Le coût de la maintenance aéronautique pourrait être réduit en proposant des stratégies d’inspection « intelligentes » intégrant des outils prédictifs de l’évolution des défauts, comme la vitesse de propagation de la corrosion intergranulaire.Dans cette thèse, nous avons cherché à quantifier les deux modes d’endommagement associés à la corrosion intergranulaire sur un alliage 2024 : la composante « perforante » (dissolution des pointes de joint de grain) et la composante « émoussante » (dissolution des parois des grains dans les cavités intergranulaires). Pour évaluer la composante « perforante », nous proposons une nouvelle variante de la méthode TFP (méthode OTFP) plus complète car elle ne se limite pas à caractériser le défaut le plus rapide mais permet de suivre l’ensemble des défauts perforants grâce à la nature optique de la détection. Dans cette méthode, le dispositif expérimental laisse libre la face de détection, ce qui permet de prélever l’électrolyte issu des cavités intergranulaires et de procéder à son analyse chimique. Cette donnée, peu connue à ce jour, a été utilisée pour valider des modèles de « transport réactif » qui pourront servir de base à des simulations prédictives intégrant l’effet de la nature de l’environnement. La porosité au sein du matériau induite par la corrosion intergranulaire et amplifiée par la dissolution « émoussante » a été suivie en temps réel par mesure de la conductivité électrique avec une sonde à courants de Foucault. D’abord calibrées en régime potentiostatique, ces méthodes se sont par la suite révélées efficaces pour évaluer l’endommagement associé à la corrosion intergranulaire lors d’une corrosion de type atmosphérique. / Costs of aeronautical maintenance can be reduced by implementation of “smart” inspection strategies integrating predictive data on the evolution of defects such as the propagation rate of intergranular corrosion.In this work, intergranular corrosion damage on 2024 aluminium alloy was characterized by two modes : the “perforating” damage (dissolution of the grain boundary tips) and the “blunting” damage (dissolution of the grain walls in the intergranular cavities). To evaluate the “perforating” damage, a new version of the TFP method (OTFP method) which is more complete, was designed. The OTFP method allows to detect all the intergranular corrosion defects and not only the fastest full penetrating grain boundary thanks to the optical nature of the detection. In this method the detection backside of the thin foil is free, which makes possible the collection of the trapped electrolyte in the intergranular cavities to carry out its chemical analysis. This not well-known data, was used to validate “mass-transport” models which could be implemented in predictive simulations considering the effect of the environmental conditions. The porosity inside the foil induced by the intergranular corrosion and enhanced by the “blunting” dissolution was followed in real-time by measuring the electrical conductivity using an eddy current probe.These methods were first calibrated in potentiostatic tests and then successfully applied to evaluate the intergranular corrosion damage in atmospheric corrosion conditions.

Les matériaux hybrides organique/inorganiques ont reçu beaucoup d'attention ces dernières années dans les études des nanomatériaux. En effet, ils possèdent des propriétés physiques et chimiques uniques grâce aux effets synergiques de chaque composant. En particulier, les nanoparticules de silice (SiO2) présentent des caractéristiques intéressantes, comme une bonne stabilité chimique et thermique. Elles peuvent être préparées de différentes tailles et peuvent aussi être facilement fonctionnalisées. Les polymères conducteurs intrinsèques comme le polythiophène et la polyaniline (PANI) peuvent exister sous différents états d'oxydation et donc répondre à des stimuli extérieurs en changeant une de leur caractéristique (couleur, conductivité, etc…). La PANI est un polymère non-toxique, thermiquement stable et peu coûteux avec une conductivité relativement élevée qui a été utilisée comme film antistatique, matériel d'électrode, inhibiteur de corrosion et comme surface sensible de capteur. Depuis la découverte des polymères conducteurs en 1977, plusieurs travaux ont été effectués sur la préparation, la caractérisation et les applications de films polymériques construits à la surface de matériaux comme la silice. Parmi les différents types de composites existants, les