This research details the development of a large-scale, computer vision-based touch screen capable of supporting a large number of simultaneous hand interactions. The system features a novel lightweight multi-point tracking algorithm to improve real-time responsiveness. This system was trialled for six months in an exhibition installation at World Expo 2005 in Aichi, Japan, providing a robust, fault-tolerant interface. A pilot study was then conducted to directly compare the system against other, more established input methods (a single-touch case, a two-mouse case and a physical prototype) to determine the effectiveness and affordances of the multi-touch technology for arranging information on a large-scale wall space in a paired collaborative task. To assist in this study, a separate visualisation and interaction classification tool was developed, allowing the replay of XML log data in real time to assist in the video analysis required for observation and hypothesis testing.

The credit card industry is huge with over two and a half billion cards shipped annually. A local card manufacturer, with a production volume in excess of forty million cards annually, approached the University of Canterbury to design and develop advanced card manufacturing technology. The motivation behind this development was the desire of the sponsoring company to keep abreast of new technologies and to have the ability to manufacture and supply cards with this new and emerging technology into a highly competitive world market. This thesis reports the research surrounding the development of a dedicated new machine tool explicitly designed to implement the emerging technologies found in the international credit card industry. The machine tool, a dedicated milling machine, was not developed in its entirety within these pages; however, three major constituents of the machine were researched and developed to a point where they could be implemented or become the subject of further research. The three areas of interest were; • A machine table system that avoided the increased zonal wear to which linear bearings are subject, typically due to short high frequency traversals, and also the high friction and mass generally found in dovetail slides. • Design requirements demanded the use of a single commercially available carbide cutter to produce 1500 components per hour. Therefore, a purpose built high (revs per minute) rpm spindle and drive system specifically for use with polymeric materials, (R-PVC in particular) was deemed necessary. • Tracking the cutter depth in relation to an RFID aerial track embedded within the credit card core. The aerial tracking was to be dynamic and occur during the machining process with the machine “remembering” the depth of cut at contact with the aerial. Each of the three areas was researched via an in-depth literature review to determine what and if any material had been published in these fields. For the development of the machine table a novel flexure hinge idea was considered. Considerable material was discovered about flexures, but very little was found to be relevant to the application of high displacement metal flexures necessary to meet the required levels of table movement. In effect the proposed machine table system and research in this field would be novel. The high performance spindle investigation became directed into a much narrower focus as it progressed; that of determining the power consumption required to machine the integrated circuit pockets in an R-PVC work piece. This was due to the lack of information pertaining to the physical properties of polymeric materials, in particular the specific cutting pressure. The depth following sensor array was configured using capacitance detection methods to determine the distance between the cutter?s end and the aerial tracks. Capacitance sensing methods, whilst not new, were developed into a novel arrangement to meet the specific cutter tracking requirements of the proposed new machine tool. Each of the respective development areas had concept designs completed and were prototyped before being tested to determine the effectiveness of the respective designs. The outcomes from the testing are reported herein, and show each constituent part to be basically feasible, in the application. The results were sufficient to indicate that each development showed distinct potential but further development and integration into the machine tool should ensue.

In recent years, there has been a substantial growth in the application of carbon fiber reinforced plastic (CFRP) composite materials in automobile and aerospace industries due to their superior properties such as lightweight, high strength, excellent corrosion resistance, and minimal fatigue concerns. The present study evaluates the drilling performance of woven carbon fiber reinforced plastics under both dry and cryogenic cooling conditions using uncoated solid carbide drill with a through-hole for coolant application. The effects of the cooling conditions and the cutting parameters on drilling performance in drilling CFRP were evaluated in terms of generated thrust force, torque, cutting edge radius, outer corner flank wear, hole quality (including surface roughness, diameter error, roundness, delamination, burr formation, sub-surface quality). Both cooling conditions and cutting parameters were found to influence the thrust force and torque at different levels. The thrust force and the torque are higher in cryogenic cooling under all cutting parameters. In most of the cases, cryogenic drilling gives better bore-hole quality with lower surface roughness, more accurate diameter, less burr generation, better sub-surface quality, etc. Also, the tool-wear rates measured in drilling shows that cryogenic drilling produces less tool-wear than dry drilling does.

