Este trabalho apresenta um modelo híbrido, que após calcular as cargas e as vazões para o regime permanente e para o regime extensivo, utiliza um algoritmo genético para otimizar o controle operacional de redes hidráulicas. Para se calcular os regimes permanente e extensivo utilizou-se o Método Matricial. O Algoritmo Genético utilizou números binários. A função objetivo minimiza a soma das potências hidráulicas dissipadas na rede como um todo de todos os períodos de cálculo do regime extensivo. A parte do modelo híbrido que se refere ao cálculo hidráulico está funcionando a contento, pois os valores obtidos pelo modelo para as duas redes utilizadas como exemplo neste projeto estão próximos dos valores originais obtidos da literatura pesquisada. A parte do modelo híbrido que se refere ao algoritmo genético está funcionando a contento, pois os valores da função objetivo obtidos pelo modelo convergiram em todos os cálculos nos quais o elitismo foi utilizado. A otimização proposta neste trabalho serve para ser utilizada em redes de abastecimento que apresentem problemas operacionais e que precisem ser resolvidos com a instalação de válvulas ou que tenham válvulas instaladas. / This report presents a hybrid model that calculates the heads and flows of a hydraulic network system and then uses a genetic algorithm to optimize the operational control of the hydraulic network. To calculate the steady flow and the extensive period it was used the Matrix Method. The GA used binary numbers. The objective function minimizes the sum of the dissipated hydraulic power in the whole network of all calculated periods during the day. The hybrid model part that refers to the hydraulic calculation is working well, because the values calculated by the model applied to the networks used as examples are similar to the ones obtained from the technical literature. The hybrid model part that refers to the GA is working well, because the objective function values calculated by the model converged whenever the elitism was used. The proposed optimization of this work is to be used in hydraulic networks that present operational problems that need to be solved either installing valves or having installed valves.

This work considers the value of flexible power provision from natural gas-fired combined cycle (NGCC) power plants operating post-combustion carbon dioxide (CO2) capture in low carbon electricity markets. Specifically, the work assesses the value of the flexibility gained by varying CO2 capture levels, thus the specific energy penalty of capture and the resultant power plant net electricity export. The potential value of this flexible operation is quantified under different electricity market scenarios, given the corresponding variations in electricity export and CO2 emissions. A quantified assessment of natural gas-fired power plant integrated with amine-based post-combustion capture and compression is attempted through the development of an Aspen Plus simulation. To enable evaluation of flexible operation, the simulation was developed with the facility to model off-design behaviour in the steam cycle, amine capture unit and CO2 compression train. The simulation is ultimately used to determine relationships between CO2 capture level and the total specific electricity output penalty (EOP) of capture for different plant configurations. Based on this relationship, a novel methodology for maximising net plant income by optimising the operating capture level is proposed and evaluated. This methodology provides an optimisation approach for power plant operators given electricity market stimuli, namely electricity prices, fuel prices, and carbon reduction incentives. The techno-economic implications of capture level optimisation are considered in three different low carbon electricity market case studies; 1) a CO2 price operating in parallel to wholesale electricity selling prices, 2) a proportional subsidy for low carbon electricity considered to be the fraction of plant electrical output equal to the capture level, and 3) a subsidy for low carbon electricity based upon a counterfactual for net plant CO2 emissions (similar to typical approaches for implementing an Emissions Performance Standard). The incentives for variable capture levels are assessed in each market study, with the value of optimum capture level operation quantified for both plant operators and to the wider electricity market. All market case studies indicate that variable capture is likely to increase plant revenue throughout the range of market prices considered. Different market approaches, however, lead to different valuation of flexible power provision and therefore different operating outcomes.

