Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Candidate: Veronika Skalická Supervisor: Dr. Georgios Paraskevopoulos, Ph.D.; Michael Binnefeld Title of Diploma thesis: Up-scaling and further development of matrix liposomes The thesis evaluates novel matrix liposomes formed by dual asymmetric centrifugation technology. Particles' parameters (size, size distribution and ζ-potential) were analyzed by dynamic light scattering method using ZetaSizer device. Encapsulation efficacy was determined by size exclusion chromatography using carboxyfluorescein as fluorescent encapsulation marker. The overall results support that the most beneficial formulation parameters are 15 min of speed mixing process with ceramic beads of diameter 1,0-1,2 mm. Up-scaling of the procedure didn't drastically affect liposomal parameters up to a lipid batch load of 700 mg. Furthermore, the usage of different types of gelatin or glycerinated gelatin didn't significantly influenced particles' characteristics. It is noteworthy that the matrix composed of 50% glycerinated gel sustained the ability to form liposomes by dispersion of vesicular phospholipid gels in phosphate buffer saline even after 31 days. Other matrices showed a damage of liposomes as confirmed by size and size...

Indiana University-Purdue University Indianapolis (IUPUI) / Natural gas substitution for diesel can result in significant reduction in pollutant emissions. Based on current fuel price projections, operating costs would be lower. With a high ignition temperature and relatively low reactivity, natural gas can enable promising approaches to combustion engine design. In particular, the combination of low reactivity natural gas and high reactivity diesel may allow for optimal operation as a reactivity-controlled compression ignition (RCCI) engine, which has potential for high efficiency and low emissions. In this computational study, a lean mixture of natural gas is ignited by direct injection of diesel fuel in a model of the heavy-duty CAT3401 diesel engine. Dual-fuel combustion of natural gas-diesel (NGD) may provide a wider range of reactivity control than other dual-fuel combustion strategies such as gasoline-diesel dual fuel. Accurate and efficient combustion modeling can aid NGD dual-fuel engine control and optimization. In this study, multi-dimensional simulation was performed using a nite-volume computational code for fuel spray, combustion and emission processes. Adaptive mesh refinement (AMR) and multi-zone reaction modeling enables simulation in a reasonable time. The latter approach avoids expensive kinetic calculations in every computational cell, with considerable speedup. Two approaches to combustion modeling are used within the Reynolds averaged Navier-Stokes (RANS) framework. The first approach uses direct integration of the detailed chemistry and no turbulence-chemistry interaction modeling. The model produces encouraging agreement between the simulation and experimental data. For reasonable accuracy and computation cost, a minimum cell size of 0.2 millimeters is suggested for NGD dual-fuel engine combustion. In addition, the role of different chemical reaction mechanism on the NGD dual-fuel combustion is considered with this model. This work considers fundamental questions regarding combustion in NGD dual-fuel combustion, particularly about how and where fuels react, and the difference between combustion in the dual fuel mode and conventional diesel mode. The results show that in part-load working condition main part of CH4 cannot burn and it has significant effect in high level of HC emission in NGD dual-fuel engine. The CFD results reveal that homogeneous mixture of CH4 and air is too lean, and it cannot ignite in regions that any species from C7H16 chemical mechanism does not exist. It is shown that multi-injection of diesel fuel with an early main injection can reduce HC emission significantly in the NGD dual-fuel engine. In addition, the results reveal that increasing the air fuel ratio by decreasing the air amount could be a promising idea for HC emission reduction in NGD dual-fuel engine, too.

We look at some inventory models for dual channel retailers who fulfill demands from both channels from the same pool of stock. Since the arrival of the internet, companies, particularly retailers, have been trying to figure out how best to take advantage of this new channel. This became acute for retailers when Amazon.com became the pre-dominant bookseller overcoming rivals like Barnes and Noble and Borders who had been operating for several decades. Firms in other categories were worried that a web only retailer like Amazon.com could end up dominating their sectors as well. To respond to such threats, existing retailers like Tesco and Lands End began offering their products through a web-site which became their web channel. To improve efficiency and to take advantage of specific characteristics of this channel, firms had to modify the operations of their existing channels. In this thesis, we look at retailers who took advantage of the web channel to better their operations for the entire firm. / Thesis / Doctor of Business Administration (DBA)

No description available.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Supervisor: Supervisor: Diana M. DiNitto. Vita. Includes bibliographical references. Also available from UMI.

