• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 17
  • Tagged with
  • 17
  • 17
  • 15
  • 11
  • 11
  • 11
  • 10
  • 9
  • 9
  • 8
  • 7
  • 6
  • 6
  • 5
  • 3
  • 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.
11

Imobiliza??o f?sica de l?quidos i?nicos em suportes porosos para separa??o de CO2 do g?s natural

Polesso, B?rbara Burlini 27 July 2018 (has links)
Submitted by PPG Engenharia e Tecnologia de Materiais (engenharia.pg.materiais@pucrs.br) on 2018-11-26T11:03:21Z No. of bitstreams: 1 diss_final_Barbara_pgetema.pdf: 1961642 bytes, checksum: e697bce70379b05d18b7de59fe7b4784 (MD5) / Approved for entry into archive by Caroline Xavier (caroline.xavier@pucrs.br) on 2018-11-27T16:37:44Z (GMT) No. of bitstreams: 1 diss_final_Barbara_pgetema.pdf: 1961642 bytes, checksum: e697bce70379b05d18b7de59fe7b4784 (MD5) / Made available in DSpace on 2018-11-27T16:43:10Z (GMT). No. of bitstreams: 1 diss_final_Barbara_pgetema.pdf: 1961642 bytes, checksum: e697bce70379b05d18b7de59fe7b4784 (MD5) Previous issue date: 2018-07-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / An efficient and low-cost strategy in the search for processes for the separation of CO2 from the natural gas is the physical immobilization of the ionic liquids (ILs) in solid materials. Mesoporous silicas are interesting materials to be used as supports because they have high surface area and pore volume. Besides that, the ionic liquids have been studied and appointed as a potential substitute for the commercial solvents, due to their characteristics and the possibility of combining a selection of anions and cations. In this case, anions having direct interference in the sorption capacity. In this context, the objective of this study was to evaluate the effect of the physical immobilization of two ionic liquids with different anions (bmim [Cl] and bmim [OAc]) on two mesoporous supports (commercial silica SBA-15 and silica extracted from rice husk) for the separation of CO2 from the natural gas through the experimental determination of CO2 sorption, selectivity (CO2/CH4) and sorption kinetics. The results have shown that pure solid supports have the greatest sorption capacity of CO2 when compared to immobilized. However, the CO2 removal efficiency in the CO2/CH4 mixture of the immobilized supports (evaluated by the selectivity) improves considerably. The best selectivity results were obtained for supports immobilized with the IL bmim[Cl] and the contribuition of SIL-Cl (3.03 ? 0.12) to separation performance (CO2/CH4) is similar to SBA-Cl (3.29 ? 0.39). The materials supported with ionic liquids have also presented fastest sorption kinetics when compared to the pure ILs. Also, the SIL-Cl was the most interesting combination of support and ionic liquid, when considering these parameters and the cost. / Uma estrat?gia interessante na busca de processos para separa??o de CO2 do g?s natural mais eficiente e de baixo custo ? a imobiliza??o f?sica de l?quidos i?nicos (LIs) em materiais s?lidos. As s?licas mesoporosas s?o materiais interessantes para a utiliza??o como suportes, pois apresentam grande ?rea superficial e volume de poros, j? os l?quidos i?nicos v?m sendo estudados e apontados como potencial substituinte aos solventes comerciais, devido a suas caracter?sticas e possibilidade de combina??o atrav?s da escolha de c?tions e ?nions, sendo que os ?nions t?m interfer?ncia direta na capacidade de sor??o. Neste contexto, o objetivo deste trabalho foi avaliar o efeito da imobiliza??o f?sica de dois l?quidos i?nicos com ?nions diferentes (bmim[Cl] e bmim[OAc]) em dois suportes mesoporosos (s?lica comercial SBA-15 e s?lica extra?da da casca de arroz) para separa??o de CO2 do g?s natural atrav?s da determina??o experimental da sor??o de CO2, seletividade (CO2/CH4) e cin?tica de sor??o. Os resultados mostraram que os suportes s?lidos puros tem a maior capacidade de sor??o do CO2 quando comparados com os imobilizados, entretanto a efici?ncia de remo??o do CO2 na mistura CO2/CH4 (avaliada pela seletividade) dos suportes imobilizados melhora consideravelmente. Os melhores resultados de seletividade foram obtidos com os suportes imobilizados com o LI bmim[Cl] e a contribui??o de SIL-Cl (3,03 ? 0,12) para a separa??o (CO2/CH4) foi similar a SBA-Cl (3,29 ? 0,39). Os materiais suportados com l?quidos i?nicos tamb?m apresentaram cin?tica de sor??o r?pida quando comparados com os LIs puros, sendo SIL-Cl a combina??o mais interessante de suporte e l?quido i?nico, considerando estes par?metros e o custo.
12

