Terms Of Transport Research Articles

Shaping outcomes of Reciproc Blue and Rotate in roots canals with band-shaped isthmuses: micro-CT study.

This study assessed the outcome of shaping the mesial roots of mandibular first molars containing band-shaped isthmuses with an isthmus floor located at the apical third with Reciproc Blue and Rotate instruments in terms of canal transportation, canal aberrations and unprepared apical canals. Pair-matched mesial roots of mandibular first molars according to their isthmus location (distance from apical foramina) and size were constructed based on quantitative measurements (length, major and minor diameter at isthmus roof and floor) on preoperative micro-CT scanning (n = 10). The pair-matched specimens were prepared either using Reciproc Blue R25 (25.08v) or Rotate (15.04, 20.05, 25.06) instruments and then subjected to a second micro-CT scanning. Micro-CT scans were analysed to evaluate the canal transportation at the apical foramen and isthmus floor levels and the frequency of procedural errors (separated instruments, artificial canal preparation, cross shaping and unprepared apical canals). Canal transportation values were compared using Mann-Whitney U, and the distribution of procedural errors was compared with chi-square tests with a 5% significance threshold. Greater transportation values were detected in the apical foramen level compared to the isthmus floor in both groups. No significant difference was detected between Rotate and Reciproc Blue groups in terms of absolute transportation values and the incidence of procedural errors (p > .05). Preparation of mesial root canals containing a band-shaped isthmus at the apical portion with Reciproc Blue and Rotate instruments caused transportation of the original canal position at the isthmus floor and the apical foramen levels and resulted in procedural errors. This ex vivo micro-CT study using controlled pair-matched specimens showed that presence of a band-shaped isthmus complicates canal preparation procedure irrespective of the preparation systems.

Can high-speed railway promote regional market integration? Evidence from China

The rapid development of high-speed railways is an important manifestation of transportation modernization in China, and has a huge influence on the integration of China's regional market. The predominance of passenger transport in China's high-speed rail (HSR) network makes it difficult to explain the influence of HSR on regional market integration issues in the previous research paradigm of economic geography based on the iceberg costs theory. Therefore, this paper constructs a conceptual framework of HSR affecting regional market integration in terms of market access, information flow, and substitution transportation. It also empirically tests the HSR effect of market integration using prefecture-level data from 2003 to 2013 in China. The results show that HSR has a significantly positive effect on China's regional market integration, and the three influencing mechanisms exist. However, the influence of HSR on regional market integration is different due to the heterogeneity of economic development and population scale.

Urbanization and transport energy consumption in African countries.

Transport energy use contributes to pollution, so it generates negative externalities. This paper analyzes the effect of urbanization on the transport final energy consumption in African countries. To that end, the paper applies the panel threshold regression (PTR) model for a panel of 25 African countries over the period 1992-2017. The findings show that there is a significant positive relationship between total and per capita transport energy consumption and the share of the urban population in the total population. Thus, urbanization fosters transport energy consumption, either per capita energy consumption or total energy consumption. Therefore, the results from this study suggest that African countries should promote sustainable urbanization in terms of transportation.

Long-time asymptotics for coagulation equations with injection that do not have stationary solutions

In this paper we study a class of coagulation equations including a source term that injects in the system clusters of size of order one. The coagulation kernel is homogeneous, of homogeneity γ<1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma < 1$$\\end{document}, such that K(x, y) is approximately xγ+λy-λ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$x^{\\gamma + \\lambda } y^{-\\lambda }$$\\end{document}, when x is larger than y. We restrict the analysis to the case γ+2λ≥1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma + 2 \\lambda \\ge 1 $$\\end{document}. In this range of exponents, the transport of mass toward infinity is driven by collisions between particles of different sizes. This is in contrast with the case considered in Ferreira et al. (Annales de l’Institut Henri Poincaré C, Analyse Non Linéaire, 2023), where γ+2λ<1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma + 2 \\lambda <1$$\\end{document}. In that case, the transport of mass toward infinity is due to the collision between particles of comparable sizes. In the case γ+2λ≥1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma +2\\lambda \\ge 1$$\\end{document}, the interaction between particles of different sizes leads to an additional transport term in the coagulation equation that approximates the solution of the original coagulation equation with injection for large times. We prove the existence of a class of self-similar solutions for suitable choices of γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma $$\\end{document} and λ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\lambda $$\\end{document} for this class of coagulation equations with transport. We prove that for the complementary case such self-similar solutions do not exist.