Lameness and mastitis are the two most costly diseases in the dairy industry. Reduction of these diseases through housing and management is beneficial. Compost bedded pack (CBP) and sand freestall barns were compared in a long-term, on-farm study to assess the effect of housing on each disease. Another research objective was to evaluate the effects of ambient weather conditions on moisture and 20 cm internal temperature of CBP. Compost bedded pack moisture, C:N ratio, and internal temperature effects on cleanliness, mastitis, and bedding bacterial counts were also considered. The last research objective was to evaluate the economics of bedding material decisions in CBP and provide a user-friendly decision support tool to predict bedding costs and usefulness.

Application of mechanical micromachining for fabricating complex three-dimensional (3D) micro-scale features and small parts on a broad range of materials has increased significantly in the recent years. In particular, mechanical micromachining finds applications in manufacturing of biomedical devices, tribological surfaces, energy storage/conversion systems, and aerospace components. Effectively addressing the dual requirements for high accuracy and high throughput for micromachining applications necessitates understanding and controlling of dynamic behavior of micromachining system, including positioning stage, spindle, and the (micro-) tool, as well as their coupling with the mechanics of the material removal process. The dynamic behavior of the tool-collet-spindle-machine assembly, as reflected at the cutting edges of a micro-tool, often determines the achievable process productivity and quality. However, the common modeling techniques (such as beam based approaches) used in macro-scale to model the dynamics of cutting tools, cannot be used to accurately and efficiently in micro-scale case. Furthermore, classical modal testing techniques poses significant challenges in terms of excitation and measurement requirements, and thus, new experimental techniques are needed to determine the speed-dependent modal characteristics of miniature ultra-high-speed (UHS) spindles that are used during micromachining. The overarching objective of this thesis is to address the aforementioned issues by developing new modeling and experimental techniques to accurately predict and analyze the dynamics of micro-scale cutting tools and miniature ultra-high-speed spindles, including rotational effects arising from the ultra high rotational speeds utilized during micromachining, which are central to understanding the process stability. Accurate prediction of the dynamics of micromachining requires (1) accurate and numerically-efficient analytical approach to model the rotational dynamics of realistic micro-tool geometries that will capture non-symmetric bending and coupled torsional/axial dynamics including the rotational/ gyroscopic effects; and (2) new experimental approaches to accurately determine the speed-dependent dynamics of ultra-high-speed spindles. The dynamic models of cutting tools and ultra-high-speed spindles developed in this work can be coupled together with a mechanistic micromachining model to investigate the process stability of mechanical micromachining. To achieve the overarching research objective,first, a new three-dimensional spectral- Tchebychev approach is developed to accurately and efficiently predict the dynamics of (micro) cutting tools. In modeling the cutting tools, considering the efficiently and accuracy of the solution, a unified modeling approach is used. In this approach, the shank/taper/extension sections, vibrational behavior of which exhibit no coupling between different textural motion, of the cutting tools are modeled using one-dimensional (1D) spectral-Tchebychev (ST) approach; whereas the fluted section (that exhibits coupled vibrational behavior) is modeled using the developed 3D-ST approach. To obtain the dynamic model for the entire cutting tool, a component mode synthesis approach is used to `assemble' the dynamic models. Due to the high rotational speeds needed to attain high material removal rate while using micro tools, the gyroscopic/rotational effects should be included in predicting the dynamic response at any position along the cutting edges of a micro-tool during its operation. Thus, as a second step, the developed solution approach is improved to include the effects arising from the high rotational speeds. The convergence, accuracy, and efficiency of the presented solution technique is investigated through several case studies. It is shown that the presented modeling approach enables high-fidelity dynamic models for (micro-scale) cutting-tools. Third, to accurately model the dynamics of miniature UHS spindles, that critically affect the tool-tip motions, a new experimental (modal testing) methodology is developed. To address the deficiency of traditional dynamic excitation techniques in providing the required bandwidth, repeatability, and impact force magnitudes for accurately capturing the dynamics of rotating UHS spindles, a new impact excitation system (IES) is designed and constructed. The developed system enables repeatable and high-bandwidth modal testing of (miniature and compliant) structures, while controlling the applied impact forces on the structure. Having developed the IES, and established the experimental methodology, the speed-dependent dynamics of an air bearing miniature spindle is characterized. Finally, to show the broad impact of the develop modeling approach, a macro-scale endmill is modeled using the presented modeling technique and coupled to the dynamics of a (macro-scale) spindle, that is obtained experimentally, to predict the tool-point dynamics. Specific contributions of this thesis research include: (1) a new 3D modeling approach that can accurately and efficiently capture the dynamics of pretwisted structures including gyroscopic effects, (2) a novel IES for repeatable, high-bandwidth modal testing of miniature and compliant structures, (3) an experimental methodology to characterize and understand the (speed-dependent) dynamics of miniature UHS spindles.

