Dissertations / Theses on the topic 'Drainage rate'

Although mining is essential to life in our modern society, it generates huge amounts of waste that can lead to acid mine drainage (AMD). Most of these mine wastes occur as large piles that are open to the atmosphere so that air and water vapor can circulate through them. This study addresses the reactions and transformations of the minerals that occur in humid air in the pore spaces in the waste piles. The rate of pyrite oxidation in moist air was determined by measuring over time the change in pressure between a sealed chamber containing pyrite plus oxygen and a control. The experiments carried out at 25?C, 96.8% fixed relative humidity, and oxygen partial pressures of 0.21, 0.61, and 1.00 showed that the rate of oxygen consumption is a function of oxygen partial pressure and time. The rates of oxygen consumption fit the expression (dn/dt=(3.31x10^-7)(P^0.5)(t^-0.5) It appears that the rate slows with time because a thin layer of ferrous sulfate + sulfuric acid solution grows on pyrite and retards oxygen transport to the pyrite surface. The transformation of efflorescent sulfate minerals (the reaction products of iron sulfide oxidation) from a pyrrhotite-rich massive sulfide is explained using a systematic analysis of their stoichiometry and thermodynamics. Their stabilities are controlled by oxygen partial pressure, relative humidity, and activity of sulfuric acid and can be visualized using log activity of oxygen-log activity of water and log acitvity of sulfuric acid-log activity of water diagrams developed during this study. Samples from the field site were analyzed in the laboratory to determine mineralogy, equilibrium relative humidity, chemical composition, and acid generation potential. Dissolution experiments showed that fibroferrite-rich samples had the highest acid producing potential, followed by copiapite-rich samples and then halotrichite-rich samples. The most abundant metals in solutions produced by dissolving the salts were magnesium, aluminum, zinc, copper, calcium, and lead. The molar concentrations of the metals varied with mineralogy. However, all of these minerals release metals and acid when they dissolve and therefore represent a significant environmental threat.
Ph. D.

The cone penetration test (CPT), together with its recent variation (CPTU), has become the most widely used in-situ testing technique for soil profiling and geotechnical characterization. The knowledge gained over the last decades on the interpretation procedures in sands and clays is certainly wide, whilst very few contributions can be found as regards the analysis of CPT(u) data in intermediate soils. Indeed, it is widely accepted that at the standard rate of penetration (v = 20 mm/s), drained penetration occurs in sands while undrained penetration occurs in clays. However, a problem arise when the available interpretation approaches are applied to cone measurements in silts, sandy silts, silty or clayey sands, since such intermediate geomaterials are often characterized by permeability values within the range in which partial drainage is very likely to occur. Hence, the application of the available and well-established interpretation procedures, developed for ‘standard’ clays and sands, may result in invalid estimates of soil parameters. This study aims at providing a better understanding on the interpretation of CPTU data in natural sand and silt mixtures, by taking into account two main aspects, as specified below: 1)Investigating the effect of penetration rate on piezocone measurements, with the aim of identifying drainage conditions when cone penetration is performed at a standard rate. This part of the thesis has been carried out with reference to a specific CPTU database recently collected in a liquefaction-prone area (Emilia-Romagna Region, Italy). 2)Providing a better insight into the interpretation of piezocone tests in the widely studied silty sediments of the Venetian lagoon (Italy). Research has focused on the calibration and verification of some site-specific correlations, with special reference to the estimate of compressibility parameters for the assessment of long-term settlements of the Venetian coastal defences.

Os ensaios de palheta são frequentemente utilizados na estimativa da resistência não-drenada de depósitos de argilas moles devido à simplicidade do equipamento, rapidez de execução e baixo custo. A velocidade de deformação em ensaios de palheta de campo é, geralmente, de 6º/min. Contudo, os resultados destes ensaios são influenciados por vários fatores e, dentre eles, a velocidade de rotação pode ser considerada um dos mais importantes. Sob condições não-drenadas, os materiais argilosos apresentam ganho de resistência não-drenada com o aumento da velocidade de cisalhamento, resultante da viscosidade da água adsorvida nas partículas de solo. Como o ensaio de palheta tem sido cada vez mais utilizado para estimar a resistência não-drenada de outros solos de granulometria fina, como siltes, resíduos de mineração entre outros, é preciso ter cautela na interpretação dos resultados nestes materiais, pois a utilização da velocidade padrão de campo pode levar à ocorrência de drenagem parcial durante o cisalhamento e, nestes casos, os solos apresentam resistência e rigidez maiores que sob condições não-drenadas. Desta forma, o objetivo deste trabalho consiste na avaliação da influência da velocidade de rotação do ensaio de palheta na resistência dos solos. Foram realizados ensaios de palheta, utilizando palhetas de 20,2, 25,5 e 40,0 mm de diâmetro e com relação altura-diâmetro igual a 2 a velocidades de rotação de 0,68 a 10800o/min, utilizando três misturas compostas por 85% caulim e 15% bentonita com 100, 130% e 160% de umidade (argilosas), uma mistura composta por caulim puro a 50% de umidade (silte) e uma mistura composta por 60% caulim e 40% areia com 40% de umidade (silte). A partir dos resultados dos ensaios de palheta, observou-se que a resistência não-drenada aumenta com a velocidade, sob condições não-drenadas, tanto para os solos argilosos quanto para os siltosos. A resistência não-drenada também é influenciada pelo diâmetro da palheta e pelo índice de vazios do solo, e consequentemente pelo seu teor de umidade. A resposta viscosa dos ensaios de palheta ao longo de toda a faixa não-drenada pode ser descrita por uma equação potencial (para valores de velocidade adimensional maiores que 10). Os solos siltosos, especialmente a argila misturada com areia, também apresentam aumento de resistência com o aumento da velocidade, sob condições não-drenadas, mais pronunciado que para os solos argilosos. Entretanto, a pequenas velocidades, uma parcela do excesso de poro pressão gerado durante a rotação da palheta foi dissipado, ocasionando efeitos de drenagem parcial durante o cisalhamento. O torque medido durante os ensaios é influenciado pelas dimensões da palheta. Porém, não foi verificada qualquer tendência de variação na resistência normalizada (T/Tref) decorrente das dimensões da palheta. A velocidade normalizada (V) considera diretamente, além da velocidade, a geometria da palheta e o coeficiente de adensamento do solo e reflete os efeitos de permeabilidade, rigidez e velocidade de cisalhamento, fatores que também controlam a viscosidade. Desta forma, os efeitos viscosos dos ensaios de palheta são representados com precisão no espaço normalizado. Além da avaliação dos efeitos de velocidade devido a viscosidade, a normalização dos resultados no espaço T/Tref versus V possibilita também a avaliação dos efeitos de drenagem parcial. Ou seja, dois fenômenos físicos distintos podem ser identificados e interpretados utilizando a mesma abordagem.
Vane tests are frequently used to estimate the undrained shear strength of soft clays deposits because of the equipment simplicity, speed and low costs. The strain rate used in vane shear tests is generally of 6o/min. However, vane tests results are influenced by many factors and rate of shear can be considered one of the most important. Under undrained conditions, undrained shear strength of clayey soils increases with shear velocity. This increase on undrained shear strength occurs due to viscous effects. Furthermore, this method has been used to estimate the undrained shear strength of other fine-grained materials such as silts, tailings, among others. Tests results interpretation must to be careful on these materials, because partial drainage can occur during shear tests conducted at the standard field shear rate. In this cases, soil strength and stiffness are higher than under undrained conditions. Thus, this research is aimed to evaluate the influence of the vane shear velocity in soils strength. Vane tests were conducted using vanes with 20.2, 25.5 and 40.0 mm in diameter and with aspect ratio of 2, at rotation rates from 0.68 to 1800o/min using three kaolin-bentonite mixtures composed by 85% kaolin and 15% bentonite with a water content of 100, 130 and 160% (clay), a mixture composed just by kaolin with a 50% water content (silt) and a mixture composed by 60% kaolin and 40% Osório sand with a 40% water content (silt). Tests results shows that clay and silt strength increases with shear rate, under undrained conditions. Undrained shear strength is also influenced by vane diameter and soil void ratio, and consequently by water content. Viscous response on vane tests throughout the undrained range of velocities can be described by a power law (for normalized velocity values further than 10). Silty soils, especially clay-sand mixtures under undrained conditions, exhibited a greater increase on strength than the increased observed for clayey soils. Neverthless, in some tests conducted at low shear velocities, part of pore pressure excess generated during vane rotation was dissipated, occasioning partial drainage effects during shear. The measured torque has been influenced by vane blade dimensions, but any variation on normalized resistance (T/Tref) wasn’t found as a result of vane dimensions. Normalized velocity considers directly peripheral velocity, vane geometry and soil coeficient of consolidation and reflects permeability, stifness and shear rate effects, factors that also control viscous effects. Thus, viscous effects in vane tests are accurately represented on normalized space. In addiction to rate effects due to viscosity evaluation, results normalization on T/Tref versus V space enable partial drainage effects assessment. It shows that the two distinct physical phenomena can be identified and interpreted using one single approach.

