Este trabalho apresenta os parâmetros de transporte e atenuação dos íons \'K POT.+\', \'CU POT.2+\' e \'CL POT.-\' obtidos em ensaios de coluna, para uma mistura compactada e saturada de solos lateríticos da Formação Botucatu e Serra Geral. As soluções contaminantes percoladas foram cloretos de potássio e de cobre em três diferentes concentrações. Os resultados obtidos estão apresentados na forma de curva de chegada e os parâmetros de transporte e atenuação foram estimados através do ajuste de curvas teóricas aos dados experimentais das colunas. A mistura compactada mostrou-se satisfatória para o uso em barreiras selantes (liner) uma vez que os resultados de condutividade hidráulica e de sorção dos íons estudados são razoáveis. / This paper presents transport and attenuation parameters of \'K POT.+\', \'CU POT.2+\' e \'CL POT.-\', obtained in columns test using a compacted and saturated mixture of two lateritic soils from Botucatu and Serra Geral formation. The contaminant leaching solution was composed of KCl and \'CU\'CL IND.2\'.2\'H IND.2\'O\' with concentrations three different. The results obtained are presented in the form of breakthrough curves and the transport and attenuation parameters estimated through fitting procedures of the theorical curves related to the real column data. The compacted mixture showed to be satisfactory for liner usage since the results of the hydraulic conductivity and the ions sorption in these soils are reasonable.

No description available.

The combination of traditional passive acoustic liners with Herschel-Quincke (HQ) waveguides is proposed in this work as a device for Turbofan Engine Noise Control. The approach consists of installing circumferential arrays of HQ tubes on the lined sector of the inlet of a turbofan engine. A theoretical model is developed to predict the performance of this system assuming that the engine inlet is a circular lined duct with uniform mean flow. The tube-duct interfaces are modeled as finite piston sources that couple the sound field inside the duct with the dynamics of the HQ tubes. The finite piston source radiation is modeled in terms of a new closed form Green's function, which is found as the solution of the non-homogeneous convected acoustic wave equation with soft wall boundary conditions. The Green's function is extended from a point source to a finite piston by using the Divergence Theorem in the appropriate form. The dynamics of the HQ tube are both modeled as plane waves inside a straight tube and experimentally determined. The experimental determination of the HQ-dynamics is undertaken using impedance tubes with a 4-microphone technique. The newly developed theoretical model was used to predict the performance of a combined HQ-Liner system, which was tested on a scale simulated turbofan rig. The model is validated for broadband noise with the experimental data obtained from this test rig. The analytical predictions are shown to correlate well with experimental data. The results of the application of a HQ-Liner on a turbofan engine show a great potential in order to improve the performance of traditional passive acoustic liners. / Ph. D.

The goal of this case study was to investigate the economic feasibility of a new enterprise for Southside Virginia farmers to help alleviate problems stemming from a loss of income and excess production capacity of a tobacco greenhouse. Maple liner production in a tobacco greenhouse was determined to not be economically feasible by this study. The control scenario, as well as the sensitivity analysis revealed that maple liner production would yield a loss when produced in a tobacco greenhouse. The breakeven number of plants to be sold was 43% of the cuttings planted, and could exceed 50% under some conditions of the sensitivity analysis. While the maple liner production schedule was determined to be culturally suitable as a supplemental greenhouse activity, the tobacco greenhouse engineering design was deemed inadequate for maple liner production. Modifications were needed to the ventilation and irrigation systems. This economic study was based on a field trial conducted in Halifax County, Virginia. / Master of Science

This thesis documents trailing edge blowing research performed to reduce rotor / stator interaction noise in turbofan engines. The existing technique of filling every velocity deficit requires a large amount of air and is therefore impractical. The purpose of this research is to investigate new blowing configurations in order to achieve noise reduction with lesser amounts of air. Using the new configurations air is not injected into every fan blade, but is instead varied circumferentially. For example, blowing air may be applied to alternating fan blades. This type of blowing configuration both reduces the amount of air used and changes the spectral shape of the tonal interaction noise. The original tones at the blade passing frequency and its harmonics are reduced and new tones are introduced between them. This change in the tonal spectral shape increases the performance of acoustic liners used in conjunction with trailing edge blowing. This thesis presents numerical predictions performed to estimate the sound power reductions due to these concepts, as well as experimental results taken on the ANCF rig at NASA Glenn for validation purposes. The results show that the new concepts are successful in increasing the efficiency of trailing edge blowing. / Master of Science

