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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.
41

Dinâmica da água e dos nutrientes no sistema de produção integrado gerado pela dessalinização da água de poço do semiárido brasileiro / Dynamics of water and nutrients in the integrated production system generated by desalination of ground water from Brazilian semiarid

Eduardo Ballespi de Castro Vasconcellos 01 July 2011 (has links)
Foram realizadas análises isotópicas, físicas e químicas na água, no solo e nas plantas do Sistema de Produção Integrado Utilizando Efluentes de Dessalinização, criado pela Embrapa Semiárido, como uma alternativa para a reutilização desses efluentes na produção de alimentos e diminuição do impacto ambiental causado pelo descarte incorreto deste rejeito. O sistema avaliado se localiza no Campo Experimental da Caatinga, na Embrapa Semiárido (Petrolina-PE). Os resultados encontrados quanto à ciclagem dos nutrientes indicaram a ocorrência de uma contínua adição dos cátions Ca+2, Mg+2 , K+ e Na+ no solo durante o experimento, de 199 kg ha-1, 88 kg ha-1, 51 kg ha-1 e 142 kg ha-1, respectivamente. A eficiência de retirada do Ca+2, Mg+2 e Na+ pela Atriplex nummularia foi de 12,1, 4,3 e 23,9%, respectivamente; Ocorreu uma elevada perda de nitrogênio no sistema causado pelo processo de denitrificação, que diminuiu a concentração de nitrogênio em 72% do inicio ao final do sistema, levando este nutriente em quantidades insuficientes para a área agrícola. Estes resultados serão utilizados para indicar caminhos de melhorias no sistema. Ainda, quanto aos resultados isotópicos, foi possível concluir que: a água sofre um fracionamento durante o processo de osmose reversa na ordem de 1,87 para o 18O e 10,3 para o 2H; A água do poço é formada por uma mistura de águas recentes e paleoáguas; A relação 18O vs 2H; possui um coeficiente angular de 4,1, indicando elevada evaporação neste elemento; O solo avaliado possui uma média isotópica de -24 de 13C no solo de caatinga e -20 de 13C na área experimental, indicando uma troca da matéria orgânica desta área por material proveniente da Atriplex, que teve uma razão isotópica média de -13,7 .de 13C. / Isotopic, physical and chemical analysis were performed in water, soil and plants of the \" Integrated Production System Using Wastewater Desalination \", created Embrapa Semiarid, as an alternative to reuse of wastewater for food production and reducing the environmental impact caused by the incorrect disposal of the reject. The evaluated system is located in the Experimental Área Caatinga at Embrapa Semi-Arid (Petrolina-PE). The findings about the cycling of nutrients indicated the occurrence of a continuous addition of Ca+2, Mg+2, K+ and Na+ in the soil during the experiment of, 199 kg ha-1, 88 kg ha-1, 51 kg ha-1 and 142 kg ha-1, respectively. The efficiency of removal of Ca+2, Mg+2 and Na+ by Atriplex nummularia was 12,1, 4,3 and 23,9% respectively; Was observed high loss of nitrogen in the system caused by denitrification process, which decreased the concentration of nitrogen by 72% from beginning to end system, taking this nutrient in insufficient quantities to agricultural area. These results will be used for indicate ways to improve the system. Also, with the isotopic results was concluded that: water undergoes fractionation during the process of reverse osmosis the order of 1,87 to 18O and 10,3 for 2H; The well water is formed by a mixture of recent water and paleoáguas; The relationship 18O vs 2H; has a slope of 4,1, indicating high evaporation of this element; The soil has an average rated -24 in isotopic 13C in savanna soi and -20 of 13C in the experimental area, indicating an exchange of matter of this area of organic material from Atriplex, which had an average isotopic ratio of -13,7 . of 13C.
42

Juvenis de bijupirá Rachycentron canadum criados em salinidade reduzida: a adição de NaCl na dieta pode afetar o desempenho do crescimento e a osmorregulação?

