• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 1
  • Tagged with
  • 6
  • 6
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 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

Raman spectroscopy applied to iron oxide pigments from waste materials and earthenware archaeological objects

Legodi, Malebogo Andries 06 June 2008 (has links)
Raman spectroscopy is a vibrational spectroscopic technique. It gives a unique combination of non-destructive analysis, high spatial resolution and phase characterisation. In the current study Raman spectroscopy was used as the primary technique during the study of chemical components in archaeological earthenware samples (i.e. low temperature fired clay pottery) of South African and Chinese origin, and characterisation of iron oxides derived from mill scale. One shard from each of the South African archaeological sites (Rooiwal, Lydenburg, Makahane and Graskop) was analysed by Raman spectroscopy, FT-IR spectroscopy, X-ray fluorescence (XRF) spectroscopy and X-ray diffractometry (XRD). The common features observed were montmorillonite (Mg3(Si,Al)4(OH)2.4.5H2O[Mg]0.35), kaolin (Al2Si2O5(OH)5), quartz (α-SiO2), feldspar (K- and NaAlSi3O8), hematite (α-Fe2O3), calcium silicate (CaSiO3) and illite (KAl4(Si7AlO20)(OH)4). Gypsum (CaSO4.2H2O) and calcium carbonates (CaCO3) were detected in Lydenburg, Makahane and Graskop shards. Amorphous carbon was observed in Lydenburg and Makahane shards while rutile appeared only in Makahane shard. The Lydenburg and Rooiwal shards showed the presence of anhydrite (CaSO4). The Chinese clay samples investigated by Raman spectroscopy were from the J A Van Tilburg museum at the University of Pretoria. The large red shard was recovered from the 1552 Portuguese shipwreck, São João, found around Port Edward, South Africa. Four other shards (two red and two gray) were recovered from the 1622 Portuguese shipwreck, the São João Baptista, found around Kenton-on-Sea off the South African coast. A 19th century Chinese teapot was also analysed. Hematite, kaolin, quartz, amorphous carbon and aluminosilicates were observed in all three red shards. All these components, except quartz, were also observed in the teapot. The gray shards showed the presence of quartz, kaolin, amorphous carbon and aluminosilicates. The pigments identified were hematite (in red samples) and black amorphous carbon (in all samples). Magnetite and goethite were precipitated from mill scale-derived precursors in aqueous media. Hematite was then prepared from the calcination of goethite at 750°C and maghemite from the thermal treatment of magnetite at 200°C. The iron oxides were characterised by Raman spectroscopy, XRD, surface area determination and scanning electron microscopy (SEM). They were generally composed of very small sized particles showing high surface area values. / Thesis (PHD)--University of Pretoria, 2008. / Chemistry / unrestricted
2

A Groundwater Vulnerability Assessment Method Using GIS and Multivariate Statistics - Gotland, Sweden.

Pirnia, Seyed Amir January 2012 (has links)
Concentrations of microorganisms and chemical components in groundwater are serious threats for groundwater resources sustainability and contribute to technical and health problems. Recent studies and reports in Gotland revealed huge concerns about water quality in the area. In this master thesis a range of methods such as GIS and statistical analysis including multivariate analysis and non-parametric analysis, have been used in order to identify natural and human factors which affect groundwater contamination. Main focus of the study was on using existing data and available databases in analyses. Consequently, several important factors such as land use, overlaying soil cover, soil thickness, bedrock, elevation, distance to deformation and fracture zones and slope were evaluated considering 8 variables including micro-organisms and chemical components. The results clarified several significant factors which statistically affected the micro-biological and chemical components of groundwater. These relations can be used for development of risk maps which can be used in spatial planning.
3

Monitoramento de componentes químicos da vinhaça aplicados em diferentes tipos de solo / Monitoring the fate and transport of vinasse chemical components applied to different soil types

