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Trace elements in soils and vegetables in a periurban market garden in Yunnan Province (P.R. China): evaluation and experimentation / Eléments en trace dans les sols et les légumes dune zone maraîchère périurbaine de la Province du Yunnan (RP de Chine) : évaluation et expérimentationZu, Yanqun 19 September 2008 (has links)
This research was conducted in order to evaluate natural trace element (TE) contents and anthropogenic contamination in soils and vegetables in Chenggong County (Yunnan Province, China). In this way, trace element contents in soils have been analysed to assess TE contamination in soils and vegetables, and transfer of TE from soil to vegetables. Agricultural practises have been proposed to amend the quality of vegetables.
We identified three geomorphopedological units: lacustrine unit, transition unit and mountain unit.
In the mountain unit, soil texture is clay more often from the weathering of limestone and marlstone. Soil colour is red or reddish brown with acid reaction.
In the transition unit, soil texture is loamy clay. Soil colour is red-brown with acid reaction.
In the lacustrine unit, soil texture mainly is sandy developed from lacustrine-alluvial deposits. Soil colour is brown and is slightly acid.
Total TE contents in the topsoil are higher than usual and even Kunming Prefecture soil. TE contents indicate a high contaminated level when considered globally. Pb, Cd and Zn present however individually low contaminated levels, and Cu presents a medium contaminated level. TE contents decrease from northeast to southwest, which is consistent with the elevation gradient. Significant differences of TE contents are observed according to distance from Chenggong town in the lacustrine unit and with distance from the mountain in the transition unit. TE accumulation is usually observed along roads. TE contents in subsoil are related to soil colour, texture, parent materials and mottles. Accumulation of Pb and Zn in topsoil and of Cu and Cd in subsoil are observed.
The highest contents are observed for Pb in cauliflower, Cd in lettuce and Chinese cabbage, and Cu and Zn in pea. The order of TE accumulation in plants varies according to the plant species and organ. According to relations between TE contents in Chinese cabbage and extraction sequential fractions of TE in soils, different soil fractions are suggested as soil assessment indicators.
Lime and pig manure have been applied to modify the soil pH and to decrease the mobility of TE in situ. With increasing in lime rate and pH, contents of acetic-acid extractable TE fractions in soil decrease. Enrichment coefficients related to TE availability (AEC) of Pb and Cu are stable and are not changed by lime or pig manure. AEC of Cd and Zn which are high in low pH, decrease with increased pH and application rates of lime and pig manure.
When application rates of lime and pig manure increase, TE contents in Chinese cabbage decrease and biomass of Chinese cabbage increases. Application rates of lime and pig manure are recommended, but their quality should also be taken into account.
/
Cette recherche a pour objet l'étude de la teneur naturelle en éléments traces métalliques (ET) et de la contamination anthropique des sols et des productions légumières dans le Comté de Chenggong (Province du Yunnan, RP de Chine).
Pour cela, la variabilité des teneurs en fonction des conditions géomorphopédologiques a été analysée, ainsi que les transferts des ET du sol vers les végétaux. Cette approche a permis ensuite d'aborder l'évaluation de la qualité des sols et des légumes, puis de proposer des pratiques agricoles alternatives dans le but d'améliorer la qualité des légumes produits.
La zone d'étude a été divisée en 3 unités géomorphopédologiques:
unité de montagne où les sols brun rouge à rouge résultent notamment de l'altération de calcaires et de marnes. Une texture argileuse et une réaction acide dominent.
unité de piedmont (dite de transition) où les sols de couleur jaune clair à jaune rougeâtre résultent principalement de l'altération de grès et de shales. Une texture limono-argileuse en surface et argileuse en profondeur, ainsi quune réaction acide dominent.
unité lacustre, à proximité du Dianchi Lake, dont les sols de couleur brun foncé sont essentiellement développés à partir de sédiments lacustres. Une texture sableuse domine en surface, ainsi qu'une réaction faiblement acide à neutre.
Les teneurs en ET rencontrées en surface des sols de la zone d'étude sont plus élevées que les teneurs moyennes observées dans les sols du monde ou même de la préfecture de Kunming. Evaluées séparément pour chaque ET, les teneurs rencontrées correspondent à des niveaux de contamination jugés faibles pour Pb, Cd et Zn, moyen pour Cu. Considérées simultanément, ces teneurs permettent de déterminer un indice de contamination global correspondant à un niveau de contamination élevé. Les teneurs en ET décroissent globalement du nord-est vers le sud-ouest, suivant le gradient d'altitude. Ces teneurs varient également de façon significative en fonction de l'éloignement de la montagne dans l'unité de transition et de l'éloignement de l'agglomération de Chenggong dans l'unité lacustre . Une accumulation en ET est souvent observée le long des routes. Dans le sous-sol, les teneurs en ET sont liées à la couleur, à la texture, au matériau parental, et aux marques d'altération. Les teneurs sont plus élevées en surface pour Pb et Zn, et en profondeur pour Cu et Cd.