particules de type cœur@coquille composées d’un cœur inorganique et d’une couronne de polymère sont les plus prometteurs. Dans cette étude, nous avons donc décidé de travailler sur la synthèse de composites cœur@coquille constitués d’une coquille de PANI et d’un cœur de particules de silice.Dans la littérature, en utilisant des protocoles expérimentaux similaires, deux morphologies très contradictoires ont été obtenues après la polymérisation par oxydation chimique d'aniline en présence de particules de silice : cœur@coquille et framboise (structure inversée avec la PANI comme cœur). Nous avons alors décidé de réexaminer la synthèse de PANI en présence de particules de silice. Pour cela, nous avons, dans un premier temps, synthétisé des particules de silice monodisperses de différentes tailles (300, 160 et 90 nm) par procédé Stöber. Nous avons ensuite réalisé la polymérisation chimique de l'aniline en présence de ces particules de silice dans des conditions contrôlées afin de promouvoir une adsorption des ions aniliniums en surface des particules. Différents paramètres expérimentaux ont été étudiés tels que la température, la concentration en réactifs, la taille des particules… Les résultats en termes de morphologie sont discutés en fonction de ces paramètres. Dans un second temps, nous avons fonctionnalisé la surface des particules de silice par un alcoxysilane afin de favoriser la polymérisation de l’aniline à la surface des particules. Ainsi, nous avons obtenu des structures SiO2@PANI avec une épaisseur de polymère contrôlable. La dernière partie de ce travail traite des premiers essais qui ont été réalisés afin d’utiliser ces composites SiO2@PANi pour des applications environnementales. Deux applications ont notamment été envisagées, l'adsorption de métaux pour l'aspect de particule et la détection de gaz pour les capacités conductrices de la PANI. / Organic/inorganic hybrid materials have received much attention in recent years such as in the field of nano-materials. Indeed, these materials possess unique physical and chemical properties due to the synergistic effect of both components. In particular, silica nanoparticles (SiO2) present interesting properties, such as good chemical and thermal stabilities. They can be prepared in different size and can be easily chemically modified. Intrinsically conducting polymers such as polythiophene and polyaniline (PANI) can exist in different oxidation states and respond to external stimuli by changing one of their characteristics (color, conductivity, …). PANI is a non-toxic, thermally stable and low cost polymer with relatively high conductivity that has been used as antistatic coating, electrode materials, corrosion inhibitor and active layer of sensors. Since the discovery of conducting polymer in 1977, several works have been carried out on the preparation, characterization and applications of polymeric films build on various surfaces like silica. Among the different kinds of composites that exist, inorganic-polymer core-shell nanoparticles are more promising candidates. In this study, we decided to work on the synthesis of core@shell hybrid compounds based on PANI shells and silica nanoparticles cores.In the literature, using similar experimental protocols, two morphologies have been obtained after chemical polymerization of aniline in the presence of silica particles: core@shell and raspberry (inverted structure with PANI as core). We thus decided to reinvestigate the synthesis of PANI in the presence of silica particles. For this, we first synthesized silica particles with different sizes by Stöber process. We then performed the chemical polymerization of aniline in the presence of these naked silica particles under different conditions: temperature, concentration of reactive. However, in all cases, we never managed to obtain core@shell structures. Finally, we succeed in developing a method to prepare these core@shell particles which relies on the functionalization of the SiO2 by alkoxysilanes followed by the polymerization of aniline at room temperature. A series of core-shell particles with tunable PANI thickness has been prepared by this method. The last part of this work deals with the first tests that have been carried out in order to use these composites SiO2@PANi for environmental applications. Two applications have been considered, the adsorption of metals for the particle appearance and the detection of gas for the conductive capacities of the PANI.