Santos, Renato Adriano dos January 2011 (has links)
Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Aqüicultura, Instituto de Oceanografia, 2011. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2012-08-20T13:42:19Z No. of bitstreams: 1 dissertao renato a santos.pdf: 788840 bytes, checksum: d822bbd2dd77094d946ed0d5d725098d (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-11-13T22:09:12Z (GMT) No. of bitstreams: 1 dissertao renato a santos.pdf: 788840 bytes, checksum: d822bbd2dd77094d946ed0d5d725098d (MD5) / Made available in DSpace on 2012-11-13T22:09:12Z (GMT). No. of bitstreams: 1 dissertao renato a santos.pdf: 788840 bytes, checksum: d822bbd2dd77094d946ed0d5d725098d (MD5) Previous issue date: 2011 / Organismos marinhos em salinidades reduzidas encontram um desafio fisiológico diferente daquele naturalmente encontrado em salinidade oceânica. Isso ocorre porque esses se tornam hiper-osmóticos em relação ao meio. A literatura sugere que a adição de sal na dieta pode suprir a perda passaiva de íons e, consequentemente, melhorar o crescimento. Dessa forma, os efeitos da suplementação de sal na dieta (SD) no crescimento, na sobrevivência, na osmorregulação e nas alterações histológicas branquiais foram avaliados em juvenis de bijupirá (12 g) criados em salinidade 5. O bijupirá, Rachycentron canadum, tem recebido a atenção de pesquisadores e investidores no mundo inteiro devido às suas características positivas que a elegem uma espécie com potencial na piscicultura marinha. Durante 40 dias, os peixes foram alimentados, diariamente em dois turnos, com dietas contendo diferentes níveis de NaCl: 0,0; 2,5; 5,0; 7,5 e 10,0% do peso seco da dieta basal (todos em triplicata). Ao final do experimento os arcos branquiais foram coletados para avaliação histológica e determinação da atividade Na+, K+-ATPase. A sobrevivência foi 100% em todos os grupos e não houve diferença no peso médio final entre os tratamentos. Entretanto, 7,5 e 10% de NaCl resultaram em piores taxas de conversão alimentar e maior consumo alimentar comparadas aos demais grupos. A atividade da Na+, K+-ATPase branquial foi estatisticamente reduzida quando os peixes receberam dietas com níveis de 2,5; 5 e 7,5% de NaCl em relação ao grupo 0,0%. O número de células de cloreto do grupo controle (16 células mm-2) diferiu significativamente dos grupos SD. Foi verificado o aumento da proliferação celular de acordo com o aumento do sal na dieta, atingindo 41 células mm-2 nas brânquias dos peixes do grupo 10% de NaCl. Esses dados sugerem que a suplementação de NaCl não é necessária para o crescimento em salinidade 5, apesar do bijupirá apresentar menor atividade Na+, K+-ATPase nos grupos com baixa adição de NaCl na dieta. / Marine fish in low-saline water encounter the physiological challenge of passive loss of ions and water gain. Some studies suggested that dietary salt can provide physiological necessities and may, consequently, improve growth. Cobia Rachycentron canadum is a fast growing fish and its commercial interest has been increasing around the world. The aim of this study was to investigate the influence of salty diet (SD) on growth performance, gill histological alterations, and osmoregulation of cobia reared in low salinity. Cobia juveniles (12 g) were acclimated to salinity 5 and fed with five dietary NaCl levels: 0.0%, 2.5%, 5.0%, 7.5% and 10.0% dry weight of a basal diet (all with three replicates). Fishes were fed twice daily until satiation for 40 days. At the end of experiment, gill arches were sampled for histological evaluation and for determination of Na+, K+-ATPase activity. Survival after 40 days was 100% in all treatments. The results showed that NaCl supplementation did not improve growth performance and the highest levels of SD (7.5 and 10%) showed unfavorable effects on food conversion and feed intake. Na+, K+-ATPase activity in fishes fed with the basal diet was significantly higher than in those fed with 2.5%, 5.0 and 7.0% NaCl supplementation. The number of chloride cells significantly increased with increasing dietary salt level, reaching 2.5 fold higher in 10% NaCl supplementation (41 cells mm-2) when compared to group 0.0% (16 cells mm-2). Summarily, dietary salt supplemented has consequences on chloride cells proliferation, but, apparently, cobia seems to spare energy, since it reduced the Na+, K+-ATPase activity.
43

