Search Results (32,279)

This study investigates the heat transfer and fluid flow characteristics of six triply periodic minimal surface (TPMS) structures, specifically Gyroid (G3P6, G3P7, G3P8, G1P7) and Diamond (D1P7 and D3P7) configurations, using both experimental and numerical methods. Comparative analysis was conducted to evaluate the impact of adding a base to these structures on their thermal and hydraulic performance. The TPMS structures were assessed in terms of measured surface temperature, convection heat transfer coefficient, Nusselt number, overall thermal resistance, pressure drop, friction factor, and overall thermal–hydraulic performance. Results indicate that base-free structures exhibit better heat dissipation, with surface temperatures increasing by 1.2 °C (G3P6) to 5.5 °C (D3P7) when the base is added. The addition of the base reduces the convection heat transfer coefficient on average by 3.9% (G3P6) to 23% (D1P7) and increases overall thermal resistance by 3.1% (G3P6) to 28.7% (D1P7). The friction factor also rises by 6.1% (D1P7) to 47.3% (G3P6) due to the addition of the base. When the base is added, the overall thermal–hydraulic performance declines by 8.5% (G3P7) to 33.6% (D3P7), with Diamond structures experiencing a more significant reduction compared to Gyroid structures. Among the Gyroid structures, G3P6 (lower cell size and 60% porosity) demonstrated the lowest surface temperature and the highest heat dissipation capacity, while G3P8 (80% porosity) exhibited the lowest thermal performance. The Gyroid structure with larger cell size (G1P7) achieved the highest overall thermal–hydraulic performance, effectively balancing heat dissipation and fluid resistance. In contrast, when the base is integrated, the Gyroid structure with a smaller cell size and lower porosity (G3P6) showed the lowest overall thermal–hydraulic performance. Full article

Lithium slag powder (LSP), a by-product of lithium extraction, has attracted increasing interest as a supplementary cementitious material (SCM) due to its aluminosilicate-rich composition and growing availability. However, its limited intrinsic reactivity constrains direct use in cementitious systems. This study systematically investigates the effect of calcination temperature on the physicochemical properties, pozzolanic reactivity, and cement hydration performance of LSP. LSP was thermally treated at 300–900 °C, and structural and morphological changes were characterized using X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The reactivity of calcined LSP was quantitatively assessed through isothermal calorimetry (R3 test), thermogravimetric and derivative thermogravimetric analysis. Chapelle testing, leaching tests, and compressive strength measurements of cement mortars. Controlled calcination was found to enhance the intrinsic reactivity and pozzolanic activity of LSP, resulting in improved long-term mechanical performance. The findings provide mechanistic insights and practical guidance for the sustainable use of lithium slag as an SCM in cement-based materials. Full article

The structure, mechanical and electrical properties of Zr-based melt-spun Zr–(Al)–Ni–Cr–Ag alloys were investigated as a function of elemental composition. X-ray diffraction reveals the structural evolution from fully amorphous to nanocrystalline states, with the latter containing Zr₂Ni “big-cube” (space group Fd3̄m, cF96), fcc-Zr₂Ni, and β-Zr phases depending on the alloying ratio: Cr-rich compositions (≥15 at.%) stabilize β-Zr within the amorphous matrix, whereas Ag-enriched alloys promote “big-cube” phase formation. Ag atoms can replace both Zr and Ni sites in the “big-cube” lattice, yielding a (Zr,Ag)₂(Ni,Ag) solid solution and highlighting its role as a structural bridge between the amorphous and crystalline states. Nanoindentation measurements show that hardness increases from 6.5 GPa in fully amorphous ribbons to 10.12 GPa in three-phase nanocrystalline composites, with an H/E ratio of ~0.08 indicating predominantly covalent bonding, and the fracture strength of the amorphous alloys is ~2 GPa, exceeding literature values for related Zr-based systems. Electrical resistivity measurements over the 4–298 K range show that most alloys deviate from Matthiessen’s rule, exhibiting a negative temperature coefficient of resistivity consistent with the Mooij correlation; the presence of the icosahedrally ordered “big-cube” phase further increases resistivity relative to fully amorphous alloys. Full article