Versatile bubble maneuvering on photopyroelectric slippery surfaces

Contactless bubble manipulation with a high spatiotemporal resolution brings a qualitative leap forward in a variety of applications. Despite considerable advances, light-induced bubble maneuvering remains challenging in terms of robust transportation, splitting and detachment. Here, a photopyroelectric slippery surface (PESS) with a sandwich structure is constructed to achieve the versatile bubble manipulation. Due to the generated dielectric wetting and nonuniform electric field under the irradiation of near infrared (NIR) light, a bubble is subject to both the Laplace force and dielectrophoresis force, enabling a high-efficiency bubble steering. We demonstrate that the splitting, merging and detachment of underwater bubbles can be achieved with high flexibility and precision, high velocity and agile direction maneuverability. We further extend the capability of bubble control to microrobots for cargo transportation, micropart assembly and transmission of gear structures. We envision this robust bubble manipulation strategy on the PESS would provide a valuable platform for various bubble-involved processes, ranging from microfluidic devices to soft robotics.

The Effect of Different Waste Material Binders in Relation to Khaya Senegalensis Solid Fuel Pellet Quality

Fuel pellets are an attractive renewable energy source derived from biomass sources thanks to their uniformity and ease of handling. However, raw biomass and waste material binders have several drawbacks, which include poor physical properties, particularly low density and compositional heterogeneity, which restrict their wider use as a general source of energy. Besides, due to the low energy density, low bulk density, and uneven shape and size of raw biomass, it is very difficult to store and transport biomass in its original form, which decreases transport efficiency. This study investigated the effect of waste material binders (rice husk, corn cob, and sugarcane bagasse) on the mechanical and thermal properties of Khaya Senagalensis pellets. The mechanical and thermal properties were determined according to ASTM standards. Waste material binders have affected pellet quality such as density, bulk density, moisture content, durability, compressive strength, shatter index, water resistance, ash content, volatile matter, fixed carbon, and calorific value. From the analysis, sugarcane bagasse as a binder shows the highest quality pellet in terms of mechanical properties. Sugarcane bagasse produces the highest density (0.967g/cm3), bulk density (0.4094), durability (99.71%), shatter index (98.85%), water resistance (98.35%), and thermal properties, which are the highest volatile matter (94.71%) and the lowest ash content (1.71%). In a nutshell, sugarcane bagasse is a good binder that gives a positive impact to the K.senegalensis pellets in terms of storage and transportation compared to corn cob and rice husk binder.

Value Chain Mapping of Edible Termites (Macrotermes subhylanus) as an Alternative Source of Income to Rural Livelihoods in Alego Usonga

Reducing food insecurity remains a public policy challenge in developing countries. Food insecurity becomes severe in areas where households highly depend on undiversified livelihoods. Entomophagy has been perceived as a solution towards food security due to its nutritional benefits, environmentally friendly attributes and its potential to generate income. However, information to aid its commercialisation is limited, hence the need for value chain mapping. This paper assesses the value chain of edible termites (Macrotermes subhylanus) in Alego Usonga Sub County with the aim of promoting it as an alternative source of income. This study sought to understand the value chain actors from input supplier to consumption and their role in the value chain. Simple random sampling was used to obtain participants for the study. Face-to-face interviews and structured questionnaires were administered to 225 respondents to collect data on value chain actors and their roles. Value chain mapping technique was used for functional and technical analysis of the alate termites’ value chain. The data was analysed using descriptive statistics Chi-square tests, with the aid of Statistical Package for the Social Science (SPSS) version 20. Value chain actors in the termite value chain included input suppliers (1.8), producers/collectors (4%), retailers (13.3%) and consumers (80.9). There was a significant difference (P ≤ 0.05) in terms of input supplier and producer/ collectors of termites; a high significant difference (P ≤ 0.001) was also recorded in hawkers and retailers, where women were reported to play a vital role in hawking and retailing of termites. In terms of transportation, human transport (82.7%) was preferred over motorbikes. Although the value chain actors agreed that edible termites could contribute to additional sources of income, the sector was insufficiently supported by farmer groups and associations, lending institutions, research, and extension service providers

Benthic biofilms in riverine systems: A sink for microplastics and the underlying influences

