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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.
101

The Hero at Rest

Tinsley, David 19 June 1995 (has links)
Predicting language outcomes in children who at age two are "late talkers" is a concern of Speech Language Pathologists. Currently, there is no conclusive data allowing specialists to predict which children will outgrow their delays and which children will not. The purpose of the present study is to analyze the effect of a receptive language delay on the outcome of the slow expressive language delayed child, and determine whether or not it is a viable predictor of poor outcomes. The subject information used in this project was compiled from the data collected and reported by Paul (1991) during the Portland Language Development Project (PLDP). Children in the PLDP first participated in the longitudinal study between the ages of twenty to thirtyfour months. They were categorized as being slow in expressive language development if they produced fewer that fifty intelligible words during this age range. They were then subgrouped into an expressive-receptive delayed group if they scored more than one standard deviation below the mean on the Reynell Developmental Language Scales. Of the twenty-five subjects with complete data over the five years of the study, nineteen were considered to be solely expressively delayed, while the remaining six were classified as having both an expressive and a receptive language delay. Lee's Developmental Sentence Scoring (DSS) (1974) was used to track the subject's expressive language abilities to the age of seven. DSS scores were analyzed yearly, using the Mann-Whitney nonparametric statistical test. This would determine whether the subjects considered to be both expressively and receptively delayed were exhibiting more difficulties in their expressive language abilities than those subjects with expressive delays alone. The results of the study indicated that significant differences did not exist between the two groups. Therefore, there was insufficient evidence to conclude that a receptive language delay at twenty to thirty-four months of age is a feasible predictor of lasting expressive language delays. This leads to the recommendation that additional research be conducted focusing on areas other than receptive language abilities as being predictors of poor expressive language outcomes.
102

Lokalproducerade livsmedel i Gävleborg : Köpmännens attityder

Karlsson, Malin January 2007 (has links)
<p>Syftet med studien är att undersöka vilken roll livsmedelsbutikerna har när det gäller att öka efterfrågan och konsumtionen av lokalproducerade livsmedel. Faktorer så som utbud, prissättning, variation samt marknadsföring och exponering har undersökts. Studien omfattar totalt 15 butiker i Gävle, Sandviken, Hofors, Ockelbo och Järvsö, och har varit en del av projektet,”Ditt val spelar roll –Konsumentens roll i den moderna livsmedelsproduktionen”, som är ett samarbete mellan Länsstyrelsen i Gävleborg och Högskolan i Gävle. Undersökningen har genomförts genom att enkäter har skickats ut till de 15 butikscheferna. Totalt returnerades 9 enkäter. Resultatet av studien visar att livsmedelsbutikerna spelar en betydande roll när det gäller att öka efterfrågan och konsumtionen av lokalproducerade livsmedel. Butikscheferna upplever dock att ett antal faktorer försvårar utökandet av det lokalproducerade sortimentet, till exempel centralstyrning, litet utbud av lokalproducerade livsmedel, höga inköpspriser samt relativt liten efterfrågan. Faktorer som skulle kunna leda till ett ökat lokalt sortiment är minskad centralstyrning och framtagande av en märkning, liknande den som används på ekologiska produkter.</p> / <p>The aim of the study is to examine which role the food shops have when it comes to increasing demand and consumption of local produced food. Factors as ranges, pricing, variation, marketing and exposure have been examined. The study covers totally 15 shops in Gävle, Sandviken, Hofors, Ockelbo och Järvsö and has been carried out as a part of the project.,”Ditt val spelar roll –Konsumentens roll i den moderna livsmedelsproduktionen”, that is a cooperation between the county administration in Gävleborg and the University of Gävle. The study was implemented through that each of the fifteen shop manager got a questionnaire. Nine questionnaires where returned. The result of the study shows that the food shops play a significant role when it comes to increasing demand and the consumption of local produced food. The shop managers experience however that a number of factors hamper the increase of the local produced assortment, for example central control, too small ranges of local produced food, high purchase pinches and relatively small demand. Factors that could evil to an increased local assortment are slimmed-down central control and developing of a labeling, similar the one used on ecological products.</p>
103

