Independentemente do nível de verticalização ou da sua escala de produção, a redução de custos e o aumento de produtividade têm sido os principais focos internos das empresas da indústria do aço. Dois fatores controlam fundamentalmente o custo de produção do aço: o preço e o consumo dos insumos e matérias-primas. O primeiro depende fortemente do poder de barganha da empresa e das condições de mercado e, muitas vezes, não é possível exercer grande controle sobre ele. Sendo assim, é através da diminuição do consumo específico dos insumos e matérias-primas que a empresa pode obter sucesso na sua missão, internamente, de maximizar seu lucro. Em aciarias elétricas, o consumo dos insumos tem impacto importante na composição do custo final do aço, dos quais se destaca o consumo de energéticos utilizados no forno elétrico a arco, que pode representar até 30% do custo operacional desse tipo de aciaria. Para quantificar o aporte desses diferentes tipos de energia no forno, normalmente é utilizado o indicador de consumo de energia total, que utiliza o poder calorífico de cada tipo de energético na transformação para a unidade de kWh/t. O objetivo desse trabalho foi avaliar o impacto na eficiência energética do forno, medida através do consumo de energia total, da redução da vazão de gás natural nos modos lança e da modificação da proporção entre oxigênio e gás natural (O2/GN) em um dos modos queimador do sistema de injeção de um forno elétrico a arco. Para tanto, foi realizado um teste estatístico dividido em quatro cenários no formato de projeto de experimentos (DOE). O cenário em que as modificações no modo queimador e nos modos lança foram aplicadas conjuntamente apresentou a maior redução no consumo de energia total (2,50%), impulsionada principalmente pelas reduções no consumo de gás natural (16,94%) e no consumo de energia elétrica de forno e forno-panela (-1,90%). Através da análise do carbono de vazamento de todas as corridas não foi possível afirmar que os ganhos em consumo de energia elétrica foram provenientes de uma maior oxidação de ferro da carga nas corridas. / Companies have been extensively focusing on cost reduction and productivity optimization in the last few years, independently of their levels of production or verticalization. The cost of production is basically controlled by two factors: the price and the consumption of raw and input materials. The price depends on the current conditions of the market and the capacity of the company to deal with its suppliers about the price to be paid. Due to that, it is very difficult to control this factor and for this reason, through the reduction in raw material and inputs consumption that companies can achieve their mission of becoming more profitable. In electric steelmaking, consumption of inputs plays an important role on the final billet cost, with particular emphasis to the energy consumption in the electric arc furnace, which can represent up to 30% of the operational cost in a melt shop. To quantify the contribution of different types of energy in the furnace, it is used the performance indicator of total energy consumption, which associates the heat of combustion of each type of energetic in order to use the unit kWh/t. The aim of this study was to evaluate the impact on the energy efficiency of the furnace, measured by the total energy consumption, reducing the flow of natural gas in lance modes and modifying the ratio between oxygen and natural gas (O2/NG) in one of the burner modes of the injection system in an electric arc furnace. Thus, a statistical test divided into four scenarios in the format of design of experiments (DOE) was conducted. The scenario in which the burner mode and lance mode modifications were applied together resulted in the greatest reduction in total energy (2,50%), driven especially by reductions in natural gas consumption (16,94%) and electrical energy consumption of furnace and ladle furnace (1,90%). Through the analysis of tapping carbon of all heats it was not possible to assert that gains in electrical energy were due to a higher oxidation of iron contained in the blend charged.

