Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-06-30T18:09:29Z No. of bitstreams: 1 TES_STEFANI_ALTENHOFEN_PARCIAL.pdf: 820184 bytes, checksum: 93540eb7fece868ec872a31e8f894852 (MD5) / Approved for entry into archive by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-06-30T18:09:36Z (GMT) No. of bitstreams: 1 TES_STEFANI_ALTENHOFEN_PARCIAL.pdf: 820184 bytes, checksum: 93540eb7fece868ec872a31e8f894852 (MD5) / Made available in DSpace on 2017-06-30T18:09:44Z (GMT). No. of bitstreams: 1 TES_STEFANI_ALTENHOFEN_PARCIAL.pdf: 820184 bytes, checksum: 93540eb7fece868ec872a31e8f894852 (MD5) Previous issue date: 2017-03-06 / Neurotoxic agents, such as pesticides, organic solvents and metals, are capable to alter normal CNS activity. Manganese (Mn) is a metal found in the environment, which when in excess, accumulates in the CNS making it a potential hazard to health. In addition to Mn, other neurotoxic agents can cause changes, leading to deficits in neurotransmission systems. The growth of crop pests has exponentially increased the use of agrochemicals to maintain plantations. The fungicide tebuconazole is a triazole used in crops, such as barley, wheat, peanuts and orchard fruits and related to behavioral and oxidative changes. The insecticide dichlorvos, belongs to organophosphate family, acts through the acetylcholinesterase (AChE) inhibition, leading to hyperstimulation of cholinergic receptors. Cholinergic system is characterized by the action of acetylcholine (ACh) on muscarinic and nicotinic receptors. The level of this molecule is regulated by acetylcholinesterase (AChE), which catalyzes degradation of ACh into choline and acetate. Purinergic system is characterized by the action of ATP and adenosine on purinoreceptor P2 and P1, respectively. The levels of these molecules are regulated by ectonucleotidases, which constitute the extracellular cascade for ATP hydrolysis to adenosine. Adenosine can be subsequently deaminated to inosine by action of adenosine deaminase (ADA). Dopamine (DA), synthesized from L-DOPA, is the neurotransmitter of the dopaminergic system and it acts through its D1-D5 receptors, controlling the start and execution of movement. This study aims to evaluate the effects of exposure to manganese and pesticides, such as dichlorvos and tebuconazole, on behavioral parameters in larval and adult zebrafish, as well as its effects on purinergic, cholinergic and dopaminergic signaling. Exposure to MnCl2 in the early stages of development (1 hpf - 5 dpf) was able to reduce the distance traveled, absolute turn angle and mobile time of the larvae at 5, 7 and 10 dpf. In addition, it caused an increase in TH levels at 5 and 7 dpf, followed by a reduction at 10 dpf. There was also an increase in markers of cell death. In adult animals, exposure during 96 hours caused a reduction in distance traveled, number of line crossings and absolute turn angle, and an inhibition on memory acquisition through the inhibitory avoidance task. In addition, adult animals exposed to MnCl2 showed increased levels of markers of cell death, TH and DOPAC (3,4-dihydroxyphenylacetic acid) in the brain. The 96-hour exposure to this metal was also able to inhibit the NTPDases and ecto-ADA activities and to reduce ADA2.1-mRNA transcripts, besides for increasing ADP levels and reducing the amount of AMP, ADO and INO in the incubation medium. Tebuconazole was able to increase the ocular distance of larvae at 5 dpf and reduce the exploratory behavior of these animals, and still decrease the locomotor activity of 96 hours exposed adult zebrafish. Moreover, this fungicide decreased AChE activity in both 5 dpf larvae and brains of adult animals. Exposure to dichlorvos (1 hpf - 7 dpf) reduced body length, heartbeat rate and larval surface at 7 dpf as well as affected the escape capacity of larvae at 7 and 14 dpf. Further, it reduced exploratory behavior at 7 and 14 dpf, maintaining this pattern when animals became young adults at 30 dpf, and adults at 70 dpf. However, the analysis performed at 120 dpf showed a recovery of behavioral activity equal to the control. In addition, the analysis of exposure to dichlorvos in the early stages of development at 120 dpf on the enzymes of the purinergic system, showed that this insecticide is able to elevate the ecto-5'-nucleotidase activity and reduce the ecto-ADA activity. The results showed that neurotoxic agents, such as Mn, dichlorvos and tebuconazole, play a role in the larval and adult behavior of zebrafish, and affect different neurotransmission systems. Such behavioral changes may be