Permeable reactive barrier (PRB) technology is increasingly considered for in situ treatment of contaminated groundwater; however, current design formulas for PRBs are limited and do not properly account for all major physical and attenuation processes driving remediation. This study focused on developing a simple methodology to design PRBs that is easy to implement while improving accuracy and being more conservative than the available design methodologies. An empirical design equation and a simple analytical design equation were obtained to calculate the thickness of a PRB capable of degrading a contaminant from a source contaminant concentration to a maximum contaminant level at a Point of compliance . Both equations integrate the fundamental components that drive the natural attenuation process of the aquifer and the reactive capacity of the PRB.The empirical design equation was derived from a dataset of random hypothetical cases that used the solutions of the PRB conceptual model (Solution I). The analytical design equation was derived from particular solutions of the model (Solution II) which the study showed fit the complex solutions of the model well. Using the hypothetical cases, the analytical equation has shown that it gives an estimated thickness of the PRB just 15 % lower or higher than the real thickness of the PRB 95 percent of the time. To calculate the design thickness of a PRB, Natural attenuation capacity of the aquifer can be estimated from the observed contaminant concentration changes along aquifer flowpaths prior to the installation of a PRB. Bench-scale or pilot testing can provide good estimates of the required residence times ( Gavaskar et al. 2000) , which will provide the reactive capacity of the PRB needed for the calculation. The results of this study suggest also that the installation location downgradient from the source of contaminant is flexible. If a PRB is installed in two different locations, it will achieve the same remediation goals. This important finding gives engineers and scientists the choice to adjust the location of their PRBs so that the overall project can be the most feasible and cost effective. / Master of Science

Thesis advisor: John E. Ebel / This research describes a method to carry out quantitative analyses of sub-seabed sediments using high-resolution chirp seismic profiles in order to estimate the properties of subsurface sediments. The method identifies significant sedimentary interfaces, extracts them from the seismic record, and measures the inelastic attenuation coefficients (k) of the sedimentary layers. The k values and their variations with increasing depth of sediments are indicative of the amount of compaction of the sediment. The k values are correlated with borehole lithology to provide a relationship between k measurements and local borehole lithology. Once determined for an area, the correlation can be applied to other seismic records from the area to analyze sedimentary properties even if no borehole lithology is locally available. / Thesis (MS) — Boston College, 2016. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

