Main Characteristics Research Articles

Structure and Validation of a Kinematic Surface Simulation Model for the Direct Laser Writing Process

The article introduces the structure and validation of a kinematic surface simulation model for the replication of laser‐structured surfaces and their impressions after hot embossing. The surface replication is accomplished by the stepwise Boolean intersection of a structured and digitized point ablation with the workpiece. The resulting surface is characterized according to ISO 25178. Resulting from the kinematic simulation principle, the model can be applied to a wide range of material–machine combinations in the field of laser structuring and enables a time–efficient, nanometer‐resolved replication of representative surfaces with a size up to several square millimeters. Within the validation process it was proven that the main surface characteristics can be predicted by the model. Compared to AI approaches and numerical or multiphysical simulations, preliminary studies are only needed to a very small extent. Furthermore, complex influences such as material and temperature‐related properties do not need separate consideration as they are taken into account by the digitized point ablation.

Ploidy and fruit trait variation of oil-tea Camellia: Implication for ploidy breeding1

Plant polyploidy often occurs along with higher yield and superior quality. Therefore, obtaining polyploid germplasms is a significant part of breeding. The oil-tea Camellia tree, an important native woody plant that produces high-quality edible oil, includes many species of Camellia with different ploidies. However, whether higher ploidy levels in oil-tea Camellia trees are related to better traits remains unclear. In this study, the ploidy levels of 30 different oil-tea Camellia strains in 3 different species in the sect. Paracamellia were determined by flow cytometry and chromosome preparation, and the phenotypic characteristics and fatty acid composition of the fruits were examined by field observations and laboratory analyses. The correlations between the ploidy level of oil-tea Camellia and the main traits of the fruit were investigated . Our results showed that 10 Camellia lanceoleosa strains were diploid, 10 Camellia meiocarpa strains were tetraploid and 10 Camellia oleifera strains were hexaploid. Hexaploid C. oleifera had larger fruit size and weight, more seeds per fruit, larger seed weight per fruit, higher oil contents and larger yield per crown width than tetraploid C. meiocarpa and diploid C. lanceoleosa, but their fruit peel thickness and fresh seed rate were significantly lower, and these traits were significantly correlated with ploidy. In addition, in terms of fatty acid composition, hexaploid C. oleifera had a higher oleic acid content than tetraploid C. meiocarpa and diploid C. lanceoleosa, but their linoleic acid, linolenic acid and arachidonic acid contents were lower. The contents of palmitic acid, stearic acid and total unsaturated fatty acids were not significantly correlated with ploidy level. In conclusion, there were certain correlations between the main characteristics of oil-tea Camellia fruit and the ploidy level, and increasing ploidy level led to an increase in fruit yield, with no effect on oil composition. The discovery of the variation in the main characteristics of oil-tea Camellia fruit with different ploidies will facilitate germplasm innovation and lay a foundation for ploidy breeding and mechanistic research on fruit traits.

Экспериментальное исследование гидравлических характеристик сферических насадок для массообменных аппаратов

A critical analysis of the trends in the development of nozzles for mass transfer devices is given, some designs are described in which the transfer of heat and mass is organized from the standpoint of today technically the most perfect. It is shown that the specific surface, the free specific volume of the nozzle and the hydraulic resistance of the layer are determined as the main characteristics of irregular type packing bodies. The scheme and description of an experimental setup for determining the hydrodynamic characteristics of nozzles in laboratory conditions are given. The results of studies of the hydrodynamic parameters of a layer consisting of a spherical hollow irregular nozzle for a dry and irrigated column are presented. The singular velocities of the gas flow corresponding to the transition points (points of deceleration, suspension, inversion or choking) to different hydrodynamic modes of operation of the filling mass transfer columns (film, intermediate, turbulent) and corresponding pressure drops have been experimentally determined. The dependences of the hydraulic resistance of the nozzle layer on the gas velocity in the column for dry and irrigated nozzles with a 1 m high layer are determined. The main reasons for the decrease in gas pressure in the layer of the irrigated nozzle are indicated. The singular gas flow velocities and their corresponding pressure drops are calculated using known empirical dependencies for dry and irrigated nozzles. The results of experimental studies and engineering calculations were compared, thereby proving the possibility of using computational equations with satisfactory accuracy (up to 15%). The study of the hydrodynamics of the layer and its hydraulic characteristics has shown that the spherical, hollow nozzle design with evenly spaced holes on the surface provides an effective redistribution of working phases in the mass transfer apparatus.

