Search Results (37,650)

This study presents a detailed numerical analysis of impinging propane flames within confined enclosures using the Fire Dynamics Simulator (FDS, v6.5.3). Two archetypal configurations were examined: (i) free buoyant plumes in unconfined environments, and (ii) ceiling-impinging flames under both open and confined conditions. The investigation encompassed a range of heat release rates (0.5–18.6 kW) and five degrees of ventilation confinement. The simulation results confirm that FDS reliably reproduces flame height evolution under free plume conditions, exhibiting strong consistency with Heskestad’s empirical correlation and available experimental benchmarks. Under ceiling impingement, confinement markedly influences the thermal field, the distribution of major gas species (O₂, CO₂, C₃H₈), and the accumulation of unburnt gas. Distinct from previous works primarily centered on unconfined plume dynamics, the present study systematically characterizes the onset of auto-ignition through combined lower flammability limit (LFL) and auto-ignition temperature (AIT) criteria for confined propane combustion. The highest auto-ignition risk was identified in partially confined configurations (Conf. 2 and Conf. 3) at an HRR of 18.6 kW, where unburnt propane concentrations locally exceeded the LFL (≈0.2%) and ceiling temperatures surpassed the AIT of propane (455 °C). The findings elucidate critical trade-offs between ventilation and safety. They also contribute to a validated FDS-based methodology for evaluating fire-induced flow structures, combustion behavior, and ignition hazards in confined spaces. Full article

A double-staggered grating waveguide slow wave structure (DSGW–SWS) is designed for a 340 GHz traveling wave tube (TWT). Input and output couplers were also designed to isolate the electron beam source from the electromagnetic (EM) signal. Transition sections in the SWS circuits were made by tapering the height of the DSWG to improve the matching of the circuit with the couplers. The reflection coefficient has a wide range from 326 GHz to 364 GHz below −15 dB. Particle-in-cell (PIC) simulation is performed using an ideal particle source for sheet electron beam (SEB), considering the filling factor to be around 50%. The average input power of a 340 GHz signal is said to be 0.19 W, which is amplified to 17.4 W with a gain of 19.55 dB. Full article

We propose and develop a unified framework for Weyl-type symmetry in von Neumann algebras. Motivated by recent automorphism-rigidity phenomena that identify finite Weyl groups inside automorphism groups of crossed products arising from lattice actions on homogeneous spaces, we introduce the Weyl group of an inclusion $W(M;B):={\mathrm{Aut}}_B\left(M\right)/{\mathrm{Inn}}_B\left(M\right)$, for a unital inclusion $B\subset M$ of von Neumann algebras, and investigate its structure across several rigidity regimes. Our main results (1) prove finiteness or triviality of $W(M;B)$ for large classes of nonamenable crossed products, including hyperbolic and product-type actions with spectral gap and malleability; (2) establish a subgroup-normalizer rigidity principle for inclusions $L\left(\Lambda \right)\subset L\left(\Gamma \right)$ that identifies ${\mathrm{Aut}}_{L\left(\Lambda \right)}\left(L\left(\Gamma \right)\right)$ with a discrete group controlled by $N_{\Gamma }\left(\Lambda \right)$; (3) show that permutation-type symmetry for product/tensor decompositions is the only possible nontrivial symmetry of the underlying group subalgebras; and (4) extend the analysis to type III factors via Maharam extensions and unique-Cartan phenomena, proving that $W(M;B)$ is discrete and often trivial, leaving only modular flows as outer symmetries. Consequences include new computations of outer automorphism groups, constraints on intermediate subalgebras, and classification consequences for crossed products and amalgamated free products. The methods combine Popa’s intertwining-by-bimodules, spectral-gap and s-malleable deformations, boundary/ucp-map rigidity, and groupoid/Cartan techniques. Full article