Rivers are known as major pathways for transporting microplastics from terrestrial areas to the marine environment. However, the behavior of microplastics in terms of retention and transport within riverine systems remains unclear. While considerable efforts have been made to investigate the water column and sediment, limited attention has been given to understanding the interplay between microplastics and benthic biofilms. Therefore, this study aimed to examine the distribution of biofilm-trapped microplastics along the CaoE River and identify the factors influencing the immobilization of microplastics by benthic biofilms. The findings of this study revealed that benthic biofilms served as a sink of microplastics in the CaoE River, with an average abundance of 575 items/m2 in tributaries and 894 items/m2 in the main stream. The dominant shape of microplastics was fiber, while the primary polymer type was polyethylene terephthalate. The distribution of microplastics exhibited significant spatial heterogeneity, as indicated by their abundance and characteristics. In order to reveal the intriguing phenomenon, variations of influencing factors were estimated, including physicochemical characteristics of water, extracellular polymeric substances of benthic biofilms, and microbial communities of benthic biofilms. A partial least squares path modeling analysis was performed using these variables, revealing that water velocity and microbial diversity of benthic biofilms were the key factors influencing the interaction between microplastics and benthic biofilms. In summary, this study provides substantial evidence confirming the crucial role of benthic biofilms in the immobilization of microplastics, which expands concerns about microplastic pollution in the riverine systems. Furthermore, uncovering the underlying influences of microplastic-biofilm interactions will facilitate the development of effective strategies for the control and management of microplastic pollution.

SPATIAL ANALYSIS OF TRANSPORT ACCESSIBILITY OF TOURIST INFRASTRUCTURE FACILITIES IN THE VOLOGDA REGION

Authorities pay increased attention to the development of autotourism, which can become a driver for the development of tourism in the country, being promising for development in all its regions. In the NWFD, these include the Vologda оblast, where much attention is paid to the development of tourism. In this regard, the purpose of the study was to determine the transport accessibility of tourism industry facilities for car tourists. For its implementation, general scientific research methods (analysis, synthesis, comparison) and spatial modeling were used. The object of the study was the tourist infrastructure of the Vologda Oblast, which includes collective accommodation facilities, catering establishments and tourist display facilities. The modeling carried out made it possible to identify objects that are inaccessible in terms of transport and to reveal their distribution pattern in the region. The scientific novelty of the study is the development of a methodological approach to assessing the transport accessibility of objects of tourist interest. The theoretical basis was the works of domestic and foreign scientists on the issue of assessing the transport accessibility of objects of tourist and social infrastructure. The information base is formed by statistical data, analytical materials and the results of sociological surveys on the problem under consideration. The research can be useful for federal and regional authorities when designing the placement of new points of tourist attraction to increase the level of transport accessibility of objects of tourist interest, which contributes to the development of domestic tourism in the region.

Investigation of bituminized waste products swelling behavior due to water uptake under free leaching conditions: Experiments and modeling

AbstractBituminized waste products (BWPs) were produced by conditioning in bitumen the co‐precipitation sludge resulting from industrial reprocessing of spent nuclear fuel. Underground geological disposal is a solution for the long‐term disposal of some intermediate level long‐lived (ILW‐LL) categorized BWPs in France. After one or several hundred thousand years, the water from the host rock will fully saturate the disposal cells. By an osmotic phenomenon enabled by the semi‐permeable capacity of the bituminous matrix, water in direct contact with BWPs could cause them to swell, which would lead to pressure on the host rock and may damage the disposal facility. Therefore, the BWPs’ swelling behavior has to be taken into account in safety studies for disposal facilities. This paper presents an experimental and numerical investigation of BWPs’ swelling behavior due to water uptake. Experimentally, water uptake, swelling and released salts were monitored for about 4 years during free leaching tests of simplified BWPs. The numerical model presented is extended from an existing one that incorporates transport mechanisms (diffusion, permeation, osmosis) with mechanics via Maxwell's viscoelastic model. An original coupled homogenization of transport terms is proposed to better capture the role of the semi‐permeable membrane played by the bitumen and the porosity dependency of coupled transport coefficients during water uptake. The presented numerical model is able to reproduce the experimental results of free leaching tests and shows its validity for the entire leaching process.

