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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.
441

An evaluation of the use of natural stable isotopes of water to track water movement through oil sands mine closure landforms

2014 March 1900 (has links)
Surface mining of oil sands results in extensive land disturbance, earth movement and water usage. After mining, the disturbed landscapes must be reconstructed and reclaimed as natural landforms. There are numerous challenges associated with understanding the responses of these landforms over time, including a need to track and characterize water movement through closure landforms to understand the hydrological responses of these landforms over time. This study attempted to use natural stable isotopes of water (δD and δ18O) to identify and characterize source waters from various closure landforms at an oil sands mine site. The study area is Syncrude‟s Mildred Lake mine, an open pit oil sands mine located in northern Alberta. A variety of groundwater, surface water and soil samples from a variety of landforms (overburden dumps, composite and mature fine tailings areas, tailings sand structures and freshwater reservoirs) were collected in an attempt to fully represent the isotopic distribution of waters across the mine site. Laboratory analysis of δD and δ18O was done on all samples. The local meteoric water line first established by Hilderman (2011) was redeveloped with additional precipitation data and calculated to be δD=7.0(δ18O) -18.6‰. A natural evaporation line having a slope of 5.3 was calculated for the mine site with samples collected from three surface water ponds on the mine site. Five primary source waters were identified on the mine site: process affected water/tailings, rainfall, snow, interstitial shale water and Mildred Lake water. It was found that these sources of water generally have unique natural stable water isotope signatures. Process affected water at the site generally had an enriched signature compared to other mine waters. The enrichment was attributed to fractionation from the recycle water circuit and natural evaporation. The characterizations of these source waters were then used in several hydrogeological examples to demonstrate that natural stable water isotopes can be applied to water balance estimates and to identify water movement processes related to closure landforms.
442

Relationship between the natural frequencies and fatigue life of NGB–18 graphite / Renier Markgraaff

Markgraaff, Renier Francois January 2010 (has links)
NBG–18 graphite is developed by SGL Carbon for the Pebble Bed Modular Reactor Company (PBMR), and is used as the preferred material for the internal graphite core structures of a high–temperature gas–cooled nuclear reactor (HTR). The NBG–18 graphite is manufactured using pitch coke, and is vibrationally molded. To assess the structural behaviour of graphite many destructive techniques have been performed in the past. Though the destructive techniques are easy and in some cases relative inexpensive to perform, these methods lead to waste material and require cumbersome time consuming sample preparations. To overcome this problem numerous non–destructive testing techniques are available such as sonic resonance, resonant inspection, ultrasonic testing, low and multifrequency Eddy current analysis, acoustic emission and impulse excitation techniques. The Hammer Impulse Excitation technique was used as a method in predicting the fatigue life of NBG–18 graphite by focussing on the application of modal frequency analysis of determined natural frequencies. Moreover, the typical fatigue characteristics of NBG–18 graphite were determined across a comprehensive set of load ranges. In order to be able to correlate modal frequency parameters with fatigue life, suitable uniaxial fatigue test specimen geometry needed to be obtained. The uniaxial fatigue test specimens were manufactured from two NBG–18 graphite sample blocks. The relationship between natural frequencies of uniaxial test specimens, fatigue life, sample positioning and sample orientation was investigated for different principle stress ratios. Load ratios R = –oo and R = +2 tested proved to show the highest r–values for the Pearson correlation coefficients investigated. However, there was no significant trend found between the natural frequency and the fatigue life. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2011.
443

Immunmodulation Dendritischer Zellen durch einen niedrigmolekularen, makrozyklischen Inhibitor (MCS-18) in vivo und in vitro

