Search in Publications

Found 6407 publications

Effect of Injection Molding Parameters on the Chemical Foaming of Acrylonitrile Butadiene Styrene (ABS) Using Breathing Mold Technology

Sándor K. Jakab Gabor Dogossy

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 247-252

Description:

Manufacturers have to adapt very quickly to the accelerating world and use specialized machines for production to meet the demands. This also means that those machines are not used as often as their mass-producing counterparts and sometimes become obsolete. In the case of foaming with injection molding, a complicated system has to be built around the machine and has to be structured in a specific way, which is not always cost-efficient. In this paper, two methods of chemical foaming of Acrylonitrile Butadiene Styrene (ABS) were performed on a regular injection molding machine. Chemical Blowing Agent (CBA) and Expandable Microsphere (EMS) were used with breathing mold technology. Injection molding parameters were modified, and specimens were produced for mechanical and morphological examinations. Properly selected parameters for foaming play an important role in retaining the mechanical strength of the product. With low switch-over volume and using the core-back method, it is possible to foam ABS using a Chemical Blowing Agent.

Open Access: Yes

DOI: 10.3303/CET23107042

SELF-ASSESSMENT OR PEER ASSESSMENT? WHICH IS BETTER PREDICTOR OF TEST RESULTS

Nárcisz Kulcsár

Publication Name: Sefi 2023 51st Annual Conference of the European Society for Engineering Education Engineering Education for Sustainability Proceedings

Publication Date: 2023-01-01

Volume: Unknown

Issue: Unknown

Page Range: 703-709

Description:

Internationally accredited engineering programmes are becoming increasingly important in the internationalisation agenda of universities. ABET has highlighted transversal skills in its accreditation criteria for engineering degrees. Preferred transferable skills include the ability of students to reflect on their own performance, the ability to give constructive feedback and the ability to make judgements. Students' self- and peer-assessment was examined in the context of a basic mathematics course. During the maths midterm tests, students self-assessed on each task, and assessed another student's test. These assessments were compared with the points given by the teacher. 84% of students overestimated their actual performance and more than 60% of them overestimated their peer's performance, and both overestimations were low. According to students' opinion, peer assessment is as easy as self-assessment, it is not easier for them to spot mistakes in other people's work than in their own. The research results showed significant difference in the accuracy of peer and self-assessment, peer assessment is closer to teacher evaluation than self-assessment. Contrary to our previous research, now we did not find a significant correlation between students' performance and assessment accuracy in the first test. One reason for this may be that these students have failed this subject at least once. As further learning is only possible once we have identified what needs to be learned, the ability to assess the gained knowledge as accurately as possible is appreciating. In addition to meeting accreditation requirements, the different type of assessments' cognitive and affective effects on learning outcomes make it a good choice for classroom use.

Open Access: Yes

DOI: 10.21427/HTNS-KS58

Application of the QFD Technique Method in Logistics Strategy

Péter Földesi Eszter Sós

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2023-01-01

Volume: 20

Issue: 2

Page Range: 145-164

Description:

One of the most significant corporate challenges today is to meet customer expectations. In order for customer satisfaction to be achieved, it is necessary to review the entire corporate system and related processes and coordinate the various corporate strategies. In the recent past, it was widely regarded as sufficient by managers to develop the right marketing strategy in order to sell a product. However, there is currently a discussion as to whether a marketing logistics strategy as a well-designed logistics environment is needed to sell the product and thereby gain customer satisfaction. In this article, we present the Quality Function Deployment (QFD) technique, an effective tool for transforming consumer needs into technical, quality characteristics. The method of QFD technique can also be successfully applied in the field of logistics. Utilizing it ensures the possibility of examining the impact of the sub-areas and processes of marketing and logistics services on the basis of customer needs. In addition, visual control can be used to illustrate that whilst two products require the same logistics strategy, lead times already cause significant differences in the interaction of logistics processes and technological parameters. The analysis also highlights the shortcomings of the logistics environment, thereby supporting the decision-making of the company management in both marketing and logistics strategy planning.

