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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

\"Avaliação dos resultados analíticos de hidrocarbonetos como instrumento jurídico em caso de derrames de petróleo: mangue de Bertioga\" / Evaluation of analytical results of hydrocarbons as judicial instrument in petroleum spills: Bertioga mangrove

Coimbra, Mauricio Antonio Covre 26 February 2007 (has links)
A avaliação da presença de hidrocarbonetos de petróleo em mangue na região entre a Estrada Rio-Santos e o Canal Bertioga ? São Paulo ? Brasil foi realizada através da análise de amostras de sedimento coletadas em testemunhos em épocas distintas (2001 e 2005). O rompimento de um oleoduto em outubro de 1983 derramou 3.000.000 litros de petróleo (também analisado) nesse local. Esse óleo desceu pelo Rio Iriri até atingir o Canal de Bertioga, espalhando-se por cerca de 60 quilômetros. Uma batalha jurídica teve início em 1985 e se encontra atualmente em fase de execução da sentença. Neste trabalho foram descritas algumas questões jurídicas envolvendo o derramamento ocorrido e as análises químicas para serem utilizadas como nexo causal. Os hidrocarbonetos foram analisados através da extração com solvente orgânico em sistema Soxhlet e por cromatografia a gás com detecção de ionização de chama (GC-FID) para n-alcanos e alcanos isoprenóides e com espectrometria de massas (GC-MS) para biomarcadores de petróleo e compostos policíclicos aromáticos (CPAs). Os resultados dos hidrocarbonetos alifáticos somente permitiram avaliar a contribuição de origem petrogênica pela presença de mistura complexa não resolvida (UCM) em algumas amostras de sedimentos. Não foi possível avaliar a contribuição petrogênica nos sedimentos baseado nas concentrações de n-alcanos, de alifáticos totais e as relações pristano/fitano, pristano/n-C17 e fitano/n-C18. A relação entre os homólogos e isômeros dos biomarcadores de petróleo, entretanto, indicou a presença do petróleo derramado no mangue depois de duas décadas. As maiores concentrações dos biomarcadores de petróleo foram encontradas na região mais próxima do derramamento e nos topos dos testemunhos. As análises de CPAs nos sedimentos foram importantes para a identificação de compostos mutagênicos e carcinogênicos provenientes do petróleo derramado no mangue. / The evaluation of the presence of hydrocarbons of oil in mangrove in the region between the Rio-Santos Road and Bertioga Channel - São Paulo - Brazil was carried out through the analysis of sediment samples collected in cores in distinct times (2001 and 2005). The disruption of a pipeline in October of 1983 spilled 3,000,000 of liters of petroleum (also analyzed) in that area. That oil has gone down the Iriri River as far as the Bertioga Channel and has spread for about 60 kilometers. A judicial process has been started in 1985 and nowadays it is in the final phase when the sentence will be given by the law court. In this work some legal issues involving the occurred spilling and the chemical analyses have been described to be used as causal nexus. The hydrocarbons have been analyzed through an organic solvent extraction using Soxhlet apparatus and gas chromatography with flame ionization detection (GC-FID) for n-alkanes and isoprenoids alkanes, and with mass spectrometer (GC-MS) for petroleum biomarkers and polycyclic aromatic compounds (PACs). The analysis of the aliphatic hydrocarbons allowed evaluating only the contribution of petrogenic origin through the presence of unresolved complex mixture (UCM) in some sediment samples. It has not been possible to evaluate the petrogenic contribution in the sediments based on the concentrations of n-alkanes, total aliphatic hydrocarbons and the ratios between pristane/n-C17 and phythane/n-C18. The ratio between petroleum biomarker homologous and isomers has indicated the presence of the oil spilled in the mangrove after two decades. The highest concentrations of the petroleum biomarkers have been found in the region next to the spilling and in the top-core samples. The analyses of CPAs in the sediments have been important to the identification of mutagenic and carcinogenic compounds present in the petroleum spilled in the mangrove.
32

Estimativa da ingestão e digestibilidade em bovinos de corte alimentados com Brachiaria brizantha cv. Marandu