associated with the deficits observed in neurochemical and molecular mechanisms investigated. / Agentes neurot?xicos, tais como pesticidas, solventes org?nicos e metais, s?o capazes de alterar a atividade normal do Sistema Nervoso Central (SNC). O mangan?s (Mn) ? um metal encontrado no ambiente que, quando em excesso, acumula-se no SNC, tornando-se um perigo potencial para a sa?de. Al?m do Mn, outros agentes neurot?xicos podem causar altera??es, levando a d?ficits em sistemas de neurotransmiss?o. O crescimento de pragas de lavoura tem aumentado exponencialmente o uso de agrot?xicos para manuten??o de planta??es. O fungicida tebuconazol ? um triazol utilizado em culturas como a cevada, trigo, amendoim e frutas do pomar e relacionado com altera??es comportamentais e oxidativas. O inseticida dicl?rvos, pertence a fam?lia dos organofosforados atuando atrav?s da inibi??o da acetilcolinesterase (AChE), que leva ? hiperestimula??o dos receptores colin?rgicos. O sistema colin?rgico ? caracterizado pela a??o da acetilcolina (ACh) nos receptores muscar?nicos e nicot?nicos. O n?vel dessa mol?cula ? regulado pela acetilcolinesterase (AChE), que catalisa a degrada??o da ACh em colina e acetato. O sistema purin?rgico ? caracterizado pela a??o do ATP e adenosina (ADO) nos purinoreceptores P2 e P1, respectivamente. Os n?veis dessas mol?culas s?o regulados pela a??o das ectonucleotidases que catalisam a hidr?lise do ATP a adenosina (ADO). A ADO pode ser desaminada a inosina (INO) pela a??o da adenosina desaminase (ADA). A dopamina (DA), sintetizada a partir da L-DOPA, ? o neurotransmissor do sistema dopamin?rgico e age atrav?s dos seus receptores D1-D5, controlando o in?cio e execu??o do movimento. Portanto, este estudo visa avaliar os efeitos da exposi??o ao mangan?s e agrot?xicos, tais como dicl?rvos e tebuconazol, sobre par?metros comportamentais em peixe-zebra nos est?gios larval e adulto, bem como os seus efeitos sobre a sinaliza??o purin?rgica, colin?rgica e dopamin?rgica. A exposi??o ao MnCl2 nos est?gios iniciais de desenvolvimento (1 hpf - 5 dpf) foi capaz de reduzir a dist?ncia percorrida, o ?ngulo de giro absoluto e o tempo de mobilidade das larvas aos 5, 7 e 10 dpf. Al?m disso, causou um aumento nos n?veis de TH aos 5 e 7 dpf, seguido por uma redu??o em 10 dpf. Tamb?m foi observado um aumento dos marcadores de morte celular. Em animais adultos, a exposi??o ao longo de 96 horas causou redu??o na dist?ncia percorrida, n?mero de cruzamentos e ?ngulo de giro absoluto, e ainda uma redu??o na aquisi??o de mem?ria atrav?s da tarefa de esquiva inibit?ria. Al?m disso, os animais adultos expostos a MnCl2 apresentaram aumento nos n?veis de marcadores de morte celular, al?m de TH e DOPAC (?cido 3,4-di-hidroxifenilac?tico) no enc?falo. A exposi??o por 96 horas a este metal tamb?m foi capaz de inibir a atividade das NTPDases e da ecto-ADA e reduzir os transcritos de RNAm do gene ADA2.1, al?m de aumentar os n?veis de ADP e reduzir a quantidade de AMP, ADO e INO no meio. O tebuconazol foi capaz de aumentar a dist?ncia ocular de larvas aos 5 dpf e reduzir a capacidade explorat?ria desses animais, e ainda diminuir a atividade locomotora de peixe-zebra adultos expostos por 96 horas. Al?m disso, este fungicida diminuiu a atividade da AChE tanto em larvas de 5 dpf, quanto em enc?falo de animais adultos. Al?m do mais, o tebuconacol aumentou a express?o relativa de mRNA da AChE em larvas, no entanto, n?o alterou em adultos. A exposi??o ao dicl?rvos, nas fases iniciais do desenvolvimento (1 hpf - 7 dpf), reduziu o tamanho corporal, a taxa de batimentos card?acos e a superf?cie dos olhos de larvas de 7 dpf, bem como afetou a capacidade de escape de larvas aos 7 e 14 dpf. Al?m disso, reduziu a capacidade explorat?ria aos 7 e 14 dpf, padr?o mantido quando os animais tornaram-se adultos jovens aos 30 dpf, e adultos aos 70 dpf. No entanto, as an?lises realizadas aos 120 dpf mostraram recupera??o da atividade comportamental similar ao grupo controle. A an?lise aos 120 dpf da exposi??o ao dicl?rvos nas fases iniciais do desenvolvimento sobre as enzimas do sistema purin?rgico mostrou que este inseticida ? capaz de elevar a atividade da ecto-5?-nucleotidase e reduzir a atividade da ecto-ADA. Os resultados mostram que os agentes neurot?xicos, tais como Mn, dicl?rvos e tebuconazol t?m atua??o significativa sobre o comportamento do peixe-zebra em est?gio larval e adulto, al?m de afetar diferentes sistemas de neurotransmiss?o. Tais altera??es comportamentais podem estar associadas aos d?ficits observados nos mecanismos neuroqu?micos e moleculares investigados.

