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Abstract Dirichlet Problem for Elliptic System on Corner Domain
Full text linkIn this paper, we analyze abstract Dirichlet problem for elliptic system set on singular corner domain. We investigate the existence and uniqueness of strict solutions to the above problem using da Prato-Grisvard theory. The study is performed in the framework of little Hölder spaces
Development of an ANN-Driven Empirical Equation for Real-Time Prediction of Natural Gas Flow through Surface Well Chokes
Full text linkTo maximize production efficiency, natural gas flow via surface well chokes must be optimized. The nonlinear character of this flow frequently causes problems for conventional empirical correlations and mechanistic models. To accurately forecast gas flow rates using field data, this study develops an Artificial Neural Network (ANN) model that considers temperature, gas gravity, choke size, and pressures. The main innovation is that the optimized network is used to derive an exact, closed-form empirical equation, going beyond the typical "black-box" use of ANN. This equation enables the estimation of flow rate in real-time without requiring the execution of the ANN model, providing engineers with a valuable tool at present. The 5-neuron optimized ANN demonstrated remarkable accuracy, with training and testing average absolute percentage errors (AAPE) below 2% and a correlation coefficient (R) over 0.99. When tested on unknown data, the resultant equation performed well (R=0.999, AAPE=2.78%), outperforming conventional techniques in terms of generalization and predictive power. By connecting data-driven analytics with field operational realities for well management, this research represents a significant leap forward
Research on the Thermal Runaway Characteristics and Evolution of NCA Lithium-ion Cells under Transportation Vibration and High Temperature
Full text linkThis paper investigates the effects of vibration and high temperature, two typical transportation conditions, on the thermal runaway characteristics of 18650 NCA cells through simulation experiments. The aim is to explore the mechanisms by which transportation conditions affect the thermal runaway behavior and safety degradation of lithium-ion cells. The results show that both vibration and high temperature lead to slight capacity decay (a decrease of 0.49% and 0.38% respectively) and a significant increase in internal resistance (an increase of 24.59% and 20.49% respectively), thereby increasing the risk of thermal runaway. The thermal runaway venting temperature of NCA cells subjected to vibration and high temperature is raised by 12.04°C and 6.08°C respectively, with the venting time occurring earlier. The thermal stability of the cells is reduced, while the thermal runaway temperature is significantly lowered, with the vibration and high temperature samples decreasing by 40.85°C and 31.28°C respectively. The critical time is also shortened by 232s and 211s respectively, indicating that the overall thermal runaway process is significantly accelerated. Material analysis reveals that vibration causes structural fractures, while high temperature promotes side reactions in advance, both of which lead to accelerated thermal runaway reactions and intensified heat release. This is macroscopically manifested as a decrease in thermal runaway temperature and an increase in the highest temperature
Research on the Characteristics of Fire Detection and Alarm Devices Based on the Thermoacoustic Effect
Full text linkThe thermoacoustic effect can convert heat in a fire into sound energy, which has considerable application prospects in fire detection. A fire detection and alarm device based on thermoacoustic effect has been developed for building fire prevention. The main content of thermoacoustic effect is briefly introduced, and the application of thermoacoustic devices in fire detection is explained. A fire detection and alarm device based on thermoacoustic effect has been established. The total length of the entire device is 330 mm, with a uniform inner diameter of 40 mm. Finite element numerical simulation software is used to calculate and analyze detection and alarm devices. The characteristics of sound pressure level changing with the temperature difference of the heat exchanger were analyzed, and then the experimental, theoretical, and simulated sound response frequency values were calculated. Numerical simulations demonstrate the nonlinear multi field coupling characteristics in the process of thermoacoustic