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Found 6374 publications

Investigation of the Effects of Biodegradable and Compostable Polymers as Sources of Microplastics on the Water-Soil Continuum: A Review

Gergely Zoltán Macher Dalma Bódizs Kornélia Horváth Anett Bedő

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 307-312

Description:

The amount of research and publications related to microplastic pollution has been steadily increasing in recent years, but at the same time, our current knowledge on the topic is still based on occasional point measurements. As a result of these point measurements, it becomes obvious that new research areas and disciplines are also connected to the topic of microplastics. Various biotic and abiotic processes can cause microplastics to enter the environment and spread within it. All of these mechanisms can arise from the moisture conditions of the tested medium, temperature differences, or even from the decomposing and transforming activities of microorganisms. The rise of biodegradable and compostable plastic bags can also be considered a source of this kind since polymer products labelled as environmentally friendly can be identified as secondary sources during their decomposition processes. Therefore, both industrial and household compost can contain microscopic polymer residues, the application of which involves a potential risk of environmental pollution. In recent years, several international studies have dealt with various aspects of the degradation of these products, including the use of problems caused by residual microplastics and their environmental effects. The focus of our paper is not on the development of a new scientific methodology but a summary of the current situation formed through research results dealing with the current environmental safety and environmental health risks of microplastic pollution caused by biodegradable polymers.

Open Access: Yes

DOI: 10.3303/CET23107052

Experimental study on the effect of filament-extrusion rate on the structural, mechanical and thermal properties of material extrusion 3D-printed polylactic acid (PLA) products

Imre Fekete László Lendvai Daniele Rigotti Alessandro Pegoretti

Publication Name: Progress in Additive Manufacturing

Publication Date: 2025-01-01

Volume: 10

Issue: 1

Page Range: 619-629

Description:

Material extrusion (MEX), also commonly referred to as fused deposition modeling (FDM) or fused filament fabrication (FFF) is currently one of the most commonly used additive manufacturing techniques. The quality of the 3D-printed objects fabricated by MEX methods highly relies on various printing parameters, one of which is the so-called filament extrusion multiplier (k). In this study, 3D-printed parts were prepared by MEX technique during which the material feeding rate was adjusted by varying the extrusion multiplier in the range of 97–105% (k = 0.97–1.05). The fabricated parts were tested for their geometrical, structural, mechanical, and thermal conductivity properties. Based on computed tomographic analysis and scanning electron microscopic images, increasing the k parameter resulted in smaller voids, along with gradually decreasing porosity (from 5.82 to 0.05%). Parallel to the decreasing defects, the thermal conductivity of the parts improved from 0.157 to 0.188 W/mK as determined by light-flash analysis technique. On the other hand, when k was set to ≥ 1.03 the geometrical accuracy declined, the size of the specimens considerably increased relative to the nominal values, especially in the X–Y directions due to excess material getting “squeezed” on the sides of the specimens. This latter phenomenon also resulted in the formation of a number of stress concentration sites, which manifested in the decrease of mechanical properties. Accordingly, the tensile, flexural, and impact strength of the samples improved up to k = 1.03; however, above that it dropped considerably.

Open Access: Yes

DOI: 10.1007/s40964-024-00646-5

Using multiple populations of memetic algorithms for fuzzy rule-base optimization

Krisztián Balázs Zs Dányádi Ĺaszĺo T. Ḱoczy

Publication Name: 11th IEEE International Symposium on Computational Intelligence and Informatics Cinti 2010 Proceedings

Publication Date: 2010-12-01

Volume: Unknown

Issue: Unknown

Page Range: 113-118

Description:

Evolutionary algorithms are an important branch of soft computing, being able to provide approximate solutions to problems in a reasonable amount of time. The underlying principle can be realized in an almost unlimited number of ways. This paper presents four main variants of evolutionary algorithms, and a method of running them in a topology consisting of multiple populations. The resources given to each population and migration are altered dynamically throughout the test, based on the effectiveness they show. Along with evolutionary methods, the solutions are also adjusted by gradient-based numerical optimization, in our case the Levenberg-Marquardt algorithm. These steps are added to the evolutionary processes as an extension, resulting in what are called memetic algorithms. The specific application for these methods here is optimizing fuzzy rule-bases, thereby making inference systems better at emulating a desired behavior, such as modeling a certain objective function. ©2010 IEEE.

