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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.
71

Production of Solar Fuels using CO2 / Production de combustibles solaires utilisant le CO2

Marepally, Bhanu Chandra 03 April 2017 (has links)
Compte tenu du récent taux alarmant d'épuisement des réserves de combustibles fossiles et de l'augmentation drastique des niveaux de CO2 dans l'atmosphère qui a conduit au réchauffement de la planète et à des changements climatiques sévères, l'exploitation de toutes sortes d'énergies renouvelables a été la Parmi les principales priorités de la recherche Champs à travers le monde. L'une des nombreuses voies de ce genre est la réduction du CO2 aux combustibles utilisant des énergies renouvelables, plus communément appelées cellules photoélectro-catalytiques (PEC). Des essais expérimentaux sur la réduction du CO2 ont été réalisés sur différents types de catalyseurs dans les deux cellules (Conçu par un laboratoire) afin de comprendre la sélectivité, la productivité et les produits de réaction obtenus. Des essais expérimentaux ont été réalisés sur différents types de catalyseurs à la fois dans les cellules en phase gazeuse et en phase liquide pour comprendre la sélectivité, la productivité et les produits de réaction obtenus. Pour les études sur la réduction EC du CO2 en phase gazeuse, une série d'électrodes (à base de nanoparticules (NPs) de Cu, Fe, Pt et CuFe déposées sur des nanotubes de carbone ou de noir de carbone puis placées à l'interface entre une membrane Nafion et Une électrode à couche de diffusion de gaz). Les résultats démontrent le type divers de produits formés et leurs productivités. Dans des conditions sans électrolyte, la formation de produits ≥C1 tels que l'éthanol, l'acétone et l'isopropanol a été observée la plus élevée étant pour Fe et suivie de près par Pt. Pour améliorer Combustibles nets, un ensemble différent d'électrodes a été préparé sur la base de revêtements MOF de type imidazolate de type zéolitique substitué (SIM-1) (Fe-CNT, Pt-CNT et CuFe-CNT basés sur MOF) Et Pt-MOF a montré des carburants améliorés. En se reportant aux études sur la réduction EC du CO2 dans une cellule en phase liquide, un ensemble similaire d'électrodes a été prepare (NP - Cu, Fe, Pt, Ru, Co déposées sur des nanotubes de carbone ou du noir de carbone ont). Pour les conditions de phase liquide, en termes de produits C nets, les électrodes catalytiques à base de Pt sont en tête de la catégorie, suivies de près par Ru et Cu, tandis que Fe a obtenu la position la plus basse. Le mécanisme réactionnel sous-jacent probable a également été fourni. Afin d'améliorer encore les performances, on a synthétisé des NP de metal (Ru, Fe, Pt et Cu) de différentes tailles en utilisant différentes techniques de synthèse: (i) l'itinéraire d'imprégnation (ImR) pour obtenir des NP dans la plage de tailles de 10 à 50 nm; (Ii) Approche organométallique (OM) pour synthétiser des NPs uniformes et ultrafines dans la plage de tailles de 1-5 nm. Fe ont été synthétisés par une nouvelle voie de synthèse et des conditions pour atteindre des NP de 1 à 3 nm. (Iii) Approche de haut en bas de Nanowire pour obtenir des NP de cuivre ultrafin dans la plage de taille de 2-3,8 nm. Les améliorations apportées à la productivité du carburant se sont révélées être de 5 à 30 fois plus élevées pour les petites NP sur les NP plus importantes et, en outre, une charge réduite de 10 à 1-2% en poids. Un