This study examines the effect fallback foods, foods eaten when other, more preferred foods are scarce, have on the tool-using behaviors of capuchin monkeys. In the arid Serra da Capivara National Park in Brazil, black-striped capuchins (Cebus libidinosus) use stone tools to dig for underground tubers, a very rare behavior among primates. I test the hypothesis that the capuchins in the Serra da Capivara exploit tubers as a fallback food because palm nuts, an important fallback resource to other groups of capuchins living in arid environments, are either rare or absent there. Studies of floristic analysis at the park and other capuchin sites show that palm nut species recorded to be consumed by capuchins are not found at the Serra da Capivara. Additionally, nutritional analysis of both palms nuts and tubers suggest that tubers could act as a replacement for palm nuts as a fallback food. This may have relevance to human evolution, as several researchers suggest tubers and other underground storage organs were important resources to early hominins. / Department of Anthropology

In sheet metal forming operations the life length of the production equipment islargely dependent on the wear of the tools that are in direct contact with the sheet.One form of adhesive wear where some sheet material gets transferred to the tool, alsoknown as galling, is the most common cause of tool failure. The transferred materialsticks firmly to the tool and will scratch subsequent sheets and increase friction, renderingthem anywhere from aesthetically unsightly to completely ripped apart. Withcareful combination of several parameters the tools production life can be significantlyextended. The surface preparation of the tools has a large influence on the tool life, thesurface has to be smooth and yet not without texture. It was shown in strip reductiontesting that the orientation as well as the depth of the surface texture left by polishinginfluenced the tool life and that a texture perpendicular to the sliding direction was toprefer. The geometry of the forming tool is also a parameter to take into account as itinfluences the tool life not only by changing the contact pressure but also in itself. Ina sliding against flat sheet test rig a lower contact pressure increased the sliding distanceto galling. When two different geometries were compared at the same contactpressure it was found that there was a difference in tool life. As to the tool itself thematerial it’s made of influences the wear rate and tool life. Different tool steels wasinvestigated in sliding wear against metal sheets; Vancron 40 performed better thanVanadis 6 and S290PM performed better than a AISI M2 grade steel.