Polygonum cuspidatum, a traditional medicinal plant widely cultivated in Hubei Province, China, contains resveratrol, which has been shown to regulate lipoprotein metabolism, inhibit platelet aggregation, and aid in the prevention of arteriosclerosis and cardiovascular diseases. However, conventional extraction methods are often limited by low efficiency and solvent toxicity. A novel extraction strategy integrating an ultrasound-assisted extraction with natural deep eutectic solvents (NADES) was developed to achieve environmentally friendly and effective recovery of resveratrol from Polygonum cuspidatum. The optimized NADES system consisted of betaine and DL-malic acid in a 1:4 molar ratio with 50% water content. Using single-factor experiments and Response Surface Methodology, the following parameters were identified as optimum: solid–liquid ratio, 1:28 g/mL; ultrasonic power, 240 W; ultrasonic temperature, 40 °C; and ultrasonic time, 30 min. In such a case, the resveratrol yield reached 33.12 mg/g by UV-Vis spectroscopy and 2.95 mg/g by HPLC analysis, significantly higher than that obtained by other methods. Antioxidant assays demonstrated that the extract exhibited strong scavenging activity against ABTS⁺•, DPPH•, and •OH radicals. These results demonstrate that the ultrasound-assisted extraction with NADES method provides an efficient and eco-friendly alternative for extracting resveratrol from Polygonum cuspidatum, yielding extracts with notable antioxidant properties. Full article

Estimating runoff in ungauged catchments remains a major challenge in hydrology, particularly in remote Andean headwaters where limited accessibility and budgetary constraints hinder the long-term operation of monitoring networks. This study integrates satellite-derived rainfall data, hydrological modeling, and benthic macroinvertebrate diversity analysis to explore how short-term antecedent flow conditions relate to temporal variation in community structure. The research was conducted in a pristine 0.26 km² micro-catchment of the upper Collay basin (southern Ecuador). Daily simulated discharge was used to compute antecedent flow descriptors representing short-term variability and cumulative changes in stream conditions, which were related to taxonomic (i.e., H = Shannon diversity, E = Pielou evenness, and D = Simpson dominance) and functional indices (i.e., Rao = Rao’s quadratic entropy, FAD1 = Functional Attribute Diversity, and wFDc = weighted functional dendrogram-based diversity) using Generalized Additive Models. Results showed progressively higher hydrology–biology associations with increasing antecedent flow integration length, suggesting that biological variability responds more strongly to cumulative than to instantaneous flow conditions. Among hydrological descriptors, the cumulative magnitude of negative flow changes was consistently associated with taxonomic diversity. H and E showed more coherent and robust patterns than functional metrics, indicating a faster response of community composition to short-term hydrological variability, whereas functional diversity integrates slower ecological processes. While based on modeled discharge under severe hydrometeorological data limitations, this study provides a practical ecohydrological starting point for identifying short-term hydrological memory signals potentially relevant to aquatic biodiversity in ungauged headwater systems. Full article

This study investigates viscosity-enhancing and early-strength wet-mix shotcrete (VE-ESWS) incorporating a self-developed viscosity-enhancing and early-strength agent (VE-ES). Indoor tests combined with on-site spraying were performed to quantify the effects of the water/cement ratio (W/C) and VE-ES dosage on workability, strength, and durability. VE-ES had little influence on pumpability but substantially enhanced sprayability, reducing rebound rate to below 8%. Compressive and splitting tensile strengths peaked at W/C = 0.43–0.44 and a sand rate of 55%, whereas sand rates of 50% or 60% caused noticeable reductions. Durability (water permeability, freeze–thaw resistance, wet–dry sulfate attack, and carbonation resistance) of VE-ESWS was superior to that of the reference wet-mix shotcrete. Water penetration height could be controlled to about 5 cm when W/C was 0.42–0.43. During freeze–thaw cycling, mass loss rate increased initially and then decreased; slight apparent mass gains at later cycles were attributed to moisture uptake. VE-ES effectively reduced the compressive strength loss of VE-ESWS after sulfate attack, although the mass loss rate increased rather than decreased after 100 wet–dry sulfate attack cycles. The carbonation rate of VE-ESWS decreased with increasing VE-ES dosage. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results corroborated accelerated hydration and pore-structure refinement. Based on combined indices, the recommended values are W/C = 0.42–0.44, and the VE-ES dosage = 7.5 kg/m³ within the studied ranges. This study could provide theoretical and technical support for the application of VE-ESWS in engineering practices. Full article

