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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.
1

Alkene hydroformylation catalysed by dinuclear rhodium complexes

Epton, Jeremy W. January 1990 (has links)
No description available.
2

Complete nonnegatively curved spheres and planes

Hu, Jing 21 September 2015 (has links)
We study the space of complete Riemannian metrics of nonnegative curvature on the sphere equipped with C^{k+\alpha} topology. We show the space is homogenous for k>=2. If k is infinite, we show that the space is homeomorphic to the separable Hilbert space. We also prove for finite k, the space minius any compact subset is weakly contractible.
3

Invariant differential equations on homogeneous manifolds

Helgason, S. January 1977 (has links)
First published in the Bulletin of the American Mathematical Society in Vol.83, 1977, published by the American Mathematical Society
4

Comparing the Performance of Heterogeneous and Homogeneous Swarms

Hales, Jason Alexander 15 December 2007 (has links)
This thesis compares the performance of heterogeneous and homogenous swarms. Swarms are defined as particles or agents which react to their environment and fellow particles or agents according to social rules. The weights of three attributes of an individual agent were varied for these experiments: Collision Avoidance with individual agents in the swarm, Center of Mass of the swarm and the parameter that controls Velocity Matching in the swarm. In homogenous swarms, all individuals had the same attribute weights while in heterogeneous swarms weights for one attribute were taken from a normal distribution for the population. These swarms were then given goals on a map to pursue. The maps were two-dimensional grid-surfaces with terrains of open, mountain and swamps. Performance was defined as the number of steps it took for 90% of the swarm to reach its final goal. The results show that heterogeneous swarms outperformed homogenous swarms if the weights for the Center of Mass Weight attribute were heterogeneous in the population. The Collision Avoidance and Matched Velocity attributes showed little performance difference for heterogeneous and homogenous swarms for the parameter weights tested. However, swarms heterogeneous in the Matched Velocity parameter showed substantial performance improvements for the most difficult map.
5

Transition metal catalyzed regioselective carbon-carbon bond formation mediated by transfer hydrogenation

Sam, Brannon 03 September 2015 (has links)
One of the more formidable challenges in the synthesis of complex organic molecules remains the efficient formation of carbon-carbon bonds. The development of a broad class of reactions to achieve this goal involves the addition of carbon based nucleophiles to carbonyl and imine compounds. Until recently, classical approaches to carbon-carbon bond formation generally required the use of stoichiometric pre-formed organometallic reagents to serve as nucleophiles, which translate into stoichiometric organometallic byproducts. In an effort to minimize nucleophile pre-activation and byproduct formation, our lab has developed efficient methods for carbonyl and imine additions via in situ formation of alkyl metal nucleophiles from π-unsaturates. The research reported herein describes our advances in an assortment of transition metal-catalyzed carbon-carbon bond forming reactions mediated by transfer hydrogenation, including regioselective hydrohydroxymethylation, hydrohydroxyfluoroalkylation, and hydroaminomethylation. Additionally, the investigation of regioselective carbonyl vinylation is reported. / text
6

Is it good being the same? : a study on Diversity

Nilsson, Daniel, Pizevski, Christian January 2014 (has links)
In today’s society, companies strive to become diverse. Some organizations want to make us believe, that they like new thinking and want to integrate diversity into their organization. By using diversity management as a tool of analysis it is possible for organizations to work with diversity. Diversity is viewed as something positive by the public and therefore, is it possible to use it as an advantage. The purpose of this dissertation is to understand how organizations think about diversity and to give an idea of how organizations understand the term diversity. The aim is to explore how organizations understand diversity and what it will provide for the organizations. The outcome of this research will give a better overview of diversity in organizations. A qualitative research was made and respondents from three different companies were used, to understand how companies define diversity. Furthermore, this dissertation provides an idea of what type of characteristics that organizations think are important for diversity and what effects that may have.
7