Independentemente do nível de verticalização ou da sua escala de produção, a redução de custos e o aumento de produtividade têm sido os principais focos internos das empresas da indústria do aço. Dois fatores controlam fundamentalmente o custo de produção do aço: o preço e o consumo dos insumos e matérias-primas. O primeiro depende fortemente do poder de barganha da empresa e das condições de mercado e, muitas vezes, não é possível exercer grande controle sobre ele. Sendo assim, é através da diminuição do consumo específico dos insumos e matérias-primas que a empresa pode obter sucesso na sua missão, internamente, de maximizar seu lucro. Em aciarias elétricas, o consumo dos insumos tem impacto importante na composição do custo final do aço, dos quais se destaca o consumo de energéticos utilizados no forno elétrico a arco, que pode representar até 30% do custo operacional desse tipo de aciaria. Para quantificar o aporte desses diferentes tipos de energia no forno, normalmente é utilizado o indicador de consumo de energia total, que utiliza o poder calorífico de cada tipo de energético na transformação para a unidade de kWh/t. O objetivo desse trabalho foi avaliar o impacto na eficiência energética do forno, medida através do consumo de energia total, da redução da vazão de gás natural nos modos lança e da modificação da proporção entre oxigênio e gás natural (O2/GN) em um dos modos queimador do sistema de injeção de um forno elétrico a arco. Para tanto, foi realizado um teste estatístico dividido em quatro cenários no formato de projeto de experimentos (DOE). O cenário em que as modificações no modo queimador e nos modos lança foram aplicadas conjuntamente apresentou a maior redução no consumo de energia total (2,50%), impulsionada principalmente pelas reduções no consumo de gás natural (16,94%) e no consumo de energia elétrica de forno e forno-panela (-1,90%). Através da análise do carbono de vazamento de todas as corridas não foi possível afirmar que os ganhos em consumo de energia elétrica foram provenientes de uma maior oxidação de ferro da carga nas corridas. / Companies have been extensively focusing on cost reduction and productivity optimization in the last few years, independently of their levels of production or verticalization. The cost of production is basically controlled by two factors: the price and the consumption of raw and input materials. The price depends on the current conditions of the market and the capacity of the company to deal with its suppliers about the price to be paid. Due to that, it is very difficult to control this factor and for this reason, through the reduction in raw material and inputs consumption that companies can achieve their mission of becoming more profitable. In electric steelmaking, consumption of inputs plays an important role on the final billet cost, with particular emphasis to the energy consumption in the electric arc furnace, which can represent up to 30% of the operational cost in a melt shop. To quantify the contribution of different types of energy in the furnace, it is used the performance indicator of total energy consumption, which associates the heat of combustion of each type of energetic in order to use the unit kWh/t. The aim of this study was to evaluate the impact on the energy efficiency of the furnace, measured by the total energy consumption, reducing the flow of natural gas in lance modes and modifying the ratio between oxygen and natural gas (O2/NG) in one of the burner modes of the injection system in an electric arc furnace. Thus, a statistical test divided into four scenarios in the format of design of experiments (DOE) was conducted. The scenario in which the burner mode and lance mode modifications were applied together resulted in the greatest reduction in total energy (2,50%), driven especially by reductions in natural gas consumption (16,94%) and electrical energy consumption of furnace and ladle furnace (1,90%). Through the analysis of tapping carbon of all heats it was not possible to assert that gains in electrical energy were due to a higher oxidation of iron contained in the blend charged.