Landfill facilities are required to have a barrier system that will limit escape of contaminants to groundwater and surface water for the contaminating lifespan of landfill. Heat generated by the biodegradation of waste and chemical reactions in landfills reduces the service-life of geomembranes by accelerating the ageing process of high-density polyethylene. It may also lead to the desiccation of clay components of the liners. Four considerations with respect to the evaluation of the potential effects of liner temperature on the service-life of liners and the potential control of liner temperature are examined. For the first time, the likely temperature and service-life of a secondary geomembrane in a double composite lining system is predicted. It is shown that, in some cases, the temperature is likely to be high enough to substantially reduce the service-life of the secondary geomembrane. The possible effectiveness of using tire chips as passive thermal insulation between the primary and secondary liners, as well as traditional soil materials, is then explored. For the barrier system and contaminant examined, the results show that tire chips could potentially lower the temperature of the secondary geomembrane sufficiently to significantly extend its service-life. However, the use of tire chips brings about other practical issues, which are also discussed in this study. An active alternative method of controlling the increase in the landfill liner temperature is then examined. This approach, which is inspired by geothermal heat pumps, involves an array of cooling pipes beneath the waste. Numerical modelling showed that the hypotetical introduction of the cooling pipes resulted in a reasonable decrease in liner temperature. It is suggested that the proposed technique warrants further consideration. Finally the conditions that may lead to the desiccation of geosynthetic clay liners used in composite liners due to waste generated heat are examined and recommendations regarding possible means of mitigating the effects of heat on the performance of GCLs are presented. For example, numerical modelling shows that the hydration of GCL prior to waste placement, liner temperature, overburden stress, depth to aquifer and moisture content and grain size of subsoil affect desiccation. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2011-07-31 07:34:33.165

No description available.

