Results Of Numerical Research Research Articles

Psychological Impact of the Northern Ethiopia War on Tigray Athletes

The war in northern Ethiopia (November 4, 2020-November 2, 2022) caused unimaginable suffering to the people of Tigray. Psychological suffering is among the many. It is well known that war affects all people living in the war zone and alters life dramatically, as its effects can be both physical injury of varying degrees of severity and the dangerous invisible wounds caused by psychological trauma and stress. As far as this issue is concerned, numerous research results have shown the psychological impact of war on the general population. However, no research has been carried out on the psychological impact of war on athletes. So, the main objective of this study was to assess the psychological impact of the Northern Ethiopia civil war on Tigray Athletes. To achieve the purpose of this study, a total of 144 athletes from various clubs in the Tigray area were selected using the convenience sampling method. The anxiety symptom was assessed using the Generalized Anxiety Disorder Scale (GAD-7) and the depression symptom was assessed using the Centre for Epidemiologic Studies (CES-D) depression scale. The data gathered was analyzed using the SPSS statistical package (version 25 for Windows). Of 144 participants, 1 (0.7%) showed minimal anxiety; 4 (2.8%) showed mild anxiety; 29 (20.1%) showed moderate anxiety; and 110 (76.4%) showed severe anxiety. And regarding depression, all of the participants were shown symptoms of depression as their score was higher than 16 points. As the result shows, almost all participants have a risk of anxiety and depression. It can thus be concluded that the two-year war in northern Ethiopia had a negative psychological impact on Tigray athletes.

A-Star (A*) with Map Processing for the Global Path Planning of Autonomous Underwater and Surface Vehicles Operating in Large Areas

The global path planning system is one of the basic systems ensuring the autonomous operation of unmanned underwater vehicles (UUVs) and unmanned surface vehicles (USVs) in a complex aquatic environment. The A* path planning algorithm is one of the most well-known algorithms used to obtain an almost optimal path, avoiding obstacles even in a complex environment containing objects with specific shapes and non-uniform arrangements. The main disadvantage of this algorithm is the computational cost of path calculation. This article presents a new approach based on the image processing of the map before determining the path using A*. The results of numerical research based on a large-sized map expressing the port area confirm the proposed method’s effectiveness, which reduces the calculation time by over 500 times with a slight increase in the path length compared to the basic version of the A* algorithm. Based on the obtained results, the proposed approach also increases the path’s safety by designating narrow and risky areas as closed to vehicle movement. For this reason, the method seems suitable for use in global path planning for autonomous underwater vehicles (AUVs) and autonomous surface vehicles (ASVs) operating in large areas.

Berberine Contents as a Quality Marker in Medicinal Plants and Amounts of Berberine Passing into Serum

Background: Berberine is an alkaloid found in some medicinal plants. Berberine-containing plants have traditionally been used in the treatment of diseases since ancient times. Berberine is a natural compound that has an important place in traditional Chinese medicine. Currently, berberine is being evaluated extensively in clinical trials and is one of the natural products on which most scientific research studies have been published. Numerous clinical and pharmacological research results have been published on the therapeutic effect of berberine against cancer, diabetes, and heart disease Objective: The first purpose of this review is to display the berberine content of plants found in different regions of the world, and the second purpose is to provide the amount of berberine passing into the serum. Methods: Herbal supplements and extracts prepared from plants containing berberine are commercially marketed. The content of berberine in plants varies widely, and berberine is a quality indicator for many medicinal plants. Results: Different analytical methods have been developed for reliable berberine analysis. Plant and serum berberine levels reported between the years 2013 and 2022 in journals covered by SCI are collected in this review article. Conclusion: We hope that this overview of berberine amounts will be useful in future pharmaceutical and pharmacokinetic studies.