The benefits of an active lifestyle are undisputed, yet our understanding of the contribution of physical activity (PA) to the daily energy budget is limited. The prevailing model of a linear relationship between PA and total energy expenditure (TEE) has been challenged by models that predict an upper limit of TEE (constrained) or a compensatory decrease elsewhere in the budget in response to increased PA (compensated). The purpose of this study was to determine the equation of best fit between PA and TEE using linear and non-linear modeling in the light of existing models. Secondarily, we sought to explore relationships between PA and postulated means of behavioral (time sedentary) and physiologic (i.e. Immune, reproductive) compensation. We measured TEE in 57 healthy weight stable adults (18 to 58 yrs., F = 28) who ranged from being sedentary to ultra-endurance trained runners (0 to 78 mi/wk.) using the doubly labeled water technique and PA and sedentary time using a waist mounted triaxial accelerometer during the same 14-day period. We obtained fasting serum (albumin, cortisol, TNFα, C-reactive protein, free testosterone, TSH and T3), plasma (leptin) and whole blood (WBC with differential) concentrations. Using linear and non-linear modeling, we observed a positive linear relationship between PA (Vector Magnitude Counts per Minute ) and TEE (R2=0.313, Y = 1.427*X + 1930 and adjusted for fat free mass (FFM) R2=0.363, Y = 1.151*X + 2155). We identified no association between PA and RMR ( R2=0.015 and adjusted for FFM R2=0.010). In addition, we observed an association between higher PA and lower % time sedentary (R2=0.723). Although inconsistent, there was a general trend for higher PA but not TEE or its components to be associated with lower immune and reproductive biomarkers. These findings support a conventional linear model though intervention studies will be needed to further address this issue. / Doctor of Philosophy / The health benefits of being physically active are well known. At the same time there is much that is not understood about the relationship between physical activity and how much energy we spend in a day (total energy expenditure). It has been assumed for a long time that the amount of energy we spend is a simple matter of adding the calories burned at rest, digesting food, and exercising and as we exercise more we continue to add an equal number of calories to the daily budget. We call this the linear or additive model – energy spent increases in a straight line as physical activity increases. Because we have techniques for measuring total energy expenditure in people going about their usual lives that were not widely available until recently due to cost, scientists have developed new ideas about how increases in physical activity affect total energy expenditure. The constrained model suggests that there is a cap on how many calories we can burn in a day and that our bodies will save energy in other parts of the budget if our physical activity remains high enough to reach or exceed that cap. The second idea is called the compensated model like the constrained model predicts that the rate we spend energy slows down as we exercise more because the body has saved energy in other parts of the budget (compensation). Researchers don't know for sure if either of these models are correct, so we conducted a study to determine how physical activity and total energy expenditure are related and if our findings agree with either of these models. We were also interested in determining how physical activity is related to energy spent at rest (resting metabolic rate ) and energy spent being active (physical activity energy expenditure). Finally, we wanted to determine ways that the body might compensate. One way is to spend more time sedentary. Another way is to save energy on less urgent needs like the immune and reproductive systems. Our main goal was to create an equation that explain how higher levels of physical activity are related to total energy expenditure and other parts of the energy budget (RMR and physical activity energy expenditure). We also created equations that explain how physical activity is related to sedentary behavior and immune and reproductive markers in the blood. We recruited 57 male and female volunteers that represent a wide range of physical activity levels – from sedentary to ultra-endurance trained runners who routinely run as much as 80 miles per week. We measured the energy they spent and physical activity over 2 weeks. In our sample, we found that physical activity was related to total energy expenditure and physical activity energy expenditure in a linear way. We did not find a cap on the amount of energy spent (constraint). We found that participants who exercised more spent less time sedentary not more meaning that we did not find behavioral compensation. It is possible that there was compensation from the immune system because some of the markers of immune function were lower in people who were more physically active, but it was not consistent in all of the blood markers. A larger study using an exercise intervention is needed to assign causation to the correlation we found.

The main focus of my dissertation is the Modified Stochastic Sine-Gordon Equation: utt = 2uxx − ut − sin(|u|^(&gamma)) + b(u, du/dt)dW/dt where &gamma > 0 is the parameter of the power of non-linearity, &delta &ge 0 is the magnitude of non-linearity, &alpha> 0 be the damping parameter, and &sigma the diffusion intensity, on one dimensional domain. We analyze the properties of the solution of the SPDE by the eigenfunctions approach allowing us to truncate the infinite-dimensional stochastic system (i.e the SDEs of Fourier coefficients related to the SPDE), to control its energy, existence, uniqueness, continuity and stability. The analysis relies on the investigation of expected Lyapunov functional of the energy in terms of all system-parameters. We simulate the model with respect to all system-parameters to visualize our conclusions.

