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The effect of physical, chemical and mineralogical properties on reducibility of iron containing raw materials were studied with the use of two pellets, one sinter and one lump iron ore sample provided by Erdemir integrated iron and steel works. Although Erdemir lump iron ore contained hematite, it was found to be less reducible than Erdemir sinter since porous structures are easier to reduce and in general sinters have a higher porosity as compared to lump ores. Experimental findings indicated that Erdemir pellet with a code B had the highest reducibility. On the other hand, the results of Erdemir samples were compared with those results obtained from the projects carried out in the Metallurgical and Materials Engineering Department of METU in 1980&rsquo / s. In mentioned projects, samples of various lump iron ores and a concentrate, pellet and sinter from Turkish sources and imported lump iron ores of CVRD from Brazil and ISCOR from the Republic of South Africa were tested. Within the context of this thesis, a mathematical model that would fit to the reduction kinetics was studied and the porous solid model was found to be the best for Erdemir samples.

Catalyst deactivation in single catalyst pellets and in an isothermal catalytic fixed bed reactor have been analytically studied. The work reported here is unlike the vast majority of previous theoretical analyses which are numerical. This thesis deals with two types of deactivation - parallel and series mechanisms in which respectively, reactant and product are directly responsible for poisoning. For the single particle studies, the principal analytical tools used are based on singular perturbation theory. Use of these techniques in the temporal domain depends crucially on the smallness of the ratio of the deactivation rate constant to that of the main reaction. Depending on the range of Thiele modulus, whether small, intermediate or large, three different techniques are used in the spatial domain. First, when the Thiele modulus is small, a lumping technique due to Frank-Kamentskii (1955) is used to replace the Laplacian operator by a suitable constant. This reduces the coupled partial differential equations to ordinary ones. Main chemical kinetics of n-th order and of Michaelis-Menten type are investigated. Second, when the Thiele modulus is very large, matched asymptotic expansions in the spatial domain are used. The analysis is based on the smallness of the inverse Thiele modulus, 1/phi2. A moving reaction zone of thickness 0(1/phi) is found to separate the dead shell from the active core of the catalyst pellet. The catalyst activity profile exhibits a sharp change within the reaction zone and the structure of this profile is found to be self-preserving during the period of its propagation. Solutions are obtained for three different geometries - planar, cylindrical and spherical. The large Thiele modulus results obtained here are found to be more accurate than the shell-model solutions of Masamune and Smith (1966) (except for a slab geometry, when they are identical). Finally, for an intermediate range of Thiele modulus, finite Sturm-Liouville integral transforms along with the concept of an effective average are successfully applied. The approach taken is novel, and although not rigorously justifiable, it leads to results of suprising accuracy. The versatility of the technique is demonstrated by application to various non-linear problems which posess exact solutions and remarkable agreement is found. The finite-cylindrical catalyst pellet is also investigated using a double-integral transform in the spatial domain and it is shown that for small Thiele modulus, the infinite cylinder and slab results are good approximations to finite length cylinders with small and large ratio, R/L, respectively. The analytical solutions reported in this thesis agree well with the known numerical results of others (Masamune and Smith, 1966; Khang and Levenspiel, 1973 and Lamba and Dudukovic, 1978). The parametric - dependence of these solutions is explicit and numerical results can be easily obtained from them by hand calculation. All the single pellet results are brought together in the final chapter and used to analyze the performance of isothermal fixed-bed reactors undergoing poisoning. Such effects as external mass transfer resistance, pellet shape and chemical kinetic type are included in the analysis, which embraces the entire range of Thiele modulus.

Zugl.: Braunschweig, Techn. Univ., Diss., 2007

Mycelial pellet formation by filamentous fungi is one of the most researched topics in fungal biotechnology research. Pellets are generally formed as a result of a complex interaction process through the influence of many cultivation factors such as inoculum size, pH, dissolved oxygen level, agitation system, nucleating agents, additives, trace metals, CO2, temperature, reactor types, carbon substrate, rheology, culture modes, fermenter geometry, nitrogen and phosphate levels etc. Each factor has varying effects on the growth morphologies of different fungal species. Fungal growths in the form of pellets have several advantages and pose a potential solution to overcome the problems associated with the filamentous fungal growth in large scale industrial bioreactors. The aim of the present work was to study pellet formation of edible filamentous fungus Neurospora intermedia, focusing on the molecular aspects of the fungal pellets with special interest to investigate the role of cell signaling second messenger cyclic 3', 5’-adenosine mono- phosphate (cAMP). It was found that Neurospora intermedia stimulate cAMP in the pellet form than filamentous form. The industrial applications of fungal pellets for generating value added products were also studied and observed fermentation in individual and co fermented first and second-generation ethanol substrate, showed an ethanol yield maximum of 0.25 ± 0.05 g/g dry substrate. The growth of fungal pellets in presence of inhibitors (such as acetic acid, HMF and furfural) resulted in about 11% to 45% increase in ethanol production as compared to filamentous forms, at similar growth conditions in the liquid straw hydrolysate.

