Le but de cette étude est d’explorer la possibilité d’utiliser trois argiles dans l’industrie céramique locale au Sénégal. Une argile rouge (NM) et deux argiles grises (MN1) et (MN2) proviennent respectivement de la région de Ziguinchor à Néma et de Tambacounda à Malème Niani. L'étude concernant les caractéristiques physico-chimiques des argiles, indique que les compositions chimique et minéralogique contiennent la présence de quartz, de kaolinite, d’illite, de montmorillonite et de goethite. Leurs caractéristiques structurales et leurs surfaces spécifiques sont similaires. Leur caractéristiques minéralogiques mènent à un classement dans les groupes des argiles kaolino-illite ou kaolino-smectique. Par des analyses thermiques, les températures de transformations thermiques caractéristiques des phases ont été bien identifiéesLa mise en forme par pressage uniaxial des poudres humidifiées et granulées de ces argiles a été optimisée. Les propriétés d’usage des produits frittés ont été mesurées indiquant que les propriétés mécaniques sont limitées, bien que la mullite et la cristobalite constituent les phases minérales majoritaires des microstructures. La porosité a été mesurée après frittage à différentes températures (1000°C, 1100°C et 1200°C), variant de 25% à 30% et diminuant peu avec l’augmentation de la température de frittage. Dans l’ensemble, les résultats révèlent que ces argiles prises à l’état brut nepossèdent pas toutes les caractéristiques satisfaisantes pour la production de briques et tuiles. Pour améliorer les propriétés mécaniques, une substance éco-durable organique, le Cola Cordifolia, a été ajoutée aux argiles. Cet additif induit une augmentation de 28% de la résistance mécanique de l’argile rouge (NM) après cuisson à 1000°C, atteignant la valeur minimale de la norme concernant les briques. Finalement, d’autres pistes d’amélioration des propriétés d’usage ont été explorées telles que l’ajout de l’urée et de fondants potassique et sodique. Ces ajouts ont permis d’accentuer la densification des matériaux de terre cuite pour la production de briques. / The aim of this study is to explore the possibility of using three clays for the local ceramic industry in Senegal. We used a red clay (NM) and two gray clays (MN1) and (MN 2) from the region of Ziguinchor in Nema and Tambacounda in Niani Maleme, respectively. The study of the physicochemical characteristics of clays indicates that the chemical and mineralogicalcompositions contain the presence of quartz, kaolinite, illite, montmorillonite and goethite. Their structural characteristics and their surface areas are similar. Their mineralogical characteristics lead to a classification in groups of Kaolino-illite clays or Kaolino-smectite. By thermal analysis, typical phase transformation temperatures were well identified. The shaping by uniaxial pressing of moistened and granulated powders of clays was optimized. The properties in use of the sintered products were measured indicating that the mechanical properties are limited, although cristobalite and mullite constitute the major mineral phases in microstructures. Porosity was measured after sintering at different temperatures (1000°C, 1100°C and 1200°C), ranging from 25% to 30% and with a little lowering with increasing the sintering temperature. Overall,results indicate that these clays do not attain satisfactory characteristics for the production of bricks. To improve the mechanical properties, an organic eco-sustainable substance, the Cola Cordifolia, has been added to clays. This additive induces a 28% increase of the mechanical strength of the red clay (NM) after firing at 1000°C, reaching the minimum value of the standard for bricks. Finally, other areas for improvement of properties in use were explored such as the addition of urea and potassium or sodium fluxes. These additions have helped the increase of densification of clay materials for the production of bricks.

