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Mini-supernovae from white dwarf–neutron star mergers: Viewing-angle-dependent spectra and light curves
No full textContext. Unstable mass transfer may occur during white dwarf–neutron star (WD–NS) mergers, in which the WD can be tidally disrupted and form an accretion disk around the NS. Such an accretion disk can produce unbound wind ejecta with synthesized 56Ni mixed in. Numerical simulations reveal that this unbound ejecta should be strongly polar-dominated, which may cause the subsequent radioactive-powered thermal transient to be viewing-angle-dependent–an issue that has so far received limited investigation.
Aims. We investigated how the intrinsically nonspherical geometry of WD–NS wind ejecta affects the viewing-angle dependence of the thermal transients.
Methods. Using a two-dimensional axisymmetric ejecta configuration and incorporating heating from the radioactive decay of 56Ni, we employed a semi-analytical discretization scheme to simulate the observed viewing-angle-dependent photospheric evolution, as well as the resulting spectra and light curves.
Results. The observed photosphere evolves over time and shows a strong dependence on the viewing angle: off-axis observers can see deeper, hotter inner layers of the ejecta and larger projected photospheric areas compared to on-axis observers. For a fiducial WD–NS merger producing 0.3 M⊙ of ejecta and 0.01 M⊙ of synthesized 56Ni, the resulting peak optical absolute magnitudes of the transient span from ≃ − 12 mag along the polar direction to ≃ − 16 mag along the equatorial direction, corresponding to luminosities of ∼1040–1042 erg s−1. The typical peak timescales are expected to be 3–10 d.
Conclusions. We present the first exploration of the viewing-angle effect on WD–NS merger transients. Since their ejecta composition and energy sources resemble those of supernovae, yet WD–NS merger transients are dimmer and evolve more rapidly, we propose using “mini-supernovae” to describe the thermal emission following WD–NS mergers. Our study highlights the critical role of geometry in the interpretation of WD–NS mini-supernovae and motivates further exploration of their diversity in observation
Research on the Influencing Factors of Non-grain Cultivation of Cultivated Land in Sichuan Province
No full textTo address the increasingly severe issue of non-grain cultivation of cultivated land in Sichuan Province, this study aims to systematically identify its key driving factors. Based on panel data from 21 prefecture-level cities across the province spanning from 2020 to 2022, a comprehensive indicator system encompassing five major dimensions—economic, demographic, production conditions, policy, and natural factors—was constructed. A multi- model cross-validation was conducted by integrating the geodetector model, panel model, generalized linear model, and geographically and temporally weighted regression model. The study revealed that the consumer price index for urban residents, the proportion of cultivated land within the cultivated land protection target, and the altitude of cultivated land exert significant inhibitory effects on non-grain cultivation. Conversely, Soil biodiversity exhibits a significant positive driving effect, which is conducive to promoting the cultivation of non-food crops. Additionally, factors such as annual precipitation and soil pH value also exhibit significant influences. The findings provide a quantitative basis for formulating differentiated cultivated land protection policies and optimizing agricultural layout in Sichuan Province. It is recommended to strengthen policy implementation and dynamic monitoring to ensure regional food security and the sustainable utilization of cultivated land
Research Advances in utilization of Feed Surplus in Pastures: From Intelligent Detection to Automatic Control
No full textIntelligent detection and control methods for feed surplus in livestock farms are summarized and evaluated in this paper. Increasing scale and intensification render traditional feeding management inadequate for modern efficiency, welfare, and sustainability requirements. Intelligent and precise feeding management has become a key direction for industry transformation and upgrading. Traditional manual inspection decisions are plagued by high labour intensity, poor timeliness, and low precision. They not only increase production costs but also trigger animal health problems and environmental pollution. These issues hinder optimal feed resource allocation. In this research, the intelligent detection and control methods for feed surplus in livestock farms were summarized and evaluated. The applications of sensor fusion, machine vision, and intelligent inspection robots in feed surplus detection, and the principles, advantages, limitations of different detection technologies were analyzed. The types, structural designs, and performance characteristics of automatic feeding actuators were discussed. The current state of farm decision-making systems and preliminary IoT system construction were briefly summarized, with emphasis on various models and methods applied in farm systems. Current limitations were generalized and future research directions including multimodal fusion, edge intelligence, and lightweight models were proposed