Les nématodes gastro-intestinaux (NGIs) sont une contrainte majeure en élevage des ruminants au pâturage. La méthode de lutte usuelle est l’utilisation de traitements anthelminthiques (AH) de synthèse. Cependant, la diffusion constante de résistances aux AHs dans les populations de NGIs chez les petits ruminants impose de rechercher des méthodes alternatives de maitrise. L’exploitation de plantes contenant des métabolites secondaires est une de ces options. Le sainfoin (Onobrychis viciifolia), une légumineuse riche en tanins condensés (TCs), est un modèle pour explorer le concept de nutricament = fourrage associant valeurs nutritionnelles et propriétés sanitaires (AH). Récemment, une filière de production de granulés déshydratés de sainfoin (GDS) s’est construite. Les avantages en sont : cultiver le sainfoin dans les meilleures conditions agronomiques possibles, favoriser la standardisation et la caractérisation des lots avant usage pour assurer leur distribution en élevages voire leur exportation. L’objectif général de cette thèse a été de fournir les informations scientifiques pour favoriser l’utilisation de GDS en élevage de petits ruminants. Il s’est décliné en 3 axes de recherche : Le premier axe visait à valider des méthodes simples de dosage des tanins et de leur activité biologique, pour caractériser des ressources avant usage, en se fondant sur des mesures biochimiques (méthode colorimétrique de Folin- Ciocalteu) et d’activité biologiques (complexation des protéines = méthode de diffusion radiale et activité AH = méthode du dégainement larvaire imitant le processus d’infestation in vivo). Les corrélations entre les diverses mesures montrent un lien entre la quantité de TCs et l’activité AH ainsi que l’intérêt de la méthode NIRS pour caractériser les différentes sources de sainfoin (GDS et fourrages). Le second axe visait à mieux définir sur la base d’études en conditions expérimentales contrôlées, les conditions optimales d’application des GDS en élevage. Une première série d’études a cherché à explorer 1) les effets AH combinés, liés à la concentration en TCs dans la ration et à la durée de distribution, contre divers stades (L3, vers adultes) d’espèces abomasales ou intestinales et 2) l’intérêt d’associer le sainfoin avec un AH de synthèse. Les résultats montrent 1) qu’un seuil minimum de TCs dans la ration doit être atteint et une période minimum de 15 jours de distribution est nécessaire pour altérer la biologie des nématodes (notamment la fertilité des vers femelles de Trichostrongylus colubriformis et le nombre d’Haemonchus contortus) et 2) qu’une utilisation dissociée d’un AH de synthèse (ivermectine par voie orale) est préférable en raison d’interactions négatives. Le dernier axe a visé à comparer la capacité d’ovins ou de caprins à moduler leur comportement alimentaire vis-à-vis de GDS en fonction de leur état parasitaire (capacité d'automédication). L’objectif était de vérifier les hypothèses suivantes : compte-tenu de leur moindre résistance envers les parasites et une plus grande propension à consommer des tanins, les caprins consommeront plus de sainfoin que les ovins ; les animaux fortement parasités exprimeront une préférence pour le sainfoin, et celle-ci augmentera au cours du temps. Les résultats de cet essai ont montré, dans le test de cafétéria, que 1) les chèvres préféraient le sainfoin et 2) une augmentation de la consommation en sainfoin au cours du temps chez les animaux parasités, sans toutefois devenir supérieure à celle des animaux sains. En revanche, ni les animaux parasités, ni les caprins n’ont montré de motivation plus importante pour obtenir la ressource riche en tanins dans le test de conditionnement opérant. Ces résultats montrent l’intérêt de l’utilisation de granulés de sainfoin en élevage, afin de compléter les AHs de synthèse et limiter le développement des résistances à ces molécules chez les NGIs. / Gastrointestinal