Substance use data such as alcohol drinking often contain a high proportion of zeros. In studies examining the alcohol consumption in college students, for instance, many students may not drink in the studied period, resulting in a number of zeros. Zero-inflated continuous data, also called semi continuous data, typically consist of a mixture of a degenerate distribution at the origin (zero) and a right-skewed, continuous distribution for the positive values. Ignoring the extreme non-normality in semi-continuous data may lead to substantially biased estimates and inference. Longitudinal or repeated measures of semi-continuous data present special challenges in statistical inference because of the correlation tangled in the repeated measures on the same subject. Linear mixed-eects models (LMM) with normality assumption that is routinely used to analyze correlated continuous outcomes are inapplicable for analyzing semi-continuous outcome. Data transformation such as log transformation is typically used to correct the non-normality in data. However, log-transformed data, after the addition of a small constant to handle zeros, may not successfully approximate the normal distribution due to the spike caused by the zeros in the original observations. In addition, the reasons that data transformation should be avoided include: (i) transforming usually provides reduced information on an underlying data generation mechanism; (ii) data transformation causes diculty in regard to interpretation of the transformed scale; and (iii) it may cause re-transformation bias. Two-part mixed-eects models with one component modeling the probability of being zero and one modeling the intensity of nonzero values have been developed over the last ten years to analyze the longitudinal semi-continuous data. However, log transformation is still needed for the right-skewed nonzero continuous values in the two-part modeling. In this research, we developed Bayesian hierarchical models in which the extreme non-normality in the longitudinal semi-continuous data caused by the spike at zero and right skewness was accommodated using skew-elliptical (SE) distribution and all of the inferences were carried out through Bayesian approach via Markov chain Monte Carlo (MCMC). The substance abuse/dependence data, including alcohol abuse/dependence symptoms (AADS) data and marijuana abuse/dependence symptoms (MADS) data from a longitudinal observational study, were used to illustrate the proposed models and methods. This dissertation explored three topics: First, we presented one-part LMM with skew-normal (SN) distribution under Bayesian framework and applied it to AADS data. The association between AADS and gene serotonin transporter polymorphism (5-HTTLPR) and baseline covariates was analyzed. The results from the proposed model were compared with those from LMMs with normal, Gamma and LN distributional assumptions. Simulation studies were conducted to evaluate the performance of the proposed models. We concluded that the LMM with SN distribution not only provides the best model t based on Deviance Information Criterion (DIC), but also offers more intuitive and convenient interpretation of results, because it models the original scale of response variable. Second, we proposed a flexible two-part mixed-effects model with skew distributions including skew-t (ST) and SN distributions for the right-skewed nonzero values in Part II of model under a Bayesian framework. The proposed model is illustrated with the longitudinal AADS data and the results from models with ST, SN and normal distributions were compared under different random-effects structures. Simulation studies are conducted to evaluate the performance of the proposed models. Third, multivariate (bivariate) correlated semi-continuous data are also commonly encountered in clinical research. For instance, the alcohol use and marijuana use may be observed in the same subject and there might be underlying common factors to cause the dependence of alcohol and marijuana uses. There is very limited literature on multivariate analysis of semi-continuous data. We proposed a Bayesian approach to analyze bivariate semi-continuous outcomes by jointly modeling a logistic mixed-effects model on zero-inflation in either response and a bivariate linear mixed-effects model (BLMM) on the positive values through a correlated random-effects structure. Multivariate skew distributions including ST and SN distributions were used to relax the normality assumption in BLMM. The proposed models were illustrated with an application to the longitudinal AADS and MADS data. A simulation study was conducted to evaluate the performance of the proposed models.