Les teneurs les plus élevées pour Pb sont observées dans le chou-fleur, pour Cd dans la laitue et le chou chinois, pour Cu et Zn dans le pois.L'ordre d'accumulation des ET dans la plante dépend de l'espèce et de l'organe considérés. En fonction des corrélations observées entre les teneurs du chou chinois et les résultats obtenus avec différentes modalités d'extraction des ET du sol, des indicateurs d'évaluation de la qualité du sol ont été proposés.
Un amendement carbonaté et du fumier de porc ont été épandus afin de réduire in situ la mobilité des ET. L'augmentation de l'apport d'amendement carbonaté permet d'augmenter le pH du sol et de diminuer la fraction extraite avec l'acide acétique dilué (AA) pour chaque élément. Les AEC, rapports teneur dans la plante : teneur dans le sol extractible à lAA, sont stables pour Pb et Cu et ne sont modifiés par aucun des 2 apports. Cependant, les AEC de Zn et de Cu, élevés quand le pH du sol est acide, diminuent si le pH devient plus alcalin, ainsi qu'avec les apports d'amendement carbonaté et de fumier de porc.
Quand les apports d'amendement carbonaté et de fumier de porc augmentent, les teneurs en ET du chou chinois diminuent et sa biomasse augmente. Un épandage d'amendement carbonaté est donc recommandé. Cependant la plus grande attention doit être portée à la qualité des fumiers de porcs dont les teneurs en Zn et Cu ne sont pas négligeables.
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Use Of Granulated Blast Furnace Slag, Steel Slag And Fly Ash In Cement-bentonite Slurry Wall ConstructionTalefirouz, Davood 01 January 2013 (has links) (PDF)
Slurry walls have been widely used for more than 25 years to control the migration of contaminants in the subsurface. In the USA, vertical barriers are mostly constructed of soil-bentonite using the slurry trench method of construction. In this method, sodium bentonite is mixed with water to form a viscous slurry that is pumped into a trench during excavation to maintain the trench stability. The stable trench is then backfilled with a mixture of soil and slurry having a consistency of high slump concrete. These barriers have been designed primarily for low permeability, generally less than 10&minus / 9 m/s. Some investigations have pointed toward improved performance using admixtures that would provide low permeability. In this study, Soma thermal power plant fly ash, granulated blast furnace slag, lime, and steel slag are used as admixture to improve the performance of slurry walls. Permeability, compressive strength, slump, compressibility properties of the mixtures were found and checked for the minimum requirements. According to the findings of this study, granulated blast furnace slag (GGBS), fly ash and steel slag can be used at certain percentages and curing periods as additive in cement-bentonite barrier wall construction. Permeability of specimens having fly ash decreases by increasing fly ash content. Mixtures having 50 % of GGBS type I with 5 % of lime and 9% bentonite content gave acceptable results in 28 days of curing time. Specimens including 50 % of GGBS type II with 5 % of lime and 9% bentonite content gave the higher permeability value in 28 days of curing time with respect to GGBS type I. In addition, most of the mixtures prepared by steel slag gave the acceptable permeability values in 28 days of curing period. Unconfined compressive strength of all mixtures increase by increasing curing time. Cc, Cr, Cv, kcon values were found from consolidation test results. Permeability values found from consolidation tests are 10 times to 100 times higher than flexible wall k results for the same effective stress of 150 kPa. Generally, mv values are decreasing with increasing curing time. As mv decreases, D increases.