The Reverse Osmosis (RO) process has been considered to be one of the most widely utilised techniques for brackish water desalination for its capabilities to produce high-quality water. The RO process characterised by its low energy consumption compared to thermal distillation processes, leading to reduced overall water production cost. To systematically understand the transport phenomena of solvent and solutes via the membrane texture, several mathematical models were developed. This interestingly aids to conduct a huge amount of simulation and optimisation studies to judge the influence of control variables on the performance indexes and to adjust the key variables at optimum values to realise optimum production indexes. In this research, a specific accurate model for a single spiral wound RO process has been successfully developed and used to build accurate models for the multistage brackish water RO desalination process of two different designs. The robustness of the model developed was confirmed via validation against the experimental data collected from simple design of RO system and complicated design of RO system of Arab Potash Company (APC). This is followed by a thorough simulation of the RO process to explore the influence of operating conditions on the process performance indicators. Recently, several contributions were made in this thesis that specifically comprises the improvement of the original design of brackish water RO desalination process. The influence of a retentate recycle design is investigated on the process performance. Moreover, evaluation and minimisation of specific energy consumption (expressed in kWh/m3 of freshwater production) is carried out on the simple and complicated designs of RO process by implementing an energy recovery device. Also, the most suitable brand of membranes was explored for the RO system from a set of different brands of membrane to attain the highest-performance rejection at lowest energy consumption compared to the original membrane. Furthermore, a single optimisation framework was developed to mitigate the specific energy consumption of simple and complicated designs of brackish water RO desalination process. Finally, a thermodynamic limitations and exergy analysis of the complicated design of RO system are outlined via a thoroughly study to investigate the locations of high exergy destruction. These contributions were verified as they promoted the separation performance at a significant energy saving. / Mutah University, Jordan

O gasto energético total (GET) pode ser usado como medida da ingestão energética (IE). Existe um constante sub-relato da IE obtida por métodos de avaliação do consumo alimentar, mas poucos estudos o investigaram em nações em desenvolvimento. Objetivos: a) comparar a validade das estimativas de IE de um questionário de freqüência alimentar, três recordatórios alimentares e um diário alimentar de três dias, segundo a água duplamente marcada; b) determinar a influência da prática de atividade física, do índice de massa corporal e de fatores psicossociais no sub-relato e; c) comparar as taxas de sub-relato entre agrupamentos de padrões alimentares. Métodos: Sessenta e cinco mulheres responderam aos métodos de inquérito supracitados, a partir dos quais foi estimada a IE. O GET foi medido pela água duplamente marcada. A prática de atividade física, índice de massa corporal, escolaridade, renda, idade, conhecimento nutricional, insatisfação corporal, restrição dietética, compulsão alimentar e o desejo de aceitação social foram correlacionados ao sub-relato. Os padrões alimentares foram obtidos pela análise de cluster. Resultados: O GET foi de 2.622 ± 490 kcal, enquanto que a IE, mensurada respectivamente pelo recordatório, diário e questionário, foi de 2.078 ± 430 kcal; 2.044 ± 479 kcal e 1.984 ± 832 kcal. A proporção de sub-relatores foi de 24,6% para o recordatório, 29,2% para o diário e 53,8% para o questionário (p < 0,005). Os sub-relatores apresentaram menores médias de renda e escolaridade e maiores valores de idade, insatisfação corporal e desejo de aceitação social. O sub-relato foi mais comum no padrão alimentar mais frugal. Conclusão: Os três métodos de avaliação do consumo alimentar apresentaram erros sistemáticos, embora o questionário de freqüência alimentar tenha tido o pior desempenho. O sub-relato foi influenciado por diversos fatores psicossociais e variou conforme o padrão alimentar relatado, o que pode comprometer a avaliação do consumo / Total energy expenditure (TEE) may be used as a measure of energy intake (EI). There is a constant underreporting of EI obtained by dietary assessment methods, but few studies have investigated it in developing nations. Objectives: a) to compare the validity of EI estimates obtained by a food-frequency questionnaire, three diet recalls and a three-day food record; b) to determine the influence of physical activity, body mass index and psychosocial factors on underreporting and; c) to compare