A manutenção da qualidade do solo como um recurso natural vital à humanidade tem impulsionado a pesquisa sobre a dinâmica ambiental de resíduos de antibióticos veterinários no ambiente. Os processos de sorção, degradação e lixiviação da sulfadiazina (SDZ) foram avaliados em quatro solos com atributos físico-químicos distintos, conforme o uso de técnicas radiométricas e os protocolos da OECD para pesticidas. Os coeficientes de sorção (Kd) da SDZ variaram de baixo a muito alto (2,6 a 80 L kg-1). O seu baixo potencial de dessorção (< 24,2% do sorvido ou < 12,1% do aplicado) ratifica a existência de mecanismos específicos envolvidos na sorção da SDZ, afora as interações eletrostáticas e a partição hidrofóbica apontadas pelos estudos prévios. Em concentrações residuais próximas às encontradas em campo (??84 ?g kg-1), o potencial de sorção da SDZ foi consideravelmente maior do que em altas concentrações. A dissipação da SDZ foi rápida em todos os solos (t1/2 < 2,7 dias) e a formação de resíduos ligados foi a principal via de dissipação, correspondendo a > 78% do aplicado após 7 dias. A taxa média de mineralização foi < 3% do aplicado. A presença do antibiótico não impactou a biomassa do solo, indicando que em doses crônicas os efeitos sejam imperceptíveis em curto prazo. Apesar do potencial de mobilidade, a SDZ apresentou baixo potencial de lixiviação nos solos (< 0,11% do aplicado). Já a redistribuição da SDZ foi maior no perfil dos solos recém-aplicados do que nos envelhecidos e a grande maioria permaneceu nos primeiros 5 cm (> 95 % do aplicado). Nos solos envelhecidos, a sua mobilidade foi praticamente nula (0,06% do aplicado). Os resultados da pesquisa contribuem para elucidar a dinâmica de contaminantes orgânicos em solos intemperizados e ácidos de regiões tropicais, o que poderá auxiliar modelos de avaliações de risco, ações de mitigação, entre outros. / The soil quality as a vital resource for humanity has driven research on the occurrence, environmental fate and behavior of antibiotic residues in the environment. Sorption, leaching and degradation tests were performed on four soils with distinct physic-chemical attributes with 14C-sulfadiazine, following guidelines developed by OECD (USA) for laboratory studies. As the development of research on the subject has its origins in temperate countries, the soil and climatic conditions occurring in the tropics resulted in variations in the dynamic of sulfadiazine, mainly due to conditions of weathered and acidize.The results showed higher Kd (from 3, 5 to 80 L kg-1) for the residual concentration detected in monitoring studies, rapid dissipation (DT 50 between 2 and 3 days) and reduced leaching potential, in contrast with rates reported in the literature. The formation of bound residues was the major route of dissipation in all soils, reaching values between 78 % and 89 % of the total in just 7 days, whereas the mineralization did not exceed 1.5% throughout the experiment. The analysis of the variation of microbial-biomass carbon as an negative effect of antibiotic, present no difference with the content in the control, as reported by several studies that argue that the effects of chronic doses are imperceptible in short term. Although the knowledge about processes transformation of organic chemicals in soils is very divergent, laboratory tests contributed to a first elucidation about environmental of antibiotic residues, contributing to the improved performance of models to compose risk assessments and mitigation actions in tropical soils, for example.

