This Doctoral thesis is focused on optimizing the design of modern wooden structures. Because this theme is very comprehensive, the work analyzes the distribution of moisture through the building envelope in detail. In the introduction are summarizes the knowledge of the physical processes in the constructions, there are also the properties of wood as a material and basic information about system of timber structures. The next section describes used methodology and experimental measurements realized on an experimental timber house EXDR1. There is specified the principle of measurement based on the SWOT analysis, the use measuring devices or possible solutions in the field of numerical modeling too. Main results and conclusions of the dissertation for technical practice including possibilities of further research are summarized in the final section.

No description available.

The two-phase MD technique employed in this work determines the liquid and vapor phase densities from a histogram of molecular densities within phase clusters in the simulation cell using a new Monte Carlo (MC) sampling method. These equilibrium densities are then fitted in conjunction with known critical-point scaling laws to obtain the critical temperature, and the critical density. This MC post-processing method was found to be more easily implemented in code, and it is efficient and easily applied to complex, structured molecules. This method has been successfully applied and benchmarked for a simple Lennard-Jones (LJ) fluid and a structured molecule, propane. Various degrees of internal flexibility in the propane models showed little effect on the coexisting densities far from critical point, but internal flexibility (angle bending and bond vibrations) seemed to affect the saturated liquid densities in the near-critical region, changing the critical temperature by approximately 20 K. Shorter cutoffs were also found to affect the phase dome and the location of the critical point. The developed MD+MC method was then used to test the efficacy of two all-atom, site-site pair potential models (with and without point charges) developed solely from the energy landscape obtained from high-level ab initio pair interactions for the first time. Both models produced equivalent phase domes and critical loci. The model's critical temperature for methanol is 77 K too high while that for 1-propanol is 80 K too low, but the critical densities are in good agreement. These differences are likely attributable to the lack of multi-body interactions in the true pair potential models used here. Lastly, the transferability of the ab initio potential model was evaluated by applying it to 1-pentanol. An attempt has been made to separate the errors due to transferability of the potential model from errors due to the use of a true-pair potential. The results suggested a good level of transferability for the site-site model. The lack of multi-body effects appears to be dominant weakness in using the generalized ab initio potential model for determination of the phase dome and critical properties of larger alcohols.

The author presents the successful development of an on-chip, monolithic, integrated rubidium vapor-cell. These vapor-cells integrate ridge waveguide techniques with hollow-core waveguiding technology known as Anti-Resonant Reflecting Optical Waveguides (ARROWs). These devices are manufactured on-site in BYU's Integrated Microelectronic Laboratory (IML) using common silicon wafer microfabrication techniques. The ARROW platform fabrication is outlined, but the bulk of the dissertation focuses on novel packaging techniques that allow for the successful introduction and sealing of rubidium vapor into these micro-sized vapor-cells. The unique geometries and materials utilized in the ARROW platform render common vapor-cell sealing techniques unusable. The development of three generations of successful vapor-cells is chronicled. The sealing techniques represented in these three generations of vapor-cells include high-temperature epoxy seals, cold-weld copper crimping, variable pressure vacuum capabilities, indium solder seals, and electroplated passivation coatings. The performance of these seals are quantified using accelerated lifetime tests combined with optical spectroscopy. Finally, the successful probing of the rubidium absorption spectrum, electromagnetically induced transparency, and slow light on the ARROW-based vapor-cell platform is reported.

No description available.

To design high pressure fuel system components that resist wear and scuffing failure when operated in low viscosity fuels, a comprehensive study on the tribological performance of various existing coating materials is necessary. This thesis aims to provide the relative performance of a variety of coating materials across different fuel environments by testing them in conditions that model those experienced in fuel pumps. The relative performance of these coatings are then indexed across a variety of material properties, including hardness, elastic modulus, wettability, and the interaction between the surface and the various types of fuel molecules.