Open Access: Yes

DOI: 10.1109/CINTI.2010.5672264

Processing systems design considering resilience

Ákos Orosz Jean Pimentel Ferenc Friedler

Publication Name: Computer Aided Chemical Engineering

Publication Date: 2021-01-01

Volume: 50

Issue: Unknown

Page Range: 807-812

Description:

The resilience of a system is defined as the system's capability of recovering from failures. Traditionally, only predictable aspects are considered when designing processing systems. Evaluation of these aspects is performed via assessment of exact indicators and enumeration of all cause-effect options. However, such evaluation is not appropriate for determining the resilience of processing systems, since resilience is based on unexpected events in addition to the expected ones. Consequently, the cause part of the cause-effect relation is not known or not effective. In the current work, the general formula for determining resilience of a system is embedded into a P-graph based process synthesis algorithm. Thus, the resilience can be considered when selecting the most preferred process during its synthesis. The result is illustrated by synthesizing a process of adipic acid production by nitric acid oxidation of KA oil.

Open Access: Yes

DOI: 10.1016/B978-0-323-88506-5.50126-1

Statistical Analysis of Companies' Logistics Systems

Antal Balogh Timea Kozma Attila Kurucz Marah Almelhem

Publication Name: Wseas Transactions on Business and Economics

Publication Date: 2025-01-01

Volume: 22

Issue: Unknown

Page Range: 2185-2197

Description:

COVID-19, officially SARS-CoV-2, which originated in China in December 2019, has fundamentally disrupted globalization and economic growth. The strain on supply chains is difficult to manage, and it is expected that the problems can only be resolved once the pandemic is over, which could lead to a further increase in economic and globalization growth. Consumer goods reach the final consumer through supply chains and supply networks, and these supply chains are increasingly playing a role in fostering collaborative relationships across international companies. As a result, companies are becoming stronger, more developed, and growing. Logistics is an important part of a company's operations, managing the flow of materials. The development and positioning of logistics within a company have a major impact on the company's performance, its role in the supply chain, and its competitiveness. Advanced, large companies now consider the senior manager responsible for material flow processes to be the head of the supply chain within their company, as the process from raw material to consumer must be managed and controlled as a whole. Performance must also be assessed in context, recognizing the differences between companies that give them a competitive advantage or disadvantage. In addition, the aim is to develop sustainable logistics at the company level, which will be achieved in companies that pay particular attention to the strategic role of logistics within the company. The use of statistical methods to analyze these relationships is not common in business practice, but it can provide important information and can also be a major aid to future decision-making.

Open Access: Yes

DOI: 10.37394/23207.2025.22.172

Design of Flat Loop Reactor with Bubble Column Circulation, Algae Growing Equipment

László Tolner Roland Jančo Imre Tolner

Publication Name: Strojnicky Casopis Journal of Mechanical Engineering

Publication Date: 2024-11-01

Volume: 74

Issue: 2

Page Range: 35-42

Description:

Based on the flow modeling and operational experience of the previous cylindrical loop reactor, we designed a sheet reactor combined with a loop reactor. The design with a cylindrical cross-section was applied to an equivalent cross-section (sheet) of several squares arranged next to each other. In accordance with the sedimentation processes experienced in the outlet branch, we created an algae trap, thereby reducing the flow to the level necessary for sedimentation. With this, I would like to achieve the already experienced, nearly 10-fold increase in algae concentration compared to the one in the mainstream.

