This article aimed to review the recent literature on the characterization of dietary fibers and their role in the human body, focusing on the methods of extraction of dietary fibers from agro-food waste as well as their use in various areas of the food industry. Dietary fibers are biologically active substances with beneficial effects on human health. Soluble dietary fiber is involved in reducing cholesterol levels and blood sugar levels, while insoluble dietary fiber helps regulate intestinal transit and maintain colon health. It would be useful to identify the extraction procedures and characterization of dietary fibers from agro-food waste. Fruit waste contains relevant amounts of bioactive compounds, such as: phenolic acids, flavonoids, lignins, carotenoids, etc. In addition, fruit waste contains significant amounts of dietary fiber with nutraceutical important activities, such as modulating the intestinal microbiota, lowering cholesterol, triglycerides and glycemic load in the blood. Hence, obtaining dietary fiber from agro-industrial waste can solve a number of economic and environmental problems that aim reducing waste, increasing the sustainability and profitability of companies in the Republic of Moldova. Dietary fiber can be used in various types of food, such as products of bakery and confectionery, meat, dairy products, and pasta. They can be used as stabilizers with an impact on food texture or ingredients with low caloric value, partially replacing caloric constituents such as fats, starch or sugars. Another important property is the prebiotic effect of dietary fibers. This property is determined by the fact that dietary fibers are indigestible or poorly digestible and are fermented selectively by intestinal microbiota, conferring health benefits to the host.
{"title":"POSSIBILITIES OF OBTAINING AND VALORIZING DIETARY FIBERS IN THE CONTEXT OF THE CIRCULAR BIOECONOMY","authors":"Svetlana Erşova, Daria Suhovici, Tatiana Ceșko, Maria-Marcela Barbaroș, L. Popescu, Aliona Ghendov-Moșanu","doi":"10.52326/jes.utm.2024.31(1).07","DOIUrl":"https://doi.org/10.52326/jes.utm.2024.31(1).07","url":null,"abstract":"This article aimed to review the recent literature on the characterization of dietary fibers and their role in the human body, focusing on the methods of extraction of dietary fibers from agro-food waste as well as their use in various areas of the food industry. Dietary fibers are biologically active substances with beneficial effects on human health. Soluble dietary fiber is involved in reducing cholesterol levels and blood sugar levels, while insoluble dietary fiber helps regulate intestinal transit and maintain colon health. It would be useful to identify the extraction procedures and characterization of dietary fibers from agro-food waste. Fruit waste contains relevant amounts of bioactive compounds, such as: phenolic acids, flavonoids, lignins, carotenoids, etc. In addition, fruit waste contains significant amounts of dietary fiber with nutraceutical important activities, such as modulating the intestinal microbiota, lowering cholesterol, triglycerides and glycemic load in the blood. Hence, obtaining dietary fiber from agro-industrial waste can solve a number of economic and environmental problems that aim reducing waste, increasing the sustainability and profitability of companies in the Republic of Moldova. Dietary fiber can be used in various types of food, such as products of bakery and confectionery, meat, dairy products, and pasta. They can be used as stabilizers with an impact on food texture or ingredients with low caloric value, partially replacing caloric constituents such as fats, starch or sugars. Another important property is the prebiotic effect of dietary fibers. This property is determined by the fact that dietary fibers are indigestible or poorly digestible and are fermented selectively by intestinal microbiota, conferring health benefits to the host.","PeriodicalId":52570,"journal":{"name":"Journal of Engineering Science","volume":"124 25","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141123789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Md Tanvir Siraj, M. Hasan, A. N. F. Ahmed, Faisal Bin Faruk, Md Foysal Ahmed, M. K. H. Chowdhury, S. M. F. Ahmed, Md Sohidul Islam, Kazi Sefat E Nur, Syed Salman Saeed
Bangladesh's Ready-Made Garments (RMG) industry, historically prone to hazards including boiler explosions with numerous fatalities, has prompted the RMG Sustainability Council (RSC) to initiate boiler safety inspections. This study addresses the lack of empirical data on boiler operations in RMG factories, focusing on operational scenarios, risk factors, and remediation strategies. Conducted from March 2021 to March 2023, structured visual inspections across 1386 RMG factories assessed 2204 boilers. Key findings reveal that 34.99% of factories predominantly use a single boiler, 91.24% of boilers are government-registered, and the majority are imported (63.29%) with a steam generation capacity below 1,000 kg/hr (59.75%). Additionally, 63.11% were manufactured between 2010 and 2019, 79.63% burn fossil fuels, 54.60% are vertically oriented, and 82% use softened feedwater. The study also identifies 32 external risk factors across 11 categories, providing insights for decision-makers to enhance boiler operation safety and sustainability. By leveraging this inspection data, the research aims to bridge the empirical gap and offer a comprehensive understanding of the existing challenges in RMG boiler operations. Journal of Engineering Science 14(2), 2023, 89-105
