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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.
151

Web-based Calculator for Residential Energy Conservation

Gupta, Pulkit 19 January 2010 (has links)
A large Canadian financial services institution (FSI) is planning to develop a web-based application aimed at helping homeowners calculate the financial and environmental impacts of potential energy conserving upgrades to their dwellings. The algorithm for this calculator, the questions to be posed to the homeowners, and how the homeowners can access some of the scientifically-inclined energy-related information is presented. The potential upgrades considered were: furnace efficiency, heat-pump efficiency, programmable thermostats, window-efficiency, building insulation, lighting efficiency, and refrigerator efficiency. The algorithm developed was used to demonstrate that changing just one of the input variables can, in certain cases, have a drastic effect on the resulting output: upgrades with positive net present values (NPV) can drop to negative NPV, and in certain cases CO2 emissions can increase as a result of the upgrade considered. The effect of future changes in fuel prices, and the price levied on CO2 emissions is also demonstrated.
152

The Effectiveness of Magnesium Oxide-based Additives in Mitigating Fouling Problems in Kraft Recovery Boilers

Zhao, Liming 05 January 2012 (has links)
Magnesium oxide-based additives have been used in kraft recovery boilers to minimize deposit accumulation on superheater and generating bank tubes. Due to inconclusive results observed in boilers and claims made for additive effectiveness backed by little scientific evidence, only a few mills still use the additives for fouling control. A systematic study was performed to examine the effect of MgO-based additives on deposit accumulation and removal under controlled laboratory conditions, and to evaluate the additive effect in a kraft recovery boiler. The results show that while the additive coating has no effect on deposition, it could ease deposit removal if a coating greater than 5 µm can be applied on the tube surface effectively. Separate injection of additive and black liquor had insignificant effect on deposition and removal. Results of the field study show that the amount of additive collected on the tube is too small to have an impact.
153

Ensemble Modeling of Cancer Metabolism

Khazaei, Tahmineh 08 December 2011 (has links)
Metabolism in cancer cells is adapted to meet the proliferative needs of these cells, with notable changes such as enhanced lactate secretion and glucose uptake rates. In this work, we use the Ensemble Modeling (EM) framework to gain insight and predict potential drug targets for tumor cells. A metabolic network consisting of 58 reactions is considered which accounts for glycolysis, the pentose phosphate pathway, lipid metabolism, amino acid metabolism, and includes allosteric regulation. Experimentally measured metabolite concentrations are used for developing the ensemble of models along with information on established drug targets. The resulting models predicted transaldolase (TALA) and succinate-CoA ligase (SUCOAS1m) to display a significant reduction in growth rate when repressed relative to currently known drug targets. Furthermore, the synergetic repression of transaldolase and glycine hydroxymethyltransferase (GHMT2r) showed a three fold decrease in growth rate compared to the repression of single enzyme targets.
154

Life Cycle Modelling of Multi-product Lignocellulosic Ethanol Systems

Shen, Timothy 16 August 2012 (has links)
Life cycle assessment is an important tool to evaluate the impact of 2nd generation lignocellulosic ethanol, and its potential greenhouse gas (GHG) emissions benefits relative to gasoline. The choice of feedstock, process technology, and co-products may affect GHG emissions and energy metrics. Co-products may improve both the financial and environmental performance of the biorefinery. 26 well-to-wheel models of future lignocellulose-to-ethanol pathways were constructed, considering corn stover, switchgrass, and poplar feedstocks, three pre-treatment technologies, four co-product options, and the use of ethanol in a light-duty vehicle. Model results showed that all pathways with lignin pellet co-production had significantly lower net GHG emissions relative to gasoline and corresponding pathways producing only electricity. Pathways co-producing xylitol had at least 66% greater GHG emission reductions relative to pathways co-producing only lignin pellets. All feedstock/pretreatment/co-product combinations led to GHG reductions of at least 60%, meeting the threshold stipulated under the Energy Independence and Security Act.
155

Hyaluronan-methylcellulose Hydrogels for Cell and Drug Delivery to the Injured Central Nervous System

Caicco, Matthew 21 November 2012 (has links)
Spinal cord injury and stroke are two devastating neurological events that lack effective clinical treatments. Recent neuroregenerative approaches involving the delivery of cells or drugs to the injured tissue have shown promise, but face critical challenges to clinical translation. Herein, hyaluronan-methylcellulose (HAMC) hydrogels were investigated as a versatile means of overcoming the challenges facing central nervous system cell and drug delivery. HAMC was shown to support the viability of encapsulated human umbilical tissue-derived cells, demonstrating utility as a scaffold for therapeutic cell delivery to the injured spinal cord. In a drug delivery context, release of the neuroregenerative drug cyclosporin A from the hydrogel was tunable over 2-28 days and the drug diffused to the stem cell niche in the brain and persisted for up to 24 days at a stable concentration when the HAMC-based system was implanted epi-cortically. HAMC is thus a promising tool for emerging neuroregenerative therapies.
156