Accurate modeling of contaminant transport and sorption processes in the soil and landfill liners is a prerequisite for realistic model simulations of contaminant fate and transport in the environment. These studies are also important for the remediation of soil and groundwater contamination. Modeling of contaminant transport through soils and landfill liners consists of either solving the direct/forward problem or the inverse problem. In this thesis, an automated time-stepping implicit procedure is developed from the convergence and error studies of explicit and implicit finite-difference solutions for the advection-dispersion transport of contaminants through soil with different sorption mechanisms. This study is further extended for transient through-diffusion (TTD) transport of contaminant in landfills by considering linear sorption mechanism. To validate the numerical solution and also to study the behavior of finite-difference numerical solutions for TTD transport problem, closed-form analytical solution is derived. Further, a new interface condition is proposed based on the finite-volume procedure for stratified soil or landfill liner system. Solvers are developed for the parameter estimation of inverse problem by integrating the developed procedures for the above forward problem with different optimization procedures. Solvers based on Simulated Annealing (SA) and Genetic Algorithm (GA) are developed for TTD transport in the landfill liners and verified with the existing methods of parameter estimation. Novel swarm intelligence based solver is developed for the first time for parameter estimation in contaminant transport inverse problem to overcome some of the limitations of the classical optimization methods and evolutionary methods such as GA. Additionally, the proposed swarm intelligence based algorithms and a new variant is applied to solve ill-posed problem of contaminant source characterization. The presented work in this dissertation can be unswervingly applied for modeling the contaminant transport in laboratory through-diffusion tests and contaminant transport through landfill liners where the transport is usually considered to be one-dimensional and also diffusion-dominated. Similarly, the advection-dispersion transport through laboratory soil columns can also be modeled with the developed, fast, automated, implicit numerical procedure with very good accuracy. The present study can be applied further for contaminant transport through stratified soil/liner system using fast converging numerical algorithms. Finally, the problems of design parameter estimation and source characterization can be handled accurately by the use of developed automated nature-inspired solvers.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-08-24T11:49:53Z No. of bitstreams: 1 DANIELA LIMA MACHADO DA SILVA - DISSERTAÇÃO (PPGECA) 2018.pdf: 1711823 bytes, checksum: c48feb8c7f2a334be9eb3ff6467dc92c (MD5) / Made available in DSpace on 2018-08-24T11:49:53Z (GMT). No. of bitstreams: 1 DANIELA LIMA MACHADO DA SILVA - DISSERTAÇÃO (PPGECA) 2018.pdf: 1711823 bytes, checksum: c48feb8c7f2a334be9eb3ff6467dc92c (MD5) Previous issue date: 2018-03-19 / Nos aterros sanitários, a camada de base usada para a impermeabilização deve garantir que não haja migração de poluentes para o meio ambiente, sendo denominada de liner. A avaliação dos mecanismos que regem o transporte de contaminantes nos materiais geológicos pode ser realizada em laboratório por meio de ensaios de equilíbrio em lote, que consiste em uma forma rápida de estimar a adsorção de cátions metálicos pelos solos. O objetivo desse trabalho foi avaliar a adsorção de metais tóxicos em dois liners de solos compactados, com composições diferentes, utilizando os ensaios de equilíbrio em lote. Os solos estudados compreendem ao liner da base de uma célula experimental, que simula um aterro sanitário, e um liner da base de um aterro em escala real, localizado no município de Campina Grande-PB. O liner usada na célula experimental é composta por solo natural compactado, enquanto que no aterro sanitário, foi realizada a adição de bentonita ao solo local, sendo essa mistura, posteriormente, compactada. As amostras de solos do liner da célula experimental foram coletadas em uma jazida localizada no município de Boa Vista-PB, a qual encontra-se situado a 50 km do município de Campina Grande-PB. O solo do liner usado no aterro sanitário, foi coletado na área do próprio aterro, que se localiza em Catolé de Boa Vista, distrito de Campina Grande-PB. As amostras dos respectivos liners foram coletadas, armazenadas no Laboratório de Geotecnia Ambiental, do Departamento de Engenharia Civil da Universidade Federal de Campina Grande, e preparadas para a caracterização geotécnica, físico-química e mineralógica. No ensaio de equilíbrio em lote foram utilizadas soluções com proporção solo-solução 1: 12,5 (4g de solo seco para 50 mL de solução). As isotermas experimentais obtidas foram ajustadas estatisticamente aos modelos físico-químicos de adsorção linear, de Langmuir e Freundlich. Os ajustes das curvas experimentais foram realizados pelo método interativo de Gauss-Newton. A ferramenta utilizada foi o software STATISTICA 8.0, utilizando modelos não-lineares e empregando o método dos mínimos quadrados, considerando como critério o maior coeficiente de determinação (R2). O modelo de Langmuir e de Freundlich se ajustaram melhor às isotermas do solo do liner da célula experimental, enquanto que a adsorção ocorrida no liner do aterro sanitário foi melhor ajustada ao modelo de Langmuir. Os diferentes solos estudados neste trabalho apresentaram propriedades adsortivas para todos os metais, o que o viabiliza para ser empregado em camadas de base de solo compactado para aterros sanitário, além de outras aplicações em geotecnia ambiental. Dentre os metais pesquisados, o chumbo se destacou por apresentar a maior adsorção em relação aos demais metais em ambos os solos. A caracterização geotécnica, físico-química e mineralógica, bem como o comportamento adsortivo dos solos, verificado por meio de ensaio de equilíbrio em lote, indica que os materiais estudados apresentam um relevante potencial para o uso em liners para aterros sanitários. / In sanitary landfills, the base layer used for waterproofing should ensure that there is no migration of pollutants into the environment and is called a liner. The evaluation of the mechanisms governing the transport of contaminants in the geological materials can be carried out in the laboratory by means of equilibrium tests in lot, which consists of a quick way of estimating the adsorption of metallic cations by the soils. The objective of this work was to evaluate the adsorption of toxic metals in two liners of compacted soils, with different compositions, using the equilibrium assays in lot. The studied soils comprise the base liner of an experimental cell, which simulates a sanitary landfill, and a liner from the base of a real-scale landfill, located in the municipality of Campina Grande-PB. The liner used in the experimental cell is composed of compacted natural soil, while in the sanitary landfill, the addition of bentonite was carried out to the local soil, and this mixture was later compacted. Soil samples from the liner of the experimental cell were collected in a field located in the municipality of Boa Vista-PB, which is located at 50 km from the city of Campina Grande-PB. The soil of the liner used in the sanitary landfill was collected in the landfill site, which is located in Catolé de Boa Vista, a district in Campina Grande-PB. The samples of the respective liners were collected, stored in the Laboratory of Environmental Geotechnics, from the Department of Civil Engineering in the Federal University of Campina Grande, and prepared for the geotechnical, physical-chemical and mineralogical characterization. In the equilibrium assay in lot, solutions with 1: 12,5 soil-solution ratio (4g of dry soil for 50 ml solution) were used. The experimental isotherms obtained were statistically adjusted to the physical-chemical models of linear adsorption, Langmuir and Freundlich. The adjustments of the experimental curves to the models were performed using the STATISTICA 8.0 software, applying the nonlinear regression of the least squares method, using the Gauss-Newton algorithm. Considering the R2 ≥ 0.7 criterion, the Langmuir and Freundlich model were better fitted to the liner soil isotherms of the experimental cell, while the adsorption occurred in the liner of the sanitary landfill was better fitted to the Langmuir model. The different soils studied in this work presented adsorptive properties for all metals, which makes it feasible to be used in compacted soil base layers for sanitary landfills, as well as other applications in environmental geotechnics. Among the metals studied, the Pb was distinguished by the higher adsorption in relation to the other metals in both soils. The geotechnical, physical-chemical and mineralogical characterization, as well as the adsorptive behavior of the soils, verified by means of a balance test in lot, indicates that the studied materials present a relevant potential for the use in liners for sanitary landfills.