Philosophiae Doctor - PhD / One of the most powerful aspects of conducting polymers is their ability to be nanostructured through innovative, synthetically manipulated, transformations, such as to tailor-make the polymers for specialized applications. In the exponentially increasing wide field of nanotechnology, some special attention is being paid to innovative hybrid dendrimer-core based polymeric smart materials. Star copolymers are a class of branched macromolecules having a central core with multiple linear polymer chains extending from the core. This intrinsic structural feature yields a unique 3D structure with extended conjugated linear polymer chains, resulting in star copolymers, which have higher ionic conductivities than their corresponding non-star conducting polymer counterparts. In this study an in-depth investigation was carried out into the preparation and characterization of specialized electronic smart materials. In particular, the preparation and characterization of novel conducting dendrimeric star copolymers which have a central poly(propylene imine) (PPI) dendrimer core with conducting polypyrrole (PPy) chains extending from the core was carried out. This involved, first, the preparation of a series of dendrimeric polypyrrole poly(propylene imine) star copolymers (PPI-co-PPy), using generations 1 to 4 (G1 to G4) PPI dendrimer precursors. The experimental approach involved the use of both chemical and electrochemical synthesis methods. The basic procedure involved a condensation reaction between the primary amine of a diamino functional PPI dendrimer surface and 2-pyrrole aldehyde, to afford the pyrrole functionalized PPI dendrimer (PPI-2Py). Polymerization of the intrinsically contained monomeric Py units situated within the dendrimer backbone was achieved via two distinctly different routes: the first involved chemical polymerization and the second was based on potentiodynamic oxidative electrochemical polymerization. The star copolymers were then characterized using various sophisticated analytical techniques, in-situ and ex-situ. Proton nuclear magnetic resonance spectroscopy (1HNMR) and Fourier transform infrared spectroscopy (FTIR) were used to determine the structures. Scanning electron microscopy (SEM) was used to determine the morphology. Themogravimetric analysis (TGA) was used to study the thermal stability of the prepared materials. X-ray diffraction analysis (XRD) was used to study the structural make-up of phases, crystallinity and amorphous content. Hall effect measurements were carried out to determine the electrical conductivity of the chemically prepared star copolymers. The PPI-co-PPy exhibited improved thermal stability compared to PPI-2Py, as confirmed by TGA. SEM results showed that the surface morphology of the functionalized dendrimer and star copolymer differed. The surface morphology of the chemically prepared star copolymers resembled that of a flaky, waxy material, compared to the ordered morphology of the electrochemically grown star copolymers, which resembled that of whelk-like helixes. In the case the electrochemically grown star copolymers, SEM images recorded at higher magnifications showed that the whelk-like helixes of the star copolymers were hollow tubes with openings at their tapered ends, and had an average base diameter of 2.0 mu;m. X-ray diffraction analysis of the first generation star copolymer G1PPI-co-PPy revealed a broadly amorphous structure associated with PPy, and crystalline peaks for PPI. Cyclic voltammetry (CV), square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS) techniques were used to study and model the electrochemical reactivity of the star copolymer materials. Electrochemical impedance spectroscopy data showed that the G1PPI-co-PPy exhibited slightly higher ionic conductivity than pristine PPy in lithium perchlorate. The second generation star copolymer G2PPI-co-PPy electrochemically deposited on a platinum (Pt) electrode had a lower electrochemical charge transfer resistance compared to electrodeposited polypyrrole (PPy) on a Pt electrode, and bare Pt. The decrease in charge transfer resistance was attributed to an increase in the conjugation length of the polymer as a result of the linking of the highly conjugated PPy to the PPI dendrimer. Bode impedimetric analysis indicated that G2PPI-co-PPI was a semiconductor, with a maximum phase angle shift of 45.3° at 100 MHz. The star copolymer exhibited a 2- electron electrochemistry and a surface coverage of 99%. Results of Hall effect measurements showed that the star copolymer is a semiconducting material, having a conductivity of 0.7 S cm-1, in comparison to the 1.5 S cm-1 of PPy. To the best of my knowledge, these new star copolymers have not been reported in the open literature. Their properties make them potentially applicable for use in biosensors. / South Africa

