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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.
291

Development of Pd₃Co based catalysts for fuel cell applications and amine based solvents for CO₂ capture : a first principles based modelling of clean energy and clean air technology

Manogaran, Dhivya 24 February 2015 (has links)
With the ever increasing environmental concerns in terms of the need for a vast improvement in clean energy and clean air technologies, this thesis focuses on analyzing the underlying principles that determine the activity of catalysts/sorbents for fuel cell applications and CO₂ capture using first principles based simulations with a view point to help fabricate efficient catalysts. We attempt to clarify the fuzzy concepts of existing surface-nearsurface interactions in Pd based electrocatalysts with particular attention to Pd₃Co alloy catalysts by presenting a thorough inter and intra-layer orbital analysis and bring forth the crucial role played by the surface-subsurface binding driven by the out of plane d-state interactions in determining the surface reactivity. We first decouple the effects induced by the different Pd-Pd and Pd-Co lattice parameters (lattice strain effect) from the hetero atom induced surface-subsurface interaction (we call it "interlayer ligand effect") and clearly demonstrate how enhanced surface-subsurface d [subscript xz+yz] interaction leads to an increased oxygen hydrogenation to H₂O in Pd₃Co based electrocatalysts. We then extend the concept of hetero atom induced surface-subsurface binding to a series of 3d transition metals and provide guidelines for the right choice of metals that may be potential ORR candidates. Finally, we describe the facet dependence and the effect of surface Au alloying on the surface reactivity of Pd₃Co electrocatalysts. In the second section of the thesis, we emphasize on the underlying principles of CO₂ capture by MEA and study the synergetic interplay of various factors that may lead to better CO₂ capture , also enabling efficient solvent regeneration. Though extensive studies are carried out on the most traditionally used alkanol amine MEA for CO₂ capture, there are several less studied aspects like the molecular orbital redistribution on CO₂ binding that decides the fate of the intermediate species and the role of water arrangement in assisting/hindering the progress of the reaction. We study the fundamental CO₂-amine interactions and highlight the crucial importance of alkanol-amine configuration, water arrangement and protonation/de-protonation tendencies at various basic sites in the development of the reaction. We then analyze the synergetic interplay between the inductive effect, the steric hindrance and the resonance in enhancing efficient CO₂ binding and allowing an alternative O-driven mechanism resulting into easy solvent regeneration. We believe that our efforts may help fabricate better catalysts and sorbents and help improve the existing clean energy and clean air technologies. / text
292

Consumer-to-Consumer Online Sharing of Co-Creative Advertising Campaigns

Wright, Gena January 2015 (has links)
This thesis aims to increase understanding of what motivates consumer-to-consumer (C2C) sharing of co-creative advertising campaigns on social media platforms. Consumer use of the Internet has increased immensely, and affects organisations due to the growth of consumer-to-consumer interactions, such as word-of-mouth. Word-of-mouth is a powerful form of advertising because of consumer trust in their social media networks, therefore, it is crucial for organisations to increase C2C sharing as a form of advertising, and in particular, co-creative advertising campaigns. To achieve this aim, this study used a grounded theory approach, to gather a comprehensive amount of data to discover theoretical propositions about the phenomenon. A total of ten unstructured depth interviews were conducted before theoretical saturation was reached. The results of the study found that consumer motivations to share co-creations online were pride, and to connect with others, conceptualised by social media self-presentation, and a consciousness of others. Whilst consumer motivations to participate in co-creative advertising campaigns were escapism and self-interest. The primary implication of these findings is understanding how organisations can influence consumer motivations to share co-creations online, hence, organisations advertising, by increasing personal connections that consumers can use to connect with others in consumer-to-consumer platforms online.
293

Optimal Real-Time Scheduling of Control Tasks with State Feedback Resource Allocation

Gaid, MEMB, Cela, AS, Hamam, Y 27 February 2009 (has links)
Abstract—This paper proposes a new approach for the optimal integrated control and real-time scheduling of control tasks. First, the problem of the optimal integrated control and nonpreemptive off-line scheduling of control tasks in the sense of the H2 performance criterion is addressed. It is shown that this problem may be decomposed into two sub-problems. The first sub-problem aims at finding the optimal non-preemptive off-line schedule, and may be solved using the branch and bound method. The second sub-problem uses the lifting technique to determine the optimal control gains, based on the solution of the first sub-problem. Second, an efficient on-line scheduling algorithm is proposed. This algorithm, called Reactive Pointer Placement (RPP) scheduling algorithm, uses the plant state information to dispatch the computational resources in a way that improves control performance. Control performance improvements as well as stability guarantees are formally proven. Finally, simulations as well as experimental results are presented in order to illustrate the effectiveness of the proposed approach.
294

Effekten på en orts varumärke vid uppköp av en turistanläggning / Effekten på en orts varumärke vid uppköp av en turistanläggning