With wind energy becoming a major source of energy, there is a pressing need to reduce all associated costs to be competitive in a market that might be fully subsidy-free in the near future. Before thousands of wind turbines were installed all over the world, research in e.g. understanding aerodynamics, developing new materials, designing better gearboxes, improving power electronics etc., helped to cut down wind turbine manufacturing costs. It might be assumed, that this would be sufficient to reduce the costs of wind energy as the resource, the wind itself, is free of costs. However, it has become clear that the operation and maintenance of wind turbines contributes significantly to the overall cost of energy. Harsh environmental conditions and the frequently remote locations of the turbines makes maintenance of wind turbines challenging. Just recently, the industry realised that a move from reactive and scheduled maintenance towards preventative or condition-based maintenance will be crucial to further reduce costs. Knowing the condition of the wind turbine is key for any optimisation of operation and maintenance. There are various possibilities to install advanced sensors and monitoring systems developed in recent years. However, these will inevitably incur new costs that need to be worthwhile and retro-fits to existing turbines might not always be feasible. In contrast, this work focuses on ways to use operational data as recorded by the turbine's Supervisory Control And Data Acquisition (SCADA) system, which is installed in all modern wind turbines for operating purposes -- without additional costs. SCADA data usually contain information about the environmental conditions (e.g. wind speed, ambient temperature), the operation of the turbine (power production, rotational speed, pitch angle) and potentially the system's health status (temperatures, vibration). These measurements are commonly recorded in ten-minutely averages and might be seen as indirect and top-level information about the turbine's condition. Firstly, this thesis discusses the use of operational data to monitor the power performance to assess the overall efficiency of wind turbines and to analyse and optimise maintenance. In a sensitivity study, the financial consequences of imperfect maintenance are evaluated based on case study data and compared with environmental effects such as blade icing. It is shown how decision-making of wind farm operators could be supported with detailed `what-if' scenario analyses. Secondly, model-based monitoring of SCADA temperatures is investigated. This approach tries to identify hidden changes in the load-dependent fluctuations of drivetrain temperatures that can potentially reveal increased degradation and possible imminent failure. A detailed comparison of machine learning regression techniques and model configurations is conducted based on data from four wind farms with varying properties. The results indicate that the detailed setup of the model is very important while the selection of the modelling technique might be less relevant than expected. Ways to establish reliable failure detection are discussed and a condition index is developed based on an ensemble of different models and anomaly measures. However, the findings also highlight that better documentation of maintenance is required to further improve data-driven condition monitoring approaches. In the next part, the capabilities of operational data are explored in a study with data from both the SCADA system and a Condition Monitoring System (CMS) based on drivetrain vibrations. Analyses of signal similarity and data clusters reveal signal relationships and potential for synergistic effects of the different data sources. An application of machine learning techniques demonstrates that the alarms of the commercial CMS can be predicted in certain cases with SCADA data alone. Finally, the benefits of having wind turbines in farms are investigated in the context of condition monitoring. Several approaches are developed to improve failure detection based on operational statistics, CMS vibrations or SCADA temperatures. It is demonstrated that utilising comparisons with neighbouring turbines might be beneficial to get earlier and more reliable warnings of imminent failures. This work has been part of the Advanced Wind Energy Systems Operation and Maintenance Expertise (AWESOME) project, a European consortium with companies, universities and research centres in the wind energy sector from Spain, Italy, Germany, Denmark, Norway and UK. Parts of this work were developed in collaboration with other fellows in the project (as marked and explained in footnotes).

Energy consumption in electric locomotives is principally the power consumed in traction motors. In order to reduce this energy consumption, the motion resistances of the train need to be reduced. These resistances include aerodynamics; inertial and grade forces; curving resistance; and bearing and wheel/rail friction. Though many factors such as gradient resistance cannot be modified, if a control system is included, curving resistance can be minimised by reducing the energy losses in the contact patches between wheel and rail. Therefore, operational practices could be modified in order to obtain the most appropriate wheelset attack angle between wheel and rail, and appropriate train speed. One solution is to implement a steering control system. The function of this control system is to monitor and control the wheelset lateral displacement or the attack angle of the wheelset. This could reduce the energy dissipated at the contact points between wheel and rail, consequently reducing the energy consumed by traction motors in railway vehicles. Therefore, the work presented in this thesis aims to design and develop a control method for combined vehicle traction and wheelset active steering control systems and to assess the energy efficiency of a rail vehicle under typical operational conditions. In order to achieve these aims, two dynamic models of a typical railway vehicle have been developed in MATLAB and Simulink. The first model comprises the electrical traction and mechanical system passive system). The second model includes the passive and the wheelset active steering control system (active system). These models are used to determine the relationship between traction energy consumption and the energy dissipated in the contact points between wheel and rail, and to compare the passive steering system to the wheelset active steering control system, determining the possibilities for energy saving. In order to assess the influence of the wheelset active steering control on the relationship between wheel and rail contact forces and traction power a series of deterministic track features are set comprising curve radii with different cant deficiencies and wheel conicities. Also a typical track profile from Leeds to Hull is used. From these simulations, the traction energy consumption, energy dissipated at the contact patches, and energy consumed by the steering actuators are calculated. Statistical analyses are used to understand the relationship between the traction power and wheelset motion dynamics (lateral displacement and attack angle). The active vehicle model scheme is used to investigate the improvement of the energy efficiency of a railway vehicle using active steering. The wheelset active steering control system analysis shows whether different combinations of vehicle speed, wheelset conicity and track curve radius lead to a reduction, no reduction, or an increase intraction power consumption. The probability of high power consumption under different conditions is assessed to ensure that it is reduced wherever possible. The ability of a forecasting model to predict the traction power consumption behaviour of railway vehicles from the wheelset motion dynamic is assessed. Findings show that the overall prediction accuracy is fairly similar to the power measured from the passive vehicle running on a track from Leeds to Hull. However, the algorithm does not perform effectively for the deterministic track features. Finally, the benefits of implementing wheelset active steering control systems in terms of the mitigation of contact forces between wheels and rails and how this mitigation influences traction energy consumption are evaluated to determine under what conditions energy can be saved.