Made available in DSpace on 2016-08-31T13:24:13Z (GMT). No. of bitstreams: 1 SauloSCP_DISSERT.pdf: 1780685 bytes, checksum: 26e2c64d2806193b0477447f02412ad2 (MD5) Previous issue date: 2013-12-12 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Brazil has high potential for forage production, rightfully be located in a tropical climate region. In the Brazilian Northeast irrigation of pastures has been implemented as a way to compensate for the lack of rain for most of the year.The scarcity of good quality waterand increasing their demand to meet the population growth has led to the use of water sources of lower quality, among which the saline water, very common in semiarid regions. Forage crops are considered tolerant plants to salinity, being variables of growth and production very important factors to study the effects caused by salt stress. TheCynodon spp. cv. Tifton 85 andTanzania grass (Panicum maximum) are forages that have gained prominence in recent years, are often recommended to feed animals worldwide. Thus, in order to evaluate the performance of Tifton 85 and Tanzania grasses with the use of saline water and of two irrigation methods, grown in Alfissolof the semiarid region of Mossoró RN, developed this research in greenhouse at UFERSA, in experimental design completely randomized, with treatments in a factorial, with four replications. Treatments included a combination of two irrigation methods (drip and sprinkler)with five salinity levels of irrigation water (S1=0,5; S2=1,5; S3=2,5; S4=3,5 e S5=4,5 dS m-1). Evaluated the yield components height (ALT), fresh biomass (FMF) and dry biomass (FMS) of shoots of Tifton 85 and Tanzaniagrasses, plus tiller number (NP) and leaf area (AF) of Tanzania grass.Monitoring was conducted soil salinity, being determined over the cycle the electrical conductivity of the saturation extract (CEes), the RAS and the pH of soils under grasses. In a generalized form, irrigation water with high salinity inhibited the growth of plants Tifton 85, reduced the FMF and FMS of Tifton 85 and Tanzania grasses and reduced the NP and AF Tanzania grass, however, is possible to obtain good yields CEa with a maximum of 2.8 dS m-1. The increase in salinity resulted in a linear increase of CEes and soil RAS, as well, caused a reduction in the soil pH. The method of drip irrigation method was superior to sprinkler irrigation in the production of Tanzania grass when using higher salinity water / O Brasil possui elevado potencial para a produção de forragem, justamente por localizar-se numa região de clima tropical. No Nordeste brasileiro a irrigação de pastagens tem sido implantada como forma de compensar a falta de chuvas na maior parte do ano.A escassez de água de boa qualidade e o aumento da sua demanda para atender ao crescimento da população tem provocado a utilização de fontes de águas de qualidade inferior, dentre as quais as águas salinas, muito comuns nas regiões semiáridas. As plantas forrageiras são consideradas plantas tolerantes à salinidade, sendo as variáveis de crescimento e produção fatores muito importantes parase estudar os efeitos provocados pelo estresse salino. O Cynodon spp. cv. Tifton 85 e o capim Tanzânia (Panicum maximum)são forrageiras que vêm se destacando nos últimos anos, sendo frequentemente recomendadas para alimentação de animais em todo o mundo.Assim, com o objetivo de avaliar o desempenho das gramíneas Tifton 85 e Tanzânia com o uso de água salina e dedois métodos de irrigação, cultivadas em Argissolo Vermelho Amarelo da região do semiárido de Mossoró RN desenvolveu-seesta pesquisa em casa de vegetação da UFERSA, em delineamento experimental inteiramente aleatorizado, com tratamentos em esquema fatorial, com quatro repetições. Os tratamentos consistiram da combinação de dois métodosde irrigação (gotejamento e aspersão) com cincos níveis de salinidade da água de irrigação (S1=0,5; S2=1,5; S3=2,5; S4=3,5 e S5=4,5 dS m-1). Avaliaram-se os componentes de produção altura (ALT), fitomassa fresca (FMF) e fitomassa seca (FMS) da parte aérea dos capins Tifton 85 e Tanzânia, além do número de perfilhos (NP) e área foliar (AF) do capim Tanzânia. Foi realizado monitoramento da salinidade do solo, sendo determinados ao longo dos ciclos a condutividade elétrica do extrato de saturação (CEes), o pH e a RAS do solo cultivado com as gramíneas. De forma generalizada, a água de irrigação de elevada salinidade inibiu o crescimento de plantas de capim Tifton 85, reduziu a FMF e a FMS dos capins Tifton 85 e Tanzânia e reduziu o NP e a AF do capim Tanzânia,porém, é possível obter boas produções com uma CEa máxima de 2,8dS m-1. O incremento na salinidade da água resultou em aumento linear da CEese da RAS do solo, bem como, provocou a redução no pH do solo. O método de irrigação por gotejamento foi superior ao método de irrigação por aspersão na produção de capim Tanzânia quando se utiliza água de maior nível de salinidade