{"title":"Steam Boilers in Ready-Made Garments Industry in Bangladesh: Existing Scenario and Scope for Development","authors":"Md Tanvir Siraj, M. Hasan, A. N. F. Ahmed, Faisal Bin Faruk, Md Foysal Ahmed, M. K. H. Chowdhury, S. M. F. Ahmed, Md Sohidul Islam, Kazi Sefat E Nur, Syed Salman Saeed","doi":"10.3329/jes.v14i2.71233","DOIUrl":"https://doi.org/10.3329/jes.v14i2.71233","url":null,"abstract":"Bangladesh's Ready-Made Garments (RMG) industry, historically prone to hazards including boiler explosions with numerous fatalities, has prompted the RMG Sustainability Council (RSC) to initiate boiler safety inspections. This study addresses the lack of empirical data on boiler operations in RMG factories, focusing on operational scenarios, risk factors, and remediation strategies. Conducted from March 2021 to March 2023, structured visual inspections across 1386 RMG factories assessed 2204 boilers. Key findings reveal that 34.99% of factories predominantly use a single boiler, 91.24% of boilers are government-registered, and the majority are imported (63.29%) with a steam generation capacity below 1,000 kg/hr (59.75%). Additionally, 63.11% were manufactured between 2010 and 2019, 79.63% burn fossil fuels, 54.60% are vertically oriented, and 82% use softened feedwater. The study also identifies 32 external risk factors across 11 categories, providing insights for decision-makers to enhance boiler operation safety and sustainability. By leveraging this inspection data, the research aims to bridge the empirical gap and offer a comprehensive understanding of the existing challenges in RMG boiler operations.\u0000Journal of Engineering Science 14(2), 2023, 89-105","PeriodicalId":52570,"journal":{"name":"Journal of Engineering Science","volume":"67 50","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140486417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-29DOI: 10.52326/jes.utm.2023.30(4).07
Titu-Marius I. Băjenescu
Artificial intelligence (AI) is the ability of a machine to mimic human functions such as reasoning, learning, planning and creativity. AI enables technical systems to perceive the environment in which they operate, process this perception and solve problems, acting to achieve a particular goal. The computer receives data (either already prepared or collected via its own sensors, such as a camera), processes it and reacts. AI systems are able to adapt their behaviour to some extent, analysing the effects of previous actions and operating autonomously.
{"title":"WHERE IS ARTIFICIAL INTELLIGENCE GOING?","authors":"Titu-Marius I. Băjenescu","doi":"10.52326/jes.utm.2023.30(4).07","DOIUrl":"https://doi.org/10.52326/jes.utm.2023.30(4).07","url":null,"abstract":"Artificial intelligence (AI) is the ability of a machine to mimic human functions such as reasoning, learning, planning and creativity. AI enables technical systems to perceive the environment in which they operate, process this perception and solve problems, acting to achieve a particular goal. The computer receives data (either already prepared or collected via its own sensors, such as a camera), processes it and reacts. AI systems are able to adapt their behaviour to some extent, analysing the effects of previous actions and operating autonomously.","PeriodicalId":52570,"journal":{"name":"Journal of Engineering Science","volume":"72 38","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140486280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-29DOI: 10.52326/jes.utm.2023.30(4).08
R. Cadar, R. Boitor, M. Dragomir
The paper presents an example of successful reconversion of an industrial site located in the built-in area of Cluj-Napoca, Romania. This case study shows that land-use and transport integrated planning can be effectively implemented when a transport-oriented development (TOD) is designed for the redevelopment of an industrial site. Using TOD principles identified in the Romanian law and the technical criteria identified in the scientific literature, Sanex platform is analyzed to demonstrate it is a TOD. This would be the first documented TOD designed in Romania. A model is developed for TOD Sanex to estimate the impact that the redevelopment of the industrial platform into a multifunctional area will have on the local traffic. In this regard, two scenarios are analyzed – present scenario and future scenario after completion of the redevelopment. Two variants of the future scenario are discussed in connection to the Northern Mobility Corridor (CMN), the main project in implementation in the area, which is designed as a complete street. The results demonstrate that the induced traffic wouldn’t have a considerable impact on the local traffic now or in the perspective of the redevelopment. It can be integrated by the street network, which could operate in appropriate conditions. Considering the need of revitalization of the urban and rural industrial sites at the national scale in Romania and the benefits of TOD, a methodological framework in four steps is proposed. This framework would be a helpful support in the sustainable urban reconversion process, especially to achieve the reduced impact over the built environment and urban mobility.
