No abstract was provided. / Thesis / Master of Engineering (ME)

This thesis examines potential improvements to current coal mine fire response measures. In the event of a fire scenario, indirect testing and analysis of the exhausting air is needed to characterize changes in the fire. The application of multiple passive source tracers provides improved detail of complex ventilation interactions over an extended period of time. The first work in this thesis details the testing of the passive release rates for three Perfluorocarbon tracer compounds over a 180-day period. The results of this study demonstrate the ability for the permeation plug release vessel design to release Perfluorocarbon tracers at a steady rate. Current response methods for a fire in a coal mine gob consist of injection of inert gas and sealing of the mine openings. Injection of high expansion foam into the gob from the surface has potential to improve extinguishment of the fire and reduce the time needed to bring the mine back to an operational state. The applicability of this method requires computational modeling and field testing. The second part of this thesis determines the Darcy and Forchheimer values for high expansion foam flow in simulated gob material with a lab experiment. The experiment was replicated in the CFD software, OpenFOAM, to validate the methods for calculation of the Darcy and Forchheimer values. The results of this study provide a tested methodology for a future full scale modeling of high expansion foam injection in a coal mine gob. / Master of Science / This thesis examines potential improvements to current coal mine fire response measures. In the event of a mine fire, indirect testing of mine air exhaust is needed to track changes in the fire. The use of multiple passive tracer gas testing allows for better detail of air movement over a longer period of time. The first work in this thesis details the testing of the gas release rates for three Perfluorocarbon tracer gases over a 180-day timeframe. The results of this study show the ability for the gas release design to release Perfluorocarbon tracers at a steady rate needed for mine air exhaust testing. Current methods to extinguish a fire in a coal mine gob involve adding inert gas to the mine and sealing the mine openings. Pumping of high expansion foam into the caved area of the coal mine from the surface has potential to improve extinguishment of the fire and reduce the time needed to bring the mine back to normal conditions. The potential of this method is determined by computer simulations and lab testing. The second part of this thesis determines the characteristics for foam flow in simulated caved material. The lab test was replicated in a computer simulation to prove the methods used to characterize the foam flow were accurate. The results of this study provide a proven method for future full scale computer simulations of foam flow in the caved area of a coal mine.

O objetivo deste estudo foi aplicar técnicas de geoquímica de elementos maiores, menores e isótopos de Sr e Nd para identificar contaminação por fosfogesso em sedimentos fluviais da bacia hidrográfica Mogi/Piaçaguera. Para isto, foram analisados perfis de sedimento das margens dos rios Cubatão, Pereque, Mogi (montante, meio e jusante), Piaçaguera e Jurubatuba, inseridos no alto estuário santista, assim como solos, rochas e águas superficiais. Os métodos utilizados foram fluorescencia e difratometria de raios-x, microscopia ótica e analises isotópicas de Sr e Nd. Os