31 |
AvaliaÃÃo da disponibilidade de nitrogÃnio encapsulado em zeÃlita 4a na fertilizaÃÃo de substrato natural para cultivo de Zea mays / Evaluation of nitrogen availability encapsulated in zeolite 4A in the fertilization of natural substrate for cultivation of Zea maysJardel Cavalcante Rolim de Almeida Andrade 10 August 2009 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / As zeÃlitas sintÃticas apresentam uma sÃrie de vantagens sobre as naturais em diversas aplicaÃÃes. Estudos recentes tÃm demonstrado que as zeÃlitas sÃo mais eficientes que as argilas na capacidade em reter Ãgua e exercer trocas iÃnicas de espÃcies iÃnicas importantes para a agricultura, alÃm de permitir acomodar apreciÃvel quantidade de sais que podem servir como fontes de nitrogÃnio e outros para vegetais. Tendo em vista a importÃncia tecnolÃgica das zeÃlitas, o presente trabalho tem como objetivo sintetizar a zeÃlita 4A, atravÃs de uma nova metodologia baseada na diagÃnese acelerada envolvendo um metacaulim. Neste estudo foram avaliados tambÃm os aspectos quantitativos e termocinÃticos aplicando o modelo de Osawa (estabilidade tÃrmica), do nitrato de amÃnio (NH4 + e NO3 -) ocluido na estrutura de uma zeÃlita 4A, a partir do qual pode vir a simular uma forma de cultivo com nitrogÃnio menos dispendioso. A zeÃlita 4A foi obtida atravÃs de uma nova metodologia baseada na diagÃnese acelerada do metacaulim, com a caracterizaÃÃo dos precursores e produtos por meio de difraÃÃo de raios-X (refinamento pelo MÃtodo de Rietveld).O tratamento tÃrmico para preparaÃÃo da zeÃlita ocluida conduz inevitavelmente à mistura na qual a zeÃlita fica com sua estrutura saturada pelo nitrato de amÃnio. Este sal interage com os vÃrios poros da zeÃlita, de forma que esta caracterÃstica irà estabelecer domÃnio sobre a propriedade de liberaÃÃo, com o emprego de diferentes quantidades de energia, tornando-a controlÃvel e lenta, comportamento desejÃvel para o uso na agricultura. Uma zeÃlita 4A foi sintetizada em escala piloto e usada como carreador de nitrogÃnio. Foram realizadas anÃlises termogravimÃtricas para determinar a relaÃÃo da energia de ativaÃÃo com a massa residual, no qual foram estabelecidos parÃmetros energÃticos para disponibilidade de nitrogÃnio (NH4NO3) no substrato natural para cultivo de milho. A energia de ativaÃÃo para 60% m/m de nitrogÃnio introduzido nos poros da zeÃlita 4A resultou em dois patamares de energia. As caracterÃsticas geoquÃmicas e fÃsico-quÃmicas do solo favorecem seu uso como suporte para a zeÃlita ocluida com NH4NO3. A produÃÃo de matÃria seca no cultivo com diferentes concentraÃÃes de nitrogÃnio ocluido na zeÃlita se mostrou mais eficiente do que o fertilizante tradicional, demonstrando haver melhor aproveitamento de nitrogÃnio com reduÃÃo das perdas por lixiviaÃÃo, mostrando-se a viabilidade de sua aplicaÃÃo como uma alternativa de cultivo eficiente e menos dispendioso a baixas concentraÃÃes de nitrogÃnio. Palavras-chaves: caulim, zeÃlita, oclusÃo, nitrato de amÃnio, milho, Zea mays L. / Synthetic zeolites presented a series of advantages over the natural ones in several applications. Recent works have shown that zeolites are more efficient than clay regarding to their ability to retain water and to allow ionic exchange of important substances for agriculture use as well as to lodge large amounts of salts which can be useful as nitrogen and other compounds source for vegetables. Due to the technological importance of zeolites, this work aims to synthesize 4A zeolite by means of a new methodology based on fast diagenisis involving a metakaolin. This study also evaluates the quantitative and thermokinetic aspects by means of Ozawa method (thermal stability) of the ammonium nitrate (NH4 + and NO3 -) occluded within the 4A zeolite structure, from which one could simulate a new and low-cost way of cultivation. 4A zeolite was obtained by a new methodology based on the fast diagenisis of kaolin, with the characterization of their precursors and products carried out by X-ray diffraction measurements (refined by Rietveld Method). The thermal treatment necessary for the preparation of occluded zeolite gives rise inevitably to a mixture in which the zeolite remains within its structure saturated with ammonium nitrate. This salt interacts with the several pores of the zeolite in such a way that this property will dominate the salt liberation process, by using different amounts of energy and making it to be controllable and slow, which is the desired behaviour for agriculture purposes. A 4A zeolite has been synthesized in pilot scale and it was used as nitrogen carrier. Thermogravimetric analysis were carried out in order to determinate the relationship between the activation energy and residual mass, in which the energetic parameters have been established for the nitrogen in the NH4NO3 form within the natural substrate during the corn cultivation. The activation energy for 60% w/w of the nitrogen introduced in the 4A zeolite pores resulted in two energy platforms. The geochemical and physical-chemical soil characteristics favoured its use as support for the NH4NO3 occluded zeolite. The production of dry matter in the cultivation with different concentrations of the occluded nitrogen turned out to be more efficient than the traditional fertilizers; allowing one to conclude there is a better performance of nitrogen with a reduction of losses by lixiviation so that its application is feasible as an economic form of cultivation, at low nitrogen concentations.
