The present study was designed to determine the effect of skin-temperature-biofeedback training on cellular proliferation in three psoriasis patients. It was hypothesized that (a) psoriasis patients would be able to consciously decrease skin temperature of psoriatic tissue, and (b) there would be a positive correlation between rate of cellular proliferation and temperature change. Results obtained indicated biofeedback training to be effective in decreasing the surface temperature of psoriatic tissue. A 2 X 7 analysis of variance for two repeated measures indicated the change in skin temperatures as a function of sample period to be significant, F (6,26) = 3.29, p < .02. Generalization of temperature-training effects from the biofeedback to the no-feedback condition were observed. Rate of proliferation decreased from pretraining to posttraining biopsies.

In this work, initially the radioluminescence (RL) and thermoluminescence (TL) techniques are presented. The radioluminescence is the prompt luminescence emitted by a material under ionizing radiation exposure. The thermoluminescence is the luminescence emitted by a material previously exposed to ionizing radiation when excited by heat. Enegy bands concepts, defects in crystals and the different processes of ionization that take place in matter when exposed to ionizing radiation are briefly discussed in order to present the mechanisms involved in RL and TL processes. The usage of the techniques in characterization of materials and dosimetry is reported, legitimating the importance of the instrument developed. Mechanical and structural parts as well as a description of each component of the instrument are fairly described. The implemented algorithm for controlling the instrument and acquiring data is also discussed. The development of the instrument enabled us to generate temperature ramps with a quite good performance, reaching temperatures up to 500 °C with deviations up to 2 °C, having used heating rates between 0.5 °C/s and 5 °C/s. Calibrations of optical spectrometer used in light collection and irradiation system were carried out. Lastly, TL and RL spectra tests were performed. The RL tests were carried out using several materials which emission spectra are well known by literature, namely, carbon-doped aluminium oxide Al2O3:C, terbium-doped gadolinium oxysulphide Gd2O2S:Tb, europium-doped yttrium oxide Y2O3:Eu and dysprosium-doped calcium borate CaB6O10:Dy. For the TL spectra test, the aluminium oxide doped with carbon Al2O3:C was used. The results of RL and TL spectra tests showed a good agreement with the literature, pointing out that the instrument developed in this work is comparable to others instruments in operation from others research groups, making our results reliable. / Nesse trabalho, inicialmente as técnicas de radioluminescência (RL) e termolumi- nescência (TL) são apresentadas. A radioluminescência é a luminescência imediata emitida por um material quando exposto à radiaçao ionizante. A termoluminescência é a luminescência emitida por um material previamente exposto à radiação quando este é aquecido. Conceitos de bandas de energia, defeitos em cristais e os diferentes processos de ionização que ocorrem na matéria quando exposta à radiação ionizante são brevemente discutidos a fim de apresentar os mecanismos envolvidos na RL e TL. A utilização das técnicas na caracterização de materiais e na dosimetria é reportada, justificando a importância do instrumento desenvolvido. As partes mecânicas/estruturais e uma descrição de cada componente do instrumento são descritos. O algoritmo implementado para controle do instrumento e aquisição de dados é também descrito. O desenvolvimento do instrumento possibilitou a geração de rampas de temperatura com uma boa performance, atingindo até 500 °C com variações de até 2 °C ao utilizar taxas de aquecimento entre 0.5 °C/s e 5 °C/s. Calibrações do espectrômetro óptico utilizado na aquisição da luminescência e do sistema de irradiação foram executadas. Por fim, testes de aquisição de espectros de RL e TL foram realizados. Os testes de RL foram realizados utilizando vários materiais cujos espectros de emissão são bem conhecidos pela literatura, a saber, óxido de alumínio dopado com carbono Al2O3:C , oxisulfeto de gadolínio dopado com térbio Gd2O2S:Tb , óxido de ítrio dopado com európio Y2O3:Eu e borato de cálcio dopado com disprósio CaB6O10:Dy. Para o teste dos espectros de TL, o Al2O3:C foi utilizado. Os resultados dos espectros de RL e TL mostraram concordância com a literatura, indicando que o instrumento desenvolvido é comparável a outros instrumentos em operação de outros grupos, tornando os nossos resultados confiáveis.