Drought conditions and wildfires can induce soil water repellency. Precipitation shifts are expected to exacerbate drought and wildfire in regions such as the southeastern United States, making it critical to understand how repellency affects water exchange processes in soil. The objectives of this dissertation were to 1) quantify the water vapor sorption dynamics of two clay minerals in which water repellency was induced; 2) identify if and for how long wildfires in humid hardwood forests induce water repellency, 3) evaluate if organic carbon content and hydrophobic functional groups explain actual and potential soil water repellency; and 4) understand how vertical position (i.e., depth) of water repellent layers affect infiltration processes. To meet these objectives, a laboratory test was first conducted examining water vapor sorption processes in water-repellent clay minerals. Next, a field study occurred in two forests that experienced wildfires in late 2016: Mount Pleasant Wildfire Refuge, Virginia, and Chimney Rock State Park, North Carolina, United States. Measurements include water drop penetration time, soil water content, and tension infiltration. Complimentary laboratory tests quantified potential soil water repellency, soil organic carbon content and hydrophobic functional groups. Results showed that water repellency inhibited water vapor condensation because of altered mineral surface potentials and decreased surface areas. Burned hardwood forest soils presented water repellency for > 1 year, though laboratory measurements presented different trends than in situ measurements. Total organic carbon content and hydrophobic functional groups correlated with soil water repellency measured in the laboratory but not the field. Soil water content was lower in burned than unburned soils, and negatively correlated with water repellency. Water repellency in the surface layers significantly reduced relative water infiltration rates, whereas subsurface water repellency did not, and water repellency persisted longer in sites with surface compared to subsurface water repellency. Finally, while the wildfires increased the occurrence of water repellency, they did not alter the underlying relationship between relative infiltration and surface water repellency. Altogether, this study provided new insight into water repellency effects on water partitioning at soil-atmosphere interfaces, and presented evidence of soil and hydrological changes induced by wildfires in humid hardwood forests. / PHD / Rising temperatures and shifting precipitation patterns that result from global climate change have the potential to induce long-term droughts, which may induce soil water repellency, as can wildfires that become more prevalent and damaging. Water repellency can alter the physical, chemical, and hydraulic properties of soil. These alterations may drive soil erosional processes and increase the mobility of surface-bound pollutants with the potential to reduce water quality and degrade down-gradient aquatic ecosystems. Thus, it is critical to understand how water repellency affects water movement in and through soils. Despite several decades of research towards this topic, some critical questions still remain. For example, how does water repellent soil influence water characteristics in the vapor phase (which is increasingly important under drought conditions)? Do wildfires in humid hardwood forests cause soil water repellency? If so, how long does water repellency persist? Do water repellency measurements using field and laboratory techniques correspond to one another? How does the depth of water repellent soil layer(s) affect water movement? In order to solve this questions, several tests were conducted in both field and laboratory. The field experiments occurred within forested hillslopes that underwent varying degrees of burning during widespread wildfires that affected the Southeastern United States in late 2016. Choosing two forested locations, we measured actual water repellency, soil moisture, and infiltration in burned and unburned sites after wildfire, and took loose samples for laboratory tests. In the lab, we tested potential water repellency on air-dried soil samples, soil organic carbon content and hydrophobic substance percentage. We also conducted water vapor sorption experiments to quantify water vapor exchange in two types of water repellent minerals: kaolinite and montmorillonite. The results showed that water repellency can affect water exchange between the subsurface and the atmosphere, by both limiting water vapor sorption and reducing liquid water infiltration. Soil organic matter and composition correlate well with potential water repellency measured in the laboratory, though less so with actual water repellency measured in the field. Instead, soil water content provided a high and inverse correlation with actual water repellency. Finally, water infiltration rates were influenced by the vertical position (depth) of water repellent layers, with water repellency at the soil surface causing much reduced initial infiltration rates compared to water-repellent layers in the subsurface.

