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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.
11

Isolation of cellulolytic enzymes using a metagenomic approach.

Kemp, Johan. January 2010 (has links)
M. Tech. Biotechnology. / Fossil fuel is a finite energy source which produces harmful by-products when used for combustion. A possible alternative is bio-fuel, preferably made from non-food cellulosic plants, such as bagasse or wood. Currently, there are some commercial enzymes which degrade cellulose, but there is room for improvement in both rate and sugar yield. The sugars derived from cellulose degradation are fermented to produce fuel-ethanol. This study utilized metagenomics to create a library containing environmental microbial DNA isolated from the rumen of cows. The aim of this study was to isolate local cellulolytic enzymes, more suited to the native environment and plant material, for potential use in the bio-fuel industry.
12

Evaluation of wood biomass utilization for the greenhouse industry in British Columbia

Chau, Jo 11 1900 (has links)
The Canadian greenhouse industry is challenged by high operating costs as the natural gas price has been increasing and fluctuating over the past few years. Natural gas is the primary energy used by the greenhouse industry to generate heat and carbon dioxide (CO₂) to enhance the crop productivity. There are concerns about the global warming effect caused by natural gas usage as it is a non-renewable energy. Therefore, the greenhouse industry is considering the use of wood biomass, mainly wood pellets and wood residue, to decrease the natural gas demand. However, the long-term economic value, the air quality emission, and the long-term resource availability are the main barriers for the industry to convert into wood biomass boiler. The main objectives of this study are, to evaluate the economic feasibility of using wood biomass for the greenhouse heating application, to analyze the associated impacts of the technical and economical changes, and to determine the optimal biomass mix with the consideration of emission limits and resources availability constraints. Specific case studies will be considered in this research to achieve the mentioned objectives. The results of the techno-economic analysis showed positive net present value (NPV) for the four cases considered: using wood pellets or wood residue boiler, with or without an electrostatic precipitator (ESP), to generate portion of heat demand for a greenhouse. Although the decision making would be affected by the price changes and the size of a greenhouse, a positive NPV was determined from a pure economic view point. Wood biomass combustion could reduce over 3,000 tonnes of CO₂ equivalent greenhouse gases annually. Sensitivity analyses indicated that wood biomass attractiveness would increase with higher natural gas prices or larger energy contributions from wood biomass. The optimization study suggests a feasible biofuels mix for the case study of a 2 ha flower greenhouse and a 7.5 ha vegetable greenhouse. The model was solved considering the inclusion of an ESP system to ensure the air quality limits were satisfied. The optimal result was compared to an existing 2 ha flower greenhouse and revealed almost 20% reduction on the total fuel cost per year.
13

Economic and energy efficiency assessment of biomass harvesting at a northern off-grid community: a case study of Barren Lands First Nation at Brochet, Manitoba, Canada.

Fennell, Kipp 12 1900 (has links)
This study was the first to analyze the cost and energy requirements to harvest and transport wood-biomass to an off-grid community, namely Brochet, Manitoba, for the purpose of bioenergy. The study takes the unique local conditions and circumstances of a remote northern off-grid community into consideration, including: marginal forest resources and transport over winter road networks. Analysis of the forest resources within the study area using various resources found that the wood supply for a biomass facility was adequate. Under most conditions, the combined cost to harvest and transport biomass to Brochet using a variety of systems was less expensive than the combined purchase and transport cost of diesel fuel. The analysis also found that significant employment opportunities and a reduction in carbon emissions would be realized through wood biomass production.
14

Economic and energy efficiency assessment of biomass harvesting at a northern off-grid community: a case study of Barren Lands First Nation at Brochet, Manitoba, Canada.

Fennell, Kipp 12 1900 (has links)
This study was the first to analyze the cost and energy requirements to harvest and transport wood-biomass to an off-grid community, namely Brochet, Manitoba, for the purpose of bioenergy. The study takes the unique local conditions and circumstances of a remote northern off-grid community into consideration, including: marginal forest resources and transport over winter road networks. Analysis of the forest resources within the study area using various resources found that the wood supply for a biomass facility was adequate. Under most conditions, the combined cost to harvest and transport biomass to Brochet using a variety of systems was less expensive than the combined purchase and transport cost of diesel fuel. The analysis also found that significant employment opportunities and a reduction in carbon emissions would be realized through wood biomass production.
15

Ignition behavior and air delivery requirements observed during the carbonization of pressurized packed beds of biomass