The scheduling of the converter aisle of a nickel smelting plant is a non-trivial task with significant consequences to plant profitability and production. An optimization-based scheduling formulation is developed using a continuous-time paradigm to accurately represent event timings. The formulation accounts for environmental restrictions on sulfur dioxide emissions using event timing constraints. The formulation includes novel semi-continuous modeling to represent flash furnaces which operate with a continuous inlet flow and intermittent discrete material removal, as well as, a novel sequencing and symmetry-breaking scheme to account for identical units operating in parallel. A rolling horizon feature is included in the formulation to accommodate multi-period optimization. Tightening constraints are developed and used to improve the computational performance of the optimization and demonstrate the capacity of the proposed methodology to function as a real-time decision-support tool. A solution procedure is presented where an aggregate model is used to bound the objective function of the master problem in a two layer optimization scheme. Finally, a novel multi-tiered procedure is presented to enhance the optimization solution by re-optimizing for objectives of decreasing priority in order to minimize task start times and penalize deviations in the furnace flow rate. To address the closed-loop properties of scheduling, a reactive scheduling mechanism is included to allow for rescheduling to account the impact of process disturbances on the operating schedule. A methodology for reducing radical scheduling changes due to the optimization during reactive scheduling is presented. The reactive scheduling algorithm utilizes a tiered optimization approach that progressively increases the degrees of freedom available, as required, in order to achieve a feasible production schedule. The use of the reactive scheduling algorithm demonstrates the ability to reject disturbances and transition plant operation in an agile manner. / Thesis / Master of Applied Science (MASc)

This study aimed at seeking for the solution to recover the energy from agriculture waste in the Mekong Delta, Vietnam. The spent mushroom compost - a residue from the mushroom growing - was chosen for co-digestion with pig manure in anaerobic batch and semi-continuous experiments. The results showed that in case of spent mushroom compost made up 75% of the mixed substrate, the gained biogas volume was not significantly different compared to the treatment fed solely with 100% pig manure. The average produced biogas was 4.1 L×day-1 in the experimental conditions. The semi-continuous experiments remained in good operation up to the 90th day of the fermentation without any special agitating method application. The methane contents in both experiments were around 60%, which was significantly suitable for energy purposes. These results confirm that spent mushroom compost is possibly an acceptable material for energy recovery in the anaerobic fermentation process. / Nghiên cứu này nhằm tìm kiếm giải pháp thu hồi năng lượng từ chất thải nông nghiệp tại ĐBSCL, Việt Nam. Rơm sau ủ nấm - phế phẩm sau khi trồng nấm rơm - được chọn để ủ kết hợp với phân heo trong các bộ ủ yếm khí theo mẻ và bán liên tục. Kết quả cho thấy nếu phối trộn đến 75% rơm sau ủ nấm trong nguyên liệu ủ, tổng lượng khí thu được không khác biệt đáng kể so với thí nghiệm ủ 100% phân heo. Trong điều kiện thí nghiệm, lượng khí thu được trung bình là 4.1 L.ngày-1. Thí nghiệm ủ bán liên tục vẫn vận hành tốt ở ngày thứ 90 mặc dù mẻ ủ không được khuấy đảo. Hàm lượng khí mê-tan đo được chiếm khoảng 60% hoàn toàn có thể sử dụng cho các nhu cầu về năng lượng. Những kết quả thí nghiệm khẳng định có thể sử dụng rơm sau ủ nấm để thu hồi năng lượng thông qua quá trình ủ yếm khí kết hợp.

Microalgas são organismos unicelulares, eucariontes, fotossintetizantes e eficientes fixadores de gás carbônico que apresentam grande potencial para produção de ácidos graxos além de pigmentos, como os carotenóides e a clorofila, de interesse nas indústrias de alimentos, química, farmacêutica e de cosméticos. Dentre as microalgas, o microrganismo Ankistrodesmus braunii vem sendo citado como capaz de produzir grandes quantidades de lipídios, podendo corresponder a até 73% de sua massa seca, com produção de ácidos graxos insaturados, como o ácido linolênico. Esse microrganismo se destaca do ponto de vista industrial por poder ser conduzido em reatores e em meios de cultivo complexos. As fontes de nitrogênio, as concentrações empregadas destes nutrientes, bem como o tipo de processo de cultivo