|
32 |
Étude des processus de formation et élimination du N2O lors de la Réduction Catalytique de NOx par le NH3 (NH3-SCR) / Study of the formation and elimination of N2O in the Selective Catalytic Reduction of NOx by NH3 (NH3-SCR)Valdez Lancinha Pereira, Mafalda 15 December 2016 (has links)
Le projet de thèse a eu pour but l’étude de la formation et de l’élimination du N2O par des catalyseurs cuivre-zéolithe ou fer-zéolithe, utilisés pour le procédé de réduction catalytique sélective des NOx par l'ammoniac (NH3-SCR). Dans ce processus de réduction des NOx, les principales voies de formation de N2O sont la décomposition du nitrate d’ammonium (NH4NO3) et l’oxydation de NH3. L’étude bibliographique a montré une contribution plus importante de la décomposition du nitrate d’ammonium. La recherche s’est donc focalisée dans l’étude de la décomposition du nitrate d’ammonium en empruntant deux axes : la décomposition du NH4NO3 commercial et la formation in situ suivi de la décomposition du nitrate d’ammonium.Les catalyseurs, utilisés pour cette étude, ont été, tout d'abord, amplement caractérises par différentes techniques d’analyse physico-chimique afin de connaitre particulièrement la concentration et forme de déposition des métaux, l’acidité et la taille des cristaux.Après avoir abordé la décomposition du NH4NO3 commercial sans catalyseur, l'étude s'est orientée sur l'effet de l'interaction avec un catalyseur. La nature du gaz vecteur, les conditions hydrodynamiques et la quantité de NH4NO3 ont aussi été évaluées.La décomposition sous conditions statiques, i.e. sans entrainement du NH4NO3 liquide, conduit principalement le N2O. En revanche, les chemins réactionnels suivis sous conditions dynamiques dépendent du mode de déposition du nitrate d’ammonium. Les agrégats solides de nitrate d'ammonium en contact avec la surface externe du catalyseur se décomposent directement en N2O, surtout quand le nitrate d’ammonium liquide ne peut pas être entrainé par le gaz vecteur. L’absence de catalyseur favorise la décomposition vers l’azote par l’interaction entre le NH3 et du HNO3 libérés lors de la dissociation du NH4NO3. D’autre part, en présence d’un catalyseur, le NH3 formé tend à s’adsorber et à s’oxyder à plus haute température. La variation du gaz vecteur n'engendre pas d'effet significatif sur la décomposition du NH4NO3.La décomposition du nitrate d’ammonium formé in situ a été réalisée dans le but de se rapprocher des conditions du procédé NH3-SCR, où le nitrate d’ammonium se forme par l’interaction entre le NH3 et le NO2. La méthode expérimentale a été conçue pour maximiser la formation du nitrate d’ammonium selon les deux cas extrêmes pouvant être trouvés dans un système SCR : la saturation préalable du catalyseur en NH3 puis en NO2 (« NH3 experiment ») et l’inverse, saturation en NO2 puis NH3 (« NO2 experiment »). Dans ce cas plusieurs catalyseurs ont été préparés afin d’isoler certaines caractéristiques et évaluer leur impact. Les effets de la teneur en cuivre, du type de métal (Cu ou Fe), de la structure de la zéolite (CHA ou FER), de la méthode de préparation, de l’atmosphère de calcination et du gaz vecteur pendant la décomposition ont été étudiés. Les effets obtenus ont été corrélés avec les résultats de la caractérisation physicochimique des catalyseurs afin de déterminer les paramètres prépondérants des différences observées.La formation du N2O lors du « NH3 experiment » est toujours plus importante que celle obtenue dans le « NO2 experiment » et dépend fortement de la concentration en sites acides de Brönsted quelle que soit la structure de la zéolithe. En revanche, dans le « NO2 experiment », ce sont plutôt les espèces métalliques et sa localisation qui influencent la décomposition du nitrate d’ammonium. La taille des cristaux a aussi une influence. La méthode de préparation et l’atmosphère de calcination n’ont pas un effet très significatif. Le gaz vecteur influence seulement les émissions à haute température : la formation du N2O est plus importante en présence d’oxygène. / The thesis project focused on the study of the formation and elimination of N2O by copper-zeolite or iron-zeolite catalysts, used for selective catalytic reduction of NOx with ammonia (NH3-SCR). In the NOx reduction process the main N2O formation routes are the decomposition of the ammonium nitrate (NH4NO3) and the NH3 oxidation. Still, a literature review showed a more important contribution from the decomposition of ammonium nitrate. Therefore, the study was then concentrated on the decomposition of the ammonium nitrate in two axes: the decomposition of commercial NH4NO3 and the in situ formation followed by decomposition of ammonium nitrate.Besides, the catalysts used for this study, have been thoroughly characterized by different physicochemical techniques in order to, particularly, assess the concentration and deposition form of metals, the acidity and the size of the crystals.After performing the decomposition of commercial NH4NO3 without catalyst, the study has focused on the effect of interaction with a catalyst. The effect of the carrier gas, the hydrodynamic conditions and concentration of NH4NO3 were also studied.Under static conditions, i.e. without liquid NH4NO3 entrainment, the decomposition of the commercial ammonium nitrate mostly leads to N2O. In contrast, the reaction pathway under dynamic conditions depends on the deposition method of ammonium nitrate onto the catalyst. The solid aggregates in the outer surface of the catalyst decompose directly to N2O, especially when the liquid ammonium nitrate cannot be entrained by the carrier gas. The absence of a catalyst promotes the decomposition into nitrogen, formed by the interaction between the NH3 and HNO3 released upon the dissociation of NH4NO3. On the other hand, in the presence of a catalyst NH3 tends to adsorb and to be oxidized at higher temperatures. The carrier gas composition did not have a significant effect in the decomposition of NH4NO3.The decomposition of ammonium nitrate formed in situ was performed in order to get closer from what happens under SCR conditions, where the ammonium nitrate is formed by the interaction between NH3 and NO2. The experimental method was designed to maximize the formation of ammonium nitrate according to the two extreme conditions that may be found in a SCR system: firstly catalyst saturation by NH3 and then by NO2 (“NH3 experiment”) and then the reverse, saturation by NO2 and then by NH3 (“NO2 experiment”). In this study several catalysts were prepared in order to isolate certain characteristics and assess their impact. The effects of the copper loading, the type of metal (Cu and Fe), the structure of the zeolite (CHA or FER), the method of preparation, the calcination atmosphere and the carrier gas during decomposition were studied. These effects were correlated to the results of the physico-chemical characterization of the catalysts with the purpose of find the cause of the faced differences.The formation of N2O during the “NH3 experiment” is always greater than that obtained on the “NO2 experiment”, and strongly depends on the concentration of the Brönsted acid sites, regardless the zeolite structure. However, on the “NO2 experiment”, it is rather the metal species and its location that influence the decomposition of ammonium nitrate. The size of the crystals also has an influence. The preparation method and the calcination atmosphere do not have a significant effect. The carrier gas impacts on the high temperature emission: the formation of N2O is greater in the presence of oxygen.