Adaptation aux fortes chaleurs dans l’agglomération de Sfax : mesures météorologiques et comportements de la population pendant l’été (2023-2024)
No full textLe climat semi-aride de la ville de Sfax (centre-est de la Tunisie) contraint la population à adapter ses comportements lors de la saison chaude et ses modes d’habiter pour atténuer l’inconfort dû aux fortes chaleurs. L’approche méthodologique plurielle (mesures météorologiques in situ, enquête par questionnaire et entretiens) a permis de révéler que l’ambiance thermique varie surtout en fonction de l’exposition du logement au vent rafraîchissant et à l’ensoleillement. Le calcul d’indices de confort thermique pendant l’après-midi indique un gain d’environ 6°C dans les logements exposés à l’est (à la brise rafraîchissante et à l’ombre), tandis qu’au niveau des habitations orientées au sud et au sud-ouest, la dégradation du confort thermique est expliquée par l’exposition et la faible ventilation. Pendant la saison chaude, la climatisation électrique est systématiquement utilisée, notamment dans la partie centrale de la ville, peu végétalisée, caractérisée par des logements collectifs construits en brique rouge. Hormis la climatisation, les déplacements de la population de Sfax vers les sites balnéaires au nord et au sud du pays peuvent être une autre adaptation pour échapper de la chaleur urbaine. En effet, environ 58 % des enquêtés passent leurs vacances d’été dans des sites balnéaires au nord et au sud du pays
The Impact of Green Packaging on Vietnamese Students' Green Purchase Intention: Driving Environmental Sustainability in Digital Commerce
No full textThis study explores the impact of green packaging on green purchase intention among Vietnamese students in online shopping settings, applying the Stimulus-Organism-Response Theory. It examines the mediating roles of green satisfaction and green loyalty in the link between green packaging and purchase intentions. Data were collected from 281 Vietnamese students and analysed using PLS-SEM methodology. Results show that green packaging has an indirect effect on green purchase intention through green loyalty, with both green satisfaction and green loyalty exerting significant positive influences on purchase intentions. The findings reveal that green loyalty has the strongest impact (β = 0.49, p < 0.001), followed by green satisfaction (β = 0.348, p < 0.001), while green packaging exhibits a weaker direct effect (β = 0.105, p = 0.007). These results contribute to understanding the relationship between green packaging, consumer psychology, and green purchase intention in e-commerce contexts, offering vital guidance for designing effective green marketing strategies in emerging markets
Optimization of Abaca Fiber Content in Cementitious Composites to Improve Mechanical Performance at Early and Design Ages
No full textCarbon emissions from the construction sector-particularly from cement-based concrete-remain a significant challenge to sustainable development goals. Amid decarbonization efforts, abaca fiber (Musa textilis) has emerged as a promising natural reinforcement material due to its high tensile strength, biodegradability, and availability in tropical regions. This study investigates the mechanical performance of concrete reinforced with abaca fiber at dosages of 0.35% and 0.70% by cement weight, using a mix design without chemical admixtures, a fixed water-cement ratio of 0.45, and fiber length of 3.5 cm. Compressive strength tests were conducted on standard cylindrical specimens (150x300 mm) at 7 and 28 days. Results show that both fiber-reinforced mixes improved compressive strength compared to control. The 0.70% dosage achieved the highest strength (40.45 MPa), a 15.02% increase over control, while 0.35% provided a moderate gain (+6.03%) with better mixing stability. The greater strength gain at 28 days suggests enhanced fiber bridging during hydration. These findings enrich empirical data on natural fiber-reinforced concrete and affirm the strategic role of locally sourced biomaterials in low-carbon construction, supporting circular economy principles and advancing the targets of SDGs 11 and 12
Data Center Management Planning in a Glassware Company Using the NIST SP 800-30 Method
No full textThe article describes how the NIST SP 800-30 Risk Assessment Framework is utilized in the planning of a centralized data center for a company selling glassware. The company, at present, faces a lot of operational problems of a critical nature since there is no integrated information system. These problems include incorrect inventory records and reporting delays, data flow broken among different departments, and no realtime monitoring. The risk assessment overall reveals that the study reveals medium-to-high risks like data loss, stock inaccuracies, and human error which cumulatively reduce operating efficiency and make the company hard to survive. The major groups of IT assets chosen are hardware, software, cloud systems, and human resources. The results also indicate that if a proper technological and human resources support is provided to the inventory information system along with integration, then the data will be more reliable, the reporting will be faster and the workflow through automation will be smoother to a great extent. In additions, the combination of cloud-based backup and redundancy systems ensures that the company will not only be less vulnerable to data loss but also enjoy increased business continuity. The paper maintains that adopting a systematic, risk-based approach to data center planning is tantamount to establishing a strong and efficient foundation for the company's digital infrastructure that will contain, among other things, accurate decision-making capabilities, and support the company's survival in the competition of increasingly digitalized retail environments
