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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.
1

Colloid Formation for the Removal of Natural Organic Matter during Iron Sulfate Coagulation

Masters, Erika N. 31 July 2003 (has links)
Removal of organic matter is increasingly important to drinking water utilities and consumers. Organic matter is a significant precursor in the formation of disinfection by-products (DBPs). The maximum contaminant levels for (DBPs) are decreasing and more DBPs are believed carcinogenic. Traditional coagulation focuses on the removal of particulate matter and in the last decade soluble species have also been targeted with high coagulant doses. However, colloidal matter is smaller than particulate matter and therefore not easily removed by conventional drinking water treatment. This research focused on the conversion of soluble organic matter to colloids using relatively low doses of ferric sulfate coagulant and the subsequent removal of the colloids by filtration during drinking water treatment. The goal is to achieve enhanced removal of soluble organic matter with minimal chemical costs and residual formation. This study investigated the effects of pH, iron coagulant dose, turbidity, organic matter concentration, and temperature on colloid formation. Characterization of the colloidal organic matter was attempted using zeta potential and sizing analyses. Cationic low molecular weight, nonionic high molecular weight, and cationic medium molecular weight polymers were evaluated on their removal of colloidal organic matter. Colloidal organic matter formation was affected by changes in coagulation pH, coagulant dose, and organic matter concentration, whereas turbidity and temperature did not significantly impact colloid formation. Decreased coagulation pH caused increased organic carbon removal. As coagulant dose was increased, colloid formation initially increased to maximum and subsequently rapidly decreased. Colloid formation was increased as the organic matter concentration increased. Due to low sample signal, the colloids could not be characterized using zeta potential and sizing analyses. In addition, polymers were ineffective for aggregating colloidal organic matter when used as flocculant aids. / Master of Science
2

Prevalência de anemia e fatores de risco associados, em crianças de 06 a 24 meses no município do Guarujá / Prevalence of anemia and correlated risk factors in 06 to 24 months old children in the municipality of Guarujá

Bettini, Rosana Ana 25 August 2010 (has links)
Introdução: A anemia por deficiência de ferro em crianças é um dos maiores problemas nutricionais enfrentados pelos países em desenvolvimento. As crianças menores de dois anos constituem o grupo de maior risco, tendo como principais causas a depleção dos estoques de ferro no nascimento e o aumento da demanda devido ao crescimento acelerado que ocorre neste período. Objetivo: O objetivo desta pesquisa é verificar a prevalência de anemia e fatores de risco associados, em crianças de 06 a 24 meses no Município do Guarujá visando valores base para o monitoramento do Programa Nacional de Suplementação de Ferro (PNSF) instituído no Brasil em 2005. Métodos: A metodologia adotada é a da pesquisa de campo, tendo a autorização da Secretaria Municipal de Saúde do Município do Guarujá e sendo desenvolvida nas Unidades Básicas de Saúde (UBS) selecionadas, durante a Campólio. Teve o consentimento livre e esclarecido dos responsáveis pelas crianças, os quais responderam também a