Industriella processer genererar utsläpp i form av bland annat luftföroreningar via processluften som i sin tur försämrar arbetsmiljön för industrins anställda. Enligt arbetsmiljölagen är arbetsgivaren skyldig att skydda de anställdas hälsa via en god arbetsmiljö och måste därmed rena processluften. Luftföroreningar består av aerosoler och definieras som en samling solida- eller vätskepartiklar svävandes i en gas. I rapporten behandlades aerosoler i form av oljepartiklar som genereras från källor som till exempel industriella processer som gjutning, slipning och värmebehandling. En sådan process kan släppa ut sex fat olja i luften per år och utan partikelavskiljning ökar processernas olje- och energiförbrukning markant. Avskiljning av aerosola oljepartiklar samlar upp oljan så den kan återanvändas samt minskar exponering som kan ge cancer och Hodgkins disease. Aerosol olja bör därför avskiljas ur processluften på grund av hälsoaspekter. Oljepartiklar avskiljs ur processluften via porösa material. Materialet ansluts till processen med skräddarsydda kanalsystem där processluften ventileras bort med undertryck via en fläktmotor. Oljepartiklar avskiljs i det porösa materialet och därmed ökar materialets mättnadsgrad, det vill säga att ackumulerad olja minskar materialets porositet. Materialets dräneringskapacitet ser till att mättnadsgraden begränsas och att oljan kan återanvändas. Ett effektivt material har lågt tryckfall och hög avskiljningsgrad. Dessa varierar med materialets struktur som fiberdiameter, fibermattans tjocklek samt antal veckningar av materialet. Ett material veckas för att öka materialarean och dess avskiljningsgrad men tryckfallet ökas också, därför är balans mellan tryckfall och avskiljningsgrad viktigt vid konstruktion av materialet. Ett icke veckat material benämns som platt material i rapporten. Utvärdering av tryckfall och avskiljningsgrad i ett veckat material är kostsamt både ekonomiskt och tidsmässigt medan platta material är effektivt ur båda aspekterna och därför är ett bättre alternativ med avseende på utvärdering. Syftet med examensarbetet var att öka kunskapen kring avskiljning av aerosola oljepartiklar i porösa material. Målet var att modellera veckade material utifrån experimentella tester av platta- och veckade material. I rapporten testades porösa material med olika fiberdiametrar experimentellt som både platta- och veckade material. Experimentella tester innebar att materialen testades praktiskt för tryckfall och avskiljningsgrader. Avskiljningsgrader mättes vid tre intervall av partikeldiametrar enligt 0,25–0,60 μm, 0,931–1,075 μm och 1,911–2,207 μm. Platta material testades vid fyra lufthastigheter för att illustrera ökningen av lufthastighet inom veckat material på grund av en ökande mättnadsgrad. Modellering innebar att en beräkningsmodell för veckat material byggdes och gavs indata utifrån experimentella tester av platta- och veckade material. Regressionsanalyser utfördes på mätresultaten från platta material och gav matematiska funktioner som användes i modellering av veckade material. Antal veckningar och mättnadsgrader modellerades utifrån experimentella resultat från veckade material. Mät- och modelleringsresultat varierade med materialets struktur. Det gav att tryckfall, avskiljnings- och mättnadsgrader ökade med minskande fiberdiameter och ökande mattjocklek för både platt- och veckat material. Modellering av tryckfall i veckat material avvek från praktiken med -30 % och -6 % för fiberdiameter 8 μm respektive 6 μm. Modellering av avskiljningsgrader i veckat material hade störst avvikelse på +30 % för partikeldiameter 0,25–0,60 μm i material med fiberdiameter 6 μm. Modelleringsresultat av veckat material varierade över materialets struktur och avvek därmed olika mycket från praktiken. Avvikelser i modellerat tryckfall och avskiljningsgrader i veckade material var på grund av luftens dynamiska tryck. Trycket på oljepartiklarna påverkade dräneringskapacitet och oljefördelning inom materialet. Oljefördelningen är därmed heterogen i praktiken vilket påverkar tryckfall och avskiljning i både praktik och modellering. Detta skapade osäkerheter och gjorde modelleringen mindre tillförlitlig. Därför kunde tryckfall och avskiljning inte modelleras i veckat material endast utifrån platta material. Förbättrad modellering kräver vidare studier angående oljefördelning inom materialet samt inverkan av luftflödets dynamiska tryck på dräneringskapacitet för att förbättra modellering av veckade material.
Industrial processes generate emissions in the form of, among other things, air pollution via the process air, which in turn degrades the working environment for industrial employees. According to the Work Environment Act, the employer is obliged to protect the health of the employees via a good work environment and must therefore clean the process air. Air pollutants consist of aerosols and are defined as a collection of solid or liquid particles floating in a gas. The report dealt with aerosols in the form of oil particles generated from sources such as industrial processes such as molding, grinding and heat treatment. Such a process can release six barrels of oil into the air per year and without particle separation, the processes' oil and energy consumption increases markedly. Separation of aerosol oil particles collects the oil so that it can be reused and reduces exposure that can cause cancer and Hodgkin's disease. Aerosol oil should therefore be separated from the process air due to health aspects. Oil particles are separated from the process air via porous materials. The material is connected to the process with tailor-made duct systems where the process air is ventilated away with negative pressure via a fan motor. Oil particles are separated in the porous material and thus the degree of saturation of the material increases, that is accumulated oil reduces the porosity of the material. The drainage capacity of the material ensures that the degree of saturation is limited and that the oil can be reused. An efficient material has a low pressure drop and a high separation rate. These vary with the structure of the material such as fiber diameter, the thickness of the fiber carpet and the number of folds of the material. A material is folded to increase the material area and its separation rate, but the pressure drop is also increased, therefore a balance between pressure drop and separation rate is important when designing the material. A non-pleated material is referred to as flat material in the report. Evaluation of pressure drop and separation rate in a pleated material is costly both financially and in terms of time, while flat materials are effective from both aspects and are therefore a better alternative regarding evaluation. The purpose of the thesis was to increase knowledge about the separation of aerosol oil particles in porous materials. The goal was to model pleated materials based on experimental tests of flat and pleated materials. In the report, porous materials with different fiber diameters were tested experimentally as both flat and pleated materials. Experimental tests meant that the materials were tested practically for pressure drops and separation rate. Separation rate was measured at three ranges of particle diameters according to 0.25–0.60 μm, 0.931–1.075 μm and 1.911–2.207 μm. Flat materials were tested at four air velocities to illustrate the increase in air velocity within pleated material due to an increasing degree of saturation. Modeling meant that a calculation model for pleated material was built and input data was given based on experimental tests of plate and pleated materials. Regression analyzes were performed on the measurement results from flat materials and gave mathematical functions that were used in modeling of pleated materials. The number of folds and degrees of saturation were modeled based on experimental results from pleated materials. Measurement and modeling results varied with the structure of the material. As a result, pressure drops, separation rate and degree of saturation increased with decreasing fiber diameter and increasing carpet thickness for both flat and pleated materials. Modeling of pressure drop in pleated material deviated from praxis by -30% and -6% for fiber diameters of 8 μm and 6μm, respectively. Modeling of separation rates in pleated material had the largest deviation of + 30% for particle diameter 0.25–0.60 μm in material with fiber diameter 6 μm. Modeling results of pleated material varied across the structure of the material and thus deviated differently from praxis. Deviations in modeled pressure drop and separation rates in pleated materials were due to the dynamic pressure of the air. The pressure on the oil particles affected drainage capacity and oil distribution within the material. The oil distribution is thus heterogeneous in praxis, which affects pressure drop and separation rate in both praxis and modeling. This created uncertainties and made modeling less reliable. Therefore, pressure drop and separation rate could not be modeled in pleated material based solely on flat materials. Improved modeling further requires studies regarding oil distribution within the material as well as the impact of the dynamic pressure of the air flow on drainage capacity to improve modeling of pleated materials.

O presente trabalho desenvolve uma proposta para a avaliação da redução da vazão de pico do hidrograma do método racional, no contexto de bacias hidrográficas topograficamente planas. Entendem-se como planas aquelas localidades, cujas declividades médias características e/ou projetadas são inferiores a 0,5%. Pretende-se também neste trabalho apresentar metodologias e práticas de projeto de drenagem usualmente adotadas em regiões de características topográficas semelhantes. No desenvolvimento do estudo, foram discutidas as bases teóricas do Método Racional e outros métodos de avaliação hidrológica que procuram levar em conta o amortecimento da vazão durante o seu escoamento sobre o leito das vias. Apresentam-se também as bases científicas para a criação de um modelo hidrodinâmico a ser usado no estudo para a determinação do fator de redução da vazão de pico do hidrograma racional. A capacidade de escoamento em vias urbanas é então discutida, de forma a se justificar as relações criadas como conclusão do trabalho. O resultado final apresentado é o estabelecimento de uma relação entre a variação do pico da vazão do Método Racional, com a capacidade de armazenamento ou amortecimento de cheias existente nessas vias. Relações estas que, para fins práticos, significam tanto o incremento positivo no período de retorno do projeto, quanto a redução da vazão para efeito de dimensionamento de galerias. Tais resultados são demonstrados de forma prática por meio do estudo de caso no município de Praia Grande, o litoral sul paulista.
This work presents a proposal for estimating the reduction of the Peak Flow Rate determined by the Rational Method, considering flat basins as a main characteristic. It is considered flat, all of those basins in which the average slope on the streets are smaller than 0,5 %. It is also intentions of this work discuss methods and practices adopted to flat areas as urban drainage solutions and best management practices. Within this work, we also present all the theoretical basis of the Rational Method, among others, that try to fuse the street storm water storage capacity whit the conveyance capacity of a usual street. It is also presented theoretical basis of hydrodynamic models to be used as the main tool to determine de peak flow reduction factor of the Rational Method Hydrogram. Conveyance capacity of a usual street is discussed, street storm water conveyance capacity is also discussed in order to justify the relations proposed as a conclusion of this work. As a result of this work it is established a relationship between the Peak flow rate determined by the Rational Method and the street storm water storage capacity. In addition, this peak reduction can be used as a positive increment on the Recurrence Interval or as flow rate reduction when designing the sewerage system, which means implementation costs reduction. An application to the city of Praia Grande, located the Sao Paulo State, is presented and used as a case of study.