?rea de concentra??o: Qu?mica Anal?tica / Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-10T11:52:19Z No. of bitstreams: 2 Disserta??o Saimon Final.pdf: 1908777 bytes, checksum: 648b40c0f18a1ca3e51ec915751f4ad7 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-10T13:00:28Z (GMT) No. of bitstreams: 2 Disserta??o Saimon Final.pdf: 1908777 bytes, checksum: 648b40c0f18a1ca3e51ec915751f4ad7 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-10T13:00:35Z (GMT) No. of bitstreams: 2 Disserta??o Saimon Final.pdf: 1908777 bytes, checksum: 648b40c0f18a1ca3e51ec915751f4ad7 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-12T17:52:34Z (GMT) No. of bitstreams: 2 Disserta??o Saimon Final.pdf: 1908777 bytes, checksum: 648b40c0f18a1ca3e51ec915751f4ad7 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Made available in DSpace on 2014-12-12T17:52:34Z (GMT). No. of bitstreams: 2 Disserta??o Saimon Final.pdf: 1908777 bytes, checksum: 648b40c0f18a1ca3e51ec915751f4ad7 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Previous issue date: 2013 / Item withdrawn by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-19T13:51:37Z Item was in collections: PPGQ - Mestrado em Qu?mica (Disserta??es) (ID: 150) No. of bitstreams: 3 Dissertacao_Saimon_Final.pdf: 1908777 bytes, checksum: 648b40c0f18a1ca3e51ec915751f4ad7 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_Saimon_Final.pdf.txt: 148365 bytes, checksum: 0a99c3be8d2cda4ce737a53a561cf7a5 (MD5) / Item reinstated by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-19T13:53:14Z Item was in collections: PPGQ - Mestrado em Qu?mica (Disserta??es) (ID: 150) No. of bitstreams: 3 Dissertacao_Saimon_Final.pdf: 1908777 bytes, checksum: 648b40c0f18a1ca3e51ec915751f4ad7 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_Saimon_Final.pdf.txt: 148365 bytes, checksum: 0a99c3be8d2cda4ce737a53a561cf7a5 (MD5) / O presente trabalho descreve o desenvolvimento de um sensor voltam?trico seletivo e sens?vel para a determina??o simult?nea de catecol (CC) e hidroquinona (HQ) usando um eletrodo de carbono v?treo (ECV) modificado com ftalocianina de mangan?s (MnPc) adsorvida sobre nanotubos de carbono de paredes m?ltiplas (NTCPM). O eletrodo modificado apresentou uma excelente atividade eletroqu?mica tanto para oxida??o quanto para a redu??o de CC e HQ. No ECV/NTCPM/MnPc tanto CC, quanto HQ podem gerar um par redox quase-revers?vel e picos bem definidos. Sob as condi??es experimentais e operacionais otimizadas, a corrente de pico cat?dica foi linear na faixa de 1,0 x 10-6 mol L-1 a 6,0 x 10-4 mol L-1 para ambos, CC e HQ, com limites de detec??o de 0,95 e 0,41 ?mol L-1, respectivamente. Adicionalmente, as correntes de pico an?dicas foram linear na faixa de 1,0 x 10-6 mol L-1 a 6,0 x 10-4 mol L-1 para ambos, CC e HQ, com limites de detec??o de 0,96 e 0,48 ?mol L-1, respectivamente. O m?todo proposto foi eficazmente aplicado na detec??o simult?nea de hidroquinona e catecol em amostras de ?gua. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Qu?mica, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2012. / ABSTRACT The present work describes the development of a selective and sensitive voltammetric sensor for catechol (CC) and hydroquinone (HQ) using a glassy carbon (GC) electrode modified with manganese phthalocyanine (MnPc) adsorbed on multiwalled carbon nanotubes (MWCNT). The modified electrode showed an excellent electrochemical activity towards the oxidations and reductions of CC and HQ. At the GC/MWCNT/MnPc electrode both CC and HQ can generate a pair of quasi-reversible and well-defined redox peaks. Under the optimized experimental and operational conditions, the cathodic peak current was linear over the 1.0 x 10-6 mol L-1 to 6.0 x 10-4 mol L-1 range for both CC and HQ, with detection limits of 0.95 and 0.41 ?mol L-1, respectively. In addition, anodic peak current were linear over the 1.0 x 10-6 mol L-1 range to 6.0 x 10-4 mol L-1 for both CC and HQ, with detection limits of 0.96 and 0.48 ?mol L-1, respectively. The proposed method was effectively applied to the simultaneous detection of hydroquinone and catechol in water samples.