本文介绍了罗马尼亚克卢日-纳波卡内置区一处工业用地成功改造的实例。该案例研究表明，在为工业用地的再开发设计以交通为导向的开发（TOD）时，可以有效实施土地利用和交通综合规划。利用罗马尼亚法律中确定的 TOD 原则和科学文献中确定的技术标准，对 Sanex 平台进行了分析，以证明其属于 TOD。这将是罗马尼亚首个有据可查的 TOD 设计。为 Sanex TOD 开发了一个模型，以估算将工业平台重建为多功能区将对当地交通产生的影响。在这方面，分析了两种方案--当前方案和重建完成后的未来方案。未来方案的两种变体与北部交通走廊（CMN）相关联，后者是该地区正在实施的主要项目，被设计为一条完整的街道。结果表明，无论是现在还是从重建的角度来看，诱导交通都不会对当地交通产生重大影响。它可以被街道网络整合起来，在适当的条件下运行。考虑到在罗马尼亚全国范围内振兴城市和农村工业用地的需要以及 TOD 的益处，我们提出了一个分为四个步骤的方法框架。该框架将为可持续城市改造进程提供有益支持，特别是减少对建筑环境和城市交通的影响。
{"title":"LAND-USE AND TRANSPORT INTEGRATED PLANNING AND MODELLING IN CLUJ-NAPOCA, ROMANIA","authors":"R. Cadar, R. Boitor, M. Dragomir","doi":"10.52326/jes.utm.2023.30(4).08","DOIUrl":"https://doi.org/10.52326/jes.utm.2023.30(4).08","url":null,"abstract":"The paper presents an example of successful reconversion of an industrial site located in the built-in area of Cluj-Napoca, Romania. This case study shows that land-use and transport integrated planning can be effectively implemented when a transport-oriented development (TOD) is designed for the redevelopment of an industrial site. Using TOD principles identified in the Romanian law and the technical criteria identified in the scientific literature, Sanex platform is analyzed to demonstrate it is a TOD. This would be the first documented TOD designed in Romania. A model is developed for TOD Sanex to estimate the impact that the redevelopment of the industrial platform into a multifunctional area will have on the local traffic. In this regard, two scenarios are analyzed – present scenario and future scenario after completion of the redevelopment. Two variants of the future scenario are discussed in connection to the Northern Mobility Corridor (CMN), the main project in implementation in the area, which is designed as a complete street. The results demonstrate that the induced traffic wouldn’t have a considerable impact on the local traffic now or in the perspective of the redevelopment. It can be integrated by the street network, which could operate in appropriate conditions. Considering the need of revitalization of the urban and rural industrial sites at the national scale in Romania and the benefits of TOD, a methodological framework in four steps is proposed. This framework would be a helpful support in the sustainable urban reconversion process, especially to achieve the reduced impact over the built environment and urban mobility.","PeriodicalId":52570,"journal":{"name":"Journal of Engineering Science","volume":"60 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140486744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heating, Ventilation and Air conditioning (HVAC) is an important part of residential structures such as single-family homes, apartment buildings, hotels and medium to large industrial and office buildings such as skyscrapers and hospitals, on ships, submarines and in marine environments.This paper investigates the characteristics of the performance HVAC system at “KUET auditorium” regarded as amphitheater for various internal and external conditions. A 2D model of the longitudinal section of the auditorium was drawn by using ANSYS-Fluent software in Design Modeler, for simulating the various functionality of the HVAC system for both summer & winter seasons. In this research, both the indoor & external conditions of KUET auditorium were considered, having the entire spectacle of hall is occupied by people. The main aim of this study was to observe the air temperature, air velocity and relative humidity for each case. The results are represented comparatively as graphs and spectra for various mass flow rates and indoor-outdoor temperatures. It was observed that the HVAC system provided sufficient human comfort conditions in terms of air flow and relative humidty recommended by (American Society of Heating, Refrigerating and Air Conditioing Engineers) AHRAE in the amphitheater for both the summer and winter season. Journal of Engineering Science 14(2), 2023, 01-14
{"title":"CFD Analysis on HVAC System Functionality in an Amphitheater","authors":"M. M. Rahman, M. Hasan","doi":"10.3329/jes.v14i2.71108","DOIUrl":"https://doi.org/10.3329/jes.v14i2.71108","url":null,"abstract":"Heating, Ventilation and Air conditioning (HVAC) is an important part of residential structures such as single-family homes, apartment buildings, hotels and medium to large industrial and office buildings such as skyscrapers and hospitals, on ships, submarines and in marine environments.This paper investigates the characteristics of the performance HVAC system at “KUET auditorium” regarded as amphitheater for various internal and external conditions. A 2D model of the longitudinal section of the auditorium was drawn by using ANSYS-Fluent software in Design Modeler, for simulating the various functionality of the HVAC system for both summer & winter seasons. In this research, both the indoor & external conditions of KUET auditorium were considered, having the entire spectacle of hall is occupied by