Wade, Samuel R January 2005 (has links)
Thesis (M.S.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 99-105). / xvi, 105 leaves, bound ill. 29 cm
16

Evaluation of wood biomass utilization for the greenhouse industry in British Columbia

Chau, Jo 11 1900 (has links)
The Canadian greenhouse industry is challenged by high operating costs as the natural gas price has been increasing and fluctuating over the past few years. Natural gas is the primary energy used by the greenhouse industry to generate heat and carbon dioxide (CO₂) to enhance the crop productivity. There are concerns about the global warming effect caused by natural gas usage as it is a non-renewable energy. Therefore, the greenhouse industry is considering the use of wood biomass, mainly wood pellets and wood residue, to decrease the natural gas demand. However, the long-term economic value, the air quality emission, and the long-term resource availability are the main barriers for the industry to convert into wood biomass boiler. The main objectives of this study are, to evaluate the economic feasibility of using wood biomass for the greenhouse heating application, to analyze the associated impacts of the technical and economical changes, and to determine the optimal biomass mix with the consideration of emission limits and resources availability constraints. Specific case studies will be considered in this research to achieve the mentioned objectives. The results of the techno-economic analysis showed positive net present value (NPV) for the four cases considered: using wood pellets or wood residue boiler, with or without an electrostatic precipitator (ESP), to generate portion of heat demand for a greenhouse. Although the decision making would be affected by the price changes and the size of a greenhouse, a positive NPV was determined from a pure economic view point. Wood biomass combustion could reduce over 3,000 tonnes of CO₂ equivalent greenhouse gases annually. Sensitivity analyses indicated that wood biomass attractiveness would increase with higher natural gas prices or larger energy contributions from wood biomass. The optimization study suggests a feasible biofuels mix for the case study of a 2 ha flower greenhouse and a 7.5 ha vegetable greenhouse. The model was solved considering the inclusion of an ESP system to ensure the air quality limits were satisfied. The optimal result was compared to an existing 2 ha flower greenhouse and revealed almost 20% reduction on the total fuel cost per year.
17

Estimating regional supply and delivered cost of forest and wood processing biomass available for bioenergy : a thesis submitted in partial fulfilment of the requirements for the degree of Masters in [i.e. Master of] Forestry Science in the University of Canterbury /

Robertson, Kimberly. January 2006 (has links)
Thesis (M. For. Sc.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references (leaves 80-82). Also available via the World Wide Web.
18

On-line measurement of active biomass

Martin, Sarah Rebecca January 2002 (has links)
A novel prototype instrument was developed to measure biomass catalase activity of suspended cultures. The technology was applied to develop a batch method of measuring activity in other media (e.g. soils) and a method of measuring hydrogen peroxide concentration. The biomass catalase activity of different microbial populations was measured successfully semi-continuously on-line (activated sludge, nitrifying culture) and off-line (soils). Garden soil, soil undergoing bioremediation and a characterised soil demonstrated catalase activities between 78 and 696 catalase units g" 1 dry weight of soil. Catalase activity was linearly correlated with different weights of each soil and was an indicator of bioremediation efficiency. Nitrifying cultures (enrichment nitrifying culture and pure cultures of Nitrosomonas) were shown to have a specific activity between 79,012 and 265,965 catalase units g" 1 MLVSS. Nitrification ability of the cultures was inhibited by ATU and 3,5-DCP while catalase activity remained stable for more than one hour following inhibitor addition in continuous studies. Activated sludges taken from Cynon Sewage Treatment Works then maintained in the laboratory were shown to have a specific activity between 8,392 and 107,136 catalase units g^MLVSS. Using a 100 litre activated sludge plant operating at varying OLR (between 0.5 and 2.0 kg COD m"3 reactor day" 1 , corresponding to changes in F/M of between 0.12 and 0.65 kg COD/kg MLVSS day" 1 ) in 8 experiments lasting up to 15 days, an increase in organic loading rate was reflected by an increase in catalase activity and increased utilisation of dissolved oxygen. Starvation caused by a decrease in OLR also increased catalase activity by up to seven times within 36 hours. The catalase activity monitor provides additional knowledge of the effects of environmental changes on biological processes occurring within a wastewater treatment plant that may not be reflected by current standard methods alone.
19

Evaluation of wood biomass utilization for the greenhouse industry in British Columbia