Imobiliza??o f?sica de l?quidos i?nicos em suportes porosos para separa??o de CO2 do g?s natural

Polesso, B?rbara Burlini 27 July 2018 (has links)
Submitted by PPG Engenharia e Tecnologia de Materiais (engenharia.pg.materiais@pucrs.br) on 2018-11-28T12:43:18Z No. of bitstreams: 1 diss_final_Barbara_pgetema.pdf: 1961642 bytes, checksum: e697bce70379b05d18b7de59fe7b4784 (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-11-29T10:34:05Z (GMT) No. of bitstreams: 1 diss_final_Barbara_pgetema.pdf: 1961642 bytes, checksum: e697bce70379b05d18b7de59fe7b4784 (MD5) / Made available in DSpace on 2018-11-29T10:54:06Z (GMT). No. of bitstreams: 1 diss_final_Barbara_pgetema.pdf: 1961642 bytes, checksum: e697bce70379b05d18b7de59fe7b4784 (MD5) Previous issue date: 2018-07-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / An efficient and low-cost strategy in the search for processes for the separation of CO2 from the natural gas is the physical immobilization of the ionic liquids (ILs) in solid materials. Mesoporous silicas are interesting materials to be used as supports because they have high surface area and pore volume. Besides that, the ionic liquids have been studied and appointed as a potential substitute for the commercial solvents, due to their characteristics and the possibility of combining a selection of anions and cations. In this case, anions having direct interference in the sorption capacity. In this context, the objective of this study was to evaluate the effect of the physical immobilization of two ionic liquids with different anions (bmim [Cl] and bmim [OAc]) on two mesoporous supports (commercial silica SBA-15 and silica extracted from rice husk) for the separation of CO2 from the natural gas through the experimental determination of CO2 sorption, selectivity (CO2/CH4) and sorption kinetics. The results have shown that pure solid supports have the greatest sorption capacity of CO2 when compared to immobilized. However, the CO2 removal efficiency in the CO2/CH4 mixture of the immobilized supports (evaluated by the selectivity) improves considerably. The best selectivity results were obtained for supports immobilized with the IL bmim[Cl] and the contribuition of SIL-Cl (3.03 ? 0.12) to separation performance (CO2/CH4) is similar to SBA-Cl (3.29 ? 0.39). The materials supported with ionic liquids have also presented fastest sorption kinetics when compared to the pure ILs. Also, the SIL-Cl was the most interesting combination of support and ionic liquid, when considering these parameters and the cost. / Uma estrat?gia interessante na busca de processos para separa??o de CO2 do g?s natural mais eficiente e de baixo custo ? a imobiliza??o f?sica de l?quidos i?nicos (LIs) em materiais s?lidos. As s?licas mesoporosas s?o materiais interessantes para a utiliza??o como suportes, pois apresentam grande ?rea superficial e volume de poros, j? os l?quidos i?nicos v?m sendo estudados e apontados como potencial substituinte aos solventes comerciais, devido a suas caracter?sticas e possibilidade de combina??o atrav?s da escolha de c?tions e ?nions, sendo que os ?nions t?m interfer?ncia direta na capacidade de sor??o. Neste contexto, o objetivo deste trabalho foi avaliar o efeito da imobiliza??o f?sica de dois l?quidos i?nicos com ?nions diferentes (bmim[Cl] e bmim[OAc]) em dois suportes mesoporosos (s?lica comercial SBA-15 e s?lica extra?da da casca de arroz) para separa??o de CO2 do g?s natural atrav?s da determina??o experimental da sor??o de CO2, seletividade (CO2/CH4) e cin?tica de sor??o. Os resultados mostraram que os suportes s?lidos puros tem a maior capacidade de sor??o do CO2 quando comparados com os imobilizados, entretanto a efici?ncia de remo??o do CO2 na mistura CO2/CH4 (avaliada pela seletividade) dos suportes imobilizados melhora consideravelmente. Os melhores resultados de seletividade foram obtidos com os suportes imobilizados com o LI bmim[Cl] e a contribui??o de SIL-Cl (3,03 ? 0,12) para a separa??o (CO2/CH4) foi similar a SBA-Cl (3,29 ? 0,39). Os materiais suportados com l?quidos i?nicos tamb?m apresentaram cin?tica de sor??o r?pida quando comparados com os LIs puros, sendo SIL-Cl a combina??o mais interessante de suporte e l?quido i?nico, considerando estes par?metros e o custo.
13