Morais, Jucileia Aparecida da Silva [UNESP] 20 February 2008 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-02-20Bitstream added on 2014-06-13T21:05:24Z : No. of bitstreams: 1 morais_jas_dr_jabo.pdf: 409768 bytes, checksum: b454869362f63b6dd4c538254cae1c13 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O trabalho teve por objetivo estimar a ingestão de matéria seca (IMS) e a digestibilidade da matéria seca (DMS) em bovinos alimentados com Brachiaria brizantha cv. Marandu. Para isso, foram realizados 3 experimentos. O primeiro experimento foi conduzido com o objetivo de validar a metodologia dos n-alcanos para estimar a produção fecal, ingestão e digestibilidade em novilhos Nelore alimentados com capim Marandu em duas diferentes idades de rebrota. No segundo experimento, avaliaram-se os efeitos da redução da freqüência de suplementação no desempenho, IMS, DMS e tempo de pastejo de novilhos mantidos em pastagem de capim Marandu de fevereiro a maio de 2006 e onde foi oferecido um suplemento a base de glúten de milho na quantidade de 0,5% do peso corporal/dia. O terceiro experimento foi realizado para verificar as implicações da redução da freqüência de fornecimento da suplementação na fermentação ruminal de novilhos mantidos em pastagem com capim Marandu. Como principais resultados observou-se que o par de alcanos C32:C33 foi adequado para estimar a IMS e o alcano C35 para estimar a DMS. O mês do ano exerceu importante efeito na disponibilidade e composição bromatológica da forragem, na IMS, na DMS, na produção de ácidos graxos de cadeia curta... / The objectives of this work were to estimate the dry matter intake (DMI) and the dry matter digestibility (DMD) in beef cattle feeding Brachiaria brizantha cv. Marandu. For that, 3 experiments were accomplished. In the first experiment, the objective was to analyser the n-alkanes methodology to estimate the faecal production, intake and digestibility in Nelore steers feeding with Marandu grass in two different regrowth ages. In the second experiment, was evaluated the effect of the reduction of the supplementation frequency in the performance, DMI, DMD and grazing time of steers maintained in grazing of Marandu grass of February to May of 2006 and receiving a supplement the base of corn gluten in the amount of 0.5% of the body weight/day. The third experiment was accomplished to verify the implications of the decreasing the frequency of supplementation in the ruminal fermentation of steers maintained in Marandu pasture. Observed that the pair of alkanes C32:C33 was suitable to estimate DMI and the alkane C35 to estimate DMD. The month of the year cause important effect in the forage availability and the bromathologic composition, in the DMI, DMD and short-chain fatty acids production and, consequently, in the performance of bovine in pasture. The supplementation frequency doesn't affect DMI, the digestibility and the performance of bovine... (Complete abstract, click electronic access below)
33

\"Avaliação dos resultados analíticos de hidrocarbonetos como instrumento jurídico em caso de derrames de petróleo: mangue de Bertioga\" / Evaluation of analytical results of hydrocarbons as judicial instrument in petroleum spills: Bertioga mangrove

Mauricio Antonio Covre Coimbra 26 February 2007 (has links)
A avaliação da presença de hidrocarbonetos de petróleo em mangue na região entre a Estrada Rio-Santos e o Canal Bertioga ? São Paulo ? Brasil foi realizada através da análise de amostras de sedimento coletadas em testemunhos em épocas distintas (2001 e 2005). O rompimento de um oleoduto em outubro de 1983 derramou 3.000.000 litros de petróleo (também analisado) nesse local. Esse óleo desceu pelo Rio Iriri até atingir o Canal de Bertioga, espalhando-se por cerca de 60 quilômetros. Uma batalha jurídica teve início em 1985 e se encontra atualmente em fase de execução da sentença. Neste trabalho foram descritas algumas questões jurídicas envolvendo o derramamento ocorrido e as análises químicas para serem utilizadas como nexo causal. Os hidrocarbonetos foram analisados através da extração com solvente orgânico em sistema Soxhlet e por cromatografia a gás com detecção de ionização de chama (GC-FID) para n-alcanos e alcanos isoprenóides e com espectrometria de massas (GC-MS) para biomarcadores de petróleo e compostos policíclicos aromáticos (CPAs). Os resultados dos hidrocarbonetos alifáticos somente permitiram avaliar a contribuição de origem petrogênica pela presença de mistura complexa não resolvida (UCM) em algumas amostras de sedimentos. Não foi possível avaliar a contribuição petrogênica nos sedimentos baseado nas concentrações de n-alcanos, de alifáticos totais e as relações pristano/fitano, pristano/n-C17 e fitano/n-C18. A relação entre os homólogos e isômeros dos biomarcadores de petróleo, entretanto, indicou a presença do petróleo derramado no mangue depois de duas décadas. As maiores concentrações dos biomarcadores de petróleo foram encontradas na região mais próxima do derramamento e nos topos dos testemunhos. As análises de CPAs nos sedimentos foram importantes para a identificação de compostos mutagênicos e carcinogênicos provenientes do petróleo derramado no mangue. / The evaluation of the presence of hydrocarbons of oil in mangrove in the region between the Rio-Santos Road and Bertioga Channel - São Paulo - Brazil was carried out through the analysis of sediment samples collected in cores in distinct times (2001 and 2005). The disruption of a pipeline in October of 1983 spilled 3,000,000 of liters of petroleum (also analyzed) in that area. That oil has gone down the Iriri River as far as the Bertioga Channel and has spread for about 60 kilometers. A judicial process has been started in 1985 and nowadays it is in the final phase when the sentence will be given by the law court. In this work some legal issues involving the occurred spilling and the chemical analyses have been described to be used as causal nexus. The hydrocarbons have been analyzed through an organic solvent extraction using Soxhlet apparatus and gas chromatography with flame ionization detection (GC-FID) for n-alkanes and isoprenoids alkanes, and with mass spectrometer (GC-MS) for petroleum biomarkers and polycyclic aromatic compounds (PACs). The analysis of the aliphatic hydrocarbons allowed evaluating only the contribution of petrogenic origin through the presence of unresolved complex mixture (UCM) in some sediment samples. It has not been possible to evaluate the petrogenic contribution in the sediments based on the concentrations of n-alkanes, total aliphatic hydrocarbons and the ratios between pristane/n-C17 and phythane/n-C18. The ratio between petroleum biomarker homologous and isomers has indicated the presence of the oil spilled in the mangrove after two decades. The highest concentrations of the petroleum biomarkers have been found in the region next to the spilling and in the top-core samples. The analyses of CPAs in the sediments have been important to the identification of mutagenic and carcinogenic compounds present in the petroleum spilled in the mangrove.
34