Thesis (M.S.W.)--University of Hong Kong, 1994. / Includes bibliographical references (leaves 68-70).

Thesis (M.S.W.)--University of Hong Kong, 1994. / Includes bibliographical references.

Thesis (M.S.W.)--University of Hong Kong, 1994. / Includes bibliographical references (leaves 68-70). Also available in print.

Le développement de stratégies de combustion innovantes est nécessaire aujourd’hui pour répondre aux réglementations de plus en plus intransigeantes qui fixent les seuils d’émissions polluantes par les véhicules neufs. Parmi ces stratégies, l’approche Dual Fuel a montré un fort potentiel dans la réduction des émissions tout en maintenant des niveaux de rendement élevés. Le concept Dual Fuel est fondé sur la formation d’un mélange homogène d’air et d’un carburant volatile (essence, méthane, éthanol...) allumé par une injection directe d’un carburant à fort cétane (de type gazole) dans la chambre de combustion. Une compréhension détaillée des différents processus de combustion est primordiale pour aider au développement des stratégies Dual Fuel concrètes. Dans ce contexte, le développement d’un modèle adapté, couplé à des mesures expérimentales réalisées sur moteur optique, est indispensable pour optimiser la combustion Dual Fuel. Une étude numérique, fondée sur le couplage d’un modèle de combustion turbulente dédié à la propagation de flamme dans des milieux stratifiés (ECFM3Z) et un modèle de chimie tabulée pour la prédiction de l’auto-inflammation (TKI), a été menée afin d’évaluer la capacité des modèles existants à prédire les différents régimes de combustion qui pourraient exister dans les stratégies Dual Fuel. Des critères de transition ont été ajoutés et évalués afin d’améliorer le couplage des deux modèles et d’assurer la transition entre l’auto-inflammation et la propagation de flamme. D’autre part, l’étude expérimentale sur un moteur à accès optiques a permis d’étudier des variations de richesse, de carburant de prémélange et de taux de dilution et de caractériser de manière fine les mécanismes de la combustion Dual Fuel afin de servir de base de données aux développements de modèles CFD. / Advanced combustion strategies are required in response to increasingly stringent worldwide regulations governing exhaust gas emissions in the transport sector. Among these strategies, the Dual Fuel approach has shown potential to reduce engine-out pollutant emissions without penalizing combustion efficiency. The Dual Fuel concept relies on the formation of a homogeneous mixture of air with a highly volatile fuel (gasoline, methane, ethanol...) which is ignited by direct injection of a high-cetane fuel (Diesel fuel) in the combustion chamber. An improved understanding of the underlying physical phenomena and a detailed insight of the predominant combustion regime(s) are required in order to advance the development of the Dual Fuel combustion strategies. In this context, numerical modeling and optical engine measurements are combined to investigate Dual Fuel combustion. A numerical study, based on the coupling between a turbulent combustion model for flame propagation in stratified mixtures (ECFM3Z) and a tabulated kinetics model for auto-ignition (TKI), was conducted to evaluate the capacity of the existing models to cope with the various combustion regimes that might exist in Duel Fuel combustion strategies. Transition criteria were added and evaluated in order to improve the coupling between the two models and to better predict the transitions between auto-ignition and flame propagation. In addition, an experimental investigation, including equivalence ratio, premixed fuel and dilution variations, was performed in an optical engine. The objective was to apply advanced optical diagnostic techniques to thoroughly characterize the Dual Fuel combustion process and thus enhancing CFD model developments.

<p dir="ltr">The Higher Learning Commission (HLC) clarified and revised the credentialing standards for concurrent enrollment (CE) instructors of liberal arts courses in 2015 with an implementation date of 2017. With the revised credentialing standards resulting in roughly two out every three CE instructors needing additional graduate level coursework to maintain their CE credentials, HLC created a five-year grace period, followed by multiple extensions, for CE instructors to update their credentials. However, during this period only approximately half of the CE instructors completed the additional coursework. The possible loss of half of the total number of liberal arts CE instructors under HLC accreditation places many CE programs’ sustainability in jeopardy.</p><p dir="ltr">This dissertation encompasses two studies that investigated why CE instructors did or did not complete the additional coursework needed to maintain the CE credentials, a topic that has yet to be explored in research. The first study investigated the issue directly from the CE instructor perspective. The second study on the topic was approached through the lens of CE high school administrators. Principal-agent theory was the theorical framework from which data and findings were viewed and produced. Implications for the CE field, future research angles on the topic, and policy recommendations are offered.</p>