This dissertation explores a novel omnidirectional propulsion mechanism for observation-class underwater vehicles, enabling for operation in extreme, hostile, or otherwise high-speed turbulent environments where unprecedented speed and agility are necessary. With a small overall profile, the mechanism consists of two sets of counter-rotating blades operating at frequencies high enough to dampen vibrational effects on onboard sensors. Each rotor is individually powered to allow for roll control via relative motor effort and attached to a swashplate mechanism, providing quick and powerful manipulation of fluid-flow direction in the hull's coordinate frame without the need to track rotor position. The omnidirectional mechanism exploits properties emerging from its continuous counter-rotating blades to generate near-instantaneous forces and moments in six degrees of freedom (DOF) of considerable magnitude, and is designed to allow each DOF to be controlled independently by one of six decoupled control parameters. The work presented in this dissertation validates the mechanism through physical small-scale experimentation, confirming near-instantaneous reaction time, and aligning with computational fluid dynamic (CFD) results presented for the proposed theorized full-scale implementation. Specifically, it is demonstrated that the mechanism can generate sway thrust at 10-20% surge thrust capacity in both simulation and physical tests. It is also shown that the magnitude of forces and moments generated is directly proportional to motor effort and corresponding commands, in par with theory. Any apparent couplings between different control modes are deeply understood and shown to be trivially accounted for, effectively uncoupling all six control parameters. The design, principles, and bullard-pull simulation of the proposed full-scale mechanism and vehicle implementation are then thoroughly discussed. Kinematic and hydrodynamic analyses of the hull and surrounding fluid forces during different maneuvers are presented, followed by the mechanical design and kinematic analysis of each subsystem. To estimate proposed full-scale performance specifications and UUV turbulence rejection, a full six-DOF maneuvering model is constructed from first principles utilizing CFD and regression techniques. This dissertation thoroughly examines the working principles and performance of a novel omnidirectional propulsion mechanism. With the small-scale model and full scale simulation and analysis, the work presented successfully demonstrates the mechanism can generate nearly instantaneous omnidirectional forces underwater in a controlled manner, with application to high-speed agile vehicles in dynamic environments. / Doctor of Philosophy / This dissertation explores a novel omnidirectional propulsion mechanism for observation-class underwater vehicles, enabling for operation in extreme, hostile, or otherwise high-speed turbulent environments where unprecedented speed and agility are necessary. The mechanism utilizes independently-powered rotors to command near-instantaneous forces and moments in all six degrees of freedom (DOF). The design allows each DOF to be independently controlled by one of six decoupled control parameters. The method for generating lateral thrust through the mechanism is originally verified through computational fluid dynamic (CFD) tests, but the complete novelty of the lateral maneuver calls for physical verification for any noteworthy validation. The work presented in this dissertation validates the mechanism through physical small-scale experimentation, confirming near-instantaneous reaction time, and aligning with CFD results presented for the proposed theorized full-scale implementation. Specifically, it is demonstrated that the mechanism can generate sway (side/side) thrust at 10-20% surge (forward/backward) thrust capacity in both simulation and physical tests. It is also shown that the magnitude of forces and moments generated is directly proportional to motor effort and corresponding commands, in par with theory. Finally, a full six-DOF model for underwater vehicle trajectory is constructed utilizing detailed maneuvering techniques to estimate full-scale performance. With the small-scale model and full-scale simulation and analysis, the work successfully demonstrates the mechanism can generate nearly instantaneous omnidirectional forces underwater in a controlled manner, with application to high-speed agile vehicles in dynamic environments.