Research on the contribution of metro-based freight to reducing urban transportation exhaust emissions

Most carbon emissions come from cities, including mainly human activities in the fields of the urban economy, urban construction, and urban transportation. In terms of urban transportation, a truck produces far more carbon emissions than does a car. From the perspective of reducing the freight amount of urban road transport, underground logistics systems are a feasible solution in the future. Currently, metro-based freight is easier to implement, and the redundant transport capacity of the urban metro during off-peak hours can be put to good use. In addition, the pressure of the ground freight can be alleviated. Against the background of the coordinated operation mode of metro-based freight and ground freight, this study aims to measure the contribution of metro-based freight to reducing urban transportation carbon emissions by using the optimization method of metro passenger–freight coordinated transportation and traffic flow theory. Taking the Beijing Metro Batong Line as an example, the results of experiments show that the coordinated operation mode can significantly reduce urban transportation exhaust emissions.

Nonaqueous Liquid Electrolytes for Sodium‐Ion Batteries: Fundamentals, Progress and Perspectives

AbstractSodium‐ion batteries (SIBs), driven by sustainability and cost advantage, have been recognized as one of the most promising electrochemical energy storage devices. Electrolytes, as the most unique component that not only ionically connect while insulating electronically electrodes but also determine the eventual improvements in performance mainly regarding cycle life, Coulombic efficiency, energy density, and safety, hold the key to the practical implementation of SIBs. In this review, the fundamental design principles of Na+‐ion electrolytes and the chemical properties of the Na+ cation over the Li+ cation in terms of ion transport, salt dissolution, and solvation structure are first discussed. Then, a sequence of crucial experimental discoveries and strategical achievements in the field of electrolytes for SIBs are presented, with focuses on the ether‐based electrolytes for co‐intercalation into graphite, diluted and highly concentrated electrolytes, wide temperature range electrolytes, nonflammable electrolytes, indispensable electrolyte components (functional additives and new sodium salts). Finally, a detailed analysis of research trends of practically feasible Na+‐ion electrolytes is presented to aid in the ongoing quest for better SIBs of the future.

Determination of Combustion Characteristics of Densified Biomass Fuels from Agricultural and Domestic Wastes

The combustion characteristics of two carbonized biomass briquettes fuels samples (sample A and B) from two bio-wastes have been presented. Sample A is comprised of Agro-waste (residues) mainly rice husk, groundnut shell, corn cob, bagasse, rice straw, coconut coir, branches, wheat straw, maize husk, grass from the field, cassava stem while Sample B comprised of decaying domestic wastes material from wastes disposal/collection points mainly garbage, vegetables/fruits, protein, groundnut shell, maize cob, waste papers, all sorts of discarded foods etc. Analysis of briquettes fuels samples in terms of proximate analysis, ultimate analysis and calorific values were necessary to determine suitability of such material as reliable and sustainable energy sources. These parameters analyzed are unique fundamental code that characterizes and determines the properties, quality, potential applications and environmental problems related to any fuel. The result of the analysis placed sample B above sample A in terms of heating value. The proximate analysis indicated that the sample B had a better ignition characteristic at 77% volatile matter against 44% of sample A. Also, sample B have better heating value with fixed carbon 32% against 21% of sample A. This was also confirmed by ultimate analysis where sample B recorded a higher value of percentage Carbon and percentage Oxygen at 47.04% and 41.6% respectively. The bulk densities were in the range of 499kg/m2 to 502kg/m2 which is very good in terms of handling and transportation of the fuels. Moreso, calorific value of both samples were appreciably high at 18704 KJ/Kg for sample A and 18901.3 Kj/Kg by sample B. The ratio FC:VM for sample A is 0.477 which is higher than that of sample B, indicating that sample A will have a better yield and formation of biochar. Therefore the carbonised biomass briquettes are of good quality and exhibited good combustion properties as an alternative energy feedstock for domestic and industrial applications. It is a better source of energy for cooking, replacing fuel wood (firewood) and it is eco friendly.