Heterojunctions combining graphene with transition metal dichalcogenides (TMDCs) have garnered considerable interest in phototransistor research. Molybdenum disulfide (MoS₂) can be well combined with graphene owing to its excellent and special bandgap characteristics. In this study, a photoelectric transistor is designed and fabricated based on a graphene–molybdenum disulfide (MoS₂) van der Waals heterojunction. Its novelty lies in constructing a vertical heterojunction architecture with a well-defined structure, clear interface, and easy gate modulation. It fully utilizes the high mobility of graphene and the appropriate bandgap of MoS₂ to achieve efficient light absorption and carrier transport. The device exhibits a good photoelectric response and stability at room temperature, with key performance indicators including the following: a responsivity of 0.5023 mA/W, and a dark current of approximately 10⁻¹¹ A at a gate voltage of 0 V and approaching 10⁻¹⁰ A at 30 V; when the light intensity is 1000 mW/cm², the photocurrent reaches the 10⁻⁸ A level, demonstrating the synergistic modulation capability of gate voltage and light intensity. Although its responsivity is lower than some high-performance heterojunction devices, this device has advantages such as a simple structure, controllable preparation, stable room-temperature operation, and the potential for a broad-spectrum response, showing good application prospects in flexible electronics and integrated optoelectronic systems. This study provides an experimental basis and technical path for the development of two-dimensional material heterojunctions in programmable, multifunctional optoelectronic devices. Full article

Self-powered perovskite photodiodes provide an attractive platform for low-power and high-sensitivity photodetection; however, their performance capabilities are often constrained by inefficient interfacial charge extraction and noise suppression. Here, we report a polymer-mediated interfacial engineering strategy for methylammonium lead iodide (MAPbI₃) photodiodes by integrating thermally optimized nickel oxide (NiO_x) hole-transport layers (HTLs) with a nonionic polymeric surfactant, poly(oxyethylene)(10) tridecyl ether (PTE). NiO_x films annealed at 300 °C establish a favorable energetic baseline for hole extraction, while the ppm-level incorporation of PTE into the MAPbI₃ precursor enables the molecular-scale modulation of the NiO_x/MAPbI₃ interface without forming an additional interlayer. The external quantum efficiency at 640 nm increases from 78.7% for pristine MAPbI₃ to 84.1% and 84.6% for devices incorporating 30 and 60 ppm PTE, corresponding to enhanced responsivities of 406, 434, and 437 mA/W. These improvements translate into reduced noise-equivalent power and an increase in the noise-limited detectivity from 2.50 × 10¹² to 2.76 × 10¹² Jones under zero-bias operation. Importantly, enhanced sensitivity is achieved without compromising the dynamic performance, as all devices retain fast temporal responses and kilohertz-level bandwidths. These results establish polymeric-surfactant-assisted interfacial engineering as a scalable and effective platform for low-noise, high-sensitivity self-powered perovskite photodiodes for renewable-energy-integrated systems. Full article

At the Ity gold deposit (Ivory Coast), carbonate-buffered tropical weathering fundamentally controlled the redistribution and enrichment of gold and associated metals within the Flotouo weathering profile. Primary mineralisation formed through skarn development at quartz diorite contacts, followed by mesothermal stages around 2 Ga, establishing the initial Au and trace-metal endowment. Hypogene processes alone, however, cannot explain the present distribution and concentration of Au, Cu, Mo, Bi, Sn, and W. Cenozoïc tropical weathering profoundly transformed the ores through coupled sulphide oxidation and carbonate dissolution. Oxidation of sulfides releases metals into circulating fluids. At the same time, dissolution of marble lenses buffered the pH towards near-neutral conditions, limiting long-distance metal transport and favouring local residual enrichment and secondary immobilisation. These processes, together with leaching of Ca, S, and Si, increased porosity and permeability, promoted fluid flow through karstic voids and collapse breccias. A lateritic blanket extends above the saprolitised hypogene ores. A systematic vertical mineralogical zonation developed across the profile, with goethite-dominated laterite at the top, kaolinite-rich saprolite in the middle, and smectite-bearing horizons at depth. This study highlights the key role of pH-buffered tropical lateritisation in upgrading pre-existing skarn-related mineralisation and producing atypical trace-metal enrichments in Birimian gold systems, providing a mechanistic framework relevant for regional exploration models. Full article