Tonic immobility is a state of natural paralysis that species across the animal kingdom exhibit as an instinctive response to an external threat. In ectotherms, it has been linked with temperature, but the effects of individual size, body mass and body condition are still poorly understood. We hypothesize that under natural conditions, size, body mass and body condition play an important role in tonic immobility occurrence in smaller ectothermic animals such as the Smooth newt. In this study, we photographed, measured and weighed 357 adult Lissotriton vulgaris from four populations across Bulgaria in the period December 2025–June 2026. All observed cases of tonic immobility were noted and subsequently analyzed against the effects of newt size, body mass and body condition, as well as ambient air temperature. Our results indicated that smaller newts, with lower body mass, were more prone to displaying the behaviour than larger newts, while sex and ambient temperature had no observable effects. Full article

Nuclear relaxation, $1/T_1$, is a very robust probe of electronic excitations in superconducting materials above and below the critical temperature of superconductivity, $T_{\mathrm{c}}$. Here, a relaxation phenomenology of hole-doped cuprate superconductors is presented based on the majority of the available literature data from the CuO₂ plane, without assumptions with respect to a hyperfine scenario, form factors, or particular theoretical models. Below a temperature similar to the pseudogap temperature, Heitler–Teller-type relaxation is uncovered universally; i.e., the nuclear spin relaxation above $T_{\mathrm{c}}$ is only determined by the absolute temperature, $1/T_1\propto T$. All materials condense out of this metal at $T_{\mathrm{c}}$, below which relaxation drops even faster, as expected from conventional superconductors, albeit without a Hebel–Slichter peak. It is a ’hidden metal’ in the sense that it has a vanishing uniform response and thus hardly affects the NMR shifts; it is also not seen in planar O relaxation. The hidden metal causes a temperature-independent but material-dependent planar Cu relaxation anisotropy that is strongly correlated with the size of $T_{\mathrm{c}}$. Moreover, the rate measured with the field in the CuO₂ plane is nearly the same for all cuprates: $1/{{}^{63}T}_{1\perp }T\approx 25/$Ks, where $1/{{}^{63}T}_{1\Vert }$ is mainly responsible for the change in anisotropy. Above the hidden metal, the relaxation behavior changes and can be described by an ordinary but renormalized metal, with a reduced Cu relaxation anisotropy. The relaxation phenomenology, which should hold clues to the so-called strange metal, is also discussed in the context of the two spin components previously uncovered in the shifts, as well as the pseudogap and relation to other probes. This new phenomenology should give a better foundation for the understanding of the cuprates. Full article

The corrosion behavior of N80 steel in a simulated coalbed–methane environment was investigated in a high-temperature, high-pressure autoclave. Uniform corrosion and maximum pit depth were quantified by weight-loss measurements and ultra-depth-of-field three-dimensional microscopy, respectively, while SEM, EDS, and XRD were used to characterize the morphology, elemental composition, and crystalline phases of the surface corrosion products. A one-factor-at-a-time design was applied at a constant total pressure of 10 MPa to evaluate the effects of nominal CO₂ partial pressure (0.10–1.00 MPa), nominal O₂ partial pressure (0–0.40 MPa), Cl⁻ concentration (3–187 g/L), and temperature (40–75 °C). Increasing the nominal CO₂ partial pressure raised the uniform corrosion rate from 0.712 to 0.930 mm/a but reduced the maximum pitting corrosion rate from 1.691 to 0.280 mm/a, while FeCO₃-containing surface coverage increased. Increasing the nominal O₂ partial pressure intensified both corrosion modes; at 0.40 MPa, the uniform and maximum pitting corrosion rates reached 1.446 and 2.202 mm/a, respectively, and the corrosion-product layer exhibited extensive cracking and spallation. Increasing the Cl⁻ concentration reduced the uniform corrosion rate from 1.078 to 0.839 mm/a but increased the maximum pitting corrosion rate from 0.474 to 1.807 mm/a, indicating a shift in the principal damage risk from average metal loss to localized penetration. The uniform corrosion rate reached a maximum of 1.516 mm/a at 60 °C, whereas the maximum pitting corrosion rate increased continuously to 2.202 mm/a at 75 °C. XRD identified Fe, FeCO₃, Fe₂O₃, Fe₃O₄, and FeOOH. The persistent Fe substrate reflections, interpreted together with the SEM observations, revealed spatially heterogeneous corrosion-product coverage. These results show that the protective contribution of FeCO₃-containing products depends on their surface coverage and visible integrity rather than on phase presence alone. The findings support stringent oxygen-ingress control, targeted pitting protection in high-salinity environments, and enhanced corrosion surveillance of intermediate- and high-temperature well sections. Full article