Sor??o de CO2 com l?quido i?nico aditivado com extensores de ?rea superficial / Sorption of CO2 with ionic liquid additivated with surface area extenders

Souza, Andr? Luiz Anton de 23 March 2017 (has links)
Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-06-30T13:47:33Z No. of bitstreams: 1 DIS_ANDRE_LUIZ_ANTON_DE_SOUZA_COMPLETO.pdf: 1015461 bytes, checksum: 70dfda26cefa98999779334ff862f5c0 (MD5) / Made available in DSpace on 2017-06-30T13:47:33Z (GMT). No. of bitstreams: 1 DIS_ANDRE_LUIZ_ANTON_DE_SOUZA_COMPLETO.pdf: 1015461 bytes, checksum: 70dfda26cefa98999779334ff862f5c0 (MD5) Previous issue date: 2017-03-23 / In recent years the scientific community has a growing interest in studying environmentally friendly agents sorption of carbon dioxide to be used in substitution of chemical solvents based on amines. Among the technologies studied for this purpose are those which use Ionic liquids that have the advantage of having very low vapor pressures, higher density than water, a low melting point and a desorption low energy; These qualities that make them environmentally friendly solvents, compared with volatile organic solvents. Moreover ionic liquids are chemically and thermally stable and can be used at relatively high temperatures, its physical-chemical properties can be designed by varying the substitutive groups of the cation or the combined ion. These characteristics make ionic liquids potentially important for the development of new processes focused on the mitigation of global warming. Otherwise the ionic liquids have a high viscosity, they are expensive making them economically unfeasible for use in conventional processes with liquid gas absorption columns. On the other side are available in the market the bubble glass that have several applications in the industry, have low cost, high chemical and physical resistance. This work evaluated in isochoric saturation cell, the carbon dioxide solubility in mixed systems with boron silicate bubble glass, with volumetric concentrations of 5% to 50%, in the ionic liquids [Bmim][BF4] and [mBmim] [NTf2] as well as with pure ionic liquids. Data are reported at 27 Bar pressure and at temperatures 303, 313, and 323 K. Mixed systems with 50% concentration of bubble glass showed the best results of sorption and cost for both ionic liquids. / Nos ?ltimos anos existe na comunidade cient?fica um crescente interesse em estudar agentes de sor??o de di?xido de carbono ambientalmente amig?veis para serem utilizados em substitui??o aos solventes qu?micos baseados em aminas. Entre as tecnologias estudadas para este fim est?o aquelas que utilizam os l?quidos I?nicos (LI). Estes compostos apresentam como caracter?stica diferencial baix?ssima press?o de vapor, densidade maior que a da ?gua, baixo ponto de fus?o e baixa energia de regenera??o; qualidades estas que os tornam solventes ambientalmente amig?veis quando comparados com os solventes org?nicos vol?teis. Por?m a alta viscosidade e custo limitam o uso dos Lis. Estudos realizados com sistemas mistos de LIs e part?culas s?lidas tem mostrado que tais part?culas podem potencializar a a??o dos Lis, assim se identificou as microesferas de vidro, dispon?veis no mercado, onde possuem diversas aplica??es na ind?stria, baixo custo, alta resist?ncia qu?mica e f?sica. Neste trabalho foram avaliados sistemas mistos (Lis + microesferas de vidro boro silicato) visando melhorar as propriedades dos Lis. Para avaliar estes novos sistemas foram obtidos em c?lula de satura??o isoc?rica, dados experimentais de solubilidade do di?xido de carbono, nas concentra??es volum?tricas de 5% a 50%. Foram avaliados os LIs [Bmim] [BF4] e [mBmim] [NTf2] para obter os sistemas mistos, assim como puros. Os dados s?o reportados na press?o de 27 Bar e nas temperaturas 303, 313, e 323 K. Os sistemas mistos com concentra??o de 50% de microesferas apresentaram os melhores resultados combinados de capacidade de sor??o e custo para ambos os l?quidos i?nicos.
14

