Small combined heat and power generators have the potential to reduce energy consumption and greenhouse gas emissions of residential buildings. Recently, much attention has been given to these units. To date, the majority of studies in this field have concentrated on the steady operational performance of a specific generator type, and the available computer models have largely been theoretical in nature. <br /><br /> The main goal of this study was to evaluate the performance of the latest combined heat and power generators, when integrated into Canadian residential homes. A fair comparison of four 1 kW (electrical) units was made. The combined heat and power units studied were based on PEM fuel cell, solid oxide fuel cell, Stirling Engine, and internal combustion engine energy converters. <br /><br /> This study utilized recent test data in an attempt to evaluate the most efficient method of integrating the combined heat and power units into residential houses. Start-up, shut down, and load change transients were incorporated into the simulations. The impact of load variations due to building thermal envelope differences and varying building heating system equipment was evaluated. The simulations were evaluated using TRNSYS software. The building heat demands were determined with eQuest hourly building simulation software. <br /><br /> All of the combined heat and power units under study were capable of providing a net annual benefit with respect to global energy and greenhouse gas emissions. The fuel cells offer the highest integrated performance, followed closely by the internal combustion engine and lastly the Stirling engine. Annual global energy savings up to 20%, and greenhouse gas savings up to 5. 5 tonnes per year can be achieved compared to the best conventional high efficiency appliances. <br /><br /> Heat demand influences performance greatly. As the thermal output of the generator unit approaches half of the average building thermal demand, the system design becomes critical. The system design is also critical when integrating with a forced air furnace. Only the PEM fuel cell unit produces clear global energy and emissions benefits when operating in the summertime.

The mobile preschools of Uppsala are buses that are provided as a complement for stationary preschools. The buses are connected to one stationary preschool that provides the necessities such as food and a place for the children to be before and after the daily trips. In Uppsala, there are five mobile preschool buses and they have been operated since 2009. For the bus to provide heat, warm food and energy for activities on the bus, there is a generator installed that runs on biodiesel. The emissions from the generator, in combination with the loud noises that it emits, are of concern for both the children and educators on the bus as well as the people around it. This has caused for alternative ways to deliver electricity to the bus. This study examines three scenarios for delivering electricity and tries to evaluate what the best option could be from different Points of view. The three scenarios are replacing the generator with either a battery, replacing the generator with electricity poles and to replace the generator with a more efficient and quieter one. When evaluating the different scenarios from an economical point of view, the study found that the electricity poles would be the best option. When evaluating the best option with respect to the children and educators, the study found that the battery would be the best option. The negative consequences for continuing to use a generator to supply electricity would be a health hazard for the children and a limitation for the educators in the freedom of choosing location for the bus to visit.

For those who have suffered a stroke, damage to the brain can result in a decreased ability to walk. The traditional therapy used for the recovery of walking, body weight supported treadmill training, has significant labour requirements that limit the availability of training to the larger stroke population. Thus, the conception and application of new, effective, and efficient rehabilitation therapies is required. To approach this, an understating of the intricate neural control behind walking is needed to form the principled foundation upon which locomotor therapies are based. Due to observations that the arms and legs are connected in the nervous system during walking, and that nervous system control is the same across rhythmic tasks, arm and leg (A&L) cycling training could provide an effective means of locomotor rehabilitation. Thus, the goal of this dissertation is focused upon exploring central nervous system control and interlimb coordination during rhythmic arm and leg movement and testing the extent to which A&L cycling training improves walking after stroke. The first objective of this dissertation was to provide further evidence of central nervous system control of walking. Through a literature review in Chapter 1 and experimental evidence in Chapter 2 of common subcortical control across rhythmic locomotor tasks, evidence for the existence of central pattern generating networks in humans is given. The second objective was to explore interlimb coordination during rhythmic movement. Results presented in Chapters 3 and 4 further our understanding of specific interlimb interactions during rhythmic arm and leg tasks. The third objective was to evaluate the effects of an A&L cycling training intervention in a post-stroke population. To support this objective, it was shown in Chapter 5 that a multiple baseline design is appropriate for use in intervention studies. In Chapter 6, it was determined that A&L cycling training can be used to improve walking ability. And in Chapter 7, it was shown that training induced plasticity in interlimb reflex pathways. Overall, results in this dissertation provide further knowledge on nervous system control and arm and leg interlimb interactions during rhythmic movements and their effect on locomotor recovery following a stroke. / Graduate / 2017-10-31

