Introduction Transient global amnesia (TGA) is a condition associated with temporary anterograde amnesia with or without retrograde amnesia, often resolving within 24 hours. It is mostly prevalent in elderly women with a mean age of 60-65 years and may be triggered by acute stressors like emotional trauma, strenuous exercise, Valsalva maneuver, sudden change in body temperature, intense pain, medical procedures, and sexual intercourse. We present a case of 62-year-old female who presented with transient global amnesia while having sexual intercourse. Case presentation 62-year-old female with no significant past medical history presented after having an acute mental status change during sexual intercourse. The episode began with the patient turning her head, and having a staring spell that lasted for few seconds following which she was disoriented to place and was asking same questions repeatedly. The patient was repeatedly asking where she was and where her handbag was during the episode which lasted almost 2 hours during which she was brought to the hospital. Review of systems was negative for any focal weakness, sensory loss, headache, seizures. She denied having any prior episodes of memory loss, migraines, syncope, stroke like symptoms or psychiatric conditions. Social history was only significant for occasional alcohol use but denied tobacco or recreational drug use. On the physical exam, the patient was alert, awake and oriented. Her cognition was intact. No focal neurological or cranial nerve deficits were noted. Lab workup was unremarkable except for slight hypokalemia. CT head without contrast and CT angiogram of head were unremarkable. The patient was diagnosed with TGA and was observed overnight with supportive care. MRI brain with and without contrast next day after the event only revealed tiny punctate area of susceptibility artifact within the right posterior parietal lobe. Patient and family were reassured and was discharged home. Discussion TGA is a condition accompanied by temporary anterograde amnesia with repetitive questioning. TGA has an incidence of 5.2 to 10 per 100,00 per year. Common risk factors include older age, migraines, and rarely familial causes. Most possibly related to neurological damage in median temporal lobe or hippocampus as these areas are strongly associated with memory formation. Potential etiologies include arterial ischemia, venous congestion and cortical spreading depression seen in migraine. TGA is a diagnosis of exclusion, only after ruling out other differential diagnosis like hypoglycemia, acute intoxication, transient ischemic attack, drug withdrawal and Wernicke's encephalopathy. Patients need to be admitted for observation until the amnesia resolves. Neuroimaging helps rule out serious pathologies and EEG may be considered in patients with high clinical suspicion for seizure. No specific intervention is required, and the patient and their families must be reassured that the condition is benign and usually does not recur.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24419号 / 理博第4918号 / 新制||理||1702(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 前田 啓一, 講師 LEE Shiu Hang, 教授 太田 耕司 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

In recent years, Distributed Generators (DGs) and energy storage devices have gained more popularity due to growing energy and environmental concerns. Interconnection of DGs and storage devices in an electricity grid impacts its performance under steady state and transient conditions. This research aims at analyzing the impacts of distributed generators and energy storage devices on the transient stability of the grid. Battery and ultra-capacitor technologies have been taken as the two types of storage devices and their electrical characteristics have been modeled using Simulink. Impact of these devices has been analyzed by connecting them to the system by means of suitable power electronic converters. The developed methodology has been evaluated using small test systems in MATLAB/Simulink. Transient stability of the test systems has been assessed for different types and locations of faults as well as for different penetration levels of the DGs, with and without the energy storage devices. Impact on the system transient stability has been analyzed based on transient response of the generator rotor speed deviation, rotor angle and terminal voltage of the DGs. Finally, economic analyses have been carried out for different options of DGs, based on wind, diesel and biomass, along with the energy storage devices. Results indicate that the presence of DGs and storage devices enhances the transient stability of the system in most of the cases.