interferem na composição de biomassas fotossintetizantes. O uso de reatores tubulares tem sido estudado e tem se apresentado interessante por permitir a obtenção de altas concentrações celulares. Nesse sentido, este trabalho teve a finalidade de estudar o crescimento de Ankistrodesmus braunii em reator tubular com uso de diferentes quantidades de nitrato de sódio por processos descontínuo, descontínuo alimentado e semi-contínuo. Nos cultivos descontínuos, a máxima concentração celular (Xm) encontrada foi de 1588 ± 11 mg.L-1 com uso de 20 mM de NaNO3. O uso do processo descontínuo alimentado, o qual teve adição de 20 mM de NaNO3 feito num intervalo a cada 48 horas sendo iniciada a adição no primeiro dia, permitiu a obtenção de Xm = 2753 ± 7 mg.L-1; porém não foi possível eliminar a fase lag do cultivo, levando a uma produtividade em células (Px) de 351 ± 1 mg.L-1.dia-1. O processo semi-contínuo foi eficiente para eliminar a fase lag do cultivo, permitindo a obtenção de Xm = 2399 ± 5 mg.L-1 e um aumento de até 50% em Px, que chegou a valores de 525 ± 1 mg.L-1.dia-1 em cultivos com uso de 20 mM de NaNO3. Nesta condição os teores de proteínas e lipídios nas biomassas foram de 34,8 ± 0,2% e 38,6 ± 0,2%, respectivamente. Foi observado que, independentemente do tipo de processo empregado, há um decréscimo do valor do fator de conversão de nitrogênio em células (YX/N) com o aumento da adição de NaNO3. O maior valor de YX/N foi obtido no experimento com processo semi-contínuo e uso de 2 mM de NaNO3 no meio de cultivo, com valor médio de 29,1 ± 0,1 mg mg-1 ao final do segundo ciclo. Porém, nesta condição, o teor de proteínas da biomassa foi de 17,3 ± 0,4%. Já os maiores valores de YX/N encontrados nos processos descontínuo e descontínuo alimentado foram, respectivamente, de 22,5 ± 1,6 e 7,1 ± 0,1 mg mg-1. Os resultados obtidos neste trabalho evidenciam o potencial de Ankistrodesmus braunii como fonte de proteínas e lipídios para uso industrial. / Microalgae are unicellular organisms, photosynthetic eukaryotes and which have great potential for the production of fatty acids as well as pigments such as carotenoids and chlorophyll, of interest in the food industry, chemicals, pharmaceuticals and cosmetics. Among the microalgae, the microorganism Ankistrodemsus braunii has been cited as capable of producing large amounts of lipids, which may correspond to up to 73% of its dry mass, producing unsaturated fatty acids, such as linolenic acid. This microorganism stands out from the industrial point of view because it can be carried out in reactors and in complex culture media. Nitrogen sources and concentrations employed of these nutrients interfere the composition of photosynthetic biomass and type of process employed also clearly exerts its influence both the growth and the composition of the biomass obtained. The use of tubular reactors has been studied and shown to be interesting because it allows the achievement of high cell concentrations. In this sense, this work aims to study the growth of Ankistrodemsus braunii tubular reactor using different amounts of nitrogen and under different forms of cultivation. In batch cultures, the maximum cell concentration (Xm) was found to be 1588 ± 11 mg.L-1, using 20 mM NaNO3. The use of the fed batch process, which had the addition of 20 mM NaNO3 in a range of 48 to 48 hours from the first to the sixth day, afforded Xm = 2753 ± 7 mg.L-1;ever it was not possible to eliminate the lag phase cultivation, leading to a productivity of cells (Px) of 351 ± 1 mg.L-1.day-1. The semi-continuous process was effective to eliminate the lag phase of the culture, allowing to obtain Xm = 2399 ± 5 mg.L-1 and increased up to 50% the Px value, which reached values of 525 ± 1 mg.L-1.day-1 in cultures with the use of 20 mM of NaNO3. In this condition the protein levels and lipid in the biomass were 34,8 ± 0,2% and 38,6 ± 0,2%, respectively. In all culture processes, it was observed that regardless of the type of process used, there is a decrease in the amount of nitrogen conversion factor into cells (YX/N) with increasing addition of NaNO3. The highest value of YX/N was obtained in the experiment with semi-continuous process with the use of 2 mM of NaNO3 in the culture medium, with an average of 29.1 ± 0.1 mg mg-1 at the end of the second cycle. However, in this condition, the protein content of the biomass was 17.3 ± 0.4%. The best values of YX/N found in the batch and fed-batch processes were, respectively, 22.5 ± 1.6 and 7.1 ± 0.1 mg mg-1. The results of this study shows the potential of Ankistrodemsus braunii as a source of protein and lipids for industrial use.

