiber-reinforced polymer structures are subjected to impact loading, either accidentally or as an inherent requirement of the operational cycle. Firstly, general aspects regarding impact loading and some parameters used for its characterization are briefly described. Recent progress regarding the influence of the stacking sequence, fiber type, and impactor geometry on the impact performance of Kevlar and glass fiber reinforced composite materials is emphasized. Additionally, the effects of environmental factors (such as temperature, UV radiation, or humidity) on the impact energy absorbed by polymers reinforced with each of the two types of synthetic fibers are presented. Finally, the importance of directing the researcher’s judgment towards improving the characteristics of materials subjected to impact, from a sustainable perspective, is motivated through the presentation of the impact behavior of polymer composites reinforced with Kevlar fibers or glass fibers hybridized with vegetable fibers. Full article

Efficient irrigation management requires complementary information on atmospheric demand, soil conditions, and crop water stress. This study presents a low-power Internet of Things (IoT)-based irrigation system that integrates these components within a unified monitoring and control framework. The system combines LoRa communication, ESP32-based sensor nodes, soil and meteorological sensing, FAO-56 reference evapotranspiration ($E{T}_0$), and canopy-temperature-based Crop Water Stress Index (CWSI). Irrigation decisions rely on the complementary use of $E{T}_0$, in situ soil measurements, and CWSI rather than on a single indicator. A hybrid time-, event-, and query-driven acquisition strategy was implemented to adapt node activity and limit communication overhead. The system was deployed under outdoor conditions in Oujda, Morocco, demonstrating integrated sensing, wireless data transmission, crop-stress monitoring, and automated irrigation control. Energy characterization further showed distinct consumption profiles across sensing, communication, actuation, and low-power operating states, supporting the use of duty cycling to limit active node operation. The results demonstrate the feasibility of integrating environmental, soil, and crop-level information within a low-power IoT framework for adaptive irrigation management. Full article

The development of biodegradable polymer composites from renewable resources is important for reducing dependence on petroleum-based plastics and improving the sustainability of short-life-cycle products. However, poly(butylene succinate) (PBS)/poly(lactic acid) (PLA) blends are generally immiscible, and the reinforcing effect of alkali-treated hemp stem fiber (HSF) on their mechanical, thermal, rheological, morphological, and biodegradation behavior remains insufficiently understood. This study investigates PBS/PLA biocomposites prepared at fixed blend ratios of 90/10 and 80/20 wt.% and reinforced with 5–20 phr alkali-treated HSF. Hemp stem fibers are treated using 5 wt.% NaOH, dried, sieved, and compounded with PBS/PLA blends in an internal mixer at 190 °C and 50 rpm for 15 min, and fabricated by hot compression molding at 190 °C for 13 min. The incorporation of HSF improves composite stiffness, with the highest Young’s modulus of 306 MPa observed for the 80/20/15 composition, representing a 71% increase over neat PBS. The maximum flexural strength reaches 48 MPa for 90/10/20, while the highest flexural modulus reaches 1377 MPa for 80/20/20, representing improvements of 21% and 77%, respectively. In contrast, tensile stress at break and elongation at break generally decrease with HSF incorporation because localized fiber agglomeration, incomplete matrix wetting, and interfacial gaps limit effective stress transfer, particularly at higher HSF loadings. The MFR exhibits composition-dependent, non-monotonic behavior. The addition of PLA initially increases the MFR relative to neat PBS, whereas higher HSF loadings generally reduce the MFR due to restricted polymer chain mobility and increased resistance to melt flow. FT-IR results indicate no strong chemical interactions among PBS, PLA, and HSF, while DSC shows nearly unchanged melting temperatures but composition-dependent changes in PBS crystallinity and crystallization behavior. FESEM confirms a phase-separated PBS/PLA morphology with embedded HSF. Soil burial tests show increased weight loss with higher HSF content and exposure time, confirming enhanced biodegradation. Full article