Nutrição e ecologia nutricional de cervídeos brasileiros em cativeiro e no Parque Nacional das Emas - Goiás / Nutrition and nutritional ecology of brazilian cervids in captivity and in the Emas National Park - Goias

Alexandre Berndt 26 September 2005 (has links)
Existem poucas informações sobre exigências de energia de cervídeos brasileiros, dificultando o sucesso de manejo e reprodução em cativeiro. O conhecimento das exigências de energia também é importante para determinar os recursos necessários para sua conservação em parques e reservas. O primeiro objetivo deste experimento foi estudar as exigências nutricionais do veado catingueiro (Mazama gouazoubira) em cativeiro. O segundo objetivo foi observar o comportamento alimentar do veado-campeiro (Ozotoceros bezoarticus) no Parque Nacional das Emas (PNE), descrevendo qualitativamente e quantitativamente as principais espécies vegetais utilizadas para o aporte de nutrientes. A determinação das exigências de energia para mantença utilizou 8 veados-catingueiro de ambos os sexos em cativeiro e foi desenvolvida através de dois métodos: a)equilíbrio de peso e b)água duplamente marcada (2H2 18º). Os animais foram dosados com água duplamente marcada (111,8 mg/kgPV para 2H2O e 163,1 mg/kgPV para H2 18O) e amostras de sangue foram coletadas em intervalos de 3 dias, até que 3 ou 4 meias– vidas dos isótopos tenham decorrido (atingindo o limite de detecção em aproximadamente 30 dias após a dosificação). As curvas de desaparecimento dos isótopos em função do tempo foram utilizadas para calcular o “turnover” de CO2 e H2O. Os resultados obtidos pelos dois métodos foram semelhantes (111,4 e 112,0 kcal/kg.75.d) comprovando que a técnica da água duplamente marcada pode ser utilizada em estudos nutricionais de cervídeos. Informações de doses (mg/kgPV) e intervalo máximo entre aplicação e coleta de sangue (30 dias), permitem o uso desta metodologia em estudos futuros em vida livre. No PNE, veados-campeiro já monitorados com radio colares, permitiram a observação de seu comportamento alimentar. O experimento foi realizado em duas épocas distintas (inverno e verão). As espécies foram analisadas quanto à composição nutricional, para estimar valores energéticos assim como consumo de minerais e proteína. As contribuições das diferentes espécies que compõem a dieta dos cervídeos foram estimadas para duas populações em vida livre, uma com acesso apenas a espécies nativas (área central do parque) e outra com acesso às espécies cultivadas na periferia do PNE. Os sinais isotópicos do carbono 13 e os perfis de n-alcanos foram utilizados para quantificar a contribuição das diferentes espécies ingeridas. Os resultados indicaram que os veados-campeiro utilizam uma ampla gama de partes e espécies vegetais. Sua dieta é composta por aproximadamente 78 ítens, divididos em brotos (38,5%), folhas (15,4%), flores (17,9%), botões florais (12,8%), frutos e sementes (15,4%); de 55 diferentes espécies nativas e 7 culturas agrícolas. Há grande diferença no padrão de consumo entre as populações no interior do parque e aquelas que tem possibilidade de selecionar plantas cultivadas pelo homem. As espécies agrícolas podem contribuir com até 46,9% da dieta dos cervídeos da periferia do parque. Este trabalho determinou as exigências de energia de cervídeos brasileiros, validou o uso de uma técnica indireta para futuros estudos em vida livre e descreveu as espécies e partes utilizadas como aporte de nutrientes por cervídeos em vida livre. / There are limited data on energy requirements of brazilian cervids. Thus, it is difficult to succeed in their management and reproduction in captivity. Knowing the energy requirements is also important to determine the necessary nutritional resources for their conservation in parks and reserves. The first objective was to study the nutritional requirements of the grey-brocket deer (Mazama gouazoubira) in captivity. The second objective was to observe the feeding behavior of the pampas-deer (Ozotoceros bezoarticus) in the Emas National Park (ENP), describing qualitatively and quantitatively the main vegetal species used to supply these animals with nutrients. The determination of energy requirements for maintenance used 8 gray-brocket deer of both sexes in captivity and was carried through two methods: a)weight equilibrium and b)double-labeled water (2H2 18O). The animals were dosed with double-labeled water (111.8 mg/kgBW for 2H2O and 163.1 mg/kgBW for H2 18O) and blood samples were collected with 3 days interval, until 3 or 4 half lives of isotopes had occurred (reached limit of detection at approximately 30 days after the dosage). The curves of isotopes disappearance as a function of time were used to calculate the turnover of CO2 and H2O. The results obtained from the two methods were similar (111.4 and 112.0 kcal/kg.75.d) proving the double-labeled water technique may be used in nutritional studies of cervids. Information on doses (mg/kgBW) and maximum interval between injection and blood collection (30days), allow the use of this methodology in future studies with free ranging deer. In the national park, pampas-deer already monitored with radio colars, facilitated the observation of their feeding behavior. The experiment was conducted at two distinct seasons (winter and summer). The species were analyzed for the nutritional composition, to estimate energy values as well as mineral and protein consumption. The contributions of the different species to the diet of the cervids were estimated for two free ranging populations of the national park, one with access only to native species (central area of the park) and another with access to the crop species cultivated in the periphery of the park. The isotopic signals of carbon 13 and profiles of n-alkanes were used to quantify the contribution of different species to supply the energy demands. The results indicated that pampas-deer feeds on a broad spectrum parts and vegetal species. Its diet was composed of approximately 78 different parts, divided in sprouts (38.5%), leaves (15.4%), flowers (17.9%), floral buttons (12.8%), fruits and seeds (15.4%); from 55 different native species and 7 agricultural cultures. There is a great difference in the intake selection patterns between populations in the interior of the park and those that have access to cropland and the opportunity to choose feeding on native or cultivated plants. The agricultural species can contribute with up to 46.9% of deer diet of the park periphery. This work determined the requirements of energy of Brazilian cervids, validated the use of one indirect technique for use in free ranging animals and described the species and parts used to supply nutrients to cervids in the wild.
35