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Stabilization Of Expansive Soils By Cayirhan Fly Ash And DesulphogypsumCetiner, Sertan Isik 01 January 2004 (has links) (PDF)
Expansive soils are one of the most serious problems which the foundation
engineer faces. Several attempts are being made to control the swell-shrink
behavior of these soils. One of the most effective and economical methods is to use
chemical additives. Fly ash and desulphogypsum, both of which are by-products of
coal burning thermal power plants, are accumulating in large quantities all over the
world and pose serious environmental problems. In this study, the expansive soil
was stabilized using the fly ash and desulphogypsum obtained from Ç / ayirhan
Thermal Power Plant. Fly ash and desulphogypsum were added to the expansive
soil from 0 to 30 percent. Lime was used to see how efficient fly ash and
desulphogypsum on expansive soil stabilization were, and was added to the
expansive soil from 0 to 8 percent. The properties obtained were chemical
composition, grain size distribution, consistency limits, swelling percentage, and
rate of swell. Fly ash, desulphogypsum, and lime added samples were cured for 7
days and 28 days, after which they were subjected to free swell tests. Swelling
percentage decreased and rate of swell increased with increasing stabilizer
percentage. Curing resulted in further reduction in swelling percentage and further increase in rate of swell. 25 percent and 30 percent fly ash and desulphogypsum
additions reduced the swelling percentage to levels comparable to lime stabilization.
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Stabilization Of Expansive Soils By Using Aggregate Waste, Rock Powder And LimeYesilbas, Gulsah 01 May 2004 (has links) (PDF)
Expansive soils are a worldwide problem that poses several challenges for civil engineers. Such soils swell when given an access to water and shrink when they dry out. The most common and economical method for stabilizing these soils is using admixtures that prevent volume changes. In this study the effect of using rock powder and aggregate waste with lime in reducing the swelling potential is examined. The expansive soil used in this study is prepared in the laboratory by mixturing kaolinite and bentonite. Lime was added to the soil at 0 to 9 percent by weight. Aggregate waste and rock powder were added to the soil at 0 to 25 percent by weight. Grain size distribution, Atterberg limits and swell percent and rate of swell of the mixtures were determined. Specimens were cured for 7 and 28 days. This method of treatment caused a reduction in the swelling potential and the reduction was increased with increasing percent stabilizers.
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Estudo da incorpora??o da cal em composi??es bin?rias de solo-cimento para produ??o de tijolos maci?osG?is, Luciano Costa de 17 December 2012 (has links)
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Previous issue date: 2012-12-17 / The use of binders in the soil for the production of solid bricks is an old construction technique that has been used by several civilizations over time. At the same time, the need for environmental preservation and the tendency of scarcity of natural resources make the construction invest in researching new concepts, methods and materials for building systems for the sustainability of their economic activities. Thus arises the need to obtain building materials with low power consumption, capable of reducing the growing housing shortage of rural and urban population. Currently, research has been conducted on this topic to better understand the cementitious and pozzolanic reactions that occur in the formation of the microstructure of the soil-cement when added to other materials such as, for example, lime, and the relationship between microstructure and formed interfaces with the physical, mechanical and chemical analysis in compounds made from these ternary compositions. In this context, this study aimed to analyze the results of the influence of the incorporation of lime to the soil-cement to form a ternary mixture to produce soil-cement bricks and mortar without structural purposes. From the inclusion of contents of 6 %, 8 %, 10% and 12% lime to the soil, and soil-cement mixes in amounts of 2 %, 3 %, 4 % and 5 % were shaped-bodies of -cylindrical specimens to determine the optimum moisture content and maximum dry apparent specific weight. Then they were cured, and subjected to the tests of compressive strength, absorption and durability modified. Compositions obtained the best results in the tests performed on the bodies-of-proof cylindrical served as a parameter for molding of solid bricks, which underwent the same experimental methodology previously cited. The raw materials used, as well as compositions in which the bricks were molded solid, were characterized by physical and chemical tests, X-ray diffraction and scanning electron microscopy. The results obtained in the study indicate that the compositions studied, that showed the best results in terms of compressive strength, water absorption and durability ternary composition was soil, 10 % cement and 2 % lime / O uso de aglomerantes no solo para a produ??o de tijolos maci?os ? uma t?cnica construtiva antiga que tem sido utilizada por diversas civiliza??es ao longo do tempo. Ao mesmo tempo, a necessidade de preserva??o ambiental e a tend?ncia de escassez dos recursos naturais fazem com que a constru??o civil invista na pesquisa de novos conceitos, m?todos e materiais para os sistemas construtivos visando ? sustentabilidade econ?mica de suas atividades. Sendo assim, surge a necessidade de se obter materiais de constru??o com