Dielectric capacitors are employed in defense and automotive applications owing to their ultrahigh charge–discharge rates. To mitigate the high leakage current density of Na_0.5Bi_0.5TiO₃ (NBT), SrTiO₃ (STO), which exhibits excellent insulation performance, is incorporated into the NBT lattice to enhance both the breakdown field strength and the relaxor characteristics. Furthermore, the ionic radius of Sr²⁺ (0.1180 nm) is slightly larger than the average ionic radius of (NaBi)²⁺ (0.1025 nm). As a result, the introduction of STO induces lattice distortion, disrupts long-range ordering, and promotes the formation of short-range ordered domains, thereby strengthening the relaxor behavior (the relaxation degree γ increased from 1.63 to 1.84). Consequently, the 0.95(Na_0.5Bi_0.5)(Fe_0.02Ti_0.99)O₃-0.05SrTiO₃ thin film achieves a recoverable energy storage density (W_rec) of 43.88 J/cm³ and an efficiency (η) of 73.95%. In addition, the thin film exhibits excellent temperature stability over a range of 10 to 170 °C, good frequency stability from 0.1 to 2.0 kHz, and robust fatigue endurance up to 1 × 10⁸ switching cycles. This work provides reliable technical and theoretical guidance for the application of NBT-based materials in energy storage. Full article

Earth’s rotation produces day and night cycles that are a primary selective pressure driving the evolution of endogenous circadian clocks. Cyanobacteria are the most studied prokaryotic model, and their timekeeping core is a protein oscillator composed of KaiA, KaiB, and KaiC. This oscillator sustains a near-24 h rhythm independently of transcription–translation feedback, challenging the long-standing assumption that prokaryotes merely respond passively to environmental cues. Moreover, it offers unique insights into the evolution and operational logic of circadian clocks. This review summarizes advances in cyanobacterial circadian research. We first analyze the KaiABC oscillator’s molecular basis, including synergistic conformational changes, phosphorylation and dephosphorylation cascades, and temperature compensation, which confer robustness and tunability. We compare oscillator compositions across cyanobacterial lineages, showing evolutionary plasticity. We then outline input and output networks, clarifying how environmental signals reset the oscillator phase and how temporal information is relayed to downstream processes. We further explain how the clock coordinates photosynthesis, nitrogen fixation, respiration, and cell division through predictive regulation, temporal decoupling, and resource prioritization, thereby resolving metabolic conflicts and enhancing fitness under light and dark cycles. This framework provides a theoretical basis for microbial survival strategies in fluctuating environments and offers insights for synthetic biology circuit design. Finally, we discuss open questions, including coupling between the oscillator and the cell cycle, functional divergence among ecotypes, and roles at the community level. Further research on the cyanobacterial clock will help clarify general principles of biological timing and its evolutionary origins. Full article

In human medicine, homocysteine, a sulfur-containing amino acid, is used as a biomarker reflecting endothelial dysfunction, inflammation, thrombogenesis, oxidative stress and cardiovascular disease. An automated enzyme-cycling assay for homocysteine, established for humans, has been validated and reference ranges have been created for horses. In this study the homocysteine assay was further evaluated by assessing short-term stability (whole blood and plasma samples stored at 4 °C and room temperature for 24 h), long-term stability (two years), the effect of different anticoagulants (lithium heparin, sodium citrate, EDTA, no additives) and repeated freeze–thaw cycles (five times). Further, associations between plasma homocysteine concentrations ([HCY]_p) and echocardiographic variables of left heart size, left heart function, and left-sided valve regurgitation were investigated. Homocysteine concentrations remained stable in whole blood at room temperature for at least four hours, or longer when plasma is separated and kept at 4 °C. Samples could be collected in serum blood tubes, lithium heparin (LH), or EDTA without affecting homocysteine concentrations ([HCY]). Plasma [HCY] in frozen samples increased slightly with storage time (years), though up to five freeze–thaw cycles did not affect [HCY]_p. In a cohort of 169 horses with left-sided valvular regurgitation, plasma creatinine concentrations and age were positively associated with higher [HCY]_p, but no association between [HCY]_p and changes in cardiac size, function or severity of valvular regurgitation could be established. Homocysteine is not associated with left-sided valvular heart disease in horses and is not a useful biomarker for structural or functional cardiac changes. Full article