Grundius, Josefine January 2015 (has links)
Uppsatsen studerar hur en orts varumärkesidentitet förändras då en ny aktör med syfte att locka turister etablerar sig på orten. Den utvalda orten är Trysil där SkiStar köpte skidanläggningen på orten år 2005 och har sedan dess varit ansvarig för vintersäsongen. Destinasjon Trysil, ett destinationssällskap som koordinerar all marknadsföring av Trysil, är ansvarig för marknadsföringen av sommarhalvåret. Varumärkesidentiteten hos Trysil innan uppköpet år 2005 har jämförts med varumärkesidentiteten efter uppköpet och det framgick att det inte har blivit någon nämnvärd förändring. Anledningen till detta har undersökts med hjälp av Smiths (2004) sex kriterier för varumärkesmatchning tillsammans med faktorn kultur, tillsammans omnämnda som förändringsfaktorer. Slutsatsen som dras är att varumärkesidentiteten är densamma då förändringsfaktorerna stämmer väl överrens mellan de båda företagen.
295

The feasibility of using algae as a co-substrate for biogas production : Labpratory experiments of the co-digestion of algae and biosludge / Möjligheten av att använda alger som samsubstrat for biogasproduktion : Laboratoriska experiment av samrötning mellan alger och bioslam

Arkelius, Lisa January 2015 (has links)
Today 88 % of the world energy comes from fossil fuels. Greenhouse gas emissions are increasing and the fossil fuels energy sources will decrease at some point. Other alternatives must be found, to substitute and lower the usage of fossil fuels. Biogas is one of these other options. It is a versatile fossil free fuel that can be used for heat, power and fuel for vehicles. Many different substrates have been used for biogas production over the years, and now algae are examined as a substrate. Algae have advantages over the former substrates used for biogas production. Laboratory experiments were conducted to examine the co-digestion potential of algae and biosludge, which is a rest product from a wastewater treatment plant at a pulp and paper mill. The profitability aspect of using algae and biosludge for biogas production has been examined as well.The result shows that unmixed algae were the highest methane producing substrate, which produced a maximum of 203,5 Nml/g VS. An interesting result was that both algae and biosludge separately produced more methane gas than the mixtures. The profitability aspect of the thesis showed that it is not profitable to use algae primarily for biogas production, based on the conditions of today.
296

Nanoparticle-stabilized supercritical CO₂ foams for potential mobility control applications

Espinosa, David Ryan 20 July 2011 (has links)
The petroleum industry has been utilizing surfactant stabilized foams for mobility control and enhanced oil recovery applications. However, if surface-treated nanoparticles were utilized instead of surfactants, the foams could have a number of important advantages. The solid-stabilized foams are known to have a much better stability than the surfactant-stabilized foams, because the energy required to bring nanoparticles to, and detach from the foam bubble surface is much larger than that of surfactants, and thus the resulting foam will be more stable. Since nanoparticles are the stabilizing component of the foam and are solid, they have potential to stabilize foam at high temperature conditions for extended periods of time. Since they are inherently small, nanoparticles, as well as the foam that they stabilize, can be transported through rocks without causing plugging in pore throats. Stable supercritical carbon dioxide-in-water foams were created using 5 nm silica-core nanoparticles whose surface had short polyethylene-glycol chains covalently bonded to it. The foams were made by injecting CO2 and an dispersion of with surface-treated nanoparticles simultaneously through a glass-bead pack. The fluids flowing through this permeable media created shear rates of about 1350 sec-1. Nanoparticle concentration, nanoparticle coating, water salinity, volume ratios between CO2 and water, temperature and shear rates were systematically varied in order to define the range of conditions for foam generation. Using de-ionized water to dilute the nanoparticle concentration, we were able to generate stable foams were at nanoparticle concentrations as low as 0.05 weight percent. Among the different surface coatings that we tested PEG coatings were the only type that was able to stabilize foam. As the salinity of the aqueous phase increased, the nanoparticle concentration required to maintain foam also increased; for example, 0.5 weight percent nanoparticles were required for 4 weight percent NaCl brine. Foam stability was weakly correlated with volume ratios as foams were made across ratios from two to fourteen, and the normalized viscosity ratio increased with the increase of the phase ratio. Foams were created at temperatures up to 95 degrees Celsius. Foam generation was also determined to require a critical shear rate, which increased with temperature. When foam was stabilized by the nanoparticles, the foam exhibited an increase of between two and twenty times in the resistance of flow compared to the two fluids flowing without nanoparticles. / text
297

Fundamental methodologies and tools for the employment of webometric analyses - a discussion and proposal for improving the foundation of webometrics

