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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.
611

Réalisation d'éco-ciments par la valorisation de cendres volantes de charbon non conventionnelles issues de centrales thermiques Spreader Stoker / Realization of eco-cements using non-conventional coal fly ash from spreader stoker thermal power plants

Sow, Moustapha 06 December 2016 (has links)
L'objectif principal de cette thèse a été d'évaluer le potentiel de valorisation des cendres volantes de charbon issues de centrales thermiques Spreader Stoker (Cendres Volantes Spreader Stoker), dans la fabrication d'éco-ciments sur l'île de La Réunion. Nous avons dans un premier temps effectué une caractérisation physico-chimique des CVSS et vérifié leur réactivité. Deux voies de valorisation ont ensuite été retenues, l'une qui ne présente pas de valeur ajoutée mais qui permet de valoriser un volume important de CVSS par une stabilisation dans des matrices à base de ciment, l'autre qui offre une valeur ajoutée aux CVSS par une incorporation dans la fabrication de ciments composés. Le relargage en lixiviation a été étudié pour la première voie de valorisation retenue, puis, les effets des CVSS dans les matrices à base de ciment, notamment le rôle des imbrûlés contenus dans les cendres, ont été évalués aux états frais, durcissant et durci, suivi d'une petite exploitation numérique des données expérimentales. Enfin, une étude de durabilité sur des bétons à base de ciments de laboratoire a été faite par une approche comparative avec la pouzzolane naturelle, qui est actuellement utilisée pour la fabrication de ciments composés sur l'île de la Réunion. / The main objective of this project was to evaluate the potential of coal fly ash from Spreader Stoker thermal power plants (Spreader Stoker Coal Fly Ash) in the manufacture of eco-cements in Reunion Island. We first performed a physico-chemical characterization SSCFA and verified its reactivity. Two valorisation paths were chosen, one of which did not present any added value but which permit to value a large quantity of SSCFA by stabilization in cement-based matrices, the other which offers added value to SSCFA by incorporating it in the manufacture of composed cements. Leachate release was studied for the first path of valorisation, and then the effects of SSCFA in the cement matrices, especially the unburned particles contained in SSFCA, were evaluated in fresh, hardening and hardened states, followed by a small numerical exploitation of the experimental data. Finally, a sustainability study on concretes based on laboratory cements was made using a comparative approach with natural pozzolana, which is currently used for the manufacture of composite cements in Réunion Island.
612

Misturas de cinza volante e cal de carbureto : comportamento da resistência à compressão simples frente à moagem da cinza volante