До питання розвитку транспортних перевезень у регіональному аспекті

Today, globalization trends are becoming evident both in Ukraine and in the world. This approach is aimed at increasing urbanization and the development of agglomerations. Therefore, the issues of development of the transport industry of Ukraine in the regional aspect remain relevant. At the same time, it should be noted that modern multimodal transport networks have their own specific structure. A typical multimodal transport network includes modern components of such elements of the network of such types of transport as road, rail, air, river, sea. The authors identified multimodal transport hubs in the structure of the transport system of Ukraine, analyzed their efficiency in terms of freight and passenger transport. It has been established that the existing distribution of cargo and passenger transportation by modes of transport indicates a certain priority of the use of road transport for all types of communication. At the same time, it should be noted that the automobile mode of transport today in Ukraine and the world is not an example of efficient and economical use of energy resources, has a significant share of the environmental load among other modes of transport, and is not always the objectively optimal option for transporting goods and passengers according to the criteria of reliability, economy and delivery terms. Thus, given that the transport industry of any region, country and at the global level is an important component of the economy, attracts a large number of specialists and affects the pace of development of other sectors of the economy, it is necessary to carefully study the development of this industry at all levels of operation and constantly to direct its development along vectors that constantly change over time. The transport industry at the regional level should also be noted as the basis for building a developed and efficient transport industry in the country. The modern development of the international transport system shows that the gateway or hub can perform the functions of modal and intermodal convergence. Especially if it is a combination of two or more operating modes of different systems. At the same time, the currently operating structures of regional multimodal networks unite the main gateways (hubs), which ensures connection to the international transport system through the sea-land-air interface.

Evaluating the Progress of Renewable Energy Sources in Poland: A Multidimensional Analysis

Energy is a key driver of all modern economies. Sustainable development is playing an increasingly important role both at regional and local levels. It is a compromise between social and economic needs and the preservation of nature. In the policy of the European Union, the idea of sustainable development and environmental protection is of decisive importance for the implemented programs and economic activities. Contemporary challenges require the transformation of the energy market towards greater use of renewable sources. According to Directive 2009/28/EC of the European Parliament and European Council on promoting energy from renewable sources, Poland has committed itself to achieving a 23% share of renewable energy in gross final energy consumption by 2030. This goal considers total energy consumption in terms of power, engineering, heating, refrigeration, and transport. The aim of this paper was, firstly, an analysis of the share of renewable energy in the European Union over an 18-year period (2004–2021), with particular emphasis on the position of Poland. The second objective was the analysis of renewable energy at the local level in Poland, i.e., at the local government unit (LAU) level. Changes in the share of renewable energy in Poland compared to other European countries were also examined. The study utilized functional analysis of principal components and cluster analysis based on the data from the Central Statistical Office and EUROSTAT. The study found that while Poland does not differ significantly from other countries in using renewable energy, it does fall below the European average. Principal component analysis suggests that Poland responds adequately to European changes in the share of renewable energy in total energy consumption. This dynamic is stable (over 95% explained by the first component) and applies to most countries surveyed. In addition, the authors sought to answer questions relating to the current status of renewable energy sources in Poland, the barriers and challenges facing the introduction of renewable energy in the country, a comparative analysis of Poland’s progress in renewable energy with other global counterparts, and an exploration of the future prospects and potential for the development of renewable energy in Poland. The study found that the potential for renewable energy is greatest in the northern areas of Poland, with photovoltaics and wind power plants providing the greatest capacity. Poland’s renewable energy potential is very high and will be determined by technological development, political, economic, and social issues.

The South Seas and Islands in Vietnam’s Maritime Strategy: Position and Development Potential

Over 1,000 kilometers of islands and archipelagos make up Vietnam’s southern coastline. The following points are emphasized in the article based on surveys and secondary sources: (1) the benefits of the Southern Sea and Islands’ geographic location, environmental conditions, and natural resources; (2) the Southern Sea and Islands’ role in Vietnam’s marine economic development strategy; and (3) approaches to the sustainable development of the Southern Sea and Islands in Vietnam’s overall marine and island development strategy. The findings of the study indicate that the Southern Sea and Islands have abundant and diverse potential in terms of energy, maritime transport, ecosystems, and tourism, serving as a critical location for national security and defense for the region and the whole country. The development of marine and island values in the southern region of the country is a key component of Vietnam’s marine economic development strategy, which also emphasizes harmonious growth. Focusing on synchronized and harmonious actions is essential in the process of taking advantage of the Southern Sea and Islands’ benefits for the process of global economic integration. It is also important to promote the involvement of numerous economic sectors in the process of utilizing and sustainably growing the marine economy.