Modelling, Simulation, Optimisation and Thermodynamic Analysis of Multistage Reverse Osmosis Process based Brackish Water Desalination

Alsarayreh, Alanood A. January 2020 (has links)
The Reverse Osmosis (RO) process has been considered to be one of the most widely utilised techniques for brackish water desalination for its capabilities to produce high-quality water. The RO process characterised by its low energy consumption compared to thermal distillation processes, leading to reduced overall water production cost. To systematically understand the transport phenomena of solvent and solutes via the membrane texture, several mathematical models were developed. This interestingly aids to conduct a huge amount of simulation and optimisation studies to judge the influence of control variables on the performance indexes and to adjust the key variables at optimum values to realise optimum production indexes. In this research, a specific accurate model for a single spiral wound RO process has been successfully developed and used to build accurate models for the multistage brackish water RO desalination process of two different designs. The robustness of the model developed was confirmed via validation against the experimental data collected from simple design of RO system and complicated design of RO system of Arab Potash Company (APC). This is followed by a thorough simulation of the RO process to explore the influence of operating conditions on the process performance indicators. Recently, several contributions were made in this thesis that specifically comprises the improvement of the original design of brackish water RO desalination process. The influence of a retentate recycle design is investigated on the process performance. Moreover, evaluation and minimisation of specific energy consumption (expressed in kWh/m3 of freshwater production) is carried out on the simple and complicated designs of RO process by implementing an energy recovery device. Also, the most suitable brand of membranes was explored for the RO system from a set of different brands of membrane to attain the highest-performance rejection at lowest energy consumption compared to the original membrane. Furthermore, a single optimisation framework was developed to mitigate the specific energy consumption of simple and complicated designs of brackish water RO desalination process. Finally, a thermodynamic limitations and exergy analysis of the complicated design of RO system are outlined via a thoroughly study to investigate the locations of high exergy destruction. These contributions were verified as they promoted the separation performance at a significant energy saving. / Mutah University, Jordan
44

The skeletal remains of the naval ship Mars : An osteological pre-study for analysing digitally documented skeletalremains in a marine context

Fredriksson, Matilda January 2015 (has links)
Denna kandidatuppsats är ämnad att ligga som grund för framtida osteologisk dokumentation ochanalys av de skeletala kvarlevorna från skeppet Mars, och är utförd i samarbete med projektet SkeppetMars (1564).Syftet med denna uppsats är att undersöka och problematisera möjligheterna att analyseradigitalt dokumenterade skeletala kvarlevor i en marin miljö. För att utvärdera möjligheterna ochbegränsningarna med att utföra en digital osteologisk analys utfördes en mindre studie av det digitaltdokumenterade material som hittills insamlats från skeppet Mars. Analysen visade att en osteologiskanalys kan utföras på digitalt dokumenterade skeletala kvarlevor men att det finns begränsningar medatt utföra en analys av ett två dimensionellt källmaterial. Syftet med denna uppsats är även attdiskutera och lyfta fram hur skeletala kvarlevor påverkas under längre tid i marina sediment* samtbräckt/salt vatten. Syftet med denna uppsats är även att diskutera hur en hypotetisk inhämtning och konservering av de skeletala kvarlevorna från skeppet Mars bör utföras. / This bachelor's thesis is intended to lay the ground for future osteological documentation and analysisof the skeletal remains from the naval ship Mars, and is conducted with the project Skeppet Mars(1564). The main purpose of this thesis is to examine and problematise the possibility to analysedigitally documented skeletal remains in a marine context. In order to evaluate the possibilities andlimitations of performing an osteological analysis, a small analysis was conducted on the digitallydocumented skeletal remains collected from the naval ship Mars so far. The analysis showed that anosteological analysis can be performed on digitally documented skeletal remains, there are, however,limitations of performing an analysis on a two dimensional documentation. The secondary purpose ofthis thesis is to discuss and highlight how skeletal remains are affected by marine sediment* andbrackish/saltwater over a long period of time. An additional goal for this thesis is to discuss how ahypothetical retrieval and conservation of the skeletal remains of the naval ship Mars shouldpreferably be performed.
45

Versatilité écologique de la cyanobactérie potentiellement toxique Planktothrix agardhii : influence de la salinité?