La réduction des nuisances sonores induites par les aéronefs civils autour des grands aéroports est devenue un enjeu sociétal important. Pour réduire le bruit propulsif de soufflante, devenu prépondérant au cours des dernières années avec l'avènement de turboréacteurs à double flux, les constructeurs sont amenés à généraliser l'utilisation de matériaux absorbants acoustiques (également appelés « liners »). Ce sujet de thèse s'inscrit dans le cadre de l'amélioration des outils CAA relativement à la prévision numérique de ces matériaux absorbants. Cette modélisation soulève plusieurs interrogations, liées à divers aspects tels que le type d'écoulement mis en jeu (inhomogénéités, couche limite, etc.), les niveaux acoustiques en présence (effets de non linéarité), les effets de diffraction induits par les ruptures d'impédance, etc. Cette étude consiste donc à valider et à améliorer la condition limite d'impédance, implémentée dans le solveur CAA sAbrinA.v0, développé par l'Onera. Des développements théoriques sont d'abord consacrés à la modélisation de l'impédance dans le domaine temporel, et conduisent à une discussion sur la généralisation de cette modélisation. Le travail consiste ensuite à simuler plusieurs cas tests canoniques de l'absorption du bruit par un revêtement acoustique, lesquels sont validés par confrontation avec d'autres résultats analytiques et/ou expérimentaux. Ce travail fournit de nouvelles connaissances sur la façon dont les matériaux absorbants acoustiques peuvent être modélisés et simulés de manière précise dans le cadre d'une approche CAA dans le domaine temporel. / The reduction of acoustic emission induced by civil aircraft around major airports has become an important societal issue. To reduce the fan noise, induced by the engines, which has become preponderant over the past years with the advent of turbofan engines, manufacturers are led to generalize the employment of acoustic absorbing materials (or acoustic “liners”). The present thesis is related to the numerical prediction of such absorbing materials, in the context of time-domain CAA (Computational AeroAcoustics) methods. Such modeling raises several key questions, which are related to various aspects such as the type of flow involved (boundary layers effects, etc.), the sound levels considered (non-linear phenomena), the diffraction effects induced by ruptures of impedance, etc. The present study then consists in validating and improving the time-domain impedance boundary condition implemented in Onera’s structured CAA solver (named sAbrinA.v0). Theoretical developments are first devoted to the modeling of impedance in the time-domain, and lead to a discussion on the generalization of this modeling. The work then consists in CAA-simulating several canonical tests of noise absorption by acoustic liners. Outputs are compared against experimental and/or analytical results, delivering new insight in the way noise absorption materials can be accurately modeled and simulated using time-domain CAA-approaches.