Heming Jia, Marjan Kordani, Iman Ahmadianfar
et al.
Precise forecasting of water quality indices (WQI) is essential for safeguarding ecosystems, human health, and sustainable water resource management. This study presents an innovative approach for evaluating river Water Quality Indices using advanced machine learning methods. The approach combines the least squares support vector machine (LSSVM) with the Sherman–Morrison–Woodbury (SMW) formula and local weighting techniques to improve the model's capacity to identify local trends and nonlinearities. The hybrid model, SMW-LSSVM-R, integrates the advantages of SMW-LSSVM with ridge regression to provide a balanced and resilient predictive framework. The model parameters are improved by a self-adaptive teaching-learning-based differential evolution (SATLDE) method, attaining optimal performance. Additionally, SATLDE is combined with a ridge feature selection model to identify the key input factors and boost accuracy. The model also employs optimized multivariate variational mode decomposition (OMVMD) using SATLDE algorithm to more effectively assess complex data patterns. When the models were tested at two Iranian stations, Farisat and Molasani, the SMW-LSSVM-R model with a testing R value of 0.975 and an RMSE of 0.990, exhibited better performance than the basic and OMVMD-enhanced models. These findings demonstrate the potential of the proposed hybrid model to offer valuable insights into environmental monitoring and management.
Andrew H. Hunter, Nicholas Smith, Paulo R. P. Santiago
et al.
Background/Objectives: Passing is the most frequent and impactful action in soccer. It requires players to control the ball and pass accurately with either foot, make quick decisions, and scan the field while under pressure. Using a recently developed series of passing tests that vary in complexity and scanning demands, we examined how a player’s choice of technique when controlling and passing the ball, along with their ability to scan effectively, influenced passing performance. Methods: Forty-five elite U12 and U13 players from a Brazilian academy completed three passing tests involving directional turns across 120°, 180°, and 360°. Each pass was video-coded based on foot orientation (back or front foot), foot dominance (dominant or nondominant), and pass direction (toward the dominant or nondominant side). The study tested whether (i) the most common technique used varied with pass direction due to a preference for the dominant foot, (ii) performance varied across foot techniques, and (iii) scanning prior to ball reception enhanced outcomes. Results: Players preferred techniques that used their dominant foot, such as controlling and passing with their back foot (back–back) when turning to the dominant side (58% in 120° and 57% in 180° tests) and controlling with their back foot and passing with the front (back–front) for the nondominant side (66% and 55%; χ<sup>2</sup> = 292.96 and 312.87, <i>p</i> < 0.001). However, using the dominant foot sometimes led to slower, less efficient actions. In the 120° test, back–front was the fastest technique (+1.11 passes/min vs. back–back), while front–back was the slowest (−4.20 passes/min, <i>p</i> < 0.001). In the 360° test, scanning improved turn accuracy (from 51% to 73%) and performance, resulting in 4.20 more passes/min, fewer control errors (11% vs. 31%), and fewer target misses (3% vs. 10%; all <i>p</i> < 0.001). Conclusions: These findings highlight the value of effective scanning and foot technique under varied conditions, and offers coaches a practical tool for player analysis, feedback, and development.
Nonlinear variations in the coordinate time series of global navigation satellite system (GNSS) reference stations are strongly correlated with surface displacements caused by environmental loading effects, including atmospheric, hydrological, and nontidal ocean loading. Continuous improvements in the accuracy of surface mass loading products, performance of Earth models, and precise data-processing technologies have significantly advanced research on the effects of environmental loading on nonlinear variations in GNSS coordinate time series. However, owing to theoretical limitations, the lack of high spatiotemporal resolution surface mass observations, and the coupling of GNSS technology-related systematic errors, environmental loading and nonlinear GNSS reference station displacements remain inconsistent. The applicability and capability of these loading products across different regions also require further evaluation. This paper outlines methods for modeling environmental loading, surface mass loading products, and service organizations. In addition, it summarizes recent advances in applying environmental loading to address nonlinear variations in global and regional GNSS coordinate time series. Moreover, the scientific questions of existing studies are summarized, and insights into future research directions are provided. The complex nonlinear motion of reference stations is a major factor limiting the accuracy of the current terrestrial reference frame. Further refining the environmental load modeling method, establishing a surface mass distribution model with high spatiotemporal resolution and reliability, exploring other environmental load factors such as ice sheet and artificial mass-change effects, and developing an optimal data-processing model and strategy for reprocessing global reference station data consistently could contribute to the development of a millimeter-level nonlinear motion model for GNSS reference stations with actual physical significance and provide theoretical support for establishing a terrestrial reference frame with 1 mm accuracy by 2050.