The argument for this thesis is that patterns of past engineering and operational development can be used to support the creation of a strategy for future development and that, in order to achieve this, a corporate understanding of the history of the engineering, operational and organisational changes in the business is essential for any railway undertaking. The research shows that a railway is a complex system, where the operational life of much of the hardware is greater than the time employees spend in service, so it is common for the origins and reasons for systems on the railway to be forgotten. This knowledge can be lost when staff retire or leave. For new staff, little attention is paid to history and development during induction; indeed, such knowledge may not even be considered necessary or relevant. London Underground is used as a case study to show how the history of the system has impacted on the design of rolling stock. The work concludes that it is essential for railway employees to understand the way in which systems and operations have evolved on a railway during its history. The author proposes new processes that include historical corporate knowledge in future business development.

Quandles are distributive algebraic structures originally introduced independently by David Joyce and Sergei Matveev in 1979, motivated by the study of knots. In this dissertation, we discuss a number of generalizations of the notion of quandles. In the first part of this dissertation we discuss biquandles, in the context of augmented biquandles, a representation of biquandles in terms of actions of a set by an augmentation group. Using this representation we are able to develop a homology and cohomology theory for these structures. We then introduce an n-ary generalization of the notion of quandles. We discuss a number of properties of these structures and provide a number of examples. Also discussed are methods of obtaining n-ary quandles through iteration of binary quandles, and obtaining binary quandles from n-ary quandles, along with a classification of low order ternary quandles. We build upon this generalization, introducing n-ary f-quandles, and similarly discuss examples, properties, and relations between the n-ary structures and their binary counter parts, as well as low order classification of ternary f-quandles. Finally we present cohomology theory for general n-ary f-quandles.

No description available.