autre ensemble d'électrodes à base de nano-mousses (Cu NF et Fe NF sur Feuille de Cu, Feuille de Foie, Al Foil, Inconel foil et Al grid / mesh) préparés par électrodéposition ont également été étudiés afin d'améliorer encore la conversion de CO2 / carburant. Après, l'optimisation du dépôt et de la tension à l'aide de la voltamétrie cyclique, les carburants se sont améliorés de 2 à 10 fois par rapport aux combustibles nets les plus élevés obtenus à l'aide d'électrodes CNT dopées à base de NP / In view of the recent alarming rate of depletion of fossil fuel reserves and the drastic rise in the CO2 levels in the atmosphere leading to global warming and severe climate changes, tapping into all kinds of renewable energy sources has been among the top priorities in the research fields across the globe. One of the many such pathways is CO2 reduction to fuels using renewable energies, more commonly referred as photo-electro-catalytic (PEC) cells. Experimental tests were carried out on various types of catalysts in both the gas and liquid phase cells (lab-designed) to understand the different selectivity, productivity and the reaction products obtained. For the studies on the EC reduction of CO2 in gas phase cell, a series of electrodes (based on Cu, Fe, Pt and Cu/Fe metal nanoparticles – NPs - deposited on carbon nanotubes – CNTs - or carbon black and then placed at the interface between a Nafion membrane and a gas-diffusion-layer) were prepared. Under gas phase, the formation of ≥C1 products (such as ethanol, acetone and isopropanol) were observed, the highest being for Fe and closely followed by Pt, evidencing that also non-noble metals can be used as efficient catalysts under these conditions. To enhance the net fuels, a different set of electrodes were also prepared based on substituted Zeolitic Imidazolate (SIM-1) type MOF coatings (MOF-based Fe-CNTs, Pt-CNTs and Cu/Fe-CNTs) and Pt-MOF showed improved fuels. Moving to the studies on the EC reduction of CO2 in liquid phase cell, a similar set of electrodes were prepared (metal NPs of Cu, Fe, Pt, Ru and Co deposited on CNTs or carbon black). For liquid phase conditions, in terms of net C-products, catalytic electrodes based on Pt topped the class, closely followed by Ru and Cu, while Fe got the lowest position. The probable underlying reaction mechanism was also provided. In order to improve further the performances, varied sized metal NPs (Ru, Fe, Pt and Cu) have been synthesized using different techniques: (i) impregnation (ImR) route to achieve NPs in the size range of 10-50 nm; (ii) organometallic (OM) approach to synthesize uniform and ultrafine NPs in the size range of 1-5 nm (i.e., Fe NPs were synthesized through a novel synthesis route to attain 1-3 nm NPs); (iii) Nanowire (NW) top-down approach to obtain ultrafine copper metal NPs in the size range of 2-3.8 nm. The enhancements in the fuel productivity were found to be 5-30 times higher for the smaller metal NPs over the larger metal NPs and moreover, with reduced metal loading from 10 to 1-2 wt %. A different set of electrodes based on nano-foams (Cu NF and Fe NF on Cu foil, Fe foil, Al foil, Inconel foil and Al grid/mesh) prepared via electro-deposition were also investigated, to further improve CO2 to fuels conversion. After, optimization of deposition and voltage using cyclic voltammetry, the fuels improved by 2-10 times over the highest net fuels achieved using metal NPs doped CNT electrodes
72

