This work consists of two main parts: i) Design and implementation of a compact current-reusing 2.4GHz direct-modulation transmitter with on-chip automatic tuning; ii) Design and implementation of a novel highly-reconfigurable, continuously tunable, power-adjustable Active-RC filter for multiple standards. The design, analysis, and experimental verification of a proposed self-calibrating, current reused 2.4GHz, direct-modulation transmitter are introduced. A stacked arrangement of the power amplifier/voltage-controlled oscillator is presented along with a novel LC-tank-tuning algorithm with a simple, low-cost, on-chip implementation. To transmit maximum power, the tuning loop ensures the PA's resonant tank is centered around the operating frequency, and the loop requires no ADC, DSP, or external signal generator. This work also details the proposed tuning-loop algorithm and examines the frequency-dependent nonlinear power-detector. The system was implemented in TSMC 0.18[mu]m CMOS, occupies 0.7 mm² (TX) + 0.1 mm² (self tuning), and was measured in a QFN48 package on FR4 PCB. Automatically adjusting the tank-tuning bits within their tuning range results in >4dB increase in output power. With the self-tuning circuit active, the transmitter delivers a measured output power of > 0dBm to a 100-[omega] differential load, and the system consumes 22.9 mA from a 2.2-V supply. A biquad design methodology and a baseband low-pass filter is presented for wireless and wireline applications with reconfigurable frequency response, selectable order (1st/3rd/5th), continuously tunable cutoff frequency (1MHz-20MHz) and adjustable power consumption (3mW-7.5mW). A discrete capacitor array coarsely tunes the low-pass filter, and a novel Continuous Impedance Multiplier (CIM) then finely tunes the filter. Resistive/capacitive networks select between the Chebyshev and Inverse Chebyshev approximation types. Also, a new stability metric for biquads, Minimum Acceptable Phase Margin (MAPM), is presented and discussed in the context of filter compensation and passband ripple considerations. Experimental results yield an IIP3 of 31.3dBm, a THD of -40dB at 447mV[subscript pk, diff] input signal amplitude, and a DR of 71.4dB. The filters tunable range covers frequencies from 1MHz to 20MHz. In Inverse Chebyshev mode, the filter achieves a passband group delay variation less than ±2:5%. The design is fabricated in 0.13[mu]m CMOS, occupies 1.53mm², and operates from a 1-V supply.

Acoustic plane wave intearctions with a rough seabed with a continuously varying density and sound speed in a fluid-like sediment layer overlying an elastic basement is considered in this thesis. The acoustic properties in the sediment layer possess an exponential type of variation in density and one of the three classes of sound speed profiles, which are constant, k^2-linear, or inverse-square variations. Analytical solutions for the Helmholtz equation in the sediment layer, combined with a formulation based upon boundary perturbation theory, facilitate numerical implementation for the solution of coherent field. The coherent reflection coefficients corresponding to the aformentioned density and sound speed profiles for various frequencies, roughness parameters, basement stiffness, are numerically generated and analyzed. Physical interpretations are provided for various results. This simple model characterizes three important features of an realistic sea floor, including seabed roughness, sediment inhomogenieties, and basement shear property,%Two dimensions is considered in the seafloor environment and the random roughness is belong to one dimension space.% , therefore, provides a canonical model for the study of seabed acoustics. The variation of the acoustic properties takes such a form that it is not only geologically realistic, but also renders analytical solutions for the Helmholtz equation, thus facilitating the formulation of the problem. The computational algorithm for the spatial spectrum of the scattered field due to random seabed has been developed based upon a boundary perturbation method. %About scattering field, only one time reflection from the sediment is taked account of, because the higher numerical order is, the lower scattering energy exist.% The results have shown that, while the coherent field mainly depends upon the gross structure of the rough seabed represented by the RMS roughness, the scattered field heavily depends upon the details of the roughness structure specialized by the roughness power spectrum and the spatial correlation length of the rough surface. The dependence of the spatial spectrum on the sediment stratification is also carefully examined.