nematodes (GINs) represent a major threat for grazing ruminants. The traditional mode of control of these parasites mainly relied on the use of synthetic anthelmintics (AHs). However, the repeated use of these molecules has led to resistance against all AH drugs in worm populations of small ruminants. Alternative solutions are needed. Among those, the use of plants that contain plant secondary metabolites, such as condensed tannins (CTs), has been studied for the last 20 years. These CT-containing resources, such as sainfoin (Onobrychis viciifolia) have AH properties and beneficial effects on health and also interesting nutritional values; hence they correspond to the definition of nutraceuticals. Recently, an organization has developed to produce dehydrated pellets of sainfoin. The advantages of such pellets are 1/ to grow sainfoin in the best agronomic conditions; 2/ to better standardize the product; 3/ to evaluate the pellet before use and to facilitate exportation. The general aim of this thesis was to optimize the use of sainfoin pellets in farm conditions. Our first objective was to characterize the CT content and AH properties of sainfoin pellets. For industrial purposes, simple, low cost and repeatable methods to evaluate the CT content and the AH activity are requested in order to rapidly qualify the pellets. The CT content was evaluated by biochemical measurements of total phenols and tannins (Folin-Ciocalteu). This was completed by the measure of the complexation of tannins with proteins (Radial Diffusion) and by development of prediction calibrations using near infra-red spectroscopy (NIRS). The AH evaluation was performed on samples before and after dehydration, using the Larval Exsheathment Inhibition Assay. Calculations of correlations between the different methods showed significant links between the quantity of CT and the AH activity, and the possible use of NIRS to measure the CT content and the AH activity of pellets and forages. The second objective aimed at defining the optimal conditions to use sainfoin pellets on farm, to improve the AH activity. We aimed at analyzing, in experimental conditions, 1) how the combination of 2 factors, namely the CT concentration in feed and the length of distribution, influence the AH efficacy of sainfoin pellets on intestinal and abomasal L3 larvae or adult worms; 2) whether or not the combined use of sainfoin with a chemical AH (oral ivermectine) is beneficial. Results showed that a minimum CT content in sainfoin and a minimum length of distribution of 15 days are mandatory to alter the adult worm and L3 larvae biology of nematodes, particularly the Trichostrongylus colubriformis fertility and the number of Haemonchus contortus. Moreover, the combined use of AH and sainfoin consumption should be avoided because of negative interactions. The last axis aimed at studying the behavior of sheep and goats in relation to sainfoin pellets and their ability to change the feeding behavior according to their parasitic status (self-medication ability). The objective was to verify the following hypotheses: due to their lower resistance against parasites and their higher propensity to eat CTs, goats will eat more sainfoin than sheep, parasitized animals will prefer sainfoin and this preference will increase overtime. The results showed that two of our hypothesis were verified in a cafeteria study: 1) goats preferred sainfoin while sheep preferred alfalfa and 2) the sainfoin consumption increased overtime for infected animals, without being higher than nonparasitized ones. However, nor goat, nor parasitized animals, showed a higher motivation in the operant-conditioning trial to feed on CT rich resources. All the present results showed the interest to exploit sainfoin pellets in farms, as one alternative to AHs molecules in order to limit the development of resistances to these drugs in GIN populations.