|
33 |
Analysis of Improvised Explosives by Electrospray Ionization - Mass Spectrometry and Microfluidic TechniquesCorbin, Inge 01 July 2016 (has links)
Improvised explosives may be based on smokeless gunpowder, fertilizers, or inorganic oxidizers such as nitrate (NO3-), chlorate (ClO3-), and perchlorate (ClO4-) salts.
Identification is a priority for the military and law enforcement but due to their varying physical properties and complexity, identification can be challenging. Consequently, three methods have been developed to aid in presumptive and confirmatory detection.
Smokeless powder contains plasticizers, stabilizers, dyes, opacifiers, flash suppressants, and other compounds. Identification of these additives can narrow down or identify the brands of smokeless powder used in a device. Fourteen organic smokeless powder components were identified by capillary electrochromatography (CEC) using a hexyl acrylate monolithic stationary phase coupled to UV detection and time-of-flight mass spectrometry (TOF-MS). The CEC-UV method efficiently detects all 14 organic components, while TOF-MS provides sensitivity and selectivity. A mixed smokeless powder component standard was analyzed and the composition of the additive package in commercial smokeless powders determined. Detection limits ranged from 1.0 – 3.2 μg/ml and analysis time was 18 minutes.
Second, a procedure for the detection of urea nitrate (UN) and ammonium nitrate (AN) by infusion electrospray ionization - mass spectrometry (ESI-MS/MS) was developed. Solubility tests were performed to find a solvent for both UN and AN that did not cause UN to dissociate. Two adduct ions were detected for each explosive: for AN, m/z 178 [2AN+NH4]+ and m/z 258 [3AN+NH4]+ ions, and for UN m/z 185 [UN+NO3]− and m/z 248 [UN+HNO3+NO3]−. Specificity of the analysis was examined by mixing the explosives with various salts and interferents. Gas-phase adduct ions were useful in distinguishing between ion pairs and mixed salts.
Finally, a paper microfluidic device (PMD) was developed as a presumptive test using colorimetric reagents for the detection of ions associated with improvised explosives. The device was configured to test for nitrate (NO3-), nitrite (NO2-), chlorate (ClO3-), perchlorate (ClO4-), and urea nitrate (UN). Proof of concept was performed using extracts of soil containing inorganic oxidizers.
The development of these analytical methods allows the detection of smokeless powder components, fertilizers, and oxidizers and expands the suite of analytical methods available for the analysis of improvised explosives.
|
34 |
Manejo da palha, adubação nitrogenada potássica e uso de inoculante em soca de cana-de-açúcar / Management of harvest residue, nitrogen, potassium and use of inoculants in ratoon sugarcaneDiego Wyllyam do Vale 21 February 2013 (has links)
A colheita de cana-de-açúcar, sem despalha a fogo, vem crescendo no Brasil. Nesse sistema de cultivo, existem muitas dúvidas em relação ao manejo da palha, e das quantidades de nitrogênio e potássio a serem utilizadas. Objetivou-se avaliar o manejo da palha, adubação nitrogenada, potássica e uso do inoculante em área comercial de cana-de-açúcar. Para isso, instalou-se experimento na região de Piracicaba - SP, num Latossolo Vermelho Amarelo Distrófico, cultivado com a variedade de cana-de-açúcar CTC 9, em delineamento de blocos casualizados em esquema fatorial incompleto 3x6x4, totalizando 153 parcelas, sendo três manejos da palha-MP (distribuição da palha da cana em toda área-MPT, retirada da palha apenas nas linhas da cana-de-açúcar-MPRL e enleiramento da palha a cada duas linhas-MP2:1), seis doses de N (aplicação de 0, 60, 120 e 180 kg ha-1 de N, aplicação na linha da cana de solução contendo cinco espécies de bactérias fixadoras de nitrogênio na ausência de adubação nitrogenada e aplicação na linha da cana de solução contendo cinco espécies de bactérias fixadoras de nitrogênio mais 30 kg ha-1 de N mineral), quatro doses de K (0, 50, 100 e 150 kg de K2O ha-1) e três repetições. As variáveis analisadas ao longo das duas socas foram: análises químicas do solo, emissão de CO2, diagnose foliar, avaliações biológicas e tecnológicas e produção de colmos da cana-de-açúcar. A aplicação de nitrogênio e potássio afetou a fertilidade do solo, teor foliar de N, açúcar teórico recuperável e crescimento da cana-de-açúcar. A aplicação de 80 kg ha-1 de K2O é suficiente para apresentar alta produtividade da primeira (87 t ha-1) e da segunda soca de cana-deaçúcar (141 t ha-1) e não houve resposta a aplicação de nitrogênio mineral. A aplicação de inoculante não aumentou a produtividade da cana-de-açúcar. O MPRL se mostrou como o mais promissor em relação ao crescimento e produtividade da cana-de-açúcar. O MPRL apresentou maior emissão de carbono se comparado ao MP2:1 na 2a soca. Na 1ª soca, no MPT, MPRL e MP2:1, a emissão de CO2 foi de 1,7; 2,0 e 1,7 ?mol m-2 s-1, a temperatura foi de 21,7; 21,7; 21,2 ºC e a umidade foi de 11,1; 6,6 e 9,5%, respectivamente. Na 2ª soca, no MPT, MPRL e MP2:1, o CO2 foi de 1,8; 2,1 e 1,6 ?mol m-2 s-1, a temperatura foi de 21,4; 22,9; 22,4 ºC e a umidade foi de 16,9; 12,3 e 11,5%, respectivamente. A emissão de CO2 aumentou com o crescimento das plantas de cana-de-açúcar e oscilou de 6 a 12,4 ?mol m-2. / The harvesting of sugarcane, straw removal without fire, is growing in Brazil. In this culture system, there are many questions about the management of residue, and the amounts of nitrogen and potassium to be used. This study aimed to evaluate the straw management sugarcane, nitrogen, potassium and use of inoculants in commercial sugarcane. For this experiment was installed in Piracicaba - SP, in the Oxissol cultivated with the variety of sugarcane CTC 9, in a randomized block design in a incomplete factorial 3x6x4, totaling 153 plots, three management of stubble-MP (distribution of sugarcane trash in every area-MPT, removal of straw only rows of sugarcane MPRL and windrowing straw every two lines-MP2:1) six doses of N (application of 0, 60, 120 and 180 kg ha-1 of N, applied in line with the cane solution containing five species of nitrogen-fixing bacteria in the absence of nitrogen fertilizer application on line and cane solution containing five species of nitrogen-fixing bacteria plus 30 kg ha-1 of mineral N), four doses of K (0, 50 , 100 and 150 kg ha-1 of K2O) and three