baixo consumo de energia, com capacidade de reduzir o crescente d?ficit habitacional da popula??o rural e urbana. Atualmente, pesquisas t?m sido realizadas sobre esse tema, visando compreender melhor as rea??es ciment?cias e pozol?nicas que ocorrem na forma??o da microestrutura do sistema solo-cimento quando adicionados outros materiais, como, por exemplo, a cal, e a rela??o existente entre a microestrutura formada e suas interfaces, com as propriedades f?sicas, mec?nicas e qu?micas verificadas nos compostos produzidos a partir dessas composi??es tern?rias. Nesse contexto, esse trabalho teve por objetivo analisar os resultados da influ?ncia da incorpora??o da cal ao solo-cimento para compor uma mistura tern?ria para produ??o de tijolos de solo-cimento e cal sem fins estruturais. A partir da inclus?o de teores de 6 %, 8 %, 10 % e 12 % de cal ao solo, e em misturas de solo-cimento nos valores de 2 %, 3 %, 4 % e 5 %, foram conformados corpos-de-prova cil?ndricos para determina??o da umidade ?tima e do peso especifico aparente seco m?ximo. Em seguida os mesmos foram curados, e submetidos aos ensaios de resist?ncia ? compress?o simples, absor??o e durabilidade modificada. As composi??es que obtiveram os melhores resultados nos ensaios realizados nos corpos-de-prova cil?ndricos serviram de par?metro para moldagem dos tijolos maci?os, que passaram pela mesma metodologia experimental anteriormente citada. As mat?rias-primas utilizadas, bem como as composi??es em que foram moldados os tijolos maci?os, foram caracterizadas atrav?s de ensaios f?sicos e qu?micos, difra??o de raios X e microscopia eletr?nica de varredura. Os resultados obtidos na pesquisa indicam que das composi??es estudadas, a que apresentou melhores resultados em termos de resist?ncia ? compress?o simples, absor??o de ?gua e durabilidade foi ? composi??o tern?ria de solo, 10 % de cimento e 2 % de cal
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Desenvolvimento de argamassa para restaura??o utilizando res?duo do polimento do porcelanatoBreitenbach, Silvia Becher 22 July 2013 (has links)
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Previous issue date: 2013-07-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The coatings mortars are essential elements of building structures because they execute an important role in protecting walls and are particularly exposed to aggressive action responsible for its degradation over time. The importance of wall coverings has been the subject of discussion and analysis in the conservation and rehabilitation of old buildings. Are sometimes removed and replaced with inappropriate solutions of constructive point of view or architecture. The most commonly used coatings on walls of old buildings is based on traditional hydraulic lime mortars. The present study aims at the formulation of new lime- based mortars and aerial fine aggregate, in order to contribute to a better field of conservation and restoration mortar coating of old buildings. Residue was used for polishing porcelain as fine aggregate, replacing the aggregate (sand), in percentages 05-30% by mass. We conducted a thorough evaluation of the mortar properties in fresh and hardened state by comparing the performance of the same with a reference mortar. The residue used was characterized as the density, bulk density, and particle size laser, scanning electron microscopy, X-ray diffraction and X-ray fluorescence. Formulations were produced 7, 6 with residue and one commonly used formulation, which served as a reference. In the formulations of lime mortars air (hydrated lime powder CH-I) has been adopted a stroke volume (1:3) with constant binder, was varied and the water / binder and aggregate and waste. For evaluation of mortars fresh, proceeded to consistency analysis, specific gravity, water retention and air content embedded. In the hardened state assays were performed in specific gravity, water retention, modulus of elasticity, tensile strength in bending, compressive strength, water absorption by capillary action, adhesion, tensile strength, resistance to shrinkage and salts by of crystallization trials with resources chloride solution, nitrate and sulfate all sodium in prismatic at 90 days of age, in addition to the micro structural analysis of mortars. Based on the results we can see that the mortar formulated with 10% content of waste and the reference free retraction feature more stable closer to neutrality. The composition of 10% was obtained better performance against the action of the salt crystallization. The mortar with 15% residue obtained better density, lower air content embedded and high capacity for water retention developing good workability. The replacement of 20% of waste generates a satisfactory utilization of resistance to compression, flexion and traction grip the base. And, finally, it can be seen that the mortar with 10, 15 and 20% residual show, in principle, good suitability as coatings, thus enabling a final result consistent with durability, workability and aesthetics developing therefore a material with better performance to repair or replace existing mortars in old buildings / Os revestimentos argamassados s?o elementos fundamentais em alvenaria estruturada, pois desempenham um papel importante na prote??o de alvenarias e encontram-se particularmente expostos a a??es agressivas respons?veis pela sua degrada??o ao longo do tempo. A import?ncia dos revestimentos de parede vem sendo alvo de discuss?o e an?lise no ?mbito da conserva??o e reabilita??o de pr?dios antigos. Por vezes, s?o removidos e substitu?dos por solu??es inadequadas, do ponto de vista construtivo ou arquitet?nico. Os revestimentos mais utilizados em paredes de edif?cios antigos baseiam-se em