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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.
241

Micro-modeling and study of the impact of microstructure on the performance of solid oxide fuel cell electrodes

Abbaspour Gharamaleki, Ali 11 1900 (has links)
As the demand for green energy and fuel cells grows, more attention is drawn towards Solid Oxide Fuel Cells (SOFCs). Random and complex structure of composite electrodes and underlying electrochemical process has not been completely unveiled yet and further study is required to acquire more understanding. Modeling in this regard plays an important role as it pinpoints key parameters in optimum design of the cell without resorting to costly and uncertain experiments which might even lead to misinterpretations due to random nature of experimental data. The aim of this work is to develop a new rigorous model to study the structure performance relationship of (SOFC) composite electrodes. The work has been conducted in two phases, a two-dimensional continuous approach and three-dimensional discrete model. A new two-dimensional, geometrical model which captures the inhomogeneous nature of the location of electrochemical reactions based on random packing of electronic and ionic conducting particles has been developed. The results show that the concentration of oxygen inside the cathode in the two-dimensional model is not only a function of the electrode depth but also changes along the width of the electrode. Furthermore the effect of composition of the electrode on the length of three phase boundary (TPB) and total polarization resistance has been demonstrated. A parametric study of the effect of the conductivity of ionic conductor and diffusion coefficient on the performance of the electrode has been given. To make a more realistic analysis, a three-dimensional reconstruction of (SOFC) composite electrodes was developed to evaluate the performance and further investigate the effect of microstructure on the performance of electrodes. To enhance connectivity between particles and increase the length of TPB, sintering process is mimicked by enlarging particles to certain degree. Geometrical characteristics such as length of TBP and active contact area as well as porosity can easily be calculated using the current model. Electrochemical process is simulated using resistor-network model and complete Butler-Volmer equation is used to deal with charge-transfer process on TBP. The model shows that TPBs are not uniformly distributed across the electrode and location of TPBs as well as amount of electrochemical reaction is not homogeneous. Effects of particle size, electrode thickness, particle size ratio, electron and ion conductor conductivities and rate of electrochemical reaction on overall electrochemical performance of electrode are investigated. / Chemical Engineering
242

Barriers and outcomes of the collaboration between industry and academia in a new approach: the Living Labs

Englund, Mikael, Felice, Quentin January 2010 (has links)
The importance for companies in knowledge or technology intensive industries to take part in research partnerships has been thoroughly researched, and the gain of collaboration with external parties has been proven. One of these most influential collaboration types is the one between academia and industry, where the US Bayh-Dole Act provided a break-through policy change for the transfer, conversion and commercialization of knowledge and innovations. To counter this, the European Union has implemented a policy around a facilitating, user-centered milieu for innovation called Living Labs. In this article, the purpose is to identify potential collaboration barriers in the university-industry collaboration when implemented in this milieu. This is done by using a multiple case study where the respondents are seven individuals, from three Living Lab entities and two companies. The findings show that the inclusion of users give the setting its advantage, but also gives additional management needs, something that applies to all participants in the setting – the company representatives must have a diverse set of abilities, the researchers should be standalone and independent from the Living Labs management, the management must establish a shared physical context for all parties to interact within and there must be a very clear agreement between all parties what there are expecting from the collaboration regarding outcomes, process and structure.
243

ICA:s Hållbarhetsredovisning med tillämpning av GRI : Vad bestämmer leverantören?

Huléen, Jonas, Hising, Per January 2009 (has links)
Syftet är att utifrån GRI:s riktlinjer undersöka ICA:s hållbarhetsredovisning samt jämföra den med den generella uppfattningen som intressentgruppen leverantörer har om hållbarhetsredovisningar. ICA tar GRI:s riktlinjer på stort allvar vid tillämpning av dessa vid upprättandet av sin hållbarhetsredovisning. Leverantörernas intresse påverkar ett flertal resultatindikatorer som ICA inte har definierat som resultatindikatorer valda utifrån leverantörernas intresse.
244

How can companies benefit from business ethics? : A study of business ethics in the baby nutrition market