FREIRE, Márcio de Melo. Funções de Green em Mecânica Estatística. 2014. 56 f. Dissertação (Mestrado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2014. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2014-09-12T19:48:53Z No. of bitstreams: 1 2014_dis_mmfreire.pdf: 935092 bytes, checksum: 28a3a9a1ed16462d01e40ff411a01564 (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2014-09-12T19:50:01Z (GMT) No. of bitstreams: 1 2014_dis_mmfreire.pdf: 935092 bytes, checksum: 28a3a9a1ed16462d01e40ff411a01564 (MD5) / Made available in DSpace on 2014-09-12T19:50:01Z (GMT). No. of bitstreams: 1 2014_dis_mmfreire.pdf: 935092 bytes, checksum: 28a3a9a1ed16462d01e40ff411a01564 (MD5) Previous issue date: 2014 / Neste trabalho estabeleceremos as definições das funções de Green em mecânica estatística e suas propriedades básicas. Estas funções dependem duplamente do tempo e da temperatura. Isto pode ser observado por meio de suas definições, onde aparecem os valores médios dos produtos de operadores. Neste caso a média é feita sobre o ensemble grão-canônico. Os operadores envolvidos nestas funções satisfazem a equação de movimento de Heisenberg, o que nos permite descrever as equações de evolução para as funções de Green. Por meio da representação espectral das funções de correlação temporal, que é feita através da introdução de uma transformada de Fourier para mudar o sistema do espaço dos tempos para o espaço das frequências, podemos obter as representações espectrais para as funções de Green retardada, avançada e causal. Por último, faremos o uso da função de Green retardada para descrever a condutividade elétrica de um sistema de elétrons submetido a um campo elétrico externo dependente de tempo, em outras palavras, descreveremos o tensor de condutividade elétrica em termos da função de Green retardada e, por último, calcularemos a condutividade elétrica de um sistema de elétrons e fônons.

Two field experiments were conducted on sandy loam soils in OKhahlamba Local Municipality (OLM) (Bergville area), KwaZulu-Natal province in South Africa, during the rainy seasons of 2014/15 and 2015/16 to study the effect of calcium source (gypsum) fertilizer application on yield and quality of groundnut (Arachis hypogaea L.). The household economy of OLM is mostly dependent on agriculture and the majority of farmers in this area are small-scale farmers subsisting mainly on maize (constituting the staple diet) and groundnut production. Crop diversification, therefore, becomes an important aspect for farmers, and this is traditionally done using crops that are produced in almost similar agronomic circumstances to that of maize under dryland conditions. A large proportion of the OLM population depend on groundnut as a vital supplement to their daily food requirements, particularly as a cheap source of protein for resource-poor farmers. Therefore, any scientific approach to increase the yield of groundnut should be considered important in the livelihood of this community. Moreover, groundnut is an excellent rotational crop, since it responds well to fertilizer applied to previous crop and maize, as well as to crop, since it responds well to fertilizer applied to previous crop and maize, as well as to nitrogen left over by peanut. Thus, farmers save money because they use less fertilizer. The consideration for this study was based upon the above. The experiment was laid in a randomised complete block design with factorial arrangement, which was replicated three times in 48 plots. The factors studied were four levels of gypsum (CaSO4.2H2O) i.e. 0 kg/ha, 500 kg/ha, 750 kg/ha, and 1000 kg/ha and four levels of lime (MgCO3.CaCO3) i.e. 0 kg/ha, 250 kg/ha, 500 kg/ha, 750 kg/ha. Soil pH, cation exchange capacity (CEC), electrical conductivity (EC), pod yield, seed yield, 100 seeds weight, shelling percentage, dry shoot weight, seed moisture content percentage at harvest, and leaf calcium concentration data were collected prior to, and post harvesting. The application of 500 kg gypsum/ha alone acted as a liming factor for legumes, decreasing acid stress on nodulating bacteria, and improved soil chemical properties (increased soil pH), vegetative growth, yield, and quality of groundnut. The smallholder famers can afford this application rate, since gypsum acts both as a liming factor and as a calcium source to improve crop yield. The application of 1000 kg gypsum/ha improved seed yield, shelling percentage as well as kernel weight, which is yield, and quality of groundnut under dryland conditions. Since smallholder farmers practise dryland production, it is advisable to adopt the application of gypsum at the rate of 1000 kg/ha to improve yield and quality of groundnuts. It was also found to be more economical than using both gypsum and lime. The application of 500 kg gypsum per hectare in combination with 250 kg lime per hectare produced the highest shelling percentage. This combination of two calcium sources (gypsum and lime) is not recommended for small-scale farmers because it is not economical. The application of 500 kg gypsum per hectare in combination with 750 kg lime per hectare increased pod yield. However, this combination is also not recommended because it is not cost-effective. The application of 1000 kg gypsum per hectare in combination with 500 kg lime per hectare increased seed yield and