Peatlands, critical global carbon sinks, are facing increasing threats from climate change-driven heatwaves and droughts. These threats can cause a midday depression in carbon uptake through photosynthetic inhibition. Using high-temporal-resolution solar-induced chlorophyll fluorescence (SIF; ~30 s) and chamber-based CO₂ flux measurements, we investigated the coupling between SIF and gross primary production (GPP) during extreme events (air temperature > 25 °C and vapour pressure deficit > 15 hPa) in a northern peatland. Our results show that SIF tracks GPP closely under non-stress conditions (daily R² = 0.86–0.96). However, during combined heat and drought stress, midday correlations collapsed (Case A: R² = 0.04 on 27 June; Case B: R² = 0.15 and 0.01 on 29 and 30 June, respectively), indicating severe decoupling. Importantly, we discovered legacy effects from multi-day heat exposure: on 26 June, vegetation with prior cumulative stress (Case A) showed weak morning coupling (R² = 0.07), while vegetation without prior stress history (Case B) maintained strong coupling (R² = 0.93). This suggests that cumulative stress alters baseline physiology and can exacerbate midday mismatches; therefore, not just current condition controls photosynthetic regulation. These findings highlight limitations of SIF-based GPP estimation at sub-daily timescales during stress, particularly in heterogeneous peatland systems where canopy composition and physiological responses could vary among plant functional types. Full article

Existing industrial buildings represent a critical but under-addressed field for operational carbon emission reduction, as retrofit decisions are constrained by production continuity, limited investment capacity, and heterogeneous technical options. This study developed a decision support framework integrating the Decision-Making Trial and Evaluation Laboratory (DEMATEL) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) methods to evaluate and prioritize operational phase decarbonization retrofit schemes for existing industrial buildings. The framework was applied to the Thyssenkrupp S Plant in eastern China, where ten candidate schemes were identified through an energy audit, on-site investigation, and expert consultation. The results show that heating, ventilation, and air conditioning (HVAC) operational control and temperature set-point optimization ranked first, followed by lighting operational management and automatic control. These management-based measures offer strong near-term applicability because of their low investment, short payback periods, limited implementation disturbance, and immediate emission reduction benefits. Their sustained effectiveness, however, requires standardized procedures, staff education, energy monitoring, and appropriate automation. Rooftop photovoltaics provide the largest annual carbon reduction but have a lower short-term priority because of their high upfront investment. Expert-consistency testing and sensitivity analyses, including criterion weight perturbation, preference scenarios, and Monte Carlo simulation, support the robustness of the leading ranking pattern. The findings support staged retrofit planning that prioritizes durable management measures in the short term, equipment-level efficiency improvements in the medium term, and renewable energy deployment in the long term. Full article

This study presents an integrated framework for developing kinetic models of vacuum gas oil (VGO) catalytic cracking under sparse experimental data conditions. Experiments were performed in the CREC Riser Simulator at different C/O (catalyst/VGO) weight ratios. The CREC Riser Simulator is a bench-scale mini-fluidized reactor capable of reproducing the short contact times and operating conditions of industrial fluid catalytic cracking (FCC) risers. Product distributions were characterized by using a five-lump scheme consisting of unconverted VGO, light cycle oil (LCO), gasoline, light gases, and coke. To address the limitations associated with sparse datasets, a feedforward neural network (FNN) was used to reconstruct continuous reaction trajectories from discrete experimental measurements. These synthetic trajectories enabled the estimation of kinetic parameters for a phenomenological five-lump reaction network that incorporates catalyst deactivation. The resulting kinetic model established was subsequently implemented in a 1D heterogeneous model of a large-scale industrial FCC riser, providing reliable predictions of VGO conversion, product selectivity, and axial temperature profiles. Full article