Submitted by dayse paz (daysepaz@hotmail.com) on 2016-04-06T14:41:40Z No. of bitstreams: 1 Diserta_o_Vanessa_Brito.pdf: 1599477 bytes, checksum: 07d436c3a3d3c4454a7866d4dfa32c22 (MD5) / Approved for entry into archive by cleuza maria medina dos santos (cleuzamai@yahoo.com.br) on 2016-04-07T00:06:42Z (GMT) No. of bitstreams: 1 Diserta_o_Vanessa_Brito.pdf: 1599477 bytes, checksum: 07d436c3a3d3c4454a7866d4dfa32c22 (MD5) / Made available in DSpace on 2016-04-07T00:06:42Z (GMT). No. of bitstreams: 1 Diserta_o_Vanessa_Brito.pdf: 1599477 bytes, checksum: 07d436c3a3d3c4454a7866d4dfa32c22 (MD5) Previous issue date: 2013 / O presente trabalho investigou a dieta de Platalea ajaja (colhereiro) e Ardea alba (garça-brancagrande), em 2011/2012, em um ambiente límnico (banhado do Aguirre) e outro estuarino na Lagoa dos Patos (ilha dos Marinheiros), Rio Grande, RS, no sul do Brasil. Foram analisados regurgitados espontâneos, conteúdos gastrointestinais, pellets, lavagem estomacal e isótopos estáveis. Os itens alimentares mais importantes na caracterização direta da dieta de P. ajaja no estuário foram os insetos (PSIRI% = 47,2), seguido de crustáceos (PSIRI% = 30,4) e peixes (PSIRI% = 12,6). No ambiente límnico P. ajaja teve uma dieta com predomínio de insetos (PSIRI% = 59,9), seguido de peixes (PSIRI% = 19,8). No estuário a dieta de A. alba foi predominantemente piscívora (PSIRI% = 53,3), seguido em importância pelos crustáceos (PSIRI% = 30,8). Entretanto, no ambiente límnico A. alba teve os insetos como item alimentar principal (PSIRI% = 58,9), seguido de peixes (PSIRI% = 27,9). Sangue de filhotes com mais de três semanas de vida e presas/alimentos potenciais tiveram os isótopos estáveis de carbono (δ 13C) e nitrogênio (δ 15N) analisados. No ambiente límnico A. alba apresentou valores médios de δ 15N semelhantes a P. ajaja límnico, diferenciando-se de A. alba e P. ajaja estuarinos. Os valores médios de δ 13C nas duas espécies e locais foram semelhantes, porém menor em sangue de A. alba estuarina. O modelo linear generalizado (GLM) explicou 44% na variação dos dados de δ 15N, diferindo entre os locais e influenciado pelo tamanho do filhote. O GLM com os valores de δ 13C explicou 22% da variação nos valores, indicando que A. alba alimenta os filhotes com outros itens alimentares dependendo do local, enquanto os filhotes de P. ajaja possuem uma alimentação límnica nos dois ambientes. Os modelos bayesianos de misturas de isótopos (SIAR) indicaram presas límnicas para P. ajaja nos dois ambientes, corroborando os resultados do GLM e dos métodos de estudo de dieta tradicionais. Portanto, A. alba utiliza as áreas próximas ao local de reprodução para se alimentar, não apresentando preferência por área de forrageamento estuarino ou límnico. Em ambiente límnico as duas espécies podem utilizar recursos alimentares semelhantes, enquanto no ambiente estuarino a sobreposição na dieta diminui, por alimentaremse em diferentes locais e distintos itens alimentares. Através de diversas metodologias verificouse que P. ajaja alimenta-se de presas límnicas, apesar de reproduzir-se em ambos os ambientes, enquanto A. alba alimenta-se de presas límnicas e estuarinas dependendo do local onde ocorre sua reprodução. / This study investigated the diet of Roseate spoonbills (Platalea ajaja) and Great egrets (Ardea alba) in 2011/2012, in two colonies, one in a freshwater (Aguirre marsh) and another in the Lagoa dos Patos estuary (Marinheiros island), both in Rio Grande municipality, Rio Grande do Sul state, southern Brazil. Spontaneous regurgitations, gut contents, of dead chicks, pellets, stomach flushing and stable isotopes of chicks were analysed. The most important prey items for estuarine spoonbills were insects (PSIRI% = 47.2), crustaceans (PSIRI% = 30.4) and fish (PSIRI% = 12.6). In the freshwater colony, spoonbills had diet composed mostly by insects (PSIRI% = 59.9) and fish (PSIRI% = 19.8). In the estuary, egrets had a predominantly piscivorous diet (PSIRI% = 53.3), followed in importance by crustaceans (PSIRI% = 30.8). However, in the freshwater colony egrets had insects as the main food items (PSIRI% = 58.9), followed by fish (PSIRI% = 27.9). Blood of chicks over three weeks and tissues of potential food items had stable isotopes of carbon (δ 13C) and nitrogen (δ 15N) analised. In the freshwater environment, egrets had mean δ 15N values similar to freshwater spoonbills, but different from egrets and spoonbills from the estuarine site. Mean values of δ 13C in both places and sites were similar, but higher in estuarine egrets. A generalized linear model (GLM) explained 44% in the variation in δ 15N values, differing between sampling sites and influenced by chick size. The GLM on δ 13C values explained only 22% in data variation, suggesting that egrets feed their chicks with different prey items, depending on the place where the colony is placed. On the other hand, spoonbills had limnetic feeding only, no matter the place where they are breeding. Bayesian stable isotope mixing models (SIAR) indicate that limnetic prey were important for spoonbill chicks in both colonies, in line with GLM analysis and dietary data using traditional methods. Therefore, egrets forage in areas near breeding places, without preferences for freshwater or estuarine habitats. In the freshwater colony egrets and spoonbills could rely on similar feeding resources, while in estuarine environments competition seems to be relaxed by feeding on different places and prey items. By using different methodologies it was possible infer that spoonbills feed on freshwater food items, no matter where they breed, while egrets use both limnetic and estuarine food items, depending where the colony is placed.