The function of wireless sensor networks is to monitor events or gather information and report the information to a sink node, a central location or a base station. It is a requirement that the information is transmitted through the network efficiently. Wireless communication is the main activity that consumes energy in wireless sensor networks through idle listening, overhearing, interference and collision. It becomes essential to limit energy usage while maintaining communication between the sensor nodes and the sink node as the nodes die after the battery has been exhausted. Thus, conserving energy in a wireless sensor network is of utmost importance. Numerous methods to decrease energy expenditure and extend the lifetime of the network have been proposed. Researchers have devised methods to efficiently utilise the limited energy available for wireless sensor networks by optimising the design parameters and protocols. Cross-layer optimisation is an approach that has been employed to improve wireless communication. The essence of cross-layer scheme is to optimise the exchange and control of data between two or more layers to improve efficiency. The number of transmissions is therefore a vital element in evaluating overall energy usage. In this dissertation, a Markov Chain model was employed to analyse the tuning of two layers of the protocol stack, namely the Physical Layer (PHY) and Media Access Control layer (MAC), to find possible energy gains. The study was conducted utilising the IEEE 802.11 channel, SensorMAC (SMAC) and Slotted-Aloha (S-Aloha) medium access protocols in a star topology Wireless Temperature Sensor Network (WTSN). The research explored the prospective energy gains that could be realised through optimizing the Forward Error Correction (FEC) rate. Different Reed Solomon codes were analysed to explore the effect of protocol tuning on energy efficiency, namely transmission power, modulation method, and channel access. The case where no FEC code was used and analysed as the control condition. A MATLAB simulation model was used to identify the statistics of collisions, overall packets transmitted, as well as the total number of slots used during the transmission phase. The bit error probability results computed analytically were utilised in the simulation model to measure the probability of successful transmitting data in the physical layer. The analytical values and the simulation results were compared to corroborate the correctness of the models. The results indicate that energy gains can be accomplished by the suggested layer tuning approach. / Electrical and Mining Engineering / M. Tech. (Electrical Engineering)

Thesis. 1975. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / Bibliography: leaves 194-195. / by Richard James Casler, Jr. / M.S.

This work offers new computational methods for the optimal control of the conjugate heat transfer (CHT) problem in thermal science. Conjugate heat transfer has many important industrial applications, such as heat exchange processes in power plants and cooling in electronic packaging industry, and has been a staple of computational methods in thermal science for many years. This work considers the Dirichlet boundary control of fluid-solid CHT problems. The CHT system falls into the category of multi-physics problems. Its domain typically consists of two parts, namely, a solid region subject to thermal heating or cooling and a conjugate fluid region responsible for thermal convection transport. These two different physical systems are strongly coupled through the thermal boundary condition at the fluid-solid interface. The objective in the CHT boundary control problem is to select optimally the fluid inflow profile that minimizes an objective function that involves the sum of the mismatch between the temperature distribution in the system and a prescribed temperature profile and the cost of the control. This objective is realized by minimizing a nonlinear objective function of the boundary control and the fluid temperature variables, subject to partial differential equations (PDE) constraints governed by the coupled heat diffusion equation in the solid region and mass, momentum and energy conservation equations in the fluid region. Although CHT has received extensive attention as a forward problem, the optimal Dirichlet velocity boundary control for the coupled CHT process to our knowledge is only very sparsely studied analytically or computationally in the literature [131]. Therefore, in Part I, we describe the formulation of the optimal control problem and introduce the building blocks for the finite element modeling of the CHT problem, namely, the diffusion equation for the solid temperature, the convection-diffusion equation for the fluid temperature, the incompressible viscous Navier-Stokes equations for the fluid velocity and pressure, and the model verification of CHT simulations. In Part II, we provide theoretical analysis to explain the nonsmoothness issue which has been observed in this study and in Dirichlet boundary control of Navier-Stokes flows by other scientists. Based on these findings, we use either explicit or implicit numerical smoothing to resolve the nonsmoothness issue. Moreover, we use the numerical continuation on regularization parameters to alleviate the difficulty of locating the global minimum in one shot for highly nonlinear optimization problems even when the initial guess is far from optimal. Two suites of numerical experiments have been provided to demonstrate the feasibility, effectiveness and robustness of the optimization scheme. In Part III, we demonstrate the strategy of achieving parallel scalable algorithms for CHT models in Simulations of Reactor Thermal Hydraulics. Our motivation originates from the observation that parallel processing is necessary for optimal control problems of very large scale, when the simulation of the underlying physics (or PDE constraints) involves millions or billions of degrees of freedom. To achieve the overall scalability of optimal control problems governed by PDE constraints, scalable components that resolve the PDE constraints and their adjoints are the key. In this Part, first we provide the strategy of designing parallel scalable solvers for each building blocks of the CHT modeling, namely, for the discrete diffusive operator, the discrete convection-diffusion operator, and the discrete Navier-Stokes operator. Second, we demonstrate a pair of effective, robust, parallel, and scalable solvers built with collaborators for simulations of reactor thermal hydraulics. Finally, in the the section of future work, we outline the roadmap of parallel and scalable solutions for Dirichlet boundary control of fluid-solid conjugate heat transfer processes.