Lokalproducerade livsmedel i Gävleborg : Köpmännens attityder

Karlsson, Malin January 2007 (has links)
Syftet med studien är att undersöka vilken roll livsmedelsbutikerna har när det gäller att öka efterfrågan och konsumtionen av lokalproducerade livsmedel. Faktorer så som utbud, prissättning, variation samt marknadsföring och exponering har undersökts. Studien omfattar totalt 15 butiker i Gävle, Sandviken, Hofors, Ockelbo och Järvsö, och har varit en del av projektet,”Ditt val spelar roll –Konsumentens roll i den moderna livsmedelsproduktionen”, som är ett samarbete mellan Länsstyrelsen i Gävleborg och Högskolan i Gävle. Undersökningen har genomförts genom att enkäter har skickats ut till de 15 butikscheferna. Totalt returnerades 9 enkäter. Resultatet av studien visar att livsmedelsbutikerna spelar en betydande roll när det gäller att öka efterfrågan och konsumtionen av lokalproducerade livsmedel. Butikscheferna upplever dock att ett antal faktorer försvårar utökandet av det lokalproducerade sortimentet, till exempel centralstyrning, litet utbud av lokalproducerade livsmedel, höga inköpspriser samt relativt liten efterfrågan. Faktorer som skulle kunna leda till ett ökat lokalt sortiment är minskad centralstyrning och framtagande av en märkning, liknande den som används på ekologiska produkter. / The aim of the study is to examine which role the food shops have when it comes to increasing demand and consumption of local produced food. Factors as ranges, pricing, variation, marketing and exposure have been examined. The study covers totally 15 shops in Gävle, Sandviken, Hofors, Ockelbo och Järvsö and has been carried out as a part of the project.,”Ditt val spelar roll –Konsumentens roll i den moderna livsmedelsproduktionen”, that is a cooperation between the county administration in Gävleborg and the University of Gävle. The study was implemented through that each of the fifteen shop manager got a questionnaire. Nine questionnaires where returned. The result of the study shows that the food shops play a significant role when it comes to increasing demand and the consumption of local produced food. The shop managers experience however that a number of factors hamper the increase of the local produced assortment, for example central control, too small ranges of local produced food, high purchase pinches and relatively small demand. Factors that could evil to an increased local assortment are slimmed-down central control and developing of a labeling, similar the one used on ecological products.
104

Genotoxic and cytotoxic effects of contaminants discharged from the oil platforms in fish and mussels / Naftos platformų taršos genotoksinio ir citotoksinio poveikio įvertinimas žuvų ir moliuskų ląstelėse