[pt] A determinação de parâmetros de interação precisos para equações de estado (EdE) em sistemas aquosos de aminas são cruciais para desenvolver modelos termodinâmicos em processos da engenharia química. O sistema binário de Nmetildietanolamina (MDEA) e água na purificação do biogás foi avaliado usando as abordagens 𝜑 – 𝜑 e 𝛾 – 𝜑, EdE de Peng–Robinson clássico com a regra de mistura não aleatória e EdE Peng–Robinson com a regra de mistura Wong-Sandler, para otimizar o fator acêntrico, ω, de componentes puros, e os parâmetros de interação binária, 𝑘𝑖𝑗. Os parâmetros de interação 𝑢𝑖𝑗 das EdE que incorporam o modelo UNIQUAC, como a abordagem γ – φ e a regra de mistura de Wong-Sandler também foram otimizados. Esses parâmetros foram avaliados usando um algoritmo de pressão de bolha reativa, codificação MATLAB e minimização de funções objetivas relacionadas ao desvio médio absoluto, AAD, entre dados experimentais e calculados em diferentes temperaturas. Os ω calculados de água, CO2 e MDEA foram 0,3275, 0,2039 e 1,0133, respectivamente, com AAD inferior aos valores da literatura. A abordagem 𝜑 − 𝜑 com EdE clássica de Peng–Robinson com regra de mistura Wong– Sandler foi mais adequada para o binário MDEA – H2O, resultando em 𝑢12 0 = −234.2841, 𝑢12 𝑇 = 1.0499, 𝑢21 0 = 266.4326, 𝑢21 𝑇 = 0.1966, 𝑘𝑖𝑗 = −0.0715, com pressão de vapor AAD% = 6,57% e composição AAD% = 17,51%. Devido à natureza altamente não ideal do sistema binário CO2 – H2O, nem as abordagens φ – φ ou γ – φ usando as EdE selecionadas resultaram em diagramas precisos de pressão de ponto de bolha para o equilíbrio vapor – líquido (VLE). / [en] Determining interaction parameter for equations of state (EOS) of water – amines systems are crucial to develop accurate models in chemical engineering processes. The binary system of N-methyldiethanolamine (MDEA) and water in biogas purification was evaluated using both φ – φ and γ – φ approaches, classic Peng–Robinson with the empirical “non-random” mixing rule and Peng–Robinson with the Wong-Sandler mixing rule EOS to optimize pure components acentric factor, ω, and binary interaction parameters, 𝑘𝑖𝑗. The interaction parameters 𝑢𝑖𝑗 from EOS that incorporate UNIQUAC model, such as γ – φ approach and Wong-Sandler mixing rule were optimized as well. These parameters were evaluated using a bubble pressure algorithm, MATLAB coding and minimization of objective functions related to absolute average deviation, AAD, between experimental and calculated data at different temperatures. The calculated ω of water, CO2 and MDEA were 0.3275, 0.2039 and 1.0133 respectively with lower AAD than literature values. The 𝜑−𝜑 approach classic Peng–Robinson with Wong – Sandler mixing rule EOS was better suited for the MDEA – H2O binary, resulting in as 𝑢120=−234.2841, 𝑢12𝑇=1.0499, 𝑢210=266.4326, 𝑢21𝑇=0.1966, 𝑘𝑖𝑗=−0.0715, with vapor pressure AAD% = 6.57% and composition AAD% = 17.51%. Due to the highly non-ideal nature of the CO2 – H2O binary system, neither φ – φ or γ – φ approaches using the selected EOS resulted in accurate vapor – liquid equilibrium (VLE) bubble point pressure diagrams.

No description available.