argamassas tradicionais de cal a?rea (cal hidratada em p? CH-I). O presente estudo tem como objetivo a formula??o de novas argamassas ? base de cal a?rea e agregado fino, com vistas a contribuir para o melhor dom?nio da conserva??o e restauro de argamassa de revestimento de edif?cios antigos. Foi utilizado res?duo do polimento de porcelanato como agregado fino, em substitui??o ao agregado mi?do (areia), em porcentagens de 05 a 30% em massa. Foi feita uma completa avalia??o das propriedades das argamassas no estado fresco e no estado endurecido comparando o desempenho das mesmas com uma argamassa de refer?ncia. O res?duo utilizado foi caracterizado quanto ? massa espec?fica, massa unit?ria, granulometria a laser, microscopia eletr?nica de varredura, difratometria de raios-X e fluoresc?ncia de raios-X. Foram produzidas 7 formula??es, sendo 6 com res?duo e 1 formula??o comumente usada, que serviu de refer?ncia. Nas formula??es das argamassas de cal a?rea adotou-se um tra?o volum?trico (1:3), com o ligante constante, e se fez variar a rela??o ?gua/aglomerante, bem como agregado mi?do e res?duo. Para avalia??o das argamassas no estado fresco, procedeu-se a an?lise da consist?ncia, densidade de massa aparente, reten??o de ?gua e teor de ar incorporado. J? no estado endurecido foram realizados os ensaios de densidade de massa aparente, reten??o de ?gua, m?dulo de elasticidade, resist?ncia ? tra??o na flex?o, resist?ncia ? compress?o, absor??o de ?gua por capilaridade, ader?ncia ? tra??o, retra??o e resist?ncia a sais, por meio de ensaios de cristaliza??o com recursos de solu??o de cloreto, nitrato e sulfato todos de s?dio, em corpos de prova prism?ticos aos 90 dias de idade, al?m das an?lises micro estruturais das argamassas. Com base nos resultados ? poss?vel verificar que a argamassa com teor de 10% de res?duo e a de refer?ncia apresentam retra??o livre mais est?vel, mais pr?xima da neutralidade. A composi??o de 10% apresenta melhor comportamento face ? a??o da cristaliza??o de sais. A argamassa formulada com 15% de res?duo obteve melhor densidade aparente no estado fresco, menor teor de ar incorporado e elevada capacidade de reten??o de ?gua desenvolvendo boa trabalhabilidade. A substitui??o de 20% de res?duo gera um aproveitamento satisfat?rio quanto ? resist?ncia ? compress?o, tra??o na flex?o e maior ader?ncia ? base. Portanto, podemos verificar que as argamassas com 10, 15 e 20% de res?duo evidenciam, a princ?pio, boa adequa??o como revestimento, possibilitando assim um resultado final compat?vel com a durabilidade, trabalhabilidade e ader?ncia desenvolvendo um material com melhor desempenho para reparar ou substituir argamassas existentes em edif?cios antigos
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Utilização do politereftalato de etileno (PET) em misturas asfálticas.SILVA, José de Arimatéia Almeida e. 05 June 2018 (has links)
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Previous issue date: 2015-06-26 / Capes / A adição do resíduo de Politereftalato de Etileno (PET) em Cimentos Asfálticos de Petróleo (CAP), triturados em partículas cujo diâmetro está entre 0,6 e 0,074 mm, pode ser uma alternativa técnica viável para melhorar as propriedades mecânicas e reológicas das misturas asfálticas. Esta adição tem como finalidade proporcionar uma menor susceptibilidade das misturas asfálticas a fadiga e, conseqüentemente
aumentar a vida útil de revestimentos asfálticos em regiões com clima tropical e a temperaturas elevadas. Este trabalho tem como objetivo principal a incorporação de um aditivo no Cimento Asfáltico de Petróleo. A adição de PET foi realizada em proporções de 4%, 5% e 6% relativas ao peso do teor de CAP ótimo e mensuradas as propriedades volumétricas e mecânicas. Além disso foram realizados análises físicas e reológicas do CAP puro e modificado. De acordo com os resultados obtidos nesta pesquisa pode -se inferir que o PET micronizado pós consumo corresponde a um polímero melhorador das propriedades reológicas do CAP 50/70, em termos de rigidez, proporcionado a mistura asfáltica um incremento no comportamento mecânico a luz dos ensaios de Resistência à Tração por Compressão Diametral, Módulo de Resiliência, Resistência por Umidade Induzida, Flow Number e Ruptura por Fadiga. É possível aceitar
que “o resíduo do PET micronizado, no teor de 5% pode ser utilizado como agente modificador do CAP e, que o mesmo e capaz de promover ganhos nas Propriedades Mecânicas de Revestimentos Asfálticos. / The addition of polyethylene terephthalate (PET) waste in binder, crushed into particles whose diameter is between 0.074 and 0.6 mm, may be a viable alternative technique to improve the mechanical and rheological properties of asphalt mixtures . This addition is intended to provide a lower susceptibility of fatigue in asphalt mixtures and consequently improve the durability of asphalt mixtures in regions with tropical climate and high temperatures. This work has the objective the incorporation of an additive in
binder. It was add in proportions of 4% 5% and 6% relative to the weight of the optimum binder content and it was measured volumetric and mechanical properties of asphalt mixtures. Also performed were physical and rheological analysis of pure and modified binder. According to the results obtained in this study can be inferred that the micronized PET improve the performance of binder 50/70. The addition of PET provided an increase in the mechanical behavior in the Indirect Tensile Strength, Resilient Modulus,
Moisture susceptibility, Flow Number and Fatigue life. It is possible to accept that the use of 5% micronized PET waste may be used as modifying agent of binder, and that it improve mechanical properties of asphalt mixtures.