This project examines the construction of the Taiwan high-speed rail (THSR; 台灣高鐵) technology as a vehicle of Taiwanese identity formation. The THSR project is a product of a hybridization of design from Japan and Europe. The Japanese and Europeans transferred their HSR technology to Taiwan, but Taiwanese policy actors and engineers localized and assimilated it to their politics, society and history. They reconstructed the meanings of HSR technology in an indigenized (Ben-Tu-Hua; 本土化) and democratic way. In addition to focusing on the THSR's technological content and engineering practice, this dissertation explores how Taiwan identity formation has shaped technology and vice versa. The identity formation and technological construction in Taiwan tell one techno-political story. Since the 1960s and 1970s, Taiwanese engineers were forced by international politics to cannibalize technological projects, but later they began to localize and hybridize different foreign engineering skills and knowledge. This growing engineering culture of hybridity generated impacts on the development of Taiwan's identity politics. Some critical political leaders exploited their engineers' capability to hybridize to introduce international power into Taiwan. This power then was used to either strengthen the Taiwanese population's Chinese identity or to build their Taiwanese identity. Both politics and technology offered each other restrains and opportunities. This project offers an approach from science and technology studies to understand postcolonial technopolitics. The engineering practice of hybridity in Taiwan has become a locally transformed knowledge to reframe and negotiate with the more advanced technologies from the West and Japan, even though it was a contingent outcome of earlier international politics. In addition to technological non-dependence, this engineering culture of hybridity has given the Taiwanese an independent political vision not only against China but the West and Japan. However, Taiwan paid significant prices to acquire technological non-dependence and international independence. In addition to extra wasted money and time, some over design was often seen in their public projects. Large technological projects also often draw political patronage. Moreover, techno-political survival alone might not be enough to represent postcolonial resistance. / Ph. D.

The objective of this study is to set a methodology for the economic evaluation of high speed ground transportation systems. The main objective of this study is to establish a systematic framework, in order that planners can quickly understand and analyze the implications that different policies have on the life-cycle of the transportation system. The methodology is adaptable for different modes and also for different locations at which similar systems could be implemented. The mode under consideration here is that of Magnetically levitated vehicles and the study area is the Northeast corridor of the United States. The economic evaluation is based on a Systems Dynamics simulation model. The model incorporates socioeconomic parameters, trip generation, mode split, traffic engineering, economic parameters and elements of mass transportation. The interactions within these subsystems and between them are studied through various policy analysis which were conducted. The range of policy covers socioeconomic parameters, traffic strategies and economic parameters. Life cycle costs and revenues are the key performance indicators. Parameters such as elasticity values were assumed based on previous studies conducted in other locations. Revenues from fares is the only benefit considered for implementation of the new transportation system. The model has been developed so that it can be expanded so as to include various other benefits from maglev implementation. The model is highly flexible and can be used for a wide range of policy analysis. With regard to magnetic levitated transportation system it was found to be an economically feasible transportation alternative to solve the problems facing high speed inter-city travel. The life cycle costs of such a venture were found to be highly sensitive to the cost of power and the elasticity values associated with the trip generation model. / Master of Science

High operation speeds and thin coating films are desirable in many industrial applications. But the quality of the product, which is primarily determined by an optimum process window, is affected by non-uniformities and instabilities originating at higher operation speeds. Unlike other academic works, because of associated industrial relevance, particular attention was given towards the use of industrially relevant coating systems or generation of model fluids, which replicate the real coating solutions. One of the novelties of the research proposed lie in an integrated approach, utilising a range of comparative rheometrical techniques, with a focus on measurement of: (i) high strain rate shear viscosity [η], (ii) high strain rate uniaxial extensional viscosity [ηE] (iii) high strain rate elasticity (N1). Deformable roll coating, in terms of classification, is the ultimate metered coating flow. The flow is controlled by the combination of hydrodynamic force and elastic deformation effect, which could be complicated by the presence of non-Newtonian fluid. This study necessitated the design and construction of a sophisticated deformable coating rig with the ability to operate over a wide range of conditions. Although the irregularities and instabilities associated with the roller coating process has been studied previously, the concerned speeds of operation in this study is around three times higher. The main objectives of this study was to carry out a comprehensive experimental programme establishing relationship exist between film thickness, film quality and operating parameters. Main identified operating parameters are roll speeds, roll gaps or applied load between the rolls, the elasticity with thickness of elastomeric layer and different rheological properties of the coating fluids. Surface instabilities and air entrainment are identified as the major limitations to being able to coat at higher speeds. / Tata Steel Europe / The full text was made available at the end of the embargo, 1st July 2020