replications. The variables analyzed along the two years were: soil chemical analysis, CO2 emission, foliar diagnosis, biological and technological evaluations and straw yield of sugarcane. The application of nitrogen and potassium affect soil fertility, leaf N content, theoretical recoverable sugar and growth of sugarcane. The application of 80 kg ha-1 of K2O is sufficient to present the first high productivity (87 t ha-1) and second ratoon sugarcane (141 t ha-1) and there was no response from the application nitrogen mineral. The inoculant application did not increase productivity of sugarcane. The MPRL proved as the most promising in relation to growth and productivity of sugarcane. The MPRL had lower moisture and higher carbon footprint compared to MPT and MP2:1. In the 1st ratoon, the MPT, MPRL and MP2:1, the emission of CO2 was 1.7, 2.0 and 1.7 ?mol m-2 s-1, the temperature was 21.7, 21.7; 21.2 ºC and humidity was 11.1, 6.6 and 9.5%, respectively. In the 2nd ratoon in MPT, MPRL and MP2:1 first, the CO2 was 1.8, 2.1 and 1.6 ?mol m-2 s-1, the temperature was 21.4, 22.9; 22, 4 ºC and the humidity was 16.9, 12.3 and 11.5%, respectively. The emission of CO2 increased with the growth of plants sugarcane and oscillated 6 to 12.4 ?mol m-2 s-1.
|
35 |
Caractérisation à l'échelle locale des propriétés mécaniques de l'interphase pâte de ciment-granulat : application à la lixiviation / Characterization at the local scale of mechanical properties of the cement paste-aggregate interface : leaching ApplicationJebli, Mouad 30 November 2016 (has links)
Ce travail de thèse est consacré à la caractérisation des propriétés mécaniques de l’interphase pâte de ciment-granulat au cours de l’hydratation et au cours de la dégradation chimique par lixiviation. La microstructure de l'interphase entre la pâte de ciment et les granulats est caractérisée par une porosité supérieure à celle de la pâte de ciment. Cette zone constitue un point de fragilité dans le béton et ses propriétés affectent fortement le comportement mécanique du béton à l’échelle macroscopique et à l’échelle de la structure. Dans ce travail, la résistance de l’interphase pâte de ciment-granulat est analysée expérimentalement à l'échelle locale. Des essais expérimentaux sont réalisés sur des composites constitués de granulats liés par une pâte de ciment portland préparée avec un rapport Eau/Ciment de 0,5. Des dispositifs expérimentaux dédiés ont été conçus et réalisés de manière à être adaptés à la taille et à la forme des échantillons. La forme des échantillons utilisés et les outils expérimentaux développés permettent de solliciter directement l’interphase. A différents stades de l'hydratation, des échantillons de pâte de ciment seule et des composites sont soumis à des essais de compression, de traction et de cisaillement direct. L’étude des propriétés mécaniques de l’interphase pâte de ciment-granulat révèle une faiblesse de cette zone en termes de propriétés mécaniques..Le protocole expérimental mis au point a permis d’étudier les effets du mécanisme de lixiviation du calcium au niveau de l’interphase sur les propriétés mécaniques du béton à l’échelle locale. Compte tenu du temps caractéristique long du phénomène de lixiviation, la mise en situation expérimentale au laboratoire est accélérée en remplaçant l’eau par une solution de nitrate d'ammonium. Afin de quantifier le développement et la cinétique de dégradation au niveau de la liaison cimentée, les fronts de lixiviation du béton sont caractérisés à différents degrés de dégradation en utilisant la phénolphtaléine comme traceur. Des essais mécaniques locaux (compression, traction et cisaillement) sont réalisés sur les composites et sur la pâte de ciment à différents temps de dégradation. L’étude de l’effet de la lixiviation à l’échelle locale montre le rôle important de l’interphase pâte de ciment-granulat lors du processus de dégradation chimique sur les propriétés mécaniques du composite. / In this work, we presents an experimental study to characterize the mechanical properties at the local scale of the cement paste-aggregate interface during hydration and during chemical degradation by leaching.It is generally accepted that the microstructure of the interface between the aggregates and the cement paste is characterized by a higher porosity than that of cement paste. This makes this zone a weak point in the concrete. The particular properties of this zone strongly influence the mechanical behavior of concrete. In this work, the mechanical properties of the cement paste-aggregate composite, are experimentally studied. The experimental tests are performed on composites at classical aggregate scale (one centimeter of section). These composite are composed by and Portland cement paste and aggregate. The cement paste is prepared with a water/cement ratio of 0.5. The shape of the prepared composites makes them convenient for direct tensile and shear tests. At different stages of hydration, we performed direct tensile and shear tests on the composites by means of specific devices. The same tests were carried out on the cement paste in order to compare with composites results. The shape of the prepared composites makes them convenient to characterize the cement paste-aggregate interface. At different stages of hydration, the composites are subjected to compression tests, direct tensile tests or shear tests. The study of the mechanical properties of the cement-aggregates interface revealed that the cement paste-aggregate interface is the weakest zone in the composite.An experimental protocol was developed to study the effects of calcium leaching mechanism at the cement paste-aggregate interface on the mechanical properties of the concrete. As the process of leaching with the deionised water occurs very slowly, the experimental study in the laboratory is accelerated by replacing the water by ammonium nitrate solution. To quantify the development and kinetics of degradation at the cemented bond, the concrete leaching fronts are characterized at different levels of degradation by using phenolphthalein. Local mechanical tests (compression, tensile and shear) are performed on composite and cement paste at different stages of degradation. The experimental results show that there is a leaching effect on the alteration of the mechanical properties at the cement paste-aggregate interface.