Paula, Thaís Martins de January 2016 (has links)
O emprego de resíduos da indústria como materiais alternativos na Engenharia vem sendo tópico recorrente em pesquisas de desenvolvimento de novos materiais, devido a uma maior consciência da opinião pública quanto ao impacto ambiental oriundo da produção industrial. Buscando colaborar com esta discussão, esta pesquisa procurou inserir dois resíduos (cinza volante e cal de carbureto), gerados na região metropolitana de Porto Alegre, como alternativa de solução em Engenharia. Analisando-se a microestrutura da cinza volante, observa-se que ela é formada por esferas ocas e plerosferas (esferas ocas preenchidas por esferas menores). Foi estudado o ganho de resistência da mistura promovido pela moagem da cinza volante em um moinho de bolas cerâmicas, visando uma potencialização da reatividade do material. A fim de possibilitar a utilização destes resíduos, é necessário um estudo do seu comportamento mecânico decorrente da cimentação proporcionada pela mistura e compactação destes materiais. A presente pesquisa busca fornecer subsídios para que seja possível determinar o seu comportamento, através do uso da relação porosidade (η)/teor volumétrico de cal (LV) obtidas a partir da identificação e quantificação das variáveis mais importantes no controle da resistência da mistura dos dois resíduos, com e sem o processo de moagem da cinza, levando a formulação de equações para previsão da resistência à compressão simples do material cimentado para cinza volante com diferentes tempos de moagem e cura acelerada. Para isso, foram realizados ensaios de compressão simples em corpos de prova com 5, 10 e 15% de cal, com peso específico aparente seco de 11, 12 e 13 kN/m3, curados por 7 dias, com umidade de 18% para os tempos de moagem 0, 2 e 6h nas temperaturas 23 e 40°C, e 0 e 6h a 60°C. Os resultados apontam que o aumento do teor de cal gerou ganhos de resistência para as maiores temperaturas de cura; a diminuição da porosidade proporcionou um ganho de resistência para todas as combinações; o aumento da temperatura foi importante no ganho de resistência entre 23oC e 40oC; a moagem da cinza por 2h promoveu ganhos significativos de resistência em relação à não moída, porém, para 6h de moagem os ganhos não foram significativos para as temperaturas de cura de 23oC e 60oC. A relação η/LV, ajustada por um expoente [η/(Lv)0,07], mostrou-se adequada na formulação de equações na previsão da resistência do material cimentado para todas as temperaturas e tempos de moagem estudados. Além disso, a existência de relações únicas e distintas no controle da resistência à compressão simples em função da porosidade, teor volumétrico de cal, temperatura de cura e tempo de moagem, mostraram-se úteis para formulações de dosagem. Os resultados foram submetidos à análise de variância que comprovou que todos os fatores controláveis escolhidos para o experimento são significativos, assim como todas suas interações. / The use of industry by-products as alternative materials in Engineering has been a recurring topic of research in development of new materials, mainly, due to a larger public conscience regarding the environmental impact of industrial production of waste. Aiming to contribute on this discussion, this research sought to introduce two by-products (fly ash and carbide lime), produced on the metropolitan area of Porto Alegre, as an alternative Engineering solution. Analyzing the microstructure of the fly ash, it is observed that it is composed by void spheres and plerospheres (void spheres filed with smaller ones). Having that in mind, it was studied the admix strength gain promoted by the grinding of de fly ash on a ceramic ball mill, aiming an enhancement of the reactivity of the material. In order to enable the use of these byproducts, it is necessary the study of its mechanical behavior due to the cementation provided by the mixture and compaction of these materials. The current research seeks to provide subsides in order to determine its behavior, through the use of the ratio porosity (η)/ volumetric lime content (LV), obtained from the identification and quantification of the most important variables on the control of the strength of the admixes of both by-products, with or without the process of fly ash grinding. This means, the formulation of equations for the simple compressive strength forecast of the cemented material for the fly ash with different grinding times and accelerated curing temperature. In order to do so, it were realized simple compression tests with 5, 10 and 15% of lime, with a specific dry unit weight of 11, 12 and 13 kN/m3, cured for 7 days, with water content of 18% for the grinding times of 0, 2 and 6h to the curing temperatures of 23 and 40oC, and 0 and 6h to 60oC. The results show that, the increase of lime content provided strength gains for the higher temperatures; the decrease of porosity generated strength gain to all the combinations; the increase in curing temperature was important on the strength gain between 23oC and 40oC; the grinding of fly ash for 2h promoted significant strength gains when compared to the not ground samples, however, for 6h of grinding the strength gain wasn’t significant for the 23oC and 60oC curing temperatures. The η/LV ratio, adjusted by an exponent [η/(LV)0,07], presented itself adequate for the formulation of the equations for the forecast of the strength gain of the cemented material to all the studied temperatures and grinding times. Besides that, the existence of unique and distinct relationships on the control of the simple compression strength depending on the porosity, volumetric lime content, curing temperature and grinding time, have been shown useful for the dosage formulation. The results were submitted to variance analysis, which demonstrated that all the factors chosen on the experiment were significant, as all their interactions.
613

Protiprašná opatření a jejich vliv na biodiverzitu složišť popílku / Anti-dustiness measures and their effect on biodiversity of fly ash deposits

ČERNÁ, Ilona January 2014 (has links)
The thesis presents comparison anti-dustiness measures done on fly-ash deposits for several invertebrate groups colonising those deposits. To prevent dustiness, fly-ash is covered by a soil layer. The thesis compares number and abundance of species of any category of Czech Red List of Endangered Species, and species specialized on sandy biotopes on bare fly-ash, fly-ash patrially covered by a soil layer and fly-ash covered by soil layer completely. The consequence of results is that at least small patches of bare soil are crucial for rare species.
614

MICROESTRUTURA DO COBRIMENTO DE CONCRETOS COM ALTOS TEORES DE ESCÓRIA E CINZA VOLANTE ATIVADAS POR CIMENTO PORTLAND E CAL HIDRATADA / MICROSTRUCTURE OF COVERCRETE CONCRETES WITH HIGH CONTENTS OF SLAG AND FLY ASH ACTIVATED BY PORTLAND CEMENTE AND HYDRATED LIME