Poli (l?quidos i?nicos) celul?sicos aplicados como catalisadores heterog?neos para transforma??o qu?mica do CO2 em carbonatos c?clicos

Rodrigues, Daniela Maffi 27 July 2018 (has links)
Submitted by PPG Engenharia e Tecnologia de Materiais (engenharia.pg.materiais@pucrs.br) on 2018-12-03T15:52:09Z No. of bitstreams: 1 Dissertacao DANIELA MAFFI RODRIGUES.pdf: 1641622 bytes, checksum: 7201a3a551a602c84d3776d0f02f7399 (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-12-05T13:35:48Z (GMT) No. of bitstreams: 1 Dissertacao DANIELA MAFFI RODRIGUES.pdf: 1641622 bytes, checksum: 7201a3a551a602c84d3776d0f02f7399 (MD5) / Made available in DSpace on 2018-12-05T13:50:46Z (GMT). No. of bitstreams: 1 Dissertacao DANIELA MAFFI RODRIGUES.pdf: 1641622 bytes, checksum: 7201a3a551a602c84d3776d0f02f7399 (MD5) Previous issue date: 2018-07-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Carbon capture and storage (CCS) and carbon capture and utilisation(CCU) technologies has been pointed out as possibilities to mitigate the effects caused by the massiverelease of CO2 into the atmosphere. The use of CO2 in cycloaddition reactions toepoxides obtaining cyclic carbonates is an interesting possibility to reduce CO2emission. Cyclic carbonates are products of great applicability as solvents in the chemical industry and are used as raw material for a wide range of products. Meanwhile, the use of CO2 for a cycloaddition reaction requires a large amount of energy being necessary the use of catalysts in order to optimize such reactions. Poly (ionic liquids) (PIL) are alternative catalysts due its selective, recyclability and conversion. In this work, cellulosic poly(ionic liquids) (CPIL) obtained from rice husk were testedas heterogeneous catalyst. Cellulose extraction was carried out by chemical method. A chemical modification of the cellulose fibers was carried out by the treatment with citric acid and functionalization with 3 mmol of the ionic liquids BMIM Cl, TBAB, TBPB and BMPYRR to form CPIL-BMIM, CPIL-TBA, CPIL-TBP and CPIL-BMPYRR), without addition of solvents. Cyclo addition reactions were carried out with propylene and styrene oxides with different CO2 pressures(25, 30 and 40 bar) and temperatures (90, 110 and 120 ?C) for 6 h. The obtained product was characterized by gas chromatography (GC), Fourier Transform Infrared Spectroscopy(FTIR)and Nuclear Magnetic Resonance (1H NMR). The results showed better yields for CPIL-TBP and CPIL-TBA, whose values were 53.2% and 39% respectively for propylene carbonate and 67.3% for styrene carbonate using CPIL-TBP. When the ZnBr2 cocatalyst was used, there was an increase in the catalytic activity of these catalysts. For CPIL-TBP the yields were 71.4% for propylene carbonate and 78.7% for styrene carbonate. For CPIL-TBA the increase in propylene carbonate yield was 67.7%. / O uso das tecnologias de captura e armazenamento de carbono (CCS) e de captura utiliza??o do carbono (CCU) v?m sendo apontadas como possibilidades para mitigar os efeitos causados pela libera??o deliberada de elevadas concentra??es de CO2 na atmosfera. A utiliza??o do CO2 em rea??es de cicloadi??o em ep?xidos para obter carbonatos c?clicos vem se mostrando uma possibilidade interessante para reduzir a emiss?o de CO2 na atmosfera. Os carbonatos c?clicos s?o produtos de grande aplicabilidade como solventes na ind?stria qu?mica e s?o utilizados como mat?ria prima para uma vasta gama de produtos. Entretanto, o CO2 apresenta baixa reatividade tornando-se necess?rio o uso de catalisadores para otimizar tais rea??es. Os poli(l?quidos i?nicos) (PILs) v?m se mostrando como poss?veis catalisadores alternativos, demonstrando-se seletivos, recicl?veis e gerando consider?vel convers?o. Neste trabalho foram testados poli(l?quidos i?nicos) celul?sicos (CPIL), obtidos a partir da casca do arroz, como catalisador heterog?neo. A extra??o da celulose foi realizada por um m?todo qu?mico. A modifica??o qu?mica das fibras de celulose foi realizada a partir do tratamento com ?cido c?trico e a funcionaliza??o desta com 3 mmol dos l?quidos i?nicos BMIM Cl, TBAB, TBPB e BMPYRR formando CPIL-BMIM, CPIL-TBA, CPIL-TBP e CPIL-BMPYRR. As rea??es de cicloadi??o foram realizadas com os ?xidos de propileno e estireno com diferentes press?es de CO2 (15, 25, 30 e 40 bar) e temperaturas (90, 110, 120 e 130?C) durante (3, 6 e 9h), todas as rea??es foram realizadas sem a utiliza??o de solventes. O produto obtido foi caracterizado por cromatografia gasosa (CG) , espectroscopia de infravermelho com transformada de Fourier (FTIR) e Resson?ncia Magn?tica Nuclear (1H RMN). Os resultados demonstraram melhores rendimentos para CPIL-TBP e CPIL-TBA, cujos valores foram de 53,2% e 39% respectivamente para o carbonato de propileno e de 67,3% para o carbonato de estireno utilizando o CPIL-TBP. Quando o cocatalisador ZnBr2 foi utilizado, houve um aumento na a atividade catal?tica destes catalisadores, para o CPIL-TBP os rendimentos foram de 71,4 % para o carbonato de propileno e 78,7% para o carbonato de estireno. Para o CPIL-TBA o aumento no rendimento de carbonato de propileno foi de 67,7%.
15

