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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.
21

The Effects of Nitrogen Fertilization on Bioenergy Sorghum Yield and Quality

Zilahi-Sebess, Szilvia 2012 May 1900 (has links)
Forage sorghum (Sorghum bicolor L. Moench) is one of the prospective crops that may be used to produce biofuels in the future. Therefore, it is of interest to find management practices that improve both the production of biomass yield and quality. This study presents observations of the effects different rates of nitrogen fertilization have on yield, tissue nitrogen content, and tissue quality measures such as ash, lignin, sucrose, xylans, cellulose and starch content, based on three years of field trials from the Brazos Bottom and one year of field trials from near China, Texas. Data for the quality components were obtained using near infrared spectroscopy, with the exception of tissue nitrogen which was determined by using the dry combustion method. This study has showed fertilizer nitrogen had a strong positive correlation with the tissue nitrogen of sorghum biomass. Changes in tissue quality in relationship with fertilizer nitrogen levels and tissue nitrogen concentration were also observed. Ash showed a strong positive and sucrose showed a strong negative correlation to both tissue nitrogen concentration and fertilizer nitrogen application. Similarly to sucrose, starch also decreased with higher nitrogen levels and lignin was found to increase slightly. The concentration of cellulose and xylans were very weakly affected by nitrogen application and nitrogen concentration.
22

Silica supported palladium nanoparticles for the decarboxylation of high-acid feedstocks: design, deactivation and regeneration

Ping, Eric Wayne 29 March 2011 (has links)
The major goals of this thesis were to (1) design and synthesize a supported catalyst with well-defined monodisperse palladium nanoparticles evenly distributed throughout an inorganic oxide substrate with tunable porosity characteristics, (2) demonstrate the catalytic activity of this material in the decarboxylation of long chain fatty acids and their derivatives to make diesel-length hydrocarbons, (3) elucidate the deactivation mechanism of supported palladium catalysts under decarboxylation conditions via post mortem catalyst characterization and develop a regeneration methodology thereupon, and (4) apply this catalytic system to a real low-value biofeedstock. In an effort to maximize loading and minimize mass transfer limitations, mesoporous silica MCF was synthesized as catalyst support. Functionalization with various silane ligands facilitated even distribution of palladium precursor salts throughout the catalyst particle, and, after reduction, monodisperse palladium nanoparticles approximately 2 nm in diameter. The Pd-MCF catalyst showed high one-time activity in the decarboxylation of fatty acids to hydrocarbons in dodecane at 300 °C. Subsequent reactions were performed on acid derivatives to elucidate a decarboxylation reaction pathway. The catalyst experienced severe deactivation after only one use and substantial effort was put into elucidating the nature of this deactivation via post mortem catalyst characterization. The deactivation was found not to be caused by nanoparticle sintering, agglomeration or ripening, but instead by organic deposition, mainly of reactant acid. A regeneration methodology was developed and subsequent catalyst reuse exhibited high activity. Finally, the Pd-MCF catalyst was applied to a wastewater-derived brown grease from a poultry rendering facility, in an unpolished and polished form. The latter was successfully decarboxylated to diesel-length hydrocarbons with high conversion and selectivity.
23

A Study on the Technical and Economic Feasibility for Arable Agriculture and Biofuel Production on Landfill Covers in Southern Ontario

