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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Investigation of CO2 Tracer Gas-Based Calibration of Multi-Zone Airflow Models

January 2011 (has links)
abstract: The modeling and simulation of airflow dynamics in buildings has many applications including indoor air quality and ventilation analysis, contaminant dispersion prediction, and the calculation of personal occupant exposure. Multi-zone airflow model software programs provide such capabilities in a manner that is practical for whole building analysis. This research addresses the need for calibration methodologies to improve the prediction accuracy of multi-zone software programs. Of particular interest is accurate modeling of airflow dynamics in response to extraordinary events, i.e. chemical and biological attacks. This research developed and explored a candidate calibration methodology which utilizes tracer gas (e.g., CO2) data. A key concept behind this research was that calibration of airflow models is a highly over-parameterized problem and that some form of model reduction is imperative. Model reduction was achieved by proposing the concept of macro-zones, i.e. groups of rooms that can be combined into one zone for the purposes of predicting or studying dynamic airflow behavior under different types of stimuli. The proposed calibration methodology consists of five steps: (i) develop a "somewhat" realistic or partially calibrated multi-zone model of a building so that the subsequent steps yield meaningful results, (ii) perform an airflow-based sensitivity analysis to determine influential system drivers, (iii) perform a tracer gas-based sensitivity analysis to identify macro-zones for model reduction, (iv) release CO2 in the building and measure tracer gas concentrations in at least one room within each macro-zone (some replication in other rooms is highly desirable) and use these measurements to further calibrate aggregate flow parameters of macro-zone flow elements so as to improve the model fit, and (v) evaluate model adequacy of the updated model based on some metric. The proposed methodology was first evaluated with a synthetic building and subsequently refined using actual measured airflows and CO2 concentrations for a real building. The airflow dynamics of the buildings analyzed were found to be dominated by the HVAC system. In such buildings, rectifying differences between measured and predicted tracer gas behavior should focus on factors impacting room air change rates first and flow parameter assumptions between zones second. / Dissertation/Thesis / M.S. Built Environment 2011
122

Fotodegradação do contaminante emergente 2-(tiocianometiltio) benzotiazol (TCMTB) por meio de fotólise direta