Andreikėnaitė, Laura 02 November 2010 (has links)
Aquatic ecosystems are still being polluted with crude oil and other technogenic contaminants. In order to evaluate genotoxic and cytotoxic impact of this pollutants, micronucleus test and analysis of the other nuclear abnormalities is rather frequently being used. The main objective of the study is assessment of genotoxicity and cytotoxicity effects in different fish and bivalves exposed to the crude oil and other technogenic contaminants discharged from the several oil platforms (Statfjord B, Oseberg C, Minija). Environmental genotoxicity and cytotoxicity was evaluated by measuring the frequencies of micronuclei and other nuclear abnormalities in cells of mussels and fish caged in different oil platforms (Ekofisk, Statfjord B) field zones in situ. The study results provide new information about environmental geno-cytotoxicity in oil platforms field zones. The peculiarities of genotoxicity and cytotoxicity in fish and mussels after experimental treatment with crude oil from the North Sea oil platforms and Minija well in Lithuania and other technogenic contaminants (produced water, mixtures of PAHs, alkylphenols and heavy metals) were assessed. There were determined time-tissue-species-concentration-related relationships in induction of nuclear abnormalities in studied fish and mussels. The study results revealed usefulness of genotoxicity endpoints, as well as cytotoxicity endpoints for the evaluation of damage, caused by the contamination discharged from the marine oil... [to full text] / Į vandens ekosistemas patenka dideli kiekiai žaliavinės naftos bei naftos išgavimo technologinių procesų metu susidarančių teršalų. Šiame darbe analizuotas Šiaurės jūroje veikiančių naftos platformų (Statfjord B, Oseberg C), Barenco jūroje išgaunamos arktinės bei Lietuvoje esančio Minijos naftos gręžinio žaliavinės naftos, taip pat skirtingų gamybinių vandenų atskiedimų, įvairių poliaromatinių angliavandenilių ir alkilfenolių bei sunkiųjų metalų mišinių genotoksinis (pagal mikrobranduolių ir branduolio pumpurų dažnius) bei citotoksinis (pagal fragmentuotų-apoptozinių ir dvibranduolių ląstelių dažnius) poveikis skirtingų rūšių moliuskų ir žuvų ląstelėse. Taikant aktyvaus monitoringo metodą nustatytas Statfjord B ir Ekofisk naftos platformų aplinkos genotoksiškumas ir citotoksiškumas in situ. Šio darbo tyrimų rezultatai suteikė naujos informacijos apie naftos platformų aplinkos geno-citotoksiškumą, taip pat skirtingose platformose išgaunamos žaliavinės naftos, gamybinių vandenų, įvairių alkilfenolių, sunkiųjų metalų mišinių geno-citotoksinį poveikį vandens organizmams. Atlikti tyrimai leido įvertinti genotoksiškumo ir citotoksiškumo dėsningumus skirtingose organizmų grupėse ir jų audiniuose. Eksperimentų metu nustatyta skirtingų žaliavinės naftos, alkilfenolių, sunkiųjų metalų mišinių skirtingų koncentracijų, ekspozijos laiko bei geno-citotoksiškumo indukcijos priklausomybė. Darbe aprašyti metodai gali būti sėkmingai naudojami monitoringe kaip ankstyvieji biožymenys įvairių... [toliau žr. visą tekstą]
105

Naftos platformų taršos genotoksinio ir citotoksinio poveikio įvertinimas žuvų ir moliuskų ląstelėse / Genotoxic and cytotoxic effects of contaminants discharged from the oil platforms in fish and mussels

Andreikėnaitė, Laura 02 November 2010 (has links)
Į vandens ekosistemas patenka dideli kiekiai žaliavinės naftos bei naftos išgavimo technologinių procesų metu susidarančių teršalų. Šiame darbe analizuotas Šiaurės jūroje veikiančių naftos platformų (Statfjord B, Oseberg C), Barenco jūroje išgaunamos arktinės bei Lietuvoje esančio Minijos naftos gręžinio žaliavinės naftos, taip pat skirtingų gamybinių vandenų atskiedimų, įvairių poliaromatinių angliavandenilių ir alkilfenolių bei sunkiųjų metalų mišinių genotoksinis (pagal mikrobranduolių ir branduolio pumpurų dažnius) bei citotoksinis (pagal fragmentuotų-apoptozinių ir dvibranduolių ląstelių dažnius) poveikis skirtingų rūšių moliuskų ir žuvų ląstelėse. Taikant aktyvaus monitoringo metodą nustatytas Statfjord B ir Ekofisk naftos platformų aplinkos genotoksiškumas ir citotoksiškumas in situ. Šio darbo tyrimų rezultatai suteikė naujos informacijos apie naftos platformų aplinkos geno-citotoksiškumą, taip pat skirtingose platformose išgaunamos žaliavinės naftos, gamybinių vandenų, įvairių alkilfenolių, sunkiųjų metalų mišinių geno-citotoksinį poveikį vandens organizmams. Atlikti tyrimai leido įvertinti genotoksiškumo ir citotoksiškumo dėsningumus skirtingose organizmų grupėse ir jų audiniuose. Eksperimentų metu nustatyta skirtingų žaliavinės naftos, alkilfenolių, sunkiųjų metalų mišinių skirtingų koncentracijų, ekspozijos laiko bei geno-citotoksiškumo indukcijos priklausomybė. Darbe aprašyti metodai gali būti sėkmingai naudojami monitoringe kaip ankstyvieji biožymenys įvairių... [toliau žr. visą tekstą] / Aquatic ecosystems are still being polluted with crude oil and other technogenic contaminants. In order to evaluate genotoxic and cytotoxic impact of this pollutants, micronucleus test and analysis of the other nuclear abnormalities is rather frequently being used. The main objective of the study is assessment of genotoxicity and cytotoxicity effects in different fish and bivalves exposed to the crude oil and other technogenic contaminants discharged from the several oil platforms (Statfjord B, Oseberg C, Minija). Environmental genotoxicity and cytotoxicity was evaluated by measuring the frequencies of micronuclei and other nuclear abnormalities in cells of mussels and fish caged in different oil platforms (Ekofisk, Statfjord B) field zones in situ. The study results provide new information about environmental geno-cytotoxicity in oil platforms field zones. The peculiarities of genotoxicity and cytotoxicity in fish and mussels after experimental treatment with crude oil from the North Sea oil platforms and Minija well in Lithuania and other technogenic contaminants (produced water, mixtures of PAHs, alkylphenols and heavy metals) were assessed. There were determined time-tissue-species-concentration-related relationships in induction of nuclear abnormalities in studied fish and mussels. The study results revealed usefulness of genotoxicity endpoints, as well as cytotoxicity endpoints for the evaluation of damage, caused by the contamination discharged from the marine oil... [to full text]
106