resultados demonstraram fator de enriquecimento de Sr, Nd, Nb, La, F e Ce nos sedimentos superficiais do Rio Mogi jusante, comparado aos demais sedimentos fluviais analisados. As composições isotópicas dos sedimentos fluviais regionais foram dentro do padrão das rochas e solos da bacia hidrográfica. A exceção se deve aos sedimentos fluviais superficiais do Rio Mogi jusante que apresentaram assinaturas química e isotópica semelhantes do fosfogesso. O cálculo de proporção de mistura de composições isotópicas de Sr e Nd proveniente do fosfogesso indicou significativa discrêpancia para os dois métodos, de até 6% para Sr e 35% para Nd. Pelo contrário, diagramas 143Nd/144Nd e 87Sr/86Sr apresentaram proporções menores de 10%, coerentes com estudo da literatura que estimou de 13% a 18% a solubilização do fosfogesso em água. A normalização das composições isotópicas com a água do mar (e87Sr) dos resultados para extração parcial (ácido acético) indicou valores de e87Sr semelhantes para solos, sedimentos e águas superficiais da bacia hidrográfica, inclusive, levanta-se hipotese da influência da maré nos sedimentos do Rio Jurubatuba, com padrão isotópico semelhante da água do mar. Distintamente, confirmaram-se assinaturas isotópicas do fosfogesso nos sedimentos do Rio Mogi jusante. Em suma, isotopos de Sr e Nd demonstraram ser importantes ferramentas na identificação de plumas de contaminação antrópica, como também na identificação das prováveis fontes destas anomalias. / This objective of this study was applying geochemical techniques of major and minor elements, aswell as Sr. And Nd isotopes to identify contamination by phosphogypsum in fluvial sediments in the hydrografic basin of Mogi/Piaçaguera. Profiles of sediments from Cubatão, Pereque, Mogi (upstream,middle and downstream), Piaçaguera and Jurubatuba rivers margins, inserted in the high Santista stuary, as well as soils, rocks and superfial waters were analysed. The methods used were fluorescence and difratometria of X-rays, optical microscopy and isotopic analyses of Sr and ND. The results showed a factor of enrichment of Sr. Nd. NB, La, F and Ce in surface sediments of the Rio Mogi jusante, compared to other fluvial sediments analysed. The isotopic compositions of regional fluvial sediments were in accordance with rocks pattern and the hydrografic basin soils. The exception is due to surface fluvial sediments of the Rio Mogi jusante, which showed chemical and isotopic signatures similar to phosphogypsum. The calculation of proportion of isotopic composition mixtures of Sr. And Nd resulted from phosphogypsum indicated a significative discrepance for these two methods of up to 6% to Sr and 35% to Nd. On the contrary, 143Nd/144Nd and 87Sr/86Sr dyagrams presented minor proportions of 10% in coherence with the literature study, which estimated 13% to 18% the solubilization of phosphogypsum in water. The isotopic compositions normalization with sea water (e87Sr) of results for partial extraction (accectic acid) showed the value of e87Sr similar for soils, sediments and surface waters of the hydrografic basin. The hypotesis of the tidal influence in sediments of Rio Jurubatuba was arised, with a isotopic pattern similar to sea water. In a distinct way, the isotopic signatures of phosphogypsum in sediments of Rio Mogi jusante were confirmed. In summary,isotopes of Sr and Nd showed that are significant tools in the identification of plumas of antropic contamination, as well as in the identification of probable sources of these anomalies.