Estimador de estados para Plunger Lift

Dourado J?nior, Osmar de Ara?jo 19 June 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-01-24T12:15:33Z No. of bitstreams: 1 OsmarDeAraujoDouradoJunior_TESE.pdf: 3621125 bytes, checksum: ac4c7dbcd5830c2fa16d1e8be1ae3ee1 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-01-26T14:00:19Z (GMT) No. of bitstreams: 1 OsmarDeAraujoDouradoJunior_TESE.pdf: 3621125 bytes, checksum: ac4c7dbcd5830c2fa16d1e8be1ae3ee1 (MD5) / Made available in DSpace on 2018-01-26T14:00:19Z (GMT). No. of bitstreams: 1 OsmarDeAraujoDouradoJunior_TESE.pdf: 3621125 bytes, checksum: ac4c7dbcd5830c2fa16d1e8be1ae3ee1 (MD5) Previous issue date: 2017-06-19 / O objetivo desta Tese ? apresentar um Estimador de Estado para po?os de Plunger Lift com base no algoritmo Extended Kalman Filter (EKF). O estimador de estado ? uma opera??o conjunta da aplica??o para o modelo din?mico de Plunger Lift (PL) na abordagem de Espa?o de Estados e algoritmo EKF. O modelo ? constitu?do por um conjunto de equa??es diferenciais e alg?bricas (DAEs) discretas e modeladas na forma de equa??es no espa?o de estados, levando em conta os sinais de medi??o na presen?a de ru?do. O algoritmo EKF ? aplicado ao modelo de espa?o de estado, resultando num estimador de estado capaz de processar o sinal de medi??o, proporcionando assim estimativas das vari?veis de estado, que neste problema s?o a velocidade da golfada e a press?o no topo do revestimento. A simula??o computacional realizada com dados de um po?o real ? apresentada e os resultados mostraram que o estimador de estados proposto ? capaz de fornecer predi??es para po?os de petr?leo operados por PL. / The aim of this Thesis is to present a State Estimator for Plunger Lift wells based on the Extended Kalman Filter (EKF) algorithm. The state estimator is a joint operation of the application for the Plunger Lift (PL) dynamic model in State Space approach and EKF algorithm. The model is constituted by a set of discrete differential algebraic equations (DAEs) discretized and modeled in the form of equations in state space taking into account the measurement signals in the presence of noise. EKF algorithm is applied to the state space model, resulting in a state estimator able to process the measurement signal thus providing estimates of the state variables, that in this problem are slug velocity and casinghead pressure. The computational simulation performed with data from a real well is presented and the results showed that the state estimator proposed is able to provide predictions for oil wells operated by PL.
16