Scharmer, Carl, Andersson, Emma January 2007 (has links)
Abstract Problem: Increased information flow and augmented knowledge have together with increased competitiveness created restrictions for companies aiming not to consider the environmental and social aspects in their goals. Stakeholders have started to consider these aspects to larger extent recently. However, many companies do not see the opportunities with using an ethical approach, and whether they will benefit from it. Purpose: The purpose of the thesis is to examine how companies can benefit from practicing business ethics within the organizations, by comparing theoretical studies and empirical findings. Method: Due to the purpose, a qualitative method approach was chosen. Data were collected through semi-structured telephone interviews with all respondents. The selection of interviews consist of the three largest actors on the Swedish baby nutrition market; HIPP, Nestlé, and Semper. Conclusion: Companies benefit from applying an ethical approach, in terms of environmental and social goals into the organization. Ethics is still a complex concept, with several definitions. Companies may use the TBL model for their implementation of the two additional aspects, to make it more concrete. The ethical approach includes work beyond what is regulated and legislated. The motivational factors for companies applying ethics vary, nevertheless the stakeholders’ interest for the company increase with environmental and social aspects included in the goals. To evaluate the ethical standpoint it is important for companies to verify whether their approach is correctly made and if it accurate received. Evaluating an ethical approach is however, difficult to make due to the complexity of the concept and its intangibleness.
245

Scientific research and economic activity : the perceptions of academic and industrial scientists of the production and capitalization of knowledge

Dzisah, James Sefe 07 December 2006
Knowledge production has changed considerably in the past few decades. This transformation has notably affected universities both as unique institutions and citadels of knowledge. These changes are being brought by a number of factors, such as the globalization of the economy, the rise of technologies based on generic forms of knowledge, and the ability of universities to hold and exploit patents. In both scale and intensity, these alterations have led policy makers to reflect more on how scientific and technological innovation can and should be enhanced by policy decisions that would improve university-industry and government cooperation. This new fusion of three complementary societal sectors has been described by sociologists as the triple helix. As an analytical and normative concept, the triple helix is derived from the changing role of government in different societies in relation to academia and industry. Its basis is the recognition that the interaction among university-industry-government as relatively independent, yet inter-dependent institutional spheres is critical to improving the conditions for innovation in a knowledge-based society. The study reveals that commercial research funding significantly affects the perceptions of university-industry collaboration and academic knowledge capitalization. The analysis showed that academic scientists who received commercial research funding have relatively positive views about university-industry relations than those who do not receive such funds. However, one cannot conclude that commercial activities of academic scientists are harming the core functions of the university or that intellectual autonomy is being surrendered to industrial partners. Based on the findings of the study, and the contours of the triple helix model, it is argued that the growth of university-industry-government collaboration is not necessarily pre-determined in favour of either private corporations or the state, nor is it necessarily at the expense of universities. It is further contended that the growing notion that academic capitalism is harming the core functions of the university is perhaps a bit simplistic in that the issue is more complex and multifaceted than usually acknowledged. <p>In light of the above, the study asserts that the future viability of policies encouraging universities to be entrepreneurial may, if approached strategically, be catalysts for the science-based knowledge economy. For that to be realistic there is the need to understand the university as a differentiated social system rather than a unified whole. This will avoid the situation whereby all university activities are subordinated under a homogenous policy of one size fits all. In the context of triple helix relations, conceptualizing the university as a differentiated social system means a deep-seated and continually growing purposeful specialization such as the adoption of an economic development function in addition to teaching, research and community engagement.
246

Desarrollo de metodología analítica para la determinación de residuos de contaminantes orgánicos en aguas y vegetales mediante LC-MS/MS con analizador de triple cuadrupolo