Objetiva-se discutir e explorar as consequências da conservação do momento angular em situações físicas que apresentem dissipação de energia. Frequentemente, sistemas mecânicos dissipativos são omitidos nas formulações matemáticas da mecânica clássica. No entanto, a conservação da energia mecânica é uma idealização drasticamente incompatível, a longos períodos de tempo, com a maioria das situações reais. Apesar de parecer controversa, esta abordagem é compreensível desde que é incluída na dissipação toda a complexidade dos sistemas mecânicos, os quais não podemos modelar completamente. Espera-se assim que os resultados obtidos sejam parcialmente comprovados em experimentos, sendo que a discrepância é atribuída à parte desconhecida do fenômeno, que muitas vezes é considerada irrelevante para fins práticos. Devido à mencionada complexidade de fenômenos dissipativos, a postura adotada nesta dissertação foi analisar específicos exemplos, de natureza distinta, simplificados, que apresentem as duas propriedades em questão. Concentrou-se especialmente no problema de dissipação de energia em corpos deformáveis na ausência de estímulos externos. / The goal of this work is to study physical systems where angular momentum is a conserved quantity while energy is dissipated. It is a common practice among people working on classical mechanics to neglect energy dissipation. While this hypothesis leads to beautiful mathematical theories, it is strongly violated by the majority of real world systems. The physical complexity of the many ways in which energy is dissipated turns the mathematical modelling of dissipative forces troublesome. There is essentially no general mathematical model for dissipative forces in good agreement with a wide range of experiments. This is in contrast to the very few accepted conservative force models: gravity, elasticity and magneto-electricity. The dissipative force model usually varies among the various physical situations. So, in this work several systems where energy is dissipated while angular momentum is conserved will be considered. The main example will be the motion of a deformable body free from external forces and torques.

Esta dissertação trata da hidráulica da queda livre em canal de seção retangular. A análise bibliográfica do tema está calcada nos trabalhos pioneiros, nos clássicos e nos recentes. Com base nos princípios da Física: Conservação de Massa, Quantidade de Movimento, e Primeira Lei da Termodinâmica, foi desenvolvido um modelo matemático para a queda livre. O modelo proposto, após ser analisado do ponto de vista de sua consistência, foi validado em comparações com resultados fornecidos por outros pesquisadores, geralmente com modelos empíricos (ou semi-empíricos), ajustados a dados experimentais. Os resultados obtidos pelo modelo matemático proposto nesta dissertação, correspondem a boas estimativas das grandezas envolvidas nos escoamentos em queda livre, o que credencia o modelo proposto como uma ferramenta apropriada para projetos em engenharia hidráulica, principalmente quando se tem em conta que a queda livre é o mecanismo de dissipação mais presente na natureza. / This study addresses free fall hydraulics in rectangular channel section. References were based on not only earlier studies, but also on classical and most recent ones. Based on principles of Physics, such as mass conservation, momentum and the First Law of Thermodynamics, a mathematical model has been developed as an example of free fall hydraulic. After extensive consistency analyses the proposed model has been validated by comparing different results furnished by other researchers, generally based on empirical or semiempirical treatment adjusted to experimental data. Results obtained from the mathematical model proposed here correspond to good estimates of greatnesses involved in the free overfall and that turns the proposed model into an adequate tool for Hydraulic Engineering projects, especially when we all know free overfall is the most common dissipation mechanism in Nature.

Beach grain size plays a major role in controlling beach slope and sediment transport rates and is a crucial criterion in selecting the appropriate fill material for beach nourishment. Yet, little is known about how and why beach grain size (and sorting) varies both spatially and temporally on high-energy sandy beaches. Therefore, in this PhD research project, the presence, magnitude and predictability of any spatio-temporal sediment variability was investigated on a number of contrasting high-energy (average significant wave height = 0.8 to 3.5 m), predominantly macrotidal (MSR = 3.1 – 6.2 m), sandy (0.26 – 0.64 mm) beach sites around the southwest peninsula of the United Kingdom (UK). The spatial extent of the data collected ranges from regional (one off snapshot of the sediment conditions on 53 beaches over 485 km of coastline) to local scales (repeated high-resolution samples from across the inter- and subtidal zone of a single high-energy sandy beach; Perranporth, UK). The temporal scales of the sampling ranges from tidal scale (~12 hours) up to monthly (long-term monitoring since 2008). A combination of traditional and modern field data collection methods has provided new insights into the sediment dynamics of sandy beaches. Surface and 0.25 m core sediment samples from the 53 beaches around the southwest UK and high-resolution digital measurements with longer 1 m sand cores from the intertidal zone, plus