Athens Journal of Τechnology & Engineering最新文献

{"title":"Transformation of the Acoustic Amplifier into a Modular Structure","authors":"Pawel Pienczuk, Jakub Wierciak","doi":"10.30958/ajte.10-4-4","DOIUrl":"https://doi.org/10.30958/ajte.10-4-4","url":null,"abstract":"The modular concept of device construction is most often based on the results of economic analyses. It allows lowering both manufacturing and design costs. It also improves their operating characteristics, in particular their repairability. It also happens that the modular structure of a consumer product is used to strengthen its market position. The authors of the article faced such a situation. The management of a company producing audiophile equipment decided to offer its potential customers an acoustic amplifier in which the user would be able to replace the preamplifiers himself, depending on the requirements related to the input signal. This type of modularity is known as \"component swapping.\" Before commencing the development of the structure, detailed analyses of the benefits and potential risks related to the individual stages of the product's life cycle were carried out: design, production and operation. On this basis, the \"Divaldi\" company, the manufacturer of the equipment, developed assumptions regarding the designed amplifier. In particular, it was considered that the modular system would be built by modifying the existing, successful design of the INT-02 amplifier. The modification will enable easy replacement of the two preamplifier sections. Users will have a choice of classic preamplifiers: line and phono, as well as modules integrated with an analogue-to-digital converter and a module with a Bluetooth receiver. A low-volume production was assumed from previously manufactured and stored components: the base and typical preamplifier sections. As for the exploitation stage, the possibility of self-replacement of modules by the user has been adopted. Based on these assumptions, the concept of an amplifier with two identical pockets was proposed, enabling the simultaneous installation and use of two preamplifier sect ions. Detailed requirements for interfaces between the modules and the base unit were formulated: mechanical and electrical. A review of the available types of signal connectors led to the selection of the PCIe connector as the one that best meets the technical and economic criteria. From the mechanical side, it was proposed to use sliding guides, guaranteeing proper positioning of the modules in the pockets of the base. After selecting and approving the solutions, constructions of the mechanical components of the system were developed, creating a new standard: frame, module pockets and preamplifier module. The successful implementation of the amplifier's modularity became the basis for formulating proposals for further modifications of the design to meet the growing requirements of users who expect more and more possibilities to adapt the structure and interfaces of devices to their own needs. Keywords: modularity, acoustic amplifier, customization","PeriodicalId":197899,"journal":{"name":"Athens Journal of Τechnology & Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139240591","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}

{"title":"Transforming CS Curricula into EU-Standardized Micro-Credentials","authors":"Kay Berkling, Till Hänisch, F. Schütz","doi":"10.30958/ajte.10-3-2","DOIUrl":"https://doi.org/10.30958/ajte.10-3-2","url":null,"abstract":"Micro-credentials are a way to integrate flexible learning pathways into the classic forms of education defined in the European Qualification Framework (EQF). They allow members of the workforce to get necessary skills described, certified, and recognized in a transparent and portable way. One way for universities to enter this market for lifelong learning is to convert existing study programs into smaller units, namely, micro-credentials. This process of converting a study program consisting of modules into small, independent pieces is called unbundling. When unbundling a program, the existing modules have to be converted to a standard EU-wide recognizable form. In this paper, we will describe the process we used to convert modules from our study program at DHBW. The first step converts the skill descriptions into a standard form. Since there is no common accepted formal standard, we use the Dublin descriptors as a way to structure the skills on the different abstraction levels, and ESCO-terms as a widely used standardized vocabulary. The second step breaks down modules of 3-12 ECTS into smaller constituents (each ECTS corresponds to a workload of around 30 hours). Typical micro-credentials have a size of 1 to 3 ECTS, a group or stack of micro-credentials corresponds to one module. Keywords: micro-credentials, curriculum design, internationalization, computer science, learning outcomes, standardization","PeriodicalId":197899,"journal":{"name":"Athens Journal of Τechnology & Engineering","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133450542","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}