um questionário sobre características sociais, econômicas e hábitos alimentares da família. Todas as crianças presentes nas UBS, durante a Campólio, pertencentes à faixa etária estudada, foram submetidas ao exame de hemoglobina para diagnosticar a presença da anemia. Resultados: - Foram pesquisadas 531 crianças entre 06 e 24 meses e o resultado obtido revelou a prevalência de anemia em 50,5 por cento, sendo que 18,5 por cento da população total apresentou anemia grave (hemoglobina <=9,5g/dL). As crianças mais vulneráveis à anemia foram aquelas com idade entre 6 a 12 meses (59,8 por cento de anêmicos). A maior renda familiar tem interferência diretamente inversa às taxas de hemoglobina, assim como a idade da mãe ao parto. Quanto aos fatores dietéticos, observa-se que a alimentação infantil é semelhante à da família. Estão presentes na alimentação infantil carnes e feijão, fontes naturais de ferro; e pão, macarrão e bolachas que são alimentos fortificados com o mineral, porém, todos são ingeridos em pequenas quantidades. Conclusões: - Há, portanto, uma alta prevalência de anemia entre as crianças observadas, o que justifica a necessidade de intervenções preventivas como o Programa Nacional de Suplementação de Ferro (PNSF). Fica evidente que os lactentes são um grupo de risco para a deficiência de ferro, considerando as inúmeras consequências deletérias acarretadas por essa carência nutricional, o PNSF apresenta uma perspectiva importante para o controle dessa desnutrição / Anemia due to iron deficiency in children is one of the greatest nutrition problems challenging developing countries. Young children with less than two years of age are the greatest risk group. Main causes are iron depletion at birth and the increase in iron demand due to the accelerated growth of children in this period. Objectives are to verify the prevalence of anemia and correlated risk factors in 06 to 24 months children in the municipality of Guarujá in order to obtain base values for the monitoring of the National Program of Iron Supplementation implemented in Brazil in 2005. The work was authorized by the Department of Health of the Municipality of Guarujá and was developed in Basic Health Care Units (UBS) during the Campolio. Parents of the children gave their informed consent to the trial. Parents were also requested to answer a questionnaire on the social and economic characteristics and dietary habits of the family. All children in the studied age bracket present at the UBS, during the Campolio, had their hemoglobin tested to diagnose anemia. 531 children from 06 to 24 mo were tested. Prevalence of anemia was 50.5 per cent, and 18.5 per cent of the total population had severe anemia (hemoglobin <=9,5g/dL). Children from 6 to 12 mo were more vulnerable (59,8 per cent) Higher family income has directly inverse impact on hemoglobin levels as well as age of mother at delivery. As for dietary habits, the children\'s diet is very similar to that of the family. Children eat beef and beans, natural sources of iron, and bread, pasta and biscuits that are enriched with the mineral. However the intake and quantities are small. The findings of this study show high prevalence of anemia in the subjects observed therefore actions such as the implementation of the PNSF (National Program for Iron Supplementation) is necessary. Children in nursing age are a risk group for iron deficiency and all deleterious consequences considered, the National Program for Iron Supplementation will allow for the control of this malnutrition
3