Made available in DSpace on 2016-05-02T13:55:26Z (GMT). No. of bitstreams: 1 Dissertacao Gil de Faria Leite.pdf: 336555 bytes, checksum: 5bce80b556395bba02077aed101a07d2 (MD5) Previous issue date: 2005-02-18 / The present research was conducted at Fazenda Porto Alfenas-MG with purpose of determining the effect of doses of liquid swine dejections on sugarcane productivity and concentration of nutrient in the soil Two types of fertilization were tested in a second-cut sugarcane plantation variety SP 81-3250 in dark red dystrophic latosoil (LVEd): (1) liquid dejections of swines were used in the doses of 0 40 80 120 160 and 200 m³/ha and applied all at once and (2) conventional chemical fertilization The research design was the randomized blocks with four repetitions For comparison averages the SISVAR program and Scott-Knott test were used The harvest was made one year after the experiment implantation The agricultural productivity and technology quality of sugarcane were determined The dose of 40 m³/ha was equivalent to chemical manuring while the others showed 76,5% - 96,3% higher productivity when compared to the witness plantation (58,10t/ha) No statistical difference was found with regard to the technological quality of stalks The liquid swine dejections provided significant increases in the sugarcane stalk productivity without jeopardizing the technological quality The concentration of nutrients in the soil was observed after the harvest No differences were observed the concentrations of phosphorus calcium copper zinc and organic matter The concentrations of magnesium and potassium changed in the 0 20 and 20 40 cm layers of the soil / A pesquisa foi conduzida na Fazenda Porto Município de Alfenas-MG cujo objetivo foi determinar o efeito da dosagem de dejetos líquidos de suínos na fertilização da cana-de-açúcar e a concentração de nutrientes no solo Utilizaram-se dejetos líquidos de suínos nas dosagens de 0 40 80 120 160 e 200 m³/ha aplicados em uma vez e adubação química convencional em uma lavoura de cana-de-açúcar de 2º corte variedade SP81-3250 em Latossolo vermelho escuro distrófico (LVEd) O delineamento utilizado foi o de blocos casualizados com quatro repetições Para comparação de médias utilizou-se o programa SISVAR e o teste de Scott-Knott A colheita foi feita um ano após a implantação do experimento (julho 2004) Foram determinadas a produtividade agrícola a qualidade tecnológica dos colmos da cana-de-açúcar e as concentrações de nutrientes no solo A dosagem de 40 m³/ha equivaleu à adubação química sendo que as demais apresentaram produtividades agrícolas superiores de 76,5% a 96,3% maiores que a testemunha que foi de 58,10t/ha Quanto à qualidade tecnológica dos colmos não foi verificada diferença estatística Apenas a concentração de Mg e Zn alteram nas camadas de 0 a 20 e 20 a 40 cm de profundidade respectivamente Concluiu-se que os dejetos líquidos de suínos proporcionaram aumentos significativos na produtividade de colmos da cana-de-açúcar sem comprometer a qualidade Os dejetos líquidos de suínos alteraram as concentrações do magnésio e zinco nas camadas de 0 a 20 e 20 a 40 cm solo respectivamente

(EN) A plasma torch (the source of plasma) with Gerdien arc was utilized as the source of energy in a reactor for gasification of biomass and for the degradation of organic compounds dissolved in water circling around the arc where the dissolved compounds are exposed to an intensive ultraviolet radiation. Thermal plasmas have electrons, ions and neutrals in thermal equilibrium and are quite often characterized by higher pressures and temperatures than nonthermal plasmas. Therefore, thermal plasmas generally carry a huge amount of energy which can be employed for heating and subsequent gasification of various types of materials. Thermal plasma gasification reactors are operated at higher temperatures than conventional reactors which results in a very good composition with a high percentage of hydrogen and carbon monoxide in produced synthetic gas. Spruce sawdust and spruce pellets were gasified at feeding rates up to 60 kg/h. Oxidizing media such as water, carbon dioxide, oxygen or their mixtures had to be added to the reactor during experiments to avoid the formation of solid carbon. The compositions of produced gas significantly corresponded to calculated compositions and the produced gas was of high quality - hydrogen content approximately 45 % vol., carbon monoxide approximately 48 % vol., a...

