Iskanje po katalogu digitalne knjižnice

Opis: Companies rely on formulating, implementing, and monitoring strategies in social, environmental and economic aspects to ensure that they achieve their goals and keep abreast of developments related to sustainability requirements. Therefore, our study develops a system to integrate the closed-loop supply chain approach in the petrochemical sector. The research follows the quantitative-based approach by collecting data through a questionnaire directed to employees in the supply chain departments, including 230 questionnaires that were collected. Correlation and structural equation models (SEM) were used. This technique consists of multiple regression analysis and factor analysis and analyses the structural relationship between the underlying structures and the measured variables. The results indicated a significant relationship between the supply chains that have a loop from the following perspectives: economic motivations, customer awareness, environmental legislation, and sustainability. By increasing financial reasons, customer awareness and environmental legislation, sustainability will increase as they all move in the same direction. Therefore, the overall effect of a closed-loop supply chain is positive and significant.
Ključne besede: closed-loop supply chain, petrochemicals, cost effectivity, product stewardship, multiple regression analysis, factor analysis, sustainability
Objavljeno v DKUM: 12.12.2024; Ogledov: 0; Prenosov: 4
Celotno besedilo (1,60 MB)
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Opis: In this paper, a comparative analysis of the effects of groundwater, seepage and hydraulic heave on the optimal design of embedded retaining walls is carried out. The optimization model for an optimal retaining wall (ORW) minimizes the total length of the retaining wall considering design constraints. The model is extended to include the probability of failure as an additional constraint. This overcomes the limitations of the partial safety factor approach, which does not fully account for uncertainties in the soil. In contrast, the reliability-based design (RBD) approach integrates these uncertainties and enables an assessment of the impact of seepage and hydraulic heave on the reliability of the structure. A real-coded genetic algorithm was used to determine optimal designs for both optimization methods. The results of the case study show that the addition of seepage (groundwater flow) to the hydrostatic conditions has a modest effect on the embedment depth. The design based on partial safety factors, which takes seepage into account, leads to a slight increase in the embedment depth of 0.94% compared to a retaining wall design that only takes the hydrostatic conditions of the groundwater into account. When designing on the basis of probability failure, the percentage increase in embedment depth due to seepage is between 2.19% and 6.41%, depending on the target probability of failure. Furthermore, the hydraulic heave failure mechanism did not increase the required embedment depth of the retaining wall, which means that the failure mechanism of rotation near the base was decisive for the design.
Ključne besede: embedded retaining wall, reliability-based design, partial safety factor design, optimization, genetic algorithm
Objavljeno v DKUM: 10.12.2024; Ogledov: 0; Prenosov: 11
Celotno besedilo (2,13 MB)
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Opis: In a typical pressurized water reactor, neutron detectors located outside the reactor core monitor reactor power. In addition, they are also used to measure the reactivity of the control rods. A novel approach to calculate the ex-core neutron detector response in a typical pressurized water reactor using the Monte Carlo technique is presented. A detailed ex-core model of the Krško nuclear power plant was developed using the Monte Carlo neutron transport code MCNP. Due to the location of the ex-core neutron detectors, the hybrid code ADVANTG is used to generate variance reduction parameters to accelerte the convergence of the results outside the reactor core. To use ADVANTG, the fixed neutron source had to be reconstructed from the criticality core calculation. This paper presents the sensitivity analysis of the response of the ex-core detectors to the neutron data libraries used, the description of the fixed neutron source and the ADVANTG parameters. It was found that a pin-wise description of the neutron source for at least two rows of fuel assemblies at the core periphery is necessary for accurate results. Our results show the importance of a correct description of the prompt neutron spectra in the high energy region and the impact this has on the response of the ex-core detectors. The method in which the prompt neutron fission spectra for important fission nuclides are weighted by the calculated reaction rates has been shown to be the best approximation, with deviations from the reference calculation within statistical uncertainty. The effect of nuclear data libraries on the response of the ex-core detector was investigated, and the difference between the ENDF/B-VII.0 and the ENDF/B-VIII.0 nuclear data libraries was ∼11%. When the deficient evaluation of the 56Fe isotope included in the ENDF/B-VIII.0 nuclear data library was replaced by the improved evaluation from the IAEA INDEN project, the differences decreased to ∼3.7%. In addition, neutron flux redistributions due to control rod movement were investigated and flux redistribution factors were updated using Monte Carlo particle transport methods. The reaction rate redistribution factors obtained with methods presented in this paper are within 1% agreement with the currently used factors.
Ključne besede: MCNP, ADVANTG, pressurized water reactor, Monte Carlo neutron transport, control rod, neutron flux redistribution factor, rod insertion, krško nuclear power plant
Objavljeno v DKUM: 29.11.2024; Ogledov: 0; Prenosov: 7
Celotno besedilo (63,82 MB)
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Opis: The structure of a continuous-grid chiral cubic phase made of achiral constituent molecules is a hot topic in the field of thermotropic liquid crystals. Several structural models have been proposed so far. Resonant X-ray scattering (RXS), which gives information on the molecular orientation in the unit cell, could be applied to select the most appropriate model. We modeled the RXS response for the recently proposed chiral cubic phase structure with an all-hexagon chiral continuous grid. A tensor form factor of a unit cell is constructed, which enables calculation of intensities of peaks for all Miller indices. We find that all the symmetry allowed peaks are resonantly enhanced, and their intensity is much stronger than the intensity of the symmetry forbidden (resonant) peaks. In particular, we predict that a strong resonant enhancement of the symmetry allowed peaks (011) and (002), not observed in a nonresonant scattering, could be observed by RXS at the carbon absorption edge. By RXS at the sulfur absorption edge, one might observe a resonant peak (113) and resonantly enhanced peak (233), and resonant enhancement of all the peaks that are observed in a nonresonant scattering, which probably hide the rest of the predicted resonant peaks.
Ključne besede: chiral cubic phase, resonant X-ray scattering, theoretical modeling, tensor form factor
Objavljeno v DKUM: 14.08.2024; Ogledov: 100; Prenosov: 11
Celotno besedilo (2,18 MB)
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Opis: Events are one of the main factors of tourism development of a destination. Also, local events are one of the biggest factors that influence tourism in every town, city or community, and they are of great importance for a tourist destination. Summer in Samobor is a particularly successful new event that is in the process of development. In the theoretical part of the graduate thesis, the following topics are explained: the significance of the event, the type and size of the event, the planning and realisation of the event and the sustainability of the event. In the first part of our research, we presented the theoretical knowledge on the subject. Then we presented the event Summer in Samobor taking into account the following factors: aims and visions of the event, programme of the event, place and time of the event, registrations and permits, financial management, sponsors, media and promotion, food and beverages, and finally the sustainability of the event. As part of our research, we conducted interviews with the representative of the external agency Wanderlust Events and the representative of the Samobor Tourist Board. Using the interviews mentioned, we found out how the event developed, what factors influenced the success of the event and how sustainable the event is. The results of this research show that this event is developing every year and that the quality of the event is constantly being raised. Also, as some of the main success factors of the event Summer in Samobor, the following were emphasized: improvement of socio-cultural awareness, strong promotion of sustainable events, rich and high-quality content,uniqueness, cooperation and support of partners, good organization and creative ideas.
Ključne besede: event management, local event, sustainability, Samobor, factor of successful development
Objavljeno v DKUM: 23.02.2024; Ogledov: 416; Prenosov: 55
Celotno besedilo (2,26 MB)