Acur?cia dos indicadores cl?nicos do diagn?stico de enfermagem volume de l?quidos excessivo em pacientes submetidos ? hemodi?lise / Accuracy of clinical indicators of nursing diagnosis excessive fluid volume in patients undergoing hemodialysis

Fernandes, Maria Isabel da Concei??o Dias 27 January 2014 (has links)
Made available in DSpace on 2014-12-17T14:47:04Z (GMT). No. of bitstreams: 1 MariaICDF_DISSERT.pdf: 1911495 bytes, checksum: b33fd53ec7c7e2b2d0bd96f5e0ea12e9 (MD5) Previous issue date: 2014-01-27 / Trasnversal study, with the objective of evaluating the accuracy of clinical indicators of nursing diagnosis excessive fluid volume in patients undergoing hemodialysis. The study occurred in two stages, the first consisted of the evaluation of the diagnostic indicators in study; and the second, the diagnostic inference conducted by nurse diagnosticians. The first stage occurred from december 2012 to april 2013, in a University Hospital and a Hemodialysis Clinic in Northeastern of Brazil, with a sample of 100 chronic renal failure patients on hemodialysis. The data were selected through an interview form and a physical examination, organized into spreadsheets and analyzed as to the presence or absence of the indicators of diagnosis excessive fluid volume. In the second step, the spreadsheets were sent to three nurses diagnosticians, who judged the presence or absence of diagnosis in the clientele searched. This step was conducted from july to september 2013. For analysis of the data, we used descriptive and inferential statistics. In the descriptive analysis, we used measures of central tendency and dispersion. In inferential analysis, we used the tests Chi- square, Fisher and prevalence ratios. The accuracy of the clinical indicators pertaining to the diagnosis were measured as to the specificity, sensitivity, predictive values, likelihood ratios and Diagnostic Odds Ratio. Also developed a logistic regression. The results were organized in tables and discussed with literature. This study was approved by the Ethics Committee in Research of the Federal University of Rio Grande do Norte, with Presentation Certificate for Ethics Appreciation n? 08696212.7.0000.5537. The results revealed that the diagnosis studied was present in 82% of patients. The characteristics with prevalence above 50 % that stood out were: azotemia, decreased hematocrit, electrolyte imbalance, intake exceeds output, anxiety, edema, decreased hemoglobin, oliguria and blood pressure changes. Eight defining characteristics were presented statistically significant association with the nursing diagnosis investigated: pulmonary congestion, intake exceeds output, electrolytes imbalance, jugular vein distension, edema, weight gain over short period of time, agitation and adventitious breath sounds. Among these, the 10 characteristics which showed higher prevalence ratios were: edema and weight gain over short period of time. The features with the highest sensitivity were edema, electrolytes imbalance and intake exceeds output and the standing out with greater specificity were: anasarca, weight gain over short period of time, change in respiratory pattern, adventitious breath sounds, pulmonary congestion, agitation and jugular vein distension. The indicators jugular vein distension, electrolytes imbalance, intake exceeds output, increased central venous pressure and edema, together, were identified in the logistic regression model as the most significant predictors. It is concluded that the identification of accurate clinical indicators allow a good prediction of the nursing diagnosis of excessive fluid volume in patients undergoing hemodialysis in order to assist the nurse in the inference process, which will contribute