Brizola, Rodrigo Matzenbacher 08 March 2007 (has links)
In the history of the concrete structures there was a time in which the mechanical resistance was the most important property for the designers. However due to amount of pathologies in the concrete structures and your respective worn-out amounts in recovery, other feature is being prioritized: the durability. And for environmental reasons as global heating, pollution and the raw materials decrease, the sustentability is prioritized. Aiming at collaborate to these factors these paper has as objective analyzes the microstructure of the covercrete with substitution in mass of 90% of cement for mineral additions. Were researched three types of concretes reference concrete (100%CPV-ARI), concrete with 70%Slag+20%FlyAsh and other similar mixture with addition of 20% of hydrated lime with the intention of partially restoring the hydroxide of calcium consumed by the pozzolanics reactions - named respectively of R, EV and EVC. Aims at, more specifically, to establish the differences microstructures of the covercrete of the prototypes(beams-70x20x15cm), through the tests of combined water, x-ray diffraction and scanning electron microscopy. For comparison effect, compressive strength test were also accomplished in molded cylinders(10x20cm) and cured in humid camera and in the cylinders(10x20cm) extracted of the cured prototypes in environmental conditions after 7 days of humid cure. Were studied three relationships a/ag: 0.40, 0.60 and 0.80 for the concrete R and 0.30, 0.40 and 0.50 for the concretes with additions, obtaining resistance between 20 and 70MPa. The tests of the microstructure were accomplished in the 91 and 300 days, with samples starting from the surface of the prototypes, in layers, in the depths of: 0-1.0cm(C1), 2.0-3.0cm(C2) and 4.5-5.5cm(C3). Evolution of the strength was accompanied in the ages of 28, 91, 182 and 300 days. Results were analyzed in equality of a/ag and compressive strength. For a/ag 0.40 and 0.50, to 28 days of age, in relation to reference concrete, the strength of the concrete EV was 54.0% on average of this, and the concrete EVC it was 68.5%. In the final age of 300 days, the percentile are of 72.5% and 76%. In both tests ages, with the increase of the depth of the layer occurs: decrease in the intruded volume total mercury, decrease in the tenor of combined water for the reference concrete and increment in the concretes with additions, decrease in the intensity of pick of the hydroxide of calcium in the three mixtures, decrease in the intensity of pick of the hydrated silicate for the reference concrete and increment in the concretes with mineral additions. Analysis on scanning electron microscopy showed refinement in the size of the grains, larger compact and uniformity in the mixtures with additions / Na história das estruturas de concreto houve período no qual a resistência mecânica foi a propriedade mais importante para os projetistas. Porém, devido ao surgimento de manifestações patológicas nas estruturas de concreto e seus respectivos montantes gastos em recuperação, outro aspecto também está sendo considerado: a durabilidade. Por motivos ambientais como aquecimento global, poluição e diminuição das matérias-primas, prioriza-se também a sustentabilidade. Visando colaborar com estes fatores o presente trabalho tem como objetivo analisar a microestrutura da camada de cobrimento de concretos com substituição em massa de 90% de cimento Portland por adições minerais. Foram pesquisadas três misturas: concreto de referência (100%CPV-ARI), concreto com 70%Escória+20%CinzaVolante e outra mistura similar com adição de 20% de cal hidratada com o intuito de repor parcialmente o hidróxido de cálcio consumido pelas reações pozolânicas as quais foram nomeadas respectivamente de R, EV e EVC. Objetiva, mais especificamente, estabelecer as diferenças microestruturais da camada de cobrimento de protótipos (vigas 70x20x15cm), através dos ensaios de porosimetria por intrusão de mercúrio, água combinada, difração de raios-X e microscopia eletrônica de varredura. Para efeito de comparação, também foram realizados ensaios de resistência à compressão em corpos-de-prova (10x20cm) moldados e curados em câmara úmida e em testemunhos (10x20cm) extraídos dos protótipos curados em condições ambientais após 7 dias de cura úmida. Foram estudadas três relações a/ag: 0.40, 0.60 e 0.80 para o concreto R e 0.30, 0.40 e 0.50 para os concretos com adições, obtendo resistências entre 20 e 70MPa. Os ensaios da microestrutura foram realizados aos 91 e 300 dias, com amostras a partir da face dos protótipos, em três camadas, nas profundidades: 0-1cm(C1), 2- 3cm(C2) e 4.5-5.5cm(C3). A evolução da resistência foi acompanhada nas idades de 28, 91, 182 e 300 dias. Os resultados foram analisados em igualdade de relação a/ag e resistência à compressão. Para as relações a/ag 0.40 e 0.50, aos 28 dias de idade, em relação ao concreto de referência, a resistência do concreto EV foi em média 54.0% deste, e o concreto EVC foi 68.5%. E na idade final de 300 dias, os percentuais são de 72.5% e 76%. Em ambas as idades de ensaio, com o aumento da profundidade da camada ocorreu: decréscimo no volume total intrudido de mercúrio, decréscimo no teor de água combinada para o concreto de referência e acréscimo nos concretos com adições, decréscimo na intensidade de pico do hidróxido de cálcio nas três misturas, decréscimo na intensidade de pico do silicato de cálcio hidratado para o concreto de referência e acréscimo nos concretos com adições minerais. A análise das micrografias mostrou refinamento no tamanho dos grãos, maior densificação e uniformidade nas misturas com adições
615

Avaliação ecotoxicológica dos percolados das colunas de cinza de carvão e de solos com cinza de carvão utilizando Lactuca sativa e Daphnia similis como organismos teste / Ecotoxicological evaluation of leachates from columns of coal fly ash soil with coal fly ash using Lactuca sativa and Daphnia similis as test corganism