Estudo teórico do processo de microfiltração em membranas cerâmicas.

SOUZA, Josedite Saraiva de. 13 September 2018 (has links)
Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-09-13T15:23:53Z No. of bitstreams: 1 JOSEDITE SARAIVA DE SOUZA - TESE (PPGEP) 2014.pdf: 5001055 bytes, checksum: b013c909ca0b39d1d6548d97afc484ce (MD5) / Made available in DSpace on 2018-09-13T15:23:53Z (GMT). No. of bitstreams: 1 JOSEDITE SARAIVA DE SOUZA - TESE (PPGEP) 2014.pdf: 5001055 bytes, checksum: b013c909ca0b39d1d6548d97afc484ce (MD5) Previous issue date: 2014-02-24 / Tecnologias inovadoras são necessárias para atender as normas de tratamento de águas produzidas cada vez mais rígidas, visto que a maioria dos processos de separação é limitada a partículas superiores a 10 m. Os processos de separação utilizando membranas cerâmicas veem despertando grande interesse da comunidade acadêmica e industrial. Mesmo assim, têm sido reportados poucos estudos, especialmente numéricos, referentes à aplicação de membranas inorgânicas na separação água/óleo. Nesse sentido, realizou-se um estudo da fluidodinâmica do escoamento de fluidos em tubos permeáveis (membrana cerâmica porosa tubular), em regime laminar. As equações de conservação de massa, momento linear e transporte de massa foram resolvidas com auxilio de uma malha estruturada usando o pacote comercial ANSYS CFX 12. A velocidade de permeação local foi determinada usando o modelo das resistências em série. A resistência específica da camada polarizada foi obtida pela equação de Carman-Kozeny. Os resultados numéricos foram comparados e avaliados utilizando-se de resultados analíticos e numéricos disponíveis na literatura apresentando boa concordância entre si. Os resultados numéricos indicam que, ao se utilizar o módulo de separação casco/membrana tubular proposto, há um favorecimento da transferência de massa e uma redução da espessura da camada limite polarizada. / Innovative technologies are needed to attend the requirements increasingly strict for produced waters treatment, whereas the most separation processes are limited to particles larger than 10 μm. Separation processes using ceramic membranes is attracting great interest from academic and industrial community. Nevertheless, it has been reported few studies, especially numerical, regarding the inorganic membranes application in the separation water/petroleum. Accordingly, a study of fluid-flow dynamics in porous tubes (tubular porous ceramic membrane) was performed, in a laminar regime. The mass, momentum and mass transport conservation equations were solved with the aid of a structured mesh using ANSYS commercial package CFX 12. The permeation velocity local was determined by using the resistance in series model. The specific resistance of the polarized layer was obtained by Carman-Kozeny equation. The numerical results were compared and evaluated using analytical and numerical results available in the literature presenting good agreement with each other. The numerical results indicate that, using the proposed separation module (shell / tube membrane), there is a mass transfer favoring and a reduction in the thickness boundary layer polarized.
107

Avaliação da resistência à compressão e da absorção de água de concretos utilizados após o tempo máximo de mistura e transporte especificado pela NBR 7212 / Evaluation of compressive strength and water absorption of concrete used after the maximum time of mixing and transport specified by NBR 7212

Polesello, Eduardo January 2012 (has links)
A norma brasileira NBR 7212 (ABNT, 1984), para execução de concreto dosado em central, estipula o tempo máximo para que o concreto seja descarregado (aplicado) completamente em 150 minutos. O tempo para utilização do concreto está vinculado às reações de hidratação do cimento e à perda de abatimento que ocorre com o concreto fresco, um fenômeno normal definido como sendo a perda de fluidez com o passar do tempo. Essa propriedade do concreto é particularmente importante no caso de concreto dosado em centrais, pelo fato do primeiro contato da água com o cimento ser na central enquanto que o lançamento/adensamento ocorrerá alguns minutos ou horas depois, quando o caminhão betoneira chegar ao canteiro de obras. Na prática, muitas vezes, ocorrem situações onde caminhões ficam carregados com concreto por 4 ou 5 horas, em função de atrasos no transporte ou na descarga, caracterizando um tempo bem acima do limite especificado pela norma. A dúvida de utilizar ou não o concreto nessas condições existe, pois não há conhecimento consolidado quanto às suas propriedades finais quando empregado com tempo de mistura que já tenham excedido o limite máximo especificado por norma. O objetivo desta pesquisa é investigar o comportamento de concretos do ponto de vista da resistência à compressão e absorção de água, quando utilizados com tempo de mistura de até 6 horas. Os concretos foram produzidos com dois tipos de cimento, CPIV e CPII, e o abatimento foi mantido ao longo das 6 horas em mistura com a incorporação de aditivo superplastificante à base policarboxilato. Nesse estudo adotaram-se três relações a/c e a produção dos concretos foi realizada em laboratório e em condição real numa central dosadora de concreto. As propriedades estudadas, resistência à compressão e absorção de água, foram analisadas aos 28 dias para vários tempos de mistura. O estudo mostrou que o tempo para utilização do concreto pode ser estendido acima do tempo especificado pela norma, sem que haja perda de sua resistência à compressão e alterações na absorção de água ao longo do tempo. / The Brazilian standard NBR 7212 (ABNT, 1984), for execution of ready-mixed concrete, specifies the maximum time for concrete to be discharged (used) completely in 150 minutes. The usage time of the concrete is due to reactions of the cement hydration and slump loss that occurs with fresh concrete, a normal phenomenon defined as the loss of fluidity along the time. This property of concrete is particularly important in the case of ready-mixed concrete plants, because the first contact of water with the cement is in the ready-mixed concrete plants while launching / densification occurs minutes or hours later, when the mixer truck arrives at the construction site. In fact, often, there are situations where trucks are loaded with concrete by 4 or 5 hours, due to delays in transportation or unloading, characterizing some time well above the limit specified by the standard. The question is to use or not use the concrete on these conditions, because there are no studies that confirm the final properties of the concrete when used with mixing time that have already exceeded the maximum limit specified by the standard. The aim of this study is to investigate the behavior of concrete from viewpoint of compressive strength and water absorption when used with mixing time up to 6 hours. The concretes were produced with two types of cement, CPIV and CPII, and slump was kept up to the six hours in a mixture with the incorporation of superplasticizer based polycarboxylate. In this study were adopted three relations w/c and the production of concrete was done in laboratory and real conditions in a ready-mixed concrete plants. The studied properties, compressive strength and water absorption were analyzed in 28 days for several mixing times. The study showed that the time of use from the concrete can be extended over the time specified by the standard, without loss of compressive strength and changes in the water absorption over time.
108

Remo??o conjugada de metais e ?leo de ?gua produzida

Nunes, Shirlle Katia da Silva 06 March 2009 (has links)
Made available in DSpace on 2014-12-17T15:01:19Z (GMT). No. of bitstreams: 1 ShirlleKSN.pdf: 1257251 bytes, checksum: 8e3d9e5d34873e918e7ada174b5ca7e3 (MD5) Previous issue date: 2009-03-06 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Petroleum can be associated or not with natural gas, but in both cases water is always present in its formation. The presence of water causes several problems, such as the difficulty of removing the petroleum from the reservoir rock and the formation of waterin-oil and oil-in-water emulsions. The produced water causes environmental problems, which should be solved to reduce the effect of petroleum industry in the environment. The main objective of this work is to remove simultaneously from the produced water the dispersed petroleum and dissolved metals. The process is made possible through the use of anionic surfactants that with its hydrophilic heads interacts with ionized metals and with its lipophilic tails interacts with the oil. The studied metals were: calcium, magnesium, barium, and cadmium. The surfactants used in this research were derived from: soy oil, sunflower oil, coconut oil, and a soap obtained from a mixture of 5wt.% coconut oil and 95wt.% animal fat. It was used a sample of produced water from Terminal de S?o Sebasti?o, S?o Paulo. As the concentration of the studied metals in produced water presented values close to 300 mg/L, it was decided to use this concentration as reference for the development of this research. Molecular absorption and atomic absorption spectroscopy were used to determine petroleum and metals concentrations in the water sample, respectively. A constant pressure filtration system was used to promote the separation of solid and liquid phases. To represent the behavior of the studied systems it was developed an equilibrium model and a mathematical one. The obtained results showed that all used surfactants presented similar behavior with relation to metals extraction, being selected the surfactant derived from soy oil for this purpose. The values of the partition coefficients between the solid and liquid phases " D " for the studied metals varied from 0.2 to 1.1, while the coefficients for equilibrium model " K " varied from 0.0002 and 0.0009. The removal percentile for oil with all metals associated was near 100%, showing the efficiency of the process / O petr?leo pode estar associado ou n?o com o g?s natural, mas, em ambos os casos, a ?gua est? presente desde a sua forma??o. A presen?a da ?gua ocasiona diversos problemas, tais como a dificuldade de remover o petr?leo da rocha e a forma??o de emuls?es do tipo ?gua-em-?leo e ?leo-em-?gua. A ?gua de produ??o gera problemas ambientais, que devem ser solucionados para que o efeito da ind?stria do petr?leo no meio ambiente seja minimizado. Este trabalho tem por objetivo remover associadamente o petr?leo disperso e os metais dissolvidos na ?gua de produ??o. O processo ? viabilizado atrav?s da utiliza??o de tensoativos ani?nicos, que com suas partes hidrof?licas interagem com os metais ionizados e com suas partes lipof?licas interagem com o ?leo. Os metais estudados foram: o c?lcio, o magn?sio, o b?rio e o c?dmio. Os tensoativos utilizados na pesquisa foram derivados dos ?leos de soja, girassol, coco e um sab?o oriundo de uma mistura de 5% do ?leo de coco e 95% de gordura animal. Utilizou-se uma amostra de ?gua produzida proveniente do Terminal de S?o Sebasti?o, em S?o Paulo. Como a concentra??o dos metais estudados nesta ?gua apresentavam valores pr?ximos a 300 mg/L, decidiu-se fixar esta concentra??o como refer?ncia para o desenvolvimento da pesquisa. Para determinar as concentra??es dos metais e do petr?leo na ?gua foram utilizados os espectrofot?metros de absor??o at?mica e de absor??o molecular, respectivamente. Utilizou-se um sistema de filtra??o a press?o constante para promover a separa??o das fases s?lida e l?quida. Para representar o comportamento dos sistemas em estudo desenvolveu-se um modelo de equil?brio e outro matem?tico. Os resultados mostraram que todos os tensoativos desenvolvidos apresentavam comportamento similar com rela??o ? extra??o dos metais, sendo selecionado o tensoativo derivado do ?leo de soja para este prop?sito. Os valores dos coeficientes de parti??o dos metais entre as fases s?lida e l?quida D variaram de 0,2 a 1,1, enquanto que os dos coeficientes do modelo de equil?brio K ficaram entre 0,0002 e 0,0009. O percentual de remo??o conjugada do ?leo com todos os metais foi praticamente igual a 100 %, o que comprovou a efici?ncia do processo
109

Modelagem da transfer?ncia de massa na remo??o do ?leo da ?gua produzida por flota??o em coluna com uso de tensoativos de origem vegetal

Valen?a, Raniere Dantas 10 February 2012 (has links)
Made available in DSpace on 2014-12-17T15:01:28Z (GMT). No. of bitstreams: 1 RaniereDV_DISSERT.pdf: 2210959 bytes, checksum: 50b0d022488541db247d404d8e3dc596 (MD5) Previous issue date: 2012-02-10 / The treatment of oil produced water and its implications are continually under investigation and several questions are related to this subject. In the Northeast Region Brazil, the onshore reservoirs are, in its majority, mature oil fields with high production of water. As this oil produced water has high levels of oil, it cannot be directly discarded into the environment because it represents a risk for contamination of soil, water, and groundwater, or even may cause harm to living bodies. Currently, polyelectrolytes that promote the coalescence of the oil droplets are used to remove the dispersed oil phase, enhancing the effectiveness of the flotation process. The non-biodegradability and high cost of polyelectrolytes are limiting factors for its application. On this context, it is necessary to develop studies for the search of more environmentally friendly products to apply in the flotation process. In this work it is proposed the modeling of the flotation process, in a glass column, using surfactants derived from vegetal oils to replace the polyelectrolytes, as well as to obtain a model that represents the experimental data. In addition, it was made a comparative study between the models described in the literature and the one developed in this research. The obtained results showed that the developed model presented high correlation coefficients when fitting the experimental data (R2 > 0.98), thus proving its efficiency in modeling the experimental data. / O tratamento da ?gua produzida (AP) e suas implica??es s?o continuamente estudadas e v?rias perguntas s?o direcionadas a esta ?rea. No Nordeste do Brasil os reservat?rios em terra (ONSHORE) s?o, em sua maioria, po?os maduros, com alta produ??o de ?gua, e como esta ?gua possui altos teores de ?leo, n?o pode ser descartada simplesmente, pois s?o um risco para o ambiente pela contamina??o do solo, ?guas subterr?neas ou mesmo animais e plantas. Atualmente, s?o utilizados polieletr?litos que facilitam a coalesc?ncia das gotas de ?leo dispersas nesta ?gua para assim aumentar a efici?ncia do seu processo de tratamento que ? a flota??o. Estes polieletr?litos al?m de serem de alto custo n?o s?o biodegrad?veis o que limita sua aplica??o. Diante deste contexto, surge a necessidade de estudar produtos menos agressivos ao meio ambiente que viabilizem este tratamento. Este trabalho prop?s a modelagem do processo de flota??o em coluna utilizando tensoativos de origem vegetal em substitui??o aos polieletr?litos, bem como obter uma correla??o que represente os dados experimentais. Al?m disto, foi realizado um estudo comparativo entre modelos apresentados na literatura e o desenvolvido neste trabalho. Os resultados mostraram que o modelo desenvolvido obteve coeficientes de correla??o R2, em rela??o aos dados experimentais, acima de 0,98, comprovando sua efici?ncia na modelagem dos dados experimentais.
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Integra??o dos processos de flota??o e foto-fenton para redu??o de ?leos e graxas de ?gua produzida em campos de petr?leo