Este trabalho aborda o desenvolvimento de um sistema de controle de temperatura para um aquecedor de passagem de água a gás. O sistema de controle Controlgás é apresentado e comparado ao sistema de controle típico, usado em aquecedores de passagem convencionais. São apresentadas as características e objetivos do projeto Controlgás, o qual serviu de base para o desenvolvimento deste trabalho. É apresentada uma fundamentação teórica sobre técnicas de controle para compensação de variações paramétricas e de atrasos de transporte, bem como uma revisão sobre as principais soluções já desenvolvidas para o controle de temperatura da água em aquecedores de passagem. A bancada experimental, contendo o aquecedor e o sistema de controle, utilizada em trabalhos anteriores, foi reestruturada e instrumentada com sensores de temperatura na entrada e na saída de água e com sensores que detectam a presença de chama e de fluxo de água. Foi desenvolvida uma servo-válvula que permite a regulagem automática da vazão de gás. Desenvolveu-se um circuito de potência para o acionamento dos atuadores (solenoides e servo-válvula) da bancada, assim como algoritmos que geram os sinais adequados para seu funcionamento. Foi feita a identificação do processo e o modelo da servo-válvula foi obtido por meio da análise de ensaios experimentais. O modelo do sistema completo foi desenvolvido no programa Simulink, onde foram feitas simulações do comportamento dinâmico do sistema proposto. O sistema foi implantado experimentalmente e foi capaz de convergir para as temperaturas de referência durante os ensaios. / This work addresses the development of a temperature control system for a gas tankless water heater. The Controlgás control system is presented and compared to typical control systems used in regular tankless water heaters. The characteristics and objectives of Controlgás project, which formed the basis for the development of this work, are presented. A theoretical foundation on control techniques for compensation of parametric variations and transport delays is presented, as well as a review of the main solutions already developed for the control of water temperature on tankless water heaters. The experimental set containing the heater and the control system used in previous work was restructured and instrumented with temperature sensors at the water's input and output and with sensors which detect the presence of flame and the water flow. A servo-valve that allows automatic adjustment of the gas flow was developed. A power circuit was created to drive the actuators (solenoids and servo-valve) of the set, as well as algorithms that generate the appropriate signals for its operation. The process identification and the servo-valve‟s model were obtained through experimental analysis. The system‟s complete model was developed in Simulink, where simulations of the dynamic behavior of the proposed system were made. The system was implemented experimentally and was able to converge to the reference temperatures during the tests.

Prostate cancer is the most prevalent cancer and the third-leading cause of cancer-related death among men in the developed world, with the number of cases expected to double within the next 15 years. Conventional therapies offer good control of local disease but are associated with high complication rates reducing long-term health-related quality-of-life significantly. MRI-guided transurethral ultrasound therapy has emerged as an attractive, minimally-invasive alternative for the treatment of localized prostate cancer, where the entire gland is heated to temperatures sufficient to cause irreversible thermal coagulation. A device inserted in the urethra uses multiple ultrasound transducers to produce directional heating patterns directly in the prostate. Adjusting the ultrasound power, frequency and device rotation rate enables high spatial control of the thermal lesion. MRI provides information essential to the accurate targeting of the prostate; anatomical images for device positioning and treatment planning, and quantitative temperature measurements within the prostate to compensate for dynamic tissue changes, using feedback control. This thesis develops a complete treatment delivery strategy for producing conformal regions of thermal coagulation shaped to whole-gland prostate volumes, while limiting the thermal impact to the surrounding important anatomy. First, acoustic and thermal simulations incorporating a novel temperature feedback controller were used to model and shape regions of coagulation to human prostate geometries with a high degree of accuracy. Second, treatment delivery strategies were developed and simulated to reduce thermal injury to the surrounding anatomy, below the threshold for sustained damage. Third, experiments in tissue-mimicking gel phantoms confirmed the predictive accuracy of the simulations and the feasibility of producing conformal volumes of coagulation using transurethral ultrasound devices and MRI-temperature feedback. This work forms the basis of clinical treatment delivery methods and supports the use of the simulations as a planning tool to enhance the inherent compromise between safety and efficacy on a patient-specific basis.