CASTRO, FLAVIA J. de 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:41:24Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:39Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
616

Adsorcao de corantes anionicos de solucao aquosa em cinza de carvao e zeolita de cinza leve de carvao / Adsorption of anionic dyes from aqueous solutions onto coal fly ash and zeolite synthesized from coal fly ash

CARVALHO, TEREZINHA E.M. de 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:27:47Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:53Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
617

Efeito do fruto hospedeiro na biologia de Anastrepha fraterculus (Wiedemann, 1830)(Diptera: Tephritidae) e no parasitismo de Diachasmimorpha longicaudata (Ashmead)(Hymenoptera: Braconidae) / Effect of host fruit in Anastrepha fraterculus (Wiedemann, 1830)(Diptera: Tephritidae), and paresitism by Diachasmimorpha longicaudata (Ashmead)(Hymenoptera: Braconidae)

Souza, Ricardo Boldo de 26 August 2015 (has links)
Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-02-21T12:56:01Z No. of bitstreams: 1 PGPV15MA183.pdf: 451845 bytes, checksum: c7c1bdb79011956b4c8a951fea4e5aa8 (MD5) / Made available in DSpace on 2018-02-21T12:56:01Z (GMT). No. of bitstreams: 1 PGPV15MA183.pdf: 451845 bytes, checksum: c7c1bdb79011956b4c8a951fea4e5aa8 (MD5) Previous issue date: 2015-08-26 / The objective of this study was to evaluate, under controlled conditions, the biological parameters of Anastrepha fraterculus in fruits of Campomanesia xanthocarpa (Berg.), cherry of rio grande (Eugenia involucrata DC.) And apple (Malus domestica) Gala variety and parameters morphological, biological and parasitism capacity D. longicaudata in larvae of A. fraterculus in fruits of C. xanthocarpa (Berg.), guava (Feijoa sellowiana Berg.), strawberry guava (Psidium cattleianum), Apple ( Malus domestica) Gala variety and peach (Prunus persica cv. Chimarrita). Before starting the experiment, green fruit C. xanthocarpa and the cherry of rio grande, were protected with TNT fabric bags to prevent oviposition of native flies. For apples were used without fruit of insecticides, kept in cold storage. The fruit maturation period were collected 200, 200 and 100 fruits of, C. xanthocarpa, cherry of rio grande and apple and placed in cages to infestation by A. fraterculus. Then these fruits were weighed individually stored in plastic pots with vermiculite, covered with fabric type voile and maintained in a room at 25 ± 1 C, 70 ± 10% RH and 14 hours photophase. The obtained pupae were weighed and isolated until the emergence of adults. After emergence, 25 couples each host were separated, and these individual cage formed by transparent plastic cup of 250 ml, whose top was covered with tissue type voile. At the top of each cage was placed a “oviposition panel” 7 cm in diameter made from rubberized fabric type voile with black silicone containing distilled water inside for obtaining eggs. For tests with D. longicaudata, fruits were protected with fabric bags TNT, picked in their respective ripening periods and taken to the laboratory to be infested by A. fraterculus. For C. xanthocarpa and strawberry guava they were infested 20 fruits of each species by repetition, totaling six repetitions. For the guava were held six repetitions with ten fruits in apple four replications with 20 fruits and peach were six replicates of ten fruits each. After eight to ten days the fruits were exposed to parasitoids in individual cages containing two couples of D. longicaudata per fruit. After this period the fruits were weighed individually stored in cups containing vermiculite, covered with fabric like voile and maintained in a room at 25 ± 1 C, 70 ± 10% RH and 14 hours photophase. The obtained pupae were placed in separate culture plates and subject to emergency flies or parasitoids. After emergence, it was found the size and parasitoid development time and the sex ratio. The percentage of parasitism was calculated by formula: N°. parasitoids / (N° of parasitoids + N°. flies) x 100. In the experiment on the biology of A. fraterculus larvae that developed in apple had the longest period of egg-larva (18.37 days) and egg-adult period (34.74 days). To adult stage, it was observed that the insects created in the cherry of rio grande and apple showed higher oviposition period, since the insects coming from C. xanthocarpa posted the largest daily fertility, with a rate of oviposition 20.70 eggs per day. Thus we can conclude that A. fraterculus completed all its stages in the evaluated fruits, occurring a delay in larval development in apples as a result of low nutritional value of this fruit as A.fraterculus host. Parasitoids in the percentage of parasitism in C. xanthocarpa, guava, strawberry guava, apple and peach was 88.34%; 87.63%; 69.66%, 71.05% and 34.25% respectively, confirming the good performance of the parasitoid that even though under laboratory conditions females of D. longicaudata inexperienced with fruit, were able to