Tyrimo objektas – didelio meistriškumo rankininkių kvėpavimo sistemos funkcija ir aerobinis pajėgumas. Tyrimo aktualumas. Aerobinis pajėgumas yra labai svarbus rankinyje siekiant aukštų sportinių rezultatų. Kiekvienoje sporto šakoje sportininkai skiriasi savo aerobiniu pajėgumu, todėl mūsų darbas yra aktualus, nes informatyviais tyrimo metodais nustatėme skirtingo amžiaus rankininkių aerobinį pajėgumą ir kvėpavimo sistemos funkcinius rodiklius. Tyrimo problema. Kokią įtaką amžius turi rankininkių aerobiniam pajėgumui bei kvėpavimo sistemos funkcijoms? Tyrimo tikslas: Nustatyti skirtingo amžiaus rankininkių kvėpavimo funkcijos ir aerobinio pajėgumo ypatumus. Uždaviniai: 1. Nustatyti skirtingo amžiaus rankininkių kvėpavimo sistemos pajėgumą ramybėje ir nuosekliai didėjančio fizinio krūvio metu. 2. Nustatyti skirtingo amžiaus rankininkių aerobinį pajėgumą. 3. Palyginti jaunesnio ir vyresnio amžiaus rankininkių aerobinį pajėgumą ir kvėpavimo funkcinius rodiklius. Išvados 1. Jaunesniųjų rankininkių maksimalūs plaučių ventiliacijos rodikliai buvo didesni, tiek testuojant ramybėje (maksimali valinga ventiliacija), tiek ir nuosekliai greitėjančio bėgimo metu (didžiausios pasiektos reikšmės). 2. Absoliučios plaučių talpos reikšmingai nesiskyrė lyginant skirtingo amžiaus rankininkių, tačiau lyginant su atitinkamo amžiaus norminėmis reikšmėmis forsuota iškvėpimo talpa buvo santykinai geresnė vyresnių rankininkių. 3. Jaunesnių rankininkių maksimalus deguonies suvartojimas... [toliau žr. visą tekstą] / The object of research – respiratory system and aerobic capacity of professional female handball players. The relevance of research. The efficiency of aerobic capacity is important in handball play. In every sports athletes differs in aerobic theme capacity, thats why our study is relevant, because we obtained the results about on aerobic capacity of the female handball players in different age group. Question of research – what influence has age for the aerobic capacity and respiratory system function of female handball players. The purpose of research: to determine the respiratory function and aerobic capacity of the professional female handball players of different age. Goals: 1. To determine the capacity of respiratory system of the female handball players. 2. To determine the aerobic capacity of female handball players. 3. To compare the data of senior and junior female hanball players. Conclusions 1. The rates of the maximal lungs ventilation of junior female handball players were greater in both while testing at rest and maximal ventilation continuously accelerating running (maximal achieved value). 2. Absolute lungs capacity did not change significantly between different age female handball players, although comparing the forced exhalation capacity of appropriate age standard value, senior handball players had relatively better data. 3. The maximal oxygen uptake, ventilation threshold and correspondent values of vegetative system (HR, maximal oxygen... [to full text]

Purpose: The purpose of this study is to explore organizational identity as a potential process.   Design/Methodology/Approach: We applied a qualitative method and followed an inductive approach that was applied to a multiple-in-depth-case study for which we conducted semi-structured interviews with 26 members of two organizations, the Swedish consulting company REACH and the Swiss digital agency WONDROUS. Following a narrative approach, both for structuring the empirical findings, as well as conducting the analysis, we used over 16 hours of interviews to create company narratives and subsequently analyzed them in multiple steps in the fashion of a narrative analysis.   Findings: Based on our empirical findings and the empirical analysis, we developed a conceptualization, the Flux Model. We contribute to the existing body of literature by proposing that the Flux Model visualizes the dynamics of how organizational members socially construct organizational identity on the premise of their own (self-)perceptions. By presenting the different parts of the model and their multiple layers, the process of how organizational identity is continuously becoming is illustrated.   Research Limitations/Implications: The scope of our study is restricted to the two case companies in question. If our abstractions from the cases in form of the Flux Model help to better understand the process of organizing, managers become liberated to make deliberate choices about their organizations’ identities. For research this means an even tighter connection to individual psychology and a deepening of the perspective that organizational identity can not only be viewed as something companies have.   Originality/Value: Out of skepticism towards the usefulness of viewing organizational identity as a process, we applied a symbolic interpretivist perspective and allowed for the possibility that we might not find a process after all. The primary value of this study we believe to be found in the extensive presentation of empirical data, together with our narrative analysis and our conceptual contribution (the Flux Model).