The aim of this thesis is to research the current possibilities and limitations of automatic generation of synthetic XML documents. The first part of the work discusses the properties of the most used XML data generators and compares them to each other. The next part of the thesis proposes an algorithm for XML data generation which focuses on subset of the main XML data characteristics (number of elements, number of attributes, fan-out, mixed contents etc.). The main target of the algorithm is to generate XML documents using a set of settings which are easy to understand. The last part of the work compares the proposed solution with the existing ones. The comparison focuses on how easy it is to generate XML documents, what structures can be created and finally it compares properties of the similar XML data created using different XML data generators. Powered by TCPDF (www.tcpdf.org)

The aim of this thesis is to research the current possibilities and limitations of automatic generation of synthetic XML documents. The first part of the work discusses the properties of the most used XML data generators and compares them to each other. The next part of the thesis proposes an algorithm for XML data generation which focuses on subset of the main XML data characteristics (number of elements, number of attributes, fan-out, mixed contents etc.). The main target of the algorithm is to generate XML documents using a set of settings which are easy to understand. The last part of the work compares the proposed solution with the existing ones. The comparison focuses on how easy it is to generate XML documents, what structures can be created and finally it compares properties of the similar XML data created using different XML data generators. Powered by TCPDF (www.tcpdf.org)

Oceans cover two thirds of the Earth’s surface and the energy potential of ocean waves as a renewable energy source is huge. It would therefore be a tremendous achievement if the vast mechanical energy in waves was converted into a form of energy that could be used successfully by society. For years, scientists and engineers have endeavored to exploit this renewable energy by inventing various generators designed to transform wave energy into electrical energy. Generally, this sort of generator is called a Wave Energy Converter (WEC). In this thesis, the research is based on the WEC developed in the Lysekil Project. The Lysekil Project is led by a research group at Uppsala University and has a test site located on the west coast of Sweden. The project started in 2002. So far, more than ten prototypes of the WEC have been deployed and relevant experiments have been carried out at the test site. The WEC developed at Uppsala University can be categorized as a point absorber. It consists of a direct-drive linear generator connected to a floating buoy. The linear generator is deployed on the seabed and driven by a floating buoy to extract wave energy. The absorbed energy is converted to electricity and transmitted to a measuring station on land. The work presented in this thesis focuses on building a linear generator model which is able to predict the performance of the Lysekil WEC. Studies are also carried out on the damping behavior of the WEC under the impact of different sea climates. The purpose is to optimize the energy absorption with a specific optimal damping coefficient. The obtained results indicate an optimal damping for the Lysekil WEC which can be used for optimizing the damping control. Additionally, the impact two central engineering design features (the translator weight and the stroke length) are investigated. The aim is to find a reasonable structural design for the generator which balances the cost and the energy production.

Student Number : 9608998A - MSc dissertation - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / The history of flux compression is relatively short. One of the founders, a Russian physicist, Sakharov developed the idea of compressing a magnetic field to generate high magnetic fields and from this he also developed a generator to produce current impulses. Most of this initial work was performed in military research laboratories. The first open source literature became available in the 1960s and from there it has become an international research arena. There are two types of flux compression generators, field generators and current generators. These are discussed along with the basic theory of flux compression generators and related physics. The efficiency of generators is often quite low. However in many generators high explosives are used and because of their high energy density, the current or field strength produced is substantially greater then the initial source. This of course limits the locations possible for experimental work and subsequently limits the industrial applications of flux compression generators . This research presents a theoretical design for a non-explosive flux compression generator. The generator is designed to produce a current impulse for tests in laboratory and remote locations. The generator has the advantage of being non-destructive, therefore reducing costs, and allowing for repeatable experiments. The design also reduces the possibilities or many of the loss mechanisms.