Aquaculture requires continuous environmental monitoring, yet low-cost IoT sensing in marine conditions remains poorly characterised, and the data it produces is rarely accompanied by mechanisms establishing its provenance. This paper presents an IoT sensor system for marine and coastal aquaculture, comprising solar-powered 4G multiparameter nodes, a cloud-native back-end with a RESTful layer, and integration with a blockchain-based change-detection mechanism supplying a GS1-compliant digital product passport. Four nodes in adjacent cages were deployed at a marine site on the Montenegrin Adriatic for eight weeks, measuring temperature, pH, dissolved oxygen, oxidation–reduction potential and conductivity at five-minute resolution. Lacking reference instrumentation, we use agreement between nodes for validation. Temperature showed the closest cross-node agreement, with nodes agreeing to within 0.28 °C, and resolved a coherent cold, low-salinity intrusion detected simultaneously by all four nodes. The electrochemical and optical channels proved precise but not accurate: they tracked relative change coherently while their absolute values diverged, with oxidation–reduction potential moving from 9 mV of agreement to 71 mV over the following weeks. Cross-node coherence in conductivity and dissolved oxygen degraded progressively over the deployment, with no electrochemical or optical channel remaining coherent beyond roughly six weeks. Such sensors suit anomaly detection without calibration but require periodic recalibration for absolute reporting. Tamper-evident provenance is therefore necessary but not sufficient: sensor-level quality assurance is its missing half. Full article

This study presents a systematic investigation into the mechanical responses of two tungsten-based alloys—84W–11.2Ni–4.8Fe and 88W–8.4Ni–3.6Fe—fabricated via selective laser melting (SLM). Quasi-static compression tests using a universal testing machine and dynamic impact experiments employing a split Hopkinson pressure bar (SHPB) were conducted over a temperature range of 298–598 K and strain rates spanning from 1 × 10⁻³ s⁻¹ to 2.3 × 10³ s⁻¹. Both alloys exhibited significant strain-rate hardening and thermal softening effects. Based on the experimental data, a Johnson–Cook (J–C) constitutive model was established. The fidelity of the calibrated model for the 84W alloy was rigorously validated through pulsed X-ray radiography and static armor penetration tests. The SLM-fabricated 84W-shaped charge liner produced a well-collimated jet with a tip velocity of 5101.5 m/s and achieved a penetration depth of 87 mm into rolled homogeneous armor (RHA)-equivalent steel targets. Numerical simulations using the developed J–C model showed close agreement with experimental measurements, with a maximum discrepancy of only 9.19%, thereby confirming the predictive capability of the constitutive model. These results demonstrate that the proposed J–C model can reliably characterize the large-deformation behavior of SLM-processed 84W and 88W liners under the extreme thermomechanical conditions characteristic of shaped charge jet formation—namely high temperature, high pressure, and ultra-high strain rate. Collectively, this work establishes a foundational framework for the application of SLM technology to shaped charge liner design and provides a critical basis for further research into jet formation physics and penetration mechanics of tungsten-based alloys. Full article

This study investigates fire behavior and personnel evacuation safety in a nuclear chemical workshop based on the Fire Dynamics Simulator (FDS) and real fire experiment. The typical fire scenario caused by cable faults at middle distribution box locations was analyzed to evaluate the effects of ignition position on fire growth and smoke propagation. The FDS results show that the upper-layer temperature reaching approximately 180 °C at 173 s, while visibility at 2 m height decreases to 10 m at 176 s and CO₂ concentration rises to 1%. The CO concentration at 2 m reaches 500 ppm at around 290 s. The calculated Available Safe Egress Time (ASET) of 145 s exceeds the Required Safe Egress Time (RSET) of 117 s, indicating acceptable evacuation safety under this scenario. A full-scale real fire experiment was further conducted under a 5 MW fire. Temperature measurements showed that the thermocouple tree nearest the fire source reached a maximum temperature of approximately 620 °C, posing a severe threat to unprotected steel roof structures. The temperatures below 2 m remained relatively lower, decreasing from about 250 °C to 150 °C. These results demonstrate that the concentrated fire scenario primarily endangers roof load-bearing structures, whereas the thermal conditions in the evacuation zone are comparatively less severe. Full article