Rare earth elements (REE) are known as the lanthanide series (La-Lu) plus yttrium (Y) and scandium (Sc). REE are essential materials for modern industries and especially for green technologies (wind turbines, batteries, lasers, catalysts, etc.). However, despite their high global demand, their supply is limited such that the EU has cataloged it as critical raw materials. In order to ensure the supply of REE in the future, the search for alternative sources of these elements worldwide has been promoted in recent years. Acid mine drainage (AMD) produced by the Fe-sulphide weathering can effectively leach Fe, Al, SO4, and REE from the host rock. This can lead to high concentrations of these liberated species in the affected waters. Thus, the REE concentrations in AMD can be between two and three orders of magnitude higher than natural waters, as such it can be considered as a complementary source of REE recovery. The increase of pH in AMD by mixing neutral waters results in the precipitation of iron oxy-hydroxysulfate (schwertmannite) from pH 3-3.5, and aluminum (basaluminite) from pH 4-4.5 in the river channels. This process may be accompanied by REE scavenging. Due to its acidity and high metal load, acid mine drainage presents a major environmental problem worldwide, therefore, different treatment systems have been developed to minimize its impact. Disperse Alkaline Substrate (DAS) passive remediation system neutralizes AMD by dissolving calcite, and allowing the sequential precipitation of schwertmannite and basaluminite in separated layers, where REE are preferably retained in the basaluminite-enriched waste. Despite this, there are still no studies describing the adsorption of REE on both basaluminite and schwertmannite in these environments. The REE scavenging mechanism is studied by adsorption on synthetic minerals of basaluminite and schwertmannite as a result of variation to the both the pH and sulfate concentration. A thermodynamic adsorption model is proposed based on experimental results in order to predict and explain the REE mobility in AMD mixtures with neutral waters and in a passive treatment system. Basaluminite and schwertmannite have a nanocrystalline character. Further, schwertmannite has been observed to transform into goethite on weekly timescales, resulting in sulfate release. However, there is a gap of knowledge about basaluminite stability at variable sulfate concentration and pH and its possible transformation to other more crystalline Al-minerals. In this study, basaluminite local order at different pH values and dissolved sulfate concentrations was characterized. Results demonstrate that basaluminite can transform to nanoboehmite in weeks under circumneutral pH. However, the presence of sulfate can inhibit this transformation. Separate adsorption experiments on both basaluminite and schwertmannite were performed with two different concentrations of SO4 while varying the pH (3-7). Results show that the adsorption is strongly dependent on pH, and to a lesser extent on sulfate concentration. Lanthanide and yttrium adsorption is most effective near pH 5 and higher, while that of scandium begins around pH 4. Due to the high concentrations of sulfate in acidic waters, the predominant aqueous REE species are sulfate complexes (MSO4+). Notably, Sc(OH)2+ represents a significant proportion of aqueous Sc. , A surface complexation model is proposed in which predominant aqueous species (Mz+) adsorb on the mineral surface, XOH, following the reaction: The adsorption of the lanthanides and yttrium occurs through the exchange of one and two protons from the basaluminite and schwertmannite surface, respectively, with the aqueous sulfate complexes. The sorbed species form monodentate surface complexes with the aluminum mineral and bidentate with the iron mineral. In the case of Sc, the aqueous species ScSO4+ and Sc(OH)2+ form bidentate surface complexes with both minerals. EXAFS analysis of the YSO4+ complex adsorbed on the basaluminite surface suggests the formation of a monodentate inner sphere complex, in agreement with the proposed thermodynamic model. Once the surface complexation model was validated, it was used to asses and predict the REE mobility in passive remediation systems and acidic water mixing zones with alkaline inputs from the field. The REE are preferentially retained in basaluminite-rich waste during passive remediation due to its sorption capacity between pH 5-6. In contrast, schwertmannite waste contains very little REE because the formation of this mineral occurs at pH lower than 4, which prevents REE adsorption. Further, Sc may be scavenged during schwertmannite precipitation as a result of this low pH The model correctly predicts the absence of REE in schwertmannite precipitates and the enrichment of the heavy and intermediate REE with respect to the light REE in basaluminite precipitates collected in the water mixing zones. However, there is a systematic overestimation of the fractionation of rare earths in basaluminite precipitate. This inaccuracy is mainly due to the fact that the mineral precipitation and adsorption are not synchronous process, while basaluminite precipitates from pH 4, REE adsorption occurs at higher pH values, between 5 and 7, when the water mixture reaches these values and a fraction of the particles have been dispersed.
Las tierras raras (en inglés rare earth elements, REE) son conocidas como el conjunto de la serie de los lantánidos (La-Lu), itrio (Y) y escandio(Sc). Las tierras raras son materiales indispensables para las industrias modernas y en especial para las tecnologías verdes (aerogeneradores, baterías, láseres, catalizadores, etc.). Sin embargo a pesar de su gran demanda mundial, su abastecimiento es limitado, por lo que han sido catalogadas por la UE como materias primas críticas (Critical Raw Materials). Con el objetivo de asegurar el abastecimiento de REE en el futuro, en los últimos años se ha promovido la búsqueda de fuentes alternativas de estos elementos en todo el mundo. El drenaje ácido de mina (en inglés acid mine drainage, AMD) producido por la meteorización de sulfuros de Fe, tiene un alto poder de lixiviación de las rocas, por lo que las aguas afectadas adquieren elevadas concentraciones en disolución de Fe, Al, SO4 y otros metales, como las REE. Así, las concentraciones de REE en AMD son entre dos y tres órdenes de magnitud superiores al resto de las aguas naturales y pueden suponer una fuente complementaria de recuperación de REE. El aumento de pH del AMD por mezcla con aguas neutras da lugar a la precipitación en los cauces de los ríos de oxy-hidroxisulfatos de hierro (schwertmannita), a partir de pH 3-3.5, y de aluminio (basaluminita), a partir de pH 4-4.5; acompañado de la eliminación de las tierras raras. Debido a su acidez y carga metálica, el drenaje ácido de mina presenta un problema medioambiental de primera magnitud, por lo que se han desarrollado diferentes sistemas de tratamiento para minimizar su impacto. El sistema de tratamiento pasivo Disperse Alkaline Substrate (DAS) produce la neutralización de las aguas ácidas por la disolución de la calcita presente en el sistema, permitiendo la precipitación secuencial, de schwertmannita y basaluminita. Las tierras raras quedan retenidas preferentemente en el residuo enriquecido en basaluminita. A pesar de ello, aún no existen estudios que describan la adsorción de tierras raras tanto en basaluminita como schwertmannita en estos ambientes. En esta tesis se estudia el mecanismo de retención de las tierras raras mediante adsorción en minerales sintéticos de basaluminita y schwertmannita, en función del pH y del contenido de sulfato disuelto. Con los resultados experimentales obtenidos, se propone un modelo termodinámico de adsorción para predecir y explicar la movilidad de las tierras raras observada en mezclas de AMD con aguas neutras y en un sistema de tratamiento pasivo. La basaluminita y la schwertmannita presentan un carácter nanocristalino. Es conocido que la schwertmannita se transforma en goethita en semanas, liberando sulfato. Sin embargo, nada se sabe de la basaluminita y su posible transformación a otros minerales de Al más cristalinos. De este modo, la caracterización del orden local de la basaluminita a diferentes valores de pH y sulfato se expone en primer lugar. Dependiendo del pH y el sulfato en disolución, la basaluminita se transforma en diferentes grados a nanoboehmita en semanas, pero tiende a estabilizarse con la presencia de sulfato en solución. Los experimentos de adsorción en basaluminita y schwertmannita con diferentes concentraciones de SO4 realizados para cada mineral y en rangos de 3-7 de pH han demostrado que la adsorción es fuertemente dependiente del pH, y en menor medida del sulfato. La adsorción de los lantánidos y del itrio es efectiva a pH 5, mientras que la del escandio comienza a pH 4. Debido a las altas concentraciones de sulfato en aguas ácidas, las especies acuosas predominantes de las tierras raras son los complejos con sulfato, MSO4+. Además del complejo sulfato, el Sc presenta importantes proporciones de Sc(OH)2+ en solución. En función de la dependencia del pH y de la importancia de la especiación acuosa, se propone un modelo de complejación superficial donde la especie acuosa predominante (Mz+) se adsorbe a la superficie libre el mineral, XOH, cumpliendo la siguiente reacción: La adsorción de los lantánidos y del itrio se produce a través del intercambio de uno o dos protones de la superficie de la basaluminita o de la schwertmannita, respectivamente, con los complejos sulfato acuoso, formando complejos superficiales monodentados con el mineral de aluminio y bidentados con el de hierro. En el caso del Sc, las especies acuosas ScSO4+ y Sc(OH)2+ forman complejos superficiales bidentados con ambos minerales. Complementando el modelo propuesto, el análisis de EXAFS del complejo YSO4+ adsorbido en la superficie basaluminita sugiere la formación de un complejo monodentado de esfera interna, coincidiendo con el modelo termodinámico propuesto. El modelo de complejación superficial, una vez validado, ha permitido evaluar y predecir la movilidad de REE en los sistemas de tratamiento pasivos y en zonas de mezcla de aguas ácidas con aportes alcalinos estudiados en el campo. La preferente retención de las tierras raras en la zona de la basaluminita precipitada en los sistemas de tratamiento pasivo ocurre por adsorción de las mismas a pH entre 5-6. La ausencia de tierras raras en la zona de schwertmannita se debe al bajo pH de su formación, inferior a 4, que impide la adsorción de las mismas. Sin embargo, debido a su menor pH de adsorción, una fracción de Sc puede quedar retenida en la schwertmannita. El modelo también predice correctamente la ausencia de REE en los precipitados de schwertmannita y el enriquecimiento de las tierras raras pesadas e intermedias respecto a las ligeras en los precipitados de basaluminita recogidos en el campo en las zonas de mezcla de aguas. Sin embargo, se ha observado una sistemática sobreestimación del fraccionamiento de las tierras raras en los precipitados de basaluminita. Este hecho se debe principalmente a que la precipitación del mineral no ocurre de forma síncrona con la adsorción, precipitando la basaluminita a partir de pH 4 y adsorbiendo tierras raras a pH más altos, entre 5 y 7, cuando las partículas sólidas han sido parcialmente dispersadas.

The goal in petrophyscial studies is very often to obtain representative capillary pressure curves in conjunction with Sw-RI relationships for log interpretation. The most frequently used techniques today are centrifugation, the porous plate and the mercury injection techniques.

Unlike the other methods, the strength of the porous plate technique is the possibility to establish both primary drainage, spontaneous imbibition, forced imbibition and secondary drainage without changing set up, conditions or method. In addition, the technique can be combined with resistivity measurements. The weakness is that the method requires a long experimental turnaround time.

Even though techniques like the membrane technique⁶, the continuous injection technique⁷, and the semi dynamic method⁸ have been introduced to the industry with a significant reduced turnaround time, the porous plate method is still believed to be the most representative method.

Its popularity in special core analysis has not dropped even after these new techniques were introduced to the industry.

The aim of this study is to experimentally test layered porous plate prototypes in capillary experiments for different capillary sequences, using all types of fluid pairs at different conditions, varying from ambient to extreme reservoir condition. The layered porous plate method is identical to the porous plate method, except for ceramic construction. In addition to this, the aim is to investigate if there is possible hysteresis between the two porous plate techniques, and investigates if this is related to reduced turnaround time. In other words, investigate how and when diaphragms influence drainage and imbibition rates in capillary experiments.

Another aim is to investigate if the layered porous plate technique can improve the continuous injection technique.

In this study a method of quantifying the influence of porous plates on effective rates at any stage and capillary sequence has been developed. The method is based on analysing transient capillary behaviour.