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Influência da adição de resíduos industriais na durabilidade de blocos solo-cal.FIGUEIREDO, Suélen Silva. 26 June 2018 (has links)
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Previous issue date: 2015-08-26 / Capes / As indústrias do beneficiamento de rochas ornamentais, da cerâmica vermelha e do caulim, geram grande volume de resíduos, que geralmente são dispostos no meio ambiente de forma inadequada, causando graves impactos ambientais. A reinserção de resíduos industriais na cadeia produtiva como matéria prima, no desenvolvimento de insumos da construção, vem sendo uma alternativa avaliada por diversos pesquisadores. Os resultados de pesquisas apontam que estes resíduos, quando beneficiados podem apresentar propriedades aglomerantes que viabilizam sua incorporação em substituição parcial à cal na confecção de blocos solo-cal. Dentre os materiais alternativos, o bloco solo-cal possui vantagens como simplicidade de produção, resistência à compressão semelhante aos blocos convencionais, não passam pelo processo de cozimento e possibilitam a incorporação de resíduos com potencial aglomerante à sua matriz. Porém para assegurar confiabilidade nas aplicações desses novos materiais, é fundamental a avaliação da durabilidade. Este trabalho de pesquisa teve como objetivo avaliar a durabilidade de blocos solo-cal incorporados com resíduos industriais provenientes do beneficiamento de rochas ornamentais, da fabricação da cerâmica vermelha e do beneficiamento do caulim. Confeccionaram-se blocos no traço 1:10 em proporção de cal:solo, e utilizando os resíduos em substituição parcial a cal, nas proporções de 15%, 30% e 50% para períodos de cura de 28, 60 e 90 dias. Os materiais utilizados foram submetidos aos ensaios de caracterização físico-mineralógica, tais como:granulometria por peneiramento e difração a laser, análise química, análise
termodiferencial, análise termogravimétrica, e difração de raios X. O estudo da
durabilidade foi realizado utilizando-se o envelhecimento natural, o envelhecimento acelerado pela técnica de molhagem e secagem , simulação da chuva dirigida e
resistência ao ataque de sulfatos, tomando-se como parâmetro de degradação a
resistência à compressão simples dos blocos. Os resultados evidenciaram que a
incorporação de 15% de resíduo cerâmico e de caulim ao bloco solo-cal não
compromete sua durabilidade. / The industries of beneficiation of ornamental rocks, red ceramic and kaolin,
generate large volume of waste, which are mostly discharged into the environment
irregularly, thus causing serious environmental impacts. The reintegration of
industrial waste in the productive chain, as raw material in the development for
building materials, are being an alternative evaluated by several researchers. Among
the alternative materials, soil-lime blocks has advantages such as simplicity of
production, compression resistance similar to conventional blocks, are not submitted
to the cooking process and enable the incorporation of waste with potential binder to
matrix. Research results indicate that these residues when finely ground may submit
caking properties that enable its incorporation in partial substitution of lime in soillime blocks manufacture. But to ensure reliability to alternative materials is essential
evaluating their durability. This research aimed to evaluate the durability of soil-lime
blocks incorporated with industrial waste arising from the processing of ornamental
rocks, manufacturing of red ceramic and kaolin. Specimens were made at the dash
1:10 in ratio of lime: soil, and using waste to partially replace lime in the proportions
15%, 30% and 50% for curing periods of 28, 60 and 90 days. The materials were
subjected to physical and mineralogical characterization tests, such as: granulometry
by sieving and laser diffraction, chemical analysis, thermo differential analysis,
thermo gravimetric analysis, and X-ray diffraction. The study of the durability was
performed using the natural aging, accelerated aging by the technique of wetting and
drying, driving rain simulation and resistance to attack sulfates , taking as parameter
degradation the unconfined compressive strength of the blocks. The results showed
that the incorporation of 15% ceramic waste and kaolin in soil -lime block does not
compromise its durability.