Microalgas são organismos unicelulares, eucariontes, fotossintetizantes e eficientes fixadores de gás carbônico que apresentam grande potencial para produção de ácidos graxos além de pigmentos, como os carotenóides e a clorofila, de interesse nas indústrias de alimentos, química, farmacêutica e de cosméticos. Dentre as microalgas, o microrganismo Ankistrodesmus braunii vem sendo citado como capaz de produzir grandes quantidades de lipídios, podendo corresponder a até 73% de sua massa seca, com produção de ácidos graxos insaturados, como o ácido linolênico. Esse microrganismo se destaca do ponto de vista industrial por poder ser conduzido em reatores e em meios de cultivo complexos. As fontes de nitrogênio, as concentrações empregadas destes nutrientes, bem como o tipo de processo de cultivo interferem na composição de biomassas fotossintetizantes. O uso de reatores tubulares tem sido estudado e tem se apresentado interessante por permitir a obtenção de altas concentrações celulares. Nesse sentido, este trabalho teve a finalidade de estudar o crescimento de Ankistrodesmus braunii em reator tubular com uso de diferentes quantidades de nitrato de sódio por processos descontínuo, descontínuo alimentado e semi-contínuo. Nos cultivos descontínuos, a máxima concentração celular (Xm) encontrada foi de 1588 ± 11 mg.L-1 com uso de 20 mM de NaNO3. O uso do processo descontínuo alimentado, o qual teve adição de 20 mM de NaNO3 feito num intervalo a cada 48 horas sendo iniciada a adição no primeiro dia, permitiu a obtenção de Xm = 2753 ± 7 mg.L-1; porém não foi possível eliminar a fase lag do cultivo, levando a uma produtividade em células (Px) de 351 ± 1 mg.L-1.dia-1. O processo semi-contínuo foi eficiente para eliminar a fase lag do cultivo, permitindo a obtenção de Xm = 2399 ± 5 mg.L-1 e um aumento de até 50% em Px, que chegou a valores de 525 ± 1 mg.L-1.dia-1 em cultivos com uso de 20 mM de NaNO3. Nesta condição os teores de proteínas e lipídios nas biomassas foram de 34,8 ± 0,2% e 38,6 ± 0,2%, respectivamente. Foi observado que, independentemente do tipo de processo empregado, há um decréscimo do valor do fator de conversão de nitrogênio em células (YX/N) com o aumento da adição de NaNO3. O maior valor de YX/N foi obtido no experimento com processo semi-contínuo e uso de 2 mM de NaNO3 no meio de cultivo, com valor médio de 29,1 ± 0,1 mg mg-1 ao final do segundo ciclo. Porém, nesta condição, o teor de proteínas da biomassa foi de 17,3 ± 0,4%. Já os maiores valores de YX/N encontrados nos processos descontínuo e descontínuo alimentado foram, respectivamente, de 22,5 ± 1,6 e 7,1 ± 0,1 mg mg-1. Os resultados obtidos neste trabalho evidenciam o potencial de Ankistrodesmus braunii como fonte de proteínas e lipídios para uso industrial. / Microalgae are unicellular organisms, photosynthetic eukaryotes and which have great potential for the production of fatty acids as well as pigments such as carotenoids and chlorophyll, of interest in the food industry, chemicals, pharmaceuticals and cosmetics. Among the microalgae, the microorganism Ankistrodemsus braunii has been cited as capable of producing large amounts of lipids, which may correspond to up to 73% of its dry mass, producing unsaturated fatty acids, such as linolenic acid. This microorganism stands out from the industrial point of view because it can be carried out in reactors and in complex culture media. Nitrogen sources and concentrations employed of these nutrients interfere the composition of photosynthetic biomass and type of process employed also clearly exerts its influence both the growth and the composition of the biomass obtained. The use of tubular reactors has been studied and shown to be interesting because it allows the achievement of high cell concentrations. In this sense, this work aims to study the growth of Ankistrodemsus braunii tubular reactor using different amounts of nitrogen and under different forms of cultivation. In batch cultures, the maximum cell concentration (Xm) was found to be 1588 ± 11 mg.L-1, using 20 mM NaNO3. The use of the fed batch process, which had the addition of 20 mM NaNO3 in a range of 48 to 48 hours from the first to the sixth day, afforded Xm = 2753 ± 7 mg.L-1;ever it was not possible to eliminate the lag phase cultivation, leading to a productivity of cells (Px) of 351 ± 1 mg.L-1.day-1. The semi-continuous process was effective to eliminate the lag phase of the culture, allowing to obtain Xm = 2399 ± 5 mg.L-1 and increased up to 50% the Px value, which reached values of 525 ± 1 mg.L-1.day-1 in cultures with the use of 20 mM of NaNO3. In this condition the protein levels and lipid in the biomass were 34,8 ± 0,2% and 38,6 ± 0,2%, respectively. In all culture processes, it was observed that regardless of the type of process used, there is a decrease in the amount of nitrogen conversion factor into cells (YX/N) with increasing addition of NaNO3. The highest value of YX/N was obtained in the experiment with semi-continuous process with the use of 2 mM of NaNO3 in the culture medium, with an average of 29.1 ± 0.1 mg mg-1 at the end of the second cycle. However, in this condition, the protein content of the biomass was 17.3 ± 0.4%. The best values of YX/N found in the batch and fed-batch processes were, respectively, 22.5 ± 1.6 and 7.1 ± 0.1 mg mg-1. The results of this study shows the potential of Ankistrodemsus braunii as a source of protein and lipids for industrial use.

