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

京都大学 / 新制・課程博士 / 博士(工学) / 甲第25017号 / 工博第5194号 / 新制||工||1991(附属図書館) / 京都大学大学院工学研究科化学工学専攻 / (主査)教授 外輪 健一郎, 教授 松坂 修二, 教授 佐野 紀彰 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Autonomous vehicle technology has seen remarkable advancements in recent years, yet significant challenges remain in ensuring robust, adaptive, and efficient control algorithms for diverse operational scenarios. This dissertation aims to address these challenges by developing and validating a generic control framework that is applicable to both independent autonomous vehicles and connected vehicle systems such as automated platoons. The versatility of the proposed framework ensures its applicability to a wide range of vehicles, including automobiles, light trucks, and rigid and articulated commercial trucks, under high-speed and complex driving conditions. The first major contribution is the development of a longitudinal control algorithm based on a nested PID structure. Designed for computational efficiency and stability, the algorithm simultaneously regulates vehicle speed and inter-vehicle distance. Its adaptability is extended to curved trajectories using an arc length-based error calculation, making it suitable for real-world scenarios. A rigorous simulation study is undertaken to demonstrate the algorithm's stability and robustness to parametric uncertainties. The second major contribution is the development of a high-speed lateral control algorithm based on a modified clothoid controller. This lateral control framework is designed to minimize lateral acceleration (improving passenger comfort and safety) and reduce cross-track errors (CTEs) across various vehicle configurations, including articulated trucks. Simulation results confirmed the superiority of the clothoid-based controller in minimizing CTEs and maintaining smooth steering profiles, even for complex vehicle configurations. Notably, tracking the steer axle center was found to significantly improve performance across all trajectory segments. The final contribution integrates the longitudinal and lateral control frameworks, enabling seamless operation in automated platooning scenarios. This integration requires adapting the longitudinal controller to curved trajectories using arc length-based calculations. Comprehensive simulations, including challenging trajectories such as dual lane changes, and actual roadways like sections of the Blue Ridge Parkway in Virginia and South Grade Road in California, validated the integrated framework. Despite minor anomalies in high-stress conditions, the results demonstrate acceptable performance in terms of spacing errors, relative velocities, lateral accelerations, and CTEs, highlighting the robustness and resilience of the proposed system. The study presents a unified control framework that bridges the gap between independent autonomous vehicles and connected vehicle systems. The generic nature of the algorithms ensures their applicability to a wide variety of vehicles and scenarios, making them a strong candidate for future deployment in autonomous systems. The findings represent significant advances toward safer, more efficient, and versatile autonomous vehicle technologies, addressing critical challenges in the path to commercial implementation / Doctor of Philosophy / Autonomous vehicles are transforming the way we think about transportation, but challenges remain in making these systems adaptable, efficient, and safe across different driving conditions. This research focuses on creating a versatile control system that works for both individual autonomous vehicles, like self-driving cars, and connected systems, such as a platoon (group) of automated trucks traveling together, in a synchronized manner. The framework is designed to handle a wide range of vehicles, including both cars, light trucks, and large trucks with trailers, even in high-speed and complex scenarios. The first contribution is a computationally efficient and robust longitudinal control algorithm to control vehicle speed and spacing between vehicles. It efficiently regulates the vehicle speed and inter-vehicle distance and is extended to handle the trajectory that the vehicle takes on curved roadways, using arc length-based error calculations. The simulation results show that this approach is both reliable and robust, even when faced with uncertainties like changing vehicle loads or road conditions. The second contribution is a high-speed lateral control algorithm using a modified clothoid controller. This controller minimizes lateral acceleration for improved safety and comfort while reducing cross-track errors (CTEs) for both rigid-body and articulated vehicles. It is discovered that tracking the steer axle center, as opposed to other points of reference on the vehicle, significantly enhances performance across all trajectory types. Finally, the longitudinal and lateral controllers are integrated for automated platooning, with adaptations for curved trajectories. This integrated system is tested on challenging road layouts, including sharp turns and steep inclines, showing it can maintain safe distances and smooth paths even under difficult conditions. The roadways selected for evaluating the control scheme include a section of the Blue Ridge Parkway in Virginia and a section of the South Grade Road in California. In summary, this research provides a flexible and efficient control system that bridges the gap between self-driving cars and larger connected vehicle systems. By making it adaptable to various vehicles and scenarios, it lays the foundation for safer and more reliable autonomous vehicle technology in the future