Bertoldi, Crislaine Fabiana January 2017 (has links)
Os contaminantes emergentes são considerados compostos onipresentes em águas, portanto investigar a degradação e comportamento dessas substâncias torna-se necessária, pois é reportado que estes compostos causam efeitos adversos em seres vivos. O composto 2-(tiocianometiltio) benzotiazol (TCMTB), considerado um contaminante emergente, é amplamente empregado na indústria do couro como biocida com a finalidade de inibir o desenvolvimento de microrganismos na pele. Sendo assim, o objetivo do presente trabalho foi estudar a degradação do contaminante emergente TCMTB, por meio das técnicas de fotólise direta com radiação UV, radiação solar e oxidação com ozônio. Experimentos de fotólise direta do TCMTB, em soluções aquosas com diferentes concentrações, em efluente do processo de remolho e efluente simulado do remolho, foram conduzidos em reator com lâmpada de vapor de mercúrio (250 W). O teste de hidrólise foi realizado protegido da luz, a temperatura ambiente com diferentes concentrações do TCMTB para observar o comportamento do contaminante na ausência de luz. O maior coeficiente de absorção molar foi medido e identificado em 220 e 280 nm como 20489 e 11317 M-1 cm-1, respectivamente, para pH 5,0. Os resultados experimentais da fotodegradação mostraram que TCMTB foi rapidamente degradado por fotólise direta em soluções aquosas em 30 min de tratamento fotolítico. Os resultados do estudo do pH, demonstraram que pH interfere no processo fotoquímico, uma vez que em condições alcalinas o composto é mais estável e a taxa de fotodegradação diminui. Os ensaios com o efluente do processo de remolho mostraram que a degradação do TCMTB tem comportamento semelhante às soluções aquosas. O efluente simulado do remolho mostrou que uma alta concentração do contaminante leva a um maior tempo de irradiação de luz para a degradação. A aplicação de luz natural evidenciou degradação mais lenta, mas ainda assim, foi possível observar degradação de até 96% para a concentração de 6 mg L-1 em 420 min. A utilização do oxidante ozônio como tratamento, alcançou 40% de remoção do contaminante em 30 min, assinalando a alta estabilidade do composto. Portanto, este trabalho aponta o potencial do uso de fotólise direta (luz v artificial), ou radiação solar (luz natural) para a degradação de contaminantes emergentes como o 2 (tiocianometiltio) benzotiazol (TCMTB). / Emerging contaminants are considered omnipresent compounds in water, thus investigate the degradation and behavior of these substances becomes necessary as it is reported that these compounds cause adverse effects on living beings. The 2- (thiocyanomethylthio) benzothiazole compound (TCMTB), considered an emerging contaminant, is widely used in the leather industry as a microbicide for the purpose of inhibiting the development of microorganisms in the skin and leather. In this context, the purpose of the present work was to study the degradation of the emerging contaminant TCMTB by direct photolysis with UV radiation, solar radiation and ozone. Experiments of direct photolysis of the TCMTB in aqueous solutions with different concentrations, in the effluent from the soaking process were conducted in a reactor with mercury vapor lamp (250 W). The hydrolysis test was performed protected from light at room temperature with different concentrations of TCMTB to observe the behavior of the contaminant in the absence of light. The highest molar absorption coefficient was measured and identified at 220 and 280 nm as 20489 and 11317 M-1 cm -1, respectively, at pH 5.0. The experimental results of photodegradation showed that TCMTB was rapidly degraded by direct photolysis in aqueous solutions in 30 min of photolytic treatment. The results of the pH study showed that pH interfered in the photochemical process, since under alkaline conditions the compound is more stable and the photodegradation rate decreases. Assays of the direct photolysis in effluent from the soaking process have shown that TCMTB degradation behaves similarly to aqueous solutions. The direct photolysis of the the simulated effluent from the soaking showed that a high concentration of the contaminant leads to a longer time of light irradiation for degradation. The application of natural light evidenced slower degradation, however, it was possible to observe degradation of up to 96% for the 6 mg L-1 concentration with 420 min. The use of the ozone oxidant as a treatment, achieved 40% removal of the contaminant for 30 min of treatment, indicating the high stability of the compound. Therefore, this work highlights the potential of the use of direct photolysis (artificial light), or solar radiation (natural light) for the vii degradation of emerging contaminants such as 2 (thiocyanomethylthio) benzothiazole (TCMTB).
123

Proposta de uma nova função de autocorrelação para o estudo do meandro do vento horizontal / Proposal of a new autocorrelation function in low wind speed conditions

Moor, Lilian Piecha 07 June 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this study is propose a new mathematical expression to describe the observed meandering autocorrelation functions in low-wind speed. The analysis utilizes a large number of the data to show that the new proposed theoretical function reproduces the experimental behavior of the fit curves, well as the negative lobes that characterizing the autocorrelation function for meandering condition. Furthermore, the good agreement of the measured autocorrelation curves with the proposed algebraic autocorrelation function allows to calculate the magnitudes of the meandering period and of the loop parameter. In adition, the parameters founded in this study can be used to simulate the dispersion of contaminant during low wind episodes. The results agree with the values presented and discussed in the literature. / O presente estudo propõe uma nova expressão matemática para descrever as funções de autocorrelação observadas sob condições de meandro do vento horizontal. A análise utiliza um grande número de dados para demonstrar que a função proposta reproduz o comportamento da curva experimental, bem como os lóbulos negativo que caracterizam a função de autocorrelação para a situação de meandro. Além disso, a boa concordância entre as curvas de autocorrelação observadas e a nova função de autocorrelação algébrica, proposta neste trabalho, permitiu realizar o cálculo de grandezas físicas como o parâmetro de oscilação e o período de meandro. Um resultado adicional, foi empregar os valores médios encontrados para os parâmetros do meandro na simulação da dispersão de contaminante durante episódios de vento fraco. Os resultados encontrados estão de acordo com os valores apresentados e discutidos na literatura.
124

Long term chemical and ecological recovery of Kinghorn Loch (Scotland, UK) following red mud pollution