Prevalência de anemia e fatores de risco associados, em crianças de 06 a 24 meses no município do Guarujá / Prevalence of anemia and correlated risk factors in 06 to 24 months old children in the municipality of Guarujá

Rosana Ana Bettini 25 August 2010 (has links)
Introdução: A anemia por deficiência de ferro em crianças é um dos maiores problemas nutricionais enfrentados pelos países em desenvolvimento. As crianças menores de dois anos constituem o grupo de maior risco, tendo como principais causas a depleção dos estoques de ferro no nascimento e o aumento da demanda devido ao crescimento acelerado que ocorre neste período. Objetivo: O objetivo desta pesquisa é verificar a prevalência de anemia e fatores de risco associados, em crianças de 06 a 24 meses no Município do Guarujá visando valores base para o monitoramento do Programa Nacional de Suplementação de Ferro (PNSF) instituído no Brasil em 2005. Métodos: A metodologia adotada é a da pesquisa de campo, tendo a autorização da Secretaria Municipal de Saúde do Município do Guarujá e sendo desenvolvida nas Unidades Básicas de Saúde (UBS) selecionadas, durante a Campólio. Teve o consentimento livre e esclarecido dos responsáveis pelas crianças, os quais responderam também a um questionário sobre características sociais, econômicas e hábitos alimentares da família. Todas as crianças presentes nas UBS, durante a Campólio, pertencentes à faixa etária estudada, foram submetidas ao exame de hemoglobina para diagnosticar a presença da anemia. Resultados: - Foram pesquisadas 531 crianças entre 06 e 24 meses e o resultado obtido revelou a prevalência de anemia em 50,5 por cento, sendo que 18,5 por cento da população total apresentou anemia grave (hemoglobina <=9,5g/dL). As crianças mais vulneráveis à anemia foram aquelas com idade entre 6 a 12 meses (59,8 por cento de anêmicos). A maior renda familiar tem interferência diretamente inversa às taxas de hemoglobina, assim como a idade da mãe ao parto. Quanto aos fatores dietéticos, observa-se que a alimentação infantil é semelhante à da família. Estão presentes na alimentação infantil carnes e feijão, fontes naturais de ferro; e pão, macarrão e bolachas que são alimentos fortificados com o mineral, porém, todos são ingeridos em pequenas quantidades. Conclusões: - Há, portanto, uma alta prevalência de anemia entre as crianças observadas, o que justifica a necessidade de intervenções preventivas como o Programa Nacional de Suplementação de Ferro (PNSF). Fica evidente que os lactentes são um grupo de risco para a deficiência de ferro, considerando as inúmeras consequências deletérias acarretadas por essa carência nutricional, o PNSF apresenta uma perspectiva importante para o controle dessa desnutrição / Anemia due to iron deficiency in children is one of the greatest nutrition problems challenging developing countries. Young children with less than two years of age are the greatest risk group. Main causes are iron depletion at birth and the increase in iron demand due to the accelerated growth of children in this period. Objectives are to verify the prevalence of anemia and correlated risk factors in 06 to 24 months children in the municipality of Guarujá in order to obtain base values for the monitoring of the National Program of Iron Supplementation implemented in Brazil in 2005. The work was authorized by the Department of Health of the Municipality of Guarujá and was developed in Basic Health Care Units (UBS) during the Campolio. Parents of the children gave their informed consent to the trial. Parents were also requested to answer a questionnaire on the social and economic characteristics and dietary habits of the family. All children in the studied age bracket present at the UBS, during the Campolio, had their hemoglobin tested to diagnose anemia. 531 children from 06 to 24 mo were tested. Prevalence of anemia was 50.5 per cent, and 18.5 per cent of the total population had severe anemia (hemoglobin <=9,5g/dL). Children from 6 to 12 mo were more vulnerable (59,8 per cent) Higher family income has directly inverse impact on hemoglobin levels as well as age of mother at delivery. As for dietary habits, the children\'s diet is very similar to that of the family. Children eat beef and beans, natural sources of iron, and bread, pasta and biscuits that are enriched with the mineral. However the intake and quantities are small. The findings of this study show high prevalence of anemia in the subjects observed therefore actions such as the implementation of the PNSF (National Program for Iron Supplementation) is necessary. Children in nursing age are a risk group for iron deficiency and all deleterious consequences considered, the National Program for Iron Supplementation will allow for the control of this malnutrition
4

Aplica??o da termogravimetria na determina??o do teor de ferro em comprimidos: um estudo comparativo com a espectrofotometria

