To produce cast steel crankshafts, risering and gating systems are developed. Filling and solidification simulations of the steel crankshaft rigging are carried out to confirm that the rigging developed will produce a low porosity casting. A sand mold is created with Computer-aided design software, based on the developed crankshaft and rigging. Two prototype crankshafts are cast from the sand molds, and analyzed for porosity. The porosity analysis results are compared directly to the simulated porosity, and found to be in good agreement. From the analysis of the prototype crankshaft, rigging systems for a two-on and single-throw crankshaft are developed. A new casting method for steel is developed. The counter-gravity with pressurization during solidification casting method utilizes vacuum pressure of 7.3 psia to draw liquid steel into a mold, where it is held until the inlet has solidified. Once the inlet has solidified, the vacuum pressure is released, and the pressure of the entire system is raised to 45 psia. Exothermic hot topping keeps the top of the riser liquid while the rest of the casting forms a solid shell. Therefore, the pressure only acts on the liquid metal at the top of the riser, forcing the liquid metal to feed farther into the casting. The new method is tested with simple bar castings. Analysis of cast bars shows that centerline porosity is fed by the riser when pressurized, while the gravity-filled control casting is not.

The purpose of this mini-dissertation is to analyse and establish the potential money laundering and terrorism financing risks and implications of virtual currencies on the prevalent South African regulatory and supervisory architecture. The South African financial system is exceedingly regulated and supervised to ensure that it is prudent and reputable, and to enhance the safety and soundness thereof. Recently, technological innovations and developments have created immense issues especially from a financial regulatory and supervisory perspective. Financial technology has produced mysterious phenomena such as blockchain, insuretech, crowdfunding and virtual currencies. Presently, virtual currencies, which will be the focus of this study, do not fall within the ambits of the South African financial regulatory or supervisory regime and have thus created a regulatory arbitrage. This poses a significant number of risks and implications to the South African context, namely tax evasion; crossborder illicit flow of funds; contravention of exchange control regulations; financial instability; monetary policy uncertainty; inaccurate economic statistics; non-reporting of balance of payment requirements; and money laundering and terrorist financing (ML/TF). The study aims to construct a clear description and categorisation of virtual currencies within a South African context. Secondly, the study will set out the risks and implications that virtual currencies pose to the South African financial system from a ML/TF perspective. Finally, the study will present a possible solution to close the current regulatory arbitrage presented by virtual currencies in the South African financial sector. / Mini Dissertation (LLM)--University of Pretoria, 2019. / Mercantile Law / LLM Banking Law / Unrestricted

In the last decade, many attempts were made to put metal organic frameworks (MOFs) in industrial applications, but most of these efforts weren’t successfully. As one of the few MOFs produced on industrial scale, ZIF-8 has interesting pore size, huge internal surface area and great thermal and chemical stability. Therefore, ZIF-8 might become the first MOF, which will be applied in industrial separation processes. In this thesis, a synthesis study is presented, which leads to a cheap and convenient way to
fabricate defect-free and thin ZIF-8 membranes on porous polymeric supports showing high selectivity and high gas permeance. The ZIF-8 layers were produced via a contra-diffusion method. Several polymeric membranes were employed as support in this study, such as PAN, PEI, PSU, PA and PTSC. We studied the influence of the polymeric support properties for the ZIF-8 membrane preparation and optimized the ZIF-8 preparation conditions. The ZIF-8 membranes were characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). For gas permeation test, we chose a Wicke-Kallenbach apparatus to measure membrane’s gas permeance and selectivity. One of the best ZIF-8 membranes exhibited a hydrogen permeance of 3.45 × 10-8 mol m-2 s-1 Pa-1 and
an ideal selectivity of hydrogen over propane of about 500.

No description available.

The purpose of this study was to compare effects of the front squat and back squat on vertical jump and lower body power index of division 1 male volleyball players. Eighteen NCAA Division 1 male volleyball players volunteered for this study and were assigned either to a back squat or a front squat training program group. Subjects followed the training program for 8 weeks. Counter-movement vertical jump (CMVJ) height and lower body power index were measured at 0, 4 and 8 weeks of the study. A 2x3 factorial ANOVA revealed no significant difference in CMVJ height and power index between the training groups (p = 0.921). In addition, changes in power index over 8 weeks were not significant (p = 0.931). There was significant improvement for both groups in CMVJ height from 0 to 4 weeks (p = .001) and from 0 to 8 weeks (p = .000), but not from 4 to 8 weeks (p =.080). Both front squat and back squat strength training programs were both equally effective at enhancing CMVJ performance.