The dynamic behavior of a pilot flotation column has been studied using the tracer technique. Radioactive tracers emitting gamma radiation have been used for this purpose. Since this is a three-phase system (air, water, and solid particles), having one entrance port and two exit flows, the residence time distribution (RTD) has been determined for both the liquid and solid phases. Moreover, the solids RTD has also been separately measured for four distinct size fractions, i.e. four determinations in all. Instantaneous pulse injections were performed in the feed flow and detected by scintillation probes with sodium iodide crystals doped with thallium, NaI(Tl), adequately collimated and placed at the tails and concentrate exit sections. The detector signals were duly counted, processed, and stored by a computer. This setup allowed the RTD identification at the concentration and washing sections of the column to be directly obtained from the detector responses, without any interference whatsoever with the column operation regime. All the plant operational parameters were duly logged. An injection device was designed to introduce the tracer as close as possible to the column entrance and as instantaneously as feasible, thus simulating a Dirac delta impulse. A probe placed immediately downstream the injection position has been used to check its performance. The Peclet number (Pe) and the average residence time ( t ) were the system parameters determined by fitting the axial dispersion model to the experimental data. The model boundary conditions tested corresponded to the closed-closed, and open-closed B.C.s simulating the entrance-exit boundaries. It was demonstrated that recovery decreases with increasing the collect zone degree of mixing. By labeling both phases, the influence of the particle size distribution on the hydrodynamic behavior of the solids, as well as on the divergent behavior of the solid and liquid phases, has also checked. The closed-closed and open-closed boundary parameters obtained with experimental data allowed the collect zone rate constant determination. Wash water influence in solids hydrodynamic behavior was also checked. Industrial tests allowed confirming the steady state operation conditions of the studied systems and observing stagnant zones inside them. The solid and liquid phase tracers were produced by irradiation under a neutron flux inside the IPR-R1 TRIGA MARK II nuclear reactor at CDTN/CNEN. For labeling the liquid phase, 56Mn has been chosen for pilot scale, and 82Br for industrial scale. For the solid phase the irradiated ore itself has been used. 140La and 153Sm were the two main gamma emitter radioisotopes detected in the activated ore. / Nesse trabalho foi realizado um estudo do comportamento dinâmico de uma coluna de flotação piloto através do uso da técnica de traçadores radioativos emissores gama. Também foi avaliada a aplicação da técnica em um condicionador e uma coluna de flotação em escala industrial. Como a flotação em coluna é um sistema trifásico (ar, água e partículas minerais), foi determinada a distribuição dos tempos de residência (DTR) tanto para a fase líquida quanto para a sólida, sendo as medições nesta última realizadas em quatro diferentes frações granulométricas. Foram feitas injeções pulsadas do traçador no fluxo de alimentação e registradas suas respostas usando detectores de cintilação de iodeto de sódio ativados com tálio, NaI (Tl), devidamente colimados posicionados às saídas do rejeito e do concentrado da coluna. Isto possibilitou a identificação direta da DTR dessas regiões sem nenhuma interferência sobre o seu regime de operação. Todas as informações sobre as condições operacionais da coluna durante os experimentos foram devidamente registradas. Para a injeção do traçador foi desenvolvido um sistema injetor na tubulação da alimentação, imediatamente antes da entrada na coluna, garantindo um pulso instantâneo o mais próximo possível do ideal (função Delta de Dirac). Este desempenho foi comprovado posicionando um terceiro detector de NaI (Tl) logo após o sistema de injeção. Alguns parâmetros como o número de Peclet (Pe) e o tempo médio de residência ( t ) foram determinados através de ajustes dos dados experimentais aos modelos de dispersão axial, com as condições de contorno descritas na literatura: aberto-aberto, fechado-fechado, abertofechado. Esses parâmetros permitiram demonstrar a influência das condições de mistura da zona de coleta da coluna sobre a recuperação metalúrgica do processo. Foi quantificada a influência da granulometria no comportamento hidrodinâmico do minério e as diferenças entre o comportamento deste e o da fase líquida. Os parâmetros determinados na marcação da fase sólida permitiram que a constante cinética da zona de coleta fosse determinada através da solução da equação da dispersão axial para o sistema fechado-fechado e aberto-fechado. Ficou demonstrada também a influência da água de lavagem no comportamento das distintas frações granulométricas marcadas. Em escala industrial foi possível diagnosticar informações importantes a cerca dos sistemas em estudo como a presença de regiões de fluxo estagnado e a confirmação das operações em estado estacionário. Os traçadores da fase líquida e sólida foram produzidos através da exposição destes a um fluxo de nêutrons no reator nuclear TRIGA do CDTN/CNENPara marcação da fase líquida foi utilizado o radioisótopo 56Mn na forma de um sal (MnCl2) diluído em água. Para a fase sólida, uma alíquota do próprio minério processado foi irradiada no reator. Os radioisótopos 140La e 153Sm foram os principais emissores gama detectados no minério ativado.