Lelis Neto, João Alberto 02 February 2009 (has links)
Desde a época da colonização, a cana-de-açúcar apresenta-se como um dos principais produtos da agricultura brasileira e, além disso, trata-se de um tipo importante de biomassa energética, servindo como base para todo o agronegócio sucroalcooleiro, responsável por empregos diretos e indiretos em todo o Brasil. Do seu processo de industrialização são obtidos produtos, tais como: o açúcar, o álcool (anidro e hidratado), o bagaço e a vinhaça. Nesse sentido, diante do aspecto da aplicação da vinhaça em práticas agrícolas, pode-se dizer que sempre ocorre a sua associação com processos de impactos ambientais. Assim sendo, conduziu-se a presente pesquisa buscando-se monitorar a dinâmica, em diferentes tipos de solo, de componentes químicos presentes na vinhaça, bem como, elaborar curvas de distribuição de efluentes presentes na vinhaça. A pesquisa foi conduzida em área experimental do Departamento de Ciências Exatas da ESALQ/USP, em casa de vegetação, onde foram distribuídas 50 bombonas, em blocos casualizados. A vinhaça foi coletada na Usina Costa Pinto do grupo COSAN no município de Piracicaba/SP e as dosagens de aplicação foram: 100 m³ ha-1; 150 m³ ha-1; 200 m³ ha-1; 250 m³ ha-1 e 300 m³ ha-1. As espécies analisadas foram: nitrato e potássio, assim como, o pH, condutividade elétrica e cálcio. As curvas de distribuição de efluentes foram confeccionadas para obtenção dos parâmetros de transporte do nitrato (utilizando-se o FIA Flow Injection Analysis, para as análises químicas) e potássio (Fotômetro de chama, para as análises químicas). Diante dos resultados obtidos, observou-se que as concentrações do íon nitrato apresentaram variação no solo, encontrando-se valores entre 3,6 a 119 mg L-1, no solo arenoso, e entre 1 e 70 mg L-1, no solo argiloso. Em relação ao potássio foram encontrados valores pontuais de 4,4 a 171,2 mg L-1, no solo arenoso (principalmente na profundidade de 60 cm), e entre 0 e 30 mg L-1, no solo argiloso. As concentrações de cálcio apresentaram variação no solo, sendo encontrados valores pontuais de 1,98 a 64,45 mg L-1, no solo arenoso, e entre 2,6 e 86,5 mg L-1, no solo argiloso. Os valores tanto do pH quando da C.E apresentaram variações no solo, tendo um intervalo para o pH de 6,4 a 7,75 para o solo arenoso e de 4,8 a 7,32 para o solo argiloso e a condutividade elétrica ficou em torno de 0,3 a 2,3 dS m-1 para o solo arenoso e de 0,23 a 0,75 dS m-1 para o solo argiloso. Em relação à curva de distribuição de efluentes da vinhaça, no solo argiloso, observou-se que tanto o potássio quanto o nitrato houve um maior deslocamento das curvas de eluição para a direita quando comparados com o solo arenoso indicando que os íons potássio e nitrato foram retidos com maior intensidade no argiloso em relação ao arenoso. Portanto, concluiu-se que: a percolação dos íons está diretamente relacionada com o tipo de solo e com a concentração de vinhaça e que a movimentação dos íons deve ser estudada em longos períodos para mostrar melhor a sua movimentação no perfil do solo. / While sugarcane has been one of the main crops in Brazilian agriculture since the time of colonization, it is now also a major source of biomass energy, serving sugarcane agribusiness and being responsible for many direct and indirect jobs in Brazil. Industrial processing of sugarcane leads to such products as sugar, alcohol (both hydrated and anhydrated), pulp and vinasse. One concern about the application of vinasse to agricultural operations relates to possible environmental impacts of vinasse. Hence, the present research had as objective to monitor of the dynamics, in different soil types, of chemical components present in vinasse, and to measure breakthrough curves (BTC´s) of vinasse from repacked columns. The research was carried out at the experimental facility of the Department of Exact Sciences, ESALQ, USP, a protected environment containing 50 boxes arranged in a random manner. The vinasse was collected at the Usina Costa Pinto COSAN site in the municipal district of Piracicaba, SP, and applied at rates of 100, 150, 200, 250 and 300 m³ ha-1. The analyzed elements were nitrate and potassium, but measurements were also made of pH, electric conductivity and calcium. The BTC´s were used to provide estimates of the transport parameters of nitrate (using flow-injection analysis for the chemical analyses) and potassium (using a photometer for the chemical analyses). The measurements showed that soil nitrate concentrations varied between 3,6 to 119 mg L-1 in the sandy soil, and between 1 and 70 mg L-1 in the clay soil. Observed potassium concentrations were between 4,4 to 171,2 mg L-1 in the sandy soil (mainly at a depth of 60 cm), and between 0 and 30 mg L-1 in the clay soil. Calcium concentrations were found to similarly vary from 1,98 to 64,45 mg L-1 in the sandy soil, and between 2,6 and 86,5 mg L-1 in the clay soil. The values of pH furthermore varied between 6,4 to 7,75 for the sandy soil and between 4,8 to 7,32 for the clay soil, while the electric conductivity was between 0,3 to 2,3 dS m-1 for the sandy soil and between 0,23 to 0,75 dS m-1 for the clay soil. The vinasse BTC´s of the clay soil showed that both potassium and nitrate were displaced considerably to the right (to higher pore volumes) as compared with the sandy soil. This indicates that the potassium and nitrate ions were kept (adsorbed) much stronger by the clay relative to the sandy soil. Ion transport rates hence were found to be a function of soil type. Results suggest that the transport of ions from the vinasse is best studied over relatively long periods of time, also in field soil profiles, to better show the long-term dynamics in the subsurface
4