Drones are unmanned aerial vehicles (UAVs) operated remotely with the help of cameras, GPS, and on-device SD cards. These are used for many applications including civilian as well as military. On the other hand, drone swarms are a fleet of drones that work together to achieve a special goal through swarm intelligence approaches. These provide a lot of advantages such as better coverage, accuracy, increased safety, and improved flexibility when compared to a single drone. However, the deployment of such swarms in an adversarial environment poses significant challenges. This work provides an overview of the current state of research on drone swarms in adversarial environments including algorithms for swarming formation of robotic attack drones with their strengths and weaknesses as well as the attack strategies used by attackers. This work also outlines the common adversarial counter-attack methods to disrupt drone attacks consisting of detection and destruction of drone swarms along with their drawbacks, a counter UAV defense system, and splitting large-scale drones into unconnected clusters. After identifying several challenges, an optimized algorithm is proposed to split the large-scale drone swarms more efficiently.

<p> An experimental investigation has been conducted into the reduction of iron oxides under blast furnace conditions. The necessary equipment has been designed, constructed and tested, and a program of study on two types of prereduced ore materials has been completed.</p> / Thesis / Master of Science (MSc)

Ultimate is the fastest growing field sport in America. Created in 1968, forty-five years later the sport was still on the periphery of the mainstream but reached new heights in 2013 – two professional leagues, over 800 college teams and a broadcasting deal with ESPN – and the discussions throughout the sports’ history have never been as relevant. Self-officiation and the Spirit of the Game are the main tenets that make up the ethos of the sport and its community. These unique aspects differentiate Ultimate’s predominate culture from that of mainstream sports culture. This study shows the countercultural ties and survival of the ethos during the adolescent period of Ultimate’s evolution (1987-2010). It examines the progression of the community’s established grassroots culture and the governing body of the sport alongside the influx of young players with mainstream sports attitudes who bolstered certain organizers’ attempts to alter Ultimate in the hopes of gaining “legitimacy” through adding third-party officials, commercialization and corporate sponsorship.

With the rapid proliferation of small unmanned aircraft systems (UAS), the risk of mid-air collisions is growing, as is the risk associated with the malicious use of these systems. The airborne detect-and-avoid (ABDAA) problem and the counter-UAS problem have similar sensing requirements for detecting and tracking airborne threats. In this dissertation, two image-based sensing methods are merged to mimic human vision in support of counter-UAS applications. In the proposed sensing system architecture, a ``peripheral vision'' camera (with a fisheye lens) provides a large field-of-view while a ``central vision'' camera (with a perspective lens) provides high resolution imagery of a specific object. This pair form a heterogeneous stereo vision system that can support range resolution. A novel peripheral-central vision (PCV) system to detect, localize, and classify an airborne threat is first introduced. To improve the developed PCV system's capability, three novel algorithms for the PCV system are devised: a model-based path prediction algorithm for fixed-wing unmanned aircraft, a multiple threat scheduling algorithm considering not only the risk of threats but also the time required for observation, and the heterogeneous stereo-vision optimal placement (HSOP) algorithm providing optimal locations for multiple PCV systems to minimize the localization error of threat aircraft. The performance of algorithms is assessed using an experimental data set and simulations. / Doctor of Philosophy / With the rapid proliferation of small unmanned aircraft systems (UAS), the risk of mid-air collisions is growing, as is the risk associated with the malicious use of these systems. The sensing technologies for detecting and tracking airborne threats have been developed to solve these UAS-related problems. In this dissertation, two image-based sensing methods are merged to mimic human vision in support of counter-UAS applications. In the proposed sensing system architecture, a ``peripheral vision'' camera (with a fisheye lens) provides a large field-of-view while a ``central vision'' camera (with a perspective lens) provides high resolution imagery of a specific object. This pair enables estimation of an object location using the different viewpoints of the different cameras (denoted as ``heterogeneous stereo vision.'') A novel peripheral-central vision (PCV) system to detect an airborne threat, estimate the location of the threat, and determine the threat class (e.g. aircraft, bird) is first introduced. To improve the developed PCV system's capability, three novel algorithms for the PCV system are devised: an algorithm to predict the future path of an fixed-wing unmanned aircraft, an algorithm to decide an efficient observation schedule for multiple threats, and an algorithm that provides optimal locations for multiple PCV systems to estimate the threat position better. The performance of algorithms is assessed using an experimental data set and simulations.

Unmanned aerial systems (UAS) have become wildly popular over the past decade. With the increased demand of these systems, it is imperative for agencies such as the Federal Aviation Administration (FAA) to integrate rules and regulations of UAS into the National Airspace System (NAS). In 2023, a UAS Integration Safety and Security Technology Ontology (ISSTO) was developed in the Web Ontology Language (OWL) to aid in this integration. To further aid UAS integration into the NAS, it becomes necessary to develop methods for training new pilots, air traffic control operators, drone operators, etc. This paper proposes a query application that allows new operators to query through ISSTO and efficiently access UAS and counter-UAS information from the knowledge domains contained within the ontology. These knowledge domains include information on various FAA regulations and authorizations, National Airspace classifications, counter-UAS procedures and more. The application developed in this thesis serves as a proof of concept for a commercialized training product.