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Análise comparativa da composição química de aço e escória e rendimento metálico de um FEA entre parâmetros de carregamento e injeções distintosVieira, Deisi January 2017 (has links)
Aliar alta produtividade ao menor custo de processo é o principal desafio econômico de uma Aciaria Elétrica. Para isso, mudanças no processo almejando práticas que resultam em uma maior eficiência do FEA, com um menor custo envolvido, ocorrem constantemente. Este trabalho avalia um processo de FEA, com capacidade de 62 toneladas de aço, operando com carregamento de sucata metálica e ferro-gusa. Dois grupos de corridas de aço, pertencentes à dois cenários distintos, foram estudadas. Os cenários foram denominados Cenário I e Cenário II, sendo que, no segundo cenário ocorreram mudanças nas práticas de injeções de carbono e oxigênio, nas práticas de adição de cales no carregamento e mudanças na quantidade de Sucata Shredder no FEA. O objetivo deste trabalho foi analisar como essas mudanças influenciaram no processo. A composição química de aço e escória de dois padrões de carga (C e E) foi comparada entre os cenários. Verificou-se que a massa de escória diminuiu para os dois padrões de carga. Porém, a basicidade do padrão C foi reduzida de 2,5 para 2,1, enquanto para o padrão E manteve-se em 2,2 para os dois cenários. O MgO de saturação foi avaliado através de diagramas de saturação isotérmicos (ISD), e a maior parte das corridas do Cenário II ficaram acima da linha de saturação da escória. Houve uma redução de 30% do oxigênio injetado para os dois padrões e seus teores de fósforo no aço aumentaram significativamente. No entanto, apenas o padrão C teve uma variação nos teores de carbono no aço. A energia elétrica consumida mostrou-se dependente dos teores de FeO e MgO da escória. O padrão E apresentou um aumento significativo de 10 kWh/t. O rendimento metálico dos padrões C e E aumentou 3,59% e 2,22%, respectivamente. No Cenário II, o aumento da sucata Shredder no carregamento foi duas vezes maior. O Cenário II apresentou uma redução dos teores de cobre no aço para os dois padrões. As quantidades médias de injeção de carbono não tiveram variação significativa, por outro lado, através dos gráficos de distribuição, notou-se uma maior estabilidade nos valores de injeção. Para o padrão E observou-se uma quantidade mínima de ferro na escória para a razão global C/O de 0,75. Uma análise da razão das injeções de carbono e oxigênio durante o refino foi feita. Observou-se uma maior estabilidade das injeções ao longo do tempo de refino para o Cenário II em ambos os padrões. / Combine high productivity and lower costs is the main economical challenge of a steelmaking melt shop. Therefore, changes in the process aiming practices that result in higher efficiency of the EAF, with lower costs, occur frequently. This work evaluates an EAF process, with capacity of 62t of steel, operating with metal scrap and pig iron load. Two groups of steel heats that represents two distinct scenarios were studied. The scenarios were called Scenario I and Scenario II. In the Scenario II carbon and oxygen injection practices, limes loading practice and Shredder scrap loading amount were modified. The aim of the present work is analyze how these changes affected process parameters. The steel and slag chemical composition of two loading patterns (C and E) was compared on the scenarios. It was found that the slag mass reduces for both loading patterns. However, the basicity of the pattern C was reduced from 2.5 to 2.1 while the pattern E was maintained on 2.2 for both scenarios. The MgO saturation content of the slag is evaluated through Isothermal Solubility Diagrams. Most of the heats of the Scenario II MgO content are higher than the minimal saturation content. There was a reduction of 30% of the injected oxygen for both loading patterns and their P content increased significantly. Meanwhile, only the pattern C shows a variation on carbon content in the steel. The electric power consumption showed proportional relation to FeO and MgO content of the slag and the pattern E showed a significant increase of 10 kWh/t. The metallic yield of the patterns C and E increased 3.59 and 2.22, respectively. The scenario II showed a reduction of the Cu content in both patterns. The carbon injection amount means did not vary significantly, but, through distribution graphs, was noted a higher stability in the injection amount. For the E pattern, a minimum amount of iron in the slag was observed for the overall C/O ratio of 0,75. An analysis of the ratio of the carbon and oxygen injection during the refining period was done. It was observed a higher stability of the injections along the refining period for the Scenario II on both patterns.