Monitoramento de componentes químicos da vinhaça aplicados em diferentes tipos de solo / Monitoring the fate and transport of vinasse chemical components applied to different soil types

João Alberto Lelis Neto 02 February 2009 (has links)
Desde a época da colonização, a cana-de-açúcar apresenta-se como um dos principais produtos da agricultura brasileira e, além disso, trata-se de um tipo importante de biomassa energética, servindo como base para todo o agronegócio sucroalcooleiro, responsável por empregos diretos e indiretos em todo o Brasil. Do seu processo de industrialização são obtidos produtos, tais como: o açúcar, o álcool (anidro e hidratado), o bagaço e a vinhaça. Nesse sentido, diante do aspecto da aplicação da vinhaça em práticas agrícolas, pode-se dizer que sempre ocorre a sua associação com processos de impactos ambientais. Assim sendo, conduziu-se a presente pesquisa buscando-se monitorar a dinâmica, em diferentes tipos de solo, de componentes químicos presentes na vinhaça, bem como, elaborar curvas de distribuição de efluentes presentes na vinhaça. A pesquisa foi conduzida em área experimental do Departamento de Ciências Exatas da ESALQ/USP, em casa de vegetação, onde foram distribuídas 50 bombonas, em blocos casualizados. A vinhaça foi coletada na Usina Costa Pinto do grupo COSAN no município de Piracicaba/SP e as dosagens de aplicação foram: 100 m³ ha-1; 150 m³ ha-1; 200 m³ ha-1; 250 m³ ha-1 e 300 m³ ha-1. As espécies analisadas foram: nitrato e potássio, assim como, o pH, condutividade elétrica e cálcio. As curvas de distribuição de efluentes foram confeccionadas para obtenção dos parâmetros de transporte do nitrato (utilizando-se o FIA Flow Injection Analysis, para as análises químicas) e potássio (Fotômetro de chama, para as análises químicas). Diante dos resultados obtidos, observou-se que as concentrações do íon nitrato apresentaram variação no solo, encontrando-se valores entre 3,6 a 119 mg L-1, no solo arenoso, e entre 1 e 70 mg L-1, no solo argiloso. Em relação ao potássio foram encontrados valores pontuais de 4,4 a 171,2 mg L-1, no solo arenoso (principalmente na profundidade de 60 cm), e entre 0 e 30 mg L-1, no solo argiloso. As concentrações de cálcio apresentaram variação no solo, sendo encontrados valores pontuais de 1,98 a 64,45 mg L-1, no solo arenoso, e entre 2,6 e 86,5 mg L-1, no solo argiloso. Os valores tanto do pH quando da C.E apresentaram variações no solo, tendo um intervalo para o pH de 6,4 a 7,75 para o solo arenoso e de 4,8 a 7,32 para o solo argiloso e a condutividade elétrica ficou em torno de 0,3 a 2,3 dS m-1 para o solo arenoso e de 0,23 a 0,75 dS m-1 para o solo argiloso. Em relação à curva de distribuição de efluentes da vinhaça, no solo argiloso, observou-se que tanto o potássio quanto o nitrato houve um maior deslocamento das curvas de eluição para a direita quando comparados com o solo arenoso indicando que os íons potássio e nitrato foram retidos com maior intensidade no argiloso em relação ao