Comparative study on vanadium(V) adsorption performance of supported ionic liquid synthesized by physical impregnation and chemical grafting

This study loaded ionic liquids (ILs) onto chloromethylated polystyrene resins using physical impregnation and chemical grafting. The resulting ionic liquid-loaded resins were characterized using SEM-EDS, FTIR, and NMR spectral analyses, confirming the successful preparation of both the physical impregnation resin (PIR) and the chemical grafting resin (CGR). The study compared the influencing conditions, cyclicity, selectivity, and adsorption mechanism of PIR and CGR on adsorption vanadium(V). Under optimum adsorption conditions, CGR exhibited significantly higher adsorption capacity (261 mg/g) than PIR (27 mg/g). In terms of adsorption selectivity, the separation coefficients of CGR for Fe and Al (65.3 and 45.4) were much larger than those of PIR (6.3 and 10.6). Furthermore, the CGR exhibited a cycling capacity 1.5 times greater than the PIR, maintaining an adsorption capacity of over 98 % of the initial value within 12 cycles. Based on the adsorption mechanism, both loaded resins conform to the monolayer chemisorption described by Langmuir isothermal adsorption model and the pseudo-second-order kinetic model. The results showed that the adsorption performance, selectivity, and adsorption stability of CGR were considerably superior to those of PIR. A further comparison with numerous previous research results revealed that the adsorption capacity of CGR for vanadium was significantly increased, and the cycling performance was substantially enhanced, while the separation between it and the impurity ions was also improved.

Effect of burner structural parameters on combustion characteristics and NOx emission of natural gas

The low-nitrogen combustion of natural gas has always been a crucial topic in environmental protection. Currently, small and medium-sized industries use straight-through pipelines as their burner nozzles. This design results in poor heat diffusion capacity after mixed combustion and a long time of temperature diffusion, leading to low combustion efficiency and high NOx emissions. To address this issue, a new type of natural gas low-nitrogen burner with a multi-port diffusion nozzle was developed. The burner’s structure was optimized through a combined approach of experiment and numerical simulation. The optimal structural parameters for the burner are a 40° swirl angle and 8 swirl blades, as indicated by the numerical simulation research results. The designed multi-port diffusion nozzle is matched with the appropriate swirl angle and number of blades to promote natural gas diffusion, forming an annular space region flames and a stable flame shape with a height of 0.64 m. After optimization, the average concentration of NOx at the outlet of the combustion chamber decreased from 61.5 ppm to 20.81 ppm. A natural gas low-nitrogen combustion experimental system was designed and constructed based on simulation results. The experimental results were analyzed in terms of flame structure characteristics, temperature distribution, and NOx emissions. The results indicate that the trend in temperature change is consistent with the simulation process. The NOx concentration at the outlet of the combustion chamber was measured by the flue gas analyzer to be 34.1 ppm, which was 5.3 ppm lower than the NOx concentration calculated by numerical simulation. The new burner exhibited better flame stability and a 12.6 % reduction in NOx emissions compared with a traditional straight-through pipeline burner of the same size. The designed natural gas low-nitrogen burner appears to be a suitable device for reducing NOx emissions in small and medium-sized industries.

Enhancing interpretability in data-driven modeling of photovoltaic inverter systems through digital twin approach

The utilization of data-driven modeling techniques has been extensively employed in the simulation analysis, power prediction, and condition monitoring of photovoltaic power generation systems. However, the absence of interpretability regarding the intrinsic mechanisms in the modeling process has resulted in numerous constraints in practical implementation and subsequent promotion. To this end, we propose a novel digital twin modeling approach that eliminates the need for injecting additional signals or sensors, estimating unknown parameters in the mechanism model solely by using operational data from physical systems. A time synchronization filter was added to address the frequency mismatch between the actual sampling frequency and the solution step size. The results of numerical research indicate that the proposed digital twin model has the ability to accurately simulate the dynamic characteristics of photovoltaic grid connected inverters. The digital twin model of photovoltaic inverters has achieved good results in the cross experiment of device degradation trend monitoring, indicating that the proposed method is expected to make significant contributions to the simulation, power prediction, and degradation monitoring of grid connected photovoltaic systems.

