Early systems engineering and requirements definition requires quantitative information about potential solutions prior to having sufficient information or time to develop detailed models. This research develops and demonstrates a transparent and repeatable process for rapidly creating quantitative models that leverage existing expert knowledge. This process is built upon established modeling frameworks and current literature for low fidelity modeling and hierarchical expert-based methods. The process includes system definition using interactive morphological analysis and gathering information from subject-matter experts with computer-based interfaces in order to create a series of linear performance models. Available volunteers provided data for a relevant aerospace design to test the process as a whole and several hypotheses about specific methodological decisions made during the development. The collected data was analyzed for similarity among participants and for similarity to model parameters of an existing trusted truth model. The results of the analysis demonstrated the ability for expert-based models to accurately match the behavior of the truth models and of historical data.

In the modem automotive industry product times to market are being increasingly compressed. In the earthmoving and construction machine industry this is also true with the manufacturer having to respond to new customer requirements quickly and decisively. Virtual prototyping is a vital tool in the vehicle engineer's armoury, allowing a large portion of developmental investigation to be done on the virtual model with the attendant savings in time and cost and allowing often dangerous manoeuvres to be predicted and investigated prior to actual physical prototype testing. The University of Natal BELL Equipment collaborative effort involves the vehicle dynamics modelling and model validation of a BELL Equipment manufactured B40C Articulated Dump Truck (ADT). The modelling was completed using the multibody system (MBS) simulation software package, ADAMS. Initial modelling and simulation results are presented with specific attention paid to the introduction of valid data for compliant joints in the MBS as well as modelling of the tire. The physical testing of the ADT is also presented as well as a discussion of the data acquisition system. Key results from the physical testing of the ADT are also presented and discussed. / Thesis (M.Sc.Eng.)-University of Natal,Durban, 2003.

O emprego de sistemas passivos de condicionamento de ambientes ao invés de equipamentos de climatização artificial pode ser uma solução bastante conveniente para diminuir o gasto de eletricidade e melhorar o conforto térmico de uma edificação. Uma das técnicas usadas para a melhoria do desempenho térmico de edificações é a utilização de “Paredes Trombe”. Este é um sistema de climatização passiva que utiliza ganhos solares associados à inércia térmica de uma parede para absorver calor no período frio sem bloquear suas perdas do período quente. Esta pesquisa tem como objetivo analisar o potencial de aquecimento/resfriamento de um sistema de climatização passiva baseado na utilização de uma Parede Trombe. Para isso, foram construídos dois protótipos em escala reduzida, sendo um deles com Parede Trombe e o outro em alvenaria de blocos de concreto, sem o sistema passivo. As medições ocorreram em períodos frios (datas) de 2011 e no período de verão de 2012, para configurações distintas da Parede Trombe. Os resultados mostraram que a Parede Trombe teve um resultado positivo tanto para o inverno quanto para o verão. / The use of passive solar heating for achieving thermal comfort inside a building is a very convenient solution to reduce the cost of electricity. One of the techniques used to improve the thermal performance of buildings is using "Trombe Walls." This is a passive solar heating system that uses solar gains associated with the thermal inertia of a wall to absorb heat during cold periods without blocking their loss in the warm period. This research aims to analyze the potential for heating and cooling of a Trombe Wall. For this, two cells were built on a small scale: passive solar cell and a reference cell. The measurements took place in cold periods (dates), of 2011 and during the summer of 2012, for different configurations of the Trombe Wall. The results showed that the Trombe Wall had a positive result for both winter and summer.