arenoso. Portanto, concluiu-se que: a percolação dos íons está diretamente relacionada com o tipo de solo e com a concentração de vinhaça e que a movimentação dos íons deve ser estudada em longos períodos para mostrar melhor a sua movimentação no perfil do solo. / While sugarcane has been one of the main crops in Brazilian agriculture since the time of colonization, it is now also a major source of biomass energy, serving sugarcane agribusiness and being responsible for many direct and indirect jobs in Brazil. Industrial processing of sugarcane leads to such products as sugar, alcohol (both hydrated and anhydrated), pulp and vinasse. One concern about the application of vinasse to agricultural operations relates to possible environmental impacts of vinasse. Hence, the present research had as objective to monitor of the dynamics, in different soil types, of chemical components present in vinasse, and to measure breakthrough curves (BTC´s) of vinasse from repacked columns. The research was carried out at the experimental facility of the Department of Exact Sciences, ESALQ, USP, a protected environment containing 50 boxes arranged in a random manner. The vinasse was collected at the Usina Costa Pinto COSAN site in the municipal district of Piracicaba, SP, and applied at rates of 100, 150, 200, 250 and 300 m³ ha-1. The analyzed elements were nitrate and potassium, but measurements were also made of pH, electric conductivity and calcium. The BTC´s were used to provide estimates of the transport parameters of nitrate (using flow-injection analysis for the chemical analyses) and potassium (using a photometer for the chemical analyses). The measurements showed that soil nitrate concentrations varied between 3,6 to 119 mg L-1 in the sandy soil, and between 1 and 70 mg L-1 in the clay soil. Observed potassium concentrations were between 4,4 to 171,2 mg L-1 in the sandy soil (mainly at a depth of 60 cm), and between 0 and 30 mg L-1 in the clay soil. Calcium concentrations were found to similarly vary from 1,98 to 64,45 mg L-1 in the sandy soil, and between 2,6 and 86,5 mg L-1 in the clay soil. The values of pH furthermore varied between 6,4 to 7,75 for the sandy soil and between 4,8 to 7,32 for the clay soil, while the electric conductivity was between 0,3 to 2,3 dS m-1 for the sandy soil and between 0,23 to 0,75 dS m-1 for the clay soil. The vinasse BTC´s of the clay soil showed that both potassium and nitrate were displaced considerably to the right (to higher pore volumes) as compared with the sandy soil. This indicates that the potassium and nitrate ions were kept (adsorbed) much stronger by the clay relative to the sandy soil. Ion transport rates hence were found to be a function of soil type. Results suggest that the transport of ions from the vinasse is best studied over relatively long periods of time, also in field soil profiles, to better show the long-term dynamics in the subsurface
5

Acurácia do diagnóstico nutricional do nitrogênio, fósforo e boro para algodoeiro /