underreporting rates between dietary pattern\'s clusters. Methods: Sixty-five women completed the dietary assessment methods, which were used to estimate EI. TEE was measured by doubly labeled water. Physical activity practice, body mass index, education, income, age, nutritional knowledge, body dissatisfaction, dietary restraint, binge eating and social desirability were correlated to underreporting. Dietary patterns were obtained by cluster analysis. Results: TEE was 2,622 ± 490 kcal, while EI, measured respectively by the diet recall, food record and food-frequency questionnaire, was 2,078 ± 430 kcal; 2,044 ± 479 kcal and 1,984 ± 832 kcal. Proportion of underreporters was 24.6% (recall), 29.2% (record) and 53.8% (questionnaire) (p < 0.005). Underreporters had smaller income and education and greater age, body dissatisfaction and social desirability. Underreporting was more common in the \'frugal foods\' pattern. Conclusions: The three dietary assessment methods presented systematic errors, although the foodfrequency questionnaire had the worst performance. Underreporting was influenced by psychosocial factors and varied according the reported dietary pattern, which may compromise dietary assessment

Quantum Monte Carlo (QMC) methods are a class of stochastic techniques that can be used to compute the properties of electronic systems accurately from first principles. This thesis is mainly concerned with the development of trial wave functions for QMC. An extension of the backflow transformation to inhomogeneous electronic systems is presented and applied to atoms, molecules and extended systems. The backflow transformation I have developed typically retrieves an additional 50% of the remaining correlation energy at the variational Monte Carlo level, and 30% at the diffusion Monte Carlo level; the number of parameters required to achieve a given fraction of the correlation energy does not appear to increase with system size. The expense incurred by the use of backflow transformations is investigated, and it is found to scale favourably with system size. Additionally, I propose a single wave function form for studying the electron-hole system which includes pairing effects and is capable of describing all of the relevant phases of this system. The effectiveness of this general wave function is demonstrated by applying it to a particular transition between two phases of the symmetric electron-hole bilayer, and it is found that using a single wave function form gives a more accurate physical description of the system than using a different wave function to describe each phase. Both of these developments are new, and they provide a powerful set of tools for designing accurate wave functions. Backflow transformations are particularly important for systems with repulsive interactions, while pairing wave functions are important for attractive interactions. It is possible to combine backflow and pairing to further increase the accuracy of the wave function. The wave function technology that I have developed should therefore be useful across a very wide range of problems.

In this Thesis Project, the creation of a Low Energy building was examined in order to investigate how complex was to select the suitable parameters and systems of the dwelling, aiming to achieve the lowest possible energy consumption in one year period. All the technologies implemented into the system intended to be as energy efficient and profitable as possible. Another objective of this study was also to present the potential of the system to produce a part of the consumed energy, through renewable energy sources, approaching by this way also the standards of a Zero Energy Building. Firstly, the floor plan of the 150 m2 detached house, was drawn in the designing program AutoCAD. In continuation, this 2D floor plan was imported into the simulation program as well as all the initial input data so as for the Base model of the building to be created For the analysis of the building, the Simulation Program IDA ICE 4.7 was used. Gradually, alternations and adjustments were made into the Base model. Different models were created planning to analyze their results and conclude to the proper solution. All the simulations run for one year time period in order to present the total energy usage, system’s losses and demands in each case. In addition, as for the current study, the location of the construction was Athens, all building’s characteristics were chosen to comply with the Greek Regulation for Low Energy Buildings. Finally, through the procedure followed after having accomplished a series of simulations, the final annually energy demands managed to be within the required limits. / <p>Online Presentation</p>

