In this thesis a method for determining optimal dead space in an axial-type expander is developed. The axial-type expander in question is for use in a steam engine, a environmental friendly and fuel-agnostic alternative to the ICE-engine. Optimal dead space is of importance as an increase in the dead space lowers the efficiency of the engine, however, is needed to ensure operation of expander as the piston could otherwise collide with the expander chamber top surface. The model for determining the optimal dead space in this thesis is based on vectorial tolerance models used for kinematic assemblies, and include the effect of thermal expansion, clearances at joints, manufacturing tolerances and deformations. With resulting tolerances and safety factors, a safe position of the expansion chamber top surface can then be established by Monte Carlo analysis. With input of design variables and the effect from factors mentioned and their effect on the minimal safe distance is calculated using the model in this thesis. From numerical analysis, the factors having the most contribution on the dead space are concluded to be thermal expansion of piston and piston rod, dimensional manufacturing tolerances of piston and piston rod, clearance at ball joints, axial clearance at shaft and bending of Z-shaft. / I detta examensarbete har en metod för att bestämma det optimala avståndet mellan kolv och expansionskammarens högsta yta tagits fram. Axial-kolvmotorn avses för bruk i en ångmotor, ett miljövänligt alternativ till bensin och dieselmotorer som kan drivas med många drivmedel, t.ex. biomassa. Att bestämma detta optimala avstånd är viktigt eftersom en ökning i detta avstånd minskar motorns effektivitet. Dock behövs ett visst avstånd för att säkerställa att ingen kontakt mellan de två ytorna sker under drift. Modellen framtagen i detta examensarbete baserar sig på tolerans analys-modeller med vektorer som används för mekanismer under rörelse. I denna modell inkluderas effekten av termisk expansion, glapp i kontakt mellan komponenter, tillverkningstoleranser och deformationer på kolvens rörelse. Med hjälp av resulterande toleranser och säkerhetsfaktorer kan genom Monte Carlo simulationer ett optimalt avstånd mellan kolv och expansionkammaren bestämmas. Genom inmatning av designvariabler och undersökta effekter kunde genom numerisk analys konstateras att de viktigaste parametrarna att undersöka med störst effekt på axial-kolvmotorn var termisk expansion av kolv och kolvstång, dimensionella toleranser av kolv och kolvstång, glapp i kul-kontakter, axial rörelsefrihet vid kulled och böjning av Z-axel.

A frequency response tracer technique was used to study the hydraulic properties of a laboratory flow through reactor with variations in reactor size, flow rate and applied mixing. At any one set of conditions the reactor was studied over a range of input sine wave frequencies. Theoretical models consisting of in-series networks of completely mixed segments, plug flow segments, and dead space allowances were developed to approximate the experimental findings. / Thesis / Master of Engineering (ME)

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<p>This thesis examines how American icons, such as Jim Morrison, become the focus of "secular" religious followings. Morrison died in Paris, France, in 1971. His grave site, in Paris, attracts thousands of visitors each year. As the lead singer of 1960s era band, The Doors, Morrison achieved extraordinary fame. Tiring of his rock star status, Morrison moved to Paris in 1971, where he died under mysterious circumstances at age 27.</p> <p>After his death, Morrison remained a focus of popular biographies and films; many attributed mythic qualities to the dead singer. The continued interest in the celebrity of Morrison, following his death, generated much popularity among a new generation of fans.</p> <p>The motivation for visiting the Morrison grave, in Paris, is not only the music of Morrison or the Doors. Rather, fans gather in Paris each year to remember Morrison as cultural hero and the values he represents: freedom and rebellion against authority.</p> <p>An ethnography in Paris completed during the anniversary of his death, July 3, supplements an analysis of the subculture surrounding Morrison. A wider conclusion concerning the purpose of dead celebrity followings, in contemporary society, is a final focus.</p> / Master of Arts (MA)

<p>This dissertation examines how human remains are circulated as material culture in contemporary Western society. It is based on an extended period of research and fieldwork carried out from September 2011 to June 2013, in addition to forensic-related research conducted from 2007 to 2010. Through interviews with individuals who handle human remains and an analysis of popular culture via social and mass media, I pose the question: How and why have the undisposed dead been made to occupy a variety of spaces in contemporary Western society; for personal use, education, sale, or veneration?</p> <p>Interviews conducted with Roman Catholic clergy confirm not only the contemporary importance and influence of human relics, but the Church’s ongoing relationship with the dismembered body. This research thus offers a counterpoint to the usual positioning of the Church as anti-science and as imposing a religious taboo toward human remains. I argue instead that the Catholic Church historically has had an important influence on the practices of anatomical dissection, and the deeply embedded Western traditions of making the undisposed dead necessary, popular and culturally acceptable.</p> <p>As an extension of my analysis of the Catholic Church’s traditions and policies around the use of human remains, I examine the institutional handling of the dead in various types of museums and compare this with how human remains are celebrated and circulated in popular culture. Lastly, I explore the work of five controversial visual artists who use human remains in their art.1 Through extensive personal interviews, conducted in their homes and studios, I demonstrate how Catholic bodies, images and symbols have profoundly inspired (rather than discouraged) these visual artists in their personal, as well as artistic narratives.</p> <p>My research shows that, contrary to the academic literature, human remains are neither imbued with fear, nor with notions of violence or taboo; neither are they deployed to symbolically encounter death. In the hands of either institutional or personal collectors, I argue that human remains are valuable commodities through which membership, identity, and knowledge are expressed in contemporary Western society.</p> <p>1 Wayne Martin Belger, Al Farrow, Andrew Krasnow, Mark Prent, Joel Peter Witkin</p> / Doctor of Philosophy (PhD)