|
36 |
Efficiency of nitrogen sources and rates on growth and dry matter yield of tifton 85 / Eficiência de fontes e doses de nitrogênio no crescimento e produção de matéria seca do capim-tifton 85Borges, Bernardo Melo Montes Nogueira [UNESP] 31 March 2016 (has links)
Submitted by Bernardo Melo Montes Nogueira Borges null (bernardonog@hotmail.com) on 2016-04-27T20:07:00Z
No. of bitstreams: 1
Tese_Bernardo_Melo_Montes_Nogueira_Borges.pdf: 1559546 bytes, checksum: 6d1bf6517586eaeee1a07a41f98d1490 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-04-29T22:10:32Z (GMT) No. of bitstreams: 1
borges_bmmn_dr_jabo.pdf: 1559546 bytes, checksum: 6d1bf6517586eaeee1a07a41f98d1490 (MD5) / Made available in DSpace on 2016-04-29T22:10:32Z (GMT). No. of bitstreams: 1
borges_bmmn_dr_jabo.pdf: 1559546 bytes, checksum: 6d1bf6517586eaeee1a07a41f98d1490 (MD5)
Previous issue date: 2016-03-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Forrageiras do gênero Cynodon são conhecidas por sua capacidade de resposta a altas doses de nitrogênio (N). Em condições tropicais o N pode se tornar um problema ambiental e financeiro devido à sua baixa eficiência de uso pelas plantas, principalmente como resultado de perdas por volatilização e/ou lixiviação. Portanto, objetivou-se com este trabalho avaliar fontes e doses de N no crescimento e produção de matéria seca do Tifton 85, bem como mudanças nas frações do carbono (C) no solo. Um experimento foi conduzido de 2012 a 2014, e constituiu de um fatorial em um delineamento de blocos ao acaso, onde os tratamentos foram a associação de duas fontes de N (nitrato de amônio [NA] e ureia), e cinco doses do nutriente (0, 60, 120, 180 e 240 kg ha-1 N por corte) aplicadas a cada 30 dias. Neste experimento foram utilizados NA e ureia enriquecidos com 15N como uma ferramenta para quantificar a recuperação do N advindo do fertilizante, nas plantas e no sistema solo-planta. As plantas foram cortadas para avaliar a produção de matéria seca, concentração de N na parte aérea e recuperação. O índice de área foliar (LAI), radiação fotossinteticamente ativa interceptada (PARi) e índice de clorofila (CI) foram mensurados no dia anterior ao corte. As amostras de solo foram coletadas nas parcelas que receberam NA e foram fracionadas em carbono orgânico particulado (POC), fração leve livre (FLF) e fração mineral (C-min); O teor de C nas frações foi quantificado. Os resultados demonstraram que o NA pode ser uma fonte mais eficiente somente quando a quantidade de precipitação é insuficiente para incorporar o fertilizante ao solo, resultando em maior produção de forragem, na somatória dos dois anos ambas as fontes produziram a mesma quantidade de matéria seca onde a maior produtividade 37,2 Mg ha-1, foi atingida com a dose de 210 kg ha-1 N por corte. Por outro lado, a quantidade de N recuperado pelo sistema de planta+solo foi maior quando a ureia foi utilizada, com destaque para a quantidade de N no solo, onde a ureia foi capaz de manter 10% mais N que o NA, a recuperação do nutriente diminuiu à medida que as doses foram elevadas. Nenhuma alteração no conteúdo de C foi notada devido às diferentes doses de N utilizadas, no entanto o POC e o C-min foram mais sensíveis às mudanças na camada de 0-0,1 m do que na camada de 0,1-0,2 m. / Cynodon hybrids are known by their ability to respond to high rates of nitrogen (N). In tropical conditions, N may become an environmental and financial issue due to its low efficiency of use by plants, mainly as a result of losses by volatilization and/or leaching. Therefore, the aims with this work were to evaluate N sources and rates on growth and dry matter yield of Tifton 85 and to determine changes in soil carbon (C) fractions in response to N fertilization. The 2-yr field experiment was conducted from 2012 to 2014, and consisted of a factorial design. Treatments were a combination of two sources of N (ammonium nitrate [AN] and urea) and five rates of the nutrient (0, 60, 120, 180 and 240 kg ha-1 N per cut) applied broadcast every 30 days. This study used AN and urea enriched with 15N as a tool to quantify the recovery of N derived from fertilizer in plants and the soil-plant system. Forage was cut at 30-d intervals for dry matter yield, shoot N concentration determinations and N recovery. The leaf area index (LAI), photosynthetic active radiation intercepted (PARi) and chlorophyll index (CI) were evaluated on the day before clipping. Soil samples were collected in plots receiving AN and they were fractionated in to particulate organic carbon (POC), free light fraction (FLF) and mineral fraction (C-min); The C concentration of the various fractions was determined. Results showed that AN was a more efficient source only when the amount of precipitation is insufficient to incorporate the fertilizer to the soil, resulting in increased production, in the sum of the two years both sources produced the same amount of dry matter in which the highest productivity, 37.2 t ha-1 , was achieved at the rate of 210 kg ha-1 N per cutting. On the other hand, the amount of N recovered by the plant+soil system was higher when urea was used, especially the amount of N in the soil, where urea was able to maintain 10% more N than AN, the nutrient recovery decreased as the rates were increased. No change in soil C concentration was detected in response to the different N rates used, however the POC and the C-min were more sensitive to changes in the layer of 0-0.1 m than the layer from 0.1-0.2 m.