Radiation safety is one of the key aspects of health protection and environmental safety in Ukraine, particularly given the developed nuclear energy sector and the consequences of past incidents, such as the Chornobyl disaster. The primary sources of radiation contamination include both natural and anthropogenic factors, such as uranium mining and processing, operation of nuclear power plants, use of radioactive materials in industry and medicine, as well as accumulation of radioactive waste at facilities like the Prydniprovskiy Chemical Plant (PCP). This paper highlights legislative, technological, and preventive measures aimed at ensuring radiation safety, and analyzes the current state of radiation contamination and risks associated with waste at PCP, which is one of the major sources of radioactive contamination in the region. The purpose of this study is to conduct a comprehensive analysis of the current state of radiation safety in Ukraine, identify the main sources of radiation contamination, and evaluate the effectiveness of measures to mitigate the impact of radiation on public health and the environment. Special attention is paid to legislative aspects, technological solutions, improvement of monitoring systems, and interaction with international organizations, such as the IAEA, to ensure compliance with the highest radiation safety standards. Conclusion. 1. It is important to improve the radiation risk management system, particularly through enhanced state control, modernization of monitoring technologies, and the implementation of new safety standards. 2. Significant attention should be paid to facilities with radioactive waste, such as PCP, where systematic reclamation measures are needed to mitigate the impact on the environment and public health. 3. The implementation of modern monitoring technologies, such as automated radiation level control systems, is essential for rapid response to elevated radiation levels. 4. International cooperation with organizations like the IAEA should be continued to introduce best practices in radiation safety, thereby enhancing the safety of nuclear power plants and ensuring the sustainable development of the country. 5. The research findings confirm the need for a comprehensive approach to reducing radiation risks, which includes both technical and social measures aimed at improving working conditions, preserving worker health, and protecting the environment from the negative effects of radiation.
Radulović Luka, Živković Saša, Antonović Saša
et al.
In this paper, an optimization method for a rocket-refurbishing project is presented. While considering the technical solution the level of reconstruction needs to be decided, from which refurbishment costs are dependent, as well as eventual increase of rocket performances. The idea of rocket motor refurbishment is to extend the life cycle and eventually increase performances for a minimum of an investment. The design shown in this paper is supposed to be an economic solution for the M63 "PLAMEN" 128 mm caliber artillery rocket, resulting in the increase in performance, without significant changes to the construction.
This paper proposes a functional carriage design and an evaluation index system to improve the operational efficiency of high-speed medical trains. Hierarchical task analysis and human-machine-environment analysis were applied to model the transfer task and the functional modules of the medical train. The functional module configuration was obtained by performing a correlation analysis between the task and function. The relationship between carriages was elucidated by analysing material, personnel and information flow, and an optimal grouping diagram was obtained. Based on this design method, an innovative 6-carriage grouping design scheme was proposed. A functional evaluation index system for the carriage design was constructed, and the 6-carriage design was compared with the conventional 8-carriage design to verify the usability of the design method. The results showed that the 6-carriage high-speed trains can be flexibly configured to suit the changing task environment and are generally better than the 8-carriage design. This study provides theoretical and methodological support for constructing efficient and rational functional carriages for high-speed medical trains.
The article presents the results of analysis of long-term dynamics of damage of protective coatings of distribution gas pipelines revealed in the process of operation. The applied methodology of complex instrumental inspection and diagnostics of insulation is highlighted. The estimation of the general level of damageability of protective coverings on the basis of the value of specific density of defects was carried out. The received results testify to an insignificant degree of wear and absence of signs of approaching the limit state of gas pipelines' insulating coatings, including those being in operation for more than 40 years. This is an additional argument in favor of revising the normative service life of steel distribution gas pipelines towards increase.
Problem statement. The work was carried out on the identification and distribution by groups of various types of emergency situations that are possible in laboratories when performing procedures with various biological agents. The need to observe clearly regulated rules for safe work with various biological objects in laboratory institutions is proved. The purpose of the article. Determine the rules for safe work with various biological agents in laboratory conditions of different security levels. Method. Analytical methods, generalizing approaches to information presented in regulatory documents, literary and other information sources. Results. Existing and previously developed rules for safe work and techniques for appropriate laboratory work with biological objects are studied. The main signs of work risks according to the international classification of microorganisms are investigated. The characteristics of each hazard group are studied and examples of microbial species assigned to a particular risk group are given. The classification characteristics for four types of microbiological laboratories according to a number of features are given. It was established that the level of laboratories’ biological safety depends on the risk group of microorganisms. It is recognized that compliance with the rules of safe work with various biological agents in laboratory conditions is ensured by the use of necessary and mandatory equipment for a certain level of the laboratory. It is argued that the possibility of implementing biological safety rules in laboratories of different levels is based on the assessment of biological risks in certain conditions of a given laboratory institution. A step-by-step procedure for assessing biological risks in a certain laboratory has been developed, which is also presented in the form of a block diagram. Scientific novelty. Scientific and normative information on the rules of safe work with biological agents in laboratory conditions is analyzed and summarized. A defined sequence of actions for biological risk assessment in certain laboratory settings is proposed. Practical value. The practical possibility and necessity of managing biological risks in laboratory conditions of different biological safety levels is substantiated.
El reconocimiento del monitoreo y conservación de especies coralinas, destaca la necesidad de promover herramientas que coadyuven a la generación de información acerca de la salud de los arrecifes coralinos en el ecosistema costero del Cabo de la Vela en La Guajira y de esta manera comprender los factores que provocan su degradación y hacer recomendaciones para la preservación de su biodiversidad, cabe resaltar que en esta zona costera existe un limitado conocimiento sobre las características de la comunidad coralina y del estado actual de las especies presentes. El propósito es generar un manual para favorecer el monitoreo in situ y conservación de especies coralinas en el ecosistema costero, es un estudio descriptivo, proyectivo, documental bibliográfico orientado a proporcionar respuestas o soluciones a problemas planteados en una determinada realidad de tipo práctico. Por tanto, en este proceso innovador la participación de todos los actores clave involucrados es fundamental; comunidad, universidades, investigadores. Se concluye, la conservación in situ del ecosistema costero del Cabo de la Vela en La Guajira, va a depender de la disponibilidad de información sobre la distribución de las especies coralinas, y el uso de indicadores bajo un enfoque ecorregional basado en el conocimiento científico de esta disciplina.
The non-uniform temperature distribution in large-format lithium-ion batteries (LIBs) can lead to thermal runaway or performance degradation. This study develops a three-dimensional electrochemical–thermal model of a 55-Ah large-format LiFePO4/graphite pouch cell and statistically analyzes the effects of width, height, and attachment positions of the nominal tab (NT), lateral tab (LT), and counter tab (CT) on the temperature distribution. The temperature difference that occurs across the cell is analyzed separately for each design factor through design of experiments (DOE) and analysis of variance (ANOVA). Accordingly, wider tabs reduce the maximum temperature and temperature difference irrespective of the tab type. Taller tabs yield higher maximum temperatures, resulting in a larger temperature difference. Attaching tabs to the edge of the cell increases the maximum temperature and temperature difference. The locations of the negative NTs and CTs do not affect the temperature difference. However, the location of the negative LT increases the minimum temperature, thereby decreasing the temperature difference. The ANOVA revealed that the p-value of the width, height, and attachment position of the positive tab is lower than 0.05 which means the factors strongly influence the temperature difference for all tab-types. Also, the attachment position of the negative tab affects only the LT-type.
Mustafa Okati, Mahdiyeh Eslami, Mahdi Jafari Shahbazadeh
This paper focuses on introducing a transformerless DC/DC converter with low total switching device power in dual working modes including step-up and step-up/down modes. The proposed converter is analysed in terms of the continuous conduction mode, steady state, and efficiency with the replacement of parasitic resistance effects. The proposed converter in the step-up mode has a high voltage gain ratio and a continuous input current. Then, the other working mode of the proposed converter with relevant DC/DC converters is compared. By this comparison, the proposed converter has a high voltage gain ratio. Also, the converter characteristics such as voltage stress on power switches and charge pump capacitors are in a good condition in this mode. Finally, the experimental results from a laboratory made prototype and the obtained waveforms from the simulation in PLECS are presented for validation such as higher voltage gain ratio, lower total switching device power and better efficiency.