Vergalli, Julia 12 July 2013 (has links)
La recherche a été initiée par l'observation d'efflorescences de Planktothrix agardhii, une cyanobactérie dulçaquicole potentiellement toxique, dans deux étangs saumâtres, les étangs de l'Olivier et de Bolmon, avec dans ce dernier le déclin de l'espèce concomitamment à une augmentation de salinité. L'objectif de l'étude consistait à évaluer l'influence de la salinité du milieu sur la performance, l'hégémonie et la production de toxine de Planktothrix agardhii au sein de la communauté phytoplanctonique.La réalisation de suivis pluriannuels in situ couplés à des expérimentations en milieu contrôlé a permis de démontrer (i) la capacité d'acclimatation et d'adaptation à la salinité de Planktothrix agardhii, laquelle garantit sa suprématie et sa production toxinique en milieu saumâtre ; et (ii) la modification structurale et fonctionnelle de la communauté phytoplanctonique suite à une augmentation de salinité supérieure au seuil d'halotolérance de Planktothrix agardhii. La recherche témoigne ainsi de la versatilité des cyanobactéries qui renforce leur aptitude à être de bons compétiteurs, laissant présager leur persistance, la continuité de leurs nuisances, et leur expansion dans le futur. / The research was launched by the observation of Planktothrix agardhii blooms, a potentially toxic freshwater cyanobacterium, in two brackish ponds, the Olivier and Bolmon ponds, with in the latter, the concomitantly collapse of P. agardhii with an increase in salinity. The goal of the study was to assess the salinity influence on the performance, the dominance and the toxin production of P. agardhii within the phytoplankton community.The achievement of a long-term monitoring in situ combined with batch cultures experiments has demonstrated (i) the ability of P. agardhii to acclimate and adapt to salinity, which ensure its supremacy and its toxin production in brackish areas, and (ii) the structural and functional changes of the phytoplankton community with the exceeding of the salt-tolerance threshold of P. agardhii .The research reflects the cyanobacteria versatility that enhances their suitability for being good performers, suggesting their persistence along with their nuisances, and their expansion in the future.
46