grab samples from the subtidal zone, at Perranporth, indicated the presence of three quasi-permanent spatial trends. On all sandy beaches, surface sediments became coarser (and better sorted) in the seaward direction across the intertidal zone. Peak sediment sizes were observed on the lower beach around mean low water springs, which were an average 19% coarser (and 8% better sorted) than sediments sampled on the upper intertidal beach. Sediment size (and sorting) also increased (improved) with distance down the sediment column over the top 0.25 m to 1 m. Peak sediment sizes at depth were an average 16% coarser (and 16% better sorted) than surface sediments. In the subtidal zone, surface sediments became finer and poorer sorted with increasing offshore distance. Minimum sediment size occurred on the subtidal bar crest and were an average 21% finer (and 51% poorer sorted) than the lower beach sediments and 5% finer (and 38% poorer sorted) than upper beach sediments. The coarsest sediments were usually the best sorted at all locations. The intertidal coarsening was deterministically linked to the location and amount of breaking wave-induced turbulence. The peak sediment sizes (and sorting) on the lower beach correlated with the location of peak wave dissipation (sediment size to amount of wave dissipation, r2 = 0.86) and the finer sediment sizes on the upper beach and bar were coincident with reduced amounts of wave dissipation in these regions. Long-term seasonal monitoring of the surface sediments at Perranporth indicated a background seasonality, where the winter months were an average 35% coarser and 22% better sorted than samples collected in summer. This seasonal pattern was punctuated by episodic storm events that promoted a significant coarsening (up to 112% in the extreme winter storms of 2014) of the surface sediments and significant beach erosion up to 175 m3/m. An empirical model forced by the degree of disequilibrium between an instantaneous and antecedent (weighted average) wave steepness time series was able to capture up to 86% of the sediment grain size and sorting variability, incorporating both the seasonal and storm driven change. The same model, applied to daily observations of sediment size and sorting changes was able to explain 72% of the variability. A conceptual model is proposed that extends the cross-shore sediment transport shape functions to include the various sediment (size and sorting) responses alongside the morphodynamic evolution during persistently high and low wave steepness conditions. Under high steepness waves, the finer material is preferentially removed from the lower intertidal beach, leaving behind coasrer sediments. This fine material is transported to the subtidal bar, which becomes finer (and more poorly sorted) inversely with the coarsening (and improved sorting) of the intertidal zone sediments. Under low steepness waves, this fine material is returned from the bar to the intertidal beach. This work provides a detailed, quantitative insight into the magnitude of sediment grain size and sorting changes exhibited by sandy beaches on a number of spatial and temporal scales. Several consistent trends were observed on a range of sandy beaches despite their different environmental conditions and geological histories. This improved understanding of sediment grain size and sorting changes on beaches will hopefully aid future research efforts and ensure that this fundamental aspect of coastal science is not overlooked or oversimplified.

In 2012, plasma figuring was proven to be an alternative solution for the fabrication of large scale ultra-precise optical surfaces. Indeed, plasma figuring was successfully demonstrated on a metre class glass surface. The process was exceptionally rapid but residual errors were observed. This thesis addresses this issue by proposing an enhanced tool that provides a highly collimated plasma jet. The enhanced tool is characterized by a targeted material removal footprint in the range 1 to 5 mm FWHM. The energy beam is provided by an Inductively Coupled Plasma (ICP) torch equipped with a De-Laval nozzle. This thesis focuses on characterization and optimisation of the bespoke plasma torch and its plasma jet. Two research investigations were carried out using both numerical and experimental approaches. A novel CFD model was created to analyse and understand the behaviour of high temperature gas in the De-Laval nozzle. The numerical approach, that was based on appropriate profiles of temperature and velocity applied to the nozzle inlet, led to a significant reduction of computational resources. This model enabled to investigate the aerodynamic phenomena observed from the nozzle inlet up to the processed surface. Design rules and the effect of changing nozzle parameters were identified. Sensitivity analysis highlighted that the throat diameter is the most critical parameter. A challenging power dissipation analysis of the plasma torch was carried out. Temperature and flow rate in key components of the torch were measured. Experimental results enabled to calculate the power dissipation values for RF power up to 800 W and for the entire series of designed nozzles. This work enabled to scientifically understand the power dissipation mechanism in the bespoke ICP torches. In addition, by comparing the intensity of the power dissipation values, one nozzle was clearly identified as being more capable to provide a highly efficient plasma jet.

