This work takes a closer look at ceria catalyst synthesis through micelle self-assembly. We compare surfactants, precursors, solvent systems, and doping. The surfactants are the building blocks upon which the ceria can crystallize. The samples are calcinated to test their thermal stability. Characterization is performed using pXRD as well as physisorption. The samples that exhibited a higher thermal stability were characterized to have a high surface area as well as low fluctuations in crystallite size, pore volume, and pore size. Ceria synthesized with cerium (III) nitrate hexahydrate and CTAB in a water:ethanol mixture using sodium hydroxide showed to be the most effective at providing a thermally stable product. Doping the catalyst with titanium increased the thermal stability significantly. Select samples were run in a variety of fuel to oxygen ratios to determine the best conditions in which we could perform partial methane oxidation to recuperate hydrogen gas. Most of the experiments show oxygen depletion with minor changes in other gas levels indicating that there is no oxidation occurring. Curiously the oxygen levels do decrease. There is a possibility that there is a reaction occurring initially at room temperature and being exacerbated with further temperature increase.

Methane (CH₄) production from enteric fermentation in ruminant animals is a contributor to global greenhouse gas emissions. Because CH₄ has an impact on increasing global temperatures, there is a push for government regulations to reduce CH₄ from livestock animals. At 1.9% of U.S. CH₄ emissions beef cattle are a large contributor to agricultural CH₄ emissions or (EPA, 2020). Enteric CH₄ emissions are also a loss of energy for the animal, accounting for 2-12% of energy loss from the ruminant animal (Johnson & Johnson, 1995). This energy loss from the diet is contingent upon forage content, where increasing forages in the diet increases CH₄ yield (g/kg of gross energy intake; van Gastelen et al., 2019). Mootral is a feed supplement that contains garlic (<i>Allium sativum</i>) and bitter orange (<i>Citrus aurantium</i>) extracts. The organosulfur compounds in garlic the flavonoids found in bitter orange extracts are known to decrease CH₄ production, (Busquet et al., 2005a; Balcells et al., 2012; Seradj et al., 2014). However, it is unclear how the forage content and Mootral inclusion will interact to effect CH₄production and animal performance. Because feedlot cattle are fed a range of forage:concentrate ratios while in the feedlot, it is important to know how effective mitigation strategies are in different forage:concentrate diets. Therefore, the objective of the current study was to quantify CH₄ production and determine growth, intake, and carcass characteristics of feedlot steers fed Mootral in diets with a low, medium, and high forage content. Knowing the effect of garlic and flavonoids on methanogenesis, we hypothesized that Mootral would decrease CH₄ emissions without impacting growth, intake, and carcass characteristics of feedlot steers. We expect that the CH₄ mitigating ability of Mootral will be greatest in the diet with the most forage. For the experiment, 144 Angus x Simmental steers were allotted by body weight (BW; 363 kg, breed composition, and farm origin to a 3 x 2 factorial arrangement of 6 treatments (4 pens per treatment) to determine the effect of Mootral (garlic + citrus extract; 0.25% of the diet DM vs. 0.0%) on methane emissions, growth and carcass characteristics of feedlot cattle. During the first 84 days, cattle were fed three different forage concentrations in the diet (15, 41.5, or 68% corn silage) with or without Mootral. From day 85 to slaughter, corn silage was included at 15% of the diet DM with or without Mootral. Methane emissions were measured on day 42-46 and day 203-207. Data were analyzed using the GLIMMIX procedure of SAS. There was an interaction (<i>P </i>= 0.03) between forage content and Mootral for DMI from d 0 to 84, where Mootral decreased DMI of steers fed 15% corn silage but did not affect DMI of steers fed 41.5 or 68% corn silage. There were no effects (<i>P </i>≥ 0.22) of forage content or Mootral on BW or average daily gain at any time, or on DMI from d 84 to slaughter and overall. Intake from d 0-84 was lower and gain:feed from d 0-84 and overall was greater (<i>P </i>= 0.04) for steers fed 68% compared to 15 or 41.5% corn silage. On d 42-46, steers fed 41.5 and 68% corn silage had increased (<i>P </i>≤ 0.02) methane emissions compared to steers fed 15% corn silage. Mootral did not affect methane emissions on day 42-46 (<i>P</i> ≥ 0.47), but there was a forage effect, where steers fed the 41.5 and 68% corn silage diets emitted more methane on a g/d (<i>P</i> = 0.05) and a g/kg of DMI (<i>P</i> = 0.007) basis and tended (<i>P</i> = 0.07) to produce more methane on g/kg BW basis compared to steers fed the 15% corn silage diet. Steers fed Mootral emitted less (<i>P </i>≤ 0.03) methane on a g/d, g/kg DMI, and g/kg BW basis on d 203-207 compared to steers not fed Mootral. Mootral tended to decrease (<i>P </i>≤ 0.09) fat thickness and yield grade. In conclusion, increasing forage content increased methane emissions and Mootral decreased methane production in 15% corn silage diets and improved carcass leanness.