A Study of Fibre-matrix Interactions in Biodegradable Kraft Pulp Fibre-reinforced Polylactic Acid Composites

Fazl, Mandana 22 November 2012 (has links)
As the plastics sector moves towards sustainable growth and development, natural fibres start to play an important role as constituents in composite materials in several industries including automotives. However, drawbacks such as fibre-matrix incompatibility and poor fibre dispersion still exist. In this thesis, Kraft pulp fibre (KF)-Polylactic Acid (PLA) composites were prepared using thermal compounding and aqueous blending to study fibre-matrix interactions. Fibre surfaces were also modified to improve fibre dispersion and water absorption properties. A biorefinery lignin was added to PLA and high density polyethylene (HDPE) as a biofiller and potential interface modifier. Aqueous blended composites showed better mechanical and dynamic mechanical performance than the thermally compounded materials. The fibre surface modification improved dispersion and material properties at higher fibre content. Furthermore, the addition of lignin to polymers resulted in improved mechanical properties in both PLA and HDPE; however, lignin failed to improve interface bonding between KF and PLA.
157

Model Based Design of a Saccharomyces cerevisiae Platform Strain with Improved Tyrosine Production Capabilities

Cautha, Sarat Chandra 21 November 2012 (has links)
Large-scale production of plant secondary metabolites is of interest because of their application in production of many valuable products. Recent advances in the area of DNA recombinant technology has made it possible to produce these valuable compounds using microbial routes. The objective of this work was, to design a platform strain of Saccharomyces cerevisiae with improved intracellular tyrosine pools using computational modeling. This engineered yeast could be used as a host for producing important plant secondary metabolites on an industrial-scale. In this study, a combination of steady-state and dynamic modeling methods were used for strain design. Initial strain design was performed using steady-state modeling, and the predictions from steady-state modeling were prioritized for experimental validation using dynamic modeling. The final strategy proposed included deletion of PDC1, ZWF1, ARO10; over-expression of ALD6, and alleviation of tyrosine feedback resistance in shikimate pathway. Initial experiments for validation of this strategy showed promising results.
158

Web-based Calculator for Residential Energy Conservation

Gupta, Pulkit 19 January 2010 (has links)
A large Canadian financial services institution (FSI) is planning to develop a web-based application aimed at helping homeowners calculate the financial and environmental impacts of potential energy conserving upgrades to their dwellings. The algorithm for this calculator, the questions to be posed to the homeowners, and how the homeowners can access some of the scientifically-inclined energy-related information is presented. The potential upgrades considered were: furnace efficiency, heat-pump efficiency, programmable thermostats, window-efficiency, building insulation, lighting efficiency, and refrigerator efficiency. The algorithm developed was used to demonstrate that changing just one of the input variables can, in certain cases, have a drastic effect on the resulting output: upgrades with positive net present values (NPV) can drop to negative NPV, and in certain cases CO2 emissions can increase as a result of the upgrade considered. The effect of future changes in fuel prices, and the price levied on CO2 emissions is also demonstrated.
159

Ensemble Modeling of Cancer Metabolism

Khazaei, Tahmineh 08 December 2011 (has links)
Metabolism in cancer cells is adapted to meet the proliferative needs of these cells, with notable changes such as enhanced lactate secretion and glucose uptake rates. In this work, we use the Ensemble Modeling (EM) framework to gain insight and predict potential drug targets for tumor cells. A metabolic network consisting of 58 reactions is considered which accounts for glycolysis, the pentose phosphate pathway, lipid metabolism, amino acid metabolism, and includes allosteric regulation. Experimentally measured metabolite concentrations are used for developing the ensemble of models along with information on established drug targets. The resulting models predicted transaldolase (TALA) and succinate-CoA ligase (SUCOAS1m) to display a significant reduction in growth rate when repressed relative to currently known drug targets. Furthermore, the synergetic repression of transaldolase and glycine hydroxymethyltransferase (GHMT2r) showed a three fold decrease in growth rate compared to the repression of single enzyme targets.
160

The Effectiveness of Magnesium Oxide-based Additives in Mitigating Fouling Problems in Kraft Recovery Boilers

Zhao, Liming 05 January 2012 (has links)
Magnesium oxide-based additives have been used in kraft recovery boilers to minimize deposit accumulation on superheater and generating bank tubes. Due to inconclusive results observed in boilers and claims made for additive effectiveness backed by little scientific evidence, only a few mills still use the additives for fouling control. A systematic study was performed to examine the effect of MgO-based additives on deposit accumulation and removal under controlled laboratory conditions, and to evaluate the additive effect in a kraft recovery boiler. The results show that while the additive coating has no effect on deposition, it could ease deposit removal if a coating greater than 5 µm can be applied on the tube surface effectively. Separate injection of additive and black liquor had insignificant effect on deposition and removal. Results of the field study show that the amount of additive collected on the tube is too small to have an impact.

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