Avaliação do histórico de impactos antrópicos na bacia de drenagem do Lago das Garças (São Paulo-SP), durante o século XX, com base nos estoques de nutrientes, metais pesados e compostos orgânicos em sedimento lacustre / Evaluation of human impact at Garças lake drainage basin (São Paulo, SP) during the 20th Century based in nutrients, heavy metals and organic compounds in lacustrine sediments

Tatiane Araujo de Jesus 07 November 2008 (has links)
O presente estudo visou reconstruir o histórico de impactos antrópicos na bacia de drenagem do Lago das Garças durante o século XX por meio da deposição de contaminantes no compartimento sedimentar. O Lago das Garças está localizado em uma unidade de conservação, Parque Estadual das Fontes do Ipiranga (PEFI), inserida em área altamente povoada e urbanizada da cidade de São Paulo. Dois testemunhos de sedimento (LG05-03 e LG05-04, com 70 cm e 65 cm, respectivamente) foram amostrados mediante auxílio de mergulhadores no ponto mais profundo do reservatório, sendo, posteriormente, fatiados a cada 1 cm. Em LG05-03 foram quantificadas as distribuições verticais de carbono orgânico total (COT), nutrientes totais (NT e PT), hidrocarbonetos policíclicos aromáticos (HPA), hidrocarbonetos alifáticos (n-alcanos), bem como foi feita a classificação granulométrica. Em LG05-04 foi determinada a deposição de metais pesados (Co, Cr, Cu, Fe, Mn, Ni, Pb e Zn) e a geocronologia através do isótopo radioativo \'ANTPOT. 210 Pb\', usando o modelo CIC (Constant Initial Concentration). Os dados foram analisados por meio de análises estatísticas multivariadas (ACP: Análise de Componentes Principais). Com base nas tendências dos dados e na ACP, foi possível estabelecer três fases principais: Fase I: 64-43 cm (~1894-1975): caracterizada por baixas concentrações de nutrientes e contaminantes, sendo possível recuperar níveis préindustriais destes compostos, propostos como valores de referência regionais. Ainda, com base na razão C/N e em razões entre n-alcanos, notou-se, nesta fase o predomínio de aporte de matéria orgânica de origem alóctone; Fase II: 43-26 cm (~1975-1990): aumento abrupto das concentrações de metais pesados e HPA traçadores de veículos automotores, marcando o aumento da poluição atmosférica devido ao grande crescimento econômico do município e maior circulação de veículos na região. Ainda, foi observado aumento gradual das concentrações de NT e PT, atribuídos aos despejos de esgotos não tratados oriundos da Secretaria de Agricultura e Abastecimento e da Fundação Parque Zoológico; Fase III: 26-0 cm (~1990-2005): aumento mais acentuado das concentrações de nutrientes devido aos despejos de esgotos, acarretando em maior eutrofia do sistema, registrada pelo perfil do n-\'C IND.17\'. Pico das concentrações de HPA traçadores do uso de carvão mineral associado às atividades de uma siderúrgica vizinha (Siderúrgica J.L. Alipeti), bem como queda das concentrações destes traçadores coincidindo com mudanças no processo industrial da empresa. Ainda nesta fase notaram-se aumentos expressivos dos teores e fluxos dos HPA traçadores de veículos automotores, corroborando o cenário de aumento vertiginoso da frota de veículos na última década. Desse modo, este estudo contribuiu com o cenário nacional em termos de manejo de bacias hidrográficas urbanas, incluindo registros desde a época pré-revolução industrial no Brasil (~1894) até os dias atuais, demonstrando o potencial do uso de testemunhos lacustres no resgate de informações relativas à contaminação de ecossistemas aquáticos associadas às atividades antropogênicas. / Present study aimed to reconstruct the human impact history on the Garças Lake Drainage Basin during the 20th Century based on contaminants deposition on the lacustrine sediment. Garças Lake is located in a preservation area, the Parque Estadual das Fontes do Ipiranga (PEFI), located in a highly populated urban area within the city of São Paulo. Two sediment cores (LG05-03 and LG05-04, 70 cm and 65 cm long) were sampled by divers at the deepest site of the lake, which were sliced at 1 cm intervals. Information for LG05-03 included total organic carbon (TOC), total nutrients (TN and TP), polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons (n-alkanes) and grain size vertical distributions. Deposition of heavy metals (Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and the geocronology by \'ANTPOT. 210 Pb\', using CIC model (Constant Initial Concentration), were determined in LG05-04. Data were analyzed by multivariate statistic analysis (PCA, principal components analysis). Based on data trends and PCA, it was possible to recognized three main phases: Phase I: 64-43 cm (~1894-1975) characterized by low nutrients and contaminants concentrations, allowing retrieving preindustrial levels of these compounds, which are proposed as regional reference values. Besides, C/N ratio and n-alkanes ratios demonstrated aloctonous organic matter predominance; Phase II: 43-26 cm (~1975-1990) characterized by the abrupt increase of heavy metals and vehicular PAHs concentration, indicating the atmospheric pollution increase, due to the great economic rise experienced by the city of São Paulo over that time and the higher vehicles circulation in the region. Yet, it was observed a gradual increase in nutrient concentration attributed to the untreated sewage inputs from the São Paulo State Department of Agriculture and Provisioning headquarters and the city Zoo; Phase III: 26-0 cm (~1990-2005) characterized by a marked increase in nutrient concentration related to the untreated sewage inputs, leading to the increase of eutrophication, as registered by the n-\'C IND.17\' distribution. A peak of coal PAHs concentration was also noticed, related to a neighbor steel mill (J.L. Aliperti), followed by a subsequent decrease of these compounds, coincident with industrial procedures changes. Besides, there was an expressive increase in vehicular PAHs concentrations, corroborating the scenery of a drastic raise of vehicles in the last decade. The present study contributed to the national scenario towards urban drainage basin management. It included records since preindustrial time (~1894) up to the present, highlighting the potential use of lacustrine sediment on the retrieval of historical environmental changes of aquatic ecosystems and associated anthropogenic impacts.
36