to the success of patient care. In addition, nurses will consider for diagnostic inference not only his clinical experience, but also scientific evidence of the occurrence of excessive fluid volume, contributing to the control of volemia in these patients / Estudo transversal, com o objetivo de avaliar a acur?cia dos indicadores cl?nicos do diagn?stico de enfermagem Volume de l?quidos excessivo em pacientes submetidos ? hemodi?lise. Ocorreu em duas etapas, a primeira composta pela avalia??o dos indicadores do diagn?stico em estudo; e a segunda, pela infer?ncia diagn?stica realizada por enfermeiros diagnosticadores. A primeira etapa aconteceu nos meses de dezembro de 2012 a abril de 2013, em um Hospital Universit?rio e em uma Cl?nica de Hemodi?lise do Nordeste do Brasil, com uma amostra de 100 pacientes renais cr?nicos submetidos ? hemodi?lise. Os dados foram obtidos mediante formul?rio de entrevista e exame f?sico, organizados em planilhas eletr?nicas e analisados quanto ? presen?a ou aus?ncia dos indicadores do diagn?stico Volume de l?quidos excessivo. Na segunda etapa, as planilhas foram encaminhadas a tr?s diagnosticadores, que julgaram a presen?a ou aus?ncia do diagn?stico na clientela pesquisada. Essa etapa desenvolveu-se nos meses de julho a setembro de 2013. Para a an?lise dos dados, utilizou-se a estat?stica descritiva e inferencial. Na an?lise descritiva, utilizaram-se medidas de tend?ncia central e de dispers?o. Na inferencial, utilizaram-se os testes de Qui-quadrado, Fisher e as raz?es de preval?ncia. Mensurou-se a acur?cia dos indicadores cl?nicos do diagn?stico estudado por meio da especificidade, da sensibilidade, dos valores preditivos, das raz?es de verossimilhan?a e da Odds Ratio Diagn?stica. Desenvolveu-se tamb?m uma regress?o log?stica. Os resultados foram organizados em tabelas e discutidos com literatura pertinente. O estudo foi aprovado pelo Comit? de ?tica da Universidade Federal do Rio Grande do Norte, com Certificado de Apresenta??o para Aprecia??o ?tica n? 08696212.7.0000.5537. Os resultados revelaram que o diagn?stico de enfermagem estudado esteve presente em 82% dos pacientes. Dentre as caracter?sticas com preval?ncia acima de 50% destacaram-se: azotemia, hemat?crito diminu?do, eletr?litos alterados, ingest?o maior que o d?bito, ansiedade, edema, hemoglobina diminu?da, olig?ria e mudan?a na press?o arterial. 8 Apresentaram associa??o estatisticamente significativa com o diagn?stico de enfermagem investigado oito caracter?sticas definidoras: congest?o pulmonar, ingesta maior que o d?bito, eletr?litos alterados, distens?o da jugular, edema, ganho de peso em um curto per?odo de tempo, agita??o e ru?dos advent?cios. Dentre estas, as que apresentaram maiores raz?es de preval?ncia foram edema e ganho de peso em um curto per?odo de tempo. A caracter?stica com maior sensibilidade foi o edema e sobressa?ram-se com maior especificidade ru?dos advent?cios, congest?o pulmonar e agita??o. Os indicadores distens?o da jugular, eletr?litos alterados, ingesta maior que o d?bito, press?o venosa central aumentada e edema, em conjunto, foram identificados no modelo da regress?o como as caracter?sticas preditoras mais significantes. Conclui-se que a identifica??o de indicadores cl?nicos acurados permite uma boa predi??o do diagn?stico de enfermagem Volume de l?quidos excessivo em pacientes submetidos ? hemodi?lise, de modo a auxiliar no processo de infer?ncia do enfermeiro, o que contribuir? no sucesso do cuidado prestado ao paciente. Al?m disso, os enfermeiros considerar?o para a infer?ncia diagn?stica n?o apenas sua experi?ncia cl?nica, mas tamb?m evid?ncias cient?ficas da ocorr?ncia do Volume de l?quidos excessivo, contribuindo para o controle da volemia nesses pacientes
17