|
37 |
Nitrogênio e potássio em cobertura na nutrição e produtividade do alho vernalizado livre de vírus e qualidade do alho minimamente processado / Yield and mineral nutrition of garlic in response to source of nitrogen and sources of potash and quality changes in fresh-peeled garlicTanamati, Fábio Yomei [UNESP] 02 June 2016 (has links)
Submitted by FÁBIO YOMEI TANAMATI null (fabioyomei@hotmail.com) on 2016-12-21T18:02:23Z
No. of bitstreams: 1
Tese- Fábio Final.pdf: 1752648 bytes, checksum: f9b77e3ee591fdbadfb4e16551e1bfc3 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-12-22T13:34:23Z (GMT) No. of bitstreams: 1
tanamati_fy_dr_bot.pdf: 1752648 bytes, checksum: f9b77e3ee591fdbadfb4e16551e1bfc3 (MD5) / Made available in DSpace on 2016-12-22T13:34:23Z (GMT). No. of bitstreams: 1
tanamati_fy_dr_bot.pdf: 1752648 bytes, checksum: f9b77e3ee591fdbadfb4e16551e1bfc3 (MD5)
Previous issue date: 2016-06-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O alho é uma hortaliça utilizada como condimento e como planta medicinal. O Brasil é um importante produtor/consumidor desta hortaliça, entretanto a produção nacional é insuficiente e portanto importa de quase 60% do alho consumido. Práticas precisas de manejo na produção e pós-colheita precisas podem resultar em economia na produção, aumento da produtividade e qualidade. Entre as práticas de manejo destaca-se a fertilização destaca-se pela influência direta na produção do alho e constituir um dos principais itens do custo de produção. Após a colheita a deterioração do alho minimamente processado (produto com maior valor agregado) pode ser diminuída através do armazenamento em temperatura controlada e atmosfera modificada. Com o objetivo de avaliar e documentar as melhores fontes e doses de nitrogênio e fontes potássio, bem como o melhor método para o armazenamento do alho minimamente processado foram conduzidos três ensaios que serão apresentados em três capítulos, sendo o primeiro intitulado “Fontes de nitrogênio e potássio sob a produtividade e nutrição mineral do alho”, o segundo capítulo intitulado “Produtividade e nutrição mineral do alho sob diferentes doses de nitrogênio e fontes de potássio”, e o terceiro capítulo intitulado “Efeito de diferentes temperaturas e atmosfera modificada sob as características qualitativas do alho minimamente processado”. Concluiu- se a) Diferentes fontes de N e K podem ser combinadas para a obtenção de máxima produção de alho comercial, b) o teor de nutrientes do alho não é influenciado pelas fontes de N e K ao ponto de constituir um fator crítico à produtividade do alho, c) Recomenda-se a dose 80 kg ha -1 de N como forma de obtenção de máxima eficiência do fertilizante e produtiva do alho vernalizado livre de vírus cv. Caçador, d) Não houve diferenças significativas na produção do alho acima da dose 80 kg ha -1 de N, a partir desta dose, o acúmulo de nutrientes no bulbo, de forma geral, foi inferior nos tratamentos K2SO4, e) baixa temperatura e atmosfera modificada contribuem significativamente para a manutenção da qualidade do alho minimamente processado, f) embalagem a vácuo mantém uma atmosfera consistentes em uma maior gama de temperaturas, g) as atmosferas modificadas com alto teor de CO2 podem influenciar a diminuição do valor de L* durante o armazenamento, h) a pungência do alho é mais bem conservada em embalagens a vácuo. / Garlic is used as a spice and as a medicinal plant, Brazil is an important producer/ consumer of this herb, however small domestic production stimulates import of about 60% the garlic consumed in this country. Management practices in the production and accurate post-harvest can result in savings in production and increasing in yield and quality. Among the management practices, fertilization is distinguished by its direct influence on the production of garlic and constitute one of the main cost items of production and postharvest deterioration of minimally processed garlic (product with higher added value) can be reduced by storing in controlled and modified atmosphere temperature. In order to assess and document the best sources and doses of nitrogen and potassium sources, as well as the more suitable storage method for fresh-peeled garlic we carried out three tests that will be presented in three chapters, the first entitled "Yield and mineral nutrition of vernalized virus free garlic in response to nitrogen and potassium sources topdressing" the second chapter entitled "Yield and mineral nutrition of garlic in response to nitrogen doses and potassium sources topdressing”, "Quality changes in fresh-peeled garlic cloves in relation to storage temperatures and modified atmospheres". From these assays we concluded that a) Different sources of N and K may be combined to obtain maximum production of commercial garlic, b) the garlic mineral content is not influenced by the sources of N and K to be considered a critical factor to garlic productivity, c) 80 kg ha -1 of N is the best way to obtain both maximum fertilizer efficiency and productive of virus free vernalizated garlic cultivar Caçador, d) from the dose 80 kg ha -1 , the lowest accumulation of nutrients in the bulb in SKO treatments suggests that potassium sulfate, alleviates possible effects of toxicity caused by excess NH4 + and reduces minerals export for bulb and thereby the ground, e) both low temperature and modified atmosphere significantly contribute to the maintenance of the quality of fresh-peeled garlic, f) vacuum packaging maintains an atmosphere consistent across a wider range of temperatures, g) modified atmospheres with high CO2 content can influence the decrease in L* value during storage, h) garlic pungency is better preserved in vacuum packaging.