Marín Ramos, Jose Manuel 06 July 2010 (has links)
En esta Tesis se investiga el potencial analítico y la aplicabilidad del acoplamiento instrumental cromatografía líquida-espectrometría de masas en tándem con analizador de triple cuadrupolo (LC-MS/MS), para la determinación de contaminantes orgánicos en muestras de aguas y vegetales. Para ello, se han seleccionando compuestos cuya determinación analítica presenta dificultades, bien por su elevada polaridad o por problemas en su ionización, así como contaminantes prioritarios desde el punto de vista medioambiental. Toda la metodología analítica incluida en la Tesis se ha desarrollado teniendo en cuenta la legislación europea vigente, tanto en lo relativo a la sensibilidad requerida en los métodos analíticos según los niveles máximos de residuos permitidos, como a los parámetros de calidad relacionados con la instrumentación analítica y los métodos empleados. En consecuencia, los resultados que se presentan pueden ser considerados satisfactorios y fiables, desde el punto de vista cuantitativo y cualitativo. La excelente sensibilidad y selectividad alcanzadas, así¬ como la rapidez y robustez de los métodos desarrollados hace factible su aplicación en análisis rutinarios de muestras.La Tesis se estructura en dos grandes bloques. En el primero de ellos se incluye el desarrollo, validación y aplicación de métodos multirresiduales por LC(UHPLC)-MS/MS, para la determinación de plaguicidas y productos de transformación (TPs) en aguas, tanto medioambientales (superficiales y subterráneas) como procedentes de los lixiviados de una planta de residuos sólidos urbanos. En el segundo bloque se describen métodos individuales para compuestos de especial interés analí¬tico y/o medioambiental, cuya determinación a nivel de residuos, tanto en aguas como en vegetales, requiere metodologías avanzadas sensibles y selectivas.
247

Teleseismic Imaging of the Crust and Upper Mantle in the Western United States

Liu, Kaijian 06 September 2012 (has links)
High-resolution seismic images of lithospheric structures allow us to infer the tectonics that modified the lithosphere. We apply such methods to understand Cenozoic modification of the lithosphere by tectonic and magmatic processes in the tectonically active western United States. Using USArray Transportable and Flexible Array data, we present high-resolution images for three regions in this thesis. (1) In the Mendocino triple junction, we use a joint inversion of Rayleigh-wave dispersion data and receiver functions to obtain a new crust and upper Vs model to ~150km depth. The model shows four distinct, young lithosphere-asthenosphere boundary systems. A low-Vs anomaly beneath the Great Valley-Sierra Nevada reconciles existing slab window models with the mantle-wedge geochemical signatures in Coast Range volcanics, and explains the ~3 Myr delay of the onset of volcanism after slab removal. Uppermost mantle low velocities provide evidence for forearc mantle serpentinization extending along the Cascadia margin. (2) In the Colorado Plateau, a Rayleigh wave tomography model sheds light on the volcanism along the margins and plateau uplift. Strong upper mantle heterogeneity across the plateau edge results from the combined effect of a ~200-400 K temperature difference and ~1% partial melt. A ring of low velocities under the plateau periphery suggests that the rehydrated Proterozoic lithosphere is progressively removed by convective processes. Particularly, a high-Vs anomaly imaged beneath the western plateau adds evidence for a downwelling/delamination hypothesis [Levander et al., 2011]. Thermo-chemical edge-driven convection causing localized lithospheric downwelling provides uplift along the margins and magmatic encroachment into the plateau center. (3) In the final study, we developed a 3-D teleseismic scattering wave imaging technique based on the Kirchhoff approximation and 3-D inverse Generalized Radon Transform. Synthetic tests demonstrate higher resolution imaging for continuous, irregular interfaces or localized scatterers, in comparison to conventional methods. Applied to the High Lava Plains dataset, the transmission coefficient structure shows a deepening Moho near 117.6°W and three negative events that correlate well with the Rayleigh wave low-Vs zones. Images made with the Mendocino data clearly show rapidly decreasing lithosphere-asthenosphere boundary depths from the subduction to transform regime.
248