Cross-border trade security risks are often embedded in inconsistencies among trade documents, logistics trajectories, hardware sensor states, and financial settlement activities. Existing methods primarily rely on structured declaration fields, making it difficult to verify digital declarations against actual physical processes or to generate complete evidence suitable for regulatory review. To address these challenges, TradeSense-EQA is proposed as a cross-border trade security anomaly detection and evidence-grounded English question-answering framework. Multisource sensing information, including trade documents, GPS/AIS trajectories, RFID records, electronic seal events, port weighing data, temperature and humidity measurements, vibration signals, container door states, and visual images, is jointly modeled within the framework. The reliability-aware representation module dynamically adjusts sensing-channel weights according to data missingness, sampling intervals, device health states, and communication quality. The trade-process-constrained module identifies anomalies across declaration, packing, transportation, transshipment, arrival, and customs clearance stages and generates process-consistent evidence chains. The evidence-grounded question-answering module answers English trade risk questions on the basis of verified documentary fields and sensor records, while confidence estimation and abstention mechanisms are incorporated to reduce factual hallucinations. Experimental results demonstrate that TradeSense-EQA achieved an Accuracy of $0.918$, a Precision of $0.909$, a Recall of $0.897$, a Macro-F1 of $0.903$, and a ROC-AUC of $0.958$ on the cross-border trade anomaly detection task, outperforming baseline methods including XGBoost, LightGBM, TCN, Transformer, BERT, CLIP, and VisualBERT. On the English trade risk question-answering task, Exact Match, Token-level F1, BLEU, ROUGE-L, and BERTScore reached $0.782$, $0.851$, $0.668$, $0.801$, and $0.934$, respectively. Ablation results further confirmed the effectiveness of hardware sensing input, reliability-aware weighting, declaration–fact alignment, process-graph reasoning, and evidence-constrained generation. The proposed framework provides a reliable, interpretable, and auditable artificial intelligence-driven sensing solution for customs supervision, port security, international logistics review, and trade-background investigation. Full article

We present FDS and AERMOD simulations of the Alaska Clean Seas (ACS) oil burn experiments to improve dispersion modeling of large, open-air fires relevant to industrial settings. We propose a method in which FDS smoke fields with available ground measurements are used to empirically calibrate AERMOD configured using volume sources to represent the fire source. FDS is first run for the three ACS experiments at high resolutions (~10 m) and verified against ground monitoring to provide detailed three-dimensional smoke fields. The fractional allocation of total fire emissions (weights, w_i) is then empirically specified for each volume source i so AERMOD smoke predictions fit both the ground level measurements and FDS simulations to acceptable accuracy. Runs for volumes at the surface (i = 1), 100 m AGL (i = 2) and 300 AGL (i = 3) and w_i = [0.01, 0.09, 0.9]–[0.04, 0.36, 0.6] accurately represent these data, suggesting this range as suitable for fire heat fluxes (~800–3000 kW/m²), wind speeds (5–10 m/s) and PBL depths (300–500 m with and without capping temperature inversions) of the three ACS experimental burns. Further work exploring the applicability of this AERMOD setup to a broader range of conditions is ongoing. Full article

We demonstrate a high-power broadband continuous mode-hop-free (MHF) tunable singly resonant optical parametric oscillator (SRO). To obtain broadband continuous MHF operation, a synchronous etalon-angle locking technique and a feedback-optimized temperature controller were developed based on theoretical investigation. At a pump power of 21 W that was eight times the pump threshold, the measured signal was tuned from 1551.9087 nm to 1568.6549 nm, and the corresponding idler was tuned from 3384.3030 nm to 3307.3073 nm simultaneously. A continuous MHF tuning bandwidth of 2.064 THz was achieved at a tuning speed of 4.7 GHz/s. Continuous MHF operation in the whole tuning band was verified by high-resolution absorption spectroscopy of acetylene and methane, and by the continuous sinusoidal transmission through a Fabry–Perot etalon. The measured powers of the signal at 1560 nm and idler at 3346 nm were 4.12 W and 2.26 W with peak-to-peak fluctuations of ±0.42% and ±0.18%, respectively. These results represent, to the best of our knowledge, the widest continuous MHF tuning bandwidth achieved by a temperature-tuned SRO at high pump power, providing a high-power dual-band coherent source for precision spectroscopy. Full article