A produção de H2S (sulfeto de hidrogênio) é um dos principais problemas na indústria do petróleo, sendo esta uma das causas da corrosão de tanques de estocagem e tubulações. Essa produção é possibilitada devido à injeção de água do mar durante o processo de recuperação secundária do petróleo, onde alguns micro-organismos presentes nessa água, tais como as bactérias anaeróbias heterotróficas totais (BANHT) e as bactérias redutoras de sulfato (BRS), que promovem a redução do sulfato a sulfeto. Atualmente, o método de quantificação destes micro-organismos é a técnica do Número Mais Provável (NMP) que estima o resultado em aproximadamente 28 dias. No presente trabalho foi utilizada a metodologia da produção semi-contínua de sulfeto biogênico pelo período de 15 dias, com o intuito de correlacionar com os resultados das quantificações de BANHT e BRS através da técnica convencional do NMP. Foram analisadas amostras de diferentes procedências da indústria do petróleo, apresentando variação na salinidade de 0 a 16 g.L-1. O objetivo deste procedimento foi avaliar as velocidades específicas e instantâneas de produção de H2S, sugerindo, desta forma, quais amostras apresentam maior potencial para a produção biogênica de sulfeto e em quais condições essa produção se dá. Observou-se que em todas as amostras a geração do H2S se dá de forma crescente até a estabilização desta produção, sendo esta obtida quase sempre em seis dias (144h) do crescimento microbiano. A produção do sulfeto biogênico se deu de forma mais intensa nas amostras do fundo de tanque de estocagem de óleo e da água de formação. A quantificação das BANHT e das BRS foram avaliadas pelo método do NMP de acordo com a tabela de Harrigan, a qual subestima a população microbiana, desconsiderando erros provenientes da técnica / The production of H2S (hydrogen sulfide) is a major problem in the oil industry, which is a cause of corrosion of pipes and storage tanks. This production is made possible due to seawater injection during the secondary oil recovery process where some microorganisms present in this water, such as total heterotrophic anaerobic bacteria (THAB) and sulphate-reducing bacteria (SRB) that promote reduction of sulfate to sulfide. Currently, the method of quantification of these microorganisms is the technique of the Most Probable Number (MPN) which estimates the results in about 28 days. The present study used the methodology of semi-continuous production of biogenic sulfide by 15 days period, in order to correlate with the measurements results of BANHT and BRS through the conventional technique of MPN. There were several samples analyzed from different origins in the oil industry, with variations in salinity from 0 to 16 g.L-1. The purpose of this procedure was to evaluate the specific speeds and instantaneous H2S production, suggesting thereby that samples had increased biogenic sulfide production and this production conditions which occurs. It was observed that all samples in the generation of H2S occurs incrementally until stabilization of this production, these being almost always obtained in six days (144h) of microbial growth. The production of biogenic sulfide occurred more intensely in the samples of oil storage tank bottom and formation water. The quantification of SRB and THAB were evaluated by the MPN method according to Harrigan table, which underestimates the microbial population, disregarding errors arising in the art

A produção de H2S (sulfeto de hidrogênio) é um dos principais problemas na indústria do petróleo, sendo esta uma das causas da corrosão de tanques de estocagem e tubulações. Essa produção é possibilitada devido à injeção de água do mar durante o processo de recuperação secundária do petróleo, onde alguns micro-organismos presentes nessa água, tais como as bactérias anaeróbias heterotróficas totais (BANHT) e as bactérias redutoras de sulfato (BRS), que promovem a redução do sulfato a sulfeto. Atualmente, o método de quantificação destes micro-organismos é a técnica do Número Mais Provável (NMP) que estima o resultado em aproximadamente 28 dias. No presente trabalho foi utilizada a metodologia da produção semi-contínua de sulfeto biogênico pelo período de 15 dias, com o intuito de correlacionar com os resultados das quantificações de