O gasto energético total (GET) pode ser usado como medida da ingestão energética (IE). Existe um constante sub-relato da IE obtida por métodos de avaliação do consumo alimentar, mas poucos estudos o investigaram em nações em desenvolvimento. Objetivos: a) comparar a validade das estimativas de IE de um questionário de freqüência alimentar, três recordatórios alimentares e um diário alimentar de três dias, segundo a água duplamente marcada; b) determinar a influência da prática de atividade física, do índice de massa corporal e de fatores psicossociais no sub-relato e; c) comparar as taxas de sub-relato entre agrupamentos de padrões alimentares. Métodos: Sessenta e cinco mulheres responderam aos métodos de inquérito supracitados, a partir dos quais foi estimada a IE. O GET foi medido pela água duplamente marcada. A prática de atividade física, índice de massa corporal, escolaridade, renda, idade, conhecimento nutricional, insatisfação corporal, restrição dietética, compulsão alimentar e o desejo de aceitação social foram correlacionados ao sub-relato. Os padrões alimentares foram obtidos pela análise de cluster. Resultados: O GET foi de 2.622 ± 490 kcal, enquanto que a IE, mensurada respectivamente pelo recordatório, diário e questionário, foi de 2.078 ± 430 kcal; 2.044 ± 479 kcal e 1.984 ± 832 kcal. A proporção de sub-relatores foi de 24,6% para o recordatório, 29,2% para o diário e 53,8% para o questionário (p < 0,005). Os sub-relatores apresentaram menores médias de renda e escolaridade e maiores valores de idade, insatisfação corporal e desejo de aceitação social. O sub-relato foi mais comum no padrão alimentar mais frugal. Conclusão: Os três métodos de avaliação do consumo alimentar apresentaram erros sistemáticos, embora o questionário de freqüência alimentar tenha tido o pior desempenho. O sub-relato foi influenciado por diversos fatores psicossociais e variou conforme o padrão alimentar relatado, o que pode comprometer a avaliação do consumo / Total energy expenditure (TEE) may be used as a measure of energy intake (EI). There is a constant underreporting of EI obtained by dietary assessment methods, but few studies have investigated it in developing nations. Objectives: a) to compare the validity of EI estimates obtained by a food-frequency questionnaire, three diet recalls and a three-day food record; b) to determine the influence of physical activity, body mass index and psychosocial factors on underreporting and; c) to compare underreporting rates between dietary pattern\'s clusters. Methods: Sixty-five women completed the dietary assessment methods, which were used to estimate EI. TEE was measured by doubly labeled water. Physical activity practice, body mass index, education, income, age, nutritional knowledge, body dissatisfaction, dietary restraint, binge eating and social desirability were correlated to underreporting. Dietary patterns were obtained by cluster analysis. Results: TEE was 2,622 ± 490 kcal, while EI, measured respectively by the diet recall, food record and food-frequency questionnaire, was 2,078 ± 430 kcal; 2,044 ± 479 kcal and 1,984 ± 832 kcal. Proportion of underreporters was 24.6% (recall), 29.2% (record) and 53.8% (questionnaire) (p < 0.005). Underreporters had smaller income and education and greater age, body dissatisfaction and social desirability. Underreporting was more common in the \'frugal foods\' pattern. Conclusions: The three dietary assessment methods presented systematic errors, although the foodfrequency questionnaire had the worst performance. Underreporting was influenced by psychosocial factors and varied according the reported dietary pattern, which may compromise dietary assessment

Background: The level of activity in an individual can be the difference between health and illness. Physical inactivity can cause diseases such as osteoporosis and type-2 diabetes. It has been reported that children live an increasingly inactive life, with less than the recommended a total of 60 minutes daily for children and adolescents of 6-17 years of age. Objective: The objective was to compare two activity diaries and how the results correspond to measurements by an activity meter. Material and methods: This study included 12 children who each carried an activity meter for four days to measure Total Energy Expenditure. In parallel, they filled in two different activity diaries. In the diaries two different calculation methods were used, with a Physical Activity Ratio value or a Metabolic Equivalent of Task value which then was inserted into equations to calculate Total Energy Expenditure. Anthropometric measurements were obtained by use of a stadiometer, a caliper and a bioimpedance scale. Results: The results from the Physical Activity Ratio diary indicated a better match with the results from the activity meter. Conclusions: Between the two diaries significant difference in how the activities were estimated were found, where an overestimation could be seen in the diary that used the Metabolic Equivalent of Task. Differences could also be seen between the activity meter and both diaries, also here the difference were bigger with the Metabolic Equivalent of Task diary. The Physical Activity Ratio diary was better matched with the activity meter.