Battiston, Lee Anthony 14 February 2013 (has links)
There are over 3,700 active and decommissioned municipal solid waste (MSW) landfill sites located in Ontario (MOE, 1991). Under current legislation, these landfill sites must be rehabilitated to a defined end use when decommissioned. In Ontario, the primary prescribed end use of closed landfills is typically agriculture, and that end use can lead to food-consumer concerns, due to the perceived risk of potential contamination from legacy materials found in landfills. Converting these sites to produce biomass-energy crops instead of food crops could mitigate that concern and also help to avoid the current controversy with bioenergy-crop production on high-capability agricultural land. In this study, a 3.5-year field program with subsequent verification and analysis investigated and developed rehabilitation prescriptions using locally obtained topsoil and soil-forming materials (subsoil) to develop anthropogenic soil profiles on top of a sealed landfill cover (clay cap). These prescriptions provided crop productivity at least as good as, and generally better than, local agricultural soils. Mixed forages and biomass-specific crops (warm season grasses) were grown on these soils in replicated plot trials to evaluate the efficacy of a range of soil treatments. Following establishment of technical feasibility for site rehabilitation, economic modeling was conducted to determine the feasibility of using these anthropogenic soils for the production of forage crops, biofuel feedstock, and simple energy products at a scale consistent with typical landfill sites in Ontario. An economic model was developed to aid proponents in selecting appropriate rehabilitation methods and to assess potential bioenergy-crop outputs for their site. This study demonstrated that while it is technically feasible to rehabilitate these waste sites to produce agricultural crops and/or biofuel feedstock, the scale of typical landfill sites makes it very difficult to compete, from an economic perspective, with conventional energy sources. However, the diverted incoming materials, such as leaf and yard waste, compostable biosolids, and paper mill waste, can be used in the development of manufactured soil profiles for rehabilitation, significantly reducing rehabilitation costs and facilitating more cost-competitive production of agricultural and biomass feedstock crops. / Niagara Waste Systems Limited, a division of Walker Industries Holdings Limited, MITACS
24

Green biomass: characterization and fractionation of immature cereal crops

Brenner, Carla Unknown Date
No description available.
25

The Production of a Potential Feedstock for Biodiesel using Water and Isopropyl Alcohol to Extract Yellow Mustard Oil

Ataya Pulido, Veronica Maria 21 July 2010 (has links)
The aim of this project was to produce a potential feedstock for biodiesel by developing a process to extract oil from yellow mustard seeds using aqueous and isopropyl alcohol extraction. The aqueous extraction of yellow mustard flour was performed at pH 11 using 4:1 water to flour ratio and constant stirring at room temperature for 30min, with a second washing stage. Oil was separated as oil-in-water emulsion with 37% oil recovery from the flour. The oil in the emulsion was then extracted with isopropyl alcohol. Single and multiple stage extractions were evaluated and the optimal conditions were four-stage extraction at 2:1 IPA:Oil weight ratio, with 96.3% oil recovery from the emulsion. A preliminary evaluation of the final solution of isopropyl alcohol, water and yellow mustard oil concluded that it is indeed a potential feedstock for biodiesel, however it needs to be further processed to meet optimal conditions for transesterification.
26

The Production of a Potential Feedstock for Biodiesel using Water and Isopropyl Alcohol to Extract Yellow Mustard Oil

Ataya Pulido, Veronica Maria 21 July 2010 (has links)
The aim of this project was to produce a potential feedstock for biodiesel by developing a process to extract oil from yellow mustard seeds using aqueous and isopropyl alcohol extraction. The aqueous extraction of yellow mustard flour was performed at pH 11 using 4:1 water to flour ratio and constant stirring at room temperature for 30min, with a second washing stage. Oil was separated as oil-in-water emulsion with 37% oil recovery from the flour. The oil in the emulsion was then extracted with isopropyl alcohol. Single and multiple stage extractions were evaluated and the optimal conditions were four-stage extraction at 2:1 IPA:Oil weight ratio, with 96.3% oil recovery from the emulsion. A preliminary evaluation of the final solution of isopropyl alcohol, water and yellow mustard oil concluded that it is indeed a potential feedstock for biodiesel, however it needs to be further processed to meet optimal conditions for transesterification.
27

Green biomass: characterization and fractionation of immature cereal crops

Brenner, Carla 11 1900 (has links)
The development of a biorefining process acknowledges the feedstock characterization as it can often dictate the process technology. The maturity stages of agricultural feedstocks also have the potential for altering the process conditions. Thus, the variability of growth stages at 4-6 leaf, flowering, milk and soft dough were assessed for use of immature cereal crops in a green biomass biorefinery. Hence, the primary objective of this project was to evaluate the composition of green biomass at different harvest stages. Four varieties of triticale, two wheat varieties and two rye varieties were analyzed for starch, protein, phenols, fatty acids and sterols. To further characterize the feedstocks, an alternate extraction strategy was explored based on solvent polarity. It was found that for triticale varieties, the milk to soft dough harvest stages showed a decrease in proteins and phenols content and an increase in starch content. This could potentially provide benefit to organic acid production through fermentation. / Bioresource and Food Engineering
28