Estudos recentes constataram a existência de processos que permitem a atenuação natural dos contaminantes presentes nos lixiviados. O adequado entendimento destes processos pode originar benefícios possíveis de serem aplicados em aterros antigos, novos ou naqueles que ainda serão concebidos. O presente estudo avaliou o comportamento e a atenuação de contaminantes dos líxiviados no solo, por meio de experimento desenvolvido em colunas de percolação e, para a avaliação da atenuação este teste é indicado por refletir as condições naturais e as características adsortivas do solo, propiciando uma melhor simulação da atenuação. O lixiviado e o solo utilizados neste experimento são provenientes do aterro sanitário de São Carlos - SP. O solo utilizado foi caracterizado quanto à composição física, química, biológica e mineralógica para verificar o transporte do percolado nas colunas e a interação solo-contaminante. Na área do aterro foram feitas perfurações, ensaios de condutividade hidráulica e avaliação da geologia local, para conhecimento das características físicas, químicas, biológicas, mineralógicas e geológicas do solo in situ. Este foi classificado como arenoso, apresentando características físicas e químicas que não se enquadram nos parâmetros adequados para sua utilização em áreas de disposição de resíduos sólidos urbanos, pois, a capacidade de troca de cátions, superfície específica, potencial hidrogeniônico e classe textural arenosa, evidenciam que este solo possui deficiente capacidade de retenção e imobilização de contaminantes. Além disso, pela observação in situ, constata-se que a área de disposição de resíduos sólidos de São Carlos esta situado sobre rochas da Formação Botucatu, sendo que a mineralogia do solo presente no local é composta de quartzo, caulinita, goethita, hematita, gibsita e ilita. O ensaio de condutividade hidráulica indicou que o solo presente na base do Aterro sanitário não atende a valor de permeabilidade exigida por norma, o que poderá permitir a infiltração de água da chuva, aumentando a produção do lixiviado e sua movimentação no perfil, podendo atingir as águas subterrâneas. Assim, foram traçadas curvas características do transporte de contaminantes nas amostras efluentes monitoradas durante o processo de percolação, coletadas a cada 0,25 volume de poros até atingir 10,0 volume de poros percolados. As curvas características do transporte de contaminantes traçadas apresentaram baixas concentrações de Chumbo, Cádmio, Ferro, Zinco, Manganês, Cálcio, Magnésio, Cobre, Cromo nas amostras fluentes. Já o Sódio, Potássio, Cloro, Níquel e Alumínio foram preferencialmente percolados com o lixiviado, evidenciando a variação da faixa de concentração de cada elemento no percolado. Os perfis de concentração dos metais pesados mostraram que existe uma frente de contaminação. As curvas de retenção de metais no solo mostraram que a preferência de sorção apresentada pelos solos nas colunas foi : Cobre > Cádmio > Cálcio > Zinco > Magnésio > Potássio > Manganês > Fósforo > Ferro > Níquel > Alumínio. Cujos valores retidos no solo das colunas podem estar evidenciando a capacidade deste solo em reter contaminantes.O solo em questão apresentou baixo potencial para retenção dos contaminantes presentes no lixiviado, classificado como arenoso e, com características químicas que não se enquadram nos parâmetros adequados para sua utilização em áreas de disposição de resíduos sólidos urbanos. / Recent studies had found the existence of processes that allow a natural attenuation of the leachates\'s cotaminants. An adequate understanding of these processes may originate benefits, that may be applied in ancient, new or to be created landfills. This work evaluated the contaminant\'s behavior and attenuation, contaminants existing in soil\'s leaching, throughout an experiment developed in percolation columns. This is the indicated examination for evaluate the attenuation, because it reflects soil\'s natural conditions and adsorptive characteristics, providing a better simulation of it\'s attenuation. The leachate and the soil used in this experiment came from Sao Carlos-SP landfill. The used soil has been characterized as its mineralogical\'s and physical chemical-biological\'s composition, looking for the percolated\'s transportation inside the columns, and for the interaction soil-contaminant. The landfill\'s area has been several times drilled, tested as it\'s hydraulic conductivity and assessment of local geology, in order to know the physical, chemical, biological, mineralogical and geological in situ soil\'s characteristics. This, has been classified as sandy, and, by presenting chemical characteristics that does not reach the adequated value for utilization on solid urban wastes, due to the values of CTC, SE, pH, and the textural sandy class, what shows a deficient buffering capacity in retaining and immobilisating contaminants. By observation in situ, has been found that Sao Carlos\'s solids disposal waste is located over rocks from the Botucatu formation, and the mineralogy of it is composed of quartz, caulinith, goethith, hematith, gibsith an ilith. The hydraulic conductivity test has indicated that the soil in the base of the sanitary landfill does not reaches the permeability values required by the standards, what may allow rain water\'s infiltration, and raises the amount of leachate and it\'s movement onto the ground, and even the leachete to reach the underground waters. So, has been drawn the characteristics curves of the contaminant\'s transportation in the effluents samples found during the percolation process, collected by every 0,25 VP until it reaches 10,0 VP percolated. The characteristical curves of the contaminant\'s transportation drawn showed low concentrations in the effluent samples of Lead, Cadmium, Iron, Zinc, Manganese, Calcium, Magnesium, Cooper, Chromium. Also, Sodium, Potassium, Chlorine, Nickel and Aluminium had been preferencially percolated within the leachate, what evidentiates the variation in the range of concentrations of every percolated element. The concentration profiles from heavy metal\'s had shown that there is a front of contamination. The retention curves from the soil\'s retaining metal showed that the preferency for the sorption was: Cooper > Cadmium > Calcium > Zinc > Magnesium > Potassium > Manganese > Phosphorus > Iron > Nickel > Aluminium, whose values may point the soil\'s ability in retaining contaminants. The studied soil has presented low potential in retain contaminants from the leachete, and is characterized as sandy, and it\'s chemical features shall not be framed according the standards parameters to be utilized in solid urban waste\'s disposal.

