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Transmissions are an essential part of a vehicle powertrain. An optimally designed powertrain can result in energy savings, reduced environmental impact and increased comfort and reliability. Along with other components of the powertrain, efficiency is also a major concern in the design of transmissions. The churning power losses associated with the motion of gears through the oil represent a significant portion of the total power losses in a transmission and therefore need to be estimated. A lack of reliable empirical models for the prediction of these losses has led to the emergence of CFD (Computational Fluid Dynamics) as a means to (i) predict these losses and (ii) promote a deeper understanding of the physical phenomena responsible for theselosses in order to improve existing models. The commercial CFD solver STAR-CCM+ is used to investigate the oil distribution and the churning power losses inside two gearbox configurations namely an FZG (Technical Institute for the Study of Gears and Drive Mechanisms) gearbox and a planetary gearbox. A comparison of two motion handling techniques in STARCCM+ namely MRF (Moving Reference Frame) and RBM (Rigid Body Motion) models is made in terms of the accuracy of results and the computational requirements using the FZG gearbox. A sensitivity analysis on how the size of gap between the meshing gear teeth affects the flow and the computational requirements is also done using the FZG gearbox. Different modelling alternatives are investigated for the planetary gearbox and the best choices have been determined. The numerical simulations are solved in an unsteady framework where the VOF (Volume Of Fluid) multiphase model is used to track the interface between the immiscible phases. The overset meshing technique has been used to reconfigure the mesh at each time step. The results from the CFD simulations are presented and discussed in terms of the modelling choices made and their effect on the accuracy of the results. The MRF method is a cheaper alternative compared to the RBM model however, the former model does not accurately simulate the transient start-up and instead provides just a regime solution of the unsteady problem. As expected, the accuracy of the results suffers from having a large gap between the meshing gear teeth. The use of compressible ideal gas model for the air phase with a pressure boundary condition gives the optimum performance for the planetary gearbox. The outcomes can be used toeffectively study transmission flows using CFD and thereby improve the design of future transmissions for improved efficiency.

Magister Legum - LLM / South Africa

Práca sa zaoberá spojeniami medzi štatistickou fyzikou a strojovým učením s dôrazom na základné princípy a ich dôsledky. Ďalej sa venuje obecným vlastnostiam spektroskopických dát a ich zohľadnení pri pokročilom spracovaní dát. Začiatok práce je venovaný odvodeniu partičnej sumy štatistického systému a štúdiu Isingovho modelu pomocou "mean field" prístupu. Následne, popri základnom úvode do strojového učenia, je ukázaná ekvivalencia medzi Isingovým modelom a Hopfieldovou sieťou - modelom strojového učenia. Na konci teoretickej časti je z Hopfieldovej siete odvodený model Restricted Boltzmann Machine (RBM). Vhodnosť použitia RBM na spracovanie spektroskopických dát je diskutovaná a preukázaná na znížení dimenzie týchto dát. Výsledky sú porovnané s bežne používanou Metódou Hlavných Komponent (PCA), spolu so zhodnotením prístupu a možnosťami ďalšieho zlepšovania.

Introduction of this thesis is dedicated to the description of basic concepts and algorithms for image processing using sparse representation. Furthermore there is mentioned neural network model called Restricted Boltzmann machine, which is in the practical part of the thesis subject of behaving observation in the task of determining the optimal block size for extrapolation using K-SVD algorithm

