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Found 6319 publications

Mapping quality linkages based on tacit knowledge

Thomas Bernhard Ladinig Gyula Vastag

Publication Name: International Journal of Production Economics

Publication Date: 2021-03-01

Volume: 233

Issue: Unknown

Page Range: Unknown

Description:

A structured conceptualization method, concept mapping, is applied to visualize the conceptual domain of explicit and tacit quality linkages in a complex, causally ambiguous production system of a premium automotive OEM. Experts, intimately familiar with all facets of the conceptual domain, defined sources of quality problems and rated their impact on product quality. These inputs, formative measures for a latent construct, were used to create concept maps and clusters for the sources of quality problems. Differences and disagreements between subgroups were highlighted by pattern matching. The concept map and the preferred cluster solution, based on user-defined measures, served as inputs in the development of a causal loop diagram and an action plan for better resource allocation to specific improvement activities. The approach, using formative rather than the more commonly used reflective indicators, uses key informants and explanation building processes of high internal validity. In the spirit of the “proximal similarity model,” the presented methodology is also highly transferable to similar settings of other automotive OEMs and beyond.

Open Access: Yes

DOI: 10.1016/j.ijpe.2020.108006

A novel preparation method of polypropylene/natural rubber blends with improved toughness

László Lendvai

Publication Name: Polymer International

Publication Date: 2021-03-01

Volume: 70

Issue: 3

Page Range: 298-307

Description:

A novel melt compounding method – originally introduced for the preparation of nanocomposites – was adapted to produce polypropylene (PP) based blends toughened with up to 20 wt% natural rubber (NR). This water-assisted technique is based on batchwise melt mixing, where the additives are introduced as an aqueous dispersion into the matrix, drop by drop. The efficiency of this preparation technique was analyzed by comparing the resulting blends with reference samples produced by traditional melt mixing. Mechanical, thermomechanical and morphological properties were determined in order to investigate the structure–property relationships. According to SEM analyses, the average domain size of NR within the PP matrix became significantly smaller when the water-assisted method was applied. Charpy impact tests showed that the toughening efficiency of NR particles within the PP was enhanced as a result of their decreased size. This improvement was more prominent when the difference between the viscosity of PP and NR was higher. In addition, applying the water-assisted technique led to an enhanced deformability with similar strength and stiffness compared to common melt mixing. © 2020 The Author. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.

Open Access: Yes

DOI: 10.1002/pi.6133

Minimizing Freshwater Usage in Batch Process Scheduling: S-Graph Approach

Máté Hegyháti Olivér Osz Dominic C.Y. Foo

Publication Name: Process Integration and Optimization for Sustainability

Publication Date: 2021-03-01

Volume: 5

Issue: 1

Page Range: 31-42

Description:

Water is one of the most important natural resources of life. While it is considerably cheap and vastly available currently, except for extreme locations, this is not guaranteed in the future. Being provident with water has multitude of advantages in both short and long term. Using less clean water not only brings immediate financial benefits, it simultaneously reduces wastewater production, related treatment costs, and the impact on the environment. Reducing the water footprint of a batch system is not a trivial task, as water sources and sinks need to be matched not only in quantity and quality, but in time as well. In this paper, the S-graph scheduling framework is extended to address simultaneous scheduling and water minimization in batch processing systems. The proposed approach tackles truly batch processes with a single contaminant, and allows only a single water source to be reused for each sink. The presented algorithm and S-graph extension have been implemented and tested on various case studies from the literature. The results of this paper provide an opportunity for further extensions to address a wider range of problems with multiple contaminants, semi-continuous behavior, cyclic operations, etc.

Open Access: Yes

DOI: 10.1007/s41660-020-00142-7

Sharing communities – Community currency in the sharing economy

Eszter Szemerédi Tatay Tibor

Publication Name: Society and Economy

Publication Date: 2021-03-01

Volume: 43

Issue: 1

Page Range: 38-59

Description:

For the further development and more efficient operation of the sharing economy, a fast and inexpensive peer-to-peer payment system is an essential element. The aim of this study is to outline a prototype that ensures the automation and decentralization of processes through smart contracts without blockchain technology. The model has been built based on the narrative that a community currency created through smart contracts can promote genuine practices of sharing as opposed to the profit-oriented approach that most of the currently operating sharing economy platforms have. Features of the model, such as ease of use, high-speed transactions without transaction cost are benefits that can provide a more efficient alternative to the traditional or to the cryptocurrency-based centralized sharing economy platforms.