In order to make thermal solar power compete with the traditional sources of energy, the efficiency must increase and one way of doing it is by changing the operating fluid. Among the alternate fluids is the use of molten salts as a part of the process; either for thermal storage and later utilization for electrical production during the hours without sun or as a substitute of the operating fluid to provide higher temperatures resulting in better efficiency. The difficulty of using molten salts is the lack of physical properties in literature; such as viscosity, boiling point, vapor pressure and volumetric absorption of solar radiation, thus making the selection of a suitable salt a very difficult endeavor. As a part of the Multidisciplinary Research Initiative (MURI) of the Department of Energy in the project of High Operating Fluids, this work will focus on the optical properties of the molten salts (volumetric absorption). The objective of this Thesis is to design, build and test a device capable of measuring the light attenuation coefficient; which is directly related to volumetric absorption of solar radiation, as well as determine the attenuation coefficient of various eutectic systems for the ternary salt mixture of ZnCl2, NaCl and KCl. Based on the little existent literature, a device capable of measuring the attenuation coefficient was designed, built, validated and tested. This was done by projecting a stable beam of light simulating sun radiation through the molten salt sample and to a spectrometer with a wavelength range going from 400 nm to 1000 nm with operating temperatures going from 350oC to 600oC. This device is capable of controlling the thickness, from 1 to 60 mm, of the molten salt sample by a computer controlled linear stage with an accuracy of 0.1mm. Quartz was used as a container for the molten salts because of its high melting point and transparency. A ceramic heater was used as a heat source, which can heat up the sample to temperatures up to 1200 oC if necessary. Two validation tests for the device were done by measuring the light attenuation coefficient of clear water and extra virgin olive oil and then they were compared to the ones in literature. The eutectic systems were tested next; the results characterized the attenuation coefficient as a function of wavelength and temperature, something that no other experimental work has done before for this specific fluid. These values will help to determine an optimal operating fluid for high temperature thermal applications.

The inability of service providers to constantly meet the design target of 99.99 % availability of the line-of-sight (LOS) microwave links has caused concern among both the operators and consumers. The non-availability of the links is predominantly due to propagation impairments along the propagation link. These propagation effects include cloud, snow, fog, gas attenuation, rain and atmospheric scintillation. Various studies have shown high vulnerability of radio communication systems operating at microwave (3-30 GHz) and millimeter wave (30-300 GHz) to rainfall attenuation especially in the tropical regions characterized by heavy rainfall and relatively large rain drops when compared to the temperate regions. In order to understand the effects of attenuation due to rain on communication systems in any locality (region), a good knowledge of the raindrop size distribution (DSD) and the rainfall rate estimates is necessary for accurate prediction and estimation of the rainfall attenuation. For this study, experimental raindrop size measurements gathered over a period of three years, using the Joss-Waldvogel RD-80 disdrometer installed at the roof top of the Electrical, Electronic and Computer Engineering building, University of Kwa-Zulu Natal, Durban, a subtropical location in South Africa, is analysed. Disdrometer measurements, sampled at one-minute rate over a period of nine months from Butare, an equatorial site in Rwanda, is also analysed for the purpose of comparison. The estimated R0.01 values for Durban and Butare are employed for the purpose of analysis. Based on the statistical analysis of the measured data samples, DSD parameters are proposed from the negative exponential, modified gamma, Weibull and the lognormal models. The DSD models are compared to models from other countries within and outside the region. The Mie scattering approximation at temperature of 20oC for spherical raindrop shape is adopted for the estimation of the scattering functions. The study further investigates the influence of critical raindrop diameters on the specific rain attenuation for the annual, seasonal and various rainfall regimes in southern Africa. This is achieved analytically by integrating the total rainfall attenuation over all the raindrop sizes and observing the differential change in the attenuation over a given range of drop size diameters. The peak diameter at which the specific rainfall attenuation is maxima is determined for different rainfall regimes. Finally, the cross-polarisation discrimination (XPD) due to rain over Durban is computed at two elevation angles. The results of this study will be helpful for the proper design and allocation of adequate fade margins to achieve the expected quality of service (QoS) in a radio communication system operating in the Southern Africa region. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2014.