A bacia hidrogrÃfica do Rio Jaguaribe, localizada no Estado do CearÃ, ocupa uma Ãrea de em torno de 80.000 km2, a sub-bacia do Baixo Jaguaribe tem Ãrea de drenagem de 6.875 km2, sendo esta correspondente a 4,64% do territÃrio cearense. A regiÃo estuarina do Rio Jaguaribe à dominada por florestas de manguezal que ocupam 215,5 ha, particularmente no canal de marà da Gamboa do Cumbe. Estando na regiÃo Ãrea implantada a maior Ãrea de produÃÃo de camarÃo em cativeiro do estado, ocupando 1.316 ha em viveiros cerca de 50% do total de todo o Estado do CearÃ. A quantificaÃÃo de mercÃrio (Hg), na Ãgua e em sedimento (superficial e testemunhos sedimentares) ao longo de toda a Gamboa do Cumbe mostrou valores variando de 6,3 a 32,1 ng/l (14,4  8,4), 1,1 a 23,5 ng/l (7,0  7,8), 3,2 a 15,0 ng/l (7,4  3,9), para o Hg total, dissolvido e particulado na Ãgua respectivamente. No sedimento as concentraÃÃes variaram de 1,6 a 10,3 ng/g (4,7  2,9) e 1,9 a 16,2 % (6,7  4,9) respectivamente para a concentraÃÃo de Hg e percentual de matÃria orgÃnica. A concentraÃÃo de Hg em peixes coletados na regiÃo variaram de 4,3 â 37,0 ng/g (9,9  9,0) em Sphoeroides testudineos e 9,7 a 66,1 ng/g (31,8  14,4) Cathorops spixii. Com a obtenÃÃo destes dados pÃde-se definir a Ãrea preferencial de deposiÃÃo e acumulaÃÃo de Hg e a forma dissolvida mostrou-se a predominante exportada. Aquacultura promove alteraÃÃes significativas das cargas de Hg nos Ãltimos anos baseado nos valores da concentraÃÃo de Hg nos perfis sedimentares. O Hg proveniente da aquicultura à 156,4 kg.ano-1, na sua maioria associados ao MPS sendo transportado para a regiÃo estuarina adjacente e depositado na Ãrea da Gamboa do Cumbe. / The Jaguaribe River basin, located in State CearÃ, occupies an area of about 80,000 km2, wher as the sub-basin of the Lower Jaguaribe River has a drainage area of 6,875 km2, equivalent to 4.64% of the stateâs area. The estuarine region of the Jaguaribe River is dominated by mangrove forests that occupy 215.5 ha, particularly in the tidal channel of the Gamboa do Cumbe. In this area it is located the largest area of shrimp production in captivity in the state, with 1,316 ha of pond area around 50% of the entire aquaculture area of the state of CearÃ. The quantification of mercury (Hg) in water and sediments (surface and sedimentary profile) along the Gamboa do Cumbe showed values ranging from 6.3 to 32.1 ng / l (14.4  8.4) , 1.1 to 23.5 ng / l (7.0  7.8), 3.2 to 15.0 ng / l (7.4  3.9), or total Hg, dissolved and particulate Hg respectively. In sediments concentrations ranged from 1.6 to 10.3 ng / g (4.7  2.9) and 1.9 to 16.2% (6.7  4.9) for Hg and organic matter respectively. The concentration of Hg in fish collected in the region ranged from 4.3 to 37.0 ng / g (9.9  9.0) in Testudines sphoeroides and from 9.7 to 66.1 ng / g (31.8  14 , 4) in Cathorops spixii. These data made possible to define the area of preferential deposition and accumulation of Hg and that the predominant form of Hg export is dissolved Hg. Aquaculture, seems to have promoted significant changes in Hg loads in recent years based on records of Hg concentration in sedimentary profiles. Hg of burden from aquaculture to the region is about 156.4 kg.ano-1, mostly associated with TSS transported of the adjacent estuarine region and is stored in the sediment of the deposition area of Gamboa do Cumbe.