The great agricultural potential of Brazil is recognized internationally, occupying the position of producing greater of sugarcane of the world. The projected growth for production of sugarcane in the country will imply in the generation of great volume of the residues for the sugarcane industry, that if made use inadequately can cause great damages to the environment. On the other hand, these same residues can be used as source of nutrients, reducing the ambient contamination and the costs with fertilization. However, few studies exist on the amount and form of application of these residues in sugarcane-beats. The filter cake, one of the residues of the sugarcane industry, is presented as excellent organic product for the recovery of ground and with low fertility, as well as, for the supply of nutrients. The present research was carried through in ground of argillaceous texture, an area of commercial farming with system of conventional plantation and without irrigation, having for objective to evaluate the morphologic, technological, and productivity characteristics of the sugarcane (3rd raton) for different forms of application and dosage of filter cake. The experiment was installed using the experiment delineation of blocks design with ten (10) treatments and five (5) repetitions, in 5 factorial project X 2 + 1 that they correspond the 5 increasing dosage of filter cake (0, 10, 20, 40 and 80 t ha-1) combined the 2 ways of application (in the superficial line and the one between incorporated line) and a corresponding additional treatment to a mineral fertilization. The variety of the sugarcane used in the experiment was the SP 81-3250 with average cycle and demanding in fertility of the ground, being its plantation carried through in October of 2000. The experiment was after installed 3º cut of the canavial in September, 11 of 2003 and (4º cut of the canavial) in June, 28 of 2004. Were had been evaluated number of sptout for hectare to the 60 and 120 days after the installation of the experiment, average height and average diameter of sugarcane stalks (m), Brix of the broth (%), POL of the sugarcane (%), productivity of sugarcane for hectare and productivity of sucrose for hectare. The gotten results had shown that it had difference statistics for number of sptout for hectare in the interaction between application way and time of sampling. Significant difference was not observed, in none of the evaluated variable, for the different ways of application of the filter cake. The different dosage of applied filter cake had presented significant difference for height of sugarcane stalks, Brix, POL, TCH and TPH. From the results presented in this study, it was concluded that the filter cake application presented effect positive on sugarcane stalks, exactly in the dosage of 10 t ha-1, independently in the application way. / O Brasil é o maior produtor de cana-de-açúcar, açúcar e etanol do mundo, o que implica na geração de grande volume de subprodutos pela indústria sucroalcooleira, destacando-se o bagaço, a torta de filtro e a vinhaça. A torta de filtro, apresenta-se como excelente produto orgânico para a recuperação de solos exauridos e com baixa fertilidade, bem como, para o fornecimento de nutrientes. Entretanto, existem poucos estudos sobre a quantidade e forma de aplicação desse subproduto em cana soca. A presente pesquisa foi realizada em solo de textura argilosa, numa área de lavoura comercial com sistema de plantio convencional e sem irrigação, e teve por objetivo avaliar a produtividade e características morfológicas e tecnológicas da cana-de-açúcar (3ª soca) para diferentes formas de aplicação e doses de torta de filtro. O experimento foi instalado utilizando-se o delineamento experimental de blocos ao acaso (DBC) com onze (11) tratamentos e cinco (5) repetições, em esquema fatorial 5 X 2 + 1 que correspondem a 5 doses crescentes de torta de filtro com 71,4 % de umidade (0, 10, 20, 40 e 80 t ha-1) combinadas a 2 modos de aplicação (na linha superficial e na entre linha incorporada) e um tratamento adicional correspondente a uma adubação mineral. A variedade da cana-de-açúcar utilizada no experimento foi a SP 81-3250 de ciclo médio e exigente em fertilidade do solo, sendo seu plantio realizado em outubro de 2000. O experimento foi instalado após o 3º corte do canavial, em 11 de setembro de 2003, e colhido (4º corte do canavial) em 28 de junho de 2004. Foram avaliados número de perfilhos por hectare, aos 60 e 120 dias após a instalação do experimento, altura e diâmetro médio de colmos (m), Brix do caldo (%), POL da cana (%), produtividade de colmos por hectare (TCH) e produtividade de sacarose por hectare (TPH). Os resultados obtidos mostraram que houve diferença estatística para número de perfilhos por hectare na interação entre modo de aplicação e época de amostragem. Não foi observado diferença significativa, em nenhuma das variáveis avaliadas, para os diferentes modos de aplicação da torta de filtro. As diferentes doses de torta de filtro aplicadas apresentaram diferença significativa para altura de colmos, Brix, POL, TCH e TPH.. A partir dos resultados apresentados neste estudo concluiu-se que a aplicação de torta de filtro apresentou efeitos positivos sobre a cana soca, mesmo na dose de 10 t ha-1, independentemente do modo de aplicação. / Mestre em Agronomia