produced sound mature kernel (SMK), whereas the application of 1000 kg gypsum alone per hectare also increased seed yield. This combination is also considered unacceptable due to the high increase in input costs. The application of 750 kg lime per hectare was more effective as an acid ameliorant and led to the improvement of the chemical composition of the soil (increased soil pH), resulting in a higher shoot weight of groundnut. This application also provided the catalyst for stimulating phosphorus production and enhancing the growth of an extensive root system for absorbing water and nutrients. The use of lime in acid soils is highly beneficial because it improves the chemical composition of the soil, ensures the availability of nutrients to plants, serves as an efficient calcium source, and ultimately leads to an improvement in yield. Results show that the application of gypsum at 1000 kg/ha and lime at 500 kg/ha respectively, significantly improved peanut yield and soil pH. The combination of gypsum and lime (500 kg/ha gypsum and 250 kg/ha lime) significantly improved shelling percentage (yield). Based on data on yield, yield components, and soil chemical properties, it is concluded that gypsum is the best calcium source fertilizer for groundnut production in OLM and lime should only be applied on acid soils to attain optimum groundnut yield in the region / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Research with the sunflower crop currently emphasize the use for oil extraction for biodiesel production. The sunflower, because it is a culture of broad adaptation and soil nutrient cycling, has been deployed in systems of crop rotation. An important strategy for the success of any crop seed is the use of good quality in order to obtain suitable plant stand. But often lacking appropriate tests to determine the quality of seeds, making the choice of the best lots. In this sense, the objective is to determine the appropriate methodology for analysis of the effect of sunflower seeds, through electrical conductivity mass and individual test and pH exudates, as well as determining the number of samples in the number of seeds for evaluation of Individual electrical conductivity of sunflower seeds. Experiments were conducted, which evaluated the mass electrical conductivity, electrical conductivity and pH of the individual exudate and established the relationship of these tests with the test field emergence. The electrical conductivity mass and individual are promising in the separation of lots of sunflower seeds, and the best conditions for performing the electrical conductivity test mass is 25 seeds, 25 ml of water and reading done after an hour of soaking. For the electrical conductivity test individual periods 1 - 24 hours have high correlation between field emergence and electrical conductivity individual. The sample size seed number, to evaluate the conductivity of sunflower seed, is dependent on the time of seed imbibition. Soaking times an hour using the smallest possible sample sizes. Considering the range of 15 μS cm-1 seed-1 is recommended sample size of 100 seeds. / As pesquisas com a cultura do girassol, atualmente, enfatizam a utilização para fins de extração de óleo para produção de biodiesel. O girassol, por ser uma cultura de ampla adaptação e ciclagem de nutrientes do solo, vem sendo implantado nos sistemas de rotação de culturas. Uma estratégia importante para o sucesso de qualquer cultivo é a utilização de sementes de boa qualidade, de forma a obter adequado estande de plantas. Porém, muitas vezes faltam testes apropriados para determinação da qualidade das sementes, dificultando a escolha dos melhores lotes. Neste sentido, objetiva-se a determinação da metodologia adequada para análise do vigor de sementes de girassol, através de testes de condutividade elétrica massal e individual e teste do pH do exsudato, bem como, determinar o número de amostra em número de sementes para avaliação da condutividade elétrica individual de sementes de girassol. Foram realizados experimentos, em que se avaliou os testes da condutividade elétrica massal, da condutividade elétrica individual e do pH do exsudato e se estabeleceu a relação destes testes com o teste de emergência em campo. Os testes de condutividade elétrica massal e individual são promissores na separação dos lotes de sementes de girassol, sendo que, a condição mais adequada para realização do teste de condutividade elétrica massal é de 25 sementes, 25 ml de água e leitura realizada após uma hora de embebição. Para o teste de condutividade elétrica individual, períodos de 1 a 24 horas apresentam alta correlação entre emergência em campo e condutividade elétrica individual. O tamanho de amostra em número de sementes, para avaliar a condutividade elétrica das sementes de girassol, é dependente do tempo de embebição das sementes. Tempos de embebição de uma hora possibilitam utilizar os menores tamanhos de amostras. Considerando a amplitude de 15 μS cm-1 semente-1 recomenda-se tamanho de amostra de 100 sementes.