EFICIÊNCIA DE UM SISTEMA DE DESSALINIZAÇÃO DE ÁGUA SALOBRA UTILIZANDO ULTRAFILTRAÇÃO E OSMOSE REVERSA

Almeida, Juliano Penteado de 20 April 2017 (has links)
Made available in DSpace on 2017-07-20T13:42:00Z (GMT). No. of bitstreams: 1 Juliano Almeida.pdf: 2689795 bytes, checksum: e2c63ba0cfcdfb76d39a3d5e44e5dcf9 (MD5) Previous issue date: 2017-04-20 / Considering the shortage of fresh water availability and an increased demand for water in the world, including Brazil, one of the alternatives for water supply are the water desalination system, which remove salts from brackish or seawater. The objective of this study was to evaluate the efficiency of treated water desalination system with production capacity of 1.0 m3 h-1 of treated water, installed in a water treatment plant of Sanepar (Water and Sanitation Company of the State of Parana), in Praia de Leste located in the coast of the state of Paraná, Brazil. In this study, the seawater was diluted with fresh water to make brackish water. The brackish water was prepared from the water mixture of the Pombas River, source of fresh water supply to the region, and sea water. The mixtures were performed to obtain concentrations of 1000 and 1500 mg L-1 of total dissolved solids (TDS). The system was composed of ultrafiltration (UF) as a pre-treatment to reverse osmosis (RO). Experiments were performed during 15 days for each TDS concentration of brackish water and TDS removal efficiencies were 99.0 and 99.1%, respectively. Besides TDS, other water quality parameters such as: electrical conductivity, turbidity, apparent colour, alkalinity, total hardness, calcium, magnesium, chlorides, sulphates and pH were monitored. Oxidation-reduction potential (ORP) and osmotic pressure, filtration rate and membrane recovery rate were also measured for the RO. The pilot plant system could remove all water quality parameters studied. / Com a escassez da disponibilidade de água doce e o aumento da demanda de água no mundo e também no Brasil, uma das alternativas para o suprimento de água são os sistemas de dessalinização de água, que removem os sais da água salobra ou salgada. Este trabalho teve como objetivo avaliar a eficiência de um sistema piloto de dessalinização de água salobra com capacidade de produção de 1,0 m3 h-1 de água tratada, instalado na estação de tratamento de água (ETA) da Sanepar, no balneário de Praia de Leste, no litoral do estado do Paraná. A água salobra foi preparada a partir da mistura da água bruta do Rio das Pombas, manancial que abastece o balneário, e água do mar. As misturas foram realizadas até obter concentrações de 1000 e 1500 ± 100 mg L-1 de sólidos dissolvidos totais (SDT). O sistema foi composto de ultrafiltração como pré-tratamento à osmose reversa. Os experimentos foram realizados durante o período de 15 dias para cada concentração de SDT da água salobra obtendo-se remoções de 99,0 e 99,1%, para 1500 ± 100 mg L-1 e 1000 ± 100 mg L-1, respectivamente. Além dos SDT, foram avaliados outros parâmetros de qualidade da água como: condutividade elétrica, turbidez, cor aparente, alcalinidade, dureza total, cálcio, magnésio, cloretos, sulfatos, pH e temperatura. Durante os experimentos foram avaliados potencial de oxirredução (ORP) e a pressão osmótica, a taxa de filtração e a taxa de recuperação na membrana de osmose reversa. O sistema de ultrafiltração foi mais eficiente na remoção de turbidez e cor aparente, sendo que o sistema de osmose reversa apresentou melhor eficiência na remoção de sólidos dissolvidos totais.
47

Etude biostratigraphique des assemblages de diatomées pyritisées des sédiments du Paléocène supérieur et de l'Eocène inférieur des Bassins Danois, de Dieppe-Hampshire et Belge - apports paléoenvironnementaux/Biostratigraphic study of the pyritised diatom assemblages from the Upper Paleocene and Lower Eocene sediments of the Danish, Dieppe-Hampshire and Belgian Basins

Van Eetvelde, Yoann 15 June 2005 (has links)
La distribution stratigraphique des diatomées pyritisées et leur répartition paléogéographique sont étudiées dans les sédiments du Paléocène supérieur et principalement de l’Eocène inférieur des Bassins Danois (Ølst et Hinge), de Dieppe-Hampshire (Saint-Josse et Ailly) et Belge (Knokke). Différents types de fossilisation ont été observés. D’une part, dans un stade précoce de la diagenèse, un moulage du frustule est construit par la croissance de minéraux authigéniques (pyrite et barytine). D’autre part, le frustule siliceux est remplacé épigénitiquement par de la pyrite. Ces deux processus de fossilisation, pouvant coexister, gardent les diatomées identifiables. Une méthodologie fiable et reproductible pour l’extraction de ces dernières a été mise en point. Une évolution des zones de diatomées (zonation) est mise en évidence : quatre zones (D0 à D3) d’association ou d’abondance et deux sous-zones (D3a et D3b) sont reconnues. Cette zonation est établie pour les bassins méridionaux et orientaux du Bassin de la Mer du Nord. Elle est corrélable avec les biozonations de King (1983), Fenner (1985), Mudge & Copestake (1992a) et Mitlehner (1994, 1996) valables pour la partie centrale du Bassin de la Mer du Nord. Les zones D0 à D3 autorisent les corrélations entre les unités lithostratigraphiques des différents bassins étudiés et celui de la Mer du Nord. Cela a permis, entre autres, de corréler les sédiments des faciès sparnaciens du Bassin de Dieppe-Hampshire aux formations de la Mer du Nord. Enfin, les diatomées pyritisées sont un nouvel argument pour encadrer la position de la C.I.E. (dont la base est le critère de reconnaissance de la limite Paléocène-Eocène), celle-ci étant située dans la partie inférieure de la zone D1 sous le pic d’abondance de l’espèce Coscinodiscus morsianus var. moelleri. / The stratigraphic distribution of the pyritized diatoms and their paleogeographic repartition are studied in Upper Paleocene and especially Lower Eocene from the Danish (Ølst Hinge), Dieppe-Hampshire (Saint-Josse and Ailly) and Belgian (Knokke) Basins. Different kinds of fossilisation are observed. In a first step of the diagenesis, a mould of the frustule is built thanks to the growth of authigenic minerals (pyrite and barite). The siliceous skeleton may also be completely replaced epigenetically by pyrite. These two types of fossilisation, that may coexist, keep diatoms identifiable. A reliable and reproducible methodology for the extraction of pyritized diatoms has been developed. The evolution of the diatom zones is underlined : four zones (D0 until D3) of association or abundance are recognized. This zonation is established for the southern and eastern basins of the North Sea Basin. It is interrelated with the biozonations of King (1983), Fenner (1985), Mudge & Copestake (1992a) and Mitlehner (1994, 1996) valid for the central part of the North Sea Basin. The zones D0-D3 allow correlations between the lithostratigraphic units of the various studied basins and the one of the North Sea. This enables among others to correlate the sediments of the sparnacien facies of the Dieppe-Hampshire with the formations of the North Sea. At last, the pyritized diatoms represent a new argument to locate the C.I.E. which base is the criterion for the identification of the Paleocene-Eocene boundary. The C.I.E. is located in the lower part of the D1 zone under the abundance peak of the Coscinodiscus morsianus var. moelleri species.
48