M.Tech (Department of Electronic Engineering, Faculty of Engineering and Technology), Vaal University of Technology / In the world of research and development, the ability to rapidly manufacture a prototype or part has become a significant part of the manufacturing process. This requirement has given rise to some unique manufacturing technologies. One of these technologies is Additive Manufacturing (AM), or also more commonly known as 3D printing. There are several AM technologies available and can be divided into three major AM categories namely: liquid, powder and solid sheet based. For this research study, the primary focus will be on powder-based technologies. Powder-based technologies make use of materials in powder form and use different fusion techniques to fuse the powder particles together. All the powder bed fusion technologies consist of the same basic components, namely a powder chamber, build chamber, re-coater and a powder fusion system. For each layer of the build, the re-coater applies a new layer of powder from the powder chamber to the build chamber, and then the specific type of powder fusion system will fuse the powder particles together. This process will then be repeated until the entire build has completed. Currently, powder bed fusion AM platforms do not have re-coating quality feedback into the printing system. Thus, when errors or defects occur on the powder bed surface during the re-coating process, they can affect the structural integrity of the parts. Parts must then be reprinted, which becomes costly due to wasted raw materials, electricity and time. Raw material and sundry wastage was some of the key factors that reduces the overall efficiency of the identified AM technology. Due to the increased problem with wasted materials, the need arose to develop a re-coater monitoring system, which could be used to increase the overall efficiency of a powder-based system. For the development of a re-coater monitoring system, a review of three different types of monitoring technologies such as computer vision, laser scanning and a time-offlight camera was conducted. Based upon the relatively low cost, low computer resource requirements and high accuracy, computer vision was considered as the best suited technology for development of the monitoring system. To select the correct camera to capture images of the powder bed, the required specifications for the camera, lens and mounting position were determined mathematically. A software program was then developed to autonomously detect re-coating errors on the captured image after each re-coating cycle using image processing techniques. Each of the captured powder bed images were divided into 16 equal sized quadrants, where each quadrant was processed individually. Each of the quadrants was examined using an edge detection algorithm to detect any changes in contrast that would indicate a defect or re-coating error. The probability of a possible re-coating error or defect was calculated for each quadrant and displayed as a percentage value. The active re-coater monitoring system was also integrated into the Voxeljet VX500 to validate the system’s operation. The system was used to monitor a total of seven build jobs on the Voxeljet VX500. However, the first three build jobs could not be successfully monitored as some parameters of the system had to be re-adjusted to ensure proper operation. The last four build jobs were monitored successfully and recorded results that proved that the active re-coater monitoring system could indeed detect defects and re-coating errors when they occurred.

Thesis (M. Tech. (Design and Studio Art)) -- Central University of Technology, Free State, 2014 / This quantitative research project investigates the utilization of emerging technologies within the arts with a view on establishing an interdisciplinary approach between ceramics and engineering. The traditional manufacturing method of producing master moulds is a time-consuming process for the studio ceramicist. This study explores whether computer-aided design (CAD) and computer numerical control (CNC) milling can accelerate the design and manufacturing process when developing master moulds as an alternative to using traditional methods. It investigates whether SolidWorks® can be applied as a suitable CAD design tool for the creation of ceramic vessel forms in order to reduce the design development time frame. It furthermore investigates whether CNC milling can be used as a viable manufacturing technology for the making of vessel prototypes and master moulds from CAD data, the overall objective being to improve and accelerate the plaster of Paris master mould manufacturing process for the batch production of studio-based ceramic artefacts. Findings from this study indicate that emerging technologies have a lot to offer the artist when it comes to providing new possibilities for the creation of artefacts and that SolidWorks® and CNC milling can be utilized as a viable interdisciplinary manufacturing approach between ceramics and digital manufacturing technologies.

CNPq / Este trabalho apresenta um retificador trifásico isolado com correção do fator de potência utilizando um autotransformador Scott e utilizando dois retificadores monofásicos isolados com correção do fator de potência de estágio único (S2). O autotransformador Scott faz uma redução de fases permitindo que se utilizem dois retificadores de estágio único. Os conversores monofásicos utilizados são do tipo Full-Bridge Flyback. O conversor proposto pode operar como elevador ou abaixador de tensão dependendo da relação entre as tensões de entrada e saída do conversor. O controle do conversor foi feito via MCU modelo TMS320F28335. Este trabalho apresenta a análise teórica do conversor operando em modo de condução contínua (CCM), bem como os resultados experimentais baseado em um protótipode 4kw. / This work presents a three-phase isolated rectifier with power factor correction using a Scott autotransformer and two isolated single-phase single-stage (S2) rectifiers. The Scott autotransformer provides a phase reduction allowing the use of two single-phase rectifiers. The single-phase converters used are the Full-Bridge Flyback type. The proposed converter can operate as a step-down or a step-up voltage, according to the relation between input andoutput voltage. The control of the converter was made in a MCU model TMS320F28335. This paper presents the theoretical analysis of the converter for continuous conduction mode (CCM) as well as experimental results based on a 4 kW prototype.