Orientador: Telma Teresinha Berchielli / Coorientador: Juliana Duarte Messana / Banca: Eduardo Henrique Bevitori Kling de Moraes / Banca: Otavio Rodrigues Machado Neto / Banca: Paulo Henrique Moura Dian / Banca: Yury Tatiana Granja Salcedo / Resumo: Exp. 1 e 2: Foi avaliado o efeito de dois planos nutricionais (PN) sobre o consumo, digestibilidade, desempenho e emissão de metano (CH4), parâmetros fermentativos, eficiência de síntese microbiana e bactérias ruminais de três grupos genéticos (GG), na fase de recria, em pastagem. Cento e sessenta e dois tourinhos Nelore, cruzados ½Senepol e cruzados ½Angus, foram utilizados em um delineamento em blocos casualizados, arranjo fatorial 2 × 3, com idade média de 10 ± 2 meses e peso corporal inicial de 262 ± 31 kg, no experimento de desempenho. Doze tourinhos, sendo quatro de cada GG (Nelore, Senepol e cruzados ½Angus), canulados no rúmen, com idade média de 16 ± 2 meses e peso corporal inicial de 411 ± 34 kg, no experimento de metabolismo. Ambos foram alocados em doze piquetes de Urochloa brizantha (A. Rich.) Stapf. cv. Xaraés, submetidos a dois PN: suplementação com mineral (SM) 30 g / 100 kg peso corporal (PC) ou concentrado (SC) 300 g / 100 kg de PC. No experimento de desempenho o PN com SC proporcionou maior consumo de nutrientes e digestibilidade de PB e EE e maior AOL e EG (P < 0,05). Cruzados ½Senepol apresentaram maior digestibilidade de MS, MO e PB que Nelore e ½Angus (P < 0,05). Porém, Nelore e ½Senepol SC apresentaram maior GMD, GMDc e GPH que os ½Angus (P < 0,05), e Nelore apresentaram maior AOL que cruzados ½Angus e ½Senepol (P < 0,05) e maior EG que cruzados ½Senepol (P < 0,05). Cruzados ½Senepol e Nelore que receberam SC apresentaram menor emissão de CH4 por kg GM... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Exp. 1 and 2: The objective of this study was evaluated effect of nutritional plans on the performance, intake, digestibility, enteric methane emissions, ruminal fermentation, microbial efficiency synthesis and rumen microbial bacteria of young bulls of different genetic group during the growth phase on pasture. One hundred and sixty-two Nellore young bulls, crossbred ½Senepol and crossbred ½Angus, were used in a randomized complete block design, 2 × 3 factorial arrangement, average age of 10 ± 2 months and initial body weight of 262 ± 31 kg, in the experiment performance. Twelve bulls, four of each GG (Nellore, Senepol and crossbred ½Angus), cannulas in the rumen, with a mean age of 16 ± 2 months and initial body weight of 411 ± 34 kg, in the metabolism experimente. Both animals were allocated in twelve paddocks of Urochloa brizantha (A. Rich.) Stapf. cv. Xaraés, and were submitted to two plans nutrition: supplement with mineral (SM) salt 30 g / 100 kg body weight (PC) or concentrate (CS) 300 g / 100 kg of BW. In the performance experiment the PN with CS provided higher nutrient consumption and digestibility of CP and EE and higher LM area and FD (P <0.05). Crossbred ½Senepol showed higher digestibility of DM, OM and CP than Nellore and ½Angus (P < 0.05). However, Nellore and ½Senepol SC presented higher ADG, ADGc and GWH than ½Angus (P < 0.05), and Nellore had higher LM area than crossbred ½Angus and ½Senepol (P < 0.05) and higher FD than crossbred ½Senepol (P < 0.05). Howe... (Complete abstract click electronic access below) / Doutor