Ultrasonic wave attenuation measurements have been used to successfully characterize the microstructure and material properties of inhomogeneous materials; these ultrasonic techniques have the potential to provide for the in situ characterization of heterogeneous, cement-based materials. Recent research has applied existing acoustic scattering models to predict ultrasonic attenuation in relatively simple cement-based materials with good results. The goal of the current research is to extend this past work and to investigate the influence of elastic inclusions in order to simulate a more realistic microstructure: a cement paste matrix material that contains both sand inclusions and air voids. The sand inclusions simulate fine aggregates as they are present in real civil engineering structures, while the air voids provide an additional microstructure that is present in concrete components. This research considers an independent scattering model as well as a self-consistent effective medium theory approach in order to model the scattering attenuation due to the sand inclusions in the cement paste matrix. The research develops a reliable measurement technique essential to assess the wave attenuation of the particulate materials. Subsequently, the ultrasonic wave attenuation is measured in cement paste specimens of various types. The measured attenuation is then compared to the model predictions and the results are discussed. Finally, theoretical approaches to model the described three-phase materials are presented and discussed.

Estudos recentes constataram a existência de processos que permitem a atenuação natural dos contaminantes presentes nos lixiviados. O adequado entendimento destes processos pode originar benefícios possíveis de serem aplicados em aterros antigos, novos ou naqueles que ainda serão concebidos. O presente estudo avaliou o comportamento e a atenuação de contaminantes dos líxiviados no solo, por meio de experimento desenvolvido em colunas de percolação e, para a avaliação da atenuação este teste é indicado por refletir as condições naturais e as características adsortivas do solo, propiciando uma melhor simulação da atenuação. O lixiviado e o solo utilizados neste experimento são provenientes do aterro sanitário de São Carlos - SP. O solo utilizado foi caracterizado quanto à composição física, química, biológica e mineralógica para verificar o transporte do percolado nas colunas e a interação solo-contaminante. Na área do aterro foram feitas perfurações, ensaios de condutividade hidráulica e avaliação da geologia local, para conhecimento das características físicas, químicas, biológicas, mineralógicas e geológicas do solo in situ. Este foi classificado como arenoso, apresentando características físicas e químicas que não se enquadram nos parâmetros adequados para sua utilização em áreas de disposição de resíduos sólidos urbanos, pois, a capacidade de troca de cátions, superfície específica, potencial hidrogeniônico e classe textural arenosa, evidenciam que este solo possui deficiente capacidade de retenção e imobilização de contaminantes. Além disso, pela observação in situ, constata-se que a área de disposição de resíduos sólidos de São Carlos esta situado sobre rochas da Formação Botucatu, sendo que a mineralogia do solo presente no local é composta de quartzo, caulinita, goethita, hematita, gibsita e ilita. O ensaio de condutividade hidráulica indicou que o solo presente na base do Aterro sanitário não atende a valor de permeabilidade exigida por norma, o que poderá permitir a infiltração de água da chuva, aumentando a produção do lixiviado e sua movimentação no perfil, podendo atingir as águas subterrâneas. Assim, foram traçadas curvas características do transporte de contaminantes nas amostras efluentes monitoradas durante o processo de percolação, coletadas a cada 0,25 volume de poros até atingir 10,0 volume de poros percolados. As curvas características do transporte de contaminantes traçadas apresentaram baixas concentrações de Chumbo, Cádmio, Ferro, Zinco, Manganês, Cálcio, Magnésio, Cobre, Cromo nas amostras fluentes. Já o Sódio, Potássio, Cloro, Níquel e Alumínio foram preferencialmente percolados com o lixiviado, evidenciando a variação da faixa de concentração de cada elemento no percolado. Os perfis de concentração dos metais pesados mostraram que existe uma frente de contaminação. As curvas de retenção de metais no solo mostraram que a preferência de sorção apresentada pelos solos nas colunas foi : Cobre > Cádmio > Cálcio > Zinco > Magnésio > Potássio > Manganês > Fósforo > Ferro > Níquel > Alumínio. Cujos valores retidos