Three Essays on Climate Change Impacts, Adaptation and Mitigation in Agriculture

Wang, Wei Wei 2012 August 1900 (has links)
This dissertation investigates three economic aspects of the climate change issue: optimal allocation of investment between adaptation and mitigation, impacts on a ground water dependent regional agricultural economy and effects on global food insecurity. This is done in three essays by applying mathematical programming. In the first essay, a modeling study is done on optimal temporal investment between climate change adaptation and mitigation considering their relative contributions to damage reduction and diversion of funds from consumption and other investments. To conduct this research, we extend the widely used Integrated Assessment Model?DICE (Dynamic Integrated Climate Economy) adding improved adaptation modeling. The model results suggest that the joint implementation of adaptation and mitigation is welfare improving with a greater immediate role for adaptation. In the second essay, the research focuses on the ground water dependent agricultural economy in the Texas High Plains Region. A regionally detailed dynamic land allocation model is developed and applied for studying interrelationships between limited natural resources (e.g. land and groundwater), climate change, bioenergy demands and agricultural production. We find out that the effect varies regionally across hydrologically heterogeneous regions. Also, water availability has a substantial impact on feedstock mix. In terms of biofuel feedstock production, the model results show that limited water resource cannot sustain expanded corn-based ethanol production in the future. In the third essay, a Computable General Equilibrium (CGE) model is applied in an attempt to study potential impacts of climate change on global food insecurity. Our results show that climate change alters the number of food insecure people in a regionally different fashion over time. In general, the largest increase of additional food insecure population relative to the reference case (no climate change) is found in Africa and South Asia, while most of developed countries will benefit from climate change with a reduced proportion of food insecure population. In general, climate change affects world agricultural production and food security. Integrated adaptation and mitigation strategy is more effective in reducing climate change damages. However, there are synergies/trade-offs between these two options, particularly in regions with limited natural resources.
29

Desenvolvimento de sistema ligante para processamento de alumina por injeção a partir de polímeros de fontes renováveis

Mota, Eliane Neves da January 2014 (has links)
Neste trabalho, inicialmente, foram obtidos TPSs (amidos termoplásticos) com diferentes concentrações de amido e plastificantes, por processamento em câmara de mistura, com o objetivo de determinar formulações para estudo em extrusora reativa. As formulações de TPS que apresentaram os melhores resultados de torque reométrico foram as que continham 39%m/m de amido. Investigou-se a influência da velocidade da rosca na obtenção de TPS por extrusora reativa, e os resultados mostraram que este parâmetro teve pequena influência na estabilidade do amido termoplástico, sendo possível utilizar 150 rpm de rotação. Foram produzidas 5 blendas com razões de TPS:PEBDL variando de 30:70; 40:60; 50;50; 60:40 e 70:30 para o desenvolvimento de um sistema ligante para a injeção de alumina pelo processo de moldagem de pós (MPI), a partir das quais foi possível analisar a influência do TPS no PEBDL, através de análises de MEV, IF, TGA, DMA e propriedades mecânicas. Quanto maior a concentração de TPS nas blendas, mais heterogênea foi a morfologia observada por MEV e menor o módulo de armazenamento e de perda obtidos por DMA. Este comportamento foi similar ao encontrado pela análise de resistência à tração, que apresentou propriedades mecânicas pobres para elevadas concentrações de TPS. Foram escolhidas três blendas para testar como veículo orgânico em feedstocks de alumina, com carga de partícula sólida de 45%, 50% e 55%v/v de Al2O3. A carga crítica para o sistema ligante-partículas sólidas determinada por reometria de torque foi de 50%v/v de alumina. / In this work, TPSs (thermoplastic starch), with different concentrations of starch and plasticizers for processing in the mixing chamber, were obtained in order to determine formulations for study in a reactive extruder. The TPS formulations that showed the best results for the rheometric torque were those containing 39% w/w starch. The influence of the screw speed to obtain TPS in the reactive extruder was investigated and the results showed that this parameter had little influence on the stability of the thermoplastic starch, allowing the use of 150 rpm rotation speed. Five blends were produced, with TPS:LLDPE ratios of 30:70; 40:60; 50:50; 60:40 and 70:30, to develop a binder for alumina injection by the powder molding process (MPI). From these five systems it was possible to analyze the influence of TPS in LLDPE through SEM analyzes, MFI, TGA, DMA and mechanical properties. The higher the concentration of TPS in blends, more heterogeneous morphology was observed by SEM and the lowest storage and loss modulus were obtained by DMA. This behavior was similar to that found by analysis of tensile strength, which showed poor mechanical properties for high concentrations of TPS. Three blends were chosen for testing as an organic vehicle in alumina feedstocks, with solid particles load of 45%, 50% and 55% v/v of Al2O3. The critical load for the system binder-solid particles, determined by torque rheometry, was 50% v/v of alumina.
30