BANHT e BRS através da técnica convencional do NMP. Foram analisadas amostras de diferentes procedências da indústria do petróleo, apresentando variação na salinidade de 0 a 16 g.L-1. O objetivo deste procedimento foi avaliar as velocidades específicas e instantâneas de produção de H2S, sugerindo, desta forma, quais amostras apresentam maior potencial para a produção biogênica de sulfeto e em quais condições essa produção se dá. Observou-se que em todas as amostras a geração do H2S se dá de forma crescente até a estabilização desta produção, sendo esta obtida quase sempre em seis dias (144h) do crescimento microbiano. A produção do sulfeto biogênico se deu de forma mais intensa nas amostras do fundo de tanque de estocagem de óleo e da água de formação. A quantificação das BANHT e das BRS foram avaliadas pelo método do NMP de acordo com a tabela de Harrigan, a qual subestima a população microbiana, desconsiderando erros provenientes da técnica / The production of H2S (hydrogen sulfide) is a major problem in the oil industry, which is a cause of corrosion of pipes and storage tanks. This production is made possible due to seawater injection during the secondary oil recovery process where some microorganisms present in this water, such as total heterotrophic anaerobic bacteria (THAB) and sulphate-reducing bacteria (SRB) that promote reduction of sulfate to sulfide. Currently, the method of quantification of these microorganisms is the technique of the Most Probable Number (MPN) which estimates the results in about 28 days. The present study used the methodology of semi-continuous production of biogenic sulfide by 15 days period, in order to correlate with the measurements results of BANHT and BRS through the conventional technique of MPN. There were several samples analyzed from different origins in the oil industry, with variations in salinity from 0 to 16 g.L-1. The purpose of this procedure was to evaluate the specific speeds and instantaneous H2S production, suggesting thereby that samples had increased biogenic sulfide production and this production conditions which occurs. It was observed that all samples in the generation of H2S occurs incrementally until stabilization of this production, these being almost always obtained in six days (144h) of microbial growth. The production of biogenic sulfide occurred more intensely in the samples of oil storage tank bottom and formation water. The quantification of SRB and THAB were evaluated by the MPN method according to Harrigan table, which underestimates the microbial population, disregarding errors arising in the art

Submitted by Neusa Fagundes (neusa.fagundes@unioeste.br) on 2017-09-15T19:02:10Z No. of bitstreams: 1 Simoni_Venzon2017.pdf: 2968978 bytes, checksum: 8d86880483b828aa9362b011294b38c9 (MD5) / Made available in DSpace on 2017-09-15T19:02:10Z (GMT). No. of bitstreams: 1 Simoni_Venzon2017.pdf: 2968978 bytes, checksum: 8d86880483b828aa9362b011294b38c9 (MD5) Previous issue date: 2017-02-17 / Along with the expansion of poultry activity, expressive amounts of poultry litter are generated every year, reaching 100 million tons. An alternative for the disposal of this residue is its use as a substrate for anaerobic biodigestion, which converts organic matter into biogas and digestate, with high nutritive value that can be used as biofertilizer. Because it is a solid residue with low humidity, to facilitate digestion, currently, large amounts of potable water are used. In this study, potable water was replaced by another liquid residue, swine wastewater, highlighting a co-digestion. Co-digestion of the poultry litter with the swine effluent was performed in a horizontal tubular anaerobic reactor with semi-continuous feed, operated at room temperature. By means of the application of a central rotational compound design, the biogas production was studied according to the operational parameters: volatile solids fed, in concentrations ranging from 2 to 8%, and hydraulic retention time, in intervals of 2.95 to 17.05 days. The effluent with low concentrations of nitrogen, total solids and alkalinity together with the reduced concentrations of Ca, K, Zn and absence of Cu can be used in co-digestion with the chicken litter, imparting humidity and neutralizing the toxicity of inhibitory