Traspadini, Edilaine Istéfani Franklin. January 2019 (has links)
Orientador: Renato de Melo Prado / Resumo: Os valores de referências dos teores de nutrientes foliares de nitrogênio (N), fósforo (P) e boro (B) obtidos por métodos uni, bi e multivariados são publicados sem ter a sua eficiência comprovada. Sendo importante usar o teste de acurácia (APD) de forma integrada para se realizar os ajustes necessários na metodologia para melhorar a eficiência dos diagnósticos, mas isso ainda não é conhecido para cultura do algodão. Diante disso, objetivou-se usar o método APD para disponibilizar valores de referência, pelo método Distribuição Normal Reduzida (DNR), Chance Matemática (CHMAT), Sistema Integrado de Diagnose e Recomendação (DRIS) e Diagnose da Composição Nutricional (CND), eficientes para a diagnose nutricional de N, P e B da cultura do algodão, em Chapadão do Sul - MS. Para obter os valores de referência foram amostradas 144 lavouras comerciais de algodão do município de Chapadão do Sul - MS. No diagnóstico nutricional do DRIS e CND foram usados os fatores 0,5 e 1,0 para ajustar o Índice de balanço Nutricional médio (IBNm). Na mesma região foram realizados três experimentos de calibração, constituídos de quatro doses para cada nutriente (N, P e B), com cinco repetições. Os experimentos foram utilizados para confrontar o diagnóstico obtido pelo método da DNR, CHMAT, DRIS e CND com o Verdadeiro Estado Nutricional (VEN) da planta. O VEN da planta foi definido como deficiente quando a planta apresentava Incremento Real na Produtividade (IRP) acima de 5%, ou 10%, e como suficiente ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The leaf nutrient content of nitrogen (N), phosphorus (P) and boron (B) reference values are reproduced by uni, bi and multivariate methods are published without their proven efficacy. It is important to use the accuracy test (APD) in an integrated manner to make the necessary adjustments to the methodology to improve diagnostic efficiency, but this is not yet known for cotton cultivation. Thus, we aim to use the APD method to provide efficient reference values, the Normal Reduced Distribution (DNR), Mathematical Chance (CHMAT), Integrated Diagnostic and Recommendation System (DRIS) and Diagnostic Nutritional Composition (CND) method. nutritional status of cotton crop N, P and B, in Chapadão do Sul - MS. To obtain the reference values, 144 commercial cotton crops in Chapadão do Sul - MS were sampled. No nutritional diagnosis of DRIS and CND was used by factors 0.5 and 1.0 to adjust the mean nutritional balance index (IBNm). In the same region, three calibration experiments were performed, consisting of four doses for each nutrient (N, P and B), with five replications. The experiments were used to compare or diagnose DNR, CHMAT, DRIS and CND methods with the plant's True Nutritional Status (VEN). Plant VEN was defined as deficient when a plant had a Real Productivity Increase (IRP) above 5%, or 10%, and as sufficient when the increase was lower. The adjustments applied in this study result in an increase of 31%, 98% and 89% for N, P and B, respectively. The CND was the most ef... (Complete abstract click electronic access below) / Doutor
6

Produção e qualidade da variedade local de feijão Gurgutuba em resposta a diferentes adubações / Production and quality of local variety of Gurgutuba beans in response to different fertilizations.