people. The main aim of this study was to observe the air temperature, air velocity and relative humidity for each case. The results are represented comparatively as graphs and spectra for various mass flow rates and indoor-outdoor temperatures. It was observed that the HVAC system provided sufficient human comfort conditions in terms of air flow and relative humidty recommended by (American Society of Heating, Refrigerating and Air Conditioing Engineers) AHRAE in the amphitheater for both the summer and winter season. \u0000Journal of Engineering Science 14(2), 2023, 01-14","PeriodicalId":52570,"journal":{"name":"Journal of Engineering Science","volume":"16 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140489347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this article, the flow characteristics and linear stability of mixed convection in a ferrofluid layer are investigated. The fluid layer is positioned between two vertically oriented and differently heated nonmagnetic plates under an inclined magnetic field with non-zero gravity. This study involves the patterns of fluid motion, heat transfer, and the effects of the inclined magnetic field with gravitational action. The objective of this article is to analyze the flow characteristics of smaller Prandtl number of fluid and figure out the significant comparisons with larger Prandtl numbers of fluids. The characteristic of every instability mode is examined for a fluid having a different Prandtl number than the one that was previously investigated. The influence of buoyancy effects undergoes a notable transformation, shifting from a destabilizing role in flows dominated by gravity to a stabilizing role in flows characterized by stronger magnetic effects. It is found that in both normal and oblique magnetic fields, the basic flow evolves into a state of greater stability, and wave propagation is faster with lower Prandtl numbers of fluids than with larger Prandtl numbers of fluids. Journal of Engineering Science 14(2), 2023, 31-45
{"title":"Mixed Convection in Ferrofluids Vertical Layer with Inclined Magnetic Field","authors":"Md. Habibur Rahman, Mst. Lovly Khatun, Sushmita Mondal","doi":"10.3329/jes.v14i2.71213","DOIUrl":"https://doi.org/10.3329/jes.v14i2.71213","url":null,"abstract":"In this article, the flow characteristics and linear stability of mixed convection in a ferrofluid layer are investigated. The fluid layer is positioned between two vertically oriented and differently heated nonmagnetic plates under an inclined magnetic field with non-zero gravity. This study involves the patterns of fluid motion, heat transfer, and the effects of the inclined magnetic field with gravitational action. The objective of this article is to analyze the flow characteristics of smaller Prandtl number of fluid and figure out the significant comparisons with larger Prandtl numbers of fluids. The characteristic of every instability mode is examined for a fluid having a different Prandtl number than the one that was previously investigated. The influence of buoyancy effects undergoes a notable transformation, shifting from a destabilizing role in flows dominated by gravity to a stabilizing role in flows characterized by stronger magnetic effects. It is found that in both normal and oblique magnetic fields, the basic flow evolves into a state of greater stability, and wave propagation is faster with lower Prandtl numbers of fluids than with larger Prandtl numbers of fluids.\u0000Journal of Engineering Science 14(2), 2023, 31-45","PeriodicalId":52570,"journal":{"name":"Journal of Engineering Science","volume":"20 1-2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140490200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-29DOI: 10.52326/jes.utm.2023.30(4).03
Vadim Iatchevici, A. Toca, Tatiana Nitulenco, A. Stroncea
Technological development is largely determined by technology transfer, which is conditioned by the absorption capacity of new technologies, and new technologies are deeply digitized technologies. Success depends on creating basic digital skills, both technical and human, developing digital infrastructure, ensuring accessibility to digital technologies. In the context of Industry 4.0 technologies, the efforts to design products with pronounced physical-cybernetic elements are important, but especially those aimed at creating digital twins, gradually moving from intermediate variants of digital model and digital shadow. Digital twin creation models refer to the life cycle with emphasis on its stages. The paper proposes a digital twin model based on the technological function, in which the modification of the properties is manifested by restructuring the internal functions of the operator, operand and interface. The central place in this model belongs to the interface, which reflects the multitude of physical-technical processes at different scales of macro, meso, micro analysis characteristic of objects and processes in machine building.