Open Access: Yes

DOI: 10.1556/204.2020.00027

Mindset Patterns of Newcomers to Organic Farming in Hungary

Eniko Varga Zoltán Baracskai

Publication Name: European Countryside

Publication Date: 2021-03-01

Volume: 13

Issue: 1

Page Range: 38-55

Description:

Counterurbanization, rural in-migrant trend studies rarely focus on the individual decision-making process. This paper studies the mindset patterns and frames the decision to select organic farming as a next career. We aimed to deepen our understanding of the complex reasoning that motivatesnewcomers to choose organic farming on a personal level. Based on semi-structured interviews, we developed a questionnaire and collected data from the newcomer to organic farming community in Hungary. The responses were analyzed using: (1) factor analysis to assess the dimensionality of the factors and (2) knowledge-based expert system to identify the logical connections between the aspirations. Our conceptual model was developed based on if-then rules between the identified aspirations, which describe the mindset patterns of newcomers to organic farming.

Open Access: Yes

DOI: 10.2478/euco-2021-0003

Analysis of cross-border commuters’ spatial mobility between western regions of Hungary and Slovakia

Laszlo Vasa Lóránt Dávid P. Karácsony Mikhail V. Vinichenko Imrich Antalík

Publication Name: Geographia Technica

Publication Date: 2021-03-01

Volume: 16

Issue: 1

Page Range: 128-140

Description:

Commuting, defined as daily traveling for employment purposes, has gradually grown in importance in the past decades in Eastern European countries. According to Eurostat, although the freedom of movement may have encouraged cross-border commuting in the EU, it accounted just for 0.9% of the EU-28 workforce. Between the highest number of cross-border commuters, we can find Slovakian (147 thousand), and Hungarian (111 thousand) workers. We chose this topic because there has been a significant increase in the willingness to commute for economic reasons in recent years, and we want to explore the reasons of this. In the case of both examined countries, the inhabitants of the western regions are characterized by high willingness for cross-border commuting. Due to this reason, in own research, we conducted a questionnaire survey in the western regions of Hungary and Slovakia. The results indicate that there are similarities between Hungarian and Slovakian commuters. The regression analysis clearly showed that commuter satisfaction is most affected by the variety of jobs offered and the level of wages.

Open Access: Yes

DOI: 10.21163/GT_2021.161.11

Study of the TP transformation via the inverted pendulum example

Miklós Kuczmann Andrea Weber

Publication Name: Acta Technica Jaurinensis

Publication Date: 2021-02-24

Volume: 14

Issue: 1

Page Range: 1-23

Description:

This study decribes the Tensor Product (TP) based model construction through the nonlinear dynamic system of the inverted pendulum. It presents the steps of TP modeling, various weighting functions and the Linear Matrix Inequality (LMI) based approach. LMI control has been used to stabilize the nonlinear system. This study shows the quasi-Linear Parameter-Varying (qLPV) state-space modeling and the Higher-Order Singular Value Decomposition (HOSVD) based TP model transformation. Some research in this issue already exists, but only the furuta, rotary, single and parallel-type double pendulum have been examined. In this paper the TP model transformation of the inverted pendulum is analyzed in terms of stability.

Open Access: Yes

DOI: 10.14513/actatechjaur.00562

OEE measurement at the automotive semi-automatic assembly lines

János Jósvai Péter Dobra

Publication Name: Acta Technica Jaurinensis

Publication Date: 2021-02-24

Volume: 14

Issue: 1

Page Range: 24-35

Description:

Manufacturing companies continuously evaluate their achieved performance based on different Key Performance Indicators (KPI). This article gives an overview about the OEE values. The study aims to provide practical OEE data of semi-automatic assembly lines used in the automotive industry. Its novelty is the revealed relationship between seat assembly lines and seat subassembly lines. Firstly, a literature review shows the scientific relevance and several cases are collected to increase OEE percentage. Secondly, the connection between chassis, tracks, recliner and mechanism assembly lines is described. Each part of OEE (availability, performance, quality) are analysed in terms of their impact.

Open Access: Yes

DOI: 10.14513/actatechjaur.00576

Tutorial on the fragmentation of the railway ballast particles and calibration methods in discrete element modelling

Szabolcs Fischer Erika Juhasz

Publication Name: Acta Technica Jaurinensis

Publication Date: 2021-02-24

Volume: 14

Issue: 1

Page Range: 104-122

Description:

This paper presents a short literature review related to the fragmentation of the railway crushed ballast particles. With the help of the processed articles with the main topic of discrete element modelling (DEM) we aim to provide some insight into the international achievements and forward progress of the subject. Rock materials as granular elements can be investigated from several perspectives. The elements can be examined in laboratory conditions purely from the quarry, or even by obtaining already fragmented particles from the real railway tracks. In addition, DEM models can be created by using computer software. This article tackles only a small segment of the literature. Though each DEM topic was unique, they all involved examination of degradation of particles in some way. This review focuses on model building, including particle construction and calibration. The selected publications do not cover the current state of the entire DEM research related to ballast degradation.

Open Access: Yes

DOI: 10.14513/actatechjaur.00569