locate and parasitize fly larvae -the fruit. The size of the parasitoids was higher in A. fraterculus larvae that developed in C. xanthocarpa and peach. The parasitoids coming from C. xanthocarpa larvae showed the lowest development time for males (17.96 days) and females (20.94 days). Have low sex ratio, found in D. longicaudata female, coming from larvae of A. fraterculus that developed in guava and strawberry guava, may have association with the high percentage of unviable pupae, obtained in these hosts / O objetivo do presente trabalho foi avaliar, em condições controladas, os parâmetros biológicos de Anastrepha fraterculus em frutos de Cereja do rio grande (Eugenia involucrata DC.), Guabiroba (Campomanesia xanthocarpa Berg.) e Maçã (Malus domestica variedade Gala), a capacidade de parasitismo, os parâmetros biológicos e morfológicos de D. longicaudata em larvas de A. fraterculus em frutos de guabiroba (C. xanthocarpa Berg.), araçá-vermelho (Psidium cattleianum), goiaba-serrana (Feijoa sellowiana Berg.), pêssego (Prunus persica cv. Chimarrita) e Maçã (Malus domestica variedade Gala). Antes do início do experimento, os frutos verdes de guabiroba e cereja do rio grande, foram protegidos com sacos de tecido TNT para evitar a oviposição de moscas nativas. Para as maçãs foram utilizados frutos sem resíduo de inseticidas, mantidos em câmara fria. Na época de maturação dos frutos foram coletados 200, 200 e 100 frutos, de guabiroba, cereja do rio grande e maçã e acondicionados em gaiolas para infestação por A. fraterculus. Em seguida esses frutos foram pesados, armazenados individualmente em potes plásticos com vermiculita, cobertos com tecido tipo voile e mantidos em sala climatizada a 25±1 C, 70±10% de UR e 14 horas de fotofase. As pupas obtidas foram pesadas e individualizadas até a emergência dos adultos. Após a emergência, foram separados 25 casais de cada hospedeiro, sendo esses individualizados em gaiola formada por copo plástico transparente de 250 mL, cuja parte superior foi coberta com tecido tipo voile. Na parte superior de cada gaiola foi colocado um “painel de oviposição” de 7 cm de diâmetro confeccionado com tecido tipo voile emborrachado com silicone preto contendo água destilada em seu interior para a obtenção de ovos. Para os testes com D. longicaudata os frutos foram protegidos com sacos de tecido TNT, colhidos nas suas respectivas épocas de maturação e levados para o laboratório para serem infestados por A. fraterculus. Para a guabiroba e araçá-vermelho foram infestados 20 frutos de cada espécie por repetição, totalizando seis repetições. Para a goiaba-serrana foram realizadas seis repetições com dez frutos, em maçã quatro repetições com 20 frutos e para o pêssego foram seis repetições com dez frutos cada. Após oito a dez dias os frutos foram expostos aos parasitoides em gaiolas individualizadas contendo dois casais de D. longicaudata por fruto. Após esse período os frutos foram armazenados individualmente em copos, contendo vermiculita, cobertos com tecido tipo voile e mantidos em sala climatizada a 25±1 C, 70±10% de UR e 14 horas de fotofase. As pupas obtidas foram individualizadas em placas de cultura e observadas até a emergência de moscas ou parasitoides. Após a emergência, era verificado o tamanho e o tempo de desenvolvimento do parasitoide e a razão sexual. A porcentagem de parasitismo foi calculada pela formula: n° de parasitoides / (n° de parasitoides + n° de moscas) x 100. No experimento sobre a biologia de A. fraterculus, as larvas que se desenvolveram na maçã apresentaram o maior período de ovolarva (18,37 dias) e período de ovo-adulto (34,74 dias). Para a fase adulta, foi observado que os insetos que criados em cereja do rio grande e maçã apresentaram maior período de oviposição, já os insetos oriundos da guabiroba apresentaram a maior fecundidade diária, com um ritmo de oviposição de 20,70 ovos por dia. Desta forma podemos concluir que A. fraterculus completou todas as suas fases nos frutos avaliados, ocorrendo um atraso no desenvolvimento larval em maçãs, resultado da baixa qualidade nutricional desse fruto como hospedeiro de A. fraterculus. Nos parasitoides a porcentagem de parasitismo em guabiroba, araçá-vermelho, goiaba-serrana, maçã e pêssego foi de 88,34%; 87,63%; 69,66%, 71,05% e 34,25% respectivamente, constatando a ótima performance do parasitoide que mesmo sendo em condições de laboratório as fêmeas de D. longicaudata sem experiência prévia com frutos, foram capazes de localizar e parasitar as larvas de mosca-dasfrutas. O tamanho dos parasitoides foi maior em larvas de A. fraterculus que se desenvolveram em guabiroba e pêssego. Os parasitoides oriundos de larvas da guabiroba apresentaram o menor tempo de desenvolvimento para machos (17,96 dias) e fêmeas (20,94 dias). Já a baixa razão sexual, encontrada em fêmeas de D. longicaudata, oriundas de larvas de A. fraterculus que se desenvolveram no araçá-vermelho e na goiaba-serrana, pode ter associação com a alta porcentagem de pupas inviáveis, obtida nesses hospedeiros
618