Olszewska, Justyna Paulina January 2016 (has links)
The estimated global production of red mud, a by-product of alumina production, is ~120 million t per year. Little is known about the long-term chemical, physical and ecological responses in aquatic ecosystems following pollution with red mud. To date, no whole-lake assessment of the impact of red mud and recovery trajectories has been conducted. Kinghorn Loch, Fife, Scotland, is an important example of a red mud polluted aquatic ecosystem. This is due mainly to the availability of long-term data documenting changes in the lake during the pollution and recovery following diversion of red mud leachate in 1983 to date. Long-term data were assessed to determine the time scale of recovery for a range of specific pollutants in the surface waters of Kinghorn Loch, and field surveys and a laboratory controlled experiment were conducted to investigate lake sediment-pollutant interactions and arsenic (As) species bioaccumulation in aquatic plants. Results showed recovery of the lake water column, with a significant decrease of pH and the concentrations of all red mud constituents in surface water since the cessation of pollution. Using generalised additive models the chemical recovery period was 5 years for pH and from 22 to 26 years for As, vanadium (V) and phosphorus (P), with aluminium (Al) still not reaching the end-point recovery following this period. A 12- month field survey showed that concentrations of phosphate (PO4-P), total phosphorus (TP), dissolved and total As and V in lake water varied significantly throughout the year, with depth of overlying water contributing to variation in P concentrations in water above sediment. A range of physico-chemical factors, including dissolved oxygen (DO), pH and concentrations of pollutant binding element controlled seasonal and spatial variations in water column contaminant concentrations. The behaviour of V differed from As and P concentrations in water, with maximum V concentrations occurring in spring and the highest concentrations of As and P in surface water and dissolved As and PO4-P in water above sediment observed in summer. With the exception of V in deeper layers of the water column in spring and winter, observed total As and V concentrations met standards for Protection of Aquatic Life in the UK (50 and 20 μg L-1, respectively). Sediment in Kinghorn Loch is still contaminated 30 years into the lake recovery period. The highest seasonal mean concentrations in the upper (0-4 cm) sediment layer were 231 mg kg-1 for V and 185 mg kg-1 for As, the latter considerably exceeding Canadian Sediment Quality Guidelines for the Protection of Aquatic Life for As (17 mg kg-1). Evidence from the laboratory experiment and the field observations suggests that the lake still processes red mud contaminants, with seasonal mobilisation of As and P from lake sediment under reducing conditions. In contrast, release of V from sediment into overlying water appeared not to be driven predominantly by redox conditions, but instead by interactions between pH, competitive ion concentrations and DO. Higher pollutant concentrations observed throughout the year in deeper layers of the water column compared to surface water indicated that the impact of sediment on the water column is generally confined to the bottom waters of the lake. Macrophytes in Kinghorn Loch contained relatively high concentrations of As, predominantly in the inorganic form which is most toxic to organisms. The highest As content measured in roots of Persicaria amphibia (L.) Gray (40.4 – 218 mg kg-1) greatly exceeded the 3 – 10 mg kg-1 range suggested as a potential phytotoxic level. Accumulation of toxic As species by plants suggested toxicological risk to higher organisms in the food web and indicated that ecological recovery of the lake is still in progress. The results of this research at Kinghorn Loch will help water resource managers to understand not only the environmental and human health effects of multiple pressures related to red mud pollution, but also the likely recovery time scales in relation to water quality targets.
125

Revisiter l'alimentation durable en précisant la place de la nutrition et le rôle des produits animaux / Revisiting sustainable diets by specifying the place of nutrition and the role of animal products

Barré, Tangui 06 December 2016 (has links)
L’alimentation durable est respectueuse de l’environnement, culturellement acceptable, financièrement abordable, saine et nutritionnellement adéquate. Le doctorant étudiera la compatibilité entre ces différentes dimensions, en mettant en œuvre des techniques d’épidémiologie nutritionnelle et de modélisation de rations. En particulier, il étudiera sous quelles conditions un ré-équilibrage entre les consommations de produits végétaux et de produits animaux pourrait contribuer à une alimentation durable, au niveau d’une population, et pour des individus. / Sustainable diets are "protective and respectful of biodiversity and ecosystems, culturally acceptable, accessible,economically fair and affordable; nutritionally adequate, safe and healthy; while optimizing natural and human resources". The PhD student will study the compatibility between those different dimensions of sustainability, using nutritional epidemiology and diet modelling. Particularly, he will study the conditions under which re-balancing animal and plant-based food intakes would contribute to more sustainable diets, at individual and population levels.
126

Fotodegradação do contaminante emergente 2-(tiocianometiltio) benzotiazol (TCMTB) por meio de fotólise direta