{"title":"Quantifying Shallow-Depth Concrete Delamination using Impact-Echo","authors":"Mantaka Mahjabin Momo, N. Yazdani, Eyosias Beneberu","doi":"10.30958/ajte.10-3-1","DOIUrl":"https://doi.org/10.30958/ajte.10-3-1","url":null,"abstract":"Corrosion-induced concrete deck delamination is quite common in bridges. Locating these embedded delaminations is important to assess the extent of the damage, the remaining member capacity and any necessary rehabilitation. The impact-echo (IE) is a simple and straightforward non-destructive testing (NDT) technique by which the depth and extent of concrete delamination may be estimated. It is effective in detecting the location and determining the depth of relatively deep delaminations in concrete. Delaminations that occur near the concrete surface can also be detected by the IE method. However, the exact depth cannot be quantified due to difficulties in analysing the flexural mode that dominates the vibration response over the corresponding delaminated region. This study developed an IE-based procedure to quantitatively estimate the depth of shallow depth delaminations in concrete slab members. Four slab specimens were prepared, each with three artificial delaminations with varying shapes and sizes at shallow depths. The frequency contour maps showed good agreement with the actual location of the delaminations. The perimeter-to-depth ratio of the delaminated region can be used to analyze the flexural mode vibration frequency. Two equations are proposed that relate the depth of arbitrarily shaped delaminations to the flexural mode vibration frequency measured over the shallow-depth delaminations. Keywords: impact echo, concrete delamination, concrete slabs, flexural mode vibration, non-destructive evaluation (NDE)","PeriodicalId":197899,"journal":{"name":"Athens Journal of Τechnology & Engineering","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124646365","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}

{"title":"Time Effective Logistics of Hybrid Image Processing Course and Laboratory","authors":"S. Kosolapov","doi":"10.30958/ajte.10-3-4","DOIUrl":"https://doi.org/10.30958/ajte.10-3-4","url":null,"abstract":"In “pre-COVID 19” time, Braude Academic College of Engineering students enrolled in the course “Image Processing”, visited frontal lectures, and, additionally, participated in the laboratories provided in the class equipped with computers. During the laboratories, students (organized in small groups – preferably by pairs) were asked to implement several image-processing algorithms explained during frontal lectures. In the frames of this course, C, C++, and C# languages are used to write code. Specifically, to write the code, students used computers with Windows 10 and Visual Studio installed. Additionally, students were asked to prepare a PowerPoint presentation, in which they were asked to analyze the results obtained. During the in-campus laboratory, students were free to ask for help, and, in case of need, the educator provided relevant explanations. When the report was ready, students demonstrated the presentation and the working code to the educator. The grading policy was that if the presentation was good enough, and if students reasonably answered the questions, they got a high grade. As a backup, students E-Mailed a presentation and the code by using a special format developed specifically for that course. Because of COVID-19 limitations, during three semesters logistics of the lectures and laboratories were changed, and, as lectures, as laboratories were provided online by using cloud services like ZOOM and Gmail. It so happens, that semester 2021-10 – 2022-03 was started as an online semester, but after three weeks, it became a hydride semester: lectures and laboratories were provided in-campus, but students had the right to stay at home and continue to use cloud services including ZOOM and Email. This change created a number of logistics problems, and, thus, some modifications were provided in an attempt to ensure fair and non-biased grading as for the students who were physically present during the lectures and laboratories, as for the students who participated remotely. In the frames of this course, each group of students prepared a set of assignment reports and two micro-project presentations. Additionally, students physically present in the class, participated in the short nonobligatory micro-exams. This paper discusses logistics decisions and their effect on the quality of the students’ micro exams, assignments reports, and presentations. Keywords: hybrid laboratory, STEM, image processing","PeriodicalId":197899,"journal":{"name":"Athens Journal of Τechnology & Engineering","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131310309","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}

