Proper management of soil organic matter (SOM) contributes to increasing plant productivity and reducing dependency on mineral fertilizers. Organic matter is widely regarded as a vital component of a healthy soil as it plays an important role in soil physical, chemical and biological fertility. Plant residues are the primary source of SOM. Therefore, proper SOM management requires a better understanding of plant residue decomposition kinetics in order to synchronize nutrient release during decomposition and plant uptake and prevent nutrient losses. In natural and managed ecosystems, residues are added frequently to soil, in the form of dead roots and litter fall of plant species with different C/N ratios. However, in most studies on residue decomposition, residues with different C/N ratios are added once and the effect of the presence of plants on residue decomposition is rarely investigated. In this project, four experiments were carried out with different objectives in order to close these knowledge gaps. The aim of the first experiment was to investigate the effect of frequent wheat residue addition on C mineralization and N dynamics. The experiment consisted of five treatments with different frequency of residue addition (2% w/w of wheat residues in total): once (100%W), every 16 days (25%), every 8 days (12.5%) or every 4 days (6.25%) and noresidue addition (control) with four replicates. The results showed that increasing frequency of low-N wheat residue addition increased C mineralization. Compared to 100%W, cumulative respiration per g residue at the end of the incubation (day 80) was increased by 57, 82 and 92% at 25%W, 12.5%W and 6.25%W, respectively. Despite large increases in cumulative respiration, frequent residue addition did not affect inorganic N or available N concentrations, microbial biomass C and N or soil pH. It is concluded that experiments with single residue additions may underestimate residue decomposition rates in the field because with several additions, soil microbes respire more of the added C (and possibly native soil C) per unit biomass but that this does not change their N requirements or the microbial community composition. In the second experiment, the effect of mixing of high and low C/N residues at different times during incubation was investigated. There were 4 addition times; 25% of a total of 2% (w/w) residue was added either as wheat (high C/N) or lupin (low C/N) residue. Wheat residue was added to lupin residues on days 16 (LW-16), 32 (LW-32) or 48 (LW-48). Additional treatments were 100%L (added 25% of lupin residues on days 0, 16, 32 and 48) and 100%W (added 25% of wheat residues on days 0, 16, 32 and 48) and 0% (the control) with four replicates. Adding high C/N residues into decomposing low C/N ratio residue strongly decreased the respiration rate compared to the addition of low C/N residues, and lowered the availability of inorganic N, but significantly increased soil pH and altered microbial community composition. By the end of the incubation on day 64, the cumulative respiration of LW-16, LW-32 and LW-48 was similar and approximately 30% lower than in the treatment with only lupin residue addition. The third experiment studied the effect of spatial separation of high and low C/N residues on decomposition and N mineralization. Each microcosm consisted of two PVC caps of 70 mm diameter and 20 mm height with the open end facing each other separated by a 30μm mesh. The caps were filled with soil mixed with either low or high C/N residue with three replicates. Contact of high and low C/N residues led to an increase in the decomposition rate of the high C/N residues at the interface whereas it decreased it in the low C/N residues. The results showed that N and soluble C compounds moved from the easily decomposable residues into the surrounding soil, thereby enhancing microbial activity, increasing inorganic N and significantly changing soil pH in the layer 0-5 mm from the interface compared to the 5-10 mm layer of the high C/N residues, whereas the movement of soluble C and N to high C/N residues decreased the decomposition of the low C/N residues. The final experiment investigated the effect of living plants on decomposition of high and low C/N residues. Wheat was grown in pots with a 30 μm mesh at the bottom. After a root mat had formed (>50% root coverage), a PVC cap with soil with high and low C/N residues (2% w/w) was placed against the mesh. The presence of plant roots significantly increased the respiration rate, N immobilization and increased the soil pH in the 0-5 mm layer in the first 4 days compared to the 5-10 mm layer. This enhanced microbial activity (and probably microbial biomass) can be explained by root exudates. The microbial community composition of plant treatments differed significantly from treatments without plants and the effect was greater in the immediate vicinity of the roots. / Thesis (M.Ag.Sc.) -- University of Adelaide, School of Earth and Environmental Sciences, 2009

Thesis (M.S.)--Indiana University, 2008. / Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Pierre-Andre Jacinthe, Lenore P. Tedesco, Philippe G. Vidon. Includes vita. Includes bibliographical references (leaves 95-99).

Made available in DSpace on 2014-06-11T19:23:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-30Bitstream added on 2014-06-13T19:09:19Z : No. of bitstreams: 1 peron_ab_me_bauru.pdf: 1180628 bytes, checksum: fdf98821f4364d3799335a94a181838b (MD5) / As indústrias de processamento de couros, conhecidas como curtumes ou indústrias de acabamento de couro apresentam grandes problemas ambientais. A preocupação com o meio ambiente por parte dos órgãos de controle ambiental fez com que muitas indústrias implantassem sistemas de tratamentos e destinação final dos resíduos gerados por elas. Associados à necessidade de materiais compostos, impulsionada pela crescente necessidade de novas tecnologias, principalmente a que se refere às combinações entre materiais, há alternativa de incorporação do resíduo em materiais já utilizados. Entre as alternativas tem-se a incorporação do resíduo em matrizes de cimento. Neste trabalho, pretende-se encapsular o lodo residual como alternativa de co-disposição do resíduo, em matrizes de cimento, utilizando cimento CPIIIF-32, em substituição parcial do agregado miúdo. O material foi coletado em um curtume na região centro-oeste do estado de São Paulo e caractrização de todos os insumos de concreto. Para os estudos utilizou-se um corpo-de prova referência e diferentes traços de concreto com adições de lodo residual seco a uma temperatura de 150ºC, com variação de 2% a 8% de resíduo em relação a areia utilizada no traço referência. Realizou-se ensaios de resistência mecânica, lixiviação e solubilização. Após a análise dos resultados, constatou-se que o resíduo pode ser considerado um plastificante na trabalhabilidade do concreto, atendendo aos limites de lixiviação e solubilização estipulados pelas normas 10005/2004 e 10006/2004. / The industries of leathers processin, konown as tanneries or industries of leather's finish, present great environmental problems. The concern with environment on the part of the agencies of environmental control made with that a lot of industries implanted systems of treatments and final destination of the residues generated by them. Associates to the necessary of composed materials stimulated by the increasing necessity of new technologies, mainly the one thet if it relates to the combinations between materials, there are the residue incorporation in the used material. Between the alternatives we have the incorporation of the residue in cement head offices. In this work, it intends encapsulate the residual silt as alternative of codisposition of the residue in cement head offices, using cements CPIIIF-32 in partial substitution of the small aggregate. The material was collected in a tannery in the area centerwest of the state of São Paulo and characterization of all the inputs of the concrete. For the studies a test body it was used reference and traces of concret with additions of dry residual silt in a temperature of 150ºC, with variation of 2% to 8% of residue in relation to sand used in the trace reference. One the became fullfilled rehearsals of mechanical resistance, leaching and solubilization. After results of the analysis, it was verified that the residue com be considered plastificate in the management of the concrete, taking care of to the leaching and solubilization limits stipulated by norms 10005/2004 and 10006/2004.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-03-12T16:05:55Z No. of bitstreams: 1 GUILHERME COSTA DE OLIVEIRA - TESE PPGEQ 2016.pdf: 2637788 bytes, checksum: 666ee4637bd3109b74c369b5faba3164 (MD5) / Made available in DSpace on 2018-03-12T16:05:55Z (GMT). No. of bitstreams: 1 GUILHERME COSTA DE OLIVEIRA - TESE PPGEQ 2016.pdf: 2637788 bytes, checksum: 666ee4637bd3109b74c369b5faba3164 (MD5) Previous issue date: 2016-08-31 / Capes / Dentre os diversos minerais extraídos, no Brasil, o caulim é um dos principais. Esse mineral de da família das caulinitas, apresenta uma grande versatilidade quanto ao seu uso. Porém, durante o processo de beneficiamento, altas quantidades do material extraído são rejeitadas, chegando a 70% do montante. Esse resíduo é disposto a céu aberto, causando transtorno às populações circunvizinhas e ao ecossistema da região. Esse trabalho objetivou utilizar o resíduo gerado nesse processo como matéria prima para o desenvolvimento de argamassas. O resíduo foi caracterizado, e utilizando a difratometria de raios X (DRX) verificou-se que é, basicamente, constituído de caulinita e mica. O resíduo foi testado quanto à sua pozolanicidade e verificouse que não apresentava potencial adequado para ser utilizado como substituinte parcial do cimento. Entretanto, suas características físicas indicaram que o resíduo de caulim apresentava propriedades para ser utilizado como agregado miúdo. Traços de argamassas colantes foram realizados substituindo o agregado miúdo natural, areia, pelo resíduo do caulim em proporções de 0 a 100 %. Essas argamassas foram testadas de acordo com as especificações contidas na norma ABNT NBR 14081. Os resultados indicaram que, à medida que se aumentou a quantidade de resíduo, a argamassa necessitou de uma maior quantidade de água para se obter a trabalhabilidade adequada. Com relação aos dados de resistências mecânicas, verificou-se um decaimento linear nos dados. Para o Tempo em Aberto (TA), observou-se uma redução de, aproximadamente, 90% na resistência mecânica do material; com relação às Resistências de Aderência à Tração (RAT), houve diminuição de 87% nas resistências mecânicas dos traços curados ao ar e, 81 %, nas argamassas curadas em meio aquoso. O traço que continha 25 % de seu agregado natural substituído por resíduo de caulim, apresentou valores dentro dos limites estabelecidos pela NBR 14081 e uma demanda de água próxima à das argamassas colantes industrializadas disponíveis no mercado. Dessa forma, o resíduo oriundo do processo de beneficiamento de caulim, apresentou-se como uma opção viável para a redução do uso de areia no desenvolvimento de argamassas colantes. Essa substituição foi favorável tanto para dar uma destinação ao resíduo, como também para a diminuição do uso de areia como agregado miúdo, uma vez que sua extração acarreta em diversos problemas ambientais. / Among various minerals extracted in Brazil, kaolin is one of most important. This mineral from the kaolinite family has great versatility as its use and during its beneficiation process, high amounts of the extracted material are rejected, reaching values as 70%. This residue is disposed on the environment with no treatment, causing inconvenience to surrounding communities and to the region ecosystem. This work aimed to use this residue as raw material for the construction industry, more specifically in the development of AC-I type adhesive mortars. The residue was characterized and by X-ray diffraction verified that it is basically constituted of kaolinite and mica. Based on Brazilian standards, the residue was tested for its pozzolanic and it was found that showed no suitable potential for using as a partial replacement for cement. However, its physical characteristics indicate that the kaolin residue had properties to be used as fine aggregate. Traces of adhesive mortars were made by replacing the fine natural aggregate, sand, by kaolin residue in proportions from 0 up to 100 %. The results indicated that, as it increased the amount of residue, the mortar required a larger amount of water to obtain adequate workability. Due to mechanical resistance data, there was a linear decay in. For the Open Time (TA), there was a reduction of approximately 90% in the mechanical strength of the material; and about to Resistance Adhesion Tensile (RAT), a reduction of 87 % in the mechanical strength of the admixtures air-cured and 81 % in the mortar cured in an aqueous medium. The admixtures that contained 25 % of its fine aggregate replaced by kaolin residue, showed values within the limits established by the NBR 14081 and a water demand close by the demand in industrialized adhesive mortars. Thus, the residue derived from kaolin beneficiation process, proved to be a viable option for reducing the use of sand in the development of adhesive mortars. This substitution is in favour both to give a destination to residue, also to reduce the use of sand as fine aggregate, since its extraction brings several environmental problems in.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-12T21:09:02Z No. of bitstreams: 1 SUELLEN LISBOA DIAS BELTRÃO - TESE PPG-CEMat 2014..pdf: 5738943 bytes, checksum: 0bccb1785d07e57f9e0fe26f6e6d41cc (MD5) / Made available in DSpace on 2018-04-12T21:09:02Z (GMT). No. of bitstreams: 1 SUELLEN LISBOA DIAS BELTRÃO - TESE PPG-CEMat 2014..pdf: 5738943 bytes, checksum: 0bccb1785d07e57f9e0fe26f6e6d41cc (MD5) Previous issue date: 2014-08-27 / CNPq / O ambiente construído do futuro está sendo edificado no começo de uma nova era ecológica, a da reutilização. Nesse sentido, a utilização de resíduos como forma alternativa de substituição do cimento em argamassas pode vir a alcançar o patamar da sustentabilidade. A produção excessiva de resíduos de caulim tanto no estado da Paraíba como no interior do estado do Rio Grande do Norte vem sendo alvo de pesquisas. Os resíduos de caulim oriundos do processo de beneficiamento do caulim classificados como resíduo grosso e resíduo fino são descartados de forma indiscriminada no meio ambiente, causando grande impacto ambiental e prejudicando a população circunvizinha das pilhas de resíduos. Na tentativa de propor alternativas para a reutilização destes resíduos e produção de materiais inovadores para os mais variados setores da construção civil este trabalho apresenta como objetivo avaliar o comportamento mecânico e durabilidade de argamassas incorporadas com resíduo de caulim calcinado. A mistura utilizada foi composta por 50% de resíduo de caulim grosso + 50% de resíduo de caulim fino, foram incorporados em argamassas nas proporções em massa de 1:2:6 e 1:2:8 com teores de substituição do cimento de 0%, 5%, 10%, 15%, 20% e 30%. mento de 0%, 5%, 10%, 15%, 20% e 30%. As argamassas foram submetidas a curas distintas sendo estas, realizadas em ambiente interno e em ambiente externo, obedecendo as idades de 30, 60, 90, 180 e 360 dias e ainda submetidas aos ensaios de durabilidade acelerada por meio dos ciclos de molhagem e secagem. Para a incorporação deste resíduo nas argamassas foram realizadas a caracterização física, química e mineralógica do resíduo, assim como avaliação da temperatura de queima do resíduo para avaliação da reatividade da pozolana. A pozolana com melhor característica física foi determinada a uma temperatura de 800°C e a partir desta, deu-se prosseguimento a incorporação do resíduo de caulim calcinado sob forma de pozolana nas argamassas. Foram moldados corpos de prova cilíndricos de 50 mm x 100 mm. Os corpos de prova conforme o tipo de cura e idade foram avaliados mecanicamente através do ensaio de resistência a compressão simples. Amostras das argamassas foram pulverizadas em pistilo com almofariz de porcelana e peneiradas em peneira ABNT de n°200 após o ensaio de resistência a compressão para serem analisadas por meio das técnicas de difratometria de raios-X, análise térmica diferencial e gravimétrica Diante dos valores de resistência apresentados, as argamassas com substituição do cimento pelo resíduo de caulim calcinado, podem ser classificadas de acordo com a NBR 13281 (2001) como sendo do Tipo I com valores de resistência mecânica ≥ 0,1 e ≤ 4,0 (MPa) e Tipo II com ≥ 4,0 e ≤ 8,0 (MPa) para ambos os traços 1:2:6 e 1:2:8. / The built environment of the future is being built at the beginning of a new was ecological, that of re-use. In this sense, the use of waste as alternative way of replacing the cement in mortars can reach the level of sustainability. Excessive production of waste from kaolin in the state of Paraíba and in the interior of the state of Rio Grande has been under investigation. The kaolin residues from the processing of kaolin classified as waste are disposed of indiscriminately in the environment, causing great environmental impact and damaging the surrounding population of waste batteries. In an attempt to propose alternatives for reuse of this waste and the production of innovative materials for the most varied sectors of construction, this paper presents the objective of evaluating the mechanical behavior and durability of mortars incorporated with residue of calcined kaolin. The mixture used was composed of 50% kaolin residue + 50% fine kaolin residue, were incorporated into the mortars in 1: 2: 6 and 1: 2: 8 mass proportions with cement substitution of 0%, 5%, 10%, 15%, 20% and 30%. 0%, 5%, 10%, 15%, 20% and 30%. The mortars were submitted to different cures, these being carried out in an environment internal and external environment, obeying the ages of 30, 60, 90, 180 and 360 days and subjected to the tests of accelerated durability by means of the wetting and drying cycles. For the incorporation of this residue in mortars were carried out the physical, chemical and mineralogical characterization of the residue, as well as the evaluation of the burning temperature of the residue for evaluation of pozzolan reactivity. Pozolana with better characteristics physics was determined at a temperature of 800 ° C and from this it was the incorporation of the residue of calcined kaolin in the form of pozzolan in mortars. 50 cylindrical specimens were molded mm x 100 mm. The specimens according to the type of cure and age were evaluated mechanically by the compressive strength test simple. Samples of the mortars were sprayed in pistil with porcelain mortar and sieved in No. 200 ABNT sieve after the test compression strength to be analyzed by X-ray diffraction, differential and gravimetric thermal analysis values ​​presented, mortars with by the residue of calcined kaolin, can be classified according to the with NBR 13281 (2001) as Type I with resistance values mechanics ≥ 0.1 and ≤ 4.0 (MPa) and Type II with ≥ 4.0 and ≤ 8.0 (MPa) for both traces 1: 2: 6 and 1: 2: 8.

Made available in DSpace on 2014-12-17T14:48:15Z (GMT). No. of bitstreams: 1 EmanuelHGP_DISSERT.pdf: 3584537 bytes, checksum: 4ba902ede1a2207775f10e4b471aa4a3 (MD5) Previous issue date: 2013-08-23 / From the 70`s, with the publication of the Manifesto for Environment UN Conference, held in Stockholm, in Sweden (1972), defend and improve the environment became part of our daily lives. Thus, several studies have emerged in several segments in order to reuse the waste. Some examples of waste incorporated in portland cement concrete are: rice husk ash, bagasse ash of cane sugar, powder-stone, microsilica, tire rubber, among others. This research used the residue of the mining industry Scheelite, to evaluate the incorporation of the residue composition of Portland cement concrete, replacing the natural sand. The percentage of residue were incorporated from 0% to 100%, with a variation of 10%, 11 being produced concrete mix in the ratio 1:2:3:0.60, by mass. We evaluated the following characteristics of concrete: slump test, compressive strength, tensile strength by diametral compression, water absorption, porosity and density, based on the ABNT, through tests performed in the Laboratory of Civil Construction, UFRN. The trace with the addition of 60% scheelite residue was obtained which better performance. Therefore, the use of the waste from the production of Scheelite is feasible due to the durability parameters (water absorption and porosity), sustainability, and the good results of the resistance of the concrete / A partir da d?cada de 70, com a publica??o do Manifesto Ambiental pela Confer?ncia das Na??es Unidas, realizada em Estocolmo, na Su?cia (1972), defender e melhorar o meio ambiente passou a fazer parte do nosso cotidiano. Dessa forma, v?rias pesquisas ligadas a sustentabilidade surgiram em diversos segmentos com o objetivo do aproveitamento de res?duos. Alguns exemplos de res?duos incorporados ao concreto de cimento Portland s?o: cinza da casca de arroz, cinza do baga?o de cana-de-a??car, p?-de-pedra, micros?lica, borracha de pneu, entre outros. Este estudo utilizou o res?duo da produ??o da ind?stria da minera??o de Scheelita, com o objetivo de avaliar a incorpora??o do res?duo ? composi??o do concreto de cimento Portland, em substitui??o da areia natural. As porcentagens incorporadas do res?duo foram de 0% at? 100%, com varia??o de 10%, sendo produzidos 11 tra?os de concreto na propor??o 1:2:3:0,60, em massa. Foram avaliadas as seguintes caracter?sticas do concreto: trabalhabilidade, resist?ncia ? compress?o axial, resist?ncia ? tra??o por compress?o diametral, absor??o de ?gua, ?ndice de vazios e massa espec?fica, tendo como base as normas da ABNT, atrav?s de ensaios realizados no Laborat?rio de Constru??o Civil da UFRN. O tra?o com a incorpora??o de 60% de res?duo de Scheelita foi o que obteve melhor desempenho. Portanto, o uso do res?duo da produ??o de Scheelita ? vi?vel, devido aos par?metros de durabilidade (absor??o de ?gua e ?ndice de vazios), da sustentabilidade, e dos bons resultados das resist?ncias do concreto

Made available in DSpace on 2014-12-17T14:48:16Z (GMT). No. of bitstreams: 1 FelipeMSC_DISSERT.pdf: 3412547 bytes, checksum: 6323164ff4e2d93c2b1596218608b86a (MD5) Previous issue date: 2014-01-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The use of sewage sludge as a raw material falls within the waste recycling key in the current process model environmental sustainability .Waste recycling has been consolidated as a sustainable environmentally sound technical solution, and. Despite showing very variable composition and characteristics, sewage sludge, can be considered as a residue with a high recycling potential in the building sector. In this paper the feasibility of using sewage sludge ash was studied in addition to Portland cement mortar in 1:3 mass considered the standard dash. This gray additions were studied in proportions of 5%, 10 %, 15 %, 20 %, 25% and 30% by mass of cement. The methodology was focused on the characterization of materials by physical, chemical , mechanical , environmental and morphological followed by the production of mortar tests ,and finalized by the characterization tests of mortar in the fresh state, through the consistency index, content of entrained air, bulk density and water retention, and in the hardened state by bulk density, water absorption by capillarity capillarity coefficient, compressive strength, tensile strength in bending ,tensile bond strength and microstructural analysis for percentages of 0 to 20%. After comparing with the standard mortar mortars with addition of ash, it is concluded that the ash of sewage sludge did not impair the integrity and properties of mortars with addition, including increasing resistance to compression and tension, being 20% more indicated percentage. Thus, it becomes feasible the addition of sewage sludge ash in Portland cement mortar for the trait studied / O uso de lodo de esgoto como mat?ria-prima se insere dentro do processo de reciclagem de res?duos, fundamental no modelo de sustentabilidade ambiental atual. A reciclagem de res?duos vem se consolidando como uma solu??o sustent?vel, t?cnica e ambientalmente correta. Apesar de apresentar composi??o e caracter?sticas muito vari?veis, o lodo de esgoto, pode ser considerado como um res?duo com alto potencial de reciclagem no setor da constru??o civil. Neste trabalho foi estudada a viabilidade de utiliza??o de cinza de lodo de esgoto como adi??o em argamassa de cimento Portland no tra?o 1:3 em massa considerado o tra?o padr?o. Foram estudadas adi??es desta cinza nas propor??es de 5%, 10%, 15%, 20%, 25% e 30% em rela??o ? massa de cimento. A metodologia foi centrada na caracteriza??o dos materiais por meio de ensaios f?sicos, qu?micas, mec?nicos, ambientais e morfol?gicos, seguida pela produ??o das argamassas, e finalizada pelos ensaios de caracteriza??o das argamassas no estado fresco, atrav?s do ?ndice de consist?ncia, teor de ar incorporado, densidade de massa e reten??o de ?gua, e no estado endurecido atrav?s da densidade de massa, absor??o de ?gua por capilaridade, coeficiente de capilaridade, resist?ncia ? compress?o, resist?ncia ? tra??o na flex?o, resist?ncia de ader?ncia ? tra??o e da an?lise microestrutural para as porcentagens de 0 e 20%. Ap?s comparar a argamassa padr?o com as argamassas com adi??o da cinza, conclui-se que a cinza de lodo de esgoto n?o prejudicou a integridade e propriedades das argamassas com adi??o, inclusive aumentando a resist?ncia ? compress?o e tra??o, sendo 20% a porcentagem mais indicada. Assim, torna-se vi?vel a adi??o de cinza de lodo de esgoto em argamassa de cimento Portland para o tra?o estudado

Doctor of Philosophy / Department of Statistics / Christopher Vahl / Veterinary drugs are used extensively for disease prevention and treatment in food producing animals. The residues of these drugs and their metabolites can pose risks for human health. Therefore, a withdrawal time is established to ensure consumer safety so that tissue, milk or eggs from treated animals cannot be harvested for human consumption until enough time has elapsed for the residue levels to decrease to safe concentrations. Part of the process to establish a withdrawal time involves a linear regression to model drug residue depletion over time. This regression model is used to calculate a one-sided, upper tolerance limit for the amount of drug residue remaining in target tissue as a function of time. The withdrawal period is then determined by finding the smallest time so that the upper tolerance limit falls below the maximum residue limit. Observations with measured residue levels at or below the limit of quantitation (LOQ) of the analytical method present a special challenge in the estimation of the tolerance limit. Because values observed below the LOQ are thought to be unreliable, they add in an additional source of uncertainty and, if dealt with improperly or ignored, can introduce bias in the estimation of the withdrawal time. The U.S. Food and Drug Administration (FDA) suggests excluding such data while the European Medicine Agency (EMA) recommends replacing observations below the LOQ with a fixed number, specifically half the value of the LOQ. However, observations below LOQ are technically left censored and these methods are do not effectively address this fact. As an alternative, a regression method accounting for left-censoring is proposed and implemented in order to adequately model residue depletion over time. Furthermore, a method based on generalized (or fiducial) inference is developed to compute a tolerance limit with results from the proposed regression method. A simulation study is then conducted to compare the proposed withdrawal time calculation procedure to the current FDA and EMA approaches. Finally, the proposed procedures are applied to real experimental data.

[pt] A indústria do petróleo tem suas atividades interpretadas como incompatíveis com o conceito de desenvolvimento sustentável. No entanto, o desenvolvimento da humanidade tem sido pautado no consumo de energia, grande parte fornecido por esta indústria. Atualmente face as recentes descobertas do pré sal, a nova fronteira exploratória no Brasil, é possível vislumbrar que o segmento de exploração se fará muito presente no país, assim como seus impactos negativos ao meio ambiente e suas toneladas de resíduo. A dissertação busca promover reflexão sobre o tema, tendo em vista análise de casos vivenciados pela indústria brasileira com a aplicação do conceito do ciclo de vida. A dissertação foi estruturada em capítulos que contextualizam tópicos necessários para um gerenciamento de resíduos eficiente tais quais o conceito de sustentabilidade e suas três dimensões, caracterização de resíduos, a precariedade da infraestrutura do país para destinação destes resíduos, assuntos regulatórios e a introdução ao conceito do ciclo de vida. A análise de alguns casos reais, com o base na teoria apresentada, corroborou para a conclusão de que a aplicação do conceito do ciclo de vida (CCV) ao gerenciamento dos resíduos traz o diferencial para redução a longo prazo desta poluição, por facilitar a análise de vários aspectos, desde a infraestrutura necessária para o gerenciamento como questões legais e de logística, nas fases de geração, armazenagem, transporte, tratamento e disposição final. O CCV ainda promove um melhor entendimento do público em geral, órgão regulamentadores, empresas operadores e prestadoras de serviços e permite que as empresas no Brasil, estejam melhor preparadas para os desafios relacionados à poluição advinda da geração destes resíduos. / [en] Oil and gas (OeG) activities continue to grow across the globe. Some people view the OeG industry as focused on profits with little concern for the environment, opposed to the concept of sustainability. However, demand for petroleum products continued to increase, and OeG continue to be the most widely used fuels. As energy demand continues to grow, petroleum companies must find and produce increasing quantities of OeG. But doing so, requires more than merely ramping up production from traditional sources. As nearby, relatively easy-to-produce resources diminish, new sources and locations are being developed in Brazil. The recent discovery in the pre-salt layer demonstrates the significant potential found, representing a new exploratory frontier in the country. OeG exploration today require the simultaneous consideration of a variety of economic, social, political, and environmental concerns. Historically, many foreign-operators started to invest in Brazil after the government opened the sector to competition. Increased drilling activity in Brazil both results in an increased amount of waste generated and sent onshore, air emission and water discharges. Once generated, managing these wastes in a manner that protects health and the environment will be essential for limiting operators legal and financial liabilities, therefore operators will have to manage the waste properly and consistent with all relevant laws and regulations in order to overcome the challenges of the increase of activities in this dynamic industry.

Este trabalho mostra os diversos sistemas de representação numérica, incluindo o sistema numérico normalmente utilizado em circuitos e alguns sistemas alternativos. Uma maior ênfase é dada ao sistema numérico por resíduos. Este último apresenta características muito interessantes para o desenvolvimento de circuitos aritméticos nos dias atuais, como por exemplo, a alta paralelização. São estudadas também as principais arquiteturas de somadores e multiplicadores. Várias descrições de circuitos aritméticos são feitas e sintetizadas. A arquitetura de circuitos aritméticos utilizando o sistema numérico por resíduos também é estudada e implementada. Os dados da síntese destes circuitos são comparados com os dados dos circuitos aritméticos tradicionais. Com isto, é possível avaliar as potenciais vantagens de se utilizar o sistema numérico por resíduos no desenvolvimento de circuitos aritméticos. / This work shows various numerical representation systems, including the system normally used in current circuits and some alternative systems. A great emphasis is given to the residue number system. This last one presents very interesting characteristics for the development of arithmetic circuits nowadays, as for example, the high parallelization. The main architectures of adders and multipliers are also studied. Some descriptions of arithmetic circuits are made and synthesized. The architecture of arithmetic circuits using the residue number system is also studied and implemented. The synthesis data of these circuits are compared with the traditional arithmetic circuits results. Then it is possible to evaluate the potential advantages of using the residue number system in arithmetic circuits development.