ANALYSIS AND MODERNIZATION OF GAS PRODUCTION SYSTEMS FROM COMPRESSOR STATION EQUIPMENT

Reducing methane emissions into the atmosphere to minimize negative impacts on the environment and climate are the main objectives of the environmental policies of PJSC Gazprom and the Russian Federation as a whole. According to experts’ estimates, the Earth is facing a crisis situation due to greenhouse gas emissions into the atmosphere. In this study, an analysis of the most effective existing technologies for gas recovery from compressor station equipment was conducted, and based on their advantages and disadvantages, a new system called the Mobile Ejector Unit (MEU) was proposed. The MEU is based on a two-stage jet ejector, whose main characteristics were obtained through calculations using G.N. Abramovich’s methodology. Along with the new system, modification schemes for the valve unit to connect the MEU, gas recovery scheme from the centrifugal booster circuit, and the compressor workshop circuit are proposed. The calculation of evacuation time depending on the used recovery scheme was carried out, and an economic evaluation of the efficiency of implementing the mobile ejector unit was provided. As a result, it can be concluded that the presented technology is efficient and versatile due to its simplicity in operation, cost-effectiveness, and mobility.

Identifying the influence of design parameters of single-chamber hydrostatic bearing of fuel pump on its main characteristics

The object of this study is hydrostatic processes in the fluid friction bearings of gear-type aviation fuel pumps. The problem of the influence of the design parameters of a single-chamber hydrostatic bearing on its main characteristics was solved. The main characteristics were considered to be the load-bearing capacity and the flow rate of the working fluid. When determining the main characteristics of a single-chamber hydrostatic bearing, the Reynolds and flow balance equations were solved jointly. The resulting diagram of pressure distribution over the working surface of the bearing was used to determine the main characteristics. The influence of the clearance, nozzle diameter, and chamber width on the load-bearing capacity and working fluid flow of a single-chamber hydrostatic bearing was studied. It has been established that as the gap increases, the load-bearing capacity of a single-chamber bearing decreases, and the flow rate of the working fluid increases. As the nozzle diameter increases, the bearing's load-bearing capacity increases. Increasing the width of the chambers leads to an increase in the load-bearing capacity and flow of working fluid through the bearing. When the gap increases from 0.0125 mm to 0.0425 mm, the bearing capacity decreases by 1.156 times. The flow rate of working fluid through the bearing increases by 1.4 times. With an increase in the nozzle diameter from 1.5 mm to 3 mm, the bearing capacity increases slightly by approximately 1.02 times. Increasing the width of the chambers from 4 mm to 8 mm increases the load-bearing capacity by 1.29 times and increases the flow rate of working fluid by 1.4 times. The results show that a single-chamber hydrostatic bearing can provide the required load-bearing capacity by selecting design parameters. The given mathematical dependences could be used for practical calculations of single-chamber hydrostatic bearings

Investigation of Queuing Systems in System Structure Management

Queuing theory is used to develop recommendations for constructing queuing systems efficiently, organizing the associated operations and functionalities, and regulating request flows for optimal performance. This paper presents a study of the income functional for two specific cases of controlled queuing systems: the M/G*/1/N* system for a controlled service duration and number of waiting spaces, and the G*/M/n/m queuing system with a controlled arrival flow. The construction of a controlled semi-Markov process and the construction of an income functional on its trajectories were used as the basis for this study. The task is to find the optimal control strategy in the given queuing systems. An algorithm for finding optimal strategies applicable to similar queuing systems to increase their functioning efficiency when controlling the system’s main characteristics was developed for both systems.