{"title":"Mathematical Model of HoloLens 2 Goggles Kinematics for AR Support of Flight Simulator","authors":"K. Cyran, Onyeka J. Nwobodo","doi":"10.30958/ajte.10-3-3","DOIUrl":"https://doi.org/10.30958/ajte.10-3-3","url":null,"abstract":"The paper describes how the kinematics model of HoloLens 2 goggles mounted on the user’s head is used for converting the reference frame fixed to the flight simulator with the reference frame fixed to the goggles. The constant correspondence between the two has to be kept to properly map the internal 3D space relative to the position of the device with the real 3D space of the flight simulator cockpit in which HoloLens 2 produces holographic objects. Such conversions are prerequisites of SLAM (Simultaneous Localization and Mapping) algorithms which are used by AR devices to build a map of an environment, and, at the same time, this map is used to compute the goggle’s own position and orientation. In the paper, we also present the application of HoloLens 2 goggles in the WrightBroS project to support flight simulator users (pilots and/or technicians) in their training and maintenance procedures. Keywords: augmented reality (AR), slam, kinematics, hololens 2, flight simulators","PeriodicalId":197899,"journal":{"name":"Athens Journal of Τechnology & Engineering","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125681074","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}

{"title":"Embodied Energy and Carbon Footprint of Concrete Compared to Other Construction Materials","authors":"H. Estrada, Luke S. Lee","doi":"10.30958/ajte.10-2-2","DOIUrl":"https://doi.org/10.30958/ajte.10-2-2","url":null,"abstract":"The main objective of infrastructure design codes is to protect the public’s welfare, health, and safety, none of which appear directly related to the current sustainability movement that has focused on protecting the natural environment, conserving resources, and minimizing the toxicity of construction materials and processes. Some United States jurisdictions have adopted language related to sustainability based on the United States Green Building Council to curtail adverse effects of global climate change, minimize environmental impact of new construction of built assets (i.e., buildings and infrastructure), and in some cases, improve air quality in the community. The focus of this paper is to compare the embodied energy and carbon footprint of various construction materials: concrete, steel, timber, masonry, and fiber reinforced composites. To properly compare these materials from a sustainability standpoint, we propose an index that characterizes material ecological properties by dividing strength and stiffness by embodied energy. The index is similar to the structural specific properties index used to characterize the mechanical properties of materials (i.e., strength and stiffness divided by density). Using this ecological index, concrete and steel appear to be the most sustainable materials. As a result of their higher strength and stiffness, concrete and steel require less embodied energy to satisfy specific structural demands. Keywords: embodied energy, carbon footprint, LEED, specific embodied energy","PeriodicalId":197899,"journal":{"name":"Athens Journal of Τechnology & Engineering","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127981417","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}

{"title":"Impact of Hull Fouling on Vessel’s Fuel Consumption and Emissions Based on a Simulation Model","authors":"Z. Pavin, Vlatko Knežević","doi":"10.30958/ajte.10-2-4","DOIUrl":"https://doi.org/10.30958/ajte.10-2-4","url":null,"abstract":"With an ever-increasing trend of analysing and improving vessel energy and economic efficiency in recent years and decades, every aspect of a vessel’s system needs to be observed with the goal of reducing fuel consumption and emissions. Hull fouling can have a significant effect on these variables. Since hull maintenance is an expensive effort, its use must be optimized and fine-tuned to increase the economic efficiency of a vessel’s exploitation cycle. In order to do this, data and a subsequent analysis have to be obtained on different stages of the hull fouling process and the effect these states have on vessel energy efficiency and consequently emissions and economic efficiency. This paper will analyse a set of data including emission pollutants such as nitrogen oxides (NOX) and carbon dioxide (CO2) as a greenhouse gas and the effect that different amounts of hull fouling have on the vessel’s fuel consumption and emissions under different propulsion loads. The aforementioned data is obtained from a simulation model of a RoPax vessel. The advantage of using data from a simulation model of a RoPax vessel for the research discussed in this paper is the ability to analyse various conditions not easily reproduced on actual ships. Main research findings presented in this paper are consistent in proving that increased hull fouling leads to increased fuel consumption and emissions as high as 15% increase in extreme cases. Keywords: hull fouling, fuel consumption, pollutant, greenhouse gas, emissions, simulator","PeriodicalId":197899,"journal":{"name":"Athens Journal of Τechnology & Engineering","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125483244","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}