This dissertation includes theoretical and applied components that address the effect of coatings on rates of mineral reactions that occur in acid mine drainage (AMD) environments. The two major projects investigated how diffusion-limited transport of reactants through pore spaces in coatings on mineral grains affects the reaction rate of the underlying mineral. The first project considered the growth of gypsum coatings on the surface of dissolving limestone in anoxic limestone drains (ALD), which reduces the neutralization rate of the dissolving limestone and the subsequent effectiveness of this treatment. The second project investigated the conditions where iron oxyhydroxide coatings form on oxidizing pyrite and the potential strategies to prevent "runaway" AMD by reducing the rate of acid production to the point that the acid can be neutralized by the surrounding rocks. In both studies, experiments were conducted to measure reaction rates for the underlying minerals, as coatings grew thicker. These experimental data were fit to a diffusion model to estimate diffusion coefficients of reactants through pore spaces in coatings. These models are extrapolated to longer times to predict the behavior of the coated grains under field conditions. The experimental results indicate that management practices can be improved for ALDs and mine waste piles. For example, supersaturation with respect to gypsum, leading to coating formation, can be avoided by diluting the ALD feed solution or by replacing limestone with dolomite. AMD can be prevented if the rate of alkalinity addition to mine waste piles is faster than acid is produced by pyrite oxidation. The diffusion model developed in this study predicts when iron oxyhydroxide coatings will become thick enough that alkalinity from the surroundings is sufficient to neutralize acid produced by coated pyrite oxidation and additional alkalinity is no longer required.
Ph. D.

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The main purpose of this work was to identify and to estimate the rainfall derived infiltration and inflow (IADP) into the sewer in a small city and to do an analysis of their influence on this collection system. This work was composed by field measurements on the sewage flowrate output and volume arriving to the Sewage Pumping Plant Station, simultaneously to the collection and measurement of rainfall on the corresponding same urban watershed area of the Borborema, in São Paulo State. The existing methodologies were divided in the follow steps: choosing and characterization of the working field; data collection of the sewage volume and flowrate; collection of the rainfall data; choosing and characterization of the data collected; employment of existing models and methodologies useful to the present available data, in order to derive the underground water infiltration rate and the overflow occurring in the sewage colletion network. The volumetric and percentile IADP were quantified. The constant unitary rate (TUC) was also estimated, by several ways. The results allowed obtaining mathematical formulations to derive the IADP and TUC of the Borborema s sewage network. Such mathematical formulations are suitable to be applied in urban areas of cities of a similar to that of Borborema. It was estimated that the IADP can generate flowrates 2,5 times greater than the sewage flows in dry weather and infiltration rates in the sewage network similar to those adopted for system design. The work allowed to estimate how complex are the infiltration and inflow of stormwater in the sewer network. The methodologies applied were quite simple and may be easily applied in other cities.
O objetivo precípuo desta pesquisa foi identificar e estimar a infiltração e o afluxo devidos da precipitação (IADP) na rede de esgoto sanitário em município de pequeno porte e efetuar uma análise da sua influência no sistema de esgotamento sanitário. Este trabalho foi realizado através da medição em campo de vazão e volume de esgoto sanitário a montante da EEE Estação Elevatória de Esgoto, simultaneamente com a coleta e medição da chuva precipitada na correspondente área urbanizada da bacia hidrográfica da cidade de Borborema/SP. As metodologias empregadas foram divididas nas seguintes fases: escolha e caracterização do local da pesquisa; coleta de dados de vazão e volume dos efluentes de esgotos sanitários e coleta de dados de precipitação de chuva no local do estudo; seleção e caracterização dos dados coletados; aplicação das metodologias e modelagens existentes possíveis de aplicar em função dos dados disponíveis, para a obtenção da taxa de infiltração das águas subterrâneas e da sobrecarga na rede de esgoto sanitário. Quantificou-se o IADP volumétrica e percentualmente. Calculou-se também a taxa unitária constante (TUC), sob diferentes formatos. Os resultados desta pesquisa permitiram a obtenção de equações matemáticas para avaliação da IADP e da TUC do sistema de esgoto da cidade de Borborema que possivelmente poderão ser aplicadas em áreas urbanizadas de outras cidades do mesmo porte. Estimou-se que a IADP pode gerar volumes 2,5 vezes maiores que o volume de esgotos em tempo seco, bem como taxas de infiltração na rede coletora próximas àquelas adotadas para cálculo da rede. O trabalho possibilitou avaliar quão complexos são a infiltração e o afluxo de águas de chuva na rede de esgoto sanitário. Os métodos empregados, tanto de coleta quanto de modelagem, foram muito simples e podem ser aplicados em outras cidades com certa facilidade.

Les routes sont normalement pourvues de systèmes de drainage dimensionnés et exécutés conformément aux règles de l’art en vue d’évacuer, le plus rapidement possible de l’emprise de la route, les eaux des précipitations à considérer sur la base des périodes de retour prises en compte. Toutefois, il subsiste souvent des écoulements d’eau indésirables au niveau des talus et parfois dans les accotements et/ou les surfaces de roulement non imperméabilisées. Une succession de pluies entraîne des infiltrations d’eau qui varient notamment en fonction des conditions climatiques et suivant la texture et la structure du sol. De telles infiltrations ont pour conséquence la réduction des coefficients de sécurité des talus.

Bien qu’il existe plusieurs publications scientifiques traitant de pluies qui ont conduit à des glissements de terrain (Lim et al. 1996 ;Cho et al. 2001 ;Kim et al. 2004 ;Xue et al. 2007 ;Gavin et al. 2008), les incidences des infiltrations résultant de pluies successives sur le comportement des couches superficielles des sols non saturés ne sont généralement pas prises en compte. Les modèles permettant le calcul de la stabilité de talus des massifs de sols non saturés exigent beaucoup de paramètres parfois difficiles à évaluer et se rapportent ordinairement aux cas d’instabilité provoqués par une remontée du niveau piézométrique des nappes phréatiques.

Sur la base des essais réalisés en laboratoire, une méthodologie adaptée permettant d’évaluer la variation spatio-temporelle de la teneur en eau du sol en fonction d’une suite de pluies a été développée. Cette méthodologie facilite la prise en compte des effets cumulés des taux d’infiltration associés aux évènements pluvieux et permet d’en déduire le profil de succion ainsi que celui de la cohésion apparente à utiliser en vue de calculer, pour une inclinaison β du talus, l’intervalle de variation du coefficient de sécurité Fs. La méthodologie développée présente un intérêt particulier dans le cas de budgets et infrastructures limités.

ABSTRACT

Roads are normally equipped with drainage systems sized and implemented in accordance with the rules of art to evacuate as quickly as possible to the right of way, water precipitation to be considered on the basis of return periods taken into account. However, there are often water flows at the slope side and sometimes in the shoulders and / or running surfaces that are not waterproof. A succession of rain causes a certain amount of water infiltration, which varies according to climatic conditions and depending on the soil texture and structure. Such infiltrations have resulted in reduced safety factor of slopes.

Although there are several scientific publications on rainfall leading to landslides (Lim et al. 1996; Cho et al. 2001, Kim et al. 2004; Xue et al. 2007; Gavin and al. 2008), impacts resulting from infiltration of successive rains on the behavior of surface layers of unsaturated soils are usually not taken into account. Models for calculating the slope stability of unsaturated soils require many parameters that can be, in certain circumstances, difficult to assess and refer generally to cases of instability caused by a rise in groundwater level.

Based on laboratory tests, a suitable methodology for assessing the spatial and temporal variation of soil water content induced by a set of rains has been developed. This methodology facilitates the inclusion of the cumulative effects of the infiltration rates associated with rain events and infers from them the profile of suction and that of the apparent cohesion to be used to calculate, for a slope angle β, the range of variation of the safety factor Fs. This methodology is particularly relevant in the case of limited budgets and infrastructures.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

Traditionally, soil scientists have ignored the spatial dimension concentrating upon the physics of soil water movement at points/sites. The development of geographic information systems (GIS) provides an opportunity to develop soil-water models taking into account differences (spatially and temporally) in land cover and soil type. This thesis has attempted to integrate traditional soil water modelling within a GIS for estimating soil water drainage rates for a typical water catchment with spatially varied soil type and land cover. The Campbell soil model has been adopted for its simplicity and accuracy for estimating soil water infiltration/distribution. However, Campbell's model fails to take into account sufficiently the role of vegetation ininfiltration/distribution. The Meteorological Office Rainfall and Evaporation Calculation System provides effective ways of deriving potential evapotranspiration under various vegetated surfaces. The integration of these two models has resulted in the development of the Soil Water Drainage Model which is more accurate and capable of incorporating spatial soil and vegetation data. The model was developed and tested for the south-west Reading study area. The model's behaviour under various conditions was examined and its performance evaluated. It has found that a bare soil surface has a significant water drainage difference from a vegetated one and soil type affects soil drainage rate, especially when the soil is bare or abnormal climatic events occur. It has also shown that grassland reduces greatly the quantity of soil water loss as drainage and most drainage occurred in winter months and early spring. The accuracy of the model's prediction for estimating soil water drainage was validated on the small Winterbourne catchment (45km2) near Newbury, based on the catchment water mass equilibrium. The water drainage rates predicted by the model are reliable and consistent with the observed river discharge data. However, the results suggest a number of ways in which the methodology could be improved.

Acid mine drainage (AMD) forms when sulfur bearing rocks such as pyrite, are exposed to air and water. The oxidation of these minerals leads to the generation of sulfuric acid, which in turn mobilizes metals such as iron, aluminum, manganese, and others. If left untreated, AMD can cause severe harm to the surrounding ecosystem. By law, mining companies are required to treat AMD, often by oxidizing the contaminated water, raising the pH with a chemical additive, and precipitating the metals out of solution. Recent studies at West Virginia University and Virginia Tech have shown that AMD and the treatment precipitates (AMDp) are enriched in rare earth elements (REEs). Given the importance of REEs to modern technology, as well as potential supply restrictions, subsequent research has attempted to identify promising methods to extract and recovery REEs from AMD and AMDp. Prior studies have shown that the physical characteristics of AMDp can vary considerably from site to site, and a robust processes scheme must account for any site-specific disparities. To better understand the inherent variability of AMDp, a scientific study was commissioned to investigate a standard method of characterizing AMDp for the optimization of rare earth extraction processes. The tests developed in this work define the total acid dose needed to dissolve AMDp at various target pH points. Through the course of the study, over 150 unique AMDp samples were evaluated, and comparative analyses were conducted on samples from different sites as well as replicate samples from the same sites. The resultant dataset was analyzed using an empirical model, and a statistical analysis was conducted to correlate the model parameters and other AMDp physical properties. Relationships between elemental assays, moisture, and fitting parameters of the empirical models were found. These results ultimately led to a recommendation for future treatment of AMD and prospective sites.
MS