Esta dissertação tem como objetivo, a apresentação de uma proposta para os resíduos agroextrativistas a fim de encontrar um composto orgânico ideal para ser utilizado na agricultura do Município de Laranjal do Jari, no Estado do Amapá. A técnica em questão será a compostagem, gerando uma alternativa de utilização para os resíduos de natureza local, onde atualmente não vêm sendo aproveitados. Para se chegar ao composto ideal serão utilizados basicamente: caroços de açaí e cascas de castanha. Esses resíduos vêm sendo relegados através dos Serviços de Limpeza Pública, constituindo não só um problema estético ou ambiental, mas de desperdício de energia e materiais que poderiam ser utilizados na recuperação de áreas degradadas ou como composto orgânico, na fixação de nutrientes e água no solo a fim de melhorar as práticas agrícolas, reduzir custos e a importação de fertilizantes químicos. A metodologia envolve estudo bibliográfico sobre a técnica de compostagem, consistindo em desenvolver todas as etapas que se darão mais claras, no desenvolver dos trabalhos de campo, para uma futura implantação de uma Unidade de Compostagem, a ser aplicável para a agricultura do referido município. / This work has the objective, to present a proposal for the agriculture-extractive residues to find an organic compound ideal for use in agriculture of the Laranjal do Jari, in the state of Amapá. The technique in question will be composting, generating an alternative to use for the residues of local nature, where currently they do not come being used to advantage. To arrive itself at the ideal composition they be used basically: açaí seeds and chestnut rinds. These residues came being relegated through the Services Public Cleaning, constituting not only an aesthetic or environmental problem, but of wastefulness of energy and materials that could be used in the recovery of degraded areas or as organic compound, in the setting of nutrients and water in the ground in order to improve the practical agriculturists, to reduce costs and the "importation" of chemical fertilizers. The methodology involves bibliographical study on the composting technique, consisting of developing all the stages that will be given clearer in the developing of the field works, for a future deployment of a unit of Composting, to apply for agriculture of the related city.

Esta dissertação tem como objetivo, a apresentação de uma proposta para os resíduos agroextrativistas a fim de encontrar um composto orgânico ideal para ser utilizado na agricultura do Município de Laranjal do Jari, no Estado do Amapá. A técnica em questão será a compostagem, gerando uma alternativa de utilização para os resíduos de natureza local, onde atualmente não vêm sendo aproveitados. Para se chegar ao composto ideal serão utilizados basicamente: caroços de açaí e cascas de castanha. Esses resíduos vêm sendo relegados através dos Serviços de Limpeza Pública, constituindo não só um problema estético ou ambiental, mas de desperdício de energia e materiais que poderiam ser utilizados na recuperação de áreas degradadas ou como composto orgânico, na fixação de nutrientes e água no solo a fim de melhorar as práticas agrícolas, reduzir custos e a importação de fertilizantes químicos. A metodologia envolve estudo bibliográfico sobre a técnica de compostagem, consistindo em desenvolver todas as etapas que se darão mais claras, no desenvolver dos trabalhos de campo, para uma futura implantação de uma Unidade de Compostagem, a ser aplicável para a agricultura do referido município. / This work has the objective, to present a proposal for the agriculture-extractive residues to find an organic compound ideal for use in agriculture of the Laranjal do Jari, in the state of Amapá. The technique in question will be composting, generating an alternative to use for the residues of local nature, where currently they do not come being used to advantage. To arrive itself at the ideal composition they be used basically: açaí seeds and chestnut rinds. These residues came being relegated through the Services Public Cleaning, constituting not only an aesthetic or environmental problem, but of wastefulness of energy and materials that could be used in the recovery of degraded areas or as organic compound, in the setting of nutrients and water in the ground in order to improve the practical agriculturists, to reduce costs and the "importation" of chemical fertilizers. The methodology involves bibliographical study on the composting technique, consisting of developing all the stages that will be given clearer in the developing of the field works, for a future deployment of a unit of Composting, to apply for agriculture of the related city.