GP-HTNLoc: A graph prototype head-tail network-based model for multi-label subcellular localization prediction of ncRNAs

Numerous research results demonstrated that understanding the subcellular localization of non-coding RNAs (ncRNAs) is pivotal in elucidating their roles and regulatory mechanisms in cells. Despite the existence of over ten computational models dedicated to predicting the subcellular localization of ncRNAs, a majority of these models are designed solely for single-label prediction. In reality, ncRNAs often exhibit localization across multiple subcellular compartments. Furthermore, the existing multi-label localization prediction models are insufficient in addressing the challenges posed by the scarcity of training samples and class imbalance in ncRNA dataset. To address these limitations, this study proposes a novel multi-label localization prediction model for ncRNAs, named GP-HTNLoc. To mitigate class imbalance, GP-HTNLoc adopts separate training approaches for head and tail location labels. Additionally, GP-HTNLoc introduces a pioneering graph prototype module to enhance its performance in small-sample, multi-label scenarios. The experimental results based on 10-fold cross-validation on benchmark datasets demonstrate that GP-HTNLoc achieves competitive predictive performance. The average results from 10 rounds of testing on an independent dataset show that GP-HTNLoc outperforms the best existing models on the human lncRNA, human snoRNA, and human miRNA subsets, with average precision improvements of 31.5%, 14.2%, and 5.6%, respectively, reaching 0.685, 0.632, and 0.704. A user-friendly online GP-HTNLoc server is accessible at https://56s8y85390.goho.co.

Метод чисельного визначення динамічних характеристик лопаті повітряного гвинта з композиційного матеріалу

The subject matter of this article is the dynamic characteristics of a composite propeller blade. Determination of the modes and frequencies of natural vibrations is necessary to predict the dangerous resonance modes of aircraft engines and to identify the most stressed local zones of the blade surface. The goal of this study is to develop a verified method for determining the dynamic characteristics of composite rotor parts of aircraft engines based on the known properties of the structural components of the composite material. A general mathematical statement of the problem of elasticity theory for the analysis of the dynamic characteristics of composite structures is described. A complete system of equations that describes the mechanical state of the body within the framework of the continuum mechanics approach was developed. Geometric modeling of the propeller blades was performed. Modeling and numerical investigation of the natural frequencies and mode shapes of the propeller blade were performed using the finite element method using the ANSYS software package. Based on the results of numerical research of the stressed and deformed state of the propeller blade, the first five natural vibration frequencies and the distribution of the local stress field were determined. The most stressed local zones on the blade surface were determined for each form of natural vibration. The propeller blade model was verified using an experimental study of the first five forms and frequencies of natural blade vibrations. The eigenfrequencies of the blade vibration were experimentally determined using the method of free (natural) vibrations. The resonance method was used to experimentally determine the resonant frequencies and vibration modes of the blade. The distribution of the blade deformation field was investigated using the strain gauge method. The highest error in the verification of numerical and experimental research is 4.11% for the fourth vibration frequency. Conclusions. The scientific novelty of the results obtained is that the effective elastic properties of the composite material for calculations should be determined using the procedure of numerical homogenisation of composite materials of different reinforcement structures by the properties of the matrix and fibers. The method does not require experimental determination of the effective elastic constants for the layers of blade components of different weave architecture patterns.

Performance Analysis of Deep Learning-Based Detection/Classification for SAR Ground Targets with the Synthetic Dataset

Based on the recently developed deep learning technology, many studies have been conducted on deep learning networks that simultaneously detect and classify targets of interest in synthetic aperture radar(SAR) images. Although numerous research results have been derived mainly with the open SAR ship datasets, there is a lack of work carried out on the deep learning network aimed at detecting and classifying SAR ground targets and trained with the synthetic dataset generated from electromagnetic scattering simulations. In this respect, this paper presents the deep learning network trained with the synthetic dataset and applies it to detecting and classifying real SAR ground targets. With experiment results, this paper also analyzes the network performance according to the composition ratio between the real measured data and the synthetic data involved in network training. Finally, the summary and limitations are discussed to give information on the future research direction.