THE INFLUENCE OF TRANSCRANIAL DIRECT CURRENT STIMULATION ON FUNCTIONAL RECOVERY AFTER STROKE: A SYSTEMATIC REVIEW

INTRODUCTION: Stroke is the third leading cause of death in the world and second in Brazil, whose main characteristics are global or focal disorders of brain functions, involving cognitive and mainly physical limitations, including motor, sensory changes, ataxias, apraxias and aphasias. Transcranial Direct Current Stimulation (ETCC) is a non-pharmacological treatment that has demonstrated relevant benefits in the rehabilitation of patients. OBJECTIVE: to verify the effects of ETCC on the functional capacity of post-stroke patients, focusing on efficacy and results in the face of individuals' motor disorders. METHOD: The searches were performed in the databases PeDRO, Cochrane, PubMed and MEDLINE. Eligible studies included at least one of the population outcomes ≥ 18 years, resulting from the intervention, therapeutic efficacy and Motor activity. RESULTS:Seven were selected according to the inclusion and exclusion criteria, published between 2015 and 2020. CONCLUSION: ETCC, applied in isolation, can be an effective technique to improve motor deficits after stroke, including injured upper limb function, lower limb strength, unilateral neglect, mobility and Daily Living Activities. It is suggested to carry out further studies for the standardization of a treatment protocol, as well as to verify the best moment of its application in the post-stroke patient.

Exploring an Effective International Higher Education Partnership Model Through Virtual Student Mobility Programs: A Case Study

Purpose This study examined the role of virtual student mobility (VSM) programs in developing international education partnerships and explored key factors for building successful transnational partnerships. Design/Approach/Methods Drawing on Yin’s case study approach, we explored several VSM programs offered by a Japanese national university in partnership with four research universities in China. Data sources included an autoethnographic account of planning and organizing virtual exchange programs and interviews with the partner universities’ virtual exchange program coordinators as well as with students who took different virtual exchange courses under the partnership. Findings Our case study showed that VSM models require significant collaboration, support, and commitment from universities to offer high-quality exchange programs. The initial establishment of VSM programs relies on existing relationships, clear communication, and a commitment to collaborate; however, VSM programs’ success depends heavily on the quality of online support, as well as inter-university communication and collaboration between administrators and faculty and intra-university communication and collaboration with partner universities. Based on the research results and the previous literature on international higher education partnerships, we propose a renewed partnership model in VSM comprising three main characteristics: (1) effective coordination and support, (2) effective communication, and (3) a commitment to partnership. Originality/Value Amidst emerging VSM models in higher education, this study contributes to the literature by proposing a renewed partnership model for sustaining VSM programs.

Challenges and prospects in energetic application of Pithecellobium dulce (Roxb.) Benth as a bioenergy tree

AbstractA report on the Pithecellobium dulce tree is provided in this review. The main characteristics of the tree, its chemical composition, traditional applications and future application in the bioenergy area are addressed. Pithecellobium dulce is a leguminous tree characterized by being fast growing, nitrogen fixing and largely available. In addition, it is distinguished by growing in different types of soils from acid to alkaline and with little water. This review could serve as a scientific basis to promote and carry out new research work focused on individual and comprehensive use for various bioenergetic processes, from the different parts that make up the P. dulce tree such as its leaves, pods, branches, flowers, fruit and seeds. Among the bioenergetic processes that could be developed are the production of bioethanol, biodiesel, biogas, heterogeneous catalysts, biochar, activated carbon and nanoparticles, among other applications.

Influence of Polymer Fibers on the Structure and Properties of Modified Variatropic Vibrocentrifuged Concrete.

The application of polymer materials in concrete structures is widespread and effectively used. However, there is a lack of a systematic knowledge base about the structure formation and properties of variatropic vibrocentrifuged modified fiber-reinforced concrete. The purpose of this work is the investigation of the influence of polypropylene (PF) and basalt fiber (BF) and modification with microsilica (MS) on the properties of variatropic concretes obtained using the synthesized vibration centrifugation technology. Test samples were made using vibration centrifugation technology, followed by sawing. Various types of fiber reinforcement were studied, both individually and in combination. To determine the degree of effectiveness of each recipe solution, the following main characteristics were monitored: the density and workability of concrete mixtures; the density of hardened composites; compressive strength (CS); bending strength (BS); water absorption (WA). In variatropic vibrocentrifuged concrete, the greatest efficiency is achieved with dispersed BF reinforcement in an amount of 1.5%. Compared to the control composition, the increase in CS was 8.50%, the increase in BS was 79.17%, and WA decreased by 27.54%. With PF reinforcement, the greatest effect was recorded at a dosage of 1.0%. The increase in CS was 3.16%, the increase in BS was 10.42%, and WA decreased by 17.39%. The MS modification showed the best effect with 8% replacement of part of the Portland cement. The increase in CS was 17.43%, the increase in BS was 14.58%, and WA decreased by 33.30%. The most effective and economically rational formulation solution for vibrocentrifuged concrete is combined fiber reinforcement in combination with the MS modification in the following quantities: BF-1.0%; PF-0.5%; MS-8%. The increase in CS was 22.82%, the increase in BS was 85.42%, and WA decreased by 37.68%.