Application of Biomarkers and Compound Specific Stable Isotopes for the Assessment of Hydrology as a Driver of Organic Matter Dynamics in the Everglades Ecosystem

He, Ding 25 June 2014 (has links)
The Everglades is a sub-tropical coastal wetland characterized among others by its hydrological features and deposits of peat. Formation and preservation of organic matter in soils and sediments in this wetland ecosystem is critical for its sustainability and hydrological processes are important divers in the origin, transport and fate of organic matter. With this in mind, organic matter dynamics in the greater Florida Everglades was studied though various organic geochemistry techniques, especially biomarkers, bulk and compound specific δ13C and δD isotope analysis. The main objectives were focused on how different hydrological regimes in this ecosystem control organic matter dynamics, such as the mobilization of particulate organic matter (POM) in freshwater marshes and estuaries, and how organic geochemistry techniques can be applied to reconstruct Everglades paleo-hydrology. For this purpose organic matter in typical vegetation, floc, surface soils, soil cores, and estuarine suspended particulates were characterized in samples selected along hydrological gradients in the Water Conservation Area 3, Shark River Slough and Taylor Slough. This research focused on three general themes: (1) Assessment of the environmental dynamics and source-specific particulate organic carbon export in a mangrove-dominated estuary. (2) Assessment of the origin, transport and fate of organic matter in freshwater marsh. (3) Assessment of historical changes in hydrological conditions in the Everglades (paleo-hydrology) though biomarkes and compound specific isotope analyses. This study reports the first estimate of particulate organic carbon loss from mangrove ecosystems in the Everglades, provides evidence for particulate organic matter transport with regards to the formation of ridge and slough landscapes in the Everglades, and demonstrates the applicability of the combined biomarker and compound-specific stable isotope approach as a means to generate paleohydrological data in wetlands. The data suggests that: (1) Carbon loss from mangrove estuaries is roughly split 50/50 between dissolved and particulate carbon; (2) hydrological remobilization of particulate organic matter from slough to ridge environments may play an important role in the maintenance of the Everglades freshwater landscape; and (3) Historical changes in hydrology have resulted in significant vegetation shifts from historical slough type vegetation to present ridge type vegetation.
37

Computational Study Of Long Chain N-alkane Binary Mixture Adsorption In Silicalite Under Conditions Of High Loading

Ganesh, Hari S 12 1900 (has links) (PDF)
The study of adsorption of n-alkanes in zeolite pores represents both a fundamental problem in molecular thermodynamics and also a problem with substantial industrial importance. Until mid 19th century, adsorption was mainly used for purification processes such as removal of H2S and mercaptans from natural gas and organic matter from water. However, with the emergence of molecular sieves, especially zeolites, adsorption processes have become an attractive alter- native to distillation in large scale separation of mixtures that have low relative volatility into streams each enriched in one of the components. The pore di- ameters of molecular sieves are of the order of molecular diameters and hence selective adsorption can be achieved by both a difference in adsorbate-adsorbent interactions of various species and obstruction by the pore walls to some of the species in the mixture. The existing adsorption theories such as Henry’s law, Langmuir adsorption model and BET isotherm are incapable of predicting the adsorption isotherms of n-alkanes in zeolite pores. The reason is that in microporous adsorbents, the sorbate molecular mechanisms are influenced by geometrical constraints also. This limitation in the use of theory can be overcome by developing a molecular model and using computers to mimic the real system. This nature of simulation is called molecular simulations. With the development of advanced algorithms, improved force-field parameters and very high computational power of present day computers, molecular simulations have become an important tool in studying adsorption on micro-porous materials. Adsorption experiments of mixtures of long chain alkanes into silicalite under liquid phase conditions show selectivity inversion and azeotrope formation. These effects are due to the subtle interplay between the size of the adsorbed molecules and pore topology of the adsorbent. The underlying molecular mechanisms responsible for selective uptake of one of the components cannot be obtained from experiments but can be realized through simulations. Therefore, in this study, the selective uptake of lighter component during liquid phase adsorption of C14/C15 and C15/C16 n-alkane binary mixtures in the zeolite silicalite is understood through configurational bias grand canonical Monte Carlo (CB- GCMC) molecular simulation technique and a course-grained siting analysis. The simulations are conducted under conditions of low and high loading. The siting pattern of the adsorbates inside the zeolite pores is used to explain the selectivity as seen in experiments.
38

Investigação da introdução da matéria orgânica no sedimento do Rio Paraibuna e o papel dos hidrocarbonetos alifáticos como marcadores biogeoquímicos no monitoramento de contaminações antrópicas

Araujo, Fausto Moreira 20 March 2015 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-18T17:00:14Z No. of bitstreams: 1 faustomoreiraaraujo.pdf: 3458303 bytes, checksum: 1018968a4d60b355a7d1902eb73fe9b7 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-01-25T15:35:15Z (GMT) No. of bitstreams: 1 faustomoreiraaraujo.pdf: 3458303 bytes, checksum: 1018968a4d60b355a7d1902eb73fe9b7 (MD5) / Made available in DSpace on 2016-01-25T15:35:15Z (GMT). No. of bitstreams: 1 faustomoreiraaraujo.pdf: 3458303 bytes, checksum: 1018968a4d60b355a7d1902eb73fe9b7 (MD5) Previous issue date: 2015-03-20 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho foi realizada a determinação de hidrocarbonetos alifáticos (n-alcanos e isoprenóides) marcadores biogeoquímicos do petróleo e de seus derivados, em amostras de sedimento do rio Paraibuna. A amostragem foi feita para 16 pontos ao longo do rio no município de Juiz de Fora-MG, coletados com draga Petersen. Para a extração dos analitos da matriz, realizou-se otimização da condição de extração por planejamento Box-Bahnken 33 por ultrassom. A condição escolhida para extrair os analitos foi de um tempo de sonicação de 10 minutos, com 10 mL de solvente e composição da mistura de solventes composta por n-hexano e acetona (25:75). Os extratos foram eluidos em coluna de adsorção constituída por sílica, alumina e sulfato de sódio utilizando 16 mL de n-hexano para total eluição dos extratos. A análise do eluato foi realizada pela técnica de cromatografia a gás acoplada à espectrometria de massas. Para complemento dos resultados, foi determinado a granulometria do sedimento e teores de carbono orgânico total (COT) em cada ponto. Obteve-se forte correlação do COT, com os teores de silte + argila. De maneira geral, o sedimento do rio Paraibuna é basicamente constituído por areia. Para pontos que o teor de silte e argila foram baixos, não foi possível a quantificação de vários analitos. A concentração de alifáticos totais encontrada variou de 0,78 a 1318,18 μg g-1 peso seco, e de n-alcanos totais de 0,07 a 5,49 μg g-1 peso seco, sendo observado um aumento da concentração dos compostos ao longo do rio na direção e sentido de seu fluxo. O índice preferencial de carbono obtido abrangeu de 0,94 a 4,75, indicando introdução de n-alcanos no sedimento do rio por fontes antrópicas para algumas amostras. Dos 16 pontos coletados, 12 apresentaram mistura complexa não resolvida, sendo 50% de perfil unimodal, e 50% bimodal, em decorrência de poluição por combustíveis e derivados do petróleo. A razão terrestre/aquática associada com a razão C31/C19 apontaram domínio das contribuições terrígenas por plantas vascularizadas para todos os pontos coletados. / In this work, it was performed the determination of n-alkanes (C10-C40) biomarkers crude oil and its derivatives, in river sediment samples. The sampling was performed with 16 points along Paraibuna river in Juiz de Fora-MG, collected with Petersen dredge. A 33 Box-Behnken experimental design was used to optimize the ultrasound-assisted extraction conditions. The optimized conditions was 10 minutes of sonication with 10 mL solvent mixture and the mixture composition was n-hexane and acetone (25:75). The extracts were eluted in an adsorption column containing silica, alumina and sodium sulfate, using 16 mL of n-hexane for total elution of the extract. The eluated analysis was performed by gas chromatography coupled with mass spectrometry. In addition, it was verified the sediment granulometry and the total organic carbon (TOC) determination for each sampling. We obtained a strong correlation between TOC and the silt + clay. In general, Paraibuna river’s sediment are basically constituted by sand. For points that the concentration of silt + clay were low, it was not possible to detect several analytes. The concentration of total aliphatic ranged from 0.78 to 1318.18 μg g-1 dry weight and the total n-alkanes ranged from 0.07 to 5.49 μg g-1 dry weight, being observed an increase in the concentration of compounds in the direction of river flows. The obtained carbon preference index ranged from 0.94 to 4.75, indicating introduction of n-alkanes by anthropogenic sources for some samples. From the 16 collected points, 12 presented an unresolved complex mixture, being 50% of unimodal profile and 50% bimodal, as result of pollution from fuel oil and other petroleum derivatives. In all points, it was observed the domain of terrigenous sources contributions over the aquatic sources.
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Avaliação da influência do canal do Valo Grande na composição molecular e isotópica da matéria orgânica depositada no Sistema Estuarino-Lagunar de Cananéia-Iguape-SP / The influence of Valo Grande channel on the molecular and isotopic composition of the organic matter in Cananéia-Iguape Estuarine-Lagoon System

Barbosa, Ana Cecilia Rizzatti de Albergaria 25 September 2013 (has links)
O objetivo do presente estudo foi avaliar, através da análise de n-alcanos e de suas razões isotópicas, a influência da abertura do canal artificial do Valo Grande (VG) nas fontes de matéria orgânica (OM) do Sistema Estuarino-Lagunar de Cananéia-Iguape (CIELS). Os compostos foram analisados em quatro testemunhos, 22 sedimentos superficiais e em folhas de nove espécies de plantas dominantes na região de estudo. Os parâmetros avaliados nas folhas amostradas permitiram separar as espécies estudadas em monocotiledôneas e dicotiledôneas, e em vegetação lenhosa de mangue e de restinga. Esta separação foi útil na identificação das fontes de OM do CIELS. Os dados dos sedimentos superficiais mostraram que a principal fonte de OM no sistema é a vegetação de restinga. Esta se dá principalmente na região norte, onde está presente o VG. A influência fitoplanctônica, das macrófitas emersas e da vegetação de mangue é maior na região sul. Os dados dos testemunhos mostraram que a abertura do VG aumentou a contribuição da vegetação de restinga e das macrófitas aquáticas na OM presente ao longo do CIELS, diminuindo a influência fitoplanctônica e das macrófitas emersas. Assim, a qualidade e quantidade de OM do CIELS foram influenciadas pela presença do VG. / This study aimed to verify, through the use of n-alkanes and their isotopic composition, the influence of the Valo Grande artificial channel (VG) on organic matter (OM) sources of the Cananéia-Iguape Estuarine-Lagoon System (CIELS). The compounds were analyzed in four cores, 22 surface samples and nine dominants plants species leaves sampled on the studied area. The parameters evaluated on the leaves permitted to group the studied species in mono and dicotyledonous, and in mangrove and resting vegetation. This was useful to identify the OM sources on the CIELS. The surface sediment data showed that the CIELS OM is mainly composed by restinga vegetation. This occurs mainly on the northern region, where the VG is present. The influence of phytoplankton, of emergent macrophytes and of mangrove trees is higher on the southern region. The cores data showed that the VG opening increased the influences of Atlantic Forest and aquatic macrophytes on the CIELS OM, decreasing the emergent macrophytes and the phytoplankton influence. So, the type and the amount of OM on the CIELS are influenced by the VG presence.
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Mixed grazing of sheep and cattle using continuous or rotational stocking