Open Access: Yes

DOI: 10.12700/APH.20.2.2023.2.8

Development opportunities for mobile and ICT learning in teacher education

Szilvia Petzné Tóth Bernadett Éva Pápai József Reider

Publication Name: Annales Mathematicae Et Informaticae

Publication Date: 2023-01-01

Volume: 59

Issue: Unknown

Page Range: 131-145

Description:

Learning is nowadays a continuous intellectual readiness to be able to cope with the current needs of the world of work. Students’ knowledge must be adapted accordingly and they must be capable of continuous development throughout their lives [8]. Changes in teaching-learning habits have already been observed at the beginning of the 21st century and those involved in education need to adapt to these changes with the appropriate transition to digital education what is more important today than ever be-fore. We asked our teacher-candidate students in an online questionnaire at the beginning and at the end of the “Teaching Methods in Mathematics” course. Our non-representative survey provided valuable data for course de-velopment. The aim of the survey was to find out students’ perceptions of the methods and tools they had learned in education. In the questionnaire at the beginning of the semester, we inquired our students about the types of work and methods they were familiar with, and then they gave their opinions about the different ICT tools, educational programmes and applications and how they were used. At the end of the semester, we interwieved them again whether they still held similar views on the subject or they had managed to change their views during the course.

Open Access: Yes

DOI: 10.33039/ami.2023.06.001

Methodology and Realization of Indoor Pass-by Noise measurement for passenger cars

Balázs Vehovszky Zsolt Gaszner

Publication Name: Journal of Physics Conference Series

Publication Date: 2023-01-01

Volume: 2677

Issue: 1

Page Range: Unknown

Description:

Nowadays the protection of human life is extremely important, and for this purpose the vehicles must go through a homologation process before the introduction to market. If we look at the acoustical requirements, one of the most important test procedures is the Pass-by Noise (PBN) measurement, which defines the noise emission limit value, when the observer stands beside the vehicle passing him by. There are two versions: Exterior (or Outdoor) and Indoor (or In-room) Pass-by Noise (IPBN) measurement. Former is presently the only accepted method for homologation; however, environmental and weather conditions could strongly influence its feasibility. For this reason, IPBN got into focus, with better suitability for development purposes and the prospect, that it will be accepted later for the homologation process too. This paper focuses on the IPBN method: gives an overview on the setup and presents the details of a realized test-measurement campaign. Beside the 2 most important points: the measuring room and the position of the sensors, the measurement devices, vehicle location and connection to measurement system, the measuring program and the whole process are presented together with some preliminary results related to different characteristics of the vehicle.

Open Access: Yes

DOI: 10.1088/1742-6596/2677/1/012004

Optimal Elasto-Plastic Analysis of Reinforced Concrete Structures under Residual Plastic Deformation Limitations

Szabolcs Fischer Majid Movahedi Rad Sarah Khaleel Ibrahim

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2023-01-01

Volume: 20

Issue: 1

Page Range: 45-62

Description:

In this study, an investigation regarding optimal elastic-plastic analysis method of different reinforced concrete (RC) structures is held by applying the residual plastic deformations limitations on the steel bars inside the reinforced concrete. Where different structures, including simple beam and slab, are selected as benchmarks and modelled numerically using ABAQUS in order to calibrate their experimental behaviour according to laboratory tests. Furthermore, concrete damage plasticity (CDP) constitutive model was applied to represent concrete behaviour in the numerical models considered. Then, an objective function was established for optimizing the applied plastic loads for each structure where the process of controlling plastic deformations was carried out by applying constraints on the complementary strain energy of the residual internal forces initiated inside the steel bars. This methodology was applied by authors by writing MATLAB code and linking it with ABAQUS to determine the corresponding applied plastic load for each entered complementary strain energy. Generally, applying optimization problem for each model showed that the complementary strain energy of the residual forces reflects the general behaviour of the structures and may be assumed as a constraint controlling the plastic behaviour of the structures whereas the obtained results indicated how structures acted differently when possessing different complementary strain energy values turning from elastic into elasto-plastic condition and then reaching plastic state.