Degrada??o catal?tica de polietileno de alta densidade sobre a ze?lita HZSM

Lima, Stevie Hallen 31 August 2009 (has links)
Made available in DSpace on 2014-12-17T15:41:46Z (GMT). No. of bitstreams: 1 StevieHLpdf.pdf: 1475886 bytes, checksum: e83c49569bddebb612701e2de7e607bc (MD5) Previous issue date: 2009-08-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In last years it has talked a lot about the environment and the plastic waste produced and discarded. In last decades, the increasing development of research to obtain fuel from plastic material, by catalytic degradation, it has become a very attractive looking, as these tailings are discarded to millions worldwide. These materials take a long time to degrade themselves by ways said natural and burning it has not demonstrated a viable alternative due to the toxic products produced during combustion. Such products could bring serious consequences to public health and environment. Therefore, the technique of chemical recycling is presented as a suitable alternative, especially since could be obtain fractions of liquid fuels that can be intended to the petrochemical industry. This work aims to propose alternatives to the use of plastic waste in the production of light petrochemical. Zeolites has been widely used in the study of this process due to its peculiar structural properties and its high acidity. In this work was studied the reaction of catalytic degradation of high-density polyethylene (HDPE) in the presence HZSM-12 zeolites with different acid sites concentrations by thermogravimetry and pyrolysis coupled with GC-MS. The samples of the catalysts were mixed with HDPE in the proportion of 50% in mass and submitted to thermogravimetric analyses in several heating rates. The addition of solids with different acid sites concentrations to HDPE, produced a decrease in the temperature of degradation of the polymer proportional the acidity of the catalyst. These qualitative results were complemented by the data of activation energy obtained through the non-isothermal kinetics model proposed by Vyazovkin. The values of Ea when correlated to the data of surface acidity of the catalysts indicated that there is a exponential decrease of the energy of activation in the reaction of catalytic degradation of HDPE, in function of the concentration of acid sites of the materials. These results indicate that the acidity of the catalyst added to the system is one of the most important properties in the reaction of catalytic degradation of polyethylene / Nos ?ltimos anos tem-se falado muito sobre o meio ambiente e sobre o lixo pl?stico produzido e descartado. Nas ?ltimas d?cadas, o crescente desenvolvimento de pesquisas com o intuito de obter combust?veis a partir de material pl?stico, via degrada??o catal?tica, tem-se tornado uma busca muito atrativa, j? que esses rejeitos s?o descartados aos milh?es em todo mundo. Esses materiais levam muito tempo para se degradar por meios ditos naturais e sua incinera??o n?o tem se demonstrado uma alternativa vi?vel devido aos produtos t?xicos produzidos durante sua combust?o. Tais produtos conseq?entes poderiam trazer s?rios problemas de sa?de p?blica e ambiental. Logo, a t?cnica da reciclagem qu?mica apresenta-se como uma alternativa adequada, inclusive porque podemos obter fra??es leves do petr?leo que podem ser destinadas ao setor petroqu?mico. Este trabalho tem como objetivo propor alternativas para o aproveitamento de lixo pl?stico na produ??o de combust?veis l?quidos. Ze?litas tem sido amplamente utilizada no estudo desse processo devido ?s suas propriedades estruturais peculiares e sua alta acidez. Neste trabalho, investigou-se a rea??o de degrada??o de Polietileno de Alta Densidade (PEAD) na presen?a de HZSM-12, com diferentes concentra??es de s?tios ?cidos, atrav?s da termogravimetria e pir?lise acoplada ? cromatografia ? g?s e ao espectr?metro de massa (Py-GC-MS). As amostras de catalisadores foram misturadas com PEAD na propor??o de 50% em massa e submetidas a an?lises em diferentes taxas de aquecimento. A adi??o de catalisadores com diferentes concentra??es de s?tios ?cidos produziu uma diminui??o na temperatura de degrada??o do pol?mero proporcional ? acidez do catalisador. Estes resultados qualitativos foram complementados por dados da energia de ativa??o (Ea) obtidos atrav?s do modelo cin?tico n?o-isot?rmico proposto por Vyazovkin. Os valores das Ea quando correlacionados com os dados da acidez superficial dos catalisadores, indicaram que h? uma redu??o exponencial da Ea da rea??o catal?tica de degrada??o em fun??o da concentra??o dos s?tios ?cidos dos materiais, indicando que esta propriedade ? significativa neste tipo de rea??o

Page generated in 0.0179 seconds