Syftet med denna studie var att belysa svenska frivårdsinspektörers erfarenheter av att använda RBM-modellen. Vi har genomfört en kvalitativ intervjustudie med sex frivårdsinspektörer. Frivårdsinspektörerna uppvisade en positiv inställning till användandet av RBM-modellen. De uppvisade även erfarenheter av att det finns brister och svårigheter i användningen av modellen och kopplade detta till riskbedömningsinstrument och klienternas egenheter. De positiva inslag som användningen av modellen har tillfört är en struktur, tydlighet och fokus i arbetet samt att frivårdsinspektörerna lyfte RBM-modellens relativa övertag mot tidigare arbetssätt. Det framkom även i studien skilda uppfattningar rörande RBM-modellens mottaglighetsprincip. Frivårdsinspektörernas olika syn på detta område var något som kunde tänkas påverka deras användning av principen. De brister som kopplades till användningen bestod av flera möjliga faktorer. En av dessa var den grundutbildning rörande modellen som ges inom Kriminalvården. Utbildningen kan vara en förklarande faktor till de svårigheter frivårdsinspektörerna identifierade i sitt arbete med RBM-modellens mottaglighetsprincip. / The purpose of this study was to examine and illustrate Swedish probation officers’ experiences of their use of the RNR model. We have completed six qualitative interviews with probation officers. The probation officers showed a positive attitude towards the RNR model. They also showed experiences of flaws and difficulties in their use of the model and related these to the risk assessment instrument and the characteristics of the clients. The positive effects that the use of the RNR model had was that it brought structure, lucidity and focus to their work. They also pointed out the models relative advantage towards earlier methods. It was also clear that the probation officers had different views of the responsivity principle. These different views could affect their use of this principle. The difficulties regarding the use of the model that could be related to the probation officers’ experiences consisted of several possible causes. Education regarding the model was one of these possible causes that we found could explain the experienced difficulties in the probation officers use of the RNR model.

In this study, the goal is to optimize the process and to reduce the clogging tendency during the continuous casting process. The focus is on clogging when the refractory base material (RBM) in the SEN is in contact with the liquid steel. It is difficult or impossible to avoid non-metallic inclusions in the liquid steel, but by a selection of a good RBM in the SEN clogging can be reduced.   Different process steps were evaluated during the casting process in order to reduce the clogging tendency. First, the preheating of the SEN was studied. The results showed that the SEN can be decarburized during the preheating process. In addition, decarburization of SEN causes a larger risk for clogging. Two types of plasma coatings were implemented to protect the RBM, to prevent reactions with the RBM, and to reduce the clogging tendency. Calcium titanate (CaTiO3) mixed with yttria stabilized zirconia (YSZ) plasma coatings were tested in laboratory and pilot plant trials, for casting of aluminium-killed low-carbon steels. For casting of cerium alloyed stainless steels, YSZ plasma coatings were tested in laboratory, pilot plant and industrial trials. The results showed that the clogging tendency was reduced when implementing both coating materials.   It is also of importance to produce clean steel in order to reduce clogging. Therefore, the steel cleanliness in the tundish was studied experimentally. The result showed that inclusions originated from the slag, deoxidation products and tundish refractory and that they were present in the tundish as well as in the final steel product. / VINNOVA

Magister Public Health - MPH / Over the years major changes have occurred in the focus, approach and application of monitoring and evaluation systems as a result of increased levels of emphasis towards achieving results (outcomes) as opposed to activities and outputs. As the focus of management changes from activities to results, so too has the focal point of M&E shifted from the traditional M&E system of progress monitoring that only deals with assessing inputs and implementation processes, to a results-based M&E system that emphasizes the need to assess the contributions of intervention to development outcomes. Nowadays funders, stakeholders and donor agencies want to see the difference that development initiatives make in the livelihood of project beneficiaries.Results-based M&E systems are essential components of most organisational structures responsible for development services and this is very fundamental as it provides vital information and empowers policy makers to take better informed decisions. The foundation of an M&E system is the very first step which is in essence called a ‘readiness assessment’. Such an assessment must be conducted before the actual establishment of an M&E system. Just as a building must begin with a foundation, constructing an M&E system must also begin with the establishment of a readiness assessment. Without this assessment and an understanding of the preparedness and commitment of the organisation, establishing an M&E system may be fraught with difficulties and failure.The Monitoring and Evaluation (M&E) of the Early Childhood Development (ECD) Programme of Ikamva Labantu has always been in the form of a reporting-type check list. The Centre is in a process of establishing an effective M&E system. The problem being investigated in this study is whether Ikamva Labantu has achieved a sufficient level of readiness to establish a results-based monitoring and evaluation system. However, the study shall also highlight crucial aspect of PM&E and RBM&E that will have to be taken into consideration with the establishment of the actual M&E system.With the use of the qualitative research method, the aim of this study is to analyse and assess the readiness assessment phase for establishing a monitoring and evaluation system in the Early Childhood Development (ECD) Programmes of Ikamva Labantu Centre, Khayelitsha.