Horstmann, Brigitte 15 April 2009 (has links) (PDF)
Aus klinischen Studien ist bereits bekannt, dass die aus der Christrose (Helleborus purpurascens) isolierte makrozyklische Substanz MCS-18 in der Lage ist, eine pathologisch aktivierte Immunreaktion wie die rheumatoide Arthritis zu unterdrücken. In der vorliegenden Arbeit stand die Untersuchung der immunmodulatorischen Wirkung von MCS-18 auf dendritische Zellen (DZ) im Vordergrund. Um eine potente Immunantwort zu induzieren, müssen DZ reifen. Hier konnte in vitro gezeigt werden, dass MCS-18 in der Lage ist, die Expression der typischen Reifungsmarker wie CD80, CD86 und vor allem CD83 zu unterdrücken. Darüber hinaus konnte in vitro eine konzentrationsabhängige Reduktion der DZ- T-Zell - Clusterbildung und eine Blockade der DZ-vermittelten T-Zell Stimulation nachgewiesen werden. Im weiteren Verlauf der Arbeit konnte zusätzlich eine dosisabhängige Reduktion der DZ-unabhängigen, anti-CD3/anti-CD28-vermittelten T-Zell Stimulation gezeigt werden. Ferner konnte eine konzentrationsabhängig reduzierte CCR7 -Expression auf der Oberfläche behandelter DZ und daraus resultierend eine eingeschränkte Migrationsfähigkeit der DZ entlang eines CCL19-Gradienten nachgewiesen werden. In vivo besitzt MCS-18 das Potential, die der EAE (ein Mausmodell der humanen Multiplen Sklerose) assoziierten Paralysesymptome sowohl bei prophylaktischer als auch bei einer realen Verhältnisse am nächsten kommenden therapeutischen Gabe zu reduzieren. Selbst bei der Induktion einer zweiten EAE konnte ein lang anhaltender immunsupprimierender Effekt von MCS-18 festgestellt werden. Am bedeutendsten für eine potentielle spätere therapeutische Anwendung am Menschen ist jedoch die Tatsache, dass MCS-18 auch oral verabreicht wirksam bleibt. Histologisch konnte bei mit MCS-18 behandelten Mäusen eine stark reduzierte Infiltration des Gehirns und Rückenmarks mit CD45+ Leukozyten nachgewiesen werden. Zusammengefasst zeigen sowohl die in vitro als auch die in vivo gewonnenen Daten das große therapeutische Potential von MCS-18 für die Therapie von autoimmunen oder anderen immunbedingten Erkrankungen auf.
444

Australian Legal Ramifications of Information System and Data Security Compromise: A review of issues, technology and law.

Quentin Cregan Unknown Date (has links)
Computer intrusions and attacks compromise individuals, companies and communities. Whilst it is clear that computer and information security studies point to a generalised increase in the number and sophistication of computer security attacks over the past decade and that nations now entirely rely upon computer systems, insufficient attention is paid to the protection of those systems. Computer data and network systems affect our everyday lives, from the supply-chain software that ensures that the shelves are stocked at the supermarket, to systems that manage finance and share markets. Compromises of computer security are, therefore, rightly seen both as an attack on those individual entities whose systems and information are compromised, and as a communal attack upon the people and organisations that rely upon or use computer systems, both directly and indirectly. The aim of this thesis is to give an analysis of computer system security, information protections and the legal ramifications of computer security compromise, notably, data security compromise in Australia. Ultimately, the aim is to address three overlapping questions: what are the ways in which systems are breached, what are the legal consequences of a breach and are those consequences adequate? This paper looks at the underlying technology and relationships between actors involved in the majority of security compromises and looks at the common factors in how systems and networks are attacked and actors damaged. The paper then goes on to look at criminal liability for security compromises and shows how a criminal analysis feeds into the proper civil law consideration of the topic. Finally, the paper looks at data security through the lens of privacy. Ultimately, this paper concludes that Australia is inconsistent in its legal responses to information security incidents. Such variations are based on the area of law being discussed and dependent on the breach methodology and outcome. The criminal law provides the most current and potent legal protection any business or individual has had in this field. This is followed by statutory privacy law which provides a narrow degree of coverage and provides only a weak conciliation process for addressing data security issues. Finally, common law and equity provide the most uncertain commercial remedies for those that suffer data security breach. This paper concludes that present protections are inadequate and uncertain, and that change is required.
445

Intrapsychische Entwicklungen in der Familientherapie bei drogenabhängigen Jugendlichen und jungen Erwachsenen eine kontrollierte Verlaufsuntersuchung an den Indexpatienten, ihren Eltern und Geschwistern

Lehmann-Habeck, Martin January 2005 (has links)
Zugl.: Hamburg, Univ., Diss., 2005
446

Molecular and cytogenic studies of oncogene alterations in human breast and cervical carcinomas /

Zhang, Anju, January 2002 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.
447

Candidate gene analyses and genome-wide screens in multiple sclerosis /

Giedraitis, Vilmantas, January 2002 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.
448

Immunomodulation and its effector mechanisms in atherosclerosis /

Hjerpe, Charlotta, January 2007 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 5 uppsatser.
449

Sexualität und Bindung Qualität und Motivation sexueller Paarbeziehungen im Jugend- und jungen Erwachsenenalter

Wendt, Eva-Verena January 2007 (has links)
Zugl.: München, Univ., Diss., 2007 u.d.T.: Wendt, Eva-Verena: Sexualität und Bindung bei jungen Paaren
450

Exklusion und Selbstbehauptung wie junge Menschen Armut erleben

Thomas, Stefan January 2009 (has links)
Zugl.: Berlin, Freie Univ., Diss., 2009

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