Made available in DSpace on 2014-12-17T15:01:17Z (GMT). No. of bitstreams: 1 AnaPCC_Restricao_total.pdf: 752303 bytes, checksum: 654aeb93235755a52cbaf1212dfece64 (MD5) Previous issue date: 2009-02-19 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this work is the addition of a metallic ion, of the metal Manganese, in a clay of Rio Grande do Norte state for structural ceramics use, the objective this study was to assess the evolution of ceramic properties. The clay was characterized by Chemical and Thermal analysis and Xray difraction. The metallic ion was added in the clay as aqueous solutions at concentrations of 100, 150 and 200 mg / L. The molded by extrusion and the burned were temperatures at 850, 950, 1050 and 1150 ? C. Was made Chemical Analysis and investigated the following parameters environmental and ceramic: Solubility, Colour, Linear Retraction (%), Water Absorption (%), Gresification Curves, Apparent Porosity (%), Apparent Specific Mass (g/cm3) and Flexion Rupture Module (kgf/cm2). The results showed that increasing the concentration of metallic ion, properties such as Apparent Porosity (%), Water Absorption (%) decreases and the Flexion Rupture Module (kgf/cm2) increases with increasing temperature independent of the concentration of the ion. The gresification curves showed that the optimum firing temperatures were in the range between 950 and 1050 ? C. The evaluation of the properties showed that the ceramic material can be studied its use in solid brick and ceramic materials with structural function of filling. The results of solubility showed that the addition of ion offers no risk to the environment / Neste trabalho estudou-se a adi??o de um ?on met?lico, Mangan?s bivalente, em uma argila do Rio Grande do Norte para uso em cer?mica estrutural, tendo como objetivo avaliar a evolu??o das propriedades cer?micas e ambientais. A argila foi caracterizada por An?lise Qu?mica (FRX) e Difratograma de Raios X (DRX). O ?on met?lico foi adicionado ? argila na forma de solu??es aquosas nas concentra??es de 100, 150 e 200 mg/L. A moldagem foi por extrus?o e a queima foi realizada nas temperaturas de 850, 950, 1050 e 1150 ?C respectivamente. Fez-se a An?lise Qu?mica de corpos queimados, e os ensaios ambientais de Solubilidade e cer?micos de Cor, Retra??o Linear (%), Absor??o de ?gua (%), Curvas de Gresifica??o, Porosidade Aparente (%), Massa Espec?fica Aparente (g/cm3) e Tens?o de Ruptura ? Flex?o (Kgf/cm2) para os corpos queimados. Os resultados mostraram que aumentando a concentra??o do ?on met?lico, propriedades como Porosidade Aparente (%), Absor??o de ?gua (%) diminuem e a Tens?o de Ruptura ? Flex?o (Kgf/cm2) cresce com o aumento da temperatura independente da concentra??o do ?on. As curvas de gresifica??o mostraram que as temperaturas ?timas de queima ficaram no intervalo compreendido entre 950 e 1050 ?C. A avalia??o das propriedades cer?micas demonstrou que o material estudado ? poss?vel seu uso em tijolo maci?o cer?mico e materiais com fun??o de preenchimento estrutural. Os resultados de solubilidade revelaram que a adi??o do ?on n?o oferece risco ao meio ambiente

Made available in DSpace on 2014-12-17T15:41:59Z (GMT). No. of bitstreams: 1 Mariele ISM_DISSERT.pdf: 4704397 bytes, checksum: 9fa1538bc3d6948d492f9a6c378eaf62 (MD5) Previous issue date: 2012-07-20 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Processo de Dessulfuriza??o Oxidativa (ODS) de um diesel comercial foi realizado em condi??es suaves na presen?a de catalisadores a base de van?dio ou mangan?s, suportados em aluminas, argilas e ze?litas. A oxida??o e extra??o da mol?cula de dibenzotiofeno (DBT), representando os compostos de enxofre presentes no diesel, foram realizadas usando como solvente a acetonitrila e oxidante o per?xido de hidrog?nio a temperatura de 55?C. O processo mostrou-se eficiente, o DBT foi convertido para sua respectiva sulfona, e a quantidade que n?o foi convertida a sulfona foi extra?da pelo solvente. O sistema de rea??o apresentou remo??o e oxida??o de at? 100% do composto de enxofre com alguns catalisadores. Verificando que para a oxida??o os catalisadores foram mais ativos, e os catalisadores de mangan?s apresentaram melhores resultados na extra??o dos compostos de enxofre.