Os primeiros estudos sobre pavimentos de concreto continuamente armados (PCCA) foram desenvolvidos em zonas cujo clima característico é o temperado (EUA, Holanda e Bélgica), não se tendo estudos técnicos acerca do comportamento do pavimento em ambiente tropical. A premissa de funcionamento do PCCA está baseada na não execução de juntas de retração, obrigatórias em pavimentos de concreto simples (PCS), ou seja, as fissuras devido à retração do concreto ocorrem aleatoriamente, sendo controladas pela elevada taxa de armadura longitudinal disposta longitudinalmente ao longo de toda a extensão do pavimento. Como essa armadura não possui função estrutural, pois é colocada acima da linha neutra da placa, no banzo comprimido, sua função é manter as fissuras fortemente apertadas, garantindo suavidade ao rolamento e elevada transferência de carga (LTE), a qual ocorre pelo intertravamento dos agregados nas faces fissuradas, proporcionando assim um pavimento de alta durabilidade e que dispende baixíssimos custos com manutenção. No Brasil, a primeira experiência com PCCA teve início no ano de 2010, quando foram construídas quatro seções de 50 m de extensão cada, consideradas curtas em comparação aos 400 m de extensão de um PCCA rodoviário que podem ser alcançados ao final de um dia de trabalho. O monitoramento contínuo de tais seções mostrou haver uma diferença muito significativa de comportamento, comparado aos PCCA tradicionais, no que tange o tempo decorrido para estabelecimento do padrão de fissuração (a primeira fissura surgiu um ano após a construção), bem como espaçamento médio entre as fissuras, devido à curta extensão das placas e a inexistência de um sistema de ancoragem nas extremidades. Assim, para melhor compreender o comportamento de pavimentos de concreto com armadura contínua com padrões condizentes à realidade rodoviária em ambiente tropical, em janeiro de 2016, foi construído no campus da Universidade de São Paulo o primeiro PCCA de longa extensão do Brasil, com 200 m de comprimento. Foram empregados quatro diferentes tipos de concreto, variando o tipo de cimento e o tipo de agregado, bem como foram empregados aço galvanizado e aço comum. Para entender o comportamento do pavimento sob as condições climáticas brasileiras foram realizados três estudos: levantamento de fissuras (espaçamento e abertura), modelagem analítica do espaçamento entre fissuras através de modelos de previsão de retração em concreto e testes com FWD para avaliação da eficiência de transferência de carga (LTE) entre as fissuras. A análise do padrão de fissuração mostrou que o desenvolvimento das fissuras aconteceu conforme a literatura técnica, tendo início na primeira semana após a concretagem e atingindo aproximadamente 60% do número total de fissuras antes do primeiro mês. As seções centrais possuem o maior número de fissuras, pois estão ancoradas pelas seções de extremidade, onde o surgimento das fissuras é mais lento por conta da falta de ancoragem. As aberturas das fissuras mostraram-se maiores nas posições com aço galvanizado devido à menor aderência aço-concreto nesse caso, em comparação às posições com aço comum. O modelo de previsão de retração no concreto que melhor se aproximou do espaçamento médio desenvolvido em campo foi o modelo do Eurocode 2, com diferenças em torno de 30%, aproximadamente. As análises de LTE mostraram um desempenho muito satisfatório, apesar de a LTE nas regiões com aço galvanizado ter resultado menor do que a LTE nas regiões com aço comum. / The first studies on continuously reinforced concrete pavements (CRCP) were developed in areas in which the typical weather is temperate (United States, Netherlands and Belgium), with no technical studies carried out in tropical weather. CRCP structural premise is based on a slab without construction joints which are required in jointed plain concrete pavements (JPCP); i.e., CRCP cracks due to concrete shrinkage occur randomly being controlled by the high longitudinal reinforcement percentage, positioned longitudinally along the pavement length. As the longitudinal reinforcement has no structural role, because it is placed above the slab neutral axis, in the compression zone, its main function is to keep cracks strongly tight, ensuring a smooth ride and high load efficiency transfer (LTE) at cracks, which occurs through aggregates interlocking, thereby providing a highly durable pavement with low maintenance costs. The first experience with CRCP in Brazil started in 2010, when four experimental sections were constructed. Each section is 50 meters long, short when compared to the traditional CRCP that can extend for over 400 meters providing that concrete pouring does not stop. Continuous monitoring of these sections has shown that the short CRCP behaves differently from traditional CRCP, regarding the time taken for the cracking pattern full development (the first crack was visible on the surface one year after the construction), as well as average cracking space due to the slab\'s short extension and lack of anchorage. Therefore, in order to fully analyze the behavior of a traditional CRCP under tropical weather, in January 2016, the first long extension CRCP in Brazil was built, at the University of São Paulo campus, with 200 meters length. Four types of concrete were applied in the construction, varying cement and aggregate type. Galvanized and ordinary steel were used as well. To analyze the pavement behavior under Brazilian climatic conditions, three studies were carried out: cracks surveys (spacing and width), analytical modeling crack spacing through shrinkage prediction models and Falling Weight Deflectometer testing to evaluate the crack\'s load transfer efficiency (LTE). Cracking pattern analysis has shown cracks development consistent with technical literature. The first cracks appeared during the first week after concrete placement and, before the first month, about 60% of the total cracks number had developed. Central sections presented greatest number of cracks as they are anchored by the outer sections, where cracking occurs slower due to the lack of anchorage. Cracks width was higher in areas with galvanized steel due to the weaker steel-concrete bond, when compared to areas with common steel. The shrinkage prediction model for concrete that better approached the average field crack spacing was the Eurocode 2, with mean difference of 30%. LTE analysis has shown a quite satisfactory performance, even though LTE in areas with galvanized steel is lower than LTE in areas with common steel.

Electric and hybrid vehicles are particularly suited for use in urban areas since city transportation is mainly characterized by relatively short driving distances, low continuous power requirements, long idling times and high availability of regenerative braking energy. These characteristics, when carefully incorporated into the design process, create valuable opportunities for developing clean, efficient and cost effective urban vehicle propulsion systems. In the first part of the thesis, we present data collected in the city of Bangalore, India from a very commonly seen mode of transportation for hire in India and other emerging economies, namely a three-wheeled vehicle known as the “auto-rickshaw”. From a statistical analysis, it is shown that the typical range is 72.5 km with a mean speed of 12.5 km/h. More than 60% of the time the auto-rickshaw is stationary or has a speed of less than 5 km/h. From a model of the auto-rickshaw, it is shown from simulations that 4 kW DC motor and about 10 kWh of electrical energy is enough to meet 80% of typical requirement. Based on this finding, in this thesis, a novel parallel hybrid architecture is proposed where two 2 kW DC hub motors are directly mounted on the wheels and an internal combustion (IC) engine output is connected to the stator of the DC hub motors to provide additional power when required. To match load and speed, a continuously variable transmission (CVT) is placed in-between the IC engine and the DC hub motor. The proposed hybrid configuration adds speed to the wheel output unlike the normal power split configuration which adds torque. One of the main objective of this work is to study and compare the performance of the above novel speed-addition and compare with the typical torque-addition configuration. A MATLAB/Simulink model for both the configurations, with DC hub motor and a small IC engine, has been created and the fuel consumption has been calculated. It is shown that the proposed speed-addition concept gives better fuel efficiency for the standard modified Indian Driving Cycle. The models have also been compared for actual driving data and an optimal control strategy has been developed using dynamic programming. It is again shown that the proposed speed-addition concept results in better fuel economy. In the last part of the thesis, a low cost experimental test-bed consisting of an auto-rickshaw IC engine, a CVT and a 2 kW DC hub motor has been developed to validate the speed-addition concept and compare with the torque-addition configuration. The torque-speed curves of the IC engine, the DC motor and both of them together, in the speed and torque-addition configuration, have been obtained. It is shown that the speed-addition concept does indeed work and the obtained results are significantly different from the torque-addition configuration.

In this study, an innovative solution is examined for transmission problems and frequency control for wind Turbines. Power electronics and the gear boxes are the parts which are responsible of a significant amount of failures and they are increasing the operation and maintenance cost of wind turbines. Continuously transmission (CVT) systems are investigated as an alternative for conventional gear box technologies for wind turbines in terms of frequency control and power production efficiency. Even though, it has being used in the car industry and is proven to be efficient, there are very limited amount of studies on the CVT implementation on wind turbines. Therefore, this study has also an assertion on being a useful mechanical analyse on that topic. After observing several different types of possibly suitable CVT systems for wind turbines; a blade element momentum code is written in order to calculate the torque, rotational speed and power production values of a wind turbine by using aerodynamic blade properties. Following to this, a dynamic model is created by using the values founded by the help of the blade element momentum theory code, for the wind turbine drive train both including and excluding the CVT system. Comparison of these two dynamic models is done, and possible advantages and disadvantages of using CVT systems for wind turbines are highlighted. The wind speed values, which are simulated according to measured wind speed data, are used in order to create the dynamic models, and Matlab is chosen as the software environment for modelling and calculation processes. Promising results are taken out of the simulations for both in terms of energy efficiency and frequency control. The wind turbine model, which is using the CVT system, is observed to have slightly higher energy production and more importantly, no need for power electronics for frequency control. As an outcome of this study, it is possible to say that the CVT system is a candidate of being a research topic for future developments of the wind turbine technology.

No description available.

No description available.

No description available.