Kitessa, Soressa Mererra January 1997 (has links)
Two consecutive experiments were conducted to test a hypothesis that mixed grazing outcome is influenced by the type of stocking system applied. The objective of both experiments was to investigate the influence of co-grazing with sheep on cattle liveweight gain (LWG) under continuous (C) and rotational (R) stocking, where sheep weekly liveweight change under the two stocking systems was kept similar. In experiment I nine yearling heifers (266 ± 4.5 kg liveweight) and 27 ewe hoggets (54±0.9 kg liveweight) were continuously stocked for 19 weeks on an irrigated perennial ryegrass-white clover pasture (2.95 ha) maintained at a sward surface height (SSH) of 5cm by adding or removing additional animals in a fixed ratio (1: 1 W⁰.⁷⁵ cattle:sheep). An equal area of pasture was rotationally stocked by a similar group of animals where they received a new area of pasture daily and also had access to the grazed area over the previous 2 days. The size of the new area provided daily was such that the weekly liveweight change of rotationally co-grazed sheep was equal to that of those continuously co-grazed with cattle. Similar groups of animals were used in the second experiment with additional group of 9 heifers grazed alone on C and R pastures. Liveweight of animals was recorded weekly and final fasted weight was determined after 24-hour total feed restriction. SSH on both treatment swards was recorded daily. There were three intake measurement periods spread over the trial period. Organic matter intake (OMI) was predicted from the ratio of N-alkanes in faeces and herbage. Diet composition was determined by dissecting oesophageal extrusa samples. Grazing behaviour (bite rates and grazing time) were also recorded. The mean SSH for C pasture was 5.1±0.09 cm. Overall pre- and post-grazing SSH for R pasture was 15.9 ±0.12 and 5.6 ±0.07 cm, respectively. As determined by the protocol average daily LWG of sheep was similar between C and R (147 (±5.8) vs 138 (±6.7) g day⁻¹; (P>0.05). In contrast, cattle continuously stocked with sheep grew 200 g day⁻¹ slower than those rotationally stocked with sheep (800 (±41.6) vs 1040 (±47.7) g day⁻¹, P<0.0l). R heifers achieved 30 kg higher final fasted liveweight than C heifers (350 vs 381 kg; P<0.01). Overall LWG per ha was also 6 % higher under R than C stocking (674 vs 634 kg ha⁻¹). The OMD of both sheep (73.5 vs 75.8 %) and cattle (75.8 vs 78.0 %) diets was similar under continuous and rotational stocking. There was no significant difference OMI data also concurred with the L WG data (Cattle: 7.94 vs 6.31 (±0.32) kg day⁻¹ (P<0.05); sheep: 1.40 vs 1.44 (±0.04) kg day⁻¹ for Rand C treatments, respectively). There was no difference in clover content of cattle diet under C and R treatments. C heifers had higher number of bites per minute than R heifers (62 vs 56; P<0.05). Proportion of heifers seen grazing (every 15-minute) during four 24-hour observations was greater on C than R pasture (0.44 vs 0.31 (±0.03); P<0.05). The similarity coefficient between sheep and cattle diet was 0.61 and 0.76 under C and R stocking, respectively. The lower daily LWG of C heifers was attributed to (a) the lower SSH under C than R stocking and/or (b) the inability of cattle to compete well with sheep where there is small, continual renewal of resources (C) in contrast to a large periodic renewal under R stocking. This experiment showed that the outcome of mixed gruing can be influenced by the stocking system chosen. But it was not possible to apportion the difference in LWG of cattle between mixed grazing per se and the difference in mean grazed sward height (5.1 for C vs 10.8 cm for R). A second experiment was conducted to determine the relative performance of cattle co-grazed with sheep (CS) and grazed alone (CA) under each stocking system. Hence, there were four treatments. CA- continuous stocking (CA-C), CS- continuous stocking (CS-C), CA- rotational stocking (CAR) and CS- rotational stocking (CS-R). A total area of 4.42 ha was allocated to each stocking system. Under C stocking, 2.95 ha (2/3) was assigned to CS-C and 1.47 ha (1/3) to CA-C, and SSH on both treatments was kept at 4 cm by adding or removing extra animals. Under R stocking, CA-R and CS-R grazed side by side separated by an electric fence. They were given a fresh area daily, the size of which was varied such that the weekly LW change of R sheep was equal to that of the C sheep. CA-R received one-third of the new area though the size was adjusted regularly to achieve the same post-grazing SSH with CS-R. Measurements included: weekly liveweight change, OMI (two periods) and diet composition (using N-alkanes). The mean SSH of CA-C and CS-C swards was 4.27 and 4.26 (±0.02) cm, respectively. CA-R and CS-R swards had mean pre-grazing SSH of 14.9 and 15.2 (±0.08) cm and post-grazing heights of 4.87 and 4.82 cm (±0.03), respectively. The proportion of areas infrequently grazed was higher for CA-C than CS-C swards (0.22 vs 0.17, respectively). C and R sheep daily LWG: 155 (±0.6) and 147 (±0.7) g, and OMI: 1.96 and 2.04 (±0.ll) kg, respectively, were not significantly different. They also had similar diet composition. In comparison, CS-C heifers grew only at 69 % of the daily LWG achieved by CS-R heifers (706 vs 1028 (±72) g; P<0.05). LWG of CA-C and CA-R was 916 and 1022 (±72) g day⁻¹, respectively. The difference in LWG between CS-R and CS-C (D₁) heifers was due to difference in mean sward height, stocking system and mixed grazing, while D₂ (difference in LWG between CA-R and CAC) was due to difference in mean sward height and stocking system. D₁-D₂ (the effect of stocking system on mixed grazing) was 216 g and made up 67 % of the total difference between CS-R and CS-C. There was a significant stocking system-species mixture interaction in the final fasted LW achieved by heifers. Final fasted LW was significantly lower for CS-C than CA-C heifers (283 vs 323 (±9.7) kg), but did not differ between CS-R and CA-R (332 vs 330 (±9.7) kg, respectively). The digestibility of diet OM was similar for both continuously and rotationally stocked sheep (84.4 vs 83.2 %, respectively). Cattle diet OMO was 76.5, 74.7, 79.4 and 77.8 for CA-C, CS-C, CA-R and CS-R respectively (P>0.05). Differences in OMI followed a similar pattern to daily LWG. Mean daily OMI was 8.98, 6.24, 8.80 and 9.45 (±0.40) kg for CA-C, CS-C, CA-R and CS-R, respectively. Clover content of the diet of CA-C heifers was three times higher than that of CS-C heifers (30.7 vs 10.4 % OM; P<0.05); there was no difference in clover content of diets of CS-R and CA-R heifers (21.5 vs 23.9 % OM, respectively). In both stocking systems LWG per ha was higher on CA than CS treatments. These results suggested that the disadvantage of selective clover grazing by sheep outweighed the advantages of sheep grazing around cattle dung patches under continuous stocking. Under rotational stocking, rapid diurnal changes in sward conditions probably limited selective grazing by both sheep and cattle such that there was no disadvantage to CS cattle. The results do not provide a basis for recommending grazing cattle with sheep rather than cattle alone, but do provide some basis for recommending co-grazing of sheep and cattle using rotational rather than continuous stocking.

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