Silva, Syllos Santos da 01 July 2013 (has links)
Made available in DSpace on 2014-12-17T15:01:56Z (GMT). No. of bitstreams: 1 SyllosSS_TESE.pdf: 2557262 bytes, checksum: 77d0a0faa8e481b116f80dda9a4c8e96 (MD5) Previous issue date: 2013-07-01 / During production of oil and gas, there is also the production of an aqueous effluent called produced water. This byproduct has in its composition salts, organic compounds, gases and heavy metals. This research aimed to evaluate the integration of processes Induced Air Flotation (IAF) and photo-Fenton for reducing the Total Oils and Greases (TOG) present in produced water. Experiments were performed with synthetic wastewater prepared from the dispersion of crude oil in saline solution. The system was stirred for 25 min at 33,000 rpm and then allowed to stand for 50 min to allow free oil separation. The initial oil concentration in synthetic wastewater was 300 ppm and 35 ppm for the flotation and the photo-Fenton steps, respectively. These values of initial oil concentration were established based on average values of primary processing units in Potiguar Basin. The processes were studied individually and then the integration was performed considering the best experimental conditions found in each individual step. The separation by flotation showed high removal rate of oil with first-order kinetic behavior. The flotation kinetics was dependent on both the concentration and the hydrophilic-lipophilic balance (HLB) of the surfactant. The best result was obtained for the concentration of 4.06.10-3 mM (k = 0.7719 min-1) of surfactant EO 2, which represents 86% of reduction in TOG after 4 min. For series of surfactants evaluated, the separation efficiency was found to be improved by the use of surfactants with low HLB. Regarding the TOG reduction step by photo-Fenton, the largest oil removal reached was 84% after 45 min of reaction, using 0.44 mM and 10 mM of ferrous ions and hydrogen peroxide, respectively. The best experimental conditions encountered in the integrated process was 10 min of flotation followed by 45 min of photo-Fenton with overall TOG reduction of 99%, which represents 5 ppm of TOG in the treated effluent. The integration of processes flotation and photo-Fenton proved to be highly effective in reducing TOG of produced water in oilfields / Durante a produ??o de ?leo e g?s, ocorre tamb?m ? produ??o de uma corrente aquosa denominada ?gua de produ??o de petr?leo. Este subproduto apresenta em sua composi??o sais, compostos org?nicos, gases e metais pesados. Esta pesquisa buscou avaliar a integra??o dos processos de Flota??o por Ar Induzido (FAI) e foto-Fenton para a redu??o do Teor de ?leos e Graxas (TOG) presente em ?guas produzidas, visando recuperar ?leo presente na fase aquosa e mineralizar a carga org?nica remanescente. Os experimentos foram realizados com efluente sint?tico preparado a partir da dispers?o de petr?leo bruto em solu??o salina. O sistema foi agitado por 25 min a 33.000 rpm e depois deixado em repouso por 50 min para permitir a separa??o do ?leo livre. A concentra??o inicial de ?leo (TOG) no efluente sint?tico foi de 300 ppm e 35 ppm para as etapas de flota??o e de foto-Fenton, respectivamente. Estes valores iniciais de concentra??o de ?leo foram estabelecidos tomando com base a TOG m?dio do efluente nas unidades de processamento prim?rio da bacia Potiguar. Os processos foram estudados individualmente e, em seguida, realizada a integra??o considerando as melhores condi??es experimentais encontrada em cada etapa individualmente. A separa??o por flota??o apresentou elevada taxa de remo??o de ?leo com comportamento cin?tico de primeira ordem. A cin?tica de flota??o foi dependente tanto da concentra??o quanto do Balan?o Hidrof?lico-Lipof?lico (BHL) do tensoativo. O melhor resultado foi obtido para a concentra??o de 4,06.10-3 mM (k = 0,7719 min-1) do tensoativo EO 2, o que representa 86 % de redu??o do TOG ap?s 4 min de flota??o. Para a s?rie de tensoativos estudada, a efici?ncia de separa??o mostrou-se melhorada com o uso de tensoativo com menores BHL. Com respeito ? etapa de redu??o do TOG por foto-Fenton, a maior remo??o de ?leo alcan?ada foi de 84% ap?s 45 min de rea??o, utilizando 0,44 mM e 10 mM de ?ons ferrosos e per?xido de hidrog?nio, respectivamente. As melhores condi??es experimentais encontradas para os processos integrados foram 10 min de flota??o seguida de 45 min de foto-Fenton, com redu??o global de TOG de 99%, o que representa 5 ppm de TOG no efluente tratado. A integra??o dos processos flota??o e foto-Fenton mostrou ser altamente eficiente na redu??o de TOG em ?guas produzidas em campos de petr?leo

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