Is it good being the same? : a study on diversity

Nilsson, Daniel, Pizevski, Christian January 2014 (has links)
In today’s society, companies strive to become diverse. Some organizations want to make us believe, that they like new thinking and want to integrate diversity into their organization. By using diversity management as a tool of analysis it is possible for organizations to work with diversity. Diversity is viewed as something positive by the public and therefore, is it possible to use it as an advantage. The purpose of this dissertation is to understand how organizations think about diversity and to give an idea of how organizations understand the term diversity. The aim is to explore how organizations understand diversity and what it will provide for the organizations. The outcome of this research will give a better overview of diversity in organizations. A qualitative research was made and respondents from three different companies were used, to understand how companies define diversity. Furthermore, this dissertation provides an idea of what type of characteristics that organizations think are important for diversity and what effects that may have.
8

Cycloalkane Metathesis using a Bi-metallic System: Understanding the Effect of Second metal in Metathesis Reaction

Alshanqiti, Ahmed M. 09 1900 (has links)
Over the past decades, since the discovery of a single–site silica-supported catalyst for the alkane metathesis reaction by our group, we have been extensively working on the development of supported catalytic systems for the improved alkane metathesis reaction. During these developments, we understand the reaction mechanism and reached a new perspective for the synthesis of various supported bimetallic systems via the surface organometallic chemistry (SOMC) approach. Recently, with this bi-metallic system, we got a very high TON (10000) in propane metathesis reaction. As these catalysts are very efficient for linear alkanes we thought to apply it for cyclo-alkanes specifically, for cyclo-octane metathesis expecting better activity. Besides, the value of the ring alkanes are higher than the linear alkanes. The current work demonstrates a combination of [(ΞSi−O−)W(Me)5] and [(ΞSi− O−)Ti(Np)3 pre-catalyst with several supports (SiO2-700, SBA-15 and MCM-41) for metathesis of cyclooctane. The catalysts have been synthesized and fully characterized by elemental analysis (EA), FT-IR and NMR spectroscopies. After fully characterization the bi-metallic catalyst was tested for metathesis of cyclooctane with highest ever TON 2500 as compared to that of mono-metallic catalyst where we got 430 TON. Which again corroborates our prediction that bimetallic catalysts are better catalysts than monometallic catalysts.
9

Ruthenium- and Manganese-Catalyzed C−O and C−C Formation via C−H Activation

Liu, Weiping 06 June 2016 (has links)
No description available.
10

Cycloalkane Metathesis using a Bi-metallic System: Understanding the Effect of Second metal in Metathesis Reaction

Alshanqiti, Ahmed M. 12 1900 (has links)
Over the past decades, since the discovery of a single–site silica-supported catalyst for the alkane metathesis reaction by our group, we have been extensively working on the development of supported catalytic systems for the improved alkane metathesis reaction. During these developments, we understand the reaction mechanism and reached a new perspective for the synthesis of various supported bimetallic systems via the surface organometallic chemistry (SOMC) approach. Recently, with this bi-metallic system, we got a very high TON (10000) in propane metathesis reaction. As these catalysts are very efficient for linear alkanes we thought to apply it for cyclo-alkanes specifically, for cyclo-octane metathesis expecting better activity. Besides, the value of the ring alkanes are higher than the linear alkanes. The current work demonstrates a combination of [(ΞSi−O−)W(Me)5] and [(ΞSi− O−)Ti(Np)3 pre-catalyst with several supports (SiO2-700, SBA-15 and MCM-41) for metathesis of cyclooctane. The catalysts have been synthesized and fully characterized by elemental analysis (EA), FT-IR and NMR spectroscopies. After fully characterization the bi-metallic catalyst was tested for metathesis of cyclooctane with highest ever TON 2500 as compared to that of mono-metallic catalyst where we got 430 TON. Which again corroborates our prediction that bimetallic catalysts are better catalysts than monometallic catalysts.

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