Caracterização do manejo de pragas empregado pelos produtores de uva de mesa Itália sob plástico / Characterization of pest management in Italia table grapes under plastic cover

Formolo, Rodrigo 24 March 2010 (has links)
Made available in DSpace on 2016-12-08T16:44:35Z (GMT). No. of bitstreams: 1 PGPV10MA053.pdf: 1403790 bytes, checksum: fcc8683e96f4b0f7306c0fe41c66ad8f (MD5) Previous issue date: 2010-03-24 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Production of grapes for processing is one of the most important agricultural activities in Caxias do Sul municipality, Rio Grande do Sul State. In recent years, however, growers in the municipality are installing new vineyards for table grape production (Vitis vinifera) using plastic cover. Few information is available in relation to this production system mainly in relation to insect and mite management. This work was carried out to know the area grown with table grapes under plastic cover in the municipality, to identify the most damaging phytophagous and mite species in the vineyards and pest management adopted by growers, to monitor south American fruit fly Anastrepha fraterculus adults in the vineyards along the season and to know the effect of insecticides to control the specie in plastic cover vineyards. We identify 43 growers producing table grape under plastic cover in a total of 303.650 m2 ha in Caxias do Sul. The most important cultivar grown under plastic cover is Italia which is responsible for 70,31% of the total area grown. The most damaging insect pests for Italia table grape in the region are the flower thrips Frankliniella rodeos Moulton and the south american fruit fly Anastrepha fraterculus (Wiedemann, 1830). Insecticide application in a calendar base is the principal strategy used for grape growers for insect pest management in the vineyards. The monitoring of south american fruit fly using McPhail traps baited with hydrolyzed protein showed a higher incidence during the maturation period. Vineyards located near hosts suitable for fruit fly development and without insect control showed higher levels of infestation. A maximum of 16% of berries damaged by fruit fly were observed. Fenthion was a high efficient insecticide to control adult and larvae of fruit flies while a commercial rotenone and nim based insecticide (Rot-Nim) was effective only for adults but not for larvae of A. fraterculus. / O cultivo da videira para processamento é uma das principais atividades econômicas agrícolas do município de Caxias do Sul, no Rio Grande do Sul. No entanto, recentemente vários produtores tem implantado vinhedos de uvas finas de mesa (Vitis vinifera L.) sob plástico. Poucas informações estão disponíveis sobre este sistema de produção principalmente em relação ao manejo de pragas. Este trabalho foi realizado com o objetivo de conhecer a área cultivada com uvas finas de mesa sob plástico no Município, identificar as principais pragas e as estratégias de manejo empregadas pelos produtores, avaliar a flutuação populacional de adultos de Anastrepha fraterculus em uva fina de mesa e o efeito de inseticidas a campo e em laboratório para o controle da espécie em cultivo protegido. Através de entrevistas a todos produtores de uva de mesa produzida sob cobertura plástica do município foram identificadas 43 propriedades, sendo que a cultivar mais produzida é a Itália com 70,31% da área total de 303.650 m2. As principais pragas prejudiciais ao cultivo mencionadas pelos produtores foram o tripes Frankliniella rodeos Moulton e a mosca da fruta sulamericana Anastrepha fraterculus (Wiedemann, 1830), sendo que a aplicação de inseticida por calendário é a principal forma de controle de insetos na cultura. Utilizando armadilhas modelo McPhail, iscadas com proteína hidrolisada (BioAnastrepha® a 5%), instaladas em 6 vinhedos, foi observado que picos de adultos de A. fraterculus coincidem com a maturação e colheita dos frutos. Vinhedos que apresentam hospedeiros alternativos e multiplicadores de A. fraterculus no seu entorno são áreas mais propícias à ocorrência e quando não tomadas medidas de controle, perdas significativas da produção (até 16%) foram registradas. A campo e em laboratório, o inseticida fentiona foi eficaz no controle de adultos e larvas sendo que o composto à base de rotenona e nim (Rot-Nim) apresentou efeito sobre adultos não sendo indicado para o controle de larvas de A. fraterculus
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Synthesis of zeolites from South African coal fly ash: investigation of scale-up conditions