Open Access: Yes

DOI: 10.2478/scjme-2024-0023

Investigation of viral diseases of garlic (Allium sativum L.), new primers for RT-PCR detection and diversity of garlic viruses in Hungary

László Palkovics János Ágoston Ádám Koczor János Ádám Katalin Salánki

Publication Name: Physiological and Molecular Plant Pathology

Publication Date: 2024-11-01

Volume: 134

Issue: Unknown

Page Range: Unknown

Description:

The study investigated the presence of potyviruses, carlaviruses, and allexiviruses in garlic samples, highlighting the impact of these viruses on garlic cultivation. No virus-free garlic was identified, with infections from at least one virus species observed in all samples. Notably, LYSV was detected in one sample, emphasizing the critical need for certified propagating material. Our study revealed the predominance of allexiviruses, particularly GarVD. Interestingly, no mixed carlavirus infections were detected. The results underline the risk of virus complexes, particularly when potyvirus infections occur alongside carla- or allexiviruses, exacerbating yield losses. The new primers we designed were successfully used, the usability of certain primers from earlier research has been confirmed, and new potential applications have been identified for some primers. In our study we have molecularly identified LYSV, GCLV, SLV, GarVB, GarVC and GarVD infected samples from Hungary, the presence of LYSV was confirmed with ELISA as well.

Open Access: Yes

DOI: 10.1016/j.pmpp.2024.102394

Comparison of High-Precision GNSS systems for development of an autonomous localization system

Huba Somogyi Alexandros Soumelidis

Publication Name: 2020 23rd IEEE International Symposium on Measurement and Control in Robotics Ismcr 2020

Publication Date: 2020-10-15

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

In the near future, the vehicles offering advanced driver assistance or fully autonomous operation. It will require increasingly accurate position information, available in all driving conditions and with 100 percent availability. In generally, a single sensor cannot meet these requirements alone and so it is necessary to use a combined sensor suite solution incorporating different kinds of sensors working together. As the only source of absolute position, velocity and time, Global Navigation Satellite systems (GNSS) play a critical role in next generation positioning systems. In this paper, we are dealing with modern GNSS solutions and presents the results of the comparison of two high-precision GNSS systems in different driving conditions and presents conclusion for the develop of autonomous localization system.

Open Access: Yes

DOI: 10.1109/ISMCR51255.2020.9263762

Designing assessment processes using the student involvement method by WTCAi system

Eniko Nagy Karl Eva Gyorgy Molnar

Publication Name: 2024 IEEE 22nd World Symposium on Applied Machine Intelligence and Informatics Sami 2024 Proceedings

Publication Date: 2024-01-01

Volume: Unknown

Issue: Unknown

Page Range: 237-241

Description:

The quality assurance of education and training is of paramount importance, and the monitoring, assessment and evaluation process is indispensable for this purpose. A key determinant of the effectiveness of education is assessment, which serves not only to measure performance but also to support the learning process. The process of assessment and evaluation must take into account the diverse needs and abilities of students. Differentiated assessment supports individual learning paths and personal development. Assessment must be objective and valid, but it can achieve its deeper developmental purpose when personalized. Our research aims to enhance pedagogical assessment efficiency by developing a machine learning-supported assessment system. The research focuses on developing STEM skills and analyzes children's questions to understand their interests and needs better. During the research, we observe the characteristics of questions posed by children and develop a machine learning algorithm that helps provide suggestions to educators for creating assessment questions. Based on the data, we identify children's areas of interest and the difficulty level of questions. According to the research results, children's questions can significantly differ from question sets prepared by educators, suggesting that children's diverse perspectives and interests should be given even greater consideration in teaching. The research also raises further directions for development. It aims to use machine learning to understand better the diverse ways of thinking and differences in expression among children, thereby making education and assessment more effective. This can contribute significantly to the efficiency and effectiveness of the teaching-learning process.

Open Access: Yes

DOI: 10.1109/SAMI60510.2024.10432808