Role, residues and microbial degradation of plant growth regulators (PGRs): A scoping review

Plant growth regulators (PGRs) play an important role in increasing crop yield, and quality, and enhancing crop stress resistance in agricultural production, especially for important crops. PGRs can affect the transport and distribution of assimilates by changing the content and distribution of endogenous hormones in plants. Numerous empirical research results have proven that PGRs have an important impact on the growth, development, and yield composition of wheat. Taking wheat plants as an example, this study reviews the application of PGRs in wheat production and explores their impact on wheat growth and yield. Furthermore, residues and microbial degradation of PGRs are summarized in detail. Finally, future research directions on PGR application in wheat production are proposed. This summary is of great significance for understanding the role of PGRs in wheat production.

A review on hazards and risks to pipeline operation under transporting hydrogen energy and hydrogen-mixed natural gas

As an efficient and clean fuel, hydrogen energy plays an important role in relieving the energy crisis and achieving the orientation of zero carbon emissions. Transportation is the key link in the construction of hydrogen energy infrastructure. For large-scale and long-distance transportation of hydrogen, pipeline transportation has the advantages of high efficiency and cost saving. While using the existing natural gas pipeline to transport hydrogen, it would economize the economic cost, time cost and labor cost. However, the transportation of hydrogen may bring more hazards and risks. Based on the investigation of a large number of literatures, the research advance in hydrogen embrittlement, leakage, combustion and explosion risk of hydrogen and hydrogen-mixed natural gas pipelines was reviewed. The mechanism, research means and evaluation methods of hydrogen embrittlement, as well as the experimental and numerical simulation research results of leakage, combustion and explosion were discussed in detail. The definite and important conclusions include: (1) For buried hydrogen-mixed natural gas transportation pipeline, the leakage rate of hydrogen and methane is the same, the formation of the leakage crater is foreign to the nature of leakage gas. (2) When adding less than 25 volume percentage of hydrogen into the natural gas pipelines, the explosion risk would not be increased. Future research should focus on the risk prediction, quantitative risk assessment, intelligent monitoring, and explosion-suppression technical measures of hydrogen and hydrogen-mixed natural gas transportation pipelines, so as to establish comprehensive and multi-level pipeline safety protection barriers.

Kritički osvrt na vezove sa spriječenim izvijanjem dijagonala

Currently, buckling restrained braces are gaining popularity in earthquake resistant designs. These braces facilitate stable hysteretic behaviour with a non-buckling steel core encased in a steel tube, which is filled with concrete or mortar. However, in the last few years, researchers have observed that there is no need for the filler material and these braces can be made of steel. This paper presents a summary of buckling restrained braces on the grounds of numerical and experimental research results and attempts to summarize the basic design provisions according to the American standards and recommendations from the available research. The paper also discusses the concept, stability criteria, initial and post stiffness, energy dissipation capacity, failure modes observed, and the practical applications of buckling restrained braces, followed by conclusions and future suggestions for the development of these braces.

Experimental and Analytical Studies of String Steel Structure for Bridges

Due to their efficiency, suspension structures are widely used in both roof slabs and different kinds of bridges, from which stress ribbon pedestrian bridges can be distinguished. The main disadvantage of the latter is high deformability, especially under asymmetrical loads. Recently, string structures or their systems have been introduced into bridge building. Numerical and experimental analysis of string behaviour under symmetrical and asymmetrical loads is carried out in the article. Analytical expressions for the calculation of string displacements and tensile forces are presented. The impact of the string pre-stress on the state of its stresses and deformations was evaluated. The assessment of the accuracy of analytical expressions by applying the results of numerical and experimental research is presented. A methodology is proposed for calculating the pre-stressing force taking into account the operational requirements. Three main loading options at different string pre-stress values are analysed. It is worth mentioning that the difference (error) between the analytical and numerical results is not extensive, it does not exceed 3%. It is necessary to notice that in all cases, the analytically obtained results are somewhat higher than FEM (numerically) obtained results.