The use of models for designing and developing Information Systems (IS) has changed in recent years. Models are no longer considered a peripheral documentation medium that is poorly maintained and often neglected. Rather, models are increasingly seen as essential parts of the final product—as central artifacts that drive and guide the development efforts. The knowledge that modelers rely on when designing models is represented as formal models and clearly defined rules for transforming the models. The flexibility, reliability, and effectiveness offered by the formal models and the transformations are making Model Driven Development (MDD) a popular choice for building IS. Models also serve in describing enterprise design, where enterprise-level models capture organizational knowledge and aid in understanding, improving, and growing the enterprise. Enterprise Modeling (EM) offers a structured and unified view of the enterprise, thereby enabling more informed and accurate decisions to be made. Many MDD approaches have been proposed to tackle a wide range of IS-related issues, but little attention is being paid to the source of the knowledge captured by the IS models. EM approaches capture organizational knowledge and provide the necessary input and underlying context for designing IS. However, the results produced by EM approaches need to be manually analyzed by modelers to create the initial MDD model. This interruption of the MDD process represents a gap between enterprise models and MDD models. Limited research has been done to connect EM to MDD in a systematic and structured manner based on the principles of model-driven development. This thesis proposes a unifying meta-model for integrating EM and MDD. The meta-model captures the inherent links that exist between organizational knowledge and IS design. This helps to improve the alignment between organizational goals and the IS that are created to support them. The research presented herein follows the guidelines of the design science research methodology. It starts with a state-of-the-art survey of the current relationship between MDD and prior stages of development. The findings of the survey are used to elicit a set of necessary properties for integrating EM and MDD. The unifying meta-model is then proposed as the basis for an integrated IS development approach that applies the principles of MDD and starts on the enterprise level by considering enterprise models in the development process. The design of the meta-model supports the elicited integration properties. The unifying meta-model is based on the Enterprise Knowledge Development (EKD) approach to EM. A prototype tool is developed to support the unifying meta-model, following a study to choose a suitable implementation environment. The use of the unifying meta-model is demonstrated through the implemented tool platform using an example case study, revealing its advantages and highlighting the potential for improvement and future development.

Detta examensarbete har sitt fokus på förskolebarnens lek och dess olika former med handdockan. Syftet med denna studie var att undersöka hur barnen intregerar med handdockan och hur de använder dem som medierande redskap. Undersökningen var utförd som en observationsstudie av barnen på en förskola i åldern 3-5 år. De resultat som framkommit pekar på att en handdockas närvaro i barnens lek kan te sig på skilda sätt. Barns möte med handdockan kan både inspirerea, utmana och försvåra leken. De lekformer som synliggjorts i denna studie visade att imitation och transformation stod i centrum. En annan upptäckt som gjordes under studien var pojkars och flickors skilda sätt att leka med handdockorna. Handdockan kan fungera som ett redskap som kan återspegla tidigare händelser och i och med detta försökte barnen få en förståelse för det som de upplevt. En handdocka kan ge barnen vissa budskap som berikar deras lekar, deras utveckling och det livslånga lärandet. För dessa barn kunde handdockan tillsammans med barnens egna erfarenheter fungera som ett medierande redskap och guida dem till en förståelse av sin omvärld. Denna studie representerar även de barn som hade vissa svårigheter att ta till sig handdockor i leken. Kanske kunde detta bero på att handdockorna inte gav dem några associationer, vare sig i den faktiska eller fiktiva omvärlden.

According to the Department of Water Affairs (DWAF, 2004 p.15), South Africa’s water resources are scarce and extremely limited and much of this precious resource is utilised and consumed in our industries. Treatment and re-use of effluent generated is, in some cases, preferred over use of alternate water resources (Du Plessis, 2008 p.3). The volume of effluent generated in treatment processes like ultra-filtration (UF) and reverse osmosis (RO) units is determined by the feed water quality, with high water loss through effluent generation at poor feed water quality. Current UF and RO applications require an increased UF production capacity due to the use of UF filtrate for periodic backwashing of the UF membrane units. This results in loss of water and decreases overall recovery. The need therefore exists to increase the overall recovery of product water from the raw water stream by reducing the amount of effluent generated. This would be possible to achieve by using RO brine to backwash the UF unit. The study was conducted to provide a modelling tool, assisting management to optimise the use of RO brine as backwash water on the UF system at the Medupi power station. The secondary objective of this study was the development of a modelling tool that can be used for other projects, new or existing, as a measure and indication of the usability of RO brine as backwash water on UF systems. By successfully applying this newly developed model, the viability of utilising the RO brine as backwash water for the UF was investigated. This modification would lead to utilizing smaller UF units than previously envisioned, which in turn leads to reducing capital cost with 11.07% and operating expenditure with 9.98% at the Medupi power station. This also has a positive environmental impact by reducing the amount of raw water used monthly by 10.34% (108 000 m3/month). / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2014