The rapid urban development has impacted a great loss of natural landscape in the U.S in recent years. In the process of urbanization, the population has moved from the city centers to the edges of the Metropolitan or the newly developed suburbs as much as 62% until 2000. The annual conversion rate of undeveloped land to developed land between 1982 and 1992 was 1.4 million acres per year while it accelerated later in only five years between 1992 and 1997 to 2.2 million acres per year. Among all the development one of the most common was the Enormous shopping mall in suburban districts which are the collections of a vast range of retail corporations in response to the growing consumerism. In support of the gigantic malls, more service infrastructures were built as in the multi-storied parking garages, surface parking, HVAC. Currently, the total number of malls in the U.S is approximately 116,000. The downside of the development has been observed as rapid as it has grown. As in 2014, nearly 3% of all the malls in the United States were considered to be "dying" (40% or higher vacancy rates) and nearly one-fifth of all malls had vacancy rates considered "troubling" (10% or higher). The sudden deterioration was caused because of several factors such as the socio-economic change of the demography in the urban context, the change in the spending habit of the consumers (i.e. spending for experience rather than goods), Rise of the E-commerce, etc. While the dying circumstance continues, these vast and trapped places have nothing but negative impacts in the urban environment as being wasteful land, blocking the visual connectivity through places, clogging the pedestrian flow, contributing to the heat island effect. Thus the problem is evoking to rethink a sustainable design approach. This thesis will first generate an adaptive master plan for the future, in a specific site as the result of investigating the socio-economic issues that forced the mall site to be vacant. After projecting the master plan, the architectural project will be proposed which will prioritize the physical and social development of the context. Educating people regarding the redevelopment of the community and the sustainable way of living are the key features of the project. The new project will be considered an iconic community asset that would serve the neighborhoods. / Master of Architecture / The rapid urban development has impacted a great loss of natural landscape in the U.S in recent years. In the process of urbanization, the population has moved from the city centers to the edges of the Metropolitan or the newly developed suburbs as much as 62% until 2000. To serve the resettled population new services have been developed at the outskirts of the cities. Among all the development one of the most common was the Enormous shopping mall in suburban districts which are the collections of a vast range of retail corporations in response to the growing consumerism. In support of the gigantic malls, more service infrastructures were built as in the multi-storied parking garages, surface parking, HVAC. Currently, the total number of malls in the U.S is approximately 116,000. The downside of the development has been observed as rapid as it has grown. As in 2014, nearly 3% of all the malls in the United States were considered to be "dying" (40% or higher vacancy rates) and nearly one-fifth of all malls had vacancy rates considered "troubling" (10% or higher). The sudden deterioration was caused because of several factors such as the socio-economic change of the demography in the urban context, the change in the spending habit of the consumers (i.e. spending for experience rather than goods), Rise of the E-commerce, etc. This thesis will explore the strategy for reintegrating the troubling mall sites within the urban fabric. The thesis will first generate an adaptive master plan for the future, in a specific site as the result of investigating the socio-economic issues that forced the mall site to be vacant. After projecting the master plan, the architectural project will be proposed which will prioritize the physical and social development of the context. Educating people regarding the redevelopment of the community and the sustainable way of living are the key features of the project. The new project will be considered an iconic community asset that would serve the neighborhoods.

京都大学 / 新制・課程博士 / 博士(生命科学) / 甲第25455号 / 生博第526号 / 新制||生||70(附属図書館) / 京都大学大学院生命科学研究科高次生命科学専攻 / (主査)教授 原田 浩, 教授 永尾 雅哉, 教授 松本 智裕 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM

Motivated by the recent commercialization of gallium-nitride (GaN) switches, an effort was initiated to determine whether it was feasible to switch the flyback converter at 5 MHz in order to improve the power density of this versatile isolated topology. Soft switching techniques have to be utilized to eliminate the switching loss to maintain high efficiency at multi-megahertz. Compared to the traditional modeling of zero-voltage-switching quasi-square-wave converters, a numerical methodology of parameters design is proposed based on the steady-state model of zero-voltage switching quasi-square-wave flyback converter. The magnetizing inductance is selected to guarantee zero-voltage switching for the entire input and load range with the trade-off design for conduction loss and turn-off loss. A design methodology is introduced to select a minimum core volume for an inductor or coupled inductors experiencing appreciable core loss. The geometric constant Kgac = MLT/(Ac2WA) is shown to be a power function of the core volume Ve, where Ac is the effective core area, WA is the area of the winding window, and MLT is the mean length per turn for commercial toroidal, ER, and PQ cores, permitting the total loss to be expressed as a direct function of the core volume. The inductor is designed to meet specific loss or thermal constraints. An iterative procedure is described in which two- or three-dimensional proximity effects are first neglected and then subsequently incorporated via finite-element simulation. Interleaved and non-interleaved planar PCB winding structures were also evaluated to minimize leakage inductance, self-capacitance and winding loss. The analysis on the trade-off between magnetic size, frequency, loss and temperature indicated the potential for a higher density flyback converter. A small-signal equivalent circuit of QSW converter was proposed to design the control loop and to understand the small-signal behavior. By adding a simple damping resistor on the traditional small-signal CCM model, it can predict the pole splitting phenomenon observed in QSW converter. With the analytical expressions of the transfer functions of QSW converters, the impact of key parameters including magnetizing inductance, dead time, input voltage and output power on the small-signal behavior can be analyzed. The closed-loop bandwidth can be pushed much higher with this modified model, and the transient performance is significantly improved. With the traditional fix dead-time control, a large amount of loss during dead time occurred, especially for the eGaN FETs with high reverse voltage drop. An adaptive dead time control scheme was implemented with simple combinational logic circuitries to adjust the turn on time of the power switches. A variable deadtime control was proposed to further improve the performance of adaptive dead-time control with simplified sensing circuit, and the extra conduction loss caused by propagation delay in adaptive dead-time control can be minimized at multi-megahertz frequency. / Ph. D. / With the fast development of telecom, computer and network systems, high efficient and small volume power supplies are highly desired. A typical method for achieving high power density involves increasing the frequency and implement soft-switching techniques to minimize loss. Thanks to the recent commercialization of the advanced semiconductor gallium-nitride (GaN) switches, it is feasible to design high density power supplies and cost effective power system. Several challenges including optimization of power converter, high frequency magnetics and implementation of control architecture have been addressed in this dissertation which helps to realize this compact power system. With the implementation of proposed circuit model and seminumerical design procedures for magnetics, a 30W high-frequency isolated DC/DC converter with planar inductor is fabricated to verify the theoretical analysis, which also demonstrates much improved performances.

Current control is an important topic in modern power electronics system. For voltage source inverters, current control loop ensures the waveform quality at steady state and the fast response at transient state. To improve the current control performance, quite a few nonlinear control strategies have been presented and one well-known strategy is the hysteresis current control. It achieves fast response without stability issue and it has high control precision. However, for voltage source inverter applications, hysteresis current control has a wide switching frequency range, which introduces additional switching loss and impacts the design of harmonic filter. Other nonlinear current control strategies include one-cycle control, non-linear carrier control, peak current control, charge control, and so on. However, these control strategies are just suitable for specific topologies and it cannot be directly used by voltage source inverters. The recently proposed parabolic current control solves the frequency variation problem of hysteresis current control by employing a pair of parabolic carriers as the control band. By the use of parabolic current control, approximate-constant switching frequency can be achieved. Due to the cycle-by-cycle control structure, it inherently has fast response speed and high precision. These advantages make it suitable for voltage source inverters, including stand-alone inverters, grid connected inverters, active power filters, and power factor correction applications. However, parabolic current control has some limitations, such as dead-time effects, only working as bipolar PWM, complex hardware implementation, non-ideal converging speed. These problems are respectively solved in this dissertation and solutions include dead-time compensation, the implementation on dual-carrier unipolar PWM, sensorless parabolic current control, single-step current control. With the proposed dead-time compensation strategy, current control precision is improved and stable duty-cycle range are extended. Dual-carrier PWM implementation of parabolic current control has smaller harmonic filter size and lower power loss. Sensorless parabolic current control decreases the cost of system and enhances the noise immunity capability. Single-step current control pushes the convergence speed to one switching operation with simple implementation. High switching frequency is allowed and power density can be improved. Detailed analysis, motivation and experimental verification of all these innovations are covered in this dissertation. In addition, the duality phenomenon exists in electrical circuits, such as Thevenin's theorem and Norton's theorem, capacitance and inductance. These associated pairs are called duals. The dual of parabolic current control is derived and named parabolic voltage control. Parabolic voltage control solves the audible noise problem of burst mode power converters and maintains high efficiency in the designed boost converter. / Ph. D. / Current control strategy is an important topic in power converter design. Good current control strategy helps to control the quality of input or output waveform of power conversion systems. This dissertation studied an attractive current control strategy named parabolic current control. Parabolic current control solves some drawbacks of conventional current control strategies with enhanced performance. However, it still has some application limitations. This dissertation proposed four new strategies to solve the application limitations of parabolic current control. Motivated by the duality phenomenon, a voltage control strategy named parabolic voltage control is also proposed, serving as the dual of parabolic current control. By the use of parabolic voltage control, audible noise in some power conversion systems can be eliminated and conversion efficiency can be ensured. All these new ideas in this dissertation are carefully derived in theory and verified by experimental test results.