conversion. The established device begins to produce sound under the condition of a temperature difference of 194 ℃ in the heat exchanger, with a sound pressure level of 120 dB. Numerical simulation can better reflect the sound pressure level and frequency characteristics of the device. The distribution characteristics of flow and temperature can effectively demonstrate nonlinear dissipation properties. Thermoacoustic conversion exhibits characteristics of compression and heat transfer at a small scale. Thermoacoustic devices can convert the heat in a fire into acoustic alarm signals, and have great potential for application in the field of fire alarm in the future. This study provides new ideas for the construction of new fire alarm devices and important theoretical basis for the research of thermoacoustic alarm devices
Comparing and Evaluating Ensemble Generation Techniques from Multi-Model Climate Data for Wind Speed Projection in Rio Grande do Norte for the Present and Future
Full text linkThis study presents a comparative evaluation of ensemble generation techniques for projecting wind speed in the state of Rio Grande do Norte, Brazil, utilizing regional climate models from the CORDEX initiative. Two approaches—Arithmetic Mean (AM) and Convex Combination (CC)—were assessed for the historical period (1994–2023) and for future projections (2031–2060) under the high-emission RCP 8.5 scenario. The findings demonstrate that the AM method consistently outperforms CC, exhibiting higher correlation coefficients and lower root mean square error (RMSE) values across all subregions analyzed. Specifically, the AM ensemble achieved correlation coefficients of 0.88, 0.86, and 0.80 in the northern, central, and eastern regions, respectively, exceeding those of the CC method (0.85, 0.84, and 0.78). Relative to present-day conditions, projected future wind speeds increase by approximately 12.2% in the northern region, 23.5% in the eastern region, and 19.6% in the central region. A notable seasonal shift was also observed, with peak wind speeds occurring later in the year across all areas. These projected increases, when considered in light of the cubic relationship between wind speed and energy production, suggest that wind power potential may rise by over 40% in certain regions. It is also important to acknowledge that such results are subject to uncertainties inherent in climate modeling, including the structural differences among regional and global models and their associated physical parameterizations. Nonetheless, the projected enhancement in wind speed holds significant implications for strategic renewable energy planning in Rio Grande do Norte and reinforces the utility of multi-model ensemble techniques in climate-based energy assessments
Evaluating the Educational Impact of Studio-Based Design Methodologies in Architectural Courses
Full text linkArchitecture studios are essential in teaching design skills. Exploring how different design methodologies impact student performance helps improve education, fostering creativity, critical thinking, and better learning outcomes in architecture programs. The objective of the research is to examine the impact of various design methodologies on student achievement in architecture studios, identifying effective teaching approaches that enhance creativity, critical thinking, and overall performance in architectural education. The research involved 526 architecture students as participants. Data were collected using structured surveys to identify design methodologies and academic performance records. The software IBM SPSS Statistics version 17.0 was used to perform these statistical analyses including correlation coefficients, multiple linear regressions (MLR), ANOVA and paired t-test to examine the relationship between teaching methodologies and student achievement, providing insights into their impact on performance. Examined five factors: collaborative learning, iterative processes, instructor feedback, problem-solving skills, and time management. These factors were analyzed to determine their influence on student creativity, critical thinking, and overall achievement in architecture studio projects. The outcomes revealed a significant positive correlation among specific design methodologies and student achievement. Collaborative and iterative approaches showed the strongest impact on creativity and performance. Collaborative and iterative methodologies significantly enhance student achievement, highlighting the importance of effective teaching strategies in architecture studios.