Chau, Jo 11 1900 (has links)
The Canadian greenhouse industry is challenged by high operating costs as the natural gas price has been increasing and fluctuating over the past few years. Natural gas is the primary energy used by the greenhouse industry to generate heat and carbon dioxide (CO₂) to enhance the crop productivity. There are concerns about the global warming effect caused by natural gas usage as it is a non-renewable energy. Therefore, the greenhouse industry is considering the use of wood biomass, mainly wood pellets and wood residue, to decrease the natural gas demand. However, the long-term economic value, the air quality emission, and the long-term resource availability are the main barriers for the industry to convert into wood biomass boiler. The main objectives of this study are, to evaluate the economic feasibility of using wood biomass for the greenhouse heating application, to analyze the associated impacts of the technical and economical changes, and to determine the optimal biomass mix with the consideration of emission limits and resources availability constraints. Specific case studies will be considered in this research to achieve the mentioned objectives. The results of the techno-economic analysis showed positive net present value (NPV) for the four cases considered: using wood pellets or wood residue boiler, with or without an electrostatic precipitator (ESP), to generate portion of heat demand for a greenhouse. Although the decision making would be affected by the price changes and the size of a greenhouse, a positive NPV was determined from a pure economic view point. Wood biomass combustion could reduce over 3,000 tonnes of CO₂ equivalent greenhouse gases annually. Sensitivity analyses indicated that wood biomass attractiveness would increase with higher natural gas prices or larger energy contributions from wood biomass. The optimization study suggests a feasible biofuels mix for the case study of a 2 ha flower greenhouse and a 7.5 ha vegetable greenhouse. The model was solved considering the inclusion of an ESP system to ensure the air quality limits were satisfied. The optimal result was compared to an existing 2 ha flower greenhouse and revealed almost 20% reduction on the total fuel cost per year. / Forestry, Faculty of / Graduate
20

Reaction Engineering Implications of Using Water for the Conversion of Lignocellulosic Biomass

Tyufekchiev, Maksim V 03 December 2019 (has links)
Conversion of lignocellulosic biomass via hydrolysis of cellulose to simple sugars has failed to achieve economic competitiveness to produce renewable fuels and chemicals partly due to the inherent recalcitrance of the substrate and partly due to the use of non-recyclable catalysts. Solid acids have been proposed for cellulose hydrolysis as a recyclable alternative to enzymes and homogeneous acids. However, their catalytic mechanism has not been elucidated partly due to incomplete structural characterization. We focused on elucidating the structure of chloromethyl polystyrene based catalysts which exhibit remarkable activity towards hydrolyzing cellulose. By carrying out spatially resolved analysis of CMP-SO3H-0.3, a catalyst decorated with benzyl chloride and benzyl sulfonic acid groups, we discovered that the external surface of the catalyst is devoid of any chloride groups, which were hypothesized to interact with cellulose. Despite apparent greater reactivity than sulfonated-only catalysts, we found the CMP-SO3H-0.3 reacts with water at the reaction conditions used for cellulose hydrolysis, resulting in leaching of homogeneous hydrochloric acid, which in turn is responsible for the observed cellulose hydrolysis. Building on these results we investigated whether catalysts from various structural classes are stable in the hydrothermal environment or leach homogeneous acid. Surprisingly, we discovered that materials commonly used for cellulose hydrolysis are hydrothermally unstable and the leached homogeneous acid they produced was responsible for their apparent catalytic activity. On the other hand, hydrothermally stable materials did not exhibit greater hydrolysis activity than water. Cellulose crystallinity has been theorized for decades as a structural parameter determining the reactivity of cellulose, which motivated decrystallization pretreatment processes. However, water-induced recrystallization had not been accounted for in hydrolysis models, albeit being a well-documented phenomenon, and all hydrolysis processes use water as a reaction medium. By carrying out detailed structure-reactivity analysis we concluded that decrystallized cellulose undergoes a rapid transformation to an active crystalline cellulose, characterized by allomorphs I and II and greater content of surface polymer chains. Water-induced recrystallization reduced the reactivity of cellulose and prevented conversion of highly reactive amorphous regions. To circumvent the recrystallization pathway, we used ethanolysis as a means for rapid and selective depolymerization of amorphous cellulose. Ethanolysis of ball-milled cellulose for 30 minutes at 410 K resulted in 38% conversion, while hydrolysis at the same conditions in only 15%. Scission-relaxation caused recrystallization and limited conversion via ethanolysis. By using co-solvents capable of swelling cellulose, we were able to increase cellulose conversion to 48%. The results presented in those studies can guide future development of catalysts and depolymerization processes that circumvent the inhibiting effects caused by the use of water.

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