Several recent studies have shown that acid mine drainage (AMD) may be a promising source of rare earth elements (REEs), which are essential feedstocks for many high tech applications and defense products. AMD is a longstanding environmental challenge and is currently the primary pollutant of water in the Appalachian coal mining region. Acid generated during the coal mining process tends to leach several transition metals from the surrounding rock strata. While iron, aluminum, and manganese have traditionally been noted as the predominant metals in AMD, recent studies have also shown that REEs are also present, albeit in trace concentrations, often less than 5 μg/L. The recovery of REEs from AMD can be both an economic and environmental advantage; however, the low REE concentrations and high contamination from other metals makes the concentration and purification of REEs quite difficult. This research seeks to develop and optimize a process capable of producing mixed rare earth concentrates with purities exceeding 90% from an AMD feedstock. Parallel efforts by other members of the research team showed that a solid preconcentrate, nominally 0.1 to 2% REE, can be readily produced from AMD; however, that pre-concentration process cannot provide the further enrichment needed to generate high purity oxides suitable for downstream markets. In this project, solvent extraction was investigated as secondary process used to further enrich the low grade preconcentrate to a purity exceeding 90%. Initially, laboratory-scale batch solvent extraction tests were performed on synthetic REE solutions to determine the influence of various process parameters (e.g. pH, extractant dosage, diluent type, and feedstock concentration). Next, the separation of REEs from major AMD gangue elements was investigated using synthetic leachate solutions with concentrations similar to those expected from the pre-concentrate samples. This process showed that the grade targets could easily be met when combining optimal parameters from each step. From this preliminary work with synthetic solutions, an optimal SX process was developed and validated using a real leachate generated from a pre-concentrate sample. By integrating leachate preparation, solvent extraction, scrubbing, stripping, and oxalic acid precipitation, an oxide containing 90.5% rare earth oxides was generated. Details on the process development, experimental optimization, and opportunities for process improvement are described.
Master of Science
Rare earth elements (REEs) are essential for many modern industries, high-tech applications, and defense products. The U.S. consumes approximately 11% of the global REE demand; however, the US supply chain is heavily reliant on imported Chinese feedstocks. This lack of a domestic supply chain exposes the US to both price and supply volatility, which are prevalent in the international markets. This supply issue is further compounded by a lack of suitable domestic feedstocks. REEs are rarely concentrated into mineable ore deposits, and in some cases the extraction and processing of conventional REEs deposits entails considerable environmental risk. As a result of these challenges, numerous federal agencies and private companies have recently sought to identify promising alternative resources. One potential alternative resource is acid mine drainage (AMD), which is a common environmental challenge associated with coal and hard rock mining. Prior studies have shown that acid mine drainage contains REEs; however, other metals, such as iron, aluminum, and manganese, preclude REE recovery using conventional processing techniques. As such, the goal of this research is to develop and optimize a process capable of recovering and concentrating REEs from an AMD feedstock. The research conducted in this thesis predominantly included laboratory testing using synthetic AMD samples. The complexity of the synthetic AMD progressively increased from very simple, single element solutions to complex multi-component mixtures. Through this research, data and information from these controlled experiments was used to design a multi-step solvent extraction process capable of producing final REE products exceeding 90% purity. In the last stage of the research, the final process was validated using actual AMD recovered from an operating mine site. The validation test showed that the process was effective in meeting its initial objectives: the grade of the final rare earth oxide was determined to be 90.5%. This laboratory-scale experimental work represents the first step of process needed to develop and deploy a commercial technology capable of producing REE products from AMD feedstocks.

Coal has been an important natural resource of energy in the Illinois Basin for generations. In addition to the organic macerals in coal, there is inorganic matter containing minerals and trace elements. With growing demand for economic and critical metals including Rare Earth Elements and Yttrium (REY), coals containing anomalously high concentrations of trace elements, as well as their associated coal mine wastes, and drainages have been explored as promising secondary resources, but there were no former studies of REY in Illinois basin CMD. CMD samples were collected from 35 abandoned coal mine sites from three regions of the Illinois basin. Region 1 (R1) the southern extent of the basin extending west along the cottage grove fault system and includes Hicks dome, a nexus of regional hydrothermal activity and provenance of the Illinois Kentucky Fluorite District (IKFD) ore deposits; Region 2 (R2) comprised locations situated in western Illinois along the Du Quoin Monocline; and Region 3 (R3) comprised locations situated in northern Illinois, farthest from the Hicks Dome. Two hypotheses were tested in this study: (1) that pH and ΣREY would share an inverse correlation, with the greatest abundances of REY found in the most acidic drainages; and (2) hydrothermal activity associated with Hicks Dome in southern Illinois was the source of REY enrichment in the coals, and so, REY abundance and pattern would reflect proximity to the cryptoexplosive complex, with the greatest enrichments expected in R1, closest to Hicks Dome. The geochemical data of 42 CMD samples was examined was analyzed to test these two ii hypotheses. Samples ranged from extremely acidic (pH=1.93) to circumneutral (pH=7.6) with an average pH value of 3.4. Total REY values (ΣREY) averaged 1,057 μg/L across all samples and ranged from 0.4-9,879 μg/L while Σcritical-REY abundances (Nd, Eu, Tb, Dy, and Y) averaged 611 μg/L and ranged from 0.2-7,213 μg/L. Furthermore, there are significant direct correlations of ΣREY with Al, Si, SO4, Zn, Ni, Cu, Cd, Co and no correlations with Fe, Ca, P, Ba, and V. In the course of investigation, it was found that pH and linear concentration values for REY correlate poorly. However, logarithmic values of REY concentrations (i.e., log[ΣREY]), as well as the above trace metals have strong inverse correlations with pH( (r=- 0.84, p

Mining activities, as essential as they are for our economy and our society, bring pollutants such as acid mine drainage (AMD) which contains dissolved metal(loid)s into the environment. There are different technologies currently being practiced to treat AMD, but many of these methods are prohibitive in industry due to high energy, material and labor requirements. This study investigated two emerging technologies to treat AMD with high removal rates of some metals. In addition, as AMD contains strategic metals such as rare earth elements (REEs), hydrometallurgical and biosorptive approaches were used to recover REEs from AMD, hydrometallurgical recovery method was also applied for coal by-products for the method developed. A two-chamber bioelectrochemical system (BES) was used to remove different types of metals from AMD. After 7 days, the pH of the cathode solution increased from 2.5 to 7.3. More than 99% of Al, Fe and Pb were removed, and removal rates of 93%, 91%, 89% and 69% were achieved for Cd, Zn, Mn, and Co, respectively, at the biocathode. Energy-dispersive X-ray spectroscopy (EDS) studies revealed the deposition of the various metals on the cathode surface, and some metals were detected in precipitates from the cathode chamber. During the BES operation, ~30-50 mV of closed circuit voltage was obtained for different conditions. A single-chambered BES study was conducted for the removal of Cd, Ni, and Mn in mine drainage. Compared to a double chamber, a single chamber BES is easier to design and operate. The removal process was studied with activated sludge from a local wastewater treatment plant. The effect of applied voltage, time, and initial concertation of these metals on their removal rate was studied. For Cd initial concentrations of 625 and 165 µg/L, 1.0 V showed the highest removal efficiency, and ~93 and 95% of Cd were removed, respectively. For a Ni initial concentration of 2,440 µg/L, 72% was removed under 1.0 V compared to the control of 77%. However, for a lower initial Ni concentration of 190 µg/L, 1.0 V was better compared than other conditions, and it removed 92% of Ni. For a Mn initial concentration of 1,800 µg/L, 1.0 V had a better result, however, only ~19% of the Mn was removed. For a lower Mn initial concentration of 390 µg/L, 1.0 V was favorable only at 24 h and the removal rate was ~37%. Nanoscale zerovalent iron (nZVI) was used to remove contaminants from AMD. These contaminants include transition metals (Co, Ni, Cu, Mn, and Zn), alkali and alkaline earth metals (Li, Mg, and Ca), metalloid (As), nonmetals (Se and S), and active metal (Al). Purchased nZVI in concentrations of 10-6500 mg/L was used for a reaction duration of up to 480 min. The pH of the AMD increased linearly with increasing concentrations of nZVI, with a maximum of 6.0±0.1 at 6500 mg/L of nZVI. Cu and Al had the highest removal rate among all other elements. With 10 mg/L of nZVI, ~100% of Cu was removed within 120 min. Up to ~98% of Al was removed with 5000 mg/L of nZVI in 480 min. Reuse of the purchased nZVI was studied for the first time for AMD treatment; however, after reuse in the second cycle, the nZVI was no longer effective. Lab-made nZVI by the precipitation method was tested for a longer time of 48 h. Removal rates for different elements did not change after ~8 h (e.g., 480 min), and in general, the lab-made nZVI had better removal efficiency compared to the purchased nZVI, with removal rate of ~28-79% when using 80 mg/L of the lab-made nZVI. Besides Cu, Al, Ni, and Co, successful removal of Mg and Ca, as well as S, Co, Li, As, and Se from AMD was reported for the first time by using nZVI. Different coal ranks were examined for REE concentration from coal ash. Maximum REE content of more than 700 mg/kg was observed for the highest-rank coal (anthracite) sample, and that was used for leaching and recovery studies. Hydrometallurgical processes including leaching, solvent extraction, stripping, and precipitation were performed to recover REEs from coal ash. Nitric acid leaching tests were conducted at 95 ℃ using a 4×2×2 factorial design. The results indicated that the highest rate of light REEs (LREEs) recovery was achieved at the highest molarity of the acid solution, lowest solids content and longest retention time. However, the highest rate of heavy REEs (HREEs) recovery needed only an intermediate level of acid molarity. The highest recovery rates of 90% for LREEs and 94% for HREEs were obtained. Recirculation of the leachate was conducted to prepare the REE-concentrated solution for the solvent extraction. After two stages of leaching, a 33 mg/L of TREE concentration was obtained in the leachate. Solvent extraction (SX) tests conducted using three different extractants, namely, TBP, D2EHPA and Cyanex 572, and their combinations showed that D2EHPA was the best extractant for recovering REEs from the nitric acid leachate solution with an extraction efficiency of 99%. Nitric acid and sulfuric acid and their mixture were used in the stripping tests. The effect of solvent concentration (in the SX process) was also studied in the stripping stage. When 50% solvent concentration was used, a maximum of 58% stripping recovery was obtained. Oxalic acid helped precipitate ~94% of total REEs (TREEs) from the above aqueous solution. Calcination of the product was performed to reach a final product of 0.8% rear earth oxides (REOs). The same process flowsheet was also successfully tested for another coal ash sample. To recover REEs from AMD, two different approaches were carried out including hydrometallurgical technique and more environmentally friendly approach- biosorptive recovery. A complete process flowsheet including either solvent extraction or biosorption, followed by stripping, and precipitation was developed to recover REEs from an unconventional source of AMD for the first time. At the natural pH of 2.5 almost all REEs were extracted from the solution. Metal-loaded organic solution was reused for three cycles, and it was shown that after three cycles, there was no major reduction in the capacity of the extractant. Striping with 6.0 M HNO3 recovered 23.9±0.7, 74.7±2.1, and 53.1±1.4% of LREEs, HREEs, and TREEs from the organic phase accordingly. Using oxalic acid, and for pH of 2.0, 92.9±2.8% of LREEs, 10±1.5% of HREEs, and 56.2±1.8% of TREEs were precipitated. In the biosorptive extraction, >99% of TREEs were extracted from the solution. The REE-bearing bacteria was also stripped with 6.0 M HNO3, 2871.3±114.8 µg/L (45.0±1.8%) LREEs, 3851.0±154.0 µg/L (65.0±2.6%) HREEs, and 6722.0±268.9 µg/L (50.0±2.0%) TREEs were obtained. Both hydrometallurgical and biosorptive methods extracted almost all of the REEs in the AMD, though pH was adjusted to 4.0 for the biosorptive method. After stripping, comparable amounts of TREEs were obtained by both methods.