Silva, Marcia Lima da 19 August 2014 (has links)
Made available in DSpace on 2014-12-17T15:42:21Z (GMT). No. of bitstreams: 1 MarciaLS_DISSERT.pdf: 3817212 bytes, checksum: 089f2e43de0c72515df1302d1f7136f9 (MD5) Previous issue date: 2014-08-19 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This study used the Thermogravimetry (TG) and molecular absorption spectroscopy in UV-visible region to determine the iron content in herbal medicinal ferrous sulfate used in the treatment of iron deficiency anemia. The samples were characterized by IR, UV, TG / DTG, DTA, DSC and XRD. The thermoanalytical techniques evaluated the thermal stability and physicochemical events and showed that the excipients interfere in the decomposition of the active ingredients. The results of thermogravimetry showed that the decomposition temperature of the active principle Fe2(SO4)3 (T = 602 ?C) is higher as compared to samples of tablets (566 586 ?C). In the DTA and DSC curves were observed exothermic and endo events for samples of medicines and active analysis. The infrared spectra identified key functional groups exist in all samples of active ingredients, excipients and compressed studied, such as symmetric and asymmetric stretching of OH, CH, S=O. The analysis by X-ray diffraction showed that all samples had crystallinity and the final residue showed peaks indicating the presence of silicon dioxide, titanium dioxide and talc that are excipients contained in pharmaceutical formulations in addition to iron oxide. The results obtained by TG to determine the iron content of the studied drugs showed a variance when compared with those obtained by theoretical and UV-visible, probably due to formation of a mixture of Fe2O3 and Fe2(SO4)3. In one tablet was obtained FE content of 15.7 % and 20.6 % for TG by UV-visible, the sample EF 2 was obtained as a percentage of 15.4 % and 21.0 % for TG by UV-visible . In the third SF samples were obtained a content of 16.1 % and 25.5 % in TG by UV-visible, and SF 4 in the percentage of TG was 16.7 % and 14.3 % UV-visible / O presente trabalho utilizou a termogravimetria (TG) e a espectroscopia de absor??o molecular na regi?o UV-vis?vel para determinar o teor de ferro em medicamentos ? base de sulfato ferroso usados no tratamento da anemia ferropriva. As amostras foram caracterizadas por IV, UV, TG/DTG, DTA, DSC e DRX. As t?cnicas termoanal?ticas avaliaram a estabilidade t?rmica e os eventos f?sico-qu?micos e mostraram que os excipientes interferem na decomposi??o do princ?pio ativo. Os resultados da Termogravimetria indicaram que a temperatura de decomposi??o do Fe2(SO4)3 (T = 602 ?C) ? superior em compara??o as amostras dos comprimidos (566 a 586 ?C). Nas curvas DTA e DSC foram observados eventos endo e exot?rmicos para as amostras dos medicamentos e princ?pio ativo analisado. Os espectros de infravermelho identificaram os principais grupos funcionais existentes em todas as amostras de princ?pios ativos, excipientes e comprimidos estudados, tais como estiramentos sim?tricos e assim?tricos dos grupos O-H, C-H, S=O. As an?lises por difra??o de raios- X mostraram que todas as amostras apresentaram cristalinidade e que os res?duos finais mostraram picos indicativos da presen?a de di?xido de sil?cio, di?xido de tit?nio e talco que s?o excipientes contidos nas formula??es farmac?uticas, al?m do ?xido de ferro. Os resultados obtidos por TG para determinar o teor de ferro dos medicamentos estudados mostraram uma varia??o quando comparados aos obtidos pelo UV-vis?vel e o te?rico, provavelmente devido a forma??o de uma mistura de Fe2O3 e Fe2(SO4)3. No comprimido FE 1 foi obtido um teor de 15,7 % pela TG e 20,6 % pelo UV-vis?vel, na amostra FE 2 obteve-se um percentual de 15,4 % pela TG e 21,0 % pelo UV-vis?vel. Nas amostras FE 3 obteve-se um teor de 16,1 % na TG e 25,5 % pelo UV-vis?vel, e em FE 4 o percentual na TG foi de 16,7 % e no UV-vis?vel 14,3 %
5

Jarosite Formation at the Davis Mine, Rowe, Massachusetts

Miller, Karen S. 01 January 2011 (has links) (PDF)
This study investigates jarosite formation and stability patterns at the abandoned Davis Pyrite Mine in Rowe, Massachusetts. Jarosite, an iron-sulfate hydroxide, is found in acid mine drainage (AMD) environments, in acid sulfate soils, and on Mars. Jarosite and the iron oxides goethite and hematite are present at the site. Soil samples from the site were examined by XRD, SEM, and EDS. Five mineralogical areas were found, based on mineral abundance patterns. Jarosite exists in four of these areas. Two jarosite morphologies were identified. “Variable” jarosite, with partly-dissolved crystals of about 0.5 to 5 micrometers diameter, exists in spoil pile samples. “Donut” jarosite, with tightly-packed, sharp-edged crystals less than 0.5 micrometers that form a thin mantle on the surface of a second mineral, exists in native soil samples. Donut jarosite has not been previously characterized. These jarosite morphologies are controlled by the presence and relative mobility of pyrite oxidation products Fe and SO4, which in turn are controlled by water saturation levels. Three pathways are possible. On Path 1, both ions are mobile, go into solution, and variable jarosite forms at a distance from the pyrite source. On Path 2, only sulfur ions are mobile, an iron-oxide gossan develops. No jarosite forms. On Path 3, neither ion is mobile, and donut jarosite forms. On this path, Fe and SO4 ions are trapped in a thin film of stagnant water covering the pyrite. When sufficient ions are present, donut jarosite precipitates.

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