Efeito da clarificação na microbiota e qualidade da cachaça orgânica /

Teixeira, Vitor. January 2016 (has links)
Orientador: Marcia Justino Rossini Mutton / Banca: Everlon Cid Rigobelo / Banca: Francisco Vicente Gaiotto Cleto / Resumo: Na produção de cachaça, a presença de micro-organismos contaminantes é prejudicial à qualidade da bebida, estes deterioram os colmos e metabolizam os açúcares presentes para a produção de compostos indesejáveis. O objetivo do trabalho foi avaliar a ação da clarificação do caldo e a utilização do extrato de sementes de moringa na redução de micro-organismos contaminantes da fermentação alcoólica e a atividade antimicrobiana do extrato sobre duas matérias-primas diferentes, recém-processada e colmos armazenados por 24h, além dos reflexos dos componentes e caracterização das cachaças. O delineamento experimental foi realizado em parcelas subdivididas com três repetições, empregando-se 3 tratamentos principais: Caldo "in natura", caldo caleado e caldo caleado com extrato de semente de moringa como floculante. Os tratamentos secundários foram constituídos por colmos recém-colhidos e armazenados por 24 horas. Foram realizadas análises físico-quimicas e microbiológicas ao longo do processo de produção, além de análises dos componentes e caracterização das cachaças. A utilização do extrato de semente de moringa na clarificação do caldo resulta em redução significativa de 41,66% na microbiota total do caldo extraído. A matéria-prima não armazenada apresentou menor quantidade de bactérias lácticas e leveduras presente no processo fermentativo. As concentrações dos coeficientes de congêneres diminuiram 5,27% empregando-se o processo de caleagem e 10% com o uso do extrato de sementes de ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the production of cachaça, the presence of contaminating microorganisms is detrimental to the quality of the beverage, they deteriorate the stalks and metabolize the sugars present for the production of undesirable compounds. The objective of this work was to evaluate the action of broth clarification and the use of the moringa seed extract in the reduction of microorganisms contaminating the alcoholic fermentation and the antimicrobial activity of the extract on two different raw materials, freshly processed and stored stems For 24 hours, besides the component reflexes and characterization of the cachaças. The experimental design was carried out in subdivided plots with three replicates, using 3 main treatments: "In natura" broth, calyx broth and calyx broth with moringa seed extract as flocculant. Secondary treatments consisted of freshly harvested stalks and stored for 24 hours. Physicochemical and microbiological analyzes were carried out throughout the production process, as well as component analysis and characterization of cachaças. The use of the moringa seed extract in broth clarification results in a significant reduction of 41.66% in the total microbiota of the extracted broth. The non-stored raw material showed less lactic acid bacteria and yeast present in the fermentation process. The concentrations of the congeners coefficients decreased 5.27% using the chalking process and 10% with the use of the moringa seed extract as natural flocculant in both raw materials. The reduction of the compounds is due to the lower formation of the higher alcohols in the cachaças. It is concluded that the Moringa oleifera Lamarck seed extract presents antimicrobial activity on the total microbiota of the raw material, reduction of lactic bacteria during the fermentation process and lower formation of higher alcohols in the cachaça. The ... (Complete abstract click electronic access below) / Mestre

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