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Patch antennas are fundamental elements in many microwave communications systems. However, patch antennas receive/transmit signals over a very narrow bandwidth (typically a maximum of 3% bandwidth). Design modifications directed toward bandwidth expansion generally yield 10% to 40% bandwidth. The series varactor tuned patch antenna configuration was the bandwidth enhancement method explored in this research; this configuration is implemented by dividing a patch antenna into multiple sections and placing varactors across the resultant gaps. In addition to yielding a large bandwidth, the configuration has a number of ancillary benefits, including straightforward integration and design flexibility. Through the research represented by this work, the properties of the series varactor tuned patch antenna, herein referred to as the Fragmented Patch Antenna (or FPA), were explored and optimized. As a result, an innovative patch antenna was produced that yielded 63.4% frequency tuning bandwidth and covered a frequency range between 2.8 and 5.4 GHz. The wide bandwidth was achieved through a detailed parametric study. The products of this study were the discovery of multiple tuning resonances that were used to expand the tuning bandwidth and the understanding/documentation of the significance of specific antenna dimensions. Measurement results were obtained through the fabrication of a prototype antenna using semiconductor varactors. In the second research phase, the construction of capacitors using the tunable permittivity material Barium Strontium Titanate (BST) was investigated. Using this material in conjunction with nano-fabrication techniques, varactors were developed that had good estimated performance characteristics and were considered appropriate for integration into adaptive microwave circuitry, such as the tunable antenna system. The varactors were constructed by using Focused Ion Beam (FIB) milling to create a nano-scale capacitive gap in a transmission line. A combination of end-point current detection (EPD) and cross-section scanning electron (SEM) and ion beam (FIB) microscope images were used to optimize the milling procedure. The future extensions of this work include the integration of the BST varactors with the antenna design; the configuration of the developed BST varactors lends itself to a straightforward integration with the FPA antenna.

Global planarization is one of the major demands of the semiconductor industry. Chemical mechanical polishing (CMP) is the planarization method of choice use to achieve the required stringent tolerances essential for successful fabrication of next generation Integrated Circuits (IC). The predominant reason for CMP defects is the shear and normal stresses during polishing to which the material is subjected. Understanding the process of CMP and factor that contribute to overall stress addition during polishing requires an approach that encompasses all the four major categories of variables, namely: a) machine parameters, b) material properties, c) polishing pad characteristics, and d) polishing slurry performance. In this research, we studied the utilized in-situ technique involving acoustic emission (AE) signal monitoring and coefficient of friction (COF) monitoring using a CETRTM Bench Top CMP Tester to evaluate the impact of variation in machine parameters on the CMP process. The mechanical and tribological properties of different candidate materials have been evaluated bring potential challenges in their integration to the fore. The study also involves destructive and non destructive testing of polishing pads performed for characterization and optimization of polishing pad architecture. Finally, the investigation concludes proposing novel nanoparticle CMP slurry which has a predominant chemical component in its polishing mechanism. It was found that the decrease in the mechanical shear and normal loading by: a) operating the process in the low stress regime, b) using potential materials that are mechanically stronger, c) using polishing pads with lesser variation in specific gravity and with a surface that is has its mechanical properties fine tuned to those of the wafer, and d) deploying polishing slurry with a significant chemical component mechanical removal, are some of the approaches that can be employed to meet the future challenges of the CMP process and reduce the defect associated with it.

A Mandarin phrase recognition system based on MFCC, LPC scaled excitation, vowel model, hidden Markov model (HMM) and Viterbi algorithm is proposed in this thesis. HMM, which is broadly used in speech recognition at present, is adopted in the main structure of recognition. In order to speed up the recognition time, we take advantage of stability of vowels in Mandarin and incorporate with vowel class recognition in our system. For the speaker-dependent case, a single Mandarin phrase recognition can be accomplished within 1 seconds on average in the laboratory environment.

Online process monitoring and feedback control are two widely researched aspects that can impact the performance of a myriad of process applications. Semiconductor manufacturing is one such application that due to the ever increasing demands placed on its quality and speed holds tremendous potentials for further research and development in the areas of monitoring and control. One of the key areas of semiconductor manufacturing that has received significant attention among researchers and practitioners in recent years is the online sensor based monitoring and feedback control of its nanoscale wafer fabrication process. Monitoring and feedback control strategies of nanomanufacturing processes often require a combination of monitoring using nonstationary and multiscale signals, and a robust feedback control using complex process models. It is also essential for the monitoring and feedback control strategies to possess stringent properties such as high speed of execution, low cost of operation, ease of implementation, high accuracy, and capability for online implementation. Due to the above requirement, a need is being felt to develop state-of-the-art sensor data processing algorithms that can perform far superior to those that are currently available both in the literature and commercially in the form of softwares.The contributions of this dissertation are three fold. It first focuses on the development of an efficient online scheme for process monitoring. The scheme combines the potentials of wavelet based multiresolution analysis and sequential probability ratio test to develop a very sensitive strategy to detect changes in nonstationary signals. Secondly, the dissertation presents a novel online feedback control scheme. The control problem is cast in the framework of probabilistic dynamic decision making, and the control scheme is built on the mathematical foundations of wavelet based multiresolution analysis, dynamic programming, and machine learning. Analysis of convergence of the control scheme is also presented. Finally, the monitoring and the control schemes are tested on a nanoscale manufacturing process (chemical mechanical planarization, CMP) used in silicon wafer fabrication. The results obtained from experimental data clearly indicate that the approaches developed outperform the existing approaches. The novelty of the research in this dissertation stems from the fact that they further the science of sensor based process monitoring and control by uniting sophisticated concepts from signal processing, statistics, stochastic processes, and artificial intelligence, and yet remain versatile to many real world process applications.