Thesis (M.S.)--West Virginia University, 2008.
Title from document title page. Document formatted into pages; contains vii, 67 p. : ill. (some col.), col. maps. Includes abstract. Includes bibliographical references.

La plaine du Gharb au Maroc, souffre d'excès d'eau pendant l'hiver et du déficit hydrique en été. Cet état de fait explique la faible rentabilité des investissements hydro agricoles réalisés à ce jour par le gouvernement. L'originalité de ce travail réside dans le fait de relier l'évacuation des eaux de surface excédentaires au cours de l'hiver, et la satisfaction des besoins en eau de la culture dès le printemps où elle commence à connaître un déficit hydrique.
Deux objectifs sont assignés à ce travail : (i) l'évaluation des performances hydrauliques et agronomiques du drainage de surface et (ii) l'évaluation de l'impact de l'excès d'eau sur la culture de la betterave à sucre. Il repose sur (i) une approche expérimentale et (ii) une modélisation des processus en question. Pour ce faire, des comparaisons ont été effectuées entre trois parcelles : (i) une parcelle nivelée selon une pente S0 de 0.2 % et irriguée à la raie, (ii) une parcelle non nivelée irriguée par aspersion et (iii) une parcelle nivelée selon une pente S0 de 0.2% dans la même sens que la première parcelle mais dépourvue de raies et irriguée par aspersion.
L'étude expérimentale a clairement démontré la capacité d'une parcelle avec raies à évacuer efficacement les excès d'eau pendant l'hiver comparativement à une parcelle non nivelée. Sur cette dernière, les submersions locales affectent fortement la production de la betterave à sucre. Le système de raies fournit les meilleurs rendements suivis de près par le système nivelé irrigué par l'aspersion.
Un modèle de ruissellement a été spécifiquement développé pour la prédiction du volume ruisselé et du débit maximal de ruissellement à l'exutoire d'une parcelle avec raies soumise à des événements pluvieux intermittents et d'intensités variables. Ce modèle utilisant entre autre pour entrée le hyetogramme de pluie d'une période de retour 1 an met en évidence le sous dimensionnement des fossés destinés à recueillir les eaux à l'aval des parcelles chez les agriculteurs. Les performances agronomiques de la raie ont été évaluées à l'aide du modèle SOFIP qui simule l'impact de l'irrigation à la raie sur la productivité de l'eau. Pour la parcelle non nivelée, le modèle PILOTE a été adapté pour simuler l'impact de la submersion sur la productivité de la betterave à sucre. Les simulations du rendement effectuées sur une série de onze années montrent clairement l'avantage du système gravitaire modernisé par rapport au système aspersif non nivelé et ce, pour différentes dates de semis. On peut pour conclure affirmer que le développement agricole dans la plaine du Gharb doit être raisonné en tenant compte des excès d'eau hivernaux préjudiciables aux cultures.

Magister Scientiae - MSc (Environ & Water Science)
There are growing concerns around the environmental issues related to processed water as the demand for potable water is on the increase in South Africa. Effluents discharged from various sectors such as water treatment facilities pose a constant threat to the environment and natural water resources, including rivers and groundwater due to their poor chemical and physical composition. As a result, the demand for predicting the elevated concentrations of salts in a spatial and temporal dimension is constantly growing. The effluent at the eMalahleni water reclamation plant in Mpumalanga, South Africa, is being processed through a triple reverse osmosis that improves the water quality of the mine water to potable standards. Two water quality streams emerge from this process, i.e. a potable standard and the other a brine concentrate which is stored in ponds. Brine ponds are used for inland brine disposal in the eMalahleni water reclamation plant. The large volumes and limited capacity to store brines has placed great emphasis on enhanced evaporation rates to increase the efficiency of the ponds. In order to improve the rate of brine evaporation in the pond, an understanding of the effect of brine salt content and other parameters affecting the rate of evaporation is required. This study aimed at establishing the physical and chemical behaviour of the brine from the eMalahleni plant in a controlled environment. The investigation incorporated actual brine from the eMalahleni plant as well as synthetic salts typical of the major components of the eMalahleni brine.

Land application of wastes has become increasingly popular, to promote nutrient recycling and environmental protection, with soil functioning as a partial barrier between wastes and groundwater. Dairy shed effluent (DSE), may contain a wide variety of pathogenic micro-organisms, including bacteria (e.g. Salmonella paratyphyi, Escherichia coli. and Campylobacter), protozoa and viruses. Groundwater pathogen contamination resulting from land-applied DSE is drawing more attention with the intensified development of the dairy farm industry in New Zealand. The purpose of this research was to investigate the fate and transport of bacterial indicator-faecal coliform (FC) from land-applied DSE under different irrigation practices via field lysimeter studies, using two water irrigation methods (flood and sprinkler) with contrasting application rates, through the 2005-2006 irrigation season. It was aimed at better understanding, quantifying and modelling of the processes that govern the removal of microbes in intact soil columns, bridging the gap between previous theoretical research and general farm practices, specifically for Templeton soil. This study involved different approaches (leaching experiments, infiltrometer measurements and a dye infiltration study) to understand the processes of transient water flow and bacterial transport; and to extrapolate the relationships between bacterial transport and soil properties (like soil structure, texture), and soil physical status (soil water potential ψ and volumetric water content θ). Factors controlling FC transport are discussed. A contaminant transport model, HYDRUS-1D, was applied to simulate microbial transport through soil on the basis of measured datasets. This study was carried out at Lincoln University’s Centre for Soil and Environmental Quality (CSEQ) lysimeter site. Six lysimeters were employed in two trials. Each trial involved application of DSE, followed by a water irrigation sequence applied in a flux-controlled method. The soil columns were taken from the site of the new Lincoln University Dairy Farm, Lincoln, Canterbury. The soil type is Templeton fine sandy loam (Udic-Ustochrept, coarse loamy, mixed, mesic). Vertical profiles (at four depths) of θ and ψ were measured during leaching experiments. The leaching experiments directly measured concentrations of chemical tracer (Br⁻ or Cl⁻) and FC in drainage. Results showed that bacteria could readily penetrate through 700 mm deep soil columns, when facilitated by water flow. In the first (summer) trial, FC in leachate as high as 1.4×10⁶ cfu 100 mL⁻¹ (similar to the DSE concentration), was detected in one lysimeter that had a higher clay content in the topsoil, immediately after DSE application, and before any water irrigation. This indicates that DSE flowed through preferential flow paths without significant treatment or reduction in concentrations. The highest post-irrigation concentration was 3.4×10³ cfu 100 mL⁻¹ under flood irrigation. Flood irrigation resulted in more bacteria and Br⁻ leaching than spray irrigation. In both trials (summer and autumn) results showed significant differences between irrigation treatments in lysimeters sharing similar drainage class (moderate or moderately rapid). Leaching bacterial concentration was positively correlated with both θ and ψ, and sometimes drainage rate. Greater bacterial leaching was found in the one lysimeter with rapid whole-column effective hydraulic conductivity, Keff, for both flood and spray treatments. Occasionally, the effect of Keff on water movement and bacterial transport overrode the effect of irrigation. The ‘seasonal condition’ of the soil (including variation in initial water content) also influenced bacterial leaching, with less risk of leaching in autumn than in summer. A tension infiltrometer experiment measured hydraulic conductivity of the lysimeters at zero and 40 mm suction. The results showed in most cases a significant correlation between the proportion of bacteria leached and the flow contribution of the macropores. The higher the Ksat, the greater the amount of drainage and bacterial leaching obtained. This research also found that this technique may exclude the activity of some continuous macropores (e.g., cracks) due to the difference of initial wetness which could substantially change the conductivity and result in more serious bacterial leaching in this Templeton soil. A dye infiltration study showed there was great variability in water flow patterns, and most of the flow reaching deeper than 50 cm resulted from macropores, mainly visible cracks. The transient water flow and transport of tracer (Br⁻) and FC were modelled using the HYDRUS-1D software package. The uniform flow van Genuchten model, and the dual-porosity model were used for water flow and the mobile-immobile (MIM) model was used for tracer and FC transport. The hydraulic and solute parameters were optimized during simulation, on the basis of measured datasets from the leaching experiments. There was evidence supporting the presence of macropores, based on the water flow in the post-DSE application stage. The optimised saturated water content (θs) decreased during the post-application process, which could be explained in terms of macropore flow enhanced by irrigation. Moreover, bacterial simulation showed discrepancies in all cases of uniform flow simulations at the very initial stage, indicating that non-equilibrium processes were dominant during those short periods, and suggesting that there were strong dynamic processes involving structure change and subsequently flow paths. It is recommended that management strategies to reduce FC contamination following application of DSE in these soils must aim to decrease preferential flow by adjusting irrigation schemes. Attention needs to be given to a) decreasing irrigation rates at the beginning of each irrigation; b) increasing the number of irrigations, by reducing at the same time the amount of water applied and the irrigation rate at each irrigation; c) applying spray irrigation rather than flood irrigation.