Open Access: Yes

DOI: 10.12700/APH.20.1.2023.20.4

Validation Process of the Computer Simulation of a Test-Purpose Self-Driving Vehicle

Áron Ballagi Miklos Unger Rudolf Krecht

Publication Name: Iavvc 2023 IEEE International Automated Vehicle Validation Conference Proceedings

Publication Date: 2023-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

The aim of this article is to propose the initial validation steps for a test-purpose self-driving vehicle. The basis of the computer simulation in question is a passenger vehicle converted to be capable of specific self-driving tasks, meaning that it features a complete low-level control system, an onboard computer for high-level computation and a full sensor set consisting of laser scanners, lidars, cameras and GNSS receivers. The computer simulation of the described vehicle is created using the SVL Autonomous Vehicle Simulator and aims to completely model the behavior of the real transformed vehicle. To ensure the fidelity of the computer simulation, a set of comparative measurements are defined, which are realized using both the real vehicle and its computer simulation. The basis of comparison is, on one hand, the assessment of the vehicle control system by comparing control input and output, on the other hand, the comparison of onboard sensor measurement results.

Open Access: Yes

DOI: 10.1109/IAVVC57316.2023.10328107

GPS Based Navigation and Mobile Base Station of a Mobile Robot Platform

Rudolf Krecht Norbert Boros Dániel Eredits

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 385-390

Description:

One of the central challenges of today is to increase the degree of automation of the available systems and equipment in a sustainable way. This paper presents the development of an outdoor mobile robot platform navigation method, including an on-board unit and a mobile base station to support the operation of the ZalaZone Automotive Proving Ground in Zalaegerszeg, Hungary, by precise, automated deployment of traffic cones. Currently, traffic cone handling is a time- and labor-intensive job. Its automation saves a significant amount of human resources. As a first step, the technical requirements of the problem have been defined. Then, the navigation system that met the pre-defined requirements has been implemented. This paper presents the detailed development of this navigation system, including a description of the test phases as well. As part of the development process, the operation of a Global Navigation Satellite System (GNSS) receiver corrected by Real-Time Kinematic (RTK) is presented, supported by a small, low-power mobile base station, followed by a description of the applied hardware and software components, alongside with the alignment and further development of these components to achieve centimeter-accurate positioning. The Network Transport of Radio Technical Commission for Maritime Services (RTCM) via Internet Protocol (NTRIP) server facilitates the communication between the onboard unit and the base station via a 5G network. This work is continued by a detailed description of the autopilot system on the robotic platform, including the tools and software used for this purpose. The calibration process of the navigation system is described as well. Finally, the results and observations gained during the test are summarized and analyzed. These results have shown that the addition of an RTK system has highly increased the accuracy of a general GNSS receiver. In addition, these results underline the crucial role of 5G networks in the case of automated mobile applications.

Open Access: Yes

DOI: 10.3303/CET23107065

The Effect of the Dam-building Activity of the Eurasian Beaver (Castor fiber) on Changes in the Soil Moisture Conditions and Vegetation Associations of the Beaver Meadows in the Valley of Ablánc-stream

Gergely Zoltán Macher Dalma Bódizs Anett Bedő

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 319-324

Description:

Nowadays, more information is available about the activities of the Eurasian beaver (Castor fiber) as an ecosystem engineer species and the resulting ecosystem services. The environment-shaping activity of beavers not only affects the bed conditions of a given body of water but also affects the degree of diversity of the vegetation and fauna surrounding it. The research published in connection with this topic has only in recent years begun to deal more intensively with the condition characterisation and function analysis of the flooded areas under constant beaver influence, called beaver meadows. The focus of this paper is the investigation of beaver meadows directly connected to the dam system consisting of 19 beaver dams located along the Ablánc stream. The research examines the effect of the activity of the beaver colony, which has been continuously monitored for almost two years, on the soil moisture conditions of the beaver meadows in the Natura 2000 nature conservation area and to what extent this is reflected in the characteristics of the plant community. The focus of the analysis is the vertical distribution of soil moisture in the upper soil layer. During the vegetation mapping, 10 squares were designated to determine plant community parameters. High soil moisture values were detected in the examined quadrates, which varied between 39.0 φ% and a maximum of 50.0 φ%. A significant number of taxa could be identified - such as Myosoton aquaticum and Petasites hybridus - whose primary ecological requirements are a permanent wet environment and continuous water impact.

Open Access: Yes

DOI: 10.3303/CET23107054