no solo das colunas podem estar evidenciando a capacidade deste solo em reter contaminantes.O solo em questão apresentou baixo potencial para retenção dos contaminantes presentes no lixiviado, classificado como arenoso e, com características químicas que não se enquadram nos parâmetros adequados para sua utilização em áreas de disposição de resíduos sólidos urbanos. / Recent studies had found the existence of processes that allow a natural attenuation of the leachates\'s cotaminants. An adequate understanding of these processes may originate benefits, that may be applied in ancient, new or to be created landfills. This work evaluated the contaminant\'s behavior and attenuation, contaminants existing in soil\'s leaching, throughout an experiment developed in percolation columns. This is the indicated examination for evaluate the attenuation, because it reflects soil\'s natural conditions and adsorptive characteristics, providing a better simulation of it\'s attenuation. The leachate and the soil used in this experiment came from Sao Carlos-SP landfill. The used soil has been characterized as its mineralogical\'s and physical chemical-biological\'s composition, looking for the percolated\'s transportation inside the columns, and for the interaction soil-contaminant. The landfill\'s area has been several times drilled, tested as it\'s hydraulic conductivity and assessment of local geology, in order to know the physical, chemical, biological, mineralogical and geological in situ soil\'s characteristics. This, has been classified as sandy, and, by presenting chemical characteristics that does not reach the adequated value for utilization on solid urban wastes, due to the values of CTC, SE, pH, and the textural sandy class, what shows a deficient buffering capacity in retaining and immobilisating contaminants. By observation in situ, has been found that Sao Carlos\'s solids disposal waste is located over rocks from the Botucatu formation, and the mineralogy of it is composed of quartz, caulinith, goethith, hematith, gibsith an ilith. The hydraulic conductivity test has indicated that the soil in the base of the sanitary landfill does not reaches the permeability values required by the standards, what may allow rain water\'s infiltration, and raises the amount of leachate and it\'s movement onto the ground, and even the leachete to reach the underground waters. So, has been drawn the characteristics curves of the contaminant\'s transportation in the effluents samples found during the percolation process, collected by every 0,25 VP until it reaches 10,0 VP percolated. The characteristical curves of the contaminant\'s transportation drawn showed low concentrations in the effluent samples of Lead, Cadmium, Iron, Zinc, Manganese, Calcium, Magnesium, Cooper, Chromium. Also, Sodium, Potassium, Chlorine, Nickel and Aluminium had been preferencially percolated within the leachate, what evidentiates the variation in the range of concentrations of every percolated element. The concentration profiles from heavy metal\'s had shown that there is a front of contamination. The retention curves from the soil\'s retaining metal showed that the preferency for the sorption was: Cooper > Cadmium > Calcium > Zinc > Magnesium > Potassium > Manganese > Phosphorus > Iron > Nickel > Aluminium, whose values may point the soil\'s ability in retaining contaminants. The studied soil has presented low potential in retain contaminants from the leachete, and is characterized as sandy, and it\'s chemical features shall not be framed according the standards parameters to be utilized in solid urban waste\'s disposal.

This diploma thesis deals with ultrasound attenuation measurement methods. Variety of methods are developed and tested . Castor oil was used as reference material. Different kinds of ultrasound transducers, hydrophone and ultrasound scanner GE Vingmed SystemFive were used for measurement. Data was processed by scripts developed in matlab.

京都大学 / 0048 / 新制・課程博士 / 博士(地球環境学) / 甲第22619号 / 地環博第198号 / 新制||地環||38(附属図書館) / 京都大学大学院地球環境学舎地球環境学専攻 / (主査)教授 勝見 武, 教授 高岡 昌輝, 准教授 高井 敦史 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM

ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / This paper discusses the effect of vehicle exhaust plasma/plume on the ability to receive telemetered data via an S-band RF link. The data presented herein were captured during the launch of the STARS FT-04-1 on February 23, 2006 from Kodiak Launch Center, Kodiak, Alaska using Alaska Aerospace Development Corporation’s (AADC) Range Safety and Telemetry System (RSTS), designed and integrated by Honeywell.