Worldwide there is considerable concern over the effects of human activities on the quantity and quality of freshwater. Measurement of infiltration behaviour will be important for improving freshwater management. This study identifies that New Zealand has a sporadic history of measuring soil water movement attributes on a limited number of soil types, although the current practical demand should be large for management of irrigation, dairy farm effluent disposal, as well as municipal / domestic waste- and storm-water disposal. Previous research has demonstrated that infiltration behaviour is governed by the interplay between numerous mechanisms including hydrophobicity and preferential flow, the latter being an important mechanism of contaminant leaching for many NZ soils. Future characterisation will need to recognise the dynamic nature of these interactions, and be able to reliably characterise the key infiltration mechanisms. Since macropores are responsible for preferential flow, it is critical that infiltration studies use a representative sample of the macropore network. The aim of this project was to study the mechanisms governing the infiltration behaviour of a layered soil in large (50 x 70 cm) monolith lysimeters, where the connectivity of the macropore network remains undisturbed. Four lysimeters of the Gorge silt loam were collected, a structured soil with four distinct layers. On each lysimeter there were four separate infiltration experiments, with water applied under suctions of 0, 0.5, 1, and 1.5 kPa by a custom-built tension infiltrometer. Each lysimeter was instrumented with 30 tensiometers, located in arrays at the layer boundaries. There was also a field experiment using ponded dye infiltration to visually define preferential flowpaths. Analysis of dye patterns, temporal variability in soil matric potential (Ψm), and solute breakthrough curves all show that preferential flow is an important infiltration mechanism. Preferential flowpaths were activated when Ψm was above -1.5 kPa. During saturated infiltration, at least 97% of drainage was through the ‘mobile’ pore volume of the lysimeter (θm), estimated among the lysimeters at 5.4 – 8.7 % of the lysimeter volume. Early-time infiltration behaviour did not show the classical square-root of time behaviour, indicating sorptivity was not the governing mechanism. This was consistent across the four lysimeters, and during infiltration under different surface imposed suctions. The most likely mechanism restricting sorptivity is weak hydrophobicity, which appears to restrict infiltration for the first 5 – 10 mm of infiltration. Overall, the Gorge soil’s early-time infiltration behaviour is governed by the dynamic interaction between sorptivity, hydrophobicity, the network of air-filled pores, preferential flow and air encapsulation. Long-time infiltration behaviour was intimately linked to the temporal dynamics of Ψm, which was in turn controlled by preferential flow and soil layer interactions. Preferential flowpaths created strong inter-layer connectivity by allowing an irregular wetting front to reach lower layers within 2 – 15 mm of infiltration. Thereafter, layer interactions dominate infiltration for long-time periods, as Ψm in soil layers with different K(Ψm) relationships self-adjusts to try to maintain a constant Darcy velocity. An important finding was that Ψm rarely attained the value set by the tension infiltrometer during unsaturated infiltration. The results show that ‘true’ steady-state infiltration is unlikely to occur in layered soils. A quasi-steady state was identified once the whole column had fully wet and layer interactions had settled to where Ψm changes occurred in unison through each soil layer. Quasi-steady state was difficult to identify from just the cumulative infiltration curve, but more robustly identified as when infiltration matched drainage, and Ψm measurements showed each layer had a stable hydraulic gradient. I conclude that the in-situ hydraulic conductivity, K(Ψm), of individual soil layers can be accurately and meaningfully determined from lysimeter-scale infiltration experiments. My results show that K(Ψm) is different for each soil layer, and that differences are consistent among the four lysimeters. Under saturated flow the subsoil had the lowest conductivity, and was the restricting layer. Most interestingly this pattern reversed during unsaturated flow. As Ψm decreased below -0.5 to -1 kPa, the subsoil was markedly more conductive, and the topsoil layers became the restricting layers. All four soil layers demonstrate a sharp decline in K(Ψm) as Ψm decreases, with a break in slope at ~ -1 kPa indicating the dual-permeability nature of all layers.

La nécrose pancréatique est responsable, du fait de ses conséquences loco-régionales et systémiques, de la gravité des pancréatites aiguës. Nos travaux expérimentaux ont étudié in vivo chez le rat le rôle supposé d 'une production d’acides gras libres (AGL) toxiques par la lipase libérée, dans la genèse de la nécrose pancréatique, rôle établi jusqu'alors par des travaux réalisés in vitro. La majoration artificielle des taux d 'AGL circulants n'a pas aggravé les pancréatites œdémateuses à la céruléine. Aucune libération spontanée d'AGL n'a été mise en évidence dans la circulation périphérique ou portale, ou dans le tissu pancréatique, malgré une libération massive de lipase pancréatique par la pancréatite. Au cours des pancréatites nécrosantes induites par perfusion rétrograde de taurocholate, seule une libération très précoce et transitoire d'AGL a été observée dans la cavité péritonéale (ascite), non corrélée à l'évolution des taux de lipase et non modifiée par l'injection intra-péritonéale d'un inhibiteur spécifique de la lipase pancréatique : la Tétrahydrolipstatine®. Ces AGL intrapéritonéaux pourraient résulter de la lyse cellulaire induite par l'action détergente du taurocholate L'existence d'une production délétère d'AGL par la lipase pancréatique au cours de la pancréatite aiguë n'est donc pas confirmée in vivo. Nos travaux cliniques ont permis d'établir 1- qu'une nécrosectomie réglée suivie d'irrigation prolongée permet d'obtenir, même en cas de réintervention, un drainage efficace de la nécrose pancréatique ; 2- que le drainage percutané des collections stérile, favorise leur surinfection et n'assure pas la guérison des patients ; 3- que la surinfection de la nécrose augmente la fréquence des défaillances viscérales mais non leur gravité, et que la seule réanimation des pancréatites avec défaillance viscérale dont la nécrose reste stérile permet d’obtenir une dans ce sous groupe une faible mortalité
Pancreatic necrosis is responsible for the severity of acute pancreatitis because of its systemic and locoregional consequences. Our experimental work assessed in vivo in rat the role of Free Fatty Acids (FFA) released by pancreatic lipase which implication in the necrotizing process was up to now assumed on the basis of in vitro studies. A provoked increase of circulating FFA levels did not worsened the courseof edematous cerulein-induced pancreatitis. No spontaneous release of FFA ocurred, neither in systemic or portal circulation, nor in pancreatic tissue, despite a large release of pancreatic lipase caused by pancreatitis. In necrotizing pancreatitis induced by retrograde infusion of taurocholate, an early and transient release of FFA was only observed in peritoneal cavity (in ascites), not correlated with the course of lipase levels in ascites and not altered by the infra-peritoneal injection of the specifie lipase inhibitor : Tetrahydrolipstatin®. These intra-peritoneal FFA could result from a celllysis induced by the detergent properties of taurocholate. The previously supposed deleterious release of FFA by the released pancreatic lipase during pancreatitis does not seem to occur in vivo. Our clinical work has demonstrated 1- the value of a formal technique of necrosectomy associated with prolonged post-operative irrigation of the necrotic sites, providing efficient drainage of pancreatic necrosis in previously operated patients; 2- the insufficiency of percutaneous drainage of sterile collections favouring their super-infection without curing the patients; 3- the role of super-infection of pancreatic necrosis increasing the frequency of organ failures but not their severity, and the value of a conservative management of sterile necrosis, yielding low mortality rates in this sub-group

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Durante a exploração de uma mina, vários impactos são causados no meio ambiente, entre eles a geração da drenagem ácida de minas (DAM), que consiste da exposição de minerais sulfetados ao ar, água e microorganismos do tipo ferroxidantes, apresentando reações de oxidação e formação de ácido sulfúrico solubilizando metais ali presentes contaminando o solo e as águas. O objetivo deste trabalho de pesquisa foi estudar uma solução tecnológica fazendo uso da oxidação avançada com ozônio de metais pesados presentes em efluentes contaminados, em mina de urânio, com especial foco na remoção do manganês. A mina de urânio das Indústrias Nucleares do Brasil INB, em Caldas, Minas Gerais, local de aplicação deste estudo, enfrenta o problema da DAM e tem como principais contaminantes de suas águas superficiais os elementos, alumínio (Al), manganês (Mn), zinco (Zn), ferro (Fe), sulfatos (SO4+2), fluoretos (F-), metais de terras raras, alem do urânio (U) e do tório (Th). Os testes com ozônio realizados em laboratório com os efluentes da INB e in situ, mostraram uma grande eficiência para remoção do ferro, manganês e cério em até 99%. A concentração total de manganês ficou abaixo dos limites estabelecidos pela resolução 430 e 357 do CONAMA. Elementos como neodímio (Nd), lantânio (La) e zinco (Zn) pouco se oxidam com O3. O Al se mantém praticamente inalterado, enquanto que o tório e o urânio decaem, mas com o passar do tempo de ozonização voltam a se concentrar, porém com um valor inferior ao inicial. O precipitado obtido após a ozonização consiste de até 85% de oxido de manganês. A fim de descartar, após a ozonização, o efluente líquido para o ambiente é necessário uma correção do pH, de modo a atender os parâmetros da legislação CONAMA, sendo utilizado 50 a 86% menos reagente (CaOH2), do que as quantidades utilizadas no processo adotado pela INB.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

Controls on denudation in the eastern Bolivian Andes are evaluated by synthesis of new and existing denudation estimates from basin-morphometry, stream - powered fluvial incision, landslide mapping, sediment flux, erosion surfaces, thermochronology, foreland basin sediment volumes, and structural restorations. Centered at 17.5 °S, the northeastern Bolivian Andes exhibit high relief, a wet climate, and a narrow fold- thrust belt. In contrast, the southeastern Bolivian Andes have low relief, a semi-arid climate, and a wide fold-thrust belt. Basin -morphometry indicates a northward increase in relief and relative denudation. Stream-power along river profiles shows greater average incision rates in the north by a factor of 2 to 4. In the south, profile knickpoints with high incision rates are controlled by fold-thrust belt structures such as the surface expressions of basement megathrusts, faults, folds, and lithologic boundaries. Landslide and sediment-flux data are controlled by climate, elevation, basin morphology, and size and show a similar trend; short -term denudation-rate averages are greater in the north (1- 9 mm/yr) than the south (0.3-0.4 mm/yr). Long-term denudation-rate estimates including fission track, basin fill, erosion surfaces, and structural restorations also exhibit greater values in the north (0.2-0.8 mm/yr) compared to the south (0.04-0.3 mm/yr). Controls on long-term denudation rates include relief, orographic and global atmospheric circulation patterns of precipitation, climate change, glaciation, and fold-thrust belt geometry and kinematics. The denudation synthesis supports two conclusions: 1) denudation rates have increased towards the present 2) an along-strike disparity in denudation (greater in the north) has existed since at least the Miocene and has increased towards the present. Denudation rates and controls suggest that Bolivian mountain morphology is controlled by both its orientation at mid-latitude, and the feedbacks between uplift, kinematics, orographic effects on precipitation, glaciation, and the increased erosion that accompanies orogenesis.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1985.
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碩士
東方設計大學
時尚美妝設計系
106
The hectic pace of today's intense lifestyle is likely to cause people stressful more than ever. When our body is under pressure, we usually seek for a remedy to relieve stress; aromatherapy is a popular choice we make to relax our body and mind. This research is basically a study of the influence of essence oils and manual lymphatic drainage upon the heart rate variability (HRV) of autonomic nerve. This research is in the quasi-experimental design, and the cases are sampled purposely and grouped randomly. According to the questionaires, the aromas of the essence oils and MLD are favored by the subjects in the study and are conducive to relaxation of the mood and muscles and decreasing anxiety. The statistical analysis of the SPSS shows that the P values of the mean differences of the psychosomatic stress indexes, the migraine symptoms, and the tension muscles of the shoulders, neck and lower back of subjects in the study were less than 0.001 (***P<0.001), which indicates the results were statistically highly significant. As to the HRV experiments: in both the MLD group and the experimental group(applying the essence oils of sweet orange, lime and bergamot with MLD), their statistics of the high frequency (HF), the percentage of the high frequency (HF%), the low frequency (LF), the percentage of the low frequency (LF%), the ratio of sympathetic/parasympathetic nerve to LF/HF were all getting improved after being tested. However, after being analyzed by SPSS, in the 4 experiments, only the mean differences of HF and the ratio of sympathetic/parasympathetic nerve to LF/HF were at the level of *P<0.05 and statistically significant, while the mean differences of the others were less than statistically significant. From the result of this research, it indicates that the effects of MLD as well as the essence oils of sweet orange , lime and bergamont are perceivable. They are capable of reducing sympathetic nervous activity, improving parasympathetic nervous activity, relaxing body, relieving stress, bettering sleeping quality, alleviating uncomfortableness, enhancing autonomic nervous activity, beating fatigue and promoting quality of life.