Aquatic macrophyte and animal communities in a recently restored brackish marsh: possible influences of restoration design and the invasive plant species Myriophyllum spicatum

Bell, Michael Thomas 2011 May 1900 (has links)
The numerous benefits that wetlands provide make them essential to ecosystem services and ecological functions. Historically, wetland losses have been caused by natural and anthropogenic changes. In Texas, nearly 50% of coastal wetland habitat has been lost since the 1930s and losses in the Lower Neches watershed have been some of the most extensive. Restoration is a way to mitigate these losses and can be accomplished in many ways. Each restoration design creates different aquatic habitats that can influence both submerged aquatic vegetation (SAV) and faunal communities. The restoration of the Lower Neches Wildlife Management Area (LNWMA) has created the conditions for the growth of the invasive submerged macrophyte, Myriophyllum spicatum (Eurasian watermilfoil) which may be competing with the native aquatic grass, Ruppia maritima (widgeongrass) for essential nutrients. In this study, an attempt was made to link restoration design with both SAV and aquatic fauna community structures by using a throw trap to characterize assemblages observed in three different types of restored marshes. We also performed two controlled mesocosm experiments in 0.5 gal aquariums to determine growth inhibition by M. spicatum on R. maritima. Analyses using Kruskal-Wallis non-parametric test determined that temporal variations in fauna and SAV community composition was greater than any restoration effect. Discriminant Function Analyses (DFAs) determined two to three key faunal species that best predicted association among restoration designs, but linear regressions could not determine any consistent relationship between individual species density and biomass of the dominant SAV species, M. spicatum. For the mesocosm experiments, M. spicatum inhibited the biomass production and branch count of R. maritima when the two species are grown together (ANOVA, p = 0.004 and 0.003, respectively). Changes in SAV assemblages due to competition and habitat characteristics could play a major role in determining faunal community. In order to minimize the temporal effect observed and better determine any habitat pattern that may be present, a much longer study is necessary.
49

Beyond the Aquifer : planning for San Antonio's future water supply

Laughlin, Nathan Daniel 24 November 2010 (has links)
This report examines water supply planning issues in San Antonio, Texas. San Antonio is unique among large cities in the United States in that it relies almost exclusively on a single source, the Edwards Aquifer, for its water supply. Because San Antonio’s water demand is projected to outgrow the Aquifer’s capacity, the city must consider other options to extend and augment its current water supply. After describing the hydrogeology and water supply history of San Antonio, this report explains the multitiered water planning structure and current and future water needs for the city. It then studies and evaluates three short-to-mid term water supply options. By continuing to develop its already successful water conservation programs and water reclamation system, San Antonio can delay the need for more costly and environmentally impactful water supply options down the road, and wisely manage the resources it already draws from. / text
50

Modelagem e simulação da dessalinização de águas salobras usando um separador ciclônico térmico munido de bicos aspersores. / Modeling and simulation of brackish water desalination using a thermal cyclonic separator with sprinkler nozzles.