The rapid integration of photovoltaic (PV) generation into modern power networks introduces significant operational challenges, including intermittent power production, uneven charge distribution, and reduced system reliability in multi-battery energy storage systems. Addressing these challenges requires intelligent, adaptive, and physically consistent control strategies capable of operating under uncertain environmental and load conditions. This study proposes a Physics-Informed Neural Network (PINN)-based charge allocation framework that explicitly embeds physical constraints—namely charge conservation and State-of-Charge (SoC) equalization—directly into the learning process, enabling real-time adaptive control under varying irradiance and load conditions. The proposed controller exploits real-time measurements of PV voltage, current, and irradiance to achieve optimal charge distribution while ensuring converter stability and balanced battery operation. The framework is implemented and validated in MATLAB/Simulink under Standard Test Conditions of 1000 W·m⁻² irradiance and 25 °C ambient temperature. Simulation results demonstrate stable PV voltage regulation within the 230–250 V range, an average PV power output of approximately 95 kW, and effective duty-cycle control within the range of 0.35–0.45. The system maintains balanced three-phase grid voltages and currents with stable sinusoidal waveforms, indicating high power quality during steady-state operation. Compared with conventional Proportional–Integral–Derivative (PID) and Model Predictive Control (MPC) methods, the PINN-based approach achieves faster SoC equalization, reduced transient fluctuations, and more than 6% improvement in overall system efficiency. These results confirm the strong potential of physics-informed intelligent control as a scalable and reliable solution for smart PV–battery energy systems, with direct relevance to renewable microgrids and electric vehicle charging infrastructures. Full article

Background/Objectives: Parasporin PS2Aa1, recently designated as Mpp46Aa1, is recognized for its selective anticancer activity against various human cell lines. In this study, specific regions of the native protein were fragmented, and targeted amino acid substitutions were introduced to improve cytotoxic selectivity and potency. Methods: The modified fragments were evaluated individually and in combination with curcumin, a polyphenol with well-documented anticancer properties, and Sacha inchi-derived matrices, known for their antioxidant and antiproliferative activities. Results: Experimental results demonstrated that the substituted variant designated T104L-G108W exhibited superior anticancer activity compared to the native peptide P102-K11. Synergism assays revealed that curcumin-bioconjugated peptides were more effective against the tested cell lines, whereas combinations with Sacha inchi reduced cytotoxicity, suggesting possible interference in the mechanisms of action. Functional assays, including caspase 3/7 and 9 activation, Annexin V-Cy3 staining, and cell viability analysis with 6-CFDA, confirmed increased sensitivity in SiHa and HeLa cell lines, particularly for peptide T104L-G108W. Conclusions: Collectively, these findings support the effectiveness of a substitution-based strategy in improving parasporin fragments and underscore the therapeutic potential of peptide T104L-G108W as a novel anticancer candidate. Furthermore, this study provides preliminary evidence that natural biomolecules can be optimized through targeted modifications and rational combinations, establishing a framework for the development of sustainable and selective therapeutic approaches in cancer treatment. Full article

Photovoltaic thermal systems are capable of simultaneously generating electricity and recovering thermal energy from the rear surface of photovoltaic modules. When integrated with an air-source heat pump, the thermal energy recovered from an air-based photovoltaic thermal system can be utilized as an auxiliary heat source, thereby improving heating performance and reducing electricity consumption. In this study, a demonstration-scale performance assessment of an air-based photovoltaic thermal-assisted air-source heat pump system was conducted in a real building located in Asan, South Korea. Performance analysis was based on measured operational data collected over a one-month period in March 2024, corresponding to late-winter to early-spring conditions when heating demand was still present. During the measurement period, the average plane-of-array solar irradiance was approximately 600 W/m², with peak values reaching up to 1000 W/m². Under these conditions, the air-based photovoltaic thermal collector provided average electrical and thermal power outputs of 1.96 kW and 2.2 kW, respectively, while peak outputs reached 3.3 kW for electricity generation and 3.8 kW for thermal energy recovery. The daily thermal energy production remained relatively stable, ranging from 17.8 to 21.7 kWh. Furthermore, approximately 45–60% of the recovered thermal energy was effectively transferred to a buffer tank through an air-to-water heat exchanger, indicating stable solar heat recovery and storage performance. When the recovered thermal energy was supplied to the air-source heat pump during daytime heating operation, a preheating effect was observed, resulting in reduced electricity consumption and improved heating performance. The coefficient of performance increased from 2.24 during nighttime operation to 2.81 under solar-assisted daytime conditions, corresponding to a notable reduction in electricity consumption under solar-assisted daytime operation, compared with nighttime operation without PVT preheating. Overall, the results indicate that, under the tested late-winter to early-spring heating conditions, the integrated air-based photovoltaic thermal and air-source heat pump system can enhance heating performance and reduce electricity consumption, demonstrating its practical feasibility as a solar-assisted heating solution rather than representing generalized annual performance. Full article