Fugl, Liv Danman 06 1900 (has links)
The paper Fundamental methodologies and tools for the employment of webometric analyses defines the most important rules to keep in mind before performing webometric analyses. The paper deals with the two basic elements, that constitutes the foundation for webometric analyses: the documents being analysed, and the tools that are applied for the data collection. The concepts of a citation theory and a link theory are discussed through a study of the current litterature. Different methodologies for uncovering motivations for making references in scientific articles are reviewed and discussed. A methodology for uncovering motivations for making links on webpages is proposed and applied on six researchers' websites at the Royal School of Library and Information Science in Denmark, and on all the institutes at the same institution and at selected institutes at The Technical University of Denmark. The paper further contains a review on the linktopology of the Internet and the current status for the tools available for data collection. Finally, alternative possible tools for applying webometric analyses are proposed. The alternative tools are the Researchindex invented by Lawrence and Giles (Lawrence, Bollacker & Giles, 1999b; Giles, Bollacker & Lawrence, 1998), Kleinberg's HITS algorithm employed in the Clever search engine (The Clever Project, n.d.; Kleinberg, 1998), Proposals for possible extensions to the HTTP protocol to facilitate the collection and navigation of backlink information in the world wide web made by Chakrabarti, Gibson and McCurley (Chakrabarti, Gibson & McCurley, 1999c) and finally Link Agent, a program we have developed for this paper. The program makes it possible to uncover the reciprocal linking webpages, that exist in relation to the outgoing links from a chosen webpage. Keywords: Informetrics, Webometrics, Citation theory, Link theory, Motivations for links, Motivations for references, Search engines, Webometric tools
298

Mapping International Collaboration in Science in Asia through Coauthorship Analysis

Arunachalam, Subbiah, Doss, M. Jinandra 09 1900 (has links)
Using data from SCI 1998, we have analysed international collaboration in science in 11 Asian countries. Papers resulting from collaboration among these countries and with G7, European Union, OECD and selected Latin American and African countries were classified under subject categories to characterize each countryâ s total and collaborated scientific literature output. Japan (16.4% of internationally collaborated papers), India (17.6%) and Taiwan (16.3%) recorded an internationalization index less than 30 whereas China (28.5%), South Korea (24.6%) and Hong Kong (36.2%) recorded an internationalization index greater than 40. India, China and South Korea have collaborated more in physics, whereas the other eight countries have collaborated more in life sciences. In almost all fields and for virtually all Asian countries, USA is the most preferred collaborating partner. All G7 countries collaborate more with China, which is emerging as a leader in regional collaboration, than with India.
299

När vi två blir en : relations- och nätverksbyggande i musikbranschen

Berg, Johanna, Karlsson, Sebastian January 2014 (has links)
The purpose of this paper is to investigate and analyze the importance of networking and relationships in the music industry. We also want to see whether these factors have any impact on the Swedish music exports. These musings have led to the formulation of the following question;   -          How can the musiclabels in the music industry make use of networks and relationships to strengthen the Swedish music exports to the U.S. and make it more efficient?   The essay is written with a qualitative method with an abductive perspective. That’s because our research question has demanded that we get a deeper view of the subject to be able to answer it. The empirical data is collected through telephone or email interviews. Our interviews have been implemented with people who have the knowledge about and are well versed in the industry.   From the theoretical and empirical analysis, some patterns have emerged. The results show that relationships are very important for the various actors in the music industry and most relationships are based on friendships that go back way in time. The networks that exist are informal, but we would like to point out that there are formal networks, in the form of interest- and membership-organizations. Musiksverige that will be presented in the text further on and has a prominent role in this paper is an example of one of those organizations. Trust and commitment is important in the music industry and that is why we belive the actors usually choose to form businessrelationships with old friends or family. Throughout the research we have found that the industry would benefit from a more transparent and structured collaboration, but they are required to communicate with each other and not just to different organizations. A more developed co-opetition would also make the industry more efficient.
300

Non-Invasive Technologies for Condition Monitoring of Synchronous Motors

Sjölander, John January 2014 (has links)
The modern industry today is highly dependent on electric motors of differenttypes and sizes. Synchronous motors are used in applications where a fixedspeed is desired. These machines are often found in high power applicationswhere they are preferred over induction motors due to their higher efficiency.Synchronous motors represent large investments and typically drive processeswhere downtime results in significant capital losses. Thus, detecting faults atan early stage can help avoid catastrophic failures and be useful in thescheduling of maintenance. In order to detect faulty conditions before theyterminate in a failure, machine operators must perform some kind ofmonitoring on the machines. Typically, the more critical the machine is for aprocess, the more effort is put on monitoring it. Before building a monitoringsystem for a machine, one must first decide what parameters that should bemonitored. The obvious desire is to find a parameter that is easy and cheap tomeasure and at the same time can give detailed information about the workingstate of the machine.The aim of this thesis is to evaluate whether the exciter stator current is anadequate parameter to use within a monitoring system for synchronous motors.The evaluation has been made through simulations of two different setups;One using a synchronous motor in the 20 MW range fed by a synchronousmachine type exciter. And the other using the same motor but instead fed byan induction machine type exciter. It has been found that the exciter statorcurrent can be used for detection of faults associated to the rectifier and statorshort circuit of the main machine stator winding. It has not been possible todetect turn-to-turn faults in the main machine rotor.The work has been performed at ABB Corporate Research in Västerås fromJune until December 2013.

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