{"title":"Utilising Magnus Effect to Increase Downforce in Motorsport","authors":"M. Lin, Patrick Lewis, P. Papadopoulos","doi":"10.30958/ajte.10-2-3","DOIUrl":"https://doi.org/10.30958/ajte.10-2-3","url":null,"abstract":"The Magnus effect is the generation of a sidewise force on a spinning cylindrical or spherical solid immersed in a fluid (liquid or gas) when there is relative motion between the spinning body and the fluid. This is most commonly seen in baseball, tennis, or European football where the ball’s trajectory is curved due to its rotation. The idea of using the Magnus effect in an airfoil to produce lift was proposed in 1941 in a patent application by Massey. This is also known as Kutta–Joukowski lift, first analyzed by Kutta and Joulowski in the late 19th century. In maritime applications, it is known as Flettner rotor sails, first used in the 1920's. Although Magnus effect is not new, the idea of using it on a racecar wing to improve downforce has not been extensively studied. The concept is to replace the front leading-edge of the wing with a rotating cylinder of the same diameter to produce additional circulation around the foil. This idea was born out of discussion at San Jose State University’s Formula SAE team as a way to create variable downforce on their wings. Although the idea was proposed but it was never built because of the complexity in the construction and a lack of rigorous analysis. Subsequently from our CFD simulation, it shows that by imposing a +2U angular velocity to the front LE cap (i.e., rotating upwards in the negative-x direction), we could gain 4.25% of downforce. Since the leading edge cap is roughly cylindrical, physically replacing it by a cylinder would not cause a visible change to the race car’s geometry while improving the aerodynamics using Magnus effect. This CFD data show promise to take the next step of building a physical prototype and perform aerodynamic experiments to validate this finding. Keywords: Magnus effect, aerodynamics, downforce, CFD, motorsport.","PeriodicalId":197899,"journal":{"name":"Athens Journal of Τechnology & Engineering","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132266782","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}

{"title":"An Experiential Engineering Learning Model for Knowledge and State of Flow Creation","authors":"R. Habash","doi":"10.30958/ajte.10-2-1","DOIUrl":"https://doi.org/10.30958/ajte.10-2-1","url":null,"abstract":"Education in professional degree programs is charged with serious responsibilities in the classroom and practice spaces. To meet these responsibilities, educators must serve as both teachers and learners in both spaces. This article demonstrates an experiential project-based learning model to enhance the teaching of an undergraduate engineering course on mechatronics. An important aspect of this model is an experiential learning model that complements the well-known international CDIO™ Initiative which is an innovative educational framework for producing the next generation of engineers. This model reflects on challenges of experiential learning for group-based design projects and faculty competition teams where learners including faculty and students collaborate to create their community of design and practice to physically and virtually share knowledge, perspectives, and opinions. The model reveals the impact of collaboration, practice spaces and exhibitions, and open educational resources in the enhancement of engineering education. The experience of adopting the model for several years recommends a number of practical approaches instructors may embrace to enable knowledge creation and enhance the effect of flow experience. Keywords: experiential learning, knowledge creation, reflective practice, state of flow, community of design and practice, open educational resource","PeriodicalId":197899,"journal":{"name":"Athens Journal of Τechnology & Engineering","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128767168","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}

{"title":"The Possibilities of Developing STEM Skills in Higher Education","authors":"Ildikó Holik, István Dániel Sanda","doi":"10.30958/ajte.10-1-1","DOIUrl":"https://doi.org/10.30958/ajte.10-1-1","url":null,"abstract":"The development of information and technology in recent decades has entailed a change of attitudes in higher education. In addition to academic knowledge, it is becoming increasingly important for students to acquire up-to-date, practical knowledge that will help them find their place in the world of work and in everyday life. Based on international analyses, the following characteristics, so-called soft skills, are essential on the labour market: higher-level thinking, communication skills, cooperation, self-control and a positive self-image. In our paper, we examine the possibilities of skills development in the field of STEM, especially in engineering education. In our university’s engineering teacher training, we strive to develop our students’ STEM skills using a variety of methods, and prepare them for the teacherly task of being able to effectively develop their own students’ skills and motivate them in STEM areas. This requires students to view their own learning process not as passive onlookers but as active participants. In our paper, we present some methods that can be effectively applied in STEM areas (e.g. discussion, collaborative learning, cooperative methods, project method, problem-based learning, inquiry-based learning, gamification, the use of robots in education). Keywords: STEM, skills development, educational methods, teacher training","PeriodicalId":197899,"journal":{"name":"Athens Journal of Τechnology & Engineering","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115672271","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}