After a long period of isolation, China embarked on an open door policy in 1978. Keen to modernize her economy and improve her living standards, China sought to intensify her economic relations with Japan, one of her closest neighbours and one of the most advanced and dynamic economies in the world. An air of optimism marked the signing of the Japan-China Long Term Trade Protocol in 1978. China was confident that this agreement would launch her into the path of modernization in a relatively short period of time. This process of intensification of economic links with Japan, however, was not without difficulties. Over the years between 1979 and 1985, the Chinese failed to fulfil key obligations of the agreement including the non-payment for service received and the permiting of, severe shortfalls in the supply of agreed goods. The execution of the agreement was beset with problems. The agreement from which both sides had hoped to reap substantial economic benefits did not bear fruit; instead friction developed, which had ensued with disastrous consequences for both sides. What was the root cause of this friction? Was it the consequence of the incompatibility of the economic systems, one communist and the other capitalist? Or was the failure the result of political factors? Or could it be a much deeper reason relating to inherent socio-cultural factors which affected the decision-making processes in each of the countries? This thesis seeks to examine closely the root cause of the Chinese-Japanese trade friction. The writer argues that while different ideologies and political systems contributed to the problem, the dominant reason has socio-cultural origins, which have to do with the way the Chinese and Japanese societies evolved historically. Although both societies had Confucian ethical underpinnings of their social systems, they began to develop their own distinct characteristics. This coloured their world views and had a major impact in the way each society evolved its management practices. The Chinese rejection of some key aspects of Confucianism and its acceptance of Qinstyle authoritarianism, as subsequently modified by Sino- Marxist principles, produced an organisational framework and set of practices that did not prepare China to meet the demands of economic modernisation. This had adversely effected China's abilities to manage its trade relations with the economically advanced Japan. Section One of this thesis, which includes Chapters 1 and 2, outlines the framework of Chinese-Japanese trade cooperation beginning in the late 1970's. Chapter 1. seeks to give an overview of the rationale behind China's new open-door policy and its expectations of trade co-operation with Japan. It outlines the nature of trade co-operation including the structure of China-Japan trade. Chapter 2. proceeds to discuss the ensuing difficulties and the responses of the Chinese and Japanese governments. The writer then discusses the subsequent actions taken by the two governments to revive the co-operation that had gone wrong. An analysis of the faults of both governments that led to the disastrous consequences is then made. Section Two, which includes Chapters 3 and 4, seeks to examine the fundamental causes of the friction in the trade relations between the two countries. The writer examines the role played by socio-cultural factors and how they affected the decision-making processes in both countries. In particular, Chapter 3. analyses the role of feudalism in China as modified by the emergence of the centralized bureaucracy which characterize the Qin dynasty (221 to 207 BC). The impact of the anti-merchantilism, which was the direct consequence of Qin-style bureaucracy, and the question of the destruction of the urban middle class by the bureaucracy are highlighted. The writer argues that the absence of the urban middle class is one of the fundamental reasons why China is unable to produce an economically-progressive, capitalist-oriented society. This led to a state of economic backwardness. Chapter 4. contrasts the Chinese situation with Japan, by analysing the ideological underpinning of Japanese society. It outlines the various reform movements in Japan that led to the development of a society that is economically dynamic . A modern state has emerged in Japan in contrast to the emergence of a backward society in China. The writer also discusses the influence of Japanese Confucian values in the development of this modern state. This was to have a significant impact on Japanese management philosophy and practices. The last Section, which includes Chapter 5, 6, and 7, discusses the lessons to be learnt from the trade friction betwen the two countries. In particular, Chapter 5. analyses the vastly different approaches taken by the Chinese in contrast to the Japanese. The Chinese decision-making process which is characterized by chaos, inefficiency and bureaucratic bungling is contrasted with the Japanese style. The latter's approach is systematic, well thought out and meticulously planned. The Japanese, however, failed to take into account the vastly different operating environment in their dealings with China. Chinese behavioural responses were a variable that the Japanese were unprepared to deal with. This resulted in chaos in the strategic management of the trade relations between the two countries. Notwithstanding this friction, however, both China and Japan realize that they must proceed with their trade relations and minimize whatever frictions emerged over time. The last part of the thesis, Chapter 6. outlines the possible approaches that both sides can adopt in their dealings with each other. An approach with Lindblom's "muddling through" perspective is recommended by the writer. Chapter 7 contains the conclusion drawn from this study.

<p>Bakgrund: Redan år 1936 gjordes undersökningar i USA som visade på att oro kunde minskas genom god information inför medicinsk behandling. Syfte: Beskriva barnets behov av förberedelse inför operation. Metod: Detta är en systematisk litteraturstudie där artiklarna söktes i databaserna PubMed, Cinahl och PsycInfo. Fjorton artiklar inkluderades och som har analyserats. Tre kategorier bildades; Ångest, förberedelse och delaktighet. Resultat: Barn upplever ångest inför främmande situationer. Det finns sätt att lindra denna ångest både pre- och postoperativt, exempelvis lekterapi. Föräldrars och barns ångest står i direkt relation till varandra. Diskussion: Förberedelse inför operation är viktigt för att barnet ska kunna behålla sin integritet i en miljö som kontrolleras av vuxna. Barnen måste kunna känna trygghet och tillit för att kunna hantera den stress som uppkommer i obehagliga situationer. Mer forskning inom området behövs eftersom vården och samhället hela tiden utvecklas.</p>

<p>Det största folkhälsoproblemet bland kvinnor är hjärt-kärlsjukdom. Kvinnor är underrepresenterade bland patienter som får behandling i form av CABG-operation . CABG-operation är ett stort kirurgiskt ingrepp som innebär påfrestningar och en stor förändring i livet. Syftet med litteraturstudien var att belysa kvinnors upplevelse av livskvalitet efter CABG-operation. Studien genomfördes som en systematisk litteraturstudie, en metod för att sammanställa alla vetenskapliga arbeten inom ett specifikt område. Sju artiklar som var relevanta till syftet och hade hög vetenskaplig kvalitet analyserades och sammanställdes till resultatet. Resultatet visade att de flesta kvinnor upplevde någon form av problem postoperativt. Kvinnorna upplevde sin fysiska funktion nedsatt efter operation för att under första året återgå till jämförbar nivå med friska kvinnor. Ensamhet påverkar den sociala rehabiliteringen negativt. Familj och vänner var en bidragande faktor till att den sociala rehabiliteringen förbättrades. Postoperativt var kvinnornas totala upplevelse av livskvalitet signifikant förbättrad. Fortsatt forskning bör inriktas på enbart kvinnors upplevelse av livskvalitet efter CABG-operation, för att enklare kunna applicera kunskapen i praktiken.</p>