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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

Pyrolysis Kinetics and Chemical Structure Considerations of a Green River Oil Shale and Its Derivatives

Hillier, James L. 16 March 2011 (has links) (PDF)
This work had the objective of determining both the kinetic parameters for the pyrolysis of oil shale and kerogen as well as using analytical techniques coupled with pyrolysis to shed light on the structure of a specific Green River oil shale. Because of the problems with linearized methods and disagreement among literature values and methods, a new method was developed tofit kinetic parameters to non linearized data. The method was demonstrated to determine the "correct" answer for mathematically generated data within a few percent error and was shown to have a lower sum squared error than the linearized methods. The curve-fitting methodology was then applied to pyrolysis kinetic data for kerogen and oil shale. Crushed samples were pyrolyzed at heating rates from 1 to 10 K/min and at pressures of 1 and 40 bar. The transient pyrolysis data were fit with a first-order model and a progressive Distributed Activation Energy Model (DAEM). An F-test was used to determine confidence regions and compare the kinetic parameters among the samples. The activation energies determined ranged from 173 to 226 kJ/mol, with most values around 200-220 kJ/mol. The kinetic coefficients determined for oil shale and the demineralized samples were statistically the same. Only small differences in kinetic coefficients were seen in the size-graded samples. The first-order and DAEM were shown to be statistically different, but a visual inspection of a graph of the model predictions and the data revealed that both models performed well. The largest effect on the kinetic parameters was between samples collected from different geographic allocations. The pyrolysis products (and the parent kerogen sample) were analyzed by several chemical techniques to determine chemical structure information about the parent sample. TheGC/MS data for the tars collected showed a distribution of alkenes/alkanes with 11 to 12 carbonsin length being the most frequent. XPS analysis demonstrated that any chemical model must have pyridinic and pyrrolic nitrogens as well as carbonyls and carboxyl groups. Therefore a chemical structure model of kerogen should have heteroatoms of nitrogen in the aromatic region(i.e., the portions of the kerogen that are stable at moderate temperatures).
2

Centre for Media + Image

Bevan, Blanche 12 October 2006 (has links)
The following dissertation is located in South Africa, Pretoria. The aim is to define the Threshold of entry from the South of Pretoria, passing the University of South Africa and via Elandspoort Road and Mears Street. An Urban Design and Centre for Media + Image form the final resolution for the proposal. Education and Display are explored in creating a facility for the University of South Africa and a public and visual venue for Pretoria. Connection and Communication are the theoretical concepts carried through into the design. This is done in order to fully integrate design within a context both locally and internationally. Visual interaction with the building in the following design is a major factor. This is due to the dynamics surrounding the site and already existing movement channels and patterns creating an Urban Environment. The work of Bill Hillier has been consulted in relation to Architecture and Movement. The design approach is one of aknowleding our place in time. This is reflected in the programme for the facility and in the environment and technologies incorporated. Tilt-Up Construction, Post-Tensioned Slabs and Steel Construction are the main building methods. Steel, Glass and Concrete make up the material palette in conjunction with technological advances such as nanotechnology and smart surfaces. Steel and Glass Louvre Systems with Nanotechnology enable Large Screen Display on external Surfaces of the Facility. Copyright 2006, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Bevan, B 2006, Centre for Media + Image, MArch(Prof) dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-10122006-121826/ > / Dissertation (MArch (Prof))--University of Pretoria, 2007. / Architecture / unrestricted
3

Rumslig Navigering- en komparativ studie av människans förmåga att orientera sig i urbana miljöer

Antoan, Salam, Zelenka, Tomas January 2010 (has links)
I denna uppsats presenteras en jämförande studie av tre gators rumsliga begriplighet (intelligibility). Studieobjekten är Trollebergsvägen, Karl XI-gatan och Öresundsvägen i Lund. Öresundsvägen är föremål för exploatering under kommande år. Här kommer det att skapas en mängd olika byggnader där olika grupper i samhället kan bosätta sig och leva. En rad nya företag kommer att etablera sig. I uppsatsen används det kvantitativa verktyget Space syntax tillsammans med kvalitativa fallstudier för att mäta den rumsliga orienteringsförmågan på dessa gator. Bill Hillier har funnit ett samband mellan integration och connectivity som han menar påverkar begripligheten av en viss rumslig struktur för människan. Han har kallat korrelationen för intelligibility- rumslig begriplighet. I uppsatsen jämförs Space syntax analyser med fallstudier för att utröna om Hilliers teori stämmer och för att därmed försöka bidra till utvecklingen av verktyg för att mäta rumslig navigering i urbana miljöer. Resultat är att använda båda analysmetoderna tillsammans vid mätningen av intelligibility. / In this paper we introduce a comparative study on three streets’ intelligibility. The study objects are Trollebergsvägen, Karl XI gata and Öresundsvägen in Lund, Sweden. Öresundsvägen is under negotiation for development in coming years. Here, there will be a variety of building structures allowing mixed social groups to live side by side and also businesses established close to the inhabitants. We have used the quantitative method Space syntax and the qualitative data of case studies to measure the intelligibility of these streets. Since Bill Hillier has found a correlation between integration and connectivity to affect the intelligibility that local and global streets produce, we will compare Space syntax analysis with the qualitative case studies in order to investigate and evaluate Hillier’s claims. In doing so we do two Space syntax analysis of integration and connectivity of the city with tables showing values for the streets. Results of this study shows that these two types of analysis would give a better understanding of intelligibility when are used.

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