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Desempenho de misturas de distintos materiais com cinza volante e cal submetidas a condições climáticas severasGodoy, Vinícius Batista January 2018 (has links)
A aplicação prática de resíduos industriais, como cinza volante proveniente da queima de carvão, em bases e sub-bases de rodovias, é de grande interesse para engenheiros geotécnicos, uma vez que reduz o consumo de recursos naturais e oferece um destino a esses resíduos. Nesse sentido, esta dissertação de mestrado avalia o desempenho de misturas cinza volante-cal submetidas a condições climáticas extremas. Foram analisadas as propriedades resistência, rigidez e durabilidade de misturas de cinza volante (25%) com areia de Osório, comparando-se ciclos de molhagem-secagem com ciclos de congelamento-degelo. Para isso variou-se: o teor de cal hidratada (3%, 5%, 7%), o grau de compactação (14,0 kN/m³, 15,0 kN/m³, 16,0 kN/m³), a adição de 0,5% de cloreto de sódio (NaCl) como catalisador e a adição de 0,5% de fibras de polipropileno. Foi estudada a influência da temperatura (23°C e 40°C) em um período de 7 dias de cura, chegando-se à conclusão que o aumento de temperatura proporciona elevados ganhos de durabilidade por congelamento e degelo, resistência e rigidez, assim como a adição de sal e fibras de polipropileno Visando ampliar esta pesquisa foi proposta a troca da matriz da mistura (areia de Osório) por fresado (RAP) e a cal hidratada pela cal de carbureto. Para esse novo tipo de mistura, também foi realizado ensaios triaxiais para análise do comportamento tensão-deformação em relação a adição de 0,5% de NaCl, onde percebeu-se um aumento de 3,4° no ângulo de atrito e de 42,8 kPa no intercepto coesivo. As misturas de RAP e cal de carbureto obtiveram melhores resultados de resistência por compressão e durabilidade do que as misturas com areia de Osório e cal dolomítica, para a mesma temperatura de cura. Posteriormente constatou-se que a perda de massa acumulada após os referidos tipos de ciclos é controlada pelo índice porosidade (η)/teor volumétrico de cal (Liv), para ambas as misturas. Além disso, percebeu-se que menores perdas de massa acumulada foram obtidas para os ciclos de molhagem e secagem comparados aos ciclos de congelamento e degelo, tanto para as misturas com areia quanto para as misturas com RAP. / The practical application of industrial residues, such as coal fly ash, on bases and sub-bases of highways, is of great interest to geotechnical engineers, since it reduces the consumption of natural resources and gives a destination to these residues. In this sense, this master's thesis evaluates the performance of coal fly ash-lime mixtures under extreme climatic conditions. Was analysed the impact of the hydrated lime content (3%, 5%, 7%), the degree of compaction (14.0 kN/m³, 15.0 kN/m³, 16.0 kN/m³), the addition of 0.5% sodium chloride (NaCl) as a catalyst and the addition of 0.5% polypropylene fibers, on strength, stiffness and durability (comparing freezing-thawing to wetting-drying cycles), in fly ash mixtures (25%) with Osório sand. The influence of temperature (23 °C and 40 °C) in a period of 7 days of cure was also studied, this increase in temperature has been shown to provide high durability (for freezeing-thawing cycles), strength and stiffness gains, as well as addition of salt and polypropylene fibers. In order to extend this research, it was propose the exchange of the matrix’s mixture (Osório sand) by reclaimed asphalt paving (RAP) and lime hydrated by carbide lime For this new type of mixture, triaxial tests are also performed to analyze the stress-strain behavior in relation to the addition of 0.5% NaCl, where a 3.4° increase in the friction angle was observed, and 42.8 kPa in the cohesive intercept. The mixtures of RAP and carbide lime obtained better strength and durability results than mixtures with Osório sand and dolomitic lime, for the same cure temperature. Subsequently, It was verified that the accumulated loss of after these kinds of cycles is controlled by the index of porosity (η) / volumetric content of lime (Liv), for both mixtures. Besides that, lower losses of accumulated mass was observed for the wetting and drying cycles, compared to the freezing and thawing cycles.
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