compounds. Biogas production in all biodigesters started on the first day of operation and stabilized soon after the adaptation period (100 h), due to the good quality of the inoculum that had previously been acclimatized. The biogas production rate ranged from 73.69 to 295.26 dm3.kgSVal-1. An increase in biogas production rate can be achieved with high periods of hydraulic retention and with a lower concentration of volatile solids fed to the digester. The highest biogas production rate, with 48% methane, was obtained in a reactor fed with 2.87% volatile solids and hydraulic retention time of 15 days, yielding an energy potential of 0.034 MJ.day-1. The obtained statistical model was able to explain in 90% the experimental data and can be used in the prediction of the biogas production from co-digestion with poultry litter and swine wastewater. Even with the high alkalinity from the poultry litter, it was not enough to buffer the accumulation of volatile acids, occurring decrease in pH. In all reactors the carbon: nitrogen ratio in the substrates remained around 32.04±0.01 and there was no increase in pH, indicating no inhibition by ammonia. In all the reactors there was reduction of organic and nitrogen loads. Even with high organic load and in the presence of plant and soil nutrients, the digestates can be used as fertilizer with economic and ecological benefits. / Junto à expansão da atividade avícola, expressivas quantidades de cama de frango são geradas todo ano, podendo chegar a 100 milhões de toneladas. Uma alternativa para a disposição deste resíduo está na sua utilização como substrato para biodigestão anaeróbia, que converte a matéria orgânica em biogás e digestato, com alto valor nutritivo e que pode ser utilizado como biofertilizante. Por ser um resíduo sólido com pouca umidade, para favorecer a digestão, atualmente são utilizadas grandes quantidades de água, a qual foi aqui substituída por outro resíduo líquido: água residuária de abatedouro e indústria de beneficiamento de suínos, evidenciando uma codigestão. A codigestão da cama de frango com efluente suíno foi realizada em um reator anaeróbio tubular horizontal com alimentação semi-contínua, operado à temperatura ambiente. Por meio da aplicação de um DCCR, a produção de biogás foi estudada em função das condições operacionais: sólidos voláteis adicionados, em concentrações que variaram de 2 a 8%, e tempo de retenção hidráulica, em intervalos de 2,95 a 17,05 dias. O efluente com baixas concentrações de nitrogênio, sólidos totais e alcalinidade, junto com as reduzidas concentrações de Ca, K, Zn e ausência de Cu, pode ser utilizado em codigestão com a cama de frango, conferindo umidade e a neutralização da toxicidade de compostos inibitórios. A produção de biogás em todos os biodigestores começou ainda no primeiro dia de operação e estabilizou logo após o período de adaptação (100 h), devido à boa qualidade do inóculo, que havia sido previamente aclimatado. A taxa de produção de biogás variou de 73,69 a 295,26 dm3.kgSVal-1. Um aumento na taxa de produção de biogás pode ser conseguido com elevados tempos de retenção hidráulica e com uma menor concentração de sólidos voláteis adicionados ao biodigestor. A maior taxa de produção de biogás, com 48% de metano, foi obtida em um reator alimentado com 2,87% de sólidos voláteis e tempo de retenção hidráulica de 15 dias, rendendo um potencial energético de 0,034 MJ.dia-1. O modelo estatístico obtido conseguiu explicar em 90% os dados experimentais e pode ser utilizado na previsão da produção de biogás a partir da codigestão com cama de frango e água residuária de abatedouro e indústria de beneficiamento de suínos. Mesmo com a alta alcalinidade proveniente do resíduo cama de frango, esta não foi suficiente para tamponar o acúmulo de ácidos voláteis, ocorrendo a queda do pH. Em todos os reatores, a razão C:N nos substratos permaneceu em torno de 32,04±0,01 e não houve aumento do pH, indicando que não houve inibição por amônia. Em todos os reatores houve redução da carga orgânica e de nitrogênio. Ainda com alta carga orgânica e na presença de nutrientes das plantas e do solo, como S, Ca, Mg e pequenas quantidades de metais pesados, os digestatos podem ser utilizados como fertilizante com benefícios econômicos e ecológicos.