[pt] O objetivo do trabalho foi desenvolver métodos analíticos capazes de especiar mercúrio, determinando metilmercúrio (CH3Hg), etilmercúrio (CH3CH2Hg), mercúrio inorgânico (Hg2+, Hg0), em água de produção (AP), e tiomersal (C9H9HgNaO2S), em urina e em efluente de uma indústria farmacêutica. Apesar de existir muitos métodos para quantificar espécies de mercúrio, poucos estudos abordam a especiação em AP, amostras conhecidas por ter altos teores de óleo e sal. Além disso, o uso de nanomateriais, como pontos quânticos de grafeno (GQDs), sozinho ou dopados de nanopartículas de dióxido de titânio (GQDs-TiO2 NPs), foram usados como agentes fotocatalíticos para produzir o mercúrio elementar detectado. As técnicas analíticas utilizadas para a detecção de mercúrio total e para especiação por mercúrio foram espectrometria de absorção atômica com vapor frio em cela multipasso (multipath-CV-AAS) e espectrometria de fluorescência atômica com vapor frio acoplado ao sistema de cromatografia gasosa (GC-CV-AFS). No primeiro trabalho, a foto-degradação do tiomerosal foi alcançada utilizando luz visível e GQDs, obtidos a partir da hidroexfoliação de ácido cítrico e glutationa, como foto-catalisador. O Hg0 gerado (usando condições experimentais ajustadas) foi detectado por multipath-CV-AAS, permitindo a quantificação de tiomersal em concentrações equivalentes a 20 ng L-1, mesmo em amostras complexas como efluentes aquosos da indústria farmacêutica e em urina. A cinética de reação (pseudo-primeira ordem com k = 0,11 min-1) foi determinada. O segundo trabalho relata o método de especiação de mercúrio em AP usando o sistema CV-AAS. Sob condições ajustadas de concentrações de sal e óleo (por diluição e centrifugação), uma alíquota de amostra foi tratada com SnCl2, levando ao Hg0 quantificado como mercúrio inorgânico original. Uma segunda alíquota de amostra foi exposta a UV (sob condições otimizadas) que promoveu a oxidação de CH3Hg a Hg2+, formando Hg2+ que foi posteriormente reduzido, com SnCl2, produzindo o Hg0 referente ao teor total de mercúrio na amostra. O teor de CH3Hg foi obtido pela diferença nos resultados alcançados para as duas alíquotas. O efeito matriz imposto por óleo e sal foram estudados e, apesar de afetar a intensidade do perfil do tempo de mercúrio, a quantificação foi alcançada com sucesso com padrões ajustados (assemelhamento de matriz) combinando quantidades de NaCl e óleo mineral. As medições de condutividade (estimativa de teor de sal) e turbidimétrica (estimativa de teor de óleo) foram feitas para as amostras de PW, a fim de permitir o ajuste adequado da amostra aos padrões correspondentes (contendo óleo mineral a 5 mg L-1 e NaCl a 5 g L-1). O método de adição de analito também foi utilizada e o limite de quantificação foi de 12 ng L-1. / [en] The aim of the present work was to develop analytical methods capable of determining mercury species such as methylmercury (CH3Hg), ethylmercury (CH3CH2Hg), inorganic mercury (Hg2+, Hg0), in produced water (PW) and urine, as well as thiomersal C9H9HgNaO2S) in effluent from a pharmaceutical industry and in urine. Despite many methods for quantifying mercury species are reported, few studies address speciation in PW, sample known to have high oil and salt contents. Besides, the use of nanomaterials such as graphene quantum dots (GQDs) alone or decorating titanium dioxide nanoparticles (GQDs-TiO2 NPs) were used as photocatalytic agents to produce the detected elemental mercury. The analytical techniques used for total mercury detection and mercury speciation were multipath cold vapor atomic absorption spectrometry (multipath˗CV˗AAS) and gas chromatography cold vapor atomic fluorescence spectrometry (GC˗CV˗AFS). In the first work, the photo-degradation of thiomersal has been achieved using visible light and GQDs, obtained from hydro-exfoliation of citric acid and glutathione, as catalysts. The generated Hg0 (using adjusted experimental conditions) was detected by multipath-CV-AAS, enabling quantification of thiomersal at values as low as 20 ng L-1 even in complex samples as aqueous effluents from the pharmaceutical industry and in the urine. The reaction kinetic (pseudo-first-order with k = 0.11 min-1 ) was determined. The second work provided a speciation method for mercury in PW using multipath-CV-AAS. Under adjusted salt and oil contents (by dilution and centrifuging), a sample aliquot was treated with SnCl2, leading to the Hg0 quantified as the original inorganic mercury. A second sample aliquot was exposed to UV (under optimized conditions) that promoted oxidation of CH3Hg to Hg2+, which was then reduced, with SnCl2, producing the Hg0 relative to the total mercury content in the sample. The CH3Hg content was obtained by the difference in results achieved for both aliquots. Matrix effects imposed by oil and salt were studied, and although affecting the intensity of the mercury time profile, quantification was successfully achieved by matrix-matched standards containing NaCl and mineral oil.

Call number: LD2668 .T4 1985 S337 / Master of Science