National project «Education» of the Russian Federation in the conditions of the modern world

The national project in the field of education at the present moment of time is being developed together with the projects aimed at the development of the health care system, housing construction and agriculture. Modern national projects are a tool that aims to achieve the most important goals of state development. The main purpose of writing this paper is to determine the main characteristics of the national project «Education» on the territory of the Russian Federation. The methodological basis of the study is analysis and synthesis, economic< statistical and graphical methods. The result of the study reflects the essence of the national project «Education» in the Russian Federation, defines its key areas and targets, expected results from the implementation. The education system is a unique social institution designed to improve human potential, create new ideas, goals, solve various levels of complexity of tasks — these positions form both the social future and the future of each individual and citizen. In the modern world every person should have humanity, justice, morality, kindness and courtesy, it is the education system that will help to realize and develop these functions.The National Project «Education» helps to form uniform conditions for education among all territorial subjects of the Russian Federation, helps to introduce new management mechanisms.The paper also analyzes the main results of the Ministry of Education and Science of the Russian Federation in the implementation of the national project, identifies problems and offers recommendations for their solution.

The Discussion of Communicative Language Teaching in Language Classrooms

Communicative Language Teaching (CLT), also known as communicative approach, has witnessed a tremendous growth of research since it was developed by British applied linguists, as an effective approach to L2 learning and teaching. The basic idea of CLT is that language instruction should focus on communicative proficiency instead of on mere mastery of structures. With the guidance of five interconnected principles summarized by Richards and Rodgers, various implementations are realized. However, the implementation of CLT in Asia still encounter a number of difficulties due to some conceptual and contextual mismatches. In the short discussion of CLT, its background, definition, main characteristics as well as its strengths and limitations are contained. The article aims to help foreign language teachers to acquire a comprehensive understanding of CLT and adapt their teaching beliefs to cope with the challenges in practical teaching.

Experimental Characterization and Numerical Simulation of a Low-Scale Personal Cooling System with Integrated PCM

Phase Change Materials (PCMs), among the existing thermal storage technologies, are characterized by higher storage densities than conventional storage systems, and absorb and release thermal energy at nearly constant temperatures. In recent years, the potential advantages that can be obtained by the integration of these materials into refrigeration machines have attracted the attention of specialized literature. Indeed, PCMs can allow a more efficient operation through an appropriate increase in thermal inertia, for applications relative to air conditioning in both internal residential environments and inside vehicles for the transport of people, and also in the case of machines used in the field of food refrigeration. Furthermore, in recent years, innovative solutions with integrated PCM have also been analyzed, aiming at enhancing the usability and transportability of refrigeration systems, as well as increasing the energy efficiency and reducing environmental impact. In this context, the present work focuses on the experimental characterization and numerical simulation of a cooling system with integrated PCM. In particular, the cooling system, designed for a personal cooling application, is experimentally analyzed by varying the configuration of the PCM-based condenser, while the numerical simulations have been realized to validate a simulation tool that could be used for the design and optimization of the PCM condenser configuration. The results allow us to identify the main characteristics of the analyzed personal cooling system, namely, the cooling capacity and operating autonomy, and to point out the utility and the limits of the developed simulation tool. Among the various configurations analyzed, the best one in terms of refrigeration power and autonomy is the one characterized by the highest heat transfer surface of the heat exchanger, with the refrigerant compressor at 50% power.