Solid fuel ramjets (SFRJs) are a simple means of sustaining supersonic flight. The utilization of solid fuels eliminates the need for moving parts or liquid delivery systems, and the solid fuels are typically inert, resulting in minimal handling requirements compared to solid propellants. Characteristic of SFRJ systems are the relatively high combustor velocities and the required gasification of the solid fuel prior to releasing heat through gas-phase reactions. The primary objectives of the current work were to investigate the decomposition behavior of model solid fuels typically used in SFRJ systems and to employ a novel fuel geometry to increase the flame-holding limits of an SFRJ. Two bench-scale solid fuel experiments were conducted to capture relevant performance metrics of five solid fuels. Performance parameters such as regression rates, surface temperature variations, molten layer thickness, and condensed-phase kinetic behavior were analyzed using a non-combusting laser pyrolysis experiment. Further investigations were performed for each fuel using a modified counterflow burner, which served as an analog for the boundary layer combustion in an SFRJ by introducing the effects of flame heat feedback to the fuel surface. General trends among the fuels were identified, and several mechanistic differences in the decomposition process were discussed with consideration of condensed-phase behavior. The results from the laser pyrolysis and counterflow burner studies were subsequently used as validation data for the development of a solid fuel decomposition model incorporating single-step decomposition, transient heat transfer, and surface heat losses. The developed model showed reasonable agreement with experimental pyrolysis results, particularly for regression rates and surface temperatures of polymethylmethacrylate (PMMA) and hydroxyl-terminated polybutadiene (HTPB). Investigations using two lab-scale SFRJs were conducted to determine the feasibility and performance impacts of implementing a cavity-style flame holder as a means of improving the flammability limits of a SFRJ. The results presented demonstrate the effectiveness of such a method showing that introducing a cavity flame holder enables significantly higher fuel loading in the present system. The effects of the alternate geometries on local regression rates are reported and a high local heat flux at the cavity corner is identified as a strong factor in the increased flame holding capability. The increased regression rates contribute to higher observed chamber pressures while the effects on combustion efficiency are observed to be minimal. Further investigation of the cavity geometries using an optically accessible SFRJ allowed the analysis of the reacting flow field. High-speed chemiluminescence, high-speed videography, and high-speed three-color camera pyrometry provided further insight into the reacting flow and identified key reaction regions relevant to flame holding. Observations of the spatial regression rate show similar trends to the initial experiments, revealing a large increase in regression rate associated with the cavity corner. The regression rates and observations regarding the size of the recirculation region were incorporated into a semi-empirical model describing the behavior of the recirculation region and point to the increased fuel flow rate resulting from the cavity corner as a contributing factor in the increased flammability of the cavity fuel grains. / Doctor of Philosophy / Solid fuel ramjets (SFRJs) are high-speed air-breathing propulsion devices that utilize the surrounding air in combination with a solid fuel to generate thrust. A primary problem in applying these devices is creating an environment inside the SFRJ that can support stable combustion due to the relatively high velocity of the incoming air. This study seeks to improve the capabilities and therefore the operational limits of solid fuel ramjets by investigating the effects of new fuel geometries that provide more favorable conditions for sustained flame holding. In addition, an investigation of solid fuels is conducted to investigate some of the key processes involved with the heating, decomposition, and combustion of solid fuels as it applies to high-speed air breathing propulsion applications.

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 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.

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.