Mainganye, Dakalo January 2012 (has links)
Thesis submitted in fulfilment of requirements for the degree Magister Technologiae: Chemical Engineering In the FACULTY OF ENGINEERING At the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY, 2012 / The generation of electricity from coal in South Africa results in millions of tons of fly ash being produced each year. Less than 10 % of the fly ash generated is being used constructively and the remaining unused ash is currently inducing disposal and environmental problems. Intensive research on the utilisation of fly ash has been conducted either to reduce the cost of disposal or to minimise its impact on the environment. It has been shown that South African fly ash can be used as a feedstock for zeolite synthesis due to its compositional dominance of aluminosilicate and silicate phases. Most of the studies conducted on zeolite synthesis using South African fly ash are performed on small laboratory scale. Therefore, production of zeolites on an industrial/pilot plant scale would, in addition to producing a valuable product, help abate the pollution caused by the disposal of fly ash in the country. This research focuses on the investigation of the scale-up opportunity of zeolite synthesis from South African fly ashes with the view of understanding the effects of some reactor and operational parameters on the quality of the zeolite produced. Two types of zeolites (zeolite Na-P1 and zeolite A) were synthesised via two different routes in this study: (1) a two stage hydrothermal synthesis method (zeolite Na-P1) and (2) alkaline fusion prior to hydrothermal synthesis (zeolite A). The synthesis variables evaluated in this study were; the effect of impeller design and agitation rates during the aging step (zeolite Na-P1) using three different impellers (anchor, 4-flat-blade and Archimedes screw impeller) at three agitation speeds (150, 200 and 300 rpm), the effect of fly ash composition and solvents (water sources) on the phase purity of both zeolite Na-P1 and zeolite A, and the effect of the hydrothermal reaction time during the synthesis of zeolite Na-P1 using low amorphous phase fly ash i.e. aging time (12-48 hours) and hydrothermal treatment time (12-48 hours). The raw materials (fly ashes from Arnot, Hendrina, Tutuka, Lethabo and Matla power stations) and the synthesised zeolite product were characterised chemically, mineralogically and morphologically by X-ray fluorescence spectrometry, X-ray powder diffraction and scanning electron microscopy. Other characterisation techniques used in the study were 1) Fourier transform infrared spectroscopy to provide structural information and also monitor the evolution of the zeolite crystals during synthesis and 2) inductively coupled plasma atomic emission (ICP-AES) and mass spectrometry for multi-elemental analysis of the synthesis solution and the solvents used in this study. The experimental results demonstrated that the phase purity of zeolite Na-P1 was strongly affected by agitation and the type of impeller used during the aging step of the synthesis process. A high crystalline zeolite Na-P1 was obtained with a 4-flat-blade impeller at a low agitation rate of 200 rpm. Although a pure phase of zeolite Na-P1 was obtained at low agitation rates, the variation in the mineralogy of the fly ash was found to affect the quality of the zeolite produced significantly. The results suggested that each batch of fly ash would require a separate optimisation process of the synthesis conditions. Therefore, there is a need to develop a database of the synthesis conditions for zeolite Na-P1 based on the fly ash composition. As a consequence, the scale-up synthesis of zeolite Na-P1 would require step-by-step optimisation of the synthesis conditions, since this zeolite was sensitive to the SiO2/Al2O3 ratio, agitation and the mineralogy of the fly ash. On the other hand, zeolite A synthesis had several advantages over zeolite Na-P1. The results suggested that a pure phase of zeolite A can be produced at very low reaction temperature (i.e. below 100 °C, compared to 140 °C for zeolite Na-P1), shorter reaction times (i.e. less than 8 hours compared to 4 days for zeolite Na-P1), with complete dissolution of fly ash phases and more importantly less sensitive to the SiO2/Al2O3 ratio of the raw materials. The zeolite A synthesis process was found to be more robust and as a result, it would be less rigorous to scale-up despite the energy requirements for fusion. This study showed for the first time that different impeller designs and agitation during the aging step can have a profound impact on the quality of the zeolite produced. Therefore, it is not only the hydrothermal synthesis conditions and the molar regime but also the dissolution kinetics of the feedstock that influence the outcome of the zeolite synthesis process. This study has also shown for the first time that a pure phase of zeolite A can be synthesised from various sources of South African fly ash containing different mineralogical and chemical compositions via the alkali fusion method under the same synthesis conditions. Therefore, the effective zeolitisation of fly ash on a large scale would assist to mitigate the depletion of resources and environmental problems caused by the disposal of fly ash.
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Misturas de cinza volante e cal de carbureto : comportamento da resistência à compressão simples frente à moagem da cinza volante