Background: Indoor air contaminants generally have a greater impact on health than outdoor air contaminants, which increases the importance of a dependable, accessible, and minimally impactful method for measuring indoor air exchange rates. Objective: Evaluate the use of naturally generated CO2 as a tool to measure indoor ventilation. Methods: Indoor CO2 levels were measured over seven sample intervals in an airtight one-bedroom apartment with two residents. High frequency noise was removed from the measurements with Fourier, Kalman, LOESS, and rolling average filters. Root-mean squared errors (RMSE) between filtered and measured CO2 were calculated and compared for each sample interval and filter pair. A multivariable linear regression was used to assess differences between digital filters. Local minima and maxima were identified to calculate air exchange rates. The R statistical software was used for all data management and analysis. Results: The RMSE for all filter types had geometric standard deviations between one and two, indicating that all filters were stable across sample intervals. Results of the multivariable linear regression indicate that the RMSE of the Fourier filter were significantly lower than those of the Kalman filter with a P-value ofConclusions:The Fourier filter performed best based on visual analysis and RMSE comparisons. All filters except for the rolling average filter identified the majority of primary local minima/maxima effectively.

No description available.

The Middle San Pedro Basin in southeastern Arizona is a typical alluvial basin in the semi-arid southwestern United States with a rapidly growing population that is dependent upon groundwater resources for water supply. This study investigated recharge areas, compartmentalization and potential mixing of water sources, and travel times of groundwater throughout the basin using variations in major ion chemistry (water type, Ca/Sr ratios, SO4/Cl ratios) and isotope ratios (18O, 2H, 3H, 34S, 13C, 14C) of groundwaters, surface waters and precipitation in conjunction with hydrogeologic data (e.g. hydraulic head and hydrostratigraphy). Recent recharge (<50 years) has occurred within mountain systems along the basin margins, and in shallow floodplain aquifers adjacent to the San Pedro River. Groundwaters in confined aquifers in the central basin were recharged at high elevation in the fractured bedrock and have been extensively modified by water-rock reactions over long timescales (up to 34,600 years). These results can be used to constrain physical assumptions of future groundwater flow models designed to help make improved water management decisions.

This research examined field measurements and the HYDRUS 1-D (version 4.12) model to quantify annual movement of NO3-N through two soils of different HSG groups (B and C) using a Cl tracer and examine leaching losses attributed to the winter months (November 2007 – April 2008). Field and model data confirmed potential leaching losses ~ 72% (Cl mass recovery) over these months. Differences in Cl and nitrate-N mass recovery indicated potential N losses via other processes such as denitrification and/or immobilization. The 200 kg N ha-1 treatment was most indicative; site’s B and C had 1% and 9% losses, respectively. Both sites exhibited ~ 96-99 % loss of soil nitrate-N and Cl of the fall-applied N and Cl by September 2008. Monthly crop sampling demonstrated ~ 1% soil mineral-N remained at harvest (November 2008). These findings further support the effectiveness of applying N in the spring than the fall. / M.Sc. Thesis / Agriculture and Agri-Food Canada, Ontario Ministry of Agriculture, Food and Rural Affairs and the Canadian Water Network

Remediation of DNAPL contaminated sites in fractured rock has proven to be very difficult. No current technology can be used to remediate such sites in a timely and economic manner due to the inherent heterogeneity of fractured rock and back diffusion of contaminants stored in the rock matrix. This study was conducted in order to evaluate the viability of biostimulation of native biofilm as a means to control flow and back diffusion at fractured rock sites. A field trial was conducted at an uncontaminated site in southern Ontario. The site is underlain by dolomites of the Lockport formation. Three major fracture zones have been identified in the study area. Two closely spaced (5.04 m) boreholes were used to isolate a fracture zone at a depth of 17 m with straddle packers. These boreholes were used to create an injection-withdrawal system with recirculation, which was used for tracer injection in order to load the rock matrix with a conservative dye tracer and to inject nutrients for 21 days in order to stimulate the growth of biofilm in the fracture. Evaluation of the ability of the biofilm to control flow through the fracture was conducted through pulse interference tests. Pulse interference tests were conducted before and after the injection of nutrients. The results from the pulse interference tests showed a maximum 65% reduction in transmissivity, which is equivalent to a 28% reduction in fracture aperture shortly after the cessation of biostimulation. In order to investigate the effect of the biofilm stimulation on matrix diffusion the rock matrix was loaded with Lissamine, a conservative fluorescent dye tracer prior to biostimulation and its concentration was monitored at injection and withdrawal wells. The effect that biostimulation had on matrix diffusion was determined by comparing field concentration measurements with a model that simulates a system unaffected by biofilm stimulation. The biostimulation lowered the concentration of tracer attributable to back diffusion at the withdrawal well by about 20% for approximately 30 days following the cessation of biostimulation. It is also thought that large amounts of tracer might have been trapped in the biofilm as it formed and was then released back into the fracture as the biofilm deteriorated. / Thesis (Master, Civil Engineering) -- Queen's University, 2009-08-11 19:27:44.232

Natural attenuation of trichloroethene (TCE) and technetium (99Tc) was studied for five consecutive seasons (from January 2002 to January 2003) in Little Bayou Creek. The stream receives ground water discharge from an aquifer contaminated by past waste disposal activities at the Paducah Gaseous Diffusion Plant (PGDP), a uranium enrichment facility near Paducah, Kentucky. Results from stream gaging, contaminant monitoring, tracer tests (with bromide, nitrate, rhodamine WT and propane) and simulation modeling indicate the TCE is naturally attenuated by volatilization and dilution, with volatilization rates related to the ambient temperature and surface discharge rate. The only apparent mechanism of 99Tc attenuation is dilution. Travel times of non-gaseous tracers were found to be similar and have highest values in October and lowest in June. It was also estimated from modeling that the transport of the solutes in the stream was mostly one-dimensional with insignificant secondary storage.