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The mitigation of greenhouse gas emissions and enhanced recovery of coalbed methane are benefits to sequestering carbon dioxide in coal seams. This is possible because of the affinity of coal to preferentially adsorb carbon dioxide over methane. Coalbed methane is the most significant natural gas reserve in central Appalachia and currently is economically produced in many fields in the Basin. This thesis documents research that assesses the capacity of coal seams in the Central Appalachian Basin to store carbon dioxide and verifies the assessment through a field validation test. This research allowed for the first detailed assessment of the capacity for coal seams in the Central Appalachian Basin to store carbon dioxide and enhance coalbed methane recovery. This assessment indicates that more than 1.3 billion tons of carbon dioxide can be sequestered, while increasing coalbed methane reserves by as much as 2.5 trillion cubic feet. As many of the coalbed methane fields are approaching maturity, carbon sequestration and enhanced coalbed methane recovery has the potential to add significant recoverable reserves and extend the life of these fields. As part of this research, one thousand tons of carbon dioxide was successfully injected into a coalbed methane well in Russell County, Virginia as the first carbon dioxide injection test in the Appalachian coalfields. Research from the field validation test identified important injection parameters and vital monitoring technologies that will be applicable to commercial-scale deployment. Results from the injection test and subsequently returning the well to production, confirm that fractured coal seams have the potential to sequester carbon dioxide and increase methane production. It was demonstrated through the use of perfluorocarbon tracers that there is a connection through the coal matrix between the injection well and surrounding producing gas wells. This connection is a cause for concern because it is a path for the carbon dioxide to migrate to the producing wells. The thesis concludes by presenting options for mitigating carbon dioxide breakthrough in commercial-scale injection projects. / Ph. D.

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This was a study undertaken to investigate municipal solid waste (MSW) landfill stability parameters and landfill leachate properties to determine how solid waste and leachate characteristics can be used to describe stability. The primary objective was to determine if leachate properties could be used to determine stability of the overlying refuse. All landfills studied were engineered landfill bioreactors giving insight to how leachate recirculation affects stability. This study investigated the correlation between cellulose, lignin, volatile solids, and biochemical methane production (BMP). These parameters can been used to characterize landfill stability. The BMP tests indicate that a saturated waste can produce methane. Cellulose is an indicator of landfill stability. Wastes high in cellulose content were found to have high BMP. Paper samples studied indicated gas production from high-cellulose paper was higher compared to low-cellulose samples. Lignin has been found to correlate fairly well with BMP. Increasing cellulose to lignin ratios correlate well with increasing BMP levels, further supporting the use of the BMP test to indicate solid waste stability. In the BMP test for leachate, a mixture of the standard growth medium (less 80% distilled water) and 80% v/v leachate incubated for 15 days produced the most consistent BMP results. Leachate cellulose and BMP correlated well. The chemical oxygen demand (COD) and biochemical oxygen demand (BOD) also had some correlation to BMP tests. Leachate COD was found to decrease over time in landfill bioreactors. The use of leachate rather than MSW to determine stability would be more efficient. / Master of Science

When a large area of open gob collapses suddenly, a windblast is produced that can cause considerable damage throughout the infrastructure of a mine. In a few cases, the windblast has been accompanied by ignitions of methane and/or coal dust. Analytical and numerical analyses investigated the transient behavior of the air through the small time period during which the roof is falling. This is sufficiently short to allow adiabatic compression of the air, i.e. negligible heat transfer to rock surfaces. Controlled escape of the air via interconnecting entries limits the build-up of air pressure. However, this same phenomenum causes the potential energy of the falling strata to be concentrated into a diminishing mass of air. Computer simulations predicted that the temperature of the air would increase rapidly as the roof descends, reaching values that are capable of igniting either methane or coal dust. This thesis concentrates on a series of laboratory tests involving the compression of mixtures of air, methane and coal dust under a falling weight and while allowing controlled escape of the mixture. The transient responses on pressure and temperature sensors were recorded. In addition to an analysis of those records, the thesis highlights those conditions in which ignitions occurred. / Master of Science