During the magmatic stage, base and rarer metals segregate from silicate melts to form ore deposits. The usual case is the porphyry (PD) type (Cu, Mo, and W) above subduction zones. The metal grade increases from some ppb or ppm up to percent levels. A new type of trans-porphyry (TPD) deposits (Sn, Ta, Nb, and gems) results from large-scale shear between cratons within continental plates, internal decoupling, and vertical motion. The bulk ore generation process develops along three stages: from magma generation, emplacement, and the formation of an immiscible magmatic phase (MIP), fluids, and melt. However, in TPD, metals segregate from the crust during melting below 800 °C, biotites break down, and the melt remains below the critical point (731 °C). Fluid advection competes with chemical diffusion, yielding the required enrichment. The subcritical MIP splits into a silicate-rich and an aqueous-rich phase, which are both incompatible with each other. Granite, pegmatites, and greisen coexist in the magma chamber. Their respective extraction from a composite mush involves electron exchanges between charges, or orbitals, yielding metal oxides through chemical diffusion. In contrast, in metals (Nb and Ta) observed in pegmatites, and also in gems, electrons rearrange their electronic cloud through their polarizability. Lastly, gems independently grow under the influence of the extremely hard fluids (Li, Be, and B). Magma generation, involving the lower crust (garnet and pyroxene), results in melts that form the two observed pegmatite groups (NYF and LCT), with each being associated with alkaline (A-type) or continental (S-type) granitic melts. Full article

The increasing use of automated feedback in education highlights the need for rigorous validation of AI-based assessment tools, particularly in performance-based domains such as dance. This study examined the validity of the Real-time Augmented Feedback in Learning Tool (ReAL-T), an AI-based scoring engine designed to support screen-based learning and assessment for beginner dancers. Twelve adult beginners completed a learning protocol involving four choreographies, generating 96 recall performances. Three expert choreographers independently rated each performance on a 1–5 scale for body line and form and precision, while ReAL-T generated parallel scores using the same criteria. Inter-rater reliability among choreographers was evaluated using intraclass correlation coefficients (ICCs) and Kendall’s coefficient of concordance (W). Agreement between expert ratings and ReAL-T was examined using ICCs and Kendall’s W on a combined overall score. Expert ratings demonstrated excellent agreement across both categories (single-rater ICCs ≥ 0.85; Kendall’s W ≥ 0.87). When ReAL-T was included as an additional rater, agreement remained high (single-measure ICC = 0.84; Kendall’s W = 0.89). These findings indicate that the ReAL-T minimum viable product produces automated scores that closely align with expert judgement, supporting its use as a validated automated feedback component for beginner dance education. Full article

The technology development for the mass ceramic gas flow sensor (CGFS) adopted for harsh operating conditions is presented. The main characteristic of this technology is its simplicity and affordability for mass fast prototyping of CGFS with a limited set of technological equipment. Special attention is paid to the discussion of the technological and operational materials’ compatibility, flexibility, and speed of their processing to adapt the best mass flow sensor design option. The CGFS, designed and manufactured in just a few days, was tested in conditions close to the real ones and demonstrated the ability to measure gas flow in the range from 0.21 m/s to 1.25 m/s, with a constant power consumption of 152 mW@346 °C. Full article