Santos, Emanice Martins dos 29 February 2016 (has links)
Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2016-08-17T15:34:11Z No. of bitstreams: 1 arquivototal.pdf: 3301012 bytes, checksum: 40789967af4dcb4a00a621b3c979ae77 (MD5) / Made available in DSpace on 2016-08-17T15:34:12Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3301012 bytes, checksum: 40789967af4dcb4a00a621b3c979ae77 (MD5) Previous issue date: 2016-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Beans are a food that occupies a notable place in the daily diet of the Brazilian population. Brazil is the second biggest producer and the biggest world consumer per capita of this legume. In the state of Paraíba, beans are the second most produced product, the seeds being of local varieties or creole ones, which are the most cultivated. This research has as its goal the evaluation of the interference of different sources of fertilizers in the characteristics of the production and in the quality of the cultivation of the local purple Gurgutuba bean. This study was conducted in the experimental Field of UFPB (Paraíba Federal University) – Campus III, Bananeiras- PB, in the period of august to december of 2015. The seeds were acquired from a family farming community in Serraria, Paraíba. The experimental outline were in casualized blocks, with seven treatments and four repetitions, totaling twenty eight parcels. The parcels were constituted by three lines of 3 meters, the spacing between the parcels were of 1 meter and spacing between blocks were 2 meters. The productive area was formed by the central line with six plants. The treatments were constituted by: witness treatment (without fertilizer); treatment 1 (bovine manure); treatment 2 (bovine compost); treatment 3 (mineral fertilizer: NPK); treatment 4 (organomineral fertilizer); treatment 5 (goat compost plus organomineral leaf-based fertilizer at 5%) and treatment 6 (goat compost plus leaf-based fertilizer at 10%). Analysis of leaf chlorofil index have been made with ClorofiLOG® model CFL 1030, the measures of gas exchanges were made with Infrared Gas Analyzer – IRGA, components of production, productivity, chemical composition and energetic value of the bean. The data was submitted to the analysis of variance by the test F, and the averages were compared amongst each other by the Tukey test, at 5% of significance. The biggest contents of chlorofil a, b and TL have been observed in the plants of the treatment with bovine compost. The biggest rate of liquid photosynthesis have been observed in the witness treatment, an elevated temperature has been observed in the leaves of the plants of all treatments and an elevated stomatal conductance has been observed with mineral fertilizer. The plants in the treatment with mineral fertilizer were the ones that presented the greatest values of production. In the contents of fiber, lipids, humidity, carbohydrate, ashes and energetic value, differences have been observed. The biggest content of carbohydrate and energetic value were expressed in the grains of the witness treatment. Cultivating Gurgutuba beans submitted to several sources of fertilizers has been shown to have an influence in most of the analyzed aspects, which have evidenced productivities superior to those of the rest of Brazil, Northeast and the state of Paraíba in relation to the year of 2015. / O feijão é um alimento que ocupa um lugar de evidência na alimentação diária da população brasileira. O Brasil é o segundo maior produtor e o maior consumidor mundial per capta dessa leguminosa. No estado da Paraíba, o feijão é o segundo produto mais produzido, sendo as sementes de variedades locais ou crioulas as mais cultivadas. Objetivou-se com a pesquisa avaliar a interferência de diferentes fontes de adubos nas características de produção e na qualidade da cultivar local de feijão Gurgutuba Roxo. O estudo foi conduzido no campo experimental da Universidade Federal da Paraíba – Campus III, Bananeiras-PB, no período de agosto a dezembro de 2015. As sementes foram adquiridas de uma comunidade da agricultura familiar em Serraria-PB. O delineamento experimental foi em Blocos casualizados, com sete tratamentos e quatro repetições, totalizando vinte oito parcelas. As parcelas foram constituídas de três linhas de 3,00 m, o espaçamento entre parcelas foi de 1,00 m e entre blocos de 2,00 m. A área útil foi formada pela linha central com seis plantas. Os tratamentos foram constituídos por: tratamento testemunha (sem adubo); tratamento 1 (esterco bovino); tratamento 2 (composto bovino); tratamento 3 (adubo mineral: NPK); tratamento 4 (adubo organomineral); tratamento 5 (composto caprino mais adubo foliar organomineral a 5%) e tratamento 6 (composto caprino mais adubo foliar organomineral a 10%). Foram realizadas análises de índice de clorofila foliar com o ClorofiLOG® modelo CFL 1030, medidas de trocas gasosas com o Infra-red. Gás Analyzer – IRGA, componentes de produção, produtividade, composição química e valor energético do feijão. Os dados foram submetidos à análise de variância pelo teste F, e as médias foram comparadas entre si pelo teste de Tukey, a 5% de significância. Observou-se os maiores teores de clorofila a, b e TL nas plantas do tratamento com composto bovino. Verificou-se a maior taxa de fotossíntese líquida no tratamento testemunha, uma elevada temperatura foliar nas plantas de todos os tratamentos e uma condutância estomática elevada no tratamento com adubo mineral. As plantas do tratamento com adubo mineral foram as que apresentaram os maiores valores de produção. Nos teores de fibra, lipídeos, umidade, carboidrato, cinzas e valor energético foram observadas diferenças. Os maiores teores de carboidrato e valor energético foram expressos nos grãos do tratamento testemunha. A cultivar Gurgutuba submetida a diversas fontes de adubos foi influenciada na maioria dos parâmetros analisados, os quais evidenciaram produtividades superiores a do Brasil, Nordeste e Paraíba no ano de 2015.

Page generated in 0.0923 seconds