|
38 |
Manejo da palha, adubação nitrogenada potássica e uso de inoculante em soca de cana-de-açúcar / Management of harvest residue, nitrogen, potassium and use of inoculants in ratoon sugarcaneVale, Diego Wyllyam do 21 February 2013 (has links)
A colheita de cana-de-açúcar, sem despalha a fogo, vem crescendo no Brasil. Nesse sistema de cultivo, existem muitas dúvidas em relação ao manejo da palha, e das quantidades de nitrogênio e potássio a serem utilizadas. Objetivou-se avaliar o manejo da palha, adubação nitrogenada, potássica e uso do inoculante em área comercial de cana-de-açúcar. Para isso, instalou-se experimento na região de Piracicaba - SP, num Latossolo Vermelho Amarelo Distrófico, cultivado com a variedade de cana-de-açúcar CTC 9, em delineamento de blocos casualizados em esquema fatorial incompleto 3x6x4, totalizando 153 parcelas, sendo três manejos da palha-MP (distribuição da palha da cana em toda área-MPT, retirada da palha apenas nas linhas da cana-de-açúcar-MPRL e enleiramento da palha a cada duas linhas-MP2:1), seis doses de N (aplicação de 0, 60, 120 e 180 kg ha-1 de N, aplicação na linha da cana de solução contendo cinco espécies de bactérias fixadoras de nitrogênio na ausência de adubação nitrogenada e aplicação na linha da cana de solução contendo cinco espécies de bactérias fixadoras de nitrogênio mais 30 kg ha-1 de N mineral), quatro doses de K (0, 50, 100 e 150 kg de K2O ha-1) e três repetições. As variáveis analisadas ao longo das duas socas foram: análises químicas do solo, emissão de CO2, diagnose foliar, avaliações biológicas e tecnológicas e produção de colmos da cana-de-açúcar. A aplicação de nitrogênio e potássio afetou a fertilidade do solo, teor foliar de N, açúcar teórico recuperável e crescimento da cana-de-açúcar. A aplicação de 80 kg ha-1 de K2O é suficiente para apresentar alta produtividade da primeira (87 t ha-1) e da segunda soca de cana-deaçúcar (141 t ha-1) e não houve resposta a aplicação de nitrogênio mineral. A aplicação de inoculante não aumentou a produtividade da cana-de-açúcar. O MPRL se mostrou como o mais promissor em relação ao crescimento e produtividade da cana-de-açúcar. O MPRL apresentou maior emissão de carbono se comparado ao MP2:1 na 2a soca. Na 1ª soca, no MPT, MPRL e MP2:1, a emissão de CO2 foi de 1,7; 2,0 e 1,7 ?mol m-2 s-1, a temperatura foi de 21,7; 21,7; 21,2 ºC e a umidade foi de 11,1; 6,6 e 9,5%, respectivamente. Na 2ª soca, no MPT, MPRL e MP2:1, o CO2 foi de 1,8; 2,1 e 1,6 ?mol m-2 s-1, a temperatura foi de 21,4; 22,9; 22,4 ºC e a umidade foi de 16,9; 12,3 e 11,5%, respectivamente. A emissão de CO2 aumentou com o crescimento das plantas de cana-de-açúcar e oscilou de 6 a 12,4 ?mol m-2. / The harvesting of sugarcane, straw removal without fire, is growing in Brazil. In this culture system, there are many questions about the management of residue, and the amounts of nitrogen and potassium to be used. This study aimed to evaluate the straw management sugarcane, nitrogen, potassium and use of inoculants in commercial sugarcane. For this experiment was installed in Piracicaba - SP, in the Oxissol cultivated with the variety of sugarcane CTC 9, in a randomized block design in a incomplete factorial 3x6x4, totaling 153 plots, three management of stubble-MP (distribution of sugarcane trash in every area-MPT, removal of straw only rows of sugarcane MPRL and windrowing straw every two lines-MP2:1) six doses of N (application of 0, 60, 120 and 180 kg ha-1 of N, applied in line with the cane solution containing five species of nitrogen-fixing bacteria in the absence of nitrogen fertilizer application on line and cane solution containing five species of nitrogen-fixing bacteria plus 30 kg ha-1 of mineral N), four doses of K (0, 50 , 100 and 150 kg ha-1 of K2O) and three replications. The variables analyzed along the two years were: soil chemical analysis, CO2 emission, foliar diagnosis, biological and technological evaluations and straw yield of sugarcane. The application of nitrogen and potassium affect soil fertility, leaf N content, theoretical recoverable sugar and growth of sugarcane. The application of 80 kg ha-1 of K2O is sufficient to present the first high productivity (87 t ha-1) and second ratoon sugarcane (141 t ha-1) and there was no response from the application nitrogen mineral. The inoculant application did not increase productivity of sugarcane. The MPRL proved as the most promising in relation to growth and productivity of sugarcane. The MPRL had lower moisture and higher carbon footprint compared to MPT and MP2:1. In the 1st ratoon, the MPT, MPRL and MP2:1, the emission of CO2 was 1.7, 2.0 and 1.7 ?mol m-2 s-1, the temperature was 21.7, 21.7; 21.2 ºC and humidity was 11.1, 6.6 and 9.5%, respectively. In the 2nd ratoon in MPT, MPRL and MP2:1 first, the CO2 was 1.8, 2.1 and 1.6 ?mol m-2 s-1, the temperature was 21.4, 22.9; 22, 4 ºC and the humidity was 16.9, 12.3 and 11.5%, respectively. The emission of CO2 increased with the growth of plants sugarcane and oscillated 6 to 12.4 ?mol m-2 s-1.