{"title":"TECHNOLOGICAL TRANSFER UNDER THE CONDITIONS OF DIGITALIZATION OF PRODUCTS AND PROCESSES","authors":"Vadim Iatchevici, A. Toca, Tatiana Nitulenco, A. Stroncea","doi":"10.52326/jes.utm.2023.30(4).03","DOIUrl":"https://doi.org/10.52326/jes.utm.2023.30(4).03","url":null,"abstract":"Technological development is largely determined by technology transfer, which is conditioned by the absorption capacity of new technologies, and new technologies are deeply digitized technologies. Success depends on creating basic digital skills, both technical and human, developing digital infrastructure, ensuring accessibility to digital technologies. In the context of Industry 4.0 technologies, the efforts to design products with pronounced physical-cybernetic elements are important, but especially those aimed at creating digital twins, gradually moving from intermediate variants of digital model and digital shadow. Digital twin creation models refer to the life cycle with emphasis on its stages. The paper proposes a digital twin model based on the technological function, in which the modification of the properties is manifested by restructuring the internal functions of the operator, operand and interface. The central place in this model belongs to the interface, which reflects the multitude of physical-technical processes at different scales of macro, meso, micro analysis characteristic of objects and processes in machine building.","PeriodicalId":52570,"journal":{"name":"Journal of Engineering Science","volume":"210 3-4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140489963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-29DOI: 10.52326/jes.utm.2023.30(4).02
Stanislav Lealin
The requirements for the quality, reliability, and cost-effectiveness of engineering products and engineering production itself are constantly improving. As a result, there is an increasing demand for the quality of design and technological preparation of production, which includes classical dimensional analysis as its foundation. The Classical Method of dimensional analysis calculation represents a comprehensive set of computational and analytical actions carried out during the development and analysis of projects and technological processes, including: the construction of specialized dimensional diagrams for projects and technological processes, the identification and recording of interconnections between all dimensional parameters, the identification of dimensional chains, verification, and the establishment of rational sizing methods in drawings. Dimensional analysis involves a significant number of procedures and actions. The time required for dimensional analysis is substantial, ranging from 10 to 50 hours for a single technical drawing or technological process. At the same time, the use of Modern Methods for calculating dimensional chains will allow us to determine, after a thorough evaluation of manufacturing conditions at each production stage (operation), leading to a reduction in the manufacturing cost of parts. The increased workload of the evaluation process can be compensated by using databases and appropriate software that operates interactively with the user. This will also lead to a reduction in the labor intensity of dimensional analysis of projects and technological processes through automation.