SILVA, Akleino Silvestre da. 16 March 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-03-16T19:29:28Z No. of bitstreams: 1 AKLEINO SILVESTRE DA SILVA - DISSERTAÇÃO PPGEQ 2016..pdf: 6288381 bytes, checksum: f65c5bdc20bfda0cdb5930837d5d1894 (MD5) / Made available in DSpace on 2018-03-16T19:29:28Z (GMT). No. of bitstreams: 1 AKLEINO SILVESTRE DA SILVA - DISSERTAÇÃO PPGEQ 2016..pdf: 6288381 bytes, checksum: f65c5bdc20bfda0cdb5930837d5d1894 (MD5) Previous issue date: 2016-09-29 / O consumo de água doce vem crescendo muito no mundo inteiro e sua possível escassez tornou-se um dos temas mais discutidos na atualidade. Com isso há necessidade de desenvolver novas estratégias para suprir a falta de água potável. Dentre elas, destacam-se a dessalinização. Neste sentido, o presente trabalho tem por objetivo avaliar um ciclone convencional utilizado para dessalinização da água salgada com adição de cinco bicos injetores, localizados na parte superior do mesmo. O modelo matemático adotado considera escoamento tridimensional, turbulento, estacionário e não isotérmico para a fase gasosa, e a aplicação do modelo Lagrangeano para as partículas. As equações de conservação da massa, de momento linear, de energia e as do modelo de turbulência SST , bem como as equações constitutivas e as condições de contorno foram resolvidas com auxílio do software comercial Ansys CFX. São apresentados os resultados dos campos de pressão, temperatura, velocidade e fração mássica, linhas de fluxo, trajetórias das partículas, perfis de velocidade, de pressão total e de temperatura total no interior do separador ciclônico térmico. Constatouse o caráter tridimensional do escoamento gás-partícula no interior do ciclone com presenças de regiões de zonas de recirculação e de inversão de fluxo. Os resultados mostraram que a variação das temperaturas na alimentação, tanto do ar como da água, influência na geração de vapor no interior do separador ciclônico. Porém é preciso um estudo cauteloso, como por exemplo, avaliar a influência do comprimento da parte cônica, tanto na fluidodinâmica quanto na cinética, para tentar aumentar o tempo de residência das partículas e com isso contribuir para o aquecimento da partícula. / The consumption of fresh water has been increasing worldwide and its possible shortage has become one of the most discussed topics today. With this, there is a need to develop new strategies to address the lack of potable water. Among them, desalination. In this sense, the present work aims to evaluate a conventional cyclone used for the desalination of salt water with the addition of five injector nozzles, located in the upper part of the same. The mathematical model adopted considers three-dimensional, turbulent, stationary and nonisothermal flow for the gas phase, and the application of the Lagrangian model to the particles. The equations of conservation of mass, linear momentum, energy and those of the SST w turbulence model, as well as the constitutive equations and the boundary conditions were solved with the commercial software Ansys CFX. The results of the fields of pressure, temperature, velocity and mass fraction, flow lines, particle trajectories, velocity profiles, total pressure and total temperature inside the thermal cyclone separator are presented. It was noted three-dimensional character of the gas-particle flow within the cyclone presence regions with recirculation zones and reverse flow. The results showed that the temperature variation in both air and water influences the generation of steam inside the cyclonic separator. However, a cautious study is required, for example, to evaluate the influence of the length of the conic part, both in fluid dynamics and kinetics, to try to increase the residence time of the particles and thereby contribute to the heating of the particle.

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