Traditionally, joints are assumed to be either pinned or fully rigid, but in reality, many behave between these two extremes giving them a semi-rigid classification. By acknowledging the semi-rigidity of nominal pin joints, steel frames can be designed as semi-continuous in which the beam bending moments are partially transmitted to the column members and the need for lateral bracing is eliminated, thus reducing material and construction costs. This thesis presents the results of numerical and theoretical studies of the behaviour of bolted endplate connections to Rectangular Hollow Section (RHS) columns using flowdrill bolts and their applications in semi-continuous frame design. Such connections exhibit significant levels of initial stiffness, strength, and deformation capacity while being more cost-effective than fully welded connections. Despite this, there is limited theoretical work carried out that allows such connections to be designed using analytical methods. In addition, there are no standardised connection design tables like that for open section columns (SCI, 1995), thereby inhibiting their adoption in practice. In this thesis, newly derived equations for initial stiffness that have a greatly improved range of validity and accuracy over existing equations are presented. Equations for bending strength of a newly derived elliptical mechanism based on yield line theory and for membrane action based on internal work principles are given. Equations for flowdrill thread stripping due to gross deformation of the RHS face are also presented thus allowing prediction of all common RHS face failure mechanisms. Equations for deformation capacity are derived thus making it possible to predict the full load-deflection behaviour of the RHS face in tension component. When combined with existing equations for bolt and endplate components, it is possible to predict the full moment-rotation behaviour of bolted endplate connections to RHS columns. Extensive parametric studies using finite element analysis (FEA) as well as validation against existing tests show that the newly derived equations can accurately predict the component-level and whole joint behaviour for a wide range of configurations. Taking advantage of the initial stiffness properties that these connections offer, a parametric study is conducted to show that connections with relatively simple detailing can offer sufficient initial stiffness and strength to enable unbraced semi-continuous design of low-rise steel frames. A hand calculation method for SLS sway in semi-continuous frames is also presented thus allowing the designer to readily carry out scheme designs without advanced software knowledge. A systematic method for the detailing of these connections for use in unbraced frame design is presented to facilitate adoption in practice.

The promulgation of revised standards for atmospheric fine particles (PM2.5) by the US EPA has sparked renewed interest in the ability to accurately measure and characterize suspended atmospheric particulate matter. Semi-volatile material (SVM), consisting of ammonium nitrate and semi-volatile organic material (SVOM), is not accurately measured by EPA accepted methods such as the Federal reference method (FRM) or Tapered Element Oscillating Microbalance (TEOM). However, SVM is often a major fraction of urban aerosols. Recent advances in atmospheric sampling instrumentation allowed for the semi-continuous characterization of urban PM2.5, including SVM. The Filter Dynamic Measurement System (FDMS) was shown to measure total PM2.5 mass including semi-volatile species. Validation of the FDMS was performed by comparison with the particle concentrator-Brigham Young University organic sampling system (PC-BOSS) and the real-time total ambient mass sampler (RAMS). Semi-continuous ambient particulate concentrations of sulfate, nitrate and ammonium ion were measured by a newly developed Dionex instrument which was field tested and validated for the first time in Fresno, CA. Either a modified Sunset Laboratory carbon monitor, collocated with a conventional Sunset carbon monitor employing a common inlet, or the newly developed dual-oven Sunset monitor allowed for the semi-continuous determination of both nonvolatile and semi-volatile organic material. This was the first attempt to characterize both nonvolatile and semi-volatile fractions of an urban aerosol in a semi-continuous manner using all semi-continuous instruments. A suite of instruments for semi-continuous PM2.5 monitoring was recommended including, an R&P FDMS for the measurement of PM2.5 mass, a dual-oven Sunset monitor for the measurement of nonvolatile and semi-volatile carbonaceous species, and a Dionex GP-IC for the measurement of inorganic species. A TEOM monitor is also recommended to measure nonvolatile PM2.5 mass. Using these instruments, semi-continuous mass closure was obtained for the first time during a study conducted in Riverside, CA. The advantage of using semi-continuous sampler data in the application of source apportionment was elucidated. Local aerosols are often impacted by short-term pollution episodes that cannot be temporally resolved using integrated samplers. One-h averaged data applied to source apportionment models was shown to increase the power of the model to predict sources, both primary and secondary, that exhibit diurnal short-term episodes.