Made available in DSpace on 2014-06-11T19:26:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-10Bitstream added on 2014-06-13T20:15:26Z : No. of bitstreams: 1 marques_dj_me_botfca.pdf: 1236525 bytes, checksum: b3e82023e001449560012288e4ba0ba8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A cultura da berinjela vem se destacando muito, principalmente na Europa, Estados Unidos e também no Brasil, com aumento da demanda por hortaliças. Dentre os fertilizantes potássios mais utilizados no Brasil, o cloreto de potássio, é responsável por 95% do consumo. Entre os fatores que afetam a resposta à adubação potássica, destacam-se salinidade e acidez do solo. O experimento foi divido em duas fases, sendo a primeira desenvolvida no Departamento de Produção Vegetal – Horticultura – UNESP, Campus de Botucatu, São Paulo. A segunda fase, compreendendo as análises bioquímicas, foram conduzidas no Departamento de Química e Bioquímica do Instituto de Biociências - UNESP, Campus de Botucatu, São Paulo. Utilizou-se a variedade de berinjela denominada de Embu, adotando-se delineamento em blocos casualizados, em esquema fatorial 2 x 4, com cinco repetições, com duas fontes de potássio (cloreto e sulfato de potássio) e quatro doses crescentes dos fertilizantes (250, 500, 750 e 1000 kg K2O ha-1) Observou-se que as plantas cultivadas com doses elevadas de ambas as fontes potássicas, induziram maior atividade das enzimas superoxido dismutase e catalase, além do aumento da concentração de L-prolina. Estas alterações indicam que estes parâmetros podem ser adotados como indicadores de estresse mineral na cultura da berinjela. Além dos fatores bioquímicos, observou-se que as variações das fontes potássicas influenciaram nos parâmetros biométricos e agronômicos da berinjela, notadamente quando aplicados em excesso. Avaliando-se os resultados do experimento, concluiu-se que a fonte KCl apresentou efeito salino superior, quando comparado com a fonte K2SO4 baseado no efeito mais pronunciado deste adubo, os parâmetros avaliados. Para ambas as fontes potássicas aplicadas, observou-se que o excesso de potássio afetou os parâmetros biométricos, produção e atividade enzimática das plantas. / Eggplant cultivation has extensively developed, mainly in Europe, United States and Brazil due to the increase in the demand for vegetables. Of the potassium fertilizers most frequently used in Brazil, potassium chloride satisfies 95% of the needs. Among the factors affecting the response to potassium fertilization are soil salinity and acidity. This experiment was divided into two steps: the first was conducted in the facilities of the Department of Plant Production, Horticulture, São Paulo State University – UNESP, Botucatu Campus, São Paulo State, Brazil. The second step which consisted of biochemical analyses was carried out in the Department of Chemistry and Biochemistry, Institute of Biosciences, UNESP, Botucatu Campus. The eggplant variety Embu was used, and the experimental design was in randomized blocks, 2 x 4 factorial arrangement, with five replicates, including 2 potassium sources (potassium chloride and sulfate) and four increasing doses of the fertilizers (250, 500, 750, and 1000 kg K2O ha-1). Elevated doses of both potassium sources led to higher activity of the enzymes superoxide dismutase and catalase in plants, as well as to an increasing L-proline concentration. Based on such alterations, those parameters can be used as indicators of mineral stress in eggplant culture. Besides biochemical factors, biometric and agronomical parameters were also influenced by variations in the potassium sources, mainly when applied in excess. The present experiment demonstrated that KCl source had higher saline effect, compared with K2SO4 source, considering the higher effect of the former on the evaluated parameters. As regards both potassium sources, the excess of potassium affected biometric parameters, yield and enzymatic activity.