Application of operating systems for the combined development of ground vehicles and drones for cargo delivery based on artificial intelligence
No full textThe relevance of this study is determined by the need to improve the efficiency of international cargo delivery and the intellectualization of service markets. The methodological basis of the study consists of methods of theoretical generalization, abstract-logical method, statistical analysis, as well as a group of expert assessment methods, namely the Delphi method and the method of predictive graph with the formation of a system of interrelationships. A mechanism has been created for managing the operational systems of the combined development of ground vehicles and drones for cargo delivery based on artificial intelligence, as well as a mechanism for the combined use of ground vehicles and drones in the organization of cargo delivery. The efficiency of the delivery of groups of special cargoes using combinations of ground vehicles and drones has been assessed, which made it possible to prove the effectiveness of the proposed tools and determine the optimal options based on scenario modelling
Towards the study of the efficiency using of locomotives of electrical traction on the Kokand - Andizhan section of the Kokand branch of the railway
No full textThe subject of the study is the moving parameters of a cargo train with a constant fixed mass of the composition, organized by an electric locomotive of the Uz-EL type, and the amount of electrical energy consumed by it in conditions the energy-optimal control mode of the movement of such a cargo train. Substantiation of the main efficiency indicators of locomotives of electrical traction, taking into account the given traffic schedule with use various options for the optimal mode of controlling driving of a cargo train with the constant fixed train mass on a real flat section of Uzbekistan railway. Methods and methodology of the investigation are theoretical foundations of locomotive traction and of theories of mathematical optimization of object control, including the C# programming language taking into account the necessary programming applications in the Microsoft Visual Studio 12.0 environment. Results received from the energy-optimal curves and moving parameters of the motion of a cargo train, and the parameters of the main indicators of the energy effectiveness of the investigated electric locomotives for different options of computer calculation of cargo trains conducting (driving) modes on a real plainly of the section Kokand - Andijan of the Uzbekistan railway. The results of the study, taking into account the actual conditions of organizing cargo transportation, will ensure the rational use of electrical energy at the Kokand locomotive depot and substantiate the traction characteristics of railway areas of varying by degree complexity
A Hybrid WaterGEMS–MAE–PCC Framework for Hydraulic Modeling and Reliability Assessment of Water Distribution Systems
No full textReliable and efficient water distribution systems are vital for ensuring adequate water supply and sustainable urban development. This study focuses on the hydraulic modeling and reliability assessment of a water distribution system using Bentley WaterGEMS, hybridized with Mean Absolute Error (MAE) and Pearson Correlation Coefficient (r) for performance evaluation. The main objective is to analyze the system's hydraulic behavior—particularly pressure and flow distribution—and assess the accuracy and reliability of the simulated model compared to field data. The methodology involved the development of a detailed WaterGEMS model based on actual network parameters such as pipe dimensions, material, nodal elevations, and demand patterns. Extended Period Simulation (EPS) was conducted to capture temporal variations in system performance. Model calibration and validation were performed using observed pressure and flow data. The MAE quantified the average deviation between simulated and observed values, while the Pearson correlation measured the strength and direction of their linear relationship. Results showed that the model achieved low MAE values and a strong positive correlation (r > 0.9), indicating high model accuracy and reliability. Hence, the integration of WaterGEMS with MAE and Pearson correlation provides a robust framework for evaluating hydraulic performance. It is recommended that the calibrated model be utilized for system optimization, proactive maintenance, and strategic planning to improve the overall efficiency and resilience of the water distribution network