Fog Intelligence for Secure Smart Villages: Architecture and Future Challenges

The Internet of Things (IoT) technology is considered the foundation for next-generation smart villages due to its ability to use sustainable information and communication technologies. The smart villages can enable real-time data analytics and can automate decision-making for local villagers in terms of agriculture, health care, transportation, environment, and energy. However, most of the wireless sensing devices exchange information using public networks and therefore may not be able to resist all forms of attacks. Additionally, most of the IoT devices are resource restricted and use cloud servers to process and store data. However, when IoT devices communicate with cloud computing data centers, the volume of data causes network congestion. To provide secure services close to end devices, a new network architecture called Distributed Fog Computing (DFC) can be created and integrated with IoT-based smart villages deployment. Motivated from the aforementioned discussions, this article explores the integration of DFC with IoT in improving security and privacy solutions for villagers and Consumer Electronic (CE) devices. As a case study, we also design and evaluate the performance of an Intrusion Detection System (IDS) in DFC-based smart village environment. Finally, we discuss several open security issues and challenges regarding Fog-to-Things enabled smart villages.

Experimental Study of Secondary Flow in Narrow and Sharp Open-Channel Bends

Secondary flow is a prominent feature of channel bends; it alters the streamwise velocity and bed shear stress distributions. Experiments were conducted to investigate the complex pattern of secondary flow in a narrow and sharp open-channel bend and the underlying mechanism of generation of multiple circulation cells. Compared with the moderate bends, the sharp bends are characteristic of multiple circulation cells from the 90° section. In addition to the curvature-induced circulation cell (S1) and turbulence-induced counter-rotation circulation cell (C1) near the outer bank, another circulation cell (S2) was observed near the inner bank and was attributed to flow separation. A term-by-term analysis of the vorticity equations indicates that the centrifugal term favours S1 and C1 while opposing S2. The turbulence-related term accounts for the formation of C1 and S2. The advective transport term redistributes vorticity and maintains the existence of S2. The dependence of secondary flow structure on Reynolds number and aspect ratio was also explored. With an increase in the Reynolds number from 23000 to 37000, both the strength and size of C1 are reduced by 50%, whereas the size of S2 increases by 20%, and its strength slightly decreases. With a decrease in the aspect ratio from 3.3 to 2, the strengths of S1, S2, and C1 are doubled, and the sizes of C1 and S2 increase by 90% and 20%, respectively.

A Novel Stack Approach to Enable High Round Trip Efficiencies in Unitized PEM Regenerative Fuel Cells

A Unitized Reversible Fuel Cell (URFC) system provides many benefits for energy storage by combining a fuel cell and an electrolyzer into a single stack, thus simplifying the system while decreasing weight, footprint, and material costs. URFC systems usually have low overall efficiency due to conflicting optimal operating conditions required for electrolyzer and fuel cell. This study optimized the membrane electrode assembly of the proton exchange membrane cell components to achieve 50% round trip efficiency and reliable performance under relevant duty cycles.Several components have been studied in this project including membranes, bifunctional catalysts for oxygen reduction and evolution reactions and porous transport layers (PTL). Different strategies have been applied to increase the overall performance of the stack while maintaining a low degradation rate. In particular, we looked at reducing the thickness of membranes as well as increasing the operating temperature. A comprehensive study of bifunctional catalyst has been carried out by varying the ratio of catalysts suitable for OER and catalysts suitable for ORR. Variation of the hydrophilicity of the PTL has been done to identify the optimum amount in terms of water and gas transport in the layers for both modes of operation.

THE STATUS OF ELDERLY PEOPLE'S EXPECTATIONS FOR THE CONSTRUCTION OF HOUSING AND PUBLIC AREAS

Many problems come to the fore with urbanization, urban transformation, and the increasing elderly population. For urbanization to be realized by taking the elderly population into account, the opinions of the elderly should be considered. This research aims to focus on the approaches of the elderly to the phenomenon of urbanization. For this purpose, in-depth interviews were conducted with 17 participants with a semi-structured interview form. Socio-demographic data were analyzed with IBM SPSS 26. In order to support the findings, the prominent statements of the participants were directly quoted. Considering the prominent findings according to the analyzes made, it is seen that the participants need help in terms of transportation, the availability of places to socialize, neighborly relations, and the existing physical conditions of the houses. As a result of the study, suggestions were presented to academicians, field workers, researchers, and local governments working in the field of aging.