A case study on building NPS into production line

Lai, Yung-jin 30 July 2006 (has links)
The customer's taste is with the transition with constant time ¡A space¡A as the order pours into constantly¡A what an attitude the manufacturing plant is!¡A the flexible company quick in response turn into the existence ways of enterprises in the future¡A and under facing and producing state that must be expanded¡A how to set up production line and efficient duplicating the productive attitude fast fast¡A is it reach quantity produce quality that customer want fast ¡A must is it is it waste carry on procedure transformation to reduce to come through NPS (New Production Skill ) to come. This research is mainly to visit the arrangement which refers to the theory of relevant documents to review and study through the executive inside the company¡A to understand the company understand the themes studied from the doing in the test amount factor of expanding the factory¡A set up NPS to be flat to take production line while being accurate ¡A utilize relevant step in accordance with follow ¡A make similar industry to establish NPS production line have one procedure way in accordance with following fast future.
73

The Functionalization of Epitaxial Graphene on SiC with Nanoparticles towards Biosensing Capabilities

Strandqvist, Carl January 2015 (has links)
Graphene has been shown to be very powerful as a transducer in many biosensor applications due to its high sensitivity. This enables smaller surfaces and therefore less material consumption when producing sensors and concequently cheaper and more portable sensors compared to the commercially available sensors today. The electrical properties of graphene are very sensitive to gas exposure why presence of molecules or small changes in concentration could easily be detected when using graphene as a sensing layer. Graphene is sensitive towards many molecules and in order to detect and possibly identify gas molecules the surface needs to be functionalized. The intention of this project was to use nanoparticles (NPs) to further increase sensitivity and specificity towards selected molecules and also enable biofunctionalization of the NPs, and by that tune the electrical properties of the graphene. This study proposes the use of Fe3O4 and TiO2 NPs to enable sensitive detection of volatile gases and possibly further functionalization of the NPs using biomolecules as a detecting agent in a liquid-phasebiosensor application. The interaction between graphene and NPs have been investigated using several surface charactarization methods and electrical measurements for detection of gaseous molecules and also molecules in a liquid solution. The characterizing methods used are XPS, AFM with surface-potential mapping and Raman spectroscopy with reflectance mapping in order to investigate the NPs interaction with the graphene surface. Sensors where manufactured for gas-phase detection of CO, formaldehyde, benzene and NH3 specifically and display differences in sensitivity and behavior of the Fe3O4 and TiO2 NPs respectively. For liquid measurements the difference in behavior in two buffers was investigated using an in-house flow-cell setup. The surface charecterizing measurements indicated that just a small difference could be found between the two NPs, however a significant change in sensor response could be detected as a function of coverage. The liquid and gas-phase measurements rendered information on differences in sensitivity between the NPs and between analytes where TiO2 showed a higher level of sensitivity towards most of the gases investigated. Both Fe3O4 and TiO2 NP coated graphene showed capability to detect formaldehyde and benzene down to 50 ppb and 5 ppb respectively. The sensitive gas detection could help protecting individuals being exposed to a hazardous level of volatile gases if concentrations increase rapidly or at a long term exposure with lower concentrations, improving saftey and health where these gases are present.
74

The molecular mechanisms of the antimicrobial properties of laser processed nano-particles

Korshed, Peri January 2018 (has links)
Microbial resistance to the current available antibiotics is considered a global health problem, especially for the Multi-Drug Resistant pathogens (MDR) including methicillin resistant Staphylococcus aureus. Recently nanoparticles (NPs) have been involved in variety of antimicrobial applications due to their unique properties of antibacterial effects. However, the molecular mechanisms behind their antibacterial activity are still not fully understood. In this study, we produced silver Ag NPs (average size 27 nm) and silver-Titanium Ag-TiO2 NPs (average size 47 nm) using picosecond laser ablation. Our results showed that both laser NPs had obvious size-dependent antibacterial activity. The laser Ag NPs with a size of 19 nm and Ag-TiO2 NPs with a size 20 nm presented the highest bactericidal effect. The laser generated Ag and Ag-TiO2 NPs with concentrations 20, 30, 40, and 50 Î1⁄4g/ml showed strong antibacterial effect against three bacterial strains: E. coli, P. aeruginosa, and S. aureus, and induced the generation of reactive oxygen species (ROS), lead to cell membrane interruption, lipid peroxidation, DNA damages, glutathione depletion and the eventual cell death. Both types of laser NPs at two concentrations (2.5 and 20 Î1⁄4g/ml) showed low cytotoxicity to the in vitro cultured five types of human cells originated from the lung (A549), kidney (HEK293), Liver (HepG2), skin (HDFc) and blood vessel cells (hCAECs). The antibacterial activity of the laser generated Ag and Ag-TiO2 NPs had lasted for over one year depending on the degree of air exposure and storage conditions. Frequent air exposure increased particle oxidation and reduced the antibacterial durability of the laser generated Ag NPs. The laser generated Ag NPs had lower antibacterial activity when stored in cold compared to that stored at room temperature. The antibacterial activity of laser generated Ag and Ag-TiO2 NPs were also compared with four types of commercial based-silver wound dressings (Acticoat TM, Aquacel® Ag, Contreet ®Foam, and Urgotul® SSD) against E. coli to inform future application in this area. In conclusion, laser generated Ag and Ag-TiO2 NPs have strong bactericidal effect and low toxicity to human cells which could be a type of promising antibacterial agents for future hygiene and medical applications.
75