The Self-Calibration Method for Multiple Systems at the CHARA Array

O'Brien, David P 07 May 2011 (has links)
The self-calibration method, a new interferometric technique using measurements in the K′-band (2.1 μm) at the CHARA Array, has been used to derive orbits for several spectroscopic binaries. This method uses the wide component of a hierarchical triple system to calibrate visibility measurements of the triple’s close binary system through quasi-simultaneous observations of the separated fringe packets of both. Prior to the onset of this project, the reduction of separated fringe packet data had never included the goal of deriving visibilities for both fringe packets, so new data reduction software has been written. Visibilities obtained with separated fringe packet data for the target close binary are run through both Monte Carlo simulations and grid search programs in order to determine the best-fit orbital elements of the close binary. Several targets, with spectral types ranging from O to G and luminosity classesfrom III to V, have been observed in this fashion, and orbits have been derived for the close binaries of eight targets (V819 Her B, Kappa Peg B, Eta Vir A, Eta Ori Aab, 55 UMa A, 13 Ceti A, CHARA 96 Ab, HD 129132 Aa). The derivation of an orbit has allowed for the calculation of the masses of the components in these systems. The magnitude differences between the components can also be derived, provided that the components of the close binary have a magnitude difference of Delta K < 2.5 (CHARA’s limit). Derivation of the orbit also allows for the calculation of the mutual inclination (Phi), which is the angle between the planes of the wide and close orbits. According to data from the Multiple Star Catalog, there are 34 triple systems other than the 8 studied here for which the wide and close systems both have visual orbits. Early formation scenarios for multiple systems predict coplanarity (Phi < 15 degrees), but only 6 of these 42 systems are possibly coplanar. This tendency against coplanarity may suggest that the capture method of multiple system formation is more important than previously believed.
249

The Fair Trade Coffee Business Model’s Affect on the Small Scale Producers through the Lens of the Triple Bottom Line

Krupka, Joseph 31 July 2012 (has links)
The aim of this study is to understand the Fair Trade Coffee Business Model by determining how the Fair Trade Coffee Business Model affects the livelihoods of the small scale producers in developing countries. The Fair Trade Coffee Business Model is driven by the mission to improve the well-being of the small scale producers located in developing countries through the lens of the Triple Bottom Line (economic, social and environment). What is the significance of fair trade coffee to the economies of developing countries that produce coffee? The economies are considerably impacted by coffee production as coffee ranks as the second foremost exported commodity from developing countries (European Coffee Federation, 2006). Ensuring the small scale producers receive a fair price for the coffee they grow is only one of the initiatives of the model. Other key initiatives include pre-harvest financing, increased healthcare services, working together for a higher quality coffee, fairer business conduct, improvements in education, and technical assistance. The findings of this study provide some insights into the Fair Trade Coffee Business Model’s effect on the livelihoods of the small scale producers in developing countries through the lens of the Triple Bottom Line. The Fair Trade Coffee Business Model has increased the quality of the coffee bean produced by the small scale producers along with developing long term business relationships throughout the Fair Trade Coffee Business Model supply chain. In sum, the small scale producers reported that the Fair Trade Coffee Business Model has a positive effect on their livelihood and well-being. More specifically, they also indicated that the motivations for them to participate in the Fair Trade Coffee Business Model are receiving a better price for coffee, democratic decision making and farm training. An additional finding affirms that the Fair Trade Coffee Business Model is a sound contributor to the socio-economic stability of the small scale producers, offering a sustainable income-generating alternative market strategy.
250

Macro theory induced micro practice : A case study of a Triple Helix inspired innovation project

Kjellin, Per, Missaoui, Jonas January 2012 (has links)
Europe is arguably in need of a more offensive approach towards theencouragement of entrepreneurship and research based product development.Several European initiatives have been initiated towards this aim, one ofwhich is the Knowledge and Innovation Communities (KICs); an initiativeultimately taken by the European Commission. The main purpose of the KICsis to foster innovation and commercialization in Europe by combining forcesof industry and university, much in line with the theory of the TripleHelix. This master’s thesis is a follow up report of a previously conductedRemotely Operated Vehicle (ROV) market analysis, which was a deliverable inthe OTS project; a KIC InnoEnergy initiated project, aiming towards productdevelopment within the ocean energy sector. The purpose of this thesis hasbeen to, on the one hand evaluate how such a multidisciplinary projectworks in practice, the consequences of its design and the coping of theseconsequences, and on the other hand to identify and map prerequisites for asituation regarding if, and how, the project should invite anotherparticipant from industry into a collaboration. Based on a qualitativeanalysis of seven interviews with representatives from both academia andindustry, the conclusions indicated that the structure and future of theOTS/ROV project is perceived as unclear, best remedied by strongermanagement, additional funding, and invitation of a new collaborator. Thedemands for such collaboration mainly include an explicit project plan fromthe external ROV supplier’s point of view, and the sharing of knowledge andequipment of the supplier from the internal members’ point of view.

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