Comparison of Volume Average and Pore Scale Methods for a Square Cavity with Thin Vertical Porous Layer under Mixed Convection Heat Transfer
Full text linkThe problem of heat and fluid flow through a vertical thin porous medium located in an open square cavity is considered. This problem is analyzed using two approaches: the Pore Scale Method (PSM) and the Volume Average Method (VAM), for different Reynolds and Richardson numbers. The dimensional and dimensionless governing equations for both methods are presented. The velocity and temperature distributions obtained from the two approaches are compared to determine the range of Darcy numbers (i.e., the number of pores in the vertical direction) for which the results of the volume average approach can be validated. The obtained results indicated a good agreement between the velocity and temperature distributions of the two methods when the number of pores in vertical direction is approximately 20. However, decreasing the number of pores from 20 to 5 increases the discrepancy between the pore scale and volume average methods. Furthermore, for a cavity with a high Richardson number, where natural convection is dominant, a difference between the results of the two approaches is observed even for porous layer with 20 pores in vertical direction. This discrepancy is attributed to the influence of the transverse velocity component within the porous layer, which was neglected in this study
Preparation of Biopesticide from Custard Apple Seeds (Annona squamosa): A Sustainable Approach
Full text linkThe escalating concerns regarding the environmental and health consequences of synthetic pesticides have driven the exploration of safer and more sustainable alternatives for pest management. This study investigates the preparation of a biopesticide derived from the seeds of Annona squamosa (custard apple), an underutilized agro-waste rich in bioactive compounds, notably annonaceous acetogenins and isoquinoline alkaloids. The developed methodology encompasses systematic seed collection, shade drying, pulverization, Soxhlet extraction using isopropyl alcohol, and solvent recovery through simple distillation. The resulting biopesticide extract exhibited potent insecticidal activity against key agricultural pests—mealy bugs (Phenacoccus solenopsis), caterpillars (Spodoptera litura), and plant lice (Aphidoidea spp)—in controlled laboratory assays. Mortality rates exceeded 80% at optimized concentrations within 48–72 hours post-application, with minimal non-target impact. The novelty of this work lies in its demonstration of a low-cost, solvent-efficient, and scalable extraction process using a common laboratory Soxhlet apparatus to produce a natural biopesticide from agro-waste, yielding ≥18% bioextract with consistent bioefficacy and >90% solvent recovery. Unlike previous studies that focused on crude methanolic or aqueous extracts, this research delivers a semi-purified formulation with confirmed stability and repeatable insecticidal performance. Additionally, comparative analyses reveal advantages over conventional synthetic pesticides in terms of biodegradability, ecological safety, and target specificity. This study highlights the immense potential of A. squamosa seeds in promoting circular bioeconomy approaches and delivering eco-friendly pest management tools, contributing significantly to sustainable agriculture and integrated pest management systems
Development of Biodiesel Production Strategies for Blending Purposes in Biorefineries: A Review
Full text linkThe rising demand for diesel fuel amidst declining fossil reserves, volatile oil prices, and stringent emission regulations has driven the expansion of biodiesel production. Biodiesel, primarily produced as fatty acid alkyl esters via catalytic transesterification of triglycerides, offers advantages over fossil diesel, including environmental friendliness, non-toxicity, and enhanced lubricity. However, its limited oxidation stability, energy density, and cold flow properties restrict blending ratios with conventional diesel to prevent engine performance issues. Alternative methods, such as hydrotreated vegetable oils (HVOs), face challenges related to hydrogen dependency and cost. This review explores current biomass-derived diesel production methods and proposes a cost-effective strategy for industrial-scale biodiesel with improved stability, energy content, and cold flow characteristics. This approach aims to enable higher blending ratios with mineral diesel, reducing dependency on finite fossil resources while promoting cleaner, renewable energy use
Ultra-Low Emission Strategies in Steel, Coking, and Cement Industries: Pathways to Decarbonization and Sustainability
Full text linkSteel, coking and cement industries make up nearly 30% of global industrial CO2 emissions and are key to becoming net-zero. Although earlier research usually looked at each industry in isolation, this paper provides an overview of ULE strategies that examines both technology and policy together across the various industries. Recent improvements in hydrogen-based steelmaking, molten oxide electrolysis, coke dry quenching, catalytic reforming coke oven gas, alternative binders for cement and carbon capture are synthesized and evaluated for capacity, costs and environmental impact.
The review uniquely compares what causes emissions in different sectors, how far away each technology is from being fully developed, how far digitization has advanced and what roadblocks stand in the way. The paper introduces new results on CO2 control, energy used in processes and marginal abatement costs to evaluate the practical feasibility of new technologies.
AI controls, modular CCUS, hydrogen infrastructure and the industrial symbiosis framework are explored in terms of how they push the sector into transformation. Ultimately, the review suggests areas of research and policy such as combining electrification and CCUS into systems, creating free-to-use lifecycle tools and reforming institutions to support ULE use in SMEs and developing areas. This review sets out roadmaps using several approaches that show how ULE strategies could be applied across hard-to-abate sectors with both technical and institutional support