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Submitted by Maike Costa (maiksebas@gmail.com) on 2017-06-21T14:26:33Z No. of bitstreams: 1 arquivototal.pdf: 3690977 bytes, checksum: 752560aa5c7d78968c32cb55f0778788 (MD5) / Made available in DSpace on 2017-06-21T14:26:33Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3690977 bytes, checksum: 752560aa5c7d78968c32cb55f0778788 (MD5) Previous issue date: 2016-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Total hardness and Total alkalinity are important physico-chemical parameters for the evaluation of water quality and are determined by volumetric analytical methods. These methods have difficult to detect the endpoint of the titration due to the difficult of viewing the color transition inherent to each of them. To circumvent this problem, here is proposed a new automatic method for the detection of the titration end point for the determination of total hardness and total alkalinity in mineral water samples. The proposed flow-batch titrator consists of a peristaltic pump, five three-way solenoid valves, a magnetic stirrer, an electronic actuator, an Arduino MEGA 2560TM board, a mixing chamber and a webcam. The webcam records the digital movie (DM) during the addition of the titrant towards mixing chamber, also recording the color variations resulting from chemical reactions between titrant and sample within chamber. While the DM is recorded, it is decompiled into frames ordered sequentially at a constant rate of 30 frames per second (FPS). The first frame is used as a reference to define the region of interest (RI) of 48 × 50 pixels and the R channel values, which are used to calculate the Pearson's correlation coefficient (r) values. r is calculated between the R values of the initial frame and each subsequent frame. The titration curves are plotted in real time using the values of r (ordinate axis) and the total opening time of the valve titrant (abscissa axis). The end point is estimated by the second derivative method. A software written in ActionScript 3.0 language manages all analytical steps and data treatment in real time. The feasibility of the method was attested by its application for the analysis of natural water samples. Results were compared with classical titration and did not present statistically significant differences when the paired ttest at the 95% confidence level was applied. The proposed method is able to process about 71 samples per hour, and its precision was confirmed by overall relative standard deviation (RSD) values, always lower than the 2,4% for total hardness and 1,4% for total alkalinity. / A dureza total e a alcalinidade total são importantes parâmetros físico-químicos para avaliação da qualidade de águas e são determinados por métodos volumétricos de análise. Estes métodos apresentam difícil detecção do ponto final da titulação devido à dificuldade de visualização das transições de cores inerentes a cada um deles. Para contornar este problema, foi proposta neste trabalho uma nova metodologia automática para a detecção do ponto final nas determinações de dureza total e alcalinidade total em águas. O titulador em fluxo-batelada proposto é composto de uma bomba peristáltica, cinco válvulas solenoides de três vias, um agitador magnético, um acionador de válvulas, uma placa Arduíno MEGA 2560TM, uma câmara de mistura e uma webcam. O programa de gerenciamento e controle do titulador foi escrito em linguagem ActionScript 3.0. A webcam grava o filme digital durante a adição do titulante na câmara de mistura, registrando as variações de cor decorrentes das reações químicas entre titulante e amostra no interior de câmara. Enquanto o filme é gravado, este é decomposto em quadros ordenados sequencialmente a uma taxa constante de 30 quadros por segundo (FPS). O primeiro quadro é utilizado como referência para definir uma região de interesse (RI) com 48 x 50 pixels, na qual seus valores R, G e B são utilizados para calcular os valores de coeficiente de correlação de Pearson (r). O valor de r é calculado entre os valores de R do quadro inicial e de cada quadro subsequente. As curvas de titulação são obtidas em tempo real usando os valores de r (ordenadas) e o tempo total de abertura da válvula de titulante (abscissas). O ponto final é estimado pelo método de segunda derivada. O método foi aplicado na análise de águas minerais e os resultados foram comparados com a titulação clássica, não apresentando diferenças estatisticamente significativas com aplicação do teste t pareado a 95% de confiança. O método proposto foi capaz de processar até 71 amostras por hora e a sua precisão foi confirmada pelos valores de desvio padrão relativos (DPR) globais, sempre inferiores as 2,4% para dureza total e 1,4% para alcalinidade total.