The continuing requirement for computational processing power, multi-functional devices and component miniaturization have emphasised the need for thermal management systems able to maintain the temperature at safe operating condition. The thermal management industry is constantly seeking for new cutting edge, efficient, cost effective heat transfer enhancement technologies. The aim of this study is to utilize the electron beam treatment for the improvement of the heat transfer area in liquid cooled plates and experimentally evaluate the performance. Considering the complexity of the technology, this thesis focuses on the design and production of electron beam enhanced test samples, construction of the test facility, testing procedure and evaluation of thermal and hydraulic characteristics. In particular, the current research presented in this thesis contains a number of challenging and cutting edge technological developments that include: (1) an overview of the semiconductor industry, cooling requirements, the market of thermal management systems, (2) an integral literature review of pin-fin enhancement technology, (3) design and fabrication of the electron beam enhanced test samples, (4) upgrade and construction of the experimental test rig and the development of the test procedure, (5) reduction of the experimental data and analysis to evaluate thermal and hydraulic performance. The experimental results show that the capability of the electron beam treatment to improve the thermal efficiency of current untreated liquid cooled plates is approximately three times. The highest heat transfer rate was observed for the sample S3; this is attributed to the irregularities of the enhanced structure, which improves the heat transfer area, mixing, and disturbs the thermal and velocity boundary layers. Enhancement of heat transfer for all three samples was characterised by an increase of pressure drop. The electron beam enhancement technique is a rapid process with zero material waste and cost effective. It allows thermal management systems to be produced smaller and faster, reduce material usage, without compromising safety, labour cost or the environment.

In this thesis, we produce a rigorous and quantitative analysis of the errors introduced by finite difference schemes into strong constraint 4D-Variational (4D-Var) data assimilation. Strong constraint 4D-Var data assimilation is a method that solves a particular kind of inverse problem; given a set of observations and a numerical model for a physical system together with a priori information on the initial condition, estimate an improved initial condition for the numerical model, known as the analysis vector. This method has many forms of error affecting the accuracy of the analysis vector, and is derived under the assumption that the numerical model is perfect, when in reality this is not true. Therefore it is important to assess whether this assumption is realistic and if not, how the method should be modified to account for model error. Here we analyse how the errors introduced by finite difference schemes used as the numerical model, affect the accuracy of the analysis vector. Initially the 1D linear advection equation is considered as our physical system. All forms of error, other than those introduced by finite difference schemes, are initially removed. The error introduced by `representative schemes' is considered in terms of numerical dissipation and numerical dispersion. A spectral approach is successfully implemented to analyse the impact on the analysis vector, examining the effects on unresolvable wavenumber components and the l2-norm of the error. Subsequently, a similar also successful analysis is conducted when observation errors are re-introduced to the problem. We then explore how the results can be extended to weak constraint 4D-Var. The 2D linear advection equation is then considered as our physical system, demonstrating how the results from the 1D problem extend to 2D. The linearised shallow water equations extend the problem further, highlighting the difficulties associated with analysing a coupled system of PDEs.

Made available in DSpace on 2017-07-21T19:26:10Z (GMT). No. of bitstreams: 1 Regiane Aparecida.pdf: 1187901 bytes, checksum: b637bcaefc952d1ee86519999fc34121 (MD5) Previous issue date: 2007-06-25 / The implementation of processes of Quantum Computation as well as the transmission and quantum information control in realistic physical systems, must take in account the effects of the coupling of the systems with the environment, represented by thermal reservoirs. In this work it is considered the study of the effects of the environment in the quantum properties of each modes in a system of weakly coupled bosonics ones (the electromagnetic modes in the coupled cavities). It is applied an alternative method, based on effective non Hermitian Quadratic Hamiltonian, in order to understand how to determine the time evolution of the