Bertoldi, Crislaine Fabiana January 2017 (has links)
Os contaminantes emergentes são considerados compostos onipresentes em águas, portanto investigar a degradação e comportamento dessas substâncias torna-se necessária, pois é reportado que estes compostos causam efeitos adversos em seres vivos. O composto 2-(tiocianometiltio) benzotiazol (TCMTB), considerado um contaminante emergente, é amplamente empregado na indústria do couro como biocida com a finalidade de inibir o desenvolvimento de microrganismos na pele. Sendo assim, o objetivo do presente trabalho foi estudar a degradação do contaminante emergente TCMTB, por meio das técnicas de fotólise direta com radiação UV, radiação solar e oxidação com ozônio. Experimentos de fotólise direta do TCMTB, em soluções aquosas com diferentes concentrações, em efluente do processo de remolho e efluente simulado do remolho, foram conduzidos em reator com lâmpada de vapor de mercúrio (250 W). O teste de hidrólise foi realizado protegido da luz, a temperatura ambiente com diferentes concentrações do TCMTB para observar o comportamento do contaminante na ausência de luz. O maior coeficiente de absorção molar foi medido e identificado em 220 e 280 nm como 20489 e 11317 M-1 cm-1, respectivamente, para pH 5,0. Os resultados experimentais da fotodegradação mostraram que TCMTB foi rapidamente degradado por fotólise direta em soluções aquosas em 30 min de tratamento fotolítico. Os resultados do estudo do pH, demonstraram que pH interfere no processo fotoquímico, uma vez que em condições alcalinas o composto é mais estável e a taxa de fotodegradação diminui. Os ensaios com o efluente do processo de remolho mostraram que a degradação do TCMTB tem comportamento semelhante às soluções aquosas. O efluente simulado do remolho mostrou que uma alta concentração do contaminante leva a um maior tempo de irradiação de luz para a degradação. A aplicação de luz natural evidenciou degradação mais lenta, mas ainda assim, foi possível observar degradação de até 96% para a concentração de 6 mg L-1 em 420 min. A utilização do oxidante ozônio como tratamento, alcançou 40% de remoção do contaminante em 30 min, assinalando a alta estabilidade do composto. Portanto, este trabalho aponta o potencial do uso de fotólise direta (luz v artificial), ou radiação solar (luz natural) para a degradação de contaminantes emergentes como o 2 (tiocianometiltio) benzotiazol (TCMTB). / Emerging contaminants are considered omnipresent compounds in water, thus investigate the degradation and behavior of these substances becomes necessary as it is reported that these compounds cause adverse effects on living beings. The 2- (thiocyanomethylthio) benzothiazole compound (TCMTB), considered an emerging contaminant, is widely used in the leather industry as a microbicide for the purpose of inhibiting the development of microorganisms in the skin and leather. In this context, the purpose of the present work was to study the degradation of the emerging contaminant TCMTB by direct photolysis with UV radiation, solar radiation and ozone. Experiments of direct photolysis of the TCMTB in aqueous solutions with different concentrations, in the effluent from the soaking process were conducted in a reactor with mercury vapor lamp (250 W). The hydrolysis test was performed protected from light at room temperature with different concentrations of TCMTB to observe the behavior of the contaminant in the absence of light. The highest molar absorption coefficient was measured and identified at 220 and 280 nm as 20489 and 11317 M-1 cm -1, respectively, at pH 5.0. The experimental results of photodegradation showed that TCMTB was rapidly degraded by direct photolysis in aqueous solutions in 30 min of photolytic treatment. The results of the pH study showed that pH interfered in the photochemical process, since under alkaline conditions the compound is more stable and the photodegradation rate decreases. Assays of the direct photolysis in effluent from the soaking process have shown that TCMTB degradation behaves similarly to aqueous solutions. The direct photolysis of the the simulated effluent from the soaking showed that a high concentration of the contaminant leads to a longer time of light irradiation for degradation. The application of natural light evidenced slower degradation, however, it was possible to observe degradation of up to 96% for the 6 mg L-1 concentration with 420 min. The use of the ozone oxidant as a treatment, achieved 40% removal of the contaminant for 30 min of treatment, indicating the high stability of the compound. Therefore, this work highlights the potential of the use of direct photolysis (artificial light), or solar radiation (natural light) for the vii degradation of emerging contaminants such as 2 (thiocyanomethylthio) benzothiazole (TCMTB).
127

Hromadná dekontaminace osob v konkrétním vybraném stacionárním objektu provedená improvizovaným způsobem. / Mass extemporaneous decontamination of people in concrete stationary object.