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-28T19:07:36Z No. of bitstreams: 1 TiagoRobertoDaCosta_TESE.pdf: 4624767 bytes, checksum: b882489e2f56b6e0d740f5f1aaf85b08 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-28T23:57:17Z (GMT) No. of bitstreams: 1 TiagoRobertoDaCosta_TESE.pdf: 4624767 bytes, checksum: b882489e2f56b6e0d740f5f1aaf85b08 (MD5) / Made available in DSpace on 2017-03-28T23:57:17Z (GMT). No. of bitstreams: 1 TiagoRobertoDaCosta_TESE.pdf: 4624767 bytes, checksum: b882489e2f56b6e0d740f5f1aaf85b08 (MD5) Previous issue date: 2016-08-05 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A matriz energ?tica mundial ? basicamente constitu?da a base de combust?veis f?sseis, sendo que diferentes estudos indicam que nas pr?ximas d?cadas n?o haver? mudan?as significativas nesse cen?rio e isso impacta de modo significativo no meio ambiente, pois a queima desses combust?veis para gera??o de energia produz bastante CO2. Sendo o di?xido de carbono o principal g?s de origem antropog?nica, respons?vel pela intensifica??o do efeito estufa. Devido a isso, cientistas e pol?ticos de todo mundo tem sugerido diversas medidas e tecnologias que objetivam a diminui??o das emiss?es de CO2 na atmosfera para as pr?ximas d?cadas. Entre as tecnologias, a Captura e Armazenamento de CO2 (CAC) tem tido um destaque especial nos ?ltimos anos. Estudos realizados pela Ag?ncia Internacional de Energia (International Energy Agency-IEA) quanto o Painel Intergovernamental sobre Mudan?as Clim?ticas (IPCC), sugerindo diversos cen?rios de crescimento econ?micos e de demanda energ?tica, indicam que na maioria dos casos as tecnologias de captura e armazenamento do CO2 contribuem entre 10-55% do esfor?o mundial para reduzir as concentra??es de CO2 na atmosfera at? 2100. Nesse contexto, a combust?o indireta com transportadores s?lidos de oxig?nio (processo Chemical-Looping Combustion-CLC), ? considerada uma das melhores alternativas para reduzir os custos da captura do CO2, principalmente quando comparadas aos processos convencionais, pois n?o necessita da separa??o do CO2 do N2, pois o combust?vel n?o ? misturado diretamente com ar ou oxig?nio. Esta tese de doutorado est? focada no desenvolvimento de cinco transportadores de oxig?nio ? base de mangan?s, os quais foram primeiramente caracterizados com objetivo de determinar quais deles s?o mais promissores para serem avaliados em processos de CLC. As t?cnicas e metodologias de caracteriza??es utilizadas durante a primeira etapa foram: porosimetria por inje??o de merc?rio, resist?ncia ? fratura, difra??o de raios X (DRX), redu??o e oxida??o ? temperatura programada (TPR e TPO), capacidade de transporte de oxig?nio (Roc), composi??o qu?mica, reatividade por termogravimetria e ?ndice de velocidade. Conclu?da essas etapas, verificou-se que os transportadores Mn-ZrMF e Mn-ZrSG apresentaram propriedades apropriadas para serem avaliados em um reator de leito fluidizado descont?nuo, onde os experimentos se assemelham ?s condi??es de CLC. Ao fim dos testes no reator, os transportadores de oxig?nio foram submetidos a algumas t?cnicas de caracteriza??o: DRX, TPR e MEV (Microscopia Eletr?nica de Varredura). O transportador Mn-ZrMF apresentou problemas de aglomera??o durante os testes no reator, sendo considerado inapropriado para prosseguir com os experimentos. Por outro lado, o Mn-ZrSG apresentou elevada reatividade com os combust?veis utilizados (CO > H2 > CH4), n?o sendo verificado o problema da aglomera??o, tendo baixa perda por atrito, com vida m?dia superior a 11.000 horas. Esse material ? bastante promissor para seu uso em CLC de combust?veis s?lidos. / The world?s energy matrix is essentially composed of fossil fuels and different studies show indicate that in the next decades there will be no significant changes in this scenario, which impacts significantly on the environment, since the burning of fossil fuels for power generation gives there main contibution to antropogenic CO2 emissions produces greatest amount of CO2. Carbon dioxide is the main anthropogenic gas responsible for intensifying the greenhouse effect. Because of this, scientists and politicians around the world have suggested a number of strategies and technologies to reduce CO2 emissions to the atmosphere for the next decades. Among these technologies, CO2 capture and storage (CCS) has gained attention in recent years. Studies conducted by the International Energy Agency (IEA) and the Intergovernmental Panel on Climate Change (IPCC) suggest various scenarios of economic growth and energy demand, indicating that in most cases the CO2 capture and storage technologies will contribute between 10-55% of the global effort to reduce CO2 concentrations in the atmosphere by 2100. In this context, the Chemical-Looping Combustion is considered one of the better alternatives to reduce the cost of CO2 capture, especially when compared to conventional capture processes, since it does not require the separation of CO2 from N2, once fuel is not mixed directly with air or oxygen. This doctoral thesis is focused in the development of five manganese-based oxygen carriers, which were first characterized in order to determine which of them are most promising to be evaluated in CLC processes. The techniques and characterization methods used during the first stage were: mercury porosimetry, fracture resistance, X-ray diffraction (XRD), temperature programmed reduction and oxidation (TPR and TPO), oxygen transport capacity (Roc), chemical composition, redox by thermogravimetry and rate index. Completed these steps, it was found that the carriers Mn- ZrMF and ZrSG presented appropriate properties to be evaluated in a discontinuous fluidized bed reactor, where the experiment conditions are subject to the CLC conditions. After the testing reactor, the oxygen carriers were submitted to the following characterization techniques: DRX, TPR and SEM (Scanning Electron Microscopy). Mn-ZrMF carrier presented problems of agglomeration during testing in the reactor, being considered inappropriate for CLC. On the other side, the Mn-ZrSG carrier showed high reactivity with the fuels used (CO> H2> CH4). Due this Mn-ZrSG is appropriate for CO + H2 combustion, but suffer deactivation during CH4 combustion. Do not showed agglomeration problems. The attrition rate was low and the lifetime was than 11.000 hours. Thus this material can be considered suitable to be used in solid fuels CLC.

Made available in DSpace on 2014-12-17T15:42:00Z (GMT). No. of bitstreams: 1 Mariele ISM_DISSERT.pdf: 4704397 bytes, checksum: 9fa1538bc3d6948d492f9a6c378eaf62 (MD5) Previous issue date: 2012-07-20 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The oxidative desulfurization process (ODS) of a commercial diesel fuel was performed under mild conditions in the presence of catalysts based on vanadium or manganese, supported on alumina, clays (commercial, natural and pillared) and zeolites (NaX, NaY, beta, mordenite and ZSM-5). The catalysts were synthesized by wet impregnation and characterized by X-ray diffraction, textural analysis by N2 adsorption and scanning electron microscopy. The dibenzothiophene (DBT) was used as sulfur compound in catalytic evaluation. The reactions were performed using acetonitrile as solvent and the hydrogen peroxide as oxidant at 55?C. The reaction products were analized by gas chromatography (GC-FID). In the studied conditions, the process was efficient due to the DBT was converted to its corresponding sulfone. Both DBT and corresponding sulfone were extracted by the solvent. Removals and oxidations up to 100% of sulfur compound were achieved. The catalysts supported on ZSM-5 zeolite showed are more effective for oxidation reaction of sulfur compound, presenting the best results. It was observed for oxidation reaction, that vanadium catalysts were more effective and manganese catalysts showed best results for removal of sulfur compounds / O processo de Dessulfuriza??o Oxidativa (ODS) de um diesel comercial foi realizado em condi??es suaves na presen?a de catalisadores ? base de van?dio ou mangan?s, suportados em aluminas, argilas (comerciais, naturais e pilarizadas) e ze?litas (NaX, NaY, beta, mordenita, ZSM-5). Os catalisadores foram sintetizados via impregna??o ?mida e caracterizados por difra??o de raios-X, an?lise textural por adsor??o e dessor??o de nitrog?nio e microscopia eletr?nica de varredura. O dibenzotiofeno (DBT) foi utilizado como o composto de enxofre nos testes catal?ticos. As rea??es foram realizadas usando como solvente acetonitrila e como oxidante o per?xido de hidrog?nio a temperatura de 55?C. Os produtos de rea??o foram analisados por cromatografia gasosa (CG-FID). Nas condi??es estudadas o processo mostrouse eficiente, o DBT foi convertido para sua respectiva sulfona. Ambos DBT e a sulfona foram extra?dos pelo solvente. Remo??es e oxida??es de 100% do composto de enxofre foram alcan?adas. Os catalisadores suportados na ze?lita ZSM-5 mostraram-se mais efetivos para a rea??o de oxida??o do composto sulfurado, apresentando os melhores resultados. Observa-se para a rea??o de oxida??o que os catalisadores de van?dio foram mais efetivos, e os catalisadores de mangan?s apresentaram melhores resultados na extra??o dos compostos sulfurados

Made available in DSpace on 2014-12-17T14:07:17Z (GMT). No. of bitstreams: 1 OsvaldoCS_TESE.pdf: 5419870 bytes, checksum: 262730b1c0403826588e3ca7137507e0 (MD5) Previous issue date: 2013-07-19 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The production of waste from urban and industrial activities is one of the factors of environmental contamination and has aroused attention of the scientific community, in the sense of its reuse. On the other hand, the city of Salvador/Ba, with approximately 262 channels, responsible for storm water runoff, produces every year, by the intervention of cleaning and clearing channels, a significant volume of sediments (dredged mud), and thus an appropriate methodology for their final destination. This study aims to assess the influence of incorporation of these tailings in arrays of clay for production of interlocked block ceramic, also known as ceramic paver. All the raw materials from the metropolitan region of Salvador (RMS) were characterized by x-ray fluorescence, x-ray diffraction, thermal analysis (TG and TDA), particle size analysis and dilatometry. With the use of statistical experimental planning technique, ternary diagram was defined in the study region and the analyzed formulations. The specimens were prepared with dimensions of 60x20x5mm?, by uniaxial pressing of 30 MPa and after sintering at temperatures of 900?, 1000? and 1100?C the technological properties were evaluated: linear shrinkage, water absorption, apparent porosity, apparent specifies mass, flexural rupture and module. For the uniaxial compression strength used cylindrical probe body with ? 50 mm. The standard mass (MP) was prepared with 90% by weight of clay and 10% by weight of Channel sediment (SCP), not being verified significant variations in the properties of the final product. With the incorporation of 10% by weight of manganese residue (PFM) and 10% by weight of the Ceramic waste (RCB) in the mass default, in addition to adjusting the plasticity due to less waste clay content, provided increased linear firing shrinkage, due the significant concentration of K2O, forming liquid phase at low temperature, contributing to decreased porosity and mechanical resistance, being 92,5 MPa maximum compressive strength verified. After extract test leachate and soluble, the piece containing 10% of the PFM, was classified as non-hazardous and inert material according to NBR10004/04 ABNT. The results showed the feasibility on using waste, SCP, RCB and PFM clay mass, at temperatures above 900?C, paver ceramic production, according to the specifications of the technical standards, so that to exceed the 10% of the PFM, it becomes imperative to conduct studies of environmental impacts / A produ??o de res?duos provenientes das atividades urbanas e industriais ? um dos fatores de contamina??o ambiental e tem despertado aten??o da comunidade cientifica, no sentido do seu reaproveitamento. Por outro lado, a cidade do Salvador/Ba, com aproximadamente 262 canais, respons?veis pelo escoamento de ?guas pluviais, produz todo ano, pela necessidade de interven??o de limpeza e desobstru??o de canais, um volume significativo de sedimentos (lama dragada), impondo dessa forma uma metodologia adequada para sua destina??o final. Este trabalho tem como objetivo avaliar a influ?ncia da incorpora??o desses rejeitos em matrizes de argila para produ??o de bloco intertravado cer?mico, tamb?m conhecido como paver cer?mico. Todas as mat?rias primas oriundas da Regi?o Metropolitana de Salvador (RMS) foram caracterizadas por fluoresc?ncia de raios -X, difra??o de raios -X, analise t?rmica (TG e TDA), analise granulom?trica e dilatometria. Com a utiliza??o da t?cnica estat?stica de planejamento experimental, foi definida em diagrama tern?rio a regi?o de estudo e as formula??es analisadas. Foram preparados os corpos de prova com dimens?es de 60x20x5mm3, por prensagem uniaxial de 30 MPa e, ap?s sinteriza??o nas temperaturas de 900?, 1000? e 1100?C, as propriedades tecnol?gicas avaliadas foram: retra??o linear, absor??o de ?gua, porosidade aparente, massa especifica aparente, m?dulo de ruptura ? flex?o. Para a resist?ncia ? compress?o uniaxial utilizou-se o corpo de prova cil?ndrico com ? de 50mm. A massa padr?o (MP) foi preparada com 90% em peso de argila e 10% em peso do sedimento de canais (SCP), n?o sendo verificadas varia??es significativas nas propriedades do produto final. Com a incorpora??o de 10% em peso do res?duo de mangan?s (PFM) e 10% em peso do rejeito cer?mico (RCB) na massa padr?o, al?m do ajuste da plasticidade, em fun??o de menor teor de argilominerais dos res?duos, proporcionou aumento da retra??o linear de queima, devido a significativa concentra??o de K2O, formando fase liquida em baixa temperatura, contribuindo para diminui??o da porosidade e aumento da resist?ncia mec?nica, sendo 92,5 MPa a m?xima resist?ncia ? compress?o verificada. Ap?s teste do extrato lixiviado e solubilizado, a pe?a contendo 10% do PFM, foi classificada como material n?o perigoso e inerte segundo NBR10004/04 da ABNT. Os resultados mostraram viabilidade na utiliza??o dos res?duos SCP, RCB e PFM em massa argilosa, em temperaturas acima de 900?C, para produ??o de bloco intertravado, paver cer?mico, de acordo com as especifica??es das normas t?cnicas, de forma que, para teores superiores a 10% do PFM, torna-se imperativo a realiza??o de estudos de impactos ambientais

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-10T19:03:35Z No. of bitstreams: 1 BrunoFerreiraAmorim_TESE.pdf: 4546675 bytes, checksum: f3babdd1005205365d367583411ae46c (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-13T20:09:02Z (GMT) No. of bitstreams: 1 BrunoFerreiraAmorim_TESE.pdf: 4546675 bytes, checksum: f3babdd1005205365d367583411ae46c (MD5) / Made available in DSpace on 2016-06-13T20:09:02Z (GMT). No. of bitstreams: 1 BrunoFerreiraAmorim_TESE.pdf: 4546675 bytes, checksum: f3babdd1005205365d367583411ae46c (MD5) Previous issue date: 2015-12-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / As ferritas de cobalto-mangan?s (Co1?xMnxFe2O4 e Co1,2Fe1,8?xMnxO4) possuem uma estrutura do tipo espin?lio mista, e t?m sido consideradas como um das candidatas competitivas para grande variedade de aplica??es em dispositivos, desde a gera??o e detec??o de ultra-som, sensores, transformadores, bem como na ind?stria m?dica. Ferritas de cobaltomangan?s nanoestruturadas foram produzidas via moagem de alta energia, com subsequente tratamento t?rmico, e foram caracterizados por difra??o de raios X, fluoresc?ncia de raios X, microscopia eletr?nica de varredura e magnetiza??o. Amostras do tipo Co1?xMnxFe2O4 e Co1,2Fe1,8?xMnxO4 foram obtidas a partir dos p?s precursores Fe3O4, Co3O4 e Mn3O4, os quais foram estequiometricamente misturados e mo?dos por 10h e tratados termicamente ? 900?C por 2h. A difratometria confirma a forma??o das fases nanocristalinas puras para s?rie Co1,2Fe1,8?xMnxO4 com umdi?metro m?dio de cerca de 94nm. Verificou-se que o par?metro de rede aumenta com a substitui??o do Fe3? pelo Mn3?. A fluoresc?ncia de raios X revelou que as por??es de metais nas amostras estavam pr?xima das composi??es estequiom?tricas nominais. As caracter?sticas microestruturais observadas nas micrografias demonstraram que as part?culas formadas apresentam morfologia e granulometria bastante distintas. As medidas de histerese magn?ticas realizadas em baixa temperatura, mostraram que a magnetiza??o de satura??o e reman?ncia aumentaram com a concentra??o de mangan?s, enquanto que o campo coercivo diminuiu. A constante de anisotropia (Ke f ), foi calculada a partir dos ajustes dos dados pela lei de aproxima??o de satura??o. Verificou-se que a anisotropia diminui substancialmente com a substitui??o do ferro pelomangan?s. / The cobalt-manganese ferrites (Co1?xMnxFe2O4 and Co1,2Fe1,8?xMnxO4) has a mixed structure of spinel type and it has been regarded as one of candidates for petitive wide variety of applications in devices from ultrasonic generation and detection, sensors, transformers, as well as in medical industry. Ferrites cobalt-manganese nanostructured were produced via mechanical alloying with subsequent heat treatment and were characterized by X-ray diffraction, X-ray fluorescence, scanning electron microscopy and magnetization. Samples of Co1?xMnxFe2O4 and Co1,2Fe1,8?xMnxO4 were obtained from the precursor powders Fe3O4, Co3O4 and Mn3O4 which were stoichiometrically mixed and ground by 10h and heat treated at 900?C for 2h. The diffraction confirmed the formation of the pure nanocrystalline phases to series Co1,2Fe1,8?xMnxO4 with an average diameter of about 94nm. It was found that the lattice parameter increases with the substitution of Fe3? by Mn3?. The x-ray fluorescence revealed that the portions of metals in samples were close to the nominal stoichiometric compositions. The microstructural features observed in micrographs showed that the particles formed show very different morphology and particle size. The magnetic hysteresis measurements performed at low temperature showed that the saturation magnetization and remanence increased as the concentration of manganese, while the coercive field decreased. The anisotropy constant (Ke f ), was estimated from the data adjustments the law of approaching saturation. It was found that the anisotropy decreases substantially with the substitution of Fe by Mn.