|
39 |
Termohromno ponašanje halogenidnih kompleksa kobalta(II) u višekomponentnim sistemima / Thermochromic behaviour of cobalt(II) halide complexes in multicomponent systemsDožić Sanja 11 April 2014 (has links)
<p>U ovoj doktorskoj disertaciji proučavano je građenje i termohromno ponašanje hloro kompleksa kobalt(II) jona u tri različita medijuma: amonijum-nitrat + <em>z</em>formamid (z= 2, 3, 4, 5, 6 i 20), amonijum-nitrat + <em>z</em>N-metilformamid (<em>z </em>= 3, 4, 5, 6 i 20) i amonijum-nitrat + <em>zN,N</em>-dimetilformamid (<em>z</em> = 3) u temperaturnom intervalu od 308,15 do 348,15 K. Cilj ovog istraživanja je bio određivanje stabilnosti termohromnih kompleksa kobalta(II) koji se grade sahloridnim i nitratnim jonima i molekulima rastvarača, pronalaženje kvalitativne i kvantitativne zavisnosti konstanti stabilnosti kompleksa kobalta(II) od temperature i molskog odnosa komponenti ispitivanih sistema. Termodinamički parametri, koji karakterišu reakcije asocijacije u ispitivanim sistemima izračunati su na osnovu dobijenih konstanti stabilnosti na različitim temperaturama. Drugi deo ovog rada obuhvata fizičko-hemijsku karakterizaciju ispitivanih sistema, i to: merenje gustine, provodljivosti i njihove viskoznosti. Na osnovu dobijenih podataka razmotrene su vrste interakcija koje se javljaju među česticama rastvarača i rastvorene supstance, kao i njihov uticaj na građenje kompleksnih čestica kobalta(II). Ispitivani sistemi su posebno interesantni, jer predstavljaju dobre medijume za ispitivanje termohromizma u praksi.</p> / <p>In this thesis absorption spectra of cobalt(II) chloride in three ammonium nitrate binary mixtures with organic solvents (formamide, N-methylformamide and <em>N,N</em>-dimethylformamide) at different temperatures (from 308.15 to 248.15 K) and compositions have been investigated in the wavelength range 400-800 nm. Influence of the temperature and composition of the mixture on complex formation between cobalt(II) and nitrate ions, chloride ions and/or solvent molecules have been studied. Thermodynamic parameters for cobalt(II)-ligand association in different solventswere also determined. The second part of this work involves physical-chemical characterization of the studied systems, namely: density, electrical conductivity and viscosity measurements. On the basis of the obtained data, the types and nature of the solute-solvent interactions that occur, as well as their impact on the cobalt(II) complex formation were discussed. In all investigated systems, complexes of cobalt(II) change the geometry and colour from pale pink to dark blueupon addition of chloride ions and upon heating/cooling. Hence, additional chemical energy can be stored in such system. Because the effective working temperatures match very well with that readily achievable under sunlight, these thermochromic systems present an example of novel materials suitable for auto-regulated protection and energy storage.</p>
|
40 |
Građenje halogenidnih kompleksa kobalta(II) u rastopima smeše neorganskih soli i polarnih organskih jedinjenja / Formation of cobalt(II) halide complexes in molten mixtures of inorganic salts with polar organic compoundsMatijević Borko 21 September 2011 (has links)
<p>U ovoj doktorskoj disertaciji proučavano je građenje kompleksa kobalta(II) sa hloridnim i bromidnim jonima u rastopima koji sadrže jednu neorgansku so i jedno organsko jedinjenje i/ili vodu pri različitom sastavu sistema i na različitim temperaturama. Jedan od sistema je amonijum-nitrat – acetamid – voda sastava NH<sub>4</sub>NO<sub>3</sub>∙(2,61-z)CH<sub>3</sub>CONH<sub>2</sub>∙zH<sub>2</sub>O (z = 0,0 1,61 i 2,61), a drugi sistem je amonijum–nitrat – dimetilsulfoksid (DMSO) sastava NH<sub>4</sub>NO<sub>3</sub>∙zDMSO (z = 1 – 6), na različitim temperaturama (35, 45, 55 i 65 <sup>o</sup>C). Cilj ovog istraživanja je bio određivanje stabilnosti kompleksa kobalta koji se grade sa sa halogenidnim jonima i komponentama rastvarača, pronalaženje kvalitativne i kvantitativne zavisnosti konstanti stabilnosti kompleksa kobalta(II) sa halogenidnim jonima od temperature i molskog odnosa komponenti sistema NH<sub>4</sub>NO<sub>3</sub>∙(2,61-z)CH<sub>3</sub>CONH<sub>2</sub>∙zH<sub>2</sub>O odnosno NH<sub>4</sub>NO<sub>3</sub>∙zDMSO, određivanje termodinamičkih parametara koji karakterišu reakcije asocijacije u ovim sistemima.</p> / <p>In this dissertation the complex formation between cobalt(II) and halide ions in the melts consisting of one inorganic salt, an organic compound and/or water has been studied at different temperatures. Two molten salt systems have been investigated: 1) ammonium nitrate-acetamide-water system NH<sub>4</sub>NO<sub>3</sub>∙(2,61-z)CH<sub>3</sub>CONH<sub>2</sub>∙zH<sub>2</sub>O (z = 0.0 1.61 2.61) and 2) ammonium nitratedimethyl sulfoxide NH<sub>4</sub>NO<sub>3</sub>∙zDMSO (z = 1 – 6), at four different temperatures: 35, 45, 55 and 65 <sup>o</sup>C. The purpose of this work was to determine stability of cobalt(II) complexes formed with the halide ions and the components of the solvents, to discribe the qualitative and quantitative relationships between the stability of the complexes and the melt composition, as well as the changes in the cobalt(II) coordination due to a complex formation. Thermodynamic parameters for cobalt(II) – halide association process in these melts were alsodetermined.</p>
|
Page generated in 0.0769 seconds