Wigner function of the system under study; the technique of Wigner funtion propagator and a specific solution is presented. In addition, the time evolution of the non symmetric second moments is exactly determined for the special case of initial general Gaussian states for both modes, in the presence of thermal reservoir. It is analyzed as the squeezing and the purity of each mode as well as the entanglement among them evolve in time under dissipation, compared to the case of reservoir absence. For this purpose, it is briey considered some techniques applied the study of the quantum information and measures of quantum correlations for quantum multipartite systems, here only applied to a bipartite system. This work is concluded with some numerical analysis of the quantum properties in terms of initial state parameters and gives some future perspective in order to generalize our results. / A implementação de processos em Computação Quantica bem como a transmissãoo e controle de informação quantica em sistemas fisicos realistas, precisam levar em consideração os efeitos do acoplamento do sistema com o ambiente, representado por reservatórios térmicos. Neste trabalho considera-se o estudo do efeito do ambiente nas propriedades quânticas de cada modo em um sistema de modos bosônicos fracamente acoplados (os modos eletro-magnéticos na cavidade acoplada). É aplicado um méetodo alternativo, baseado no Hamil-toniano Quadrático efetivo não Hermitiano, afim de compreender como determinar a evolução temporal da função de Wigner do sistema sob estudo; é apresentada a técnica do propagador da função de Wigner e a solução especifica. Além disso, a evolução temporal dos segundos momentos não-simetrizados é determinada exatamente para o caso especial de estados iniciais gerais Gaussianos para ambos os modos, na presença do reservatório térmico. Analisa-se como a compressão e a pureza de cada modo bem como o emaranhamento entre eles evoluem no tempo sob dissipação, comparado ao caso da ausência de reservatório. Para esse propósito, são brevemente consideradas algumas técnicas aplicadas ao estudo da informação quântica e medidas de correlação quântica para sistemas quânticos de muitas partes, sendo aqui somente aplicado a sistemas de duas partes. Este trabalho é concluido com uma análise numérica das propriedades quânticas em termos dos parâmetros do estado inicial e algumas perspectivas futuras são apresentadas afim de generalizar estes resultados.

O presente trabalho apresenta a análise térmica do fenômeno de fermentação de cerveja com o objetivo de quantificar a energia liberada durante o processo e avaliar o comportamento do campo de temperaturas do fermentando. É adotada uma metodologia que reúne abordagens teóricas e experimentais, aplicadas a um processo completo de fermentação. O calor dissipado durante a fermentação é calculado por equações presentes na literatura, tendo como entrada a taxa de conversão de glicose e produção de CO2. Essas taxas são calculadas pelas concentrações de glicose medidas de amostras retiradas durante ensaios planejados. A dissipação é usada como entrada em dois modelos térmicos para o cálculo do campo de temperaturas do fermentando. As temperaturas calculadas são superiores àquelas monitoradas experimentalmente, com diferenças de até 78%. Esse comportamento embasa a proposta de uma equação de ajuste do calor liberado durante a fermentação. A equação proposta indica que é liberado 38 kJ por mol de glicose convertido, neste estudo a taxa de dissipação térmica atinge valor máximo de 11,41 Wm-3 e a energia total dissipada é de 385 kJ para produzir 40 litros de cerveja. O ajuste mostrou-se satisfatório, as temperaturas máximas e os campos de temperaturas calculados apresentaram valores equivalentes aos valores experimentais. / The present study carry out a thermal analysis of beer fermentation process which aims to quantify the energy released during the process and evaluate the temperature field, using a methodology that brings together theoretical and experimental approaches. The heat dissipated during the fermentation is calculated by equations reported in the literature, with the conversion rates of glucose and CO2 production as input. These rates are calculated using the glucose concentrations measured of samples taken during tests. The dissipation is used as input in two thermal models for the calculation of temperature field. The calculated temperatures are higher than those monitored experimentally, with differences up to 78%. It supports the proposal of an adjusted equation for heat release of beer fermentation. The proposed equation indicates that 38 kJ per mol of converted glucose is released. In this study, the thermal dissipation rate reaches a maximum value of 11.41 Wm-3 and the total energy dissipated is 385 kJ for producing 40 liters of beer. The adjustment is satisfactory, the maximum temperatures and the temperature fields calculated are equivalent to the experimental values.