Experimental and Analytical Studies of String Steel Structure for Bridges

Due to their efficiency, suspension structures are widely used in both roof slabs and different kinds of bridges, from which stress ribbon pedestrian bridges can be distinguished. The main disadvantage of the latter is high deformability, especially under asymmetrical loads. Recently, string structures or their systems have been introduced into bridge building. Numerical and experimental analysis of string behaviour under symmetrical and asymmetrical loads is carried out in the article. Analytical expressions for the calculation of string displacements and tensile forces are presented. The impact of the string pre-stress on the state of its stresses and deformations was evaluated. The assessment of the accuracy of analytical expressions by applying the results of numerical and experimental research is presented. A methodology is proposed for calculating the pre-stressing force taking into account the operational requirements. Three main loading options at different string pre-stress values are analysed. It is worth mentioning that the difference (error) between the analytical and numerical results is not extensive, it does not exceed 3%. It is necessary to notice that in all cases, the analytically obtained results are somewhat higher than FEM (numerically) obtained results.

From heart failure and kidney dysfunction to cardiorenal syndrome: TMAO may be a bridge

The study of trimethylamine oxide (TMAO), a metabolite of gut microbiota, and heart failure and chronic kidney disease has made preliminary achievements and been summarized by many researchers, but its research in the field of cardiorenal syndrome is just beginning. TMAO is derived from the trimethylamine (TMA) that is produced by the gut microbiota after consumption of carnitine and choline and is then transformed by flavin-containing monooxygenase (FMO) in the liver. Numerous research results have shown that TMAO not only participates in the pathophysiological progression of heart and renal diseases but also significantly affects outcomes in chronic heart failure (CHF) and chronic kidney disease (CKD), besides influencing the general health of populations. Elevated circulating TMAO levels are associated with adverse cardiovascular events such as HF, myocardial infarction, and stroke, patients with CKD have a poor prognosis as well. However, no study has confirmed an association between TMAO and cardiorenal syndrome (CRS). As a syndrome in which heart and kidney diseases intersect, CRS is often overlooked by clinicians. Here, we summarize the research on TMAO in HF and kidney disease and review the existing biomarkers of CRS. At the same time, we introduced the relationship between exercise and gut microbiota, and appropriately explored the possible mechanisms by which exercise affects gut microbiota. Finally, we discuss whether TMAO can serve as a biomarker of CRS, with the aim of providing new strategies for the detection, prognostic, and treatment evaluation of CRS.

Theoretical analysis and experimental tests of tilting pad journal bearings with shoes made of polymer material and low-boiling liquid lubrication

Selecting the appropriate bearing system for the rotor requires a good knowledge of the available solutions and the operating conditions of the machine. For newly designed machinery operating in adverse conditions, selecting bearings that ensure correct and long-lasting operation can be extremely challenging. Difficulties increase when the machine's operating parameters are beyond the technical capabilities of available technical solutions. This article presents the course of the design process and results of numerical and experimental research of a prototype microturbine that uses an innovative rotor-bearing system. Due to the adverse operating conditions, new tilting pad journal bearings were designed, in which the sliding surfaces of the tilting pads were made of polymeric material and a low-viscosity medium in liquid form was used as the lubricating medium. The basic bearing parameters were selected and pre-checked by numerical calculations. The oil-free turbomachinery design thus developed was subjected to experimental testing under near-real conditions. The results of these tests confirmed that the developed bearings performed very well, ensuring stable operation of the high-speed rotor of the microturbine over a wide speed range. Despite the unfavourable lubrication conditions, no signs of bearing wear were observed. The results obtained indicate a new, promising direction for the development of bearing systems for turbomachinery, in which, with a suitable design of the bearings, a low-boiling working medium in liquid form can be used as a lubricating medium.