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Appropriate procedures for analyze the quality of seed is of fundamental importance, but are still incomplete in the quality control programs. The work was aims to standardize the methodology of the electrical conductivity mass and individual test and potassium leachate test to evaluate the vigor of rice seeds. It was used ten lots of rice seeds produced in the 2008/2009 crop, five the IRGA 424 variety and five Puita Inta CL variety.The lots were initially characterized the following determinations and tests: water content, germination test, first count, cold germination, length and biomass dry of seedlings and field emergence. For the electrical conductivity mass test variations were studied: number of seeds (25 and 50), water volume (50 and 75 ml), presence or absence of bark and immersion periods (1, 2, 4, 8, and 24 hours), temperature of 25 ºC. In the conductivity test individually survey the same periods of seeds immersion with and without bark, at a temperature of 25ºC and Seed Automatic Analyzer SAD 9000-S. It was also determined the amount of potassium leachate in the immersion solution, through flame photometer in different periods of immersion (30, 60, 90, 120, 150 and 180 minutes). It was concluded that the electrical conductivity mass test and individual is promising for the separation of lots of rice depending on the vigour of the seeds, but in the two ways of applying has influence the genotype used. For variety IRGA 424, the best conditions for the realization of the electrical conductivity mass test is the use of 25 seeds with bark, immersed in 50 or 75 mL of distilled and deionised water for 2 to 8 hours at 25ºC. For the evaluation of individual electrical conductivity the use of seeds with bark immersed for a period of 24 hours is appropriate. To the potassium leakage test the correct procedure to classify lots of rice seeds at function their physiological quality, is the combination 50 pure seeds submerged in 50 mL of distilled and deionized water at 25ºC for 60 minutes. / Procedimentos adequados para avaliar a qualidade de sementes embora de fundamental importância ainda são incompletos nos programas de controle de qualidade. O trabalho teve como objetivo estabelecer a metodologia do teste de condutividade elétrica massal e individual e do teste de lixiviação de potássio para a avaliação do vigor de sementes de arroz. Utilizaram-se dez lotes de sementes de arroz produzidos na safra 2008/2009, sendo cinco da cultivar IRGA 424 e cinco da cultivar Puitá Inta CL. Os lotes foram caracterizados inicialmente através das seguintes determinações e testes: teor de água, germinação, primeira contagem, frio sem solo, comprimento e massa seca de plântulas e emergência em campo. Para o teste de condutividade elétrica massal foram estudadas as variações: número de sementes (25 e 50), volume de água (50 e 75 mL), presença ou não de casca e períodos de imersão (1, 2, 4, 8, e 24 horas), na temperatura de 25 ºC. No teste de condutividade elétrica individual avaliaram-se os mesmos períodos de imersão em sementes com e sem casca, na temperatura de 25ºC, no Analisador Automático de Sementes. Determinou-se também, a quantidade de potássio lixiviado na solução de imersão, através de fotometria de chama em diferentes períodos de imersão (30, 60, 90, 120, 150 e 180 minutos). Concluiu-se que o teste de condutividade elétrica massal e individual é promissor para a separação de lotes de arroz em função do vigor das sementes, porém há influência do genótipo utilizado. Para a cultivar IRGA 424, a condição mais adequada para a realização do teste de condutividade elétrica massal é a utilização de 25 sementes com casca, imersos em 50 ou 75 mL de água destilada e deionizada, por 2 a 8 horas, à 25ºC. Para a condutividade elétrica individual o uso de sementes com casca imersas pelo período de 24 horas é o mais adequado. Para o teste de lixiviação de potássio a combinação de 50 sementes puras imersas em 50 mL de água destilada e deionizada, à 25ºC, durante 60 minutos representa o mais correto procedimento para classificar lotes de sementes de arroz, em função de sua qualidade fisiológica.

Made available in DSpace on 2014-10-09T12:27:47Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:54Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP