Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-27T13:30:35Z No. of bitstreams: 5 45.pdf: 345535 bytes, checksum: c3649a3cfc01189e92c6e9258cbcfc4a (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-27T18:12:58Z (GMT) No. of bitstreams: 5 45.pdf: 345535 bytes, checksum: c3649a3cfc01189e92c6e9258cbcfc4a (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) / Made available in DSpace on 2015-02-27T18:12:58Z (GMT). No. of bitstreams: 5 45.pdf: 345535 bytes, checksum: c3649a3cfc01189e92c6e9258cbcfc4a (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) Previous issue date: 2013 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes) / O Brasil possui imensas ?reas de pastagens e a esp?cie mais cultivada ? a Brachiaria brizantha. O controle das plantas daninhas nestas ?reas ? realizado predominantemente pelo uso de herbicidas com longo per?odo residual, destacando-se o picloram. Este ? utilizado no controle de plantas daninhas de folhas largas perenes e tem sido intensamente pesquisado em fun??o da alta meia vida nos solos, sendo sua persist?ncia dependente do clima e atributos ed?ficos, como textura e pH. Objetivou-se com este trabalho avaliar o desenvolvimento e o potencial remediador de B. brizantha em solo contaminado com picloram em diferentes n?veis de pH. O delineamento experimental utilizado foi em blocos casualizados, com quatro repeti??es e com faixa de pH variando entre 4,5 e 5,6. Cultivou-se a forrageira at? a flora??o, quando se determinou a massa da mat?ria seca dos componentes da planta e posteriormente, cultivou-se plantas de pepino como indicadores da presen?a do herbicida. O picloram causou redu??o no ac?mulo da massa da mat?ria seca total das plantas de B. brizantha, em consequ?ncia do efeito negativo sobre a produ??o de ra?zes, independente do pH do solo. Nas folhas o herbicida promoveu redu??o na massa da mat?ria seca em solo com maior pH. Nos tratamentos com maior valor de pH, na profundidade de 35 cm, constatou-se maior ac?mulo de massa da mat?ria seca de ra?zes quando n?o se aplicou o herbicida, indicando que em solos menos ?cidos o herbicida tende a prejudicar o desenvolvimento de ra?zes da forrageira em maiores profundidades. A B. brizantha reduziu a concentra??o de picloram na camada superficial de solo, o que pode ser atribu?do a sua capacidade de degradar o herbicida e tamb?m ao fato desta absorver e exsudar o herbicida ao longo das camadas de solo. Observou-se tamb?m que em solos com maiores valores de pH o herbicida tem maior potencial de lixivia??o, principalmente quando n?o cultivado com B. brizantha. Solos com menores valores de pH tendem ? maior sor??o do herbicida, e consequentemente, a maior concentra??o do mesmo em camadas intermedi?rias. Pode-se concluir que altas concentra??es de picloram no solo s?o nocivas ao crescimento da B. brizantha, principalmente sob condi??es de solos menos ?cidos e esta forrageira pode ser usada para remedia??o de solos contaminados por picloram e na preven??o de sua lixivia??o, que ? maior em solos tratados com calc?rio. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2013. / ABSTRACT Brazil has vast areas of pasture and the specie most widely cultivated is Brachiaria brizantha. The weed control in these areas is carried out predominantly using herbicides of long residual period, highlighting the picloram. This herbicide is used for weed control broadleaf evergreen and has been intensively investigated due to the high half-life in soil, and their persistence dependent on climate and soil attributes such as texture and pH. The aim of this work was to evaluate the development and potential remediation of B. brizantha in soil contaminated with picloram at different pH levels. The experimental design was a randomized block with four replications and pH among 4.5 and 5.6. The forage was grown up to flowering, when determined the dry weight of the plant components and subsequently were cultivated cucumber plants such as bioindicators of presence of the herbicide. The picloram caused reduction of total dry matter accumulation of B. brizantha, consequently to negative effect on root production, regardless soil pH. The herbicide caused a reduction of leaf dry matter on plants cultivated in higher soil pH. In treatments of high pH value at a depth of 35 cm, there was greater accumulation of dry matter of roots when the herbicide was not applied, indicating that in less acid soils the herbicide tends to hinder the development of grass root at greater depths. B. brizantha reduced picloram concentration in the soil shallow layer, which can be attributed to its ability of degrade the herbicide, and also by fact of absorption and exudation herbicide along the soil layers. In higher pH soils also observed that ??the herbicide has higher potential for leaching, mainly when not cultivated B. brizantha. Soils with lower pH values ??tend to greater sorption of the herbicide, and consequently, a higher concentration of the same in the intermediate layers. Concluded that high concentrations of picloram in the soil are harmful to the growth of B. brizantha, mainly under conditions of soils less acidic and this forage can be used for remediation of soils contaminated by picloram and preventing leaching, which is greater in soils treated with lime.