Podążanie za zadaną trajektorią grupy robotów kołowych z użyciem wirtualnych połączeń sprężysto-tłumiących

The article presents the solution to the problem of trajectory tracking of a self-organized group of wheeled robots in the environment without obstacles. The group of robots is tracking a trajectory realized as following a reference point by the geometric center of the group, as well as simultaneously, reaching and maintaining a given distance between neighboring robots. The proposed method is based on virtual forces from virtual spring-damper connections between robots, which allows for the trajectory tracking of the previously self-organized group while maintaining its desired shape. The presented method of control is described in detail with the description of i-th robot dynamics and was tested numerically and experimentally. The paper presents the results of numerical tests and experimental research and ends with discussion and conclusions. The paper’s results could be expanded for applications related to robotic group trajectory tracking.

Research of Multi-Mode Pneumatic Vibroactuator

A multi-functional, three-mode, self-exciting pneumatic vibroactuator was investigated. The special feature of this vibroactuator is that it consists of two excitation chambers connected by an elastic synchronizing chain. A mathematical model of the vibroactuator was created, which was solved by numerical methods. The laws (modes) of the movement of the working organ of this vibroactuator have been determined: harmonic, non-harmonic, and pulsating. The results of numerical and experimental research are compared. The vibroactuator with these extended functional capabilities can be used for the intensification of various production technological processes.

The Negative Impact of Social Media on Youth’s Social Lives

The results of numerous scientific researches in developed countries shows that the content produced by social media has a significant impact on the behavior and lifestyle of young people, especially in developing countries such as Afghanistan; But the main problem is that there has been no serious awareness and cognition about the harmful impact of social media content on young people on developing countries, which is comprehensively discussed in this research paper. The general purpose of this paper is to provide information and create awareness about the negative impact of social media on youth's social behavior through content analyses and qualitative research. Social Media refers to different types of platforms or applications such as WhatsApp, Facebook, TikTok, Twitter, LinkedIn, YouTube, etc. through which people share information and use it as a communication resource.This study has specifically addressed the basic questions that How social media changes youth's social behavior and what are the main factors which because social behavior changes in youths by using social media and what are the negative impact of social media on youth's social lives by using reliable resources. Even though social media sites and platforms have more advantages and positive impacts and provide a lot of communication, business, and entertainment opportunities, it leads to social isolation, anxiety, depression, cyberbullying, sexuality, loss of privacy, terrorism, etc. It reduces the number of face-to-face interactions among the youth because they normally spend most of their time on online social platforms. The result of this research shows that social media leads to social isolation and this can cause several effects such as physical, emotional, mental, and psychological issues on youths. This can lead to depression, anxiety, and many other problems.

Toughening of Ni-Mn-Based Polycrystalline Ferromagnetic Shape Memory Alloys.

Solid-state refrigeration technology is expected to replace conventional gas compression refrigeration technology because it is environmentally friendly and highly efficient. Among various solid-state magnetocaloric materials, Ni-Mn-based ferromagnetic shape memory alloys (SMAs) have attracted widespread attention due to their multifunctional properties, such as their magnetocaloric effect, elastocaloric effect, barocaloric effect, magnetoresistance, magnetic field-induced strain, etc. Recently, a series of in-depth studies on the thermal effects of Ni-Mn-based magnetic SMAs have been carried out, and numerous research results have been obtained. It has been found that poor toughness and cyclic stability greatly limit the practical application of magnetic SMAs in solid-state refrigeration. In this review, the influences of element doping, microstructure design, and the size effect on the strength and toughness of Ni-Mn-based ferromagnetic SMAs and their underlying mechanisms are systematically summarized. The pros and cons of different methods in enhancing the toughness of Ni-Mn-based SMAs are compared, and the unresolved issues are analyzed. The main research directions of Ni-Mn-based ferromagnetic SMAs are proposed and discussed, which are of scientific and technological significance and could promote the application of Ni-Mn-based ferromagnetic SMAs in various fields.