{"title":"COMPARISON AND EVALUATION OF CLASSICAL METHODS OF DIMENSIONAL CHAINS THEORY AND THEIR MODERN ANALOGUES","authors":"Stanislav Lealin","doi":"10.52326/jes.utm.2023.30(4).02","DOIUrl":"https://doi.org/10.52326/jes.utm.2023.30(4).02","url":null,"abstract":"The requirements for the quality, reliability, and cost-effectiveness of engineering products and engineering production itself are constantly improving. As a result, there is an increasing demand for the quality of design and technological preparation of production, which includes classical dimensional analysis as its foundation. The Classical Method of dimensional analysis calculation represents a comprehensive set of computational and analytical actions carried out during the development and analysis of projects and technological processes, including: the construction of specialized dimensional diagrams for projects and technological processes, the identification and recording of interconnections between all dimensional parameters, the identification of dimensional chains, verification, and the establishment of rational sizing methods in drawings. Dimensional analysis involves a significant number of procedures and actions. The time required for dimensional analysis is substantial, ranging from 10 to 50 hours for a single technical drawing or technological process. At the same time, the use of Modern Methods for calculating dimensional chains will allow us to determine, after a thorough evaluation of manufacturing conditions at each production stage (operation), leading to a reduction in the manufacturing cost of parts. The increased workload of the evaluation process can be compensated by using databases and appropriate software that operates interactively with the user. This will also lead to a reduction in the labor intensity of dimensional analysis of projects and technological processes through automation.","PeriodicalId":52570,"journal":{"name":"Journal of Engineering Science","volume":"51 46","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140487252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-29DOI: 10.52326/jes.utm.2023.30(4).04
Rajat Nagpal, Maxim Chiriac, Alexandr Sereacov, A. Birnaz, N. Ababii, C. Lupan, A. Buzdugan, Iulia Sandu, Leonard Siebert, Thierry Pauporté, O. Lupan
The aim of this study was to develop low-powered, highly selective UV sensor to continuously monitor personalized UV exposure as well as to study annealing effect on UV detection properties of the sensors. ZnO:Al structures were obtained by chemical growth method followed by thermal annealing at 625 °C for 2 h. The studied samples exhibit maximal UV response of 620/488 at 25 °C/50 °C to 370 nm UV radiation before/after annealing, respectively. Thermal annealing of sensor (250 °C for 1 h) led to improvement in fall time from 3860 seconds to 262 seconds at 25 °C and highest responsivity (~48 mA/W) came out for 370 nm wavelength at 75 °C operating temperatures. Consequently, excellent selectivity for 370 nm UV illumination can be ascribed as due to thermal annealing effect which increases the crystallinity, grain size, and roughness of the sensing film. The PL measurements reveals the suppression of structural defects, increase in intensity after annealing and enhanced UV response due to presence of Al content in films. Overall, these structures showed magnificent UV properties, before and especially after additional thermal annealing. UV sensing mechanism of such nanomaterial-based sensor were explained with physio-chemical processes take place on the surface of these structures. The obtained results on annealed ZnO:Al films-based devices is superior to reported performances of other nanostructures, proving new results for UV sensing applications at different operating temperatures in various fields.
{"title":"ANNEALING EFFECT ON UV DETECTION PROPERTIES OF ZnO:Al STRUCTURES","authors":"Rajat Nagpal, Maxim Chiriac, Alexandr Sereacov, A. Birnaz, N. Ababii, C. Lupan, A. Buzdugan, Iulia Sandu, Leonard Siebert, Thierry Pauporté, O. Lupan","doi":"10.52326/jes.utm.2023.30(4).04","DOIUrl":"https://doi.org/10.52326/jes.utm.2023.30(4).04","url":null,"abstract":"The aim of this study was to develop low-powered, highly selective UV sensor to continuously monitor personalized UV exposure as well as to study annealing effect on UV detection properties of the sensors. ZnO:Al structures were obtained by chemical growth method followed by thermal annealing at 625 °C for 2 h. The studied samples exhibit maximal UV response of 620/488 at 25 °C/50 °C to 370 nm UV radiation before/after annealing, respectively. Thermal annealing of sensor (250 °C for 1 h) led to improvement in fall time from 3860 seconds to 262 seconds at 25 °C and highest responsivity (~48 mA/W) came out for 370 nm wavelength at 75 °C operating temperatures. Consequently, excellent selectivity for 370 nm UV illumination can be ascribed as due to thermal annealing effect which increases the crystallinity, grain size, and roughness of the sensing film. The PL measurements reveals the suppression of structural defects, increase in intensity after annealing and enhanced UV response due to presence of Al content in films. Overall, these structures showed magnificent UV properties, before and especially after additional thermal annealing. UV sensing mechanism of such nanomaterial-based sensor were explained with physio-chemical processes take place on the surface of these structures. The obtained results on annealed ZnO:Al films-based devices is superior to reported performances of other nanostructures, proving new results for UV sensing applications at different operating temperatures in various fields.","PeriodicalId":52570,"journal":{"name":"Journal of Engineering Science","volume":"15 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140488075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Rashid, M. M. T. Hossain, M. A. E. Akhter, M. A. K. Mallik