Student Number :0008015M - MSc Dissertation - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / Shaft voltages and currents are an unavoidable characteristic of rotating machines, though they are typically a nuisance this work shows that shaft signals can be used for fault diagnosis. This work focussed on shaft voltages present on synchronous generators. Measurements on a 4-pole generator found that the angular position of the shaft could be determined from the shaft voltage. An experimental 20 kVA 2-pole synchronous generator was designed and built which resembled a full-size 600 MVA turbo-generator. The effects of a static eccentricity on the shaft voltage were successfully determined firstly through FEM simulation and then verified with physical measurements. Shaft voltages can be used to diagnose static eccentricity, future work should investigate other faults. In addition, computer simulation was found to be effective and simulation and measurements of operating machines (such as turbo-generators) should be considered.

Este trabalho consiste na implementação de um gerador gráfico que propiciará a discretização de estruturas lineares formadas pela união de subestruturas. Estruturas com muitos graus de liberdade serão calculadas através da sua divisão em subestruturas, permitindo uma significativa diminuição nas dimensões das matrizes envolvidas. A aplicação da técnica das subestruturas irá permitir, também, a análise de diferentes tipos estruturais interligados, como pórticos e treliças, compatibilizando os deslocamentos comuns nos nós de união. O gerador gráfico irá tratar as subestruturas como sendo entidades próprias, isoladas, conferindo a elas características que possibilitarão transformações gráficas durante a sua edição. Pretende-se que o gerador gráfico condicione a uma melhor organização na discretização estrutural, como também venha a facilitar todo o processo de lançamento da estrutura. Do mesmo modo, cria condições para submeter adequadamente os resultados de cálculo a outros programas, como os de dimensionamento e detalhamento. / This work consists of the implementation of a graphic generator that will propitiate the discretization of lineal structures formed by the substructures union. Structures with many degrees of freedom will be calculated through its division in substructures, allowing a significant decrease in the dimensions of the involved matrix. The application of the technique of the substructures will allow, also, the analysis of different interlinked structural types, as frames and trusses, based on the compatibility of the common displacements in the union knots. The graphic generator will treat the substructures as being own, isolated entities, checking them characteristics that will facilitate graphic transformations during its edition. It is intended that the graphic generator conditions to a better organization in the structural discretization, as well as come to facilitate the whole process of release of the structure. In the same way, it creates conditions to submit the calculation results appropriately the other programs, as the one of design and details.

O objetivo deste trabalho é a investigação de um algoritmo adaptativo para compensação dos erros no cálculo dos fasores do sistema de potência quando há variações significativas na freqüência dos sinais de tensão e corrente. O principal benefício desta técnica é permitir a compensação dos erros utilizando freqüência de amostragem e janela de dados constantes, possibilitando a construção de relés microprocessados para proteção de geradores com hardware mais simples. O algoritmo adaptativo denominado AIVF (Algoritmo Inume a Variações de Freqüência) foi testado a partir de uma série de sinais com características como variação da freqüência da fundamental, componente exponencial amortecida e harmônicos, sendo os resultados apresentados no capítulo 4.4. Além do AIVF, nos capítulos iniciais são apresentados aspectos inerentes à proteção de geradores como aterramento e uma descrição das principais proteções aplicáveis a geradores de até 50MVA. / The main pourpose of that work is inquire an adaptive algorithm to compensate the errors in the power system phasors calculation when occur significant changes in the frequency of the current and voltage signals. The main benefit of that technique is to permit errors compensation with constant sampling frequency and constant data window, making possible construction of microcomputer relays for generator protection with simple hardware. The adaptive algorithm named ANAFC (Algorithm Not Affected by Frequency Changes) was tested by some signals with characteristics like changes in the fundamental frequency, dc decaying and harmonics. The results are presented in the section 4.4. Beyond ANAFC, in the initial sections are presented aspects regarding generator protection like earthing and a description of the main protection functions applied in generators till 50MVA.