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1.
Multicriteria assessment of the quality of waste sorting centers - ǂaǂ case study
Karmen Pažek, Jernej Prišenk, Simon Bukovski, Boris Prevolšek, Črtomir Rozman, 2020, original scientific article

Abstract: In this paper, the quality of the municipal waste sorting process in seven waste management centers in Slovenia was assessed using the qualitative multicriteria analysis (MCA) method DEX (Decision EXpert) implemented in DEXi software, which is based on multicriteria decomposition of the problem and utility functions in the form of ʺif-thenʺ decision rules. The study was based on eight types of secondary raw materials. The quality of the secondary raw materials, the regularity of the delivery of secondary raw materials to recycling units based on the sorting efficiency, and the loading weight of the individual baled fractions in the transport of secondary raw materials for recycling were the main parameters used in the model. The final assessment shows good waste management service in centers A and D. Centers B, C, and F were rated ʺaverageʺ. The ʺbadʺ rating was assigned to centers E and G.
Keywords: waste sorting, quality management, multicriteria decision analysis, expert system DEXi
Published in DKUM: 03.02.2025; Views: 0; Downloads: 2
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2.
A holistic approach to cooling system selection and injection molding process optimization based on non-dominated sorting
Janez Gotlih, Miran Brezočnik, Snehashis Pal, Igor Drstvenšek, Timi Karner, Tomaž Brajlih, 2022, original scientific article

Abstract: This study applied a holistic approach to the problem of controlling the temperature of critical areas of tools using conformal cooling. The entire injection molding process is evaluated at the tool design stage using four criteria, one from each stage of the process cycle, to produce a tool with effective cooling that enables short cycle times and ensures good product quality. Tool manufacturing time and cost, as well as tool life, are considered in the optimization by introducing a novel tool-efficiency index. The multi-objective optimization is based on numerical simulations. The simulation results show that conformal cooling effectively cools the critical area of the tool and provides the shortest cycle times and the lowest warpage, but this comes with a trade-off in the tool-efficiency index. By using the tool-efficiency index with non-dominated sorting, the number of relevant simulation cases could be reduced to six, which greatly simplifies the decision regarding the choice of cooling system and process parameters. Based on the study, a tool with conformal cooling channels was made, and a coolant inlet temperature of 20 °C and a flow rate of 5 L/min for conformal and 7.5–9.5 L/min for conventional cooling channels were selected for production. The simulation results were validated by experimental measurements.
Keywords: conformal cooling, injection molding, tooling, additive manufacturing, numerical simulation, non-dominated sorting
Published in DKUM: 05.12.2024; Views: 0; Downloads: 3
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3.
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Rationalisation of costs in the collection, segregation and transport of municipal waste
Paweł Zając, Ivona Bajor, Matevž Obrecht, Stanisław Ejdys, 2023, original scientific article

Abstract: The article contains answers to three "why" questions: - why the waste management system still does not bring the expected results, and the Polish state is one of the lowest-ranking in the European score regarding the amount of segregated waste; - why the sale of selected secondary raw materials and their material reuse in production processes do not cover the costs related to waste management; - why it does not bring additional profits. The article is based on research conducted in Wroclaw from 1998 to 2018. There is a cost model that can be adapted to similar cases. The article deals with removing organisational and/or technical reasons causing the stagnation of selective waste collection.
Keywords: waste, mixed, sorting, fee, management
Published in DKUM: 16.02.2024; Views: 204; Downloads: 20
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5.
On the role of anisotropy of membrane constituents on the elastic properties of highly curved lipid membranes
Šarka Perutkova, 2017, doctoral dissertation

Abstract: The primary objective of the thesis covers in the theoretical study the role of anisotropic membrane components in the elasticity of highly curved biological membranes. To show the importance of anisotropy, we focused on one type of non-lamellar membrane self-assembly - the inverted hexagonal phase and the membrane tubular protrusions with attached proteins. These two structures represent excellent examples of highly curved structures in which the anisotropy of molecules or small domains plays an important role. In the first part of the thesis, we developed a theoretical model describing the stability of the inverted hexagonal phase, which considers lipid anisotropy and deviations from the circularity of the pivotal plane cross-section. We applied a wedge-like model of phospholipid molecules, in which the phospholipid molecule is described as a wedge, with the angle of the wedge increasing with temperature. However, we also took into account the average orientation of lipids by including the deviatoric bending energy contribution derived from statistical physics. Theoretical predictions of our model showed that a crosssection of the inverted hexagonal phase is an intermediate between a circle and a hexagon, and that it has lower energy than the circular cross-section. The results were in agreement with observations gathered by the small angle X-ray scattering. By comparing our results with the experiments, we predicted some values of the mean intrinsic curvature and the phospholipid chain stiffness. In the second part of the thesis, we developed a theoretical model, which describes the stabilisation of membrane nanotubes containing attached anisotropic flexible rod-like proteins. We derived the free energy of a vesicle with nanotube taking into account the rotational averaging of the anisotropic attached proteins. We also added the entropy contribution due to the non-homogeneous lateral distribution of proteins. Our theoretical results showed that rod-like attached proteins and membrane domains can stabilise the membrane tubular protrusions if we consider the protein/ domain anisotropy. Our results were also in agreement with experimental results in which isotropic membrane constituents were found on the tips of the nanotube or on the mother vesicle; however, the anisotropic membrane constituents were detected along the nanotubes. Our results showed that rod-like attached proteins and membrane domains can stabilise the membrane tubular protrusions if we consider the protein/domain anisotropy. The anisotropy of membrane constituents can lower the membrane free energy in regions of high curvature. The main aim of the thesis was to show that the anisotropy of membrane constituents can lower the membrane free energy in regions of high curvature and that the rotational averaging of anisotropic membrane components should be considered in the evaluation of the membrane free energy at highly curved membrane structures.
Keywords: Biomembranes, Lipid anisotropy, Inverted hexagonal phase, Rotational averaging, Rod-like proteins, Membrane nanotubes, Membrane protein sorting
Published in DKUM: 25.05.2017; Views: 2372; Downloads: 109
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6.
An alternative sorting procedure for interactive group decision support based on the pseudo-criterion concept
Andrej Bregar, József Györkös, Ivan Rozman, 2003, original scientific article

Abstract: An original interactive procedure is proposed, which aims at overcoming some of the major weaknesses of existent pseudocriterion based methods for group decision analysis. It refers to absolute judgements of feasible alternatives and is focused on complementary activities of opinion elicitation and robustness analysis. As a foundation, four interdependent principles are introduced - problem localization, interactivity on the basis of aggregation/disaggregation approach, automatic derivation of criteria weights according to selective effects of veto tresholds, and group consensus seeking. The principles are grounded and realized by appropriate methodological solutions.
Keywords: decision analysis, pseudo-criterion concept, decision models, group consensus, alternative sorting, group work, fuzzy relation
Published in DKUM: 01.06.2012; Views: 1852; Downloads: 101
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