A Comprehensive Study on Paddle Wheel Aerator

The aquatic biome is greatly impacted by the rise in demand brought on by the current worldwide population growth. The demand for fish is steadily rising with population growth and the prevalence of water contamination is rising alarmingly. Several aerators have been utilized to evaluate the normal aeration effectiveness at different conditions. In terms of oxygen transmission and water circulation, paddle wheel aerators fared better than the rest. The oxygen transfer capacity of the double-hub paddle wheel aerator was the same as that of the single-hub paddle wheel aerator but consumed more energy under similar geometric and dynamic properties. The dimensional analysis of the aeration process highlighted that the absorption process' determining parameter is KLA20 and the main characteristic of a paddle wheel aerator is its geometric variables. Generally, Paddle wheel design typically takes into account a variety of dimensions from 50 to 90 cm for the diameter, 75 to 135 rpm for speed, and 8 to 25 cm for paddle depth of submergence but certain performance losses were seen in the models. The power-to-volume ratio was calculated and found to be between 0.01 and 0.04 kW/m3 but the aeration process is affected by several geometrical and material variables. Despite the different kinds of aerators available in the market, the main issue is that farmers and other small stakeholders cannot afford them. Paddle wheel aerators with single or double hubs are pricey, while their counterparts need a significant initial outlay with lack of Automation and AI in aquaculture domain. Photovoltaic aerators also could not mitigate such anomalies completely as it outperforms in overcast days. This study highlighted the comparison and effectiveness of different types of aerators used and suggested that there is a pressing need to design aerators to solve these issues and make it affordable for small stakeholders.

Post-Human and Trans-Human in the Future Perspective of the Humanity


 
 
 The article considers the issue of chnging the main anthropic characteristics of a human under the influence of the rapid development of the latest technologies. Such changes cause the need to revise the usual interpretation of the concept of ‘human’, which is gradually being substituted by the currently popular concepts of ‘trans-’ and ‘post-human’. These concepts are favourably perceived by the techno-optimists, who believe that the latest technologies will allow us to create people who will be physically, intellectually and spiritually superior to the people of today, although they admit that this may lead to greater social inequality.
 The article states that the post-human potential is too ambiguous to clearly outline it. On the one hand, it opens up unprecedented possibilities, which can be considered the highest manifestation of human freedom, i.e. the ability to model a person according to one’s vision. On the other – there is a real threat to human existence itself, namely, the danger of technological capture of the potential for human improvement. Therefore, the task of the article is to outline the possible prospects for the formation and improvement of modern human identity under the conditions of its combination with the other, non-human species and the latest technologies. This is possible under the condition of acceptance of new possibilities for the post-human as the liberating force that overcomes the negativity and limitations of human nature.
 The comparative method and the method of analysis were used in the article.
 
 

Physiological Nitrogen Uptake and Utilisation Responses in Two Native Plants from the Qinghai-Tibet Plateau under Different Water and Fertiliser Conditions

Drought and poor soil quality are the main characteristics of extreme environments in arctic–alpine areas. Understanding how herbaceous plants in alpine grasslands maintain the normal supply and utilisation of nutrients under different rainfall conditions is key to maintaining population stability. In the present study, the native plants Poa crymophila and Stipa purpurea of the Qinghai–Tibet Plateau were used to conduct a controlled experiment involving water and fertiliser to analyse their physiological responses in terms of nutrient uptake and utilisation. The results showed that decreased soil moisture increased proline and non-structural carbohydrates in P. crymophila, mainly accumulating in the leaves and stems. Nitrogen (N) addition promoted proline accumulation, whereas nonstructural carbohydrate content decreased. However, the proline and non-structural carbohydrate contents of S. purpurea were less affected by water and fertiliser. Additionally, drought restricted rhizospheric and non-rhizospheric alkaline-hydrolysed N release, increased rapidly available phosphorus (RAP) content in rhizospheric soil, limited root growth, and reduced surface area, root length, and root volume. Both aboveground and underground N fertiliser utilisation rates decreased. Under well-hydrated conditions (WH), high N levels increased rhizospheric alkaline-hydrolysed N and urease activity while inhibiting RAP and activity of alkaline phosphatase contents, thereby limiting root growth and reducing N fertiliser utilisation. The results indicate that both plant species have relatively low overall nutrient requirements that are limited mainly by water availability. The addition of low amounts of fertiliser is beneficial for nutrient release and utilisation, improving their adaptability to arctic–alpine environments and their suitability and superiority in the community. This study has significant implications for nutrient management and ecological restoration measures in arctic–alpine grasslands.