Um injetor de pastilhas (pellets) de impurezas foi projetado, construído e instalado junto ao tokamak TCABR do Instituto de Física da Universidade de São Paulo - USP. O injetor é basicamente constituído por uma câmara com gás a alta pressão cuja vazão é controlada por uma bobina de acionamento rápido. Uma fonte de alta tensão (7kV) e alta corrente (6kA) foi construída para alimentar a bobina. Ao ser disparada, o gás propulsor (N2 ou He) acelera a pastilha para o interior do vaso do tokamak, sem que gás penetre no mesmo. Pastilhas de grafite cilíndricas com diâmetro de 0,4mm a 0,9mm, e comprimento de 0,5mm a 1mm, foram utilizadas para investigar a possibilidade de se mitigar os e*feitos de uma disrupção maior O processo de ablação da pastilha no TCABR foi investigado através de simulações que consideraram, de uma maneira simplificada, o resfriamento sofrido pelo plasma devido à propagação da pastilha no seu interior. O modelo, ao ser aplicado aos dados experimentais do tokamak T-10, por exemplo, apresentou resultados bastante encorajadores. Na maioria dos casos em que houve a injeção das pastilhas no TCABR, o plasma terminou devido ao surgimento de uma disrupção maior. Analisando a taxa de queda da corrente de plasma em dois instantes próximos ao fim da descarga, tanto para pulsos que sofreram uma disrupção natural quanto aos que sofreram um disrupção induzida (devido à injeção de pastilhas de grafite), constatou-se que a corrente de plasma decresce mais lentamente nos casos em que houve o disparo do injetor. Isto significa uma menor sobrecarga nos sistemas eletro-mecânicos do tokamak, em resultado à ocorrência da disrupção. A análise da atividade MHD foi realizada no entorno da disrupção causada pela injeção de pastilha. Observou-se, em conseqüência, uma redução da velocidade de rotação das ilhas magnéticas após o início da interação da pastilha com o plasma. Também constatou-se, em todos os disparos analisados, um aumento significativo da atividade MHD. Um outro resultado interessante foi a constatação de que a emissão de raios-X de altas energias decresce significativamente no final das descargas nas quais ocorre a injeção de pastilhas. / An impurity pellet injector has been projected, built and installed in the TCABR tokamak, at the Physics Institute of Physics of the University of São Paulo - USP. Basically, the injector is composed of a high pressure gas chamber, in which the gas flow (N2 or He) is controlled by a fast switch valve. An high voltage (7kA) and high electric current (6kA) power supply has been built to provide energy for the valve. When fired, the propellant gas move the pellet into the interior of the tokamak vessel. During this process, the gas is properly collected before reaching the tokamak vacuum chamber. For this work, cylindrical carbon pellets with 0,4mm to 0,9mm in diameter and 0,5mm to 1mm in length were chosen as to investigate how the hazardous effects of a major disruption could be mitigated. The pellet ablation process in TCABR was studied trough running simulations that take into account, in a simplified way, the cooling of the plasma by the propagating pellet. The model, when applied to the T-10 tokamak experimental data, for example, exhibited very encouraging results. For the TCABR tokamak, in most of the cases in which pellets were injected, the plasma was terminated because of the advent of a major disruption. By analyzing the plasma current decay rate in two time intervals - within the end of plasma discharges, with and without the injection of pellets, it was observed that the plasma current decays significantly slower when pellets are injected. Consequently the load on the tokamak\'s electromechanical systems is reduced. Fourier analysis has been carried out to investigate the MHD activity near the disruption time, caused by the pellet injection. It could be noticed a reduction on the magnetic island\'s velocity rotation, after the pellet-plasma interaction initiates. Also, for all discharges analyzed, the MHD activities increased in amplitude after the pellet-plasma interaction. Another interesting result refers to the fact that the hard X-ray emission was observed to decrease significantly within the end of discharges in which pellets were injected

The diploma thesis deals with optimization of pellet boiler for agropellets combustion. On the Czech market are mostly available boilers for burning wood pellets. Specially adapted agropellet boilers are pretty expensive. The work is divided into two main parts. The first part contains a research of agropellets, agropellets production and combustions of agropellets. The second part is experimental and describes the combustion test. It describes the measurement procedure, the necessary calculations and evaluation.