When temperature exceed 36 degrees with a large area and linger for minimum three or more days can be considered as heat wave (HW). In the Pre-monsoon, the sun ray drops down on the ‘Thar’ desert (India) and the foothill of the Himalayas vertically, the area makes a hot-tempered zone. That is why, these regions produce a trough of low and there is a possibility to advect temperature towards Bangladesh. The south/south westerly wind carries a high amount of moisture over Bangladesh. The heat capacity of moisture is higher than that of dry air. Solar insulation, temperature advection and moisture incursion are three main phenomena that are responsible for HW condition. Veering is also responsible for especially severe and very severe HW conditions. The present study is accompanying with all category’s frequency of heat wave days (HWD) and HW for the Pre-monsoon (March to May) over most of the stations (34) of Bangladesh for the period 1990-2019. Microsoft excel, Surfer and Arc GIS software have been used for data calculation, however, linear trend analysis and Mann-Kendall test have been used to draw the trend of HW frequency. The highest numbers of HWD are found in Jashore (30.9 days) of all types of events whereas the highest frequencies of HW are found in Rajshahi (4.2333) during pre-monsoon season. The lowest numbers of frequency of HWD and HW, both are found at Chattogram. April is the hottest month in Bangladesh. On the basis of frequency of HWD, the obtained highest hot places are Jashore, Chuadanga, Rajshahi, Ishurdi and Satkhira. while in Kutubdia and Teknaf, no HW is found at all. Among 30 years, 2014 is found the hottest year and 2018 is the recorded lowest hot year. By Mann-Kendall test, the HW trend of M. Court, Mongla, Patuakhali and Chandpur have indicated positive significant value, and Mymensing station has given only negative significant value. From spatial distribution, it shows the hottest areas which are south western and middle-western parts of Bangladesh. Journal of Engineering Science 14(2), 2023, 59-67
{"title":"A Study on the Heat Wave Conditions over Bangladesh During 1990 - 2019","authors":"G. Rashid, M. M. T. Hossain, M. A. E. Akhter, M. A. K. Mallik","doi":"10.3329/jes.v14i2.71227","DOIUrl":"https://doi.org/10.3329/jes.v14i2.71227","url":null,"abstract":"When temperature exceed 36 degrees with a large area and linger for minimum three or more days can be considered as heat wave (HW). In the Pre-monsoon, the sun ray drops down on the ‘Thar’ desert (India) and the foothill of the Himalayas vertically, the area makes a hot-tempered zone. That is why, these regions produce a trough of low and there is a possibility to advect temperature towards Bangladesh. The south/south westerly wind carries a high amount of moisture over Bangladesh. The heat capacity of moisture is higher than that of dry air. Solar insulation, temperature advection and moisture incursion are three main phenomena that are responsible for HW condition. Veering is also responsible for especially severe and very severe HW conditions. The present study is accompanying with all category’s frequency of heat wave days (HWD) and HW for the Pre-monsoon (March to May) over most of the stations (34) of Bangladesh for the period 1990-2019. Microsoft excel, Surfer and Arc GIS software have been used for data calculation, however, linear trend analysis and Mann-Kendall test have been used to draw the trend of HW frequency. The highest numbers of HWD are found in Jashore (30.9 days) of all types of events whereas the highest frequencies of HW are found in Rajshahi (4.2333) during pre-monsoon season. The lowest numbers of frequency of HWD and HW, both are found at Chattogram. April is the hottest month in Bangladesh. On the basis of frequency of HWD, the obtained highest hot places are Jashore, Chuadanga, Rajshahi, Ishurdi and Satkhira. while in Kutubdia and Teknaf, no HW is found at all. Among 30 years, 2014 is found the hottest year and 2018 is the recorded lowest hot year. By Mann-Kendall test, the HW trend of M. Court, Mongla, Patuakhali and Chandpur have indicated positive significant value, and Mymensing station has given only negative significant value. From spatial distribution, it shows the hottest areas which are south western and middle-western parts of Bangladesh.\u0000Journal of Engineering Science 14(2), 2023, 59-67","PeriodicalId":52570,"journal":{"name":"Journal of Engineering Science","volume":"119 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140486006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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