The age of “easy” oil has steadily declined through the years as many conventional land-based fields have been depleted to residual levels. Novel technologies, however, have reawakened old fields, allowing incremental oil to be added to their recoverable oil in place (ROIP). Underground Gravity Drainage (UGD), an example of one of these technologies, combines improved horizontal and deviated drilling technologies with the longstanding concept of gravity drainage. In this work, a better understanding of gravity drainage has been gained through (1) development of a numerical, three-dimensional, three-phase reservoir simulator (UT-EMPRES), (2) development of a universal, semi-empirical model of production rates through primary depletion, and (3) analysis of the important aspects of gravity drainage through simulation. UT-EMPRES is a new three-phase, finite-difference reservoir simulator, which utilizes a simple, easy-to-use Microsoft Excel interface to access MATLAB-programmed simulation code. This simulator produces nearly identical results to other well-established simulators, including UTCHEM and CMG. UT-EMPRES has some unique features, allows for easy post-processing in MATLAB, and has been utilized extensively in the other two areas of this thesis. The generalized flow rate model (GFRM) is a semi-empirical equation that is used to forecast the dynamic primary production rate of a reservoir with an arbitrary number of wells all operating at the same constant pressure condition. The model is an extension of the classic tank model, which is inherently a single flowing phase development. With the ability to make a priori predictions of production figures, users can screen various prospect assets on the basis of economic potential through optimization routines on the GFRM. Gravity drainage and its approximation through numerical simulation are analyzed. A sensitivity study was conducted on three-phase gravity drainage, leading to the conclusion that small changes in vertical permeability and portions of the relative permeability-saturation relationships can greatly affect production rates. Finally, two-phase (oil and air) and regions of three-phase (water, oil, air) flow simulations were found to exhibit exponential decline in phase production rates, which may enable the GFRM to be applicable to UGD-type processes.
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This paper aims to investigate experimentally the effects of circulating coolant flow rate, groundwater table fluctuations, infiltration of rainwater, on the amount of thermal energy that can be recovered from the near surface soil layers. A comprehensive experimental investigation was carried out on a fully equipped tank filled with sand. A heat collector panel was embedded horizontally at the mid-height of the tank. Measurements of the temperature at various points on the heat collector panel, adjacent soil, inlet and outlet were continuously monitored and recorded. After reaching a steady state, it was observed that increasing water saturation in the adjacent soil leads to a substantial increase on the amount of heat recovered. A model was proposed for the estimation of temperature along the heat collector panel based on steady state conditions. It accounted for thermal resistance between pipes and the variability of water saturation in the adjacent soils. This model showed good agreement with the data. Whilst increasing the flow rate of the circulating fluid within the panel did not cause noticeable improvement on the amount of heat energy that can be harnessed within the laminar flow regime commonly found in ground source heat panels. Infiltration of rainwater would cause a temporary enhancement on the amount of extracted heat. Measurement of the sand thermal conductivity during a cycle of drying and wetting indicates that the thermal conductivity is primarily dependent upon the degree of water saturation and secondary on the flow path.

Thesis (M.S.)--University of Wisconsin--Madison, 2003.
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For effective reservoir management and production optimization, it is important to understand drained volumes, pressure depletion and reservoir well rates at all flow times. For conventional reservoirs, this behavior is based on the concepts of reservoir pressure and energy and convective flow. But, with the development of unconventional reservoirs, there is increased focus on the unsteady state transient flow behavior. For analyzing such flow behaviors, well test analysis concepts are commonly applied, based on the analytical solutions of the diffusivity equation. In this thesis, we have proposed a novel methodology for estimating the drainage volumes and utilizing it to obtain the pressure and flux at any location in the reservoir. The result is a semi-analytic calculation only, with close to the simplicity of an analytic approach, but with significantly more generality. The approach is significantly faster than a conventional finite difference solution, although with some simplifying assumptions. The proposed solution is generalized to handle heterogeneous reservoirs, complex well geometries and bounded and semi-bounded reservoirs. Therefore, this approach is particularly beneficial for unconventional reservoir development with multiple transverse fractured horizontal wells, where limited analytical solutions are available. To estimate the drainage volume, we have applied an asymptotic solution to the diffusivity equation and determined the diffusive time of flight distribution. For the pressure solution, a geometric approximation has been applied within the drainage volume to reduce the full solution of the diffusivity equation to a system of decoupled ordinary differential equations. Besides, this asymptotic expression can also be extended to obtain the well rates, producing under constant bottomhole pressure constraint. In this thesis, we have described the detailed methodology and its validation through various case studies. We have also studied the limits of validity of the approximation to better understand the general applicability. We expect that this approach will enable the inversion of field performance data for improved well and/or fracture characterization, and similarly, the optimization of well trajectories and fracture design, in an analogous manner to how rapid but approximate streamline techniques have been used for improved conventional reservoir management.

碩士
國立中央大學
應用地質研究所
105
Large landslide usually causes loss of life and property. The slip rate, drainage condition and shear displacement control the frictional characteristics of slip zone. Moreover, the effective stress of slip zone decreases with increasing pore pressure. The strength of slip zone is controlled by the slip rate and pore pressure. To know the relation between the frictional characteristics and previous parameters contribute to research of landslide prevention. This study aims at exploring the influence of slip rates and drainage conditions on the strength of kaolin clay. A low to high velocity rotary shear apparatus was used to measure the apparent friction coefficient of wet kaolin clay under a normal stress of 1 MPa and slip rate ranged from 10-7 to 1 m/s. The drainage conditions are controlled by alloy holders including radial, single and double drainage conditions. The experimental results show: (a) the steady-state friction coefficients at radial drainage condition under slip rates from 10-7 to10-1 m/s (slip-strengthening behavior) ranged from 0.25 to 0.58 and under 1 m/s of slip rate (slip-weakening behavior) is 0.08 and; (b) the steady-state friction coefficients single drainage condition under slip rates from 10-6 to10-1 m/s (slip-strengthening behavior) ranged from 0.30 to 0.4 and under 1 m/s of slip rate (slip-weakening behavior) is 0.18; (c) the steady-state friction coefficients double drainage condition under slip rates from 10-6 to10-1 m/s (slip-strengthening behavior) ranged from 0.18 to 0.58. Besides, the friction coefficient at radial drainage condition under slip rates from 10-6 to10-2 m/s dropped rapidly (before slip displacements < 2 m) after first peak and increased again after the drop, which represents the excess pore pressure was induced and dissipated at the initial stage, especially. Calculate the temperature change during the course of the radial drainage and dry test conditions. At the slip rate of 1 m/s test, the test temperature of the radial drainage test specimen is up to 72 degrees; the test temperature of the dry test specimen is even up to 188 degrees. At the slip rate of 10-1 m/s test, the final temperature of the experiment range from 56 to 65 degrees. At slip rate of 10-2 m/s test, the temperature change in the experiment does not exceed 8 degrees. According to the above results and previous studies can determine the excess pore pressure generation mechanism: (1) Pore volume compression and pore pressure generation. (2) The rise in temperature leads to pore water generation. (3) Water vaporization leads to pore water generation. The results could be applied to the study of large landslide from creeping tuning into catastrophic failure. Therefore, the accumulation of excess pore pressure is related to different drainage conditions and slip rates. It is pointed out that the drainage condition of the sliding surface will affect the acceleration of the sliding surface. If the sliding surface is well drained, which can quickly dissipate excess pore pressure, then the strength of slip surface will increase and the slip will be slowed down. In addition, if the generated rate of excess pore pressure is faster than the dissipated rate of excess pore pressure, it may cause the creep slip to become a rapid slip.

碩士
國立成功大學
地球科學系
106
The acid mine drainage (AMD) is a severe environmental problem in mining areas, e.g., Chin-Kua-Shih, northern Taiwan, because of its high acidity as well as abundant toxic elements, and sulfate contents. Nonetheless, rare earth elements (REEs), popular raw materials for modern industries, are found enriched in AMD. In this study, we provided two remediation methods to neutralize the water acidity and recover the REEs from the Chin-Kua-Shih AMD system. For one hand, laboratory precipitation experiments using fluidized bed reactor had successfully reduced the heavy metals and REEs concentration of AMD waters by adsorption processes; Meanwhile, the inserted carbonate neutralized the water pH from 2.8 to 5.1. On the other hand, laboratory batch adsorption experiments showed that BT9M (α-FeOOH-εMnO2), a by-product of FBR-fenton, could adsorb the REEs and toxic metals from the AMD waters. The adsorption isotherm model of cerium on BT9M fits well with the Freundlich isotherm model. The Freundlich constant, n 〈 1, and zeta potential of εMnO2 indicated that BT9M performed unfavorable adsorption in acidic solutions. Overall, this study has demonstrated reliable remediation and REEs recovery approaches for the AMD waters, that aims for developments in the future remediation projects.