I have decided to deal with the issue of "Risk Sources of Ammonia Cooling Systems and Their Eventual Accidental Impacts" as the risk of leakage from the cooling systems using ammonia as a coolant still prevails these days. Eventual accidental leakage simulation models were applied to several winter stadiums using ammonia as a coolant. Based on these results, it has been assessed how dangerous these sources for the citizens living in their surroundings are and measures to increase safety were suggested, too.

Orientador: Wei-Liang Qian / Resumo: Uma característica vital da cromodinâmica quântica (QCD) está relacionada à simetria quiral. Isso é particularmente intrigante devido ao papel crítico da simetria quiral não abeliana dos spinores de Lorentz na física teórica moderna. Muitos esforços teóricos foram dedicados à sua quebra espontânea no vácuo, bem como a restauração da mesma no ambiente extremamente quente ou denso. Além disso, quarks e glúons tornam-se os graus de liberdade relevantes por meio da transição de desconfinamento do estado dos hádrons. O significado desta última está intimamente ligado às implicações da equação de Callan-Symanzik e à teoria do grupo renormalizado. No entanto, em princípio, ambas as transições acima podem ser descritas pela QCD. Os estudos da QCD na rede demonstraram que a transição do sistema é um cruzamento suave com a densidade bariônica nula e a massa de quarks estranhos grandes. No potencial químico finito, por outro lado, uma variedade de modelos prevê a ocorrência de uma transição de fase de primeira ordem entre a fase hadrônica e o plasma de quarks e glúons (QGP). Esses resultados indicam que um ponto crítico (CEP) pode estar localizado em algum lugar no diagrama de fases da QCD no qual a linha de transições de fase de primeira ordem termina. Espera-se que a transição seja de segunda ordem neste caso. De fato, entre outros objetivos estabelecidos, o programa Beam Energy Scan (BES) em andamento no Relativistic Heavy Ion Collider (RHIC) é impulsionado pela busca do CEP. Nesta t... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: One vital characteristic of the quantum chromodynamics (QCD) is regarding the chiral symmetry. This is particularly intriguing owing to the critical role of non-abelian gauge symmetry of Lorentz spinors in modern theoretical physics. Many theoretical efforts have been devoted concerning its spontaneously breaking in the vacuum, as well as the restoration at the extremely hot or dense environment. Furthermore, quarks and gluons become the relevant degrees of freedom through the deconfinement transition from the hadron state of matter. The significance of the latter is closely connected to the implications of the Callan-Symanzik equation and the theory of the renormalized group. Nonetheless, in principle, both of the above transitions can be described by the QCD. Lattice QCD studies demonstrated that the transition of the system is a smooth crossover at vanishing baryon density and large strange quark mass. At finite chemical potential, on the other hand, a variety of models predict the occurrence of a first-order transition between the hadronic phase and quark-gluon plasma (QGP). These results indicate that a critical endpoint (CEP) might be located somewhere on the QCD phase diagram at which the line of first-order phase transitions terminates. The transition is expected to be of second-order at this point. As a matter of fact, among other established goals, the ongoing Beam Energy Scan (BES) program at the Relativistic Heavy Ion Collider (RHIC) is driven by the search for th... (Complete abstract click electronic access below) / Doutor

We have studied aspirin as a potential chemopreventive for colorectal cancer, completing Phase I studies on aspirin pharmacology and potential biomarker assays (prostaglandins, PGE2 and PGF(2α) and cyclooxygenase modulation) in normal human subjects. These studies have determined the optimal dose of aspirin for future Phase IIa and IIb chemopreventive trials in high-risk cohorts of patients for colon cancer. Aspirin's effects on rectal prostaglandins are prolonged, detectable even after aspirin and its metabolite are removed from the plasma. Aspirin-mediated inhibition of prostaglandin production in the human rectal epithelium may be related to direct suppression of cyclooxygenase transcription and not to enzyme inactivation by acetylation. A systematic method to monitor adherence (self- report, telephone contact, pill count, and microelectronic monitoring) has been established for future trials. Strategies to improve recruitment of high-risk cohorts have been developed. Phase IIa non-randomized studies with aspirin at 81 mg in high-risk cohorts (resected Duke's A colon cancer, Duke's C colon cancer treated with adjuvant therapy and disease-free at 5 years, history of colon adenomas > 1 cm, two or more first-degree relatives with colon cancer, and familial adenomatous polyposis and hereditary non-polyposis colorectal cancer syndromes) are currently being conducted for surrogate end- point biomarker (prostaglandins, cyclooxygenase, cellular mucins, and proliferation) modulation.