LEVÝ, Leoš January 2010 (has links)
This thesis consists of three main parts. In the first part, the general procedures and principles of decontamination, the decontamination substances and mixtures, as well as the technique that is used for decontamination, have been described. Next, the description of the decontamination of the first responders, as this part of the decontamination process has been given; it has been elaborated and checked in practice. In the second part, there is the drafted plan of the mass extemporaneous decontamination of people in the selected public facility, according to the general methods of decontamination. Next, there is the drafted documentation for resolving an extraordinary event: an accident with subsequent leakage of a dangerous chemical substance, resulting in the need to carry out the mass decontamination of people in selected public facilities. In the last part, I have discussed and compared the advantages and possible disadvantages of the selected object of for the implementation of mass decontamination of people. There is also a suggested way of how to carry out this decontamination in this object in the most efficient way. The processing of this documentation has clearly confirmed my hypothesis. The mass decontamination of people in the selected location, in this case specifically in the Domazlice Hostel and Swimming Pool, can be feasibly performed with an improvised method. After giving the specific supplemented data (the names of the personnel, the telephone numbers, places of storage material etc.), the suggested documentation is usable for the object in practice. The documentation can be also easily adapted to other similar public facilities.
128

Föroreningstransport i grundvatten : En modelljämförelse / Contaminant transport in groundwater : A comparison of models

Ekman, Caroline January 2004 (has links)
This thesis compares different methods for risk assessment of a creosote contaminated site in Vansbro, Dalarna. In a complementary study the importance of using representative data for calibration and validation of stationary groundwater models is discussed. The time dependency between surface water levels and groundwater levels on the site in Vansbro is evaluated by step response analysis. The results show that the groundwater levels reflect only long-term variation in the surface water levels. Hence the use of such long-term means for calibration and validation of the stationary groundwater models is the only theoretically defendable alternative. As a first step in the comparison of risk assessment methods the degree of contamination is evaluated on the basis of generic guideline values for contaminated soils, developed by the Swedish Environmental Protection Agency. The guidelines specifically developed for contaminated petrol stations are also taken into consideration. Secondly, a site-specific evaluation is carried out. The transport of contaminants from the soil to the on-site groundwater and nearby surface water is calculated using the mathematical models behind the aforementioned guideline values. The calculated groundwater concentrations show a poor agreement with observed data and the thesis points out several possible explanations of this deviation. A sensitivity analysis is carried out and the influence of biodegradation during the transport in the aquifer is evaluated. The results indicate that the deviation between observed and calculated groundwater concentrations cannot be explained by the absence of biodegradation in the mathematical models, but rather by other simplifications and uncertainties in estimated model parameters. Finally, a risk assessment is made on the basis of observed groundwater concentrations instead of observed soil concentrations as in the assessments above. Observed groundwater concentrations are compared with guideline values for groundwater on contaminated sites. The risk of negative environmental effects in the surface water is evaluated based on the estimated inflow of contaminated groundwater and its concentration of contaminants. The inflow is estimated from the interpolation of observed groundwater levels as well as with two numerical groundwater models of varying hydrogeological complexity: a three-dimensional flow model developed in Visual MODFLOW and a two-dimensional flow model developed in TWODAN. The models are compared with respect to the calculated inflows of contaminated groundwater into the surface water body as well as their ability to reproduce observed groundwater levels. The results indicate that the differences between the models, with respect to the calculated inflows, are of lesser importance to the risk assessment in comparison with the uncertainties associated with other parameters. The choice to base the assessment on observed contaminant concentrations in either the soil or the groundwater is shown to be of crucial importance. / I detta examensarbete jämförs olika metoder att bedöma de hälsomässiga och miljömässiga risker som föreligger med ett kreosotförorenat markområde i Vansbro, Dalarna. I en kompletterande undersökning belyses vikten av att stationära grundvattenmodeller kalibreras och valideras mot tidskompatibla indata. Tidsberoendet mellan yt- och grundvattennivåer på området i Vansbro studeras genom stegsvarsanalys. Resultaten visar att grundvattennivåerna på området anpassar sig mycket långsamt efter rådande ytvattennivåer. Grundvattennivåerna återspeglar således medelvärden av ytvattennivåerna över en mycket lång tidsperiod. Därför är användandet av sådana medelvärden för kalibrering och validering av modellerna det enda teoretiskt försvarbara alternativet. Som ett första steg i jämförelsen mellan olika riskbedömningsmetoder utvärderas föroreningssituationen baserat på uppmätta föroreningskoncentrationer i jorden och med hjälp av Naturvårdsverkets generella samt branschspecifika riktvärden för förorenad mark. Därefter genomförs en platsspecifik riskbedömning. Föroreningstransporten från markområdet till grundvattnet samt till ett närbeläget ytvatten beräknas med de matematiska modeller som användes av Naturvårdsverket vid framtagandet av ovannämnda riktvärden. Beräknade grundvattenkoncentrationer jämförs med uppmätta koncentrationer och resultaten visar på stora avvikelser. En känslighetsanalys utförs och inverkan av biologisk nedbrytning i akviferen utvärderas. Resultaten tyder på att avvikelsen mellan uppmätta och beräknade grundvattenkoncentrationer ej förklaras av att biologisk nedbrytning inte beaktas i modellerna utan att avvikelsen härrör från andra förenklingar och från osäkerheter i indata. Slutligen genomförs en platsspecifik riskbedömning, motsvarande den ovan, men denna gång utifrån uppmätta föroreningskoncentrationer i grundvattnet. De uppmätta grundvattenkoncentrationerna jämförs direkt mot Naturvårdsverkets riktvärden för grundvatten på förorenade områden. Risken för negativa ekologiska effekter i ytvattnet utvärderas utifrån det beräknade inflödet av förorenat grundvatten samt dess koncentration. Inflödet beräknas överslagsmässigt utifrån interpolerade grundvattennivåer samt med två numeriska grundvattenmodeller av olika hydrogeologisk komplexitet: en tredimensionell flödesmodell uppbyggd i Visual MODFLOW och en tvådimensionell modell uppbyggd i TWODAN. Grundvattenmodellerna jämförs med avseende på det beräknade inflödet och med avseende på deras förmåga att beskriva observerade grundvattenförhållanden.Resultaten tyder på att skillnaden i det, med de olika metoderna, beräknade inflödet är av liten betydelse för riskbedömningen i förhållande till osäkerheter förknippade med övriga parametrar. Störst betydelse för riskbedömningen får valet att utgå från uppmätta föroreningskoncentrationer i antingen jorden eller grundvattnet.
129