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-08-01T14:05:21Z No. of bitstreams: 1 AllanMartinsNeves_DISSERT.pdf: 2153659 bytes, checksum: 19b8e265b34574f2712c75f067e65296 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-08-07T15:28:10Z (GMT) No. of bitstreams: 1 AllanMartinsNeves_DISSERT.pdf: 2153659 bytes, checksum: 19b8e265b34574f2712c75f067e65296 (MD5) / Made available in DSpace on 2017-08-07T15:28:10Z (GMT). No. of bitstreams: 1 AllanMartinsNeves_DISSERT.pdf: 2153659 bytes, checksum: 19b8e265b34574f2712c75f067e65296 (MD5) Previous issue date: 2017-06-28 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / O cen?rio atual da ind?stria do petr?leo envolve explorar e produzir reservas com desafios t?cnicos enormes. Desta forma, torna-se cada vez mais necess?rio o conhecimento dos mecanismos que impactam a produ??o do ?leo. Um exemplo disso s?o as novas descobertas no mar brasileiro, como o pr?-sal, composto por grandes acumula??es de ?leo leve, com alto valor comercial. Um fator determinante a ser considerado ? o tipo de rocha reservat?rio predominante na forma??o destas reservas, que s?o rochas carbon?ticas, principalmente o calc?rio, que em sua maioria apresenta molhabilidade favor?vel ao ?leo, fator que diminui a recupera??o do petr?leo. Assim, estudos v?m sendo desenvolvidos com esse tipo de rocha visando inverter sua molhabilidade e melhorar a produtividade. Uma maneira de melhorar essas condi??es no reservat?rio ? atrav?s dos m?todos qu?micos envolvendo tensoativos, que pela sua natureza anfif?lica, t?m a capacidade de se adsorver em interfaces e superf?cies de acordo com sua afinidade, diminuindo a energia livre interfacial, podendo inverter a molhabilidade da rocha, facilitando o fluxo de ?leo e assim, melhorando sua recupera??o. O objetivo desse trabalho foi estudar como diferentes tipos de tensoativos se adsorvem na rocha calc?ria, e se eram capazes de alterar sua molhabilidade. Para isso, foi utilizado o m?todo de banho finito para tr?s tensoativos: OCS (ani?nico), C16TAB (cati?nico) e ULTRANEX 110 (n?o i?nico), variando-se par?metros como a temperatura, a massa de adsorverte (calc?rio), tempo de contato e concentra??o de tensoativo. Tamb?m foram feitas an?lises de ?ngulo de contato para analisar a molhabilidade e de potencial zeta. O OCS foi o ?nico tensoativo que apresentou adsor??o significativa na rocha, possivelmente por apresentar ?ons opostamente carregados aos da rocha. O aumento da temperatura de 30?C para 50?C ocasionou decr?scimo na capacidade de adsor??o. O calc?rio in natura apresentou molhabilidade mista, com forte afinidade ao ?leo, que ap?s tratamento ocorreu diminui??o da molhabilidade ao ?leo, no entanto tamb?m diminuiu em rela??o ? ?gua. As medidas de potencial zeta mostraram que as atra??es eletrost?ticas desempenharam papel importante na adsor??o, obtendo-se maior valor em m?dulo para o OCS. / The current scenario of the oil industry involves exploring and producing reserves with big technical challenges, in this way, it becomes increasingly necessary to know the mechanisms that impact the oil production. An example of this is the new discoveries in the Brazilian sea, with the pre-salt, composed of large accumulations of high commercial value light oil. However, a determining factor to be considered is the type of reservoir rock predominant in the formation of its reserves. These rocks are composed almost of carbonates of calcium that form the carbonate rocks, mainly limestone, which in the majority of them are oil-wet, a factor that Decreases the recovery of oil. Thus, studies have been developed in this type of rock in order to reverse its wettability and improve productivity. One way of change the wettability of the reservoir is through the chemical methods involving surfactants, which by their amphiphilic nature have the ability to adsorb at interfaces and surfaces according to their affinity, reducing the free interfacial energy, which can reverse the wettability of the rock, facilitating the flow of oil and thus, improving its recovery. The objective of this work was to study how different types of surfactants adsorb in limestone, and if they were able to alter their wettability. For this, the finite bath method was used for three surfactants: OCS (anionic), C16TAB (cationic) and ULTRANEX 110 (nonionic), varying parameters such as temperature, adsorption mass (limestone), contact time and concentration of surfactant. Contact angle analysis was also performed to analyze wettability and zeta potential. OCS was the only surfactant that presented significant adsorption in the rock, possibly due to the presence of electrically charged ions. The increase in temperature from 30 ? C to 50 ? C caused a decrease in the adsorption capacity. The limestone in natura presented mixed wettability, with strong affinity to the oil, after treatment the wettability decreased to oil, however it also decreased in relation to water. The measurements of zeta potential showed that the eletrostatic attractions played an important role in the adsorption, obtaining greater value in the module for the OCS.

Submitted by Jadson Francisco de Jesus SILVA (jadson@uefs.br) on 2018-01-30T22:07:52Z No. of bitstreams: 1 Uiliana M?rcia da Silva Merc?s Farias_2017.pdf: 5844655 bytes, checksum: 1df6b86cb5dfd9f89a7bbd299fa1bf93 (MD5) / Made available in DSpace on 2018-01-30T22:07:52Z (GMT). No. of bitstreams: 1 Uiliana M?rcia da Silva Merc?s Farias_2017.pdf: 5844655 bytes, checksum: 1df6b86cb5dfd9f89a7bbd299fa1bf93 (MD5) Previous issue date: 2017-03-20 / The use of waste from Dimension Stone Industry as an inert material can be a good way to promote the sustainability of the construction sector. The Cariri stone is one of the dimension stones explored in state of Ceara, in Brazil. Thus, this work was developed with the main goal of studying a self-compacting concrete production (SCC) using Cariri stone sawdust waste (CSSW) in partial replacement with the natural fine aggregate. The SCC was designed using the method proposed by Melo (2005) considering two w/c ratios (0.57-0.70), and 10% of CSSW. The study was carried out in three stages: material characterization, mortar phase evaluation and SCC phase evaluation. In the fresh state, SCC was evaluated for fluidity, plastic viscosity, blocking capacity and segregation resistance, using V funnel, J-Ring, L-box and segregation column. In the hardened state, the SCC was evaluated for axial compressive strength, splitting tensile strength and water absorption, void index and specific density. The results showed that CSSW improve SCC cohesiveness and homogeneity, and it is feasible to apply up to 10% of CSSW in SCC production. / No sentido de promover a sustentabilidade do setor da constru??o civil, procura-se alternativas para diminuir o impacto ambiental gerado, atrav?s da descoberta de novos materiais alternativos, como os res?duos da ind?stria de beneficiamento de rochas ornamentais. Dentre os tipos de rochas ornamentais exploradas no Brasil, destaca-se um calc?rio laminado conhecido como ?Pedra Cariri?, que ? explorado no estado do Cear?. Assim, esse trabalho foi desenvolvido com o objetivo de estudar a produ??o de concreto autoadens?vel (CAA) utilizando res?duos de serragem de pedra Cariri (RSPC) em substitui??o parcial ao agregado mi?do natural. Utilizando a metodologia de Melo (2005) para produ??o de CAA, foram definidas as rela??es a/c (0,57-0,70). O estudo se deu em tr?s etapas: caracteriza??o dos materiais, fase argamassa e fase CAA. No estado fresco, o CAA foi avaliado quanto ? fluidez, viscosidade pl?stica, habilidade passante e resist?ncia ? segrega??o, por meio do ensaio de espalhamento, funil V, Anel J, Caixa L e coluna de segrega??o. No estado endurecido, o CAA foi avaliado quanto ? resist?ncia ? compress?o axial, ? resist?ncia ? tra??o por compress?o diametral e ? absor??o de ?gua, ?ndice de vazios e massa espec?fica. Os resultados indicaram a possibilidade da aplica??o de at? 10% de RSPC na produ??o de CAA.