Software defined radios have the potential of changing the fundamental usage model of wireless communications devices, but the capabilities of these transceivers are often limited by the speed of the underlying processors and FPGAs. This thesis presents the digital design for an impulse-based ultra wideband communication system capable of supporting raw data rates of up to 100 MB/s. The transceiver is being developed using software/reconfigurable radio concepts and will be implemented using commercially available off-the-shelf components. The receiver uses eight 1 GHz ADCs to perform time interleaved sampling at an aggregate rate of 8 Gsamples/s. The high sampling rates present extraordinary demands on the down-conversion resources. Samples are captured by the high-speed ADC and processed using a Xilinx Virtex-II Pro (XC2VP70) FPGA. The testbed has two components: a non real-time part for data capture and signal acquisition, and a real-time part for data demodulation and signal processing. The overall objective is to demonstrate a testbed that will allow researchers to evaluate different UWB modulation, multiple access, and coding schemes. As proof-of-concept, a scaled down prototype receiver which utilized 2 ADCs and a Xilinx Virtex-II Pro (XC2VP30) FPGA was fabricated and tested. / Master of Science

Increasing interest in ultra-wideband (UWB) communications has engendered the need for a test bed for UWB systems. An FPGA-based software-defined radio provides both post-fabrication definition of the radio and ample parallel processing power. This thesis presents the FPGA design for a software-defined radio targeted to impulse ultra-wideband signals. The system is capable of an effective sampling frequency of up to 8 G-samples/s using time interleaved sampling with eight 1-GHz ADCs. The system is also capable of transmitting UWB pulses using a transmitter board controlled by the FPGA. In this thesis, the FPGA design used to capture and export data from the eight ADCs is presented, along with two systems which make use of the transceiver: a pilot-based matched filter communications system, and a remote vital signs monitor. / Master of Science

Yes / PolyEtherKetone (PEK) is a suitable material for tribological systems which specifically require the properties of high chemical resistance, low component weight, seizure resistance under starved lubrication conditions and operation at higher temperatures than many other engineering polymers can survive. PEK is used with a liquid lubricant at high temperatures and velocities to reduce friction and also to control unstable friction and wear, particularly in the region of the material’s glass transition temperature, Tg. Intermittent and marginal lubrication using representative high temperature synthetic lubricants was applied to high speed, high temperature PEK/steel sliding contacts to determine the effectiveness of lubrication under these conditions. Variations in the stability of the thin lubricant films were observed, particularly under different load conditions. Under low load conditions, the lubricant polarity and the related ability to form a film in the contact was important. Under high load conditions, the thermal stability of the lubricant became more important in retaining stability in the friction and wear mechanisms. Whilst not ideal practice, marginal lubrication of PEK-steel sliding contacts can be achieved by selection of an appropriate lubricant, even in the glass transition region of PEK. / Innovate UK Knowledge Transfer Partnership (KTP) grant, No. 8092.

High speed video has been a significant tool for unraveling the quantitative and qualitative assessment of phenomena that is too fast to readily observe. It was first used in 1852 by William Henry Fox Talbot to settle a dispute with reference to the synchronous position of a horse's hooves while galloping. Since that time private industry, government, and enthusiasts have been measuring dynamic scenarios with high speed video. One challenge that faces the high speed video community is the dynamic range of the sensors. The dynamic range of the sensor is constrained to the bit depth of the analog to digital converter, the deep well capacity of the sensor site, and baseline noise. A typical high speed camera can span a 60 dB dynamic range, 1000:1, natively. More recently the dynamic range has been extended to about 80 dB utilizing different pixel acquisition methods. In this dissertation a method to extend the dynamic range will be presented and demonstrated to extend the dynamic range of a high speed camera system to over 170 dB, about 31,000,000:1. The proposed formation methodology is adaptable to any camera combination, and almost any needed dynamic range. The dramatic increase in the dynamic range is made possible through an adaptation of the current high dynamic range image formation methodologies. Due to the high cost of a high speed camera, a minimum number of cameras are desired to form a high dynamic range high speed video system. With a reduced number of cameras spanning a significant range, the errors on the formation process compound significantly relative to a normal high dynamic range image. The increase in uncertainty is created from the lack of relevant correlated information for final image formation, necessitating the development of a new formation methodology. In the proceeding text the problem statement and background information will be reviewed in depth. The development of a new weighting function, stochastic image formation process, tone map methodology, and optimized multi camera design will be presented. The proposed methodologies' effectiveness will be compared to current methods throughout the text and a final demonstration will be presented. / Ph. D. / High speed video is a tool that has been developed to capture events that occur faster than a human can observe. The use and prevalence of high speed video is rapidly expanding as cost drops and ease of use increases. It is currently used in private and government industries for quality control, manufacturing, test evaluation, and the entertainment industry in movie making and sporting events. Due to the specific hardware requirements when capturing high speed video, the dynamic range, the ratio of the brightest measurement to the darkest measurement the camera can acquire, is limited. The dynamic range limitation can be seen in a video as either a white or black region with no discernible detail when there should be. This is referred to as regions of over saturation or under saturation. Presented in this document is a new method to capture high speed video utilizing multiple commercially available high speed cameras. An optimized camera layout is presented and a mathematical algorithm is developed for the formation of a video that will never be over or under saturated using a minimum number of cameras. This was done to reduce the overall cost and complexity of the setup while retaining an accurate image. The concept is demonstrated with several examples of both controlled tests and explosive tests filmed up to 3,300 times faster than a standard video, with a dynamic range spanning over 310,000 times the capabilities of a standard high speed camera. The technology developed in this document can be used in the previously mentioned industries whenever the content being filmed over saturates the imager. It has been developed so it can be scalable in order to capture extremely large dynamic range scenes, cost efficient to broaden applicability, and accurate to allow for a fragment free final image.