Avaliação do comportamento de uma mistura compactada de solos lateríticos frente a soluções de Cu++, K+ e Cl- em colunas de percolação / not available

Fernando Eduardo Boff 20 July 1999 (has links)
Mistura compactada de materiais inconsolidados das formações Serra Geral e Botucatu foram percoladas por soluções com diversas concentrações de K+, Cl- e Cu++, em testes de coluna, para a avaliar a potencialidade da sua utilização como liner. Na modelagem dos resultados adotaram-se resoluções analíticas e semi-analíticas (programa POLLUTE v6). Estudo complementar sobre o comportamento eletroquímico destes solos foi realizado pelos ensaios de titulação potenciométrica, capacidade de tamponamento, pH em água e KCI, CTC e análise mineralógica por difração de Raios-X e térmica diferencial. Os resultados mostraram uma forte influência das características da carga elétrica superficial do solo no comportamento competitivo dos íons. / A compacted mixture of soils from Serra Geral and Botucatu formations were percolated by chemical solutions with several concentrations of K+, Cu++ e Cl-, in column tests, in order to assess the potential of this mixture as a liner-building material. In the modeling procedures for the results, analytical and semi-analytical solutions (POLLUTE v.6 software) were used. Additional studies about the electrochemical behavior of these soils were performed, using potenciometric titration, soil buffer capacity, pH in water and KCI and mineralogical assessment by X-Ray Diffraction and differential thermal analysis. The results showed a very strong influence of the soil superficial charge in the competitive ion behavior.
130

Algoritmos evolucionÃrios multipopulaÃÃo na otimizaÃÃo multiobjetiva da remediaÃÃo de Ãguas subterrÃneas / Multi-population Evolutionary Algorithm Multi-Objective Optimization of Groundwater Remediation