Paula, Thaís Martins de January 2016 (has links)
O emprego de resíduos da indústria como materiais alternativos na Engenharia vem sendo tópico recorrente em pesquisas de desenvolvimento de novos materiais, devido a uma maior consciência da opinião pública quanto ao impacto ambiental oriundo da produção industrial. Buscando colaborar com esta discussão, esta pesquisa procurou inserir dois resíduos (cinza volante e cal de carbureto), gerados na região metropolitana de Porto Alegre, como alternativa de solução em Engenharia. Analisando-se a microestrutura da cinza volante, observa-se que ela é formada por esferas ocas e plerosferas (esferas ocas preenchidas por esferas menores). Foi estudado o ganho de resistência da mistura promovido pela moagem da cinza volante em um moinho de bolas cerâmicas, visando uma potencialização da reatividade do material. A fim de possibilitar a utilização destes resíduos, é necessário um estudo do seu comportamento mecânico decorrente da cimentação proporcionada pela mistura e compactação destes materiais. A presente pesquisa busca fornecer subsídios para que seja possível determinar o seu comportamento, através do uso da relação porosidade (η)/teor volumétrico de cal (LV) obtidas a partir da identificação e quantificação das variáveis mais importantes no controle da resistência da mistura dos dois resíduos, com e sem o processo de moagem da cinza, levando a formulação de equações para previsão da resistência à compressão simples do material cimentado para cinza volante com diferentes tempos de moagem e cura acelerada. Para isso, foram realizados ensaios de compressão simples em corpos de prova com 5, 10 e 15% de cal, com peso específico aparente seco de 11, 12 e 13 kN/m3, curados por 7 dias, com umidade de 18% para os tempos de moagem 0, 2 e 6h nas temperaturas 23 e 40°C, e 0 e 6h a 60°C. Os resultados apontam que o aumento do teor de cal gerou ganhos de resistência para as maiores temperaturas de cura; a diminuição da porosidade proporcionou um ganho de resistência para todas as combinações; o aumento da temperatura foi importante no ganho de resistência entre 23oC e 40oC; a moagem da cinza por 2h promoveu ganhos significativos de resistência em relação à não moída, porém, para 6h de moagem os ganhos não foram significativos para as temperaturas de cura de 23oC e 60oC. A relação η/LV, ajustada por um expoente [η/(Lv)0,07], mostrou-se adequada na formulação de equações na previsão da resistência do material cimentado para todas as temperaturas e tempos de moagem estudados. Além disso, a existência de relações únicas e distintas no controle da resistência à compressão simples em função da porosidade, teor volumétrico de cal, temperatura de cura e tempo de moagem, mostraram-se úteis para formulações de dosagem. Os resultados foram submetidos à análise de variância que comprovou que todos os fatores controláveis escolhidos para o experimento são significativos, assim como todas suas interações. / The use of industry by-products as alternative materials in Engineering has been a recurring topic of research in development of new materials, mainly, due to a larger public conscience regarding the environmental impact of industrial production of waste. Aiming to contribute on this discussion, this research sought to introduce two by-products (fly ash and carbide lime), produced on the metropolitan area of Porto Alegre, as an alternative Engineering solution. Analyzing the microstructure of the fly ash, it is observed that it is composed by void spheres and plerospheres (void spheres filed with smaller ones). Having that in mind, it was studied the admix strength gain promoted by the grinding of de fly ash on a ceramic ball mill, aiming an enhancement of the reactivity of the material. In order to enable the use of these byproducts, it is necessary the study of its mechanical behavior due to the cementation provided by the mixture and compaction of these materials. The current research seeks to provide subsides in order to determine its behavior, through the use of the ratio porosity (η)/ volumetric lime content (LV), obtained from the identification and quantification of the most important variables on the control of the strength of the admixes of both by-products, with or without the process of fly ash grinding. This means, the formulation of equations for the simple compressive strength forecast of the cemented material for the fly ash with different grinding times and accelerated curing temperature. In order to do so, it were realized simple compression tests with 5, 10 and 15% of lime, with a specific dry unit weight of 11, 12 and 13 kN/m3, cured for 7 days, with water content of 18% for the grinding times of 0, 2 and 6h to the curing temperatures of 23 and 40oC, and 0 and 6h to 60oC. The results show that, the increase of lime content provided strength gains for the higher temperatures; the decrease of porosity generated strength gain to all the combinations; the increase in curing temperature was important on the strength gain between 23oC and 40oC; the grinding of fly ash for 2h promoted significant strength gains when compared to the not ground samples, however, for 6h of grinding the strength gain wasn’t significant for the 23oC and 60oC curing temperatures. The η/LV ratio, adjusted by an exponent [η/(LV)0,07], presented itself adequate for the formulation of the equations for the forecast of the strength gain of the cemented material to all the studied temperatures and grinding times. Besides that, the existence of unique and distinct relationships on the control of the simple compression strength depending on the porosity, volumetric lime content, curing temperature and grinding time, have been shown useful for the dosage formulation. The results were submitted to variance analysis, which demonstrated that all the factors chosen on the experiment were significant, as all their interactions.

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