Esta tese objetiva caracterizar o escoamento provocado pela incidência de um jato vertical em um fundo plano, descrevendo assim as características médias e flutuantes das pressões a partir da investigação experimental. O modelo utilizado é composto por um jato retangular posicionado, perpendicularmente, a uma distância de 0,92 m do fundo plano de um canal. Utilizando transdutores de pressão instalados na posição de incidência do jato, adquiriu-se os valores de pressão “instantânea” a uma frequência de 128 Hz durante 10 minutos. Foram ensaiadas cinco (5) vazões: 25 l/s (Fr1 = 7,12), 30 l/s (Fr1 = 8,51), 36,6 l/s (Fr1 = 10,35), 42,7 l/s (Fr1 = 12,12) e 50l/s (Fr1 = 14,23), além de vinte (20) diferentes espessuras de colchão d'água. Com os dados de pressão, efetuou-se análises no domínio do tempo, da frequência e da posição. No domínio do tempo, analisou-se a variação dos parâmetros estatísticos essenciais (média, desvio padrão, assimetria e curtose) bem como a identificação de valores máximo e mínimos das pressões. No domínio da frequência, procurou-se avaliar por meio da análise espectral a identificação de frequências significativas associadas à energia macroturbulenta. No que tange à análise no domínio da posição buscou-se analisar a faixa de influência do jato junto ao fundo, a região de subpressões e o alcance das pressões dinâmicas. Outro aspecto importante abordado é a apresentação dos resultados em gráficos adimensionalizados, o que confere ao estudo um caráter geral dentro da faixa de valores ensaiados. Os resultados definem um colchão mínimo de água da ordem de 3 vezes a altura crítica do escoamento, para o amortecimento das pressões dinâmicas. A análise dos momentos estatísticos demonstra que a distribuição das pressões não segue a distribuição normal. Dentro disso, estão disponibilizados coeficientes estatísticos de probabilidade para a determinação das pressões extremas. Ainda, estão definidas quatro zonas a jusante do impacto do jato: Zona I - região do impacto, Zona II - reflexão do jato, Zona III - Acomodação do escoamento e por fim, a Zona IV - caracterizada pelo fim da influência do jato. Além disso, uma análise deste escoamento sob a perspectiva da formação de um ressalto hidráulico é realizada, indicando que apenas os parâmetros utilizados, não descrevem o escoamento como tal. Esta tese é produto da parceria entre Laboratório de Obras Hidráulicas do Instituto de Pesquisas Hidráulicas da Universidade Federal do Rio Grande do Sul (LOH/IPH/UFRGS) e o Laboratório de Hidráulica Experimental e Recursos Hídricos de Furnas Centrais Elétricas S. A. (LAHE/FURNAS). / This thesis aims to characterize the flow prompted by the incidence of a vertical jet on a flat bottom, thus describing the mean and floating characteristics of the pressures from the experimental investigation. The model used is comprised of a rectangular jet positioned perpendicularly at a distance of 0.92 m from the flat bottom of a channel. Using pressure transducers installed in the jet incidence position, the "instantaneous" pressure values were acquired at a frequency of 128 Hz for 10 minutes. Five (5) discharges were tested: 25 l/s (Fr1 = 7.12), 30 l/s (Fr1 = 8.51), 36.6 l/s (Fr1 = 10.35), 42.7 l/s (Fr1 = 12.12) and 50 1/s (Fr1 = 14.23), as well as twenty (20) different waterbed thicknesses. The pressure data were analyzed in terms of time, frequency and position domains. In the time domain, the variation of the essential statistical parameters (mean, standard deviation, asymmetry and kurtosis) was analyzed, as well as the identification of maximum and minimum pressure values. In the frequency domain, it was sought to assess, by means of the spectral analysis, the identification of significant frequencies associated with macroturbulent energy. Regarding the analysis in the position domain, this study aimed to analyze the range of influence of the jet near the bottom, the region of subpressions and the reach of the dynamic pressures. Another important aspect is the presentation of the results in dimensionless graphs, which grants the study a general character within the range of values tested. The results define a minimum waterbed of the order of 3 times the critical height of the flow for the damping of the dynamic pressures. Statistical moments analysis shows that the distribution of pressures does not follow the normal distribution. Therein, probability statistical coefficients are available for the determination of extreme pressures. Also, four zones are defined downstream of the impact of the jet: Zone I - region of impact, Zone II - reflection of the jet, Zone III - accommodation of the flow and, finally, Zone IV - characterized by the end of the influence of the jet. Furthermore, an analysis of this flow from the perspective of the formation of a hydraulic jump is conducted, indicating that the parameters used alone do not describe the flow as such. This thesis is a product of the partnership between the Hydraulic Works Laboratory of the Hydraulic Research Institute of the Federal University of Rio Grande do Sul (LOH/IPH/UFRGS) and the Laboratory of Experimental Hydraulics and Hydraulic Resources of Furnas Centrais Elétricas SA (LAHE/FURNAS).