Marcos Rodrigues Pinto 24 July 2009 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Ao longo das Ãltimas trÃs dÃcadas os algoritmos evolucionÃrios vÃm sendo aplicados com sucesso nas mais diversas Ãreas. Dentre as principais vantagens dos algoritmos evolucionÃrios estÃo a facilidade de aplicaÃÃo, a eficiÃncia e a confiabilidade. Na remediaÃÃo de Ãguas subterrÃneas, geralmente, os objetivos sÃo minimizar custos, minimizar a presenÃa do contaminante, maximizar a eficiÃncia do bombeamento, entre outros. Esses objetivos sÃo naturalmente conflitantes e a busca de soluÃÃes Ãtimas, ou quase Ãtimas, faz-se necessÃria. Tendo em vista esse fato, os mÃtodos de otimizaÃÃo evolucionÃria vÃm sendo aplicados e aperfeiÃoados na busca dessas soluÃÃes. à apresentada uma breve descriÃÃo de alguns desses mÃtodos, discutindo-se algumas de suas vantagens e limitaÃÃes. Cinco funÃÃes matemÃticas sÃo utilizadas para avaliar o desempenho dos algoritmos e tambÃm para servir de base para efetuar uma comparaÃÃo entre os mesmos. Para otimizar um sistema âbombear-e-tratarâ na remediaÃÃo de um sÃtio hipotÃtico, sÃo utilizados algoritmos evolucionÃrios multipopulaÃÃo, tratando o problema na sua dimensÃo multiobjetiva. A abordagem multipopulaÃÃo vem sendo empregada como mitigadora de um dos principais inconvenientes da otimizaÃÃo evolucionÃria: o excessivo tempo computacional. O fluxo de Ãguas subterrÃneas à modelado com o MODFLOW (modular finite-difference flow model), enquanto o transporte de contaminante à simulado com o MT3DMS (modular three-dimensional multispecies transport model). SÃo propostos dois algoritmos multipopulaÃÃo: MINPGA (Multi-Island Niched Pareto Genetic Algorithm), a partir do NPGA (Niched Pareto Genetic Algorithm) e da abordagem de ilhas de injeÃÃo; MHBMO (Multiple Hive Honey Bee Mating Optimization), uma versÃo multipopulaÃÃo do HBMO (Honey Bee Mating Optimization). TambÃm à utilizada uma versÃo multipopulaÃÃo do PSO (Particle Swarm Optimization), chamada MCPSO (Multi-Swarm Cooperative Particle Swarm Optimization). Os testes com funÃÃes matemÃticas validaram os algoritmos apresentados, e o problema de otimizaÃÃo do sistema âbombear-e-tratarâ tem como objetivos a minimizaÃÃo do custo da remediaÃÃo e da quantidade final da pluma contaminante. Todos os algoritmos obtiveram bons resultados, com sutil vantagem para o MINPGA / Through the last three decades the evolutionary algorithms have been successful on application to many areas. Easily applied, efficiency and confidence are the main advantages of the evolutionary algorithms. In the groundwater remediation, generally, the objectives are the cost minimization, minimization of contaminant presence, maximization of pumping efficiency, among others. These objectives are naturally in conflicting and the search for optimal solutions, or almost optimal solutions are needed. In view of that, the evolutionary optimization methods have been applied and refined in order to search these solutions. A brief description of these methods is presented, referring to their advantages and limitations. Five mathematical functions are used to measure the algorithms performance and allow a comparison between them. In order to optimize a âpump-and-treatâ system in the remediation of a hypothetical site, multi-population evolutionary algorithms are used, considering the problem multi-objective dimension. The multi-population approach has been applied as mitigate for the main evolutionary optimization drawback: the excessive computational time. The groundwater flow modeler MODFLOW (modular finite-difference flow model) is used with the contaminant transport simulator MT3DMS (modular three-dimensional multispecies transport model). Two multi-population algorithms are presented: MINPGA (Multi-Island Niched Pareto Genetic Algorithm), that is a NPGA (Niched Pareto Genetic Algorithm) multi-population version with the injection island approach; MHBMO (Multi-Hive Honey Bee Mating Optimization), that is a HBMO (Honey Bee Mating Optimization) multi-population version. A PSO (Particle Swarm Optimization) multi-population version, called MCPSO (Multi-Swarm Cooperative Particle Swarm Optimization) is too used. Tests with mathematical functions validate the presented algorithms. Remediation problem using the âpumping-and-treatâ technique had as objectives the minimization of remediation cost and minimization of contaminant final plume. The results were shown to be very good for all algorithms, but MINPGA had a tenuous advantage over others

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