932 resultados para genesis of coal


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The catalytic and accelerating effects of three coal-burning additives (CBA) on the burning of graphite were studied with the help of thermogravimetric (TG) analysis. The kinetic study on the catalytic oxidation of the graphite doped with CBA was carried out and the results were presented. The results show that the CBA can change the carbon oxidation/combustion course by catalytic action and change the activation energy, thus improving the combustion efficiency.

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In the U.S., coal fired power plants produce over 136 million tons of coal combustion residuals (CCRs) annually. CCRs are enriched in toxic elements, and their leachates can have significant impacts on water quality. Here we report the boron and strontium isotopic ratios of leaching experiments on CCRs from a variety of coal sources (Appalachian, Illinois, and Powder River Basins). CCR leachates had a mostly negative δ(11)B, ranging from -17.6 to +6.3‰, and (87)Sr/(86)Sr ranging from 0.70975 to 0.71251. Additionally, we utilized these isotopic ratios for tracing CCR contaminants in different environments: (1) the 2008 Tennessee Valley Authority (TVA) coal ash spill affected waters; (2) CCR effluents from power plants in Tennessee and North Carolina; (3) lakes and rivers affected by CCR effluents in North Carolina; and (4) porewater extracted from sediments in lakes affected by CCRs. The boron isotopes measured in these environments had a distinctive negative δ(11)B signature relative to background waters. In contrast (87)Sr/(86)Sr ratios in CCRs were not always exclusively different from background, limiting their use as a CCR tracer. This investigation demonstrates the validity of the combined geochemical and isotopic approach as a unique and practical identification method for delineating and evaluating the environmental impact of CCRs.

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Following a thorough site investigation, a biological Sequential Reactive Barrier (SEREBAR), designed to remove Polycyclic Aromatic Hydrocarbons (PAHs) and BTEX compounds, was installed at a Former Manufactured Gas Plant (FMGP) site. The novel design of the barrier comprises, in series, an interceptor and six reactive chambers. The first four chambers (2 nonaerated-2 aerated) were filled with sand to encourage microbial colonization. Sorbant Granular Activated Carbon (GAC) was present in the final two chambers in order to remove any recalcitrant compounds. The SEREBAR has been in continuous operation for 2 years at different operational flow rates (ranging from 320 L/d to 4000 L/d, with corresponding residence times in each chamber of 19 days and 1.5 days, respectively). Under low flow rate conditions (320-520 L/d) the majority of contaminant removal (>93%) occurred biotically within the interceptor and the aerated chambers. Under high flow rates (1000-4000 L/d) and following the installation of a new interceptor to prevent passive aeration, the majority of contaminant removal (>80%) again occurred biotically within the aerated chambers. The sorption zone (GAC) proved to be an effective polishing step, removing any remaining contaminants to acceptable concentrations before discharge down-gradient of the SEREBAR (overall removals >95%).

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The interactions of coal with CO2 at pressures of up to 30 bar concerning mechanisms of diffusion, the strength of interactions, and the irreversibility of uptake for the permanent disposal of CO2 into coal fields have been studied. Differential scanning calorimetry was used to investigate coal/CO2 interactions for North Dakota, Wyodak, Illinois No. 6, and Pittsburgh No. 8 coals. It was found that the first interactions of CO2 with coals led to strongly bound carbon dioxide on coal. Energy values attributed to the irreversible storage capacity for CO2 on coals were determined. The lowest irreversible sorption energy was found for North Dakota coal (0.44 J/g), and the highest value was for the Illinois No. 6 coal (8.93 J/g). The effect of high-pressure CO2 on the macromolecular structure of coal was also studied by means of differential scanning calorimetry. It was found that the temperature of the second-order phase transition of Wyodak coal decreases with an increase in CO2 pressure significantly, indicating that high-pressure CO2 diffuses through the coal matrix, causes significant plasticization effects, and changes the macromolecular structure of the Wyodak coal. Desorption characteristics of CO2 from the Pittsburgh No. 8 coal were studied by temperature-programmed desorption mass spectrometry. It was found that CO2 desorption from the coal is an activated process and follows a first-order kinetic model. The activation energy for CO2 desorption from the Pittsburgh No. 8 coal increased with the preadsorbed CO2 pressure, indicating that CO2 binds more strongly and demands more energy to desorb from the Pittsburgh No. 8 coal at higher pressures.

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We study the dynamics of two strongly interacting bosons with an additional impurity atom trapped in a harmonic potential. Using exact numerical diagonalization we are able to fully explore the dynamical evolution when the interaction between the two distinct species is suddenly switched on (quenched). We examine the behavior of the densities, the entanglement, the Loschmidt echo, and the spectral function for a large range of interspecies interactions and find that even in such small systems evidence of Anderson's orthogonality catastrophe can be witnessed.

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This chapter outlines the working methods of the prolific writer and lyricist Thomas Moore—which were characterized by the unfortunate combination of a perfectionist streak, a tendency to release material to the publishers while still in the creative mode, and a tendency to re-visit previously-published material. The Gibson-Massie Moore collection at Queen's University Belfast teaches us a great deal about Moore’s creative processes, and also records the nineteenth-century publishing industry’s response to one of its most prolific and popular creative artists. This chapter is illustrated by an online Exhibition, the 'Thomas Moore Project', Digital Collections, Special Collections, McClay library (see URL below).

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This is a selection of images from the Gibson-Massie Moore Collection, supplement by a table created by curator Sarah McCleave. The purpose is to identify the numerous creators involved in the Irish Melodies series (music editor, illustrators, engravers, etc.), and to illustrate some characteristics kinds of variants

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Tese de doutoramento, Geologia (Metalogenia), Universidade de Lisboa, Faculdade de Ciências, 2014

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This paper aims to survey metal concentrations in soils in the vicinity of a coal-firedpower plant located in southwest of Portugal. Two annual sampling campaigns were carried out to measure a hypothetical soil contamination around the coal plant. The sampling area was divided into two subareas, both centered in the emission source, delimited by two concentric circles with radius of 6 km and 20 km. About 40 samplings points were defined in the influence area. Metals measurements were performed with a portable analytical X-ray dispersive energy fluorescence spectrometer identifying about 20 different elements in each sampling point. The most relevant elements measured included As, Cu, Fe, Hg, Pb, Ti and Zn in both sampling areas. Considering the results obtained in the first sampling campaign, arsenic is predominantly higher within the 6-20 km sampling area. The second sampling campaign showed that both sampling areas presented relatively similar metal concentrations except for Fe, Mn, Sr and Zn which concentration is higher within the 6-20 km sampling area. Also, As, Fe, Mn and Ti concentrations decreased significantly from the first to the second sampling campaign and their concentration were predominately higher in the NE-E and E-SE directions.