Sverige planerar för en av de största infrastrukturinvesteringarna någonsin i Sveriges historia. I fokus står en ny höghastighetsjärnväg mellan Stockholm, Göteborg och Malmö som ska möjliggöra resor på två till två och en halv timme mellan städerna. Runt denna investering finns en ambition att samla andra samhällsbyggande åtgärder, som ökat bostadsbyggande och förbättringar i lokal och regional kollektivtrafik, för att genom en samordnad planering få ut så stora nyttor som möjligt. För detta ändamål har regeringen tillsatt den statliga utredningen Sverigeförhandlingen. En viktig del av deras arbete är att få fram en finansieringslösning för den nya statliga transportinfrastrukturen där medfinansiering från kommuner, regioner och andra aktörer står för en betydande andel. Idén kring medfinansiering är baserad på att aktörerna ska bidra till finansieringen som motsvarar de nyttor transportinfrastrukturen bidrar till. Alltså måste det gå att uppskatta att på förhand hur mycket nyttor som uppstår och vad de är värda. Sverigeförhandlingen har valt klassificera nyttorna i sex kategorier där ”social nyttor” är en av dessa. Däremot finns ingen etablerad metodik för att uppskatta dessa. Det här examensarbetet undersöker vilken social påverkan transportinfrastrukturen ger upphov till. Detta görs genom att studera samband mellan tillgänglighet, alltså hur transportinfrastrukturen ger möjlighet för människor att nå olika målpunkter, och ett antal sociala förhållanden. Tillgänglighetsmåttet valdes utifrån studier av tidigare forskning samt etablerade modeller för uppskattning av andra nyttor av transportinfrastruktur. För att veta vilka sociala förhållanden som är intressanta att undersöka har en studie av Svensk och internationell litteratur på området genomförts. Sambandsanalysen bygger på statistiska metoder där data för Sveriges kommuner används. Metoden ger möjlighet till att identifiera samvariation mellan tillgänglighet och sociala förhållanden men är inte tillräcklig för att säkerställa att tillgänglighet är en orsak till de sociala förhållandena. Resultaten tyder på att tillgänglighet har statistiskt signifikanta samband med ett antal indikatorer för sociala förhållanden. Exempel på två av dessa är ungdomsidrottande och andelen barn som går i förskola. Det visade sig att de flesta av de sociala förhållanden som har signifikanta samband med tillgänglighet har en samvariation som tyder på att tillgänglighet korrelerar med positiva sociala förhållanden. Detta tyder på att tillgänglighet kan ha samband med faktorer som kan tolkas som sociala nyttor. Dock kan inget sägas om tillgänglighet är en orsak till detta eller om det är någon icke studerad orsak som ger upphov till detta. Dessutom påverkas tillgänglighetsmåttet av andra faktorer än enbart tillgång till transportinfrastruktur och därför går det inte utifrån dessa samband att säkert säga att de beror på transportsystemet. För att sociala nyttor ska kunna kvantifieras och ligga till grund för medfinansiering krävs vidare studier. En viktig uppgift är att med hjälp av bättre data och mer avancerade metoder få fram bättre uppskattningar av sambanden samt orsaksrelationerna. Det krävs också studier för hur sociala nyttor ska värderas i monetära termer ur ett samhällsekonomiskt perspektiv. / Sweden is currently planning for one of its largest investments in transport infrastructure ever. A cornerstone in the project is a new high speed railroad between Stockholm, Gothenburg and Malmö. A considerable portion of the funding will consist of co-funding from municipalities, regions and private actors that will benefit from the infrastructure. The amount of co-funding is based on the total benefits that each actor will receive. Therefore these benefits must be able to be quantified. This report aims to study relationships between transport infrastructure and a number of social consequences that previous research has indicated being interesting. The method used is based on econometric methods that enable identification of statistical relationships using a simple linear model. This requires measures of transport infrastructure and indicators for social well-being which are chosen through a study of literature and established models quantifying wider economic benefits from transport infrastructure.The report suggests that a gravitybased accessibility measure is suitable for quantifying transport infrastructure in this context. The results from the econometrical model ssuggest that there are several significant relationships between accessibility and social well-being. In general accessibility seems to correlate with positive social consequences. However it is likely that endogeneity is biasing the results and make it difficult to draw any conclusions on causal relationships. It is stated that further research studying these relationships more carefully with better adapted data for the purpose is required to be able to obtain quantified estimates that can be used in co-funding of transport infrastructure.