Made available in DSpace on 2014-12-17T14:06:46Z (GMT). No. of bitstreams: 1 RobertoALS.pdf: 742174 bytes, checksum: d1b0bdbe4af3f236ae47837eb186d487 (MD5) Previous issue date: 2008-03-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / There are ores of clay in Piau? State that are used for red structural ceramics, which are naturally contaminated with calcareous vein. This is one thing that impedes its exploration in an adequate way, especially for tile production. The present work aims at verifying the influence of the calcareous contents in the technological structural ceramics area, seeking to determine a maximum permissible calcareous proportion/contents in the ceramic mass using the patterns of the local industry production. For the consecution of this paper, it was characterized the clay and calcareous material by FRX, DRX, TGA and DTA. It was also configurated by extrusion and burnt in the temperatures of 850?C, 900?C, 950?C and 1000?C pieces of the corpus with 0, 5, 10, 15 e 20% of calcareous proportion. After that, it was carried out technological samples of linear retraction, water absortion, apparent porosity, specific apparent mass and mechanic resistance. The results showed the possibility of using calcareous in the ceramic mass and in some cases the technological properties got better / O estado do Piau? tem jazidas de argilas utilizadas para cer?mica vermelha estrutural, que naturalmente est?o contaminadas com veios de calc?rio, o que impede a sua explora??o de forma adequada, principalmente para a produ??o de telhas. O presente trabalho tem o objetivo de verificar a influ?ncia do teor de calc?rio nas propriedades tecnol?gicas da cer?mica estrutural, visando definir um teor m?ximo de calc?rio admiss?vel na massa cer?mica utilizando-se dos padr?es de produ??o da ind?stria local. Para isso, foram caracterizadas as mat?rias-primas argila e calc?rio por FRX, DRX, TGA e DTA. Tamb?m foram conformados por extrus?o e queimados nas temperaturas de 850?C, 900?C, 950?C e 1000?C corpos-de-prova com 0%, 5%, 10%, 15% e 20% de teor de calc?rio, em seguida, realizados ensaios tecnol?gicos de retra??o linear, absor??o de ?gua, porosidade aparente, massa espec?fica aparente e resist?ncia mec?nica ? flex?o. Os resultados mostraram a possibilidade de se utilizar calc?rio na massa cer?mica, sendo que em alguns casos melhorou as propriedades tecnol?gicas

Made available in DSpace on 2014-12-17T15:42:08Z (GMT). No. of bitstreams: 1 GilianeCMNS_DISSERT.pdf: 1750841 bytes, checksum: cedbb003a4fc658825db6f8e66611748 (MD5) Previous issue date: 2013-06-25 / In this research the removal of light and heavy oil from disintegrated limestone was investigated with use of microemulsions. These chemical systems were composed by surfactant, cosurfactant, oil phase and aqueous phase. In the studied systems, three points in the water -rich microemulsion region of the phase diagrams were used in oil removal experiments. These microemulsion systems were characterized to evaluate the influence of particle size, surface tension, density and viscosity in micellar stability and to understand how the physical properties can influence the oil recovery process. The limestone rock sample was characterized by thermogravimetry, BET area, scanning electron microscopy and X-ray fluorescence. After preparation, the rock was placed in contact with light and heavy oil solutions to allow oil adsorption. The removal tests were performed to evaluate the influence of contact time (1 minute, 30 minutes, 60 minutes and 120 minutes), the concentration of active matter (20, 30 and 40 %), different cosurfactants and different oil phases. For the heavy oil, the best result was on SME 1, with 20 % of active matter, 1 minute of contact time, with efficiency of 93,33 %. For the light oil, also the SME 1, with 20 % of active matter, 120 minutes of contact time, with 62,38 % of efficiency. From the obtained results, it was possible to conclude that microemulsions can be considered as efficient chemical systems for oil removal from limestone formations / O presente trabalho objetivou estudar a remo??o de fra??es de ?leo leve e pesado em rocha calc?ria desintegrada atrav?s de sistemas microemulsionados, comparando as efici?ncias de remo??o em diferentes concentra??es de mat?ria ativa (C/T) e tempo de contato. Os sistemas microemulsionados (SME) s?o constitu?dos por tensoativo, cotensoativo, fase oleosa e fase aquosa. Nos sistemas estudados, tr?s pontos ricos em ?gua da regi?o de microemuls?o foram utilizados para verificar a efici?ncia de remo??o. Os sistemas foram caracterizados para avaliar a influ?ncia do tamanho do agregado, tens?o superficial e viscosidade na estabilidade micelar e compreender como as propriedades f?sicas podem influenciar o processo de remo??o de ?leo. A amostra de rocha calc?ria foi caracterizada por Termogravimetria, ?rea BET, Microscopia Eletr?nica de Varredura, Difra??o de Raios-X e Fluoresc?ncia de Raios-X. A rocha preparada foi colocada em contato com solu??o de ?leo leve e pesado em xileno para permitir a adsor??o de ?leo. Os testes de remo??o foram realizados a fim de avaliar a influ?ncia do tempo de contato (1, 30, 60 e 120 minutos), da concentra??o de mat?ria ativa (20, 30 e 40%), do cotensoativo e da fase oleosa. Para o ?leo pesado, o melhor resultado foi para o SME 1, com 20 % de mat?ria ativa, no tempo de 1 minuto, com 93,33 % de efici?ncia. Para o ?leo leve, o SME 1 no percentual de 20 %, com 120 minutos apresentou o melhor rendimento, com 62,38 %. A partir dos resultados obtidos, concluiu-se que os sistemas microemulsionados apresentam-se como uma alternativa eficaz para remo??o de ?leo em forma??es calc?rias