Sexual Activity of Older Adults: A Systematic Review of the Literature

Objective: The goal was to conduct a literature review of studies that examined sexual activity in older adults. Method: A systematic search was conducted to identify studies that had examined sexual activity in adults aged 60 years and older. The main characteristics of each study and results were examined and reported according to PRISMA guidelines. Results: Sixty-three articles were found. These articles were classified into three main groups based on the results they presented: percentage of older adults that were sexually active; frequency of sexual activity; and type of sexual activities. The results show that older adults are sexually active, engage in frequent sexual activity, and participate in a wide variety of activities. Conclusions: Although older adults remain sexually active, differences in the way sexual activity is assessed limit the drawing of firm conclusions and our understanding of the sexual activity of older adults. We propose a series of recommendations to gain a better understanding of this topic.

The influence of the urban model on civic involvement and public time. A study applied to the commuting population of the Greater Metropolitan Area of San José, Costa Rica

A major problem for policymakers is to ensure that levels of citizen participation reflect the society in its diversity, but they must also ensure that those citizens who want to get involved have the means to do so. Despite empirical evidence of the role of urban planning in health, well-being, and livability, studies have not delved into the implications of how low-density sprawled urban forms influence civic involvement. This paper adds new evidence regarding the significance of urban form, built environment characteristics and more in general city planning, as intermediary factors between public and private life connected to civic engagement and public space use. Based on surveys and geographic data from the Greater Metropolitan Area of San José, in Costa Rica, the article investigates how the results of citizen participation change depending on whether residents are from a compact or dispersed study area, relating to urban rhythms and mobility metrics. Findings suggest that inhabitants of group A (lower-density neighborhoods) differ significantly from group B (compact-city areas) in four variables: means of mobility, commuting time, public space use, and civic activism, while having similar sociodemographic composition. Compared with residents of group A, group B report higher levels of use and knowledge of public spaces and civic participation. These two aspects constitute, the Urban Civic Participation Index, which, related to self-reported free time, forms what we define as Public Time. The main characteristics of the compact city (higher population and building density, high street connectivity, grid presence and proximity of services, mixed land use) were found to be positively related to the outcomes of accessibility to public space and community participation. In contrast, there are no significant differences in the availability of free time between the two groups. This study, along with others on the compact city, shows that there are other reasons to reduce daily commuting distances in cities and the need of urban time policies to redesign urban society's temporal dimension besides the known environmental impacts. It also raises the question of how low urban density affects people's time and disposition to participate in public life.

Recent Advances in Multi‐Scale Piezoresistive Interfaces for MXene‐Based Flexible Sensors

AbstractFlexible piezoresistive sensors hold great promise in biomedicine and personal motion detection, attracting significant attention from researchers. Particularly, two‐dimensional (2D) MXene has made remarkable strides in biomedicine, electromagnetic shielding, and other practical applications, due to its exceptional hydrophilicity, biocompatibility, mechanical properties, surface functional groups, and large specific surface area. The ease of composite material formation further makes it ideal for high‐sensitivity flexible sensors. This paper summarizes the principal structural configurations for the multi‐scale interfaces, performance assessment metrics, and the corresponding sensing mechanisms of flexible piezoresistive sensors. Subsequently, the main characteristics and synthesis methods of MXene, especially the related applications and parameters are introduced in detail. The research trends and typical applications of MXene‐based flexible piezoresistive sensors focused on film structures, fiber structures, 3D structures, and hydrogel structures, are highlighted systematically. In addition, the challenges and prospects that promoting the advancement of MXene‐based flexible piezoresistive sensors in future are also discussed, which will revolutionize the sensing field and offer a wealth of opportunities in biomedicine and beyond.

Chemical Profile of Cold-Pressed Beech Nut (Fagus sylvatica L.) Oil

The objective of this study was to assess the chemical characteristics of cold-pressed beech nut oil. The nuts, gathered from the forest, comprised 25.35% water, 13.19% oil, and 19.40% protein. The predominant fatty acid was linoleic acid (40.5%), followed by oleic acid (35.0%) and gondoic acid (7.7%). All four tocopherols were present in the oil, with γ-tocopherol being the dominant form at 99.38 mg per 100 g of oil. The total sterol content was 2708.73 mg per kg of oil, with β-sitosterol constituting 80.5% of all sterols. The main characteristics of the oil included its relatively high tocopherol and gondoic acid content, a dominant oleic–linoleic fatty acid profile, and elevated levels of carotenoids.