Iskanje po katalogu digitalne knjižnice

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: 4
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Ključne besede: inter-machine reliability, knee extensors, knee flexors, angle of peak torque, peak torque
Objavljeno v DKUM: 23.01.2023; Ogledov: 650; Prenosov: 16
Celotno besedilo (1,43 MB)
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Opis: The master’s thesis discusses different approaches how to assure the quality and reliability of high voltage contactors in automotive industry. In the beginning, the history of the development is described, followed by basic knowledge about materials and magnetic theory used in relays. The main part of the thesis is tests defying to qualify the relays for usage in automotive industry. There are different tests, divided in different groups. Second important part is reliability prediction according to standards used in this area of business. Reliability prediction and calculation of failure rate on different contactors are described in last chapters. Calculation also included influence of different factors on life span of the parts. In conclusion, the results are commented and proposal for development is given based on results of the research.
Ključne besede: Automotive industry, high voltage contactors, testing, reliability, failure rate
Objavljeno v DKUM: 07.02.2018; Ogledov: 1592; Prenosov: 131
Celotno besedilo (1,89 MB)

Opis: The purpose of the study was to assess internal consistency by calculating coefficient alpha. It presents the variation in coefficient alpha, depending on questionnaire length and the homogeneity or heterogeneity of the questionnaire. The maximum possible value for coefficient alpha was also calculated by the item elimination method. The study included 99 children aged 10. The children completed The Athletic Coping Skills Inventory - 28 (ACSI-28; Smith et al., 1995), which contains seven constructs: coping with adversity, coachability, concentration, confidence and achievement motivation, goal setting and mental preparation, peaking under pressure and freedom from worry. The results confirmed that the values of the alpha coefficient vary depending on the number and composition of items and the sample size. In terms of item structure, homogeneous constructs yielded lower values for the alpha coefficient (in a range from .48 to .61) than the questionnaire with all the constructs (alpha = .79), despite higher inter-item correlations. In terms of the number of items, the longer test generated higher alpha coefficients (alpha= .79) than the shorter test (half-sets of items = .60, .73, .69, .70). A higher overall value (alpha= .83) can be achieved by item elimination.
Ključne besede: coefficient alpha, internal consistency, reliability
Objavljeno v DKUM: 20.09.2017; Ogledov: 1040; Prenosov: 122
Celotno besedilo (145,71 KB)
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Opis: This paper examines the reliability of the operation of cableway systems in Slovenia, which has major impact on the quality of service in the mountain tourism, mainly in wintertime. Different types of cableway installations in Slovenia were captured in a sample and fault tree analysis (FTA) was made on the basis of the obtained data. The paper presents the results of the analysis. With these results it is possible to determine the probability of faults of different types of cableways, which types of faults have the greatest impact on the termination of operation, which components of cableways fail most, what is the impact of age of cableways on the occurrence of the faults. Finally, an attempt was made to find if occurrence of faults on individual cableway installation has also impact on traffic on this cableway due to reduced quality of service.
Ključne besede: service quality, reliability, fault tree analysis, faults, quality, ski-tows, chairlifts, aerial ropeways, cableways
Objavljeno v DKUM: 05.06.2017; Ogledov: 1761; Prenosov: 505
Celotno besedilo (653,93 KB)
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