Prostate cancer is the most prevalent cancer and the third-leading cause of cancer-related death among men in the developed world, with the number of cases expected to double within the next 15 years. Conventional therapies offer good control of local disease but are associated with high complication rates reducing long-term health-related quality-of-life significantly. MRI-guided transurethral ultrasound therapy has emerged as an attractive, minimally-invasive alternative for the treatment of localized prostate cancer, where the entire gland is heated to temperatures sufficient to cause irreversible thermal coagulation. A device inserted in the urethra uses multiple ultrasound transducers to produce directional heating patterns directly in the prostate. Adjusting the ultrasound power, frequency and device rotation rate enables high spatial control of the thermal lesion. MRI provides information essential to the accurate targeting of the prostate; anatomical images for device positioning and treatment planning, and quantitative temperature measurements within the prostate to compensate for dynamic tissue changes, using feedback control. This thesis develops a complete treatment delivery strategy for producing conformal regions of thermal coagulation shaped to whole-gland prostate volumes, while limiting the thermal impact to the surrounding important anatomy. First, acoustic and thermal simulations incorporating a novel temperature feedback controller were used to model and shape regions of coagulation to human prostate geometries with a high degree of accuracy. Second, treatment delivery strategies were developed and simulated to reduce thermal injury to the surrounding anatomy, below the threshold for sustained damage. Third, experiments in tissue-mimicking gel phantoms confirmed the predictive accuracy of the simulations and the feasibility of producing conformal volumes of coagulation using transurethral ultrasound devices and MRI-temperature feedback. This work forms the basis of clinical treatment delivery methods and supports the use of the simulations as a planning tool to enhance the inherent compromise between safety and efficacy on a patient-specific basis.

The main contribution of this dissertation is the demonstration of the impact of a new emerging technology called 3D-integration technology on conventional high-performance microprocessors. 3D-integration technology stacks active devices in the vertical dimension in addition to the conventional horizontal dimension. The additional degree of connectivity in the vertical dimension enables circuit designers to replace long horizontal wires with short vertical interconnects, thus reducing delay, power consumption, and area. To adapt planar microarchitectures to 3D-integrated designs, we study several building blocks that together comprise a substantial portion of a processor s total transistor count. In particular, we focus our attention on three basic circuit classes: static random access memory (SRAM) circuits, associative/CAM logic circuits, and data processing in conventional high-performance processors. We propose 2-die-stacked and 4-die-stacked 3D-integrated circuits to deal with the constraints of the conventional planar technology. We propose high-performance 3D-integrated microprocessors and evaluate the impact on performance, power, and temperature. We demonstrate two different approaches to improve performance: clock speed (3D-integrated processors with identical microarchitectural configurations as the corresponding planar processor run at a higher clock frequency), and IPC (3D-integrated processors accommodate larger-sized modules than the planar processors for the same frequency). We demonstrate the simultaneous benefits of the 3D-integration and highlight the power density and thermal issues related to the 3D-integration technology. Next, we propose microarchitectural techniques based on significance partitioning and data-width locality to effectively address the challenges of power density and temperature. We demonstrate that our microarchitecture-level techniques can effectively control the power density issues in the 3D-integrated processors. The 3D-integrated processors provide a significant performance benefit over the planar processors while simultaneously reducing the total power. The simultaneous benefits in multiple objectives make 3D-integration a highly desirable technology for use in building future microprocessors. One of the key contributions of this dissertation is the temperature analysis that shows that the worst-case temperatures on the 3D-integrated processors can be effectively controlled using microarchitecture level techniques. The 3D-integration technology may extend the applicability of Moore s law for a few more technology generations.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves [217]-221). Also available on the Internet.