Analýza spokojenosti zákazníků a návrhy na jejich zlepšení / Customer Satisfaction Analysis and Improvements

Malochová, Šárka January 2017 (has links)
The diploma thesis is focused on customer satisfaction analysis and proposals to increase its level for Provident Financial s.r.o., which has been offering purposeless cash and non-cash loans in the Czech Republic since 1997. The theoretical part describes the issue of marketing research. The practical part is an analysis of the results of a marketing survey conducted on future and existing customers of Provi-dent Financial s.r.o. On the basis of this information, measures are proposed to in-crease customer satisfaction and bring higher sales to the company.
76

Analýza spokojenosti zákazníků cestovní kanceláře a návrhy na její zlepšení / Analysis of Travel Agency Customer Satisfaction and Suggestions for its Improvement

Svoboda, Lukáš January 2020 (has links)
This thesis focuses on increasing the customer satisfaction of travel agency. Customer satisfaction is a key component for maintaining market position, company reputation and its growth. Client satisfaction is especially important in the area of services, including travel agencies. Based on a questionnaire survey among customers, using the NPS method and the KANO model, measures are designed for increasing it. Also the suggestions are obtained to improve company promotion with the use of customer survey.
77

Turtle Cam: Live Multimedia Interaction For Engaging Potential Visitor Population To Canaveral National Seashore

Tortorelli, Brian Alfred 01 January 2012 (has links)
This project expands the outreach of the Canaveral National Seashore to its visitors, potential visitors, and virtual visitors through its goals in conservancy and preservation of its natural resources. This paper is involved with the current iteration of a series of digital media projects, the Sea Turtle Nest Camera, also known as, Turtle Cam. It details how and why this project was designed to be an ongoing initiative to assist in those goals.
78

Using Design Thinking to Explore Millennial Segmentation Gaps and Improve Relevancy within Cuyahoga Valley National Park

Salem, Nidal Eleanor 03 May 2018 (has links)
No description available.
79

Brand personality, congruency, and net promoter score: A university case study

Decker, Cole R. 27 April 2016 (has links)
No description available.
80

A study into the interaction of gold nanoparticles released into drinking water and wastewater system

Raedani, Shumani Alfred January 2016 (has links)
MESHWR / Department of Hydrology and Water Resources / This research involves the investigation of the interaction of different sized Nano Gold particles released into municipal drinking water and municipal waste water. Waste water was collected from Malamulele waste water treatment plant and the municipal water was collected at Mintek in Johannesburg, Randburg, South Africa. The waste water was analysed using ICP-MS to detect the metals and anions in it. The results showed the abundance of Sulphur (464 ppm), Calcium (28 ppm), Chloride (27.8 ppm), Iron (20 ppm), Magnesium (8.2 ppm), silicon (6.192 ppm) in descending order and other trace elements, including gold, that were immeasurable (<0.1). The simulated situation was created by adding 20nm gold and 40nm gold nanoparticles into municipal drinking water and waste water and kept at different environmental conditions (light, light and agitation, dark, dark and agitation) under aerobic and anaerobic conditions over a period of two months. Physico-chemical properties (pH and chemical oxygen demand) of the solutions were checked once in a month. The pH fluctuated between the acceptable ranges (5.5 – 9.5) for the two month period. Both municipal water and waste water, with and without gold nanoparticles, under aerobic condition showed an increase in chemical oxygen demand. The gold content in waste water under anaerobic condition showed an increase while under aerobic condition the decline in gold content was evident. The zeta potential of gold nanoparticles in waste water in light and agitation showed (-30 mV) while waste water on other environmental condition (light, dark and dark with agitation) presenting unstable (-18 mV) charge, but the charge shifted positively on the second month rendering them also unstable. Dynamic light scattering and TEM were used to check any possible aggregation or agglomeration of nanoparticles in the waste water. There were some few discrepancies where TEM and DLS contradict, but overall there was no significant probability of any aggregation of gold nanoparticles. The EDX was used to confirm the presence of Au0 in the waste water (with added gold nanoparticles). The research did show that the gold nanoparticles would exist as Au0 in the waste water and thus the discharge of Au-NPs to the sewer system is not recommended, but rather recycle them.

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