Atualmente, nota-se um crescimento na fabricação de produtos utilizando moldes e matrizes contendo formas geométricas complexas. No entanto, a fabricação destes ferramentais onde se emprega, principalmente, operações de fresamento, não tem acompanhado esta evolução com a mesma velocidade. O advento dos sistemas CAD/CAM, máquinas CNC e da tecnologia de usinagem em altas velocidades (HSC) influenciaram positivamente a fabricação de superfícies complexas. Contudo, nota-se ainda ineficiências neste processo produtivo. A qualidade superficial após as operações de usinagem ainda não é suficiente para que estes ferramentais entrem diretamente na linha de produção. Assim, operações manuais de acabamento são exigidas, elevando o tempo e custo de produção, comprometendo a qualidade dimensional. Com a finalidade de aprimorar a fabricação de moldes e matrizes, este trabalho apresenta uma revisão bibliográfica sobre a usinagem HSC; um estudo sobre a força de usinagem para o fresamento de formas complexas e uma análise sobre a metodologia utilizada por sistemas CAD/CAM e CNC para gerar e interpretar programas NC que contenham movimentações complexas de ferramenta. Análises práticas foram realizadas em um centro de usinagem HSC, e os resultados indicam que as limitações tecnológicas atuais na cadeia CAD/CAM/CNC limitam a usinagem de formas complexas com altas velocidades, reduzindo a velocidade de avanço programada e que as características intrínsecas deste processo de remoção de material demonstrou ser bastante complexo, acarretando em constantes alterações na força de usinagem / In recent years the number of products containing free-form shapes produced by dies and molds have been growing noticeably. However, the milling process used to manufacture those dies and molds does not meet their requirements. The arrival of the CAD/CAM systems and the High Speed Cutting Technology (HSC) helps to improve this manufacturing process. Although to obtain the surface quality needed to meet the dies and molds requirements, a hand finishing still requires. It involves time, money and decrease the product quality. Technological limitations in the CAD/CAM/CNC chain limit the feed rate when milling free-form shape. It also has a negative effect on the surface roughness. Besides, this kind of milling still lacks scientific knowledge of the cutting process. With the aim to support the dies and moulds fabrication, this work presents an overview about HSC Technology; the cutting forces in a non-planar milling; the cutting tool deflection; a detailed description of the process chain involving the CAD/CAM/CNC systems and the methodologies used by those systems to generate and accomplish free-free tool-paths. Free-form milling experiments applying the HSC Technology were made to study the behavior of this process, and the outcomes are presented