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<p> An existing transient network model for wicked heat pipes was extended to incorporate the effects of axial heat transfer along the wall and wick, heat transfer in the surrounding media, and non-condensable gases in the vapour region. The thermal resistance of the different components was broken down into a larger number of smaller resistances in both axial and radial directions to account for the axial conduction and to handle non-uniform boundary conditions. Two sets of experiments were performed on copper-water wicked heat pipes to evaluate the effect of non-condensable gases, axial conduction, surrounding media and non-uniform boundary conditions. In the first set of experiments, the heat pipes were electrically heated at one end and cooled on the other end using a water jacket. This set of experiments was used to investigate the effect of non-condensable gases, axial conduction and surrounding media on the steady state and transient performance. The effect of the surrounding media was investigated by heating the heat pipe through two different sized aluminum blocks mounted around then heat pipe evaporator section. In the second set of experiments, the effect of using a finned condenser on the steady state performance of the heat pipes were tested in a wind tunnel. The condenser section of the heat pipes in this case was mounted in the test section of the wind tunnel and cooled at different air velocities. Three fin densities were tested along with a heat pipe with no fins. The model predictions of the steady and transient response of the vapour and wall temperature of the heat pipes were in good agreement with the experimental results. </p> <p> The presence of non-condensable gases inside the heat pipe increased the overall thermal resistance of the heat pipe. While the non-condensable gases did not notably affect the transient response during the heat-up phase, it significantly slows down the cool-down phase. The axial conduction through the pipe wall and the wick structure decreases the overall thermal resistance of the heat pipe. The axial conduction did not have a great influence on the time response during the heat-up phase, but was very important in the cooldown phase, especially with the presence of non-condensable gases. The wick structure was found to be the most dominant component in the transient performance of the heat pipe. The evaporator block was the dominant capacitance in the overall conjugate system, and significantly affects the transient response. The experimental results from the finned condenser study showed that the internal resistance increased slightly with the fin density. There was some nonuniformity in the condenser surface temperature at the locations of the fins. However, this non-uniformity did not propagate to other parts of the heat pipe. </p> / Thesis / Master of Applied Science (MASc)

In order to meet demands for faster and more efficient data processing, modern microprocessors are being designed with lower voltage implementations. The processor voltage supply in future generation processors will decrease to 1.1 V ~ 1.8V. More devices will be packed on a single processor chip, and processors will operate at higher frequencies, beyond 1GHz. Therefore, microprocessors need aggressive power management. Future generation processors will draw current up to 50 A ~ 100 A [2]. These demands, in turn, will require special power supplies and Voltage Regulator Modules (VRMs) to provide lower voltages with higher currents and fast transient capabilities for microprocessors. This work presents several low-voltage high-current VRM technologies for future generation data processing, communication, and portable applications. The developed advanced VRMs with these new technologies have advantages over conventional ones in power density, efficiency, transient response, reliability, and cost. The multi-module interleaved quasi-square-wave VRM topology achieves a very fast transient response and a very high power density. This topology significantly reduces the filter inductance and capacitance, while having small output and input ripples. The analysis, design, and experimental verification for this new topology are presented in this work. The current sensing and current sharing techniques are developed with simple and cost-effective implementations. With this technique, traditional current transformers and sensing resistors are not required, and the inductance value, MOSFET on resistance and other parasitics have no effect on current sharing results. The design principles are developed and experimentally verified. A generalized approach and an extension of the novel current sharing control are presented in this work. The techniques for improving VRM light load efficiency are developed in this work. By utilizing the duty cycle signal, VRMs can be implemented with advanced power management functions to reduce further the power consumption at light loads to extend the battery-operation time in portable systems or to facilitate the compliance with various "energy star" ("green" power) requirements in office systems. Four improved approaches are presented and verified with experimental results. The high-input-voltage VRM topology, push-pull forward converter, can be used in high-bus-voltage distributed power systems. This converter has a high efficiency, a high power density, a fast transient response, and can be easily packaged as a standard module. The circuit design and experimental evaluation are addressed to demonstrate the operation principles and advantages of this topology. / Ph. D.

A transient, one-dimensional, model of the membrane of a proton exchange membrane fuel cell is presented. The role of the membrane is to transport protons from the anode to cathode of the fuel cell while preventing the transport of other reactants. The membrane is modeled assuming mono-phase, multi-species flow. For water transport, the principle driving forces modeled are a convective force, an osmotic force (i.e. diffusion), and an electric force. The first of these results from a pressure gradient, the second from a concentration gradient, and the third from the migration of protons from anode to cathode and their effect (drag) on the dipole water molecules. Equations are developed for the conservation of protons and water, the conservation of thermal energy, and the variation of proton potential within the membrane. The model is solved using a fully implicit finite difference approach. Results showing the effects of current density, pressure gradients, water and heat fluxes, and fuel cell start-up on water concentration, temperature, and proton potential across the membrane are presented. / Master of Science