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Thesis (MA)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: This study explores patterns of separation and/or connection in the narratives of the respondent, a female farm worker living and working in the Western Cape, South Africa. The major objective of this qualitative case study is to examine the possible construction, co-existence and interaction of separation-connection themes in the reality of the respondent. Founded within the social constructivist tradition, an approach that assumes reality to be constructed through language and within relationships, a window on the respondent's narrative construction of her reality, relationships and separation-connection processes was obtained. To compliment the explorative nature and social constructionist approach of the study, Grounded Theory and Narrative Analysis were administrated. Through the analysis the two central themes, separation and connection, manifested on two different levels - firstly on a content level (what the participant has to say regarding the themes) and secondly on a process level (what is happening between participant and researcher). Findings provided a preliminary understanding of the techniques the respondent implores to construe a sense of separation and connection. Results confirmed the co-existence of separation-connection themes and indicated a possible interaction between the two constructs. Findings also provided a glimpse on the experiences and impact of the separation-connection process in the idiom of the respondent. / AFRIKAANSE OPSOMMING: Die studie belig patrone van binding en/of skeiding in die narratiewe van die respondent, In vroulike plaaswerker in die Wes-Kaap, Suid-Afrika. Dié kwalitatiewe gevallestudie is gerig op In ondersoek van die potensiële konstruksie, naasbestaan en interaksie van binding- en/of skeidingstemas soos wat die respondent dit beleef en verwoord. Deur die fundering van die navorsing in die sosiaal-konstruktivistiese tradisie, In benadering wat glo dat die realiteit in verhoudings via taal gekonstrueer word, is toegang tot die respondent se narratiewe konstruksie van haar realiteit, verhoudings en binding- en/of skeidingstemas verkry. In ooreenstemming met sosiaal-konstruktivistiese aannames, het die data-analise Narratiewe Analise en Grounded Theory metodiek behels. Met behulp van die ontleding het die twee sentrale konsepte, binding en skeiding, op twee vlakke gemanifesteer - eerstens op In inhoudsvlak (dit wat die respondent daaroor vertel) en tweedens op In prosesvlak (dit wat tussen die respondent en die onderhoudvoerder gebeur). Die resultate bied In voorlopige verstaan van die wyses waarop die respondent binding en/of skeiding konstrueer. Bevindings bevestig die naasbestaan van binding- en skeidingstemas en dui op In moontlike interaksie tussen dié twee konstrukte. Die studie verskaf ook In blik op die respondent se ervaring van die konstrukte in haar eie idioom.

There are currently three known crystal packing motifs of boronsubphthalocyanine derivatives. Each motif is associated with a particular class of BsubPc derivatives, and none are ideal for organic electronic applications according to the criteria we defined for evaluation: having a continuous pathway for charge-carrier conduction in the solid-state, resistance to hydrolysis, good electrochemical and optical properties, and possession of a robust crystal form. In this thesis, we present five methods for altering the crystal packing structure of phenoxy-BsubPc derivatives in order to meet the above four criteria. We find that neither addition of steric bulk to the axial derivative nor changing the symmetry of the compounds is sufficient for creating a new crystal packing motif. We do find that reducing the symmetry of the axial group does increase the solubility greatly, however. We identify a new motif for BsubPc crystals that occurs when the intermolecular interactions between the axial phenoxy segment and the BsubPc ligand are increased. We present two methods for achieving this new motif, one is through addition of a π-Br interaction and the other is through creation of a strong π-acid/ π-base stacking by making the axial phenoxy more π-electron rich. Unfortunately, the p-bromophenoxy-BsubPc forms this new motif as a kinetic product, isolation of which is unreliable. Attaching a naphthol fragment axially to the BsubPc creates a stable version of this new motif. We also synthesized a new class of BsubPc pseudohalides based on sulfonate derivatives. Of the derivatives in this new class, we found that mesylate-BsubPc forms into a crystal packing structure that possesses a one-dimensional pathway for charge carrier mobility, but is still resistant to hydrolysis under the conditions tested. Overall, we show four compounds that meet the criteria for further study as organic electronic materials: p-methoxyphenoxy-BsubPc, α-naphthoxy-BsubPc, β-naphthoxy-BsubPc, and mesylate-BsubPc.

There are currently three known crystal packing motifs of boronsubphthalocyanine derivatives. Each motif is associated with a particular class of BsubPc derivatives, and none are ideal for organic electronic applications according to the criteria we defined for evaluation: having a continuous pathway for charge-carrier conduction in the solid-state, resistance to hydrolysis, good electrochemical and optical properties, and possession of a robust crystal form. In this thesis, we present five methods for altering the crystal packing structure of phenoxy-BsubPc derivatives in order to meet the above four criteria. We find that neither addition of steric bulk to the axial derivative nor changing the symmetry of the compounds is sufficient for creating a new crystal packing motif. We do find that reducing the symmetry of the axial group does increase the solubility greatly, however. We identify a new motif for BsubPc crystals that occurs when the intermolecular interactions between the axial phenoxy segment and the BsubPc ligand are increased. We present two methods for achieving this new motif, one is through addition of a π-Br interaction and the other is through creation of a strong π-acid/ π-base stacking by making the axial phenoxy more π-electron rich. Unfortunately, the p-bromophenoxy-BsubPc forms this new motif as a kinetic product, isolation of which is unreliable. Attaching a naphthol fragment axially to the BsubPc creates a stable version of this new motif. We also synthesized a new class of BsubPc pseudohalides based on sulfonate derivatives. Of the derivatives in this new class, we found that mesylate-BsubPc forms into a crystal packing structure that possesses a one-dimensional pathway for charge carrier mobility, but is still resistant to hydrolysis under the conditions tested. Overall, we show four compounds that meet the criteria for further study as organic electronic materials: p-methoxyphenoxy-BsubPc, α-naphthoxy-BsubPc, β-naphthoxy-BsubPc, and mesylate-BsubPc.

Dereliction of land by mining activities within the broad range of dereliction caused by other industrial and human activities was examined. Special attention was paid to impacts, mitigation, and costs thereof. Mine reclamation was examined in detail with special reference to professional interpretations. Mine reclamation bonding was studied with reference to environmental management planning so as to contribute to a forthcoming regulation concerning exactly these matters by providing a detailed listing of mining operations to be geared toward mine reclamation in Turkey&rsquo / s conditions and by providing key concepts in the inception of a draft regulation concerning mine reclamation as part of the EU accession program.

The main focus of this thesis is the characterization of defects and microstructure in high-energy ball milled magnesium hydride powder and magnesium-based multilayered composites. Enhancement in kinetics of hydrogen cycling in magnesium can be achieved by applying severe plastic deformation. A literature survey reveals that, due to extreme instability of -MgH2 in transmission electron microscope (TEM), the physical parameters that researchers have studied are limited to particle size and grain size. By utilizing a cryogenic TEM sample holder, we extended the stability time of the hydride phase during TEM characterization. Milling for only 30 minutes resulted in a significant enhancement in desorption kinetics. A subsequent annealing cycle under pressurized hydrogen reverted the kinetics to its initial sluggish state. Cryo-TEM analysis of the milled hydride revealed that mechanical milling induces deformation twinning in the hydride microstructure. Milling did not alter the thermodynamics of desorption. Twins can enhance the kinetics by acting as preferential locations for the heterogeneous nucleation of metallic magnesium. We also looked at the phase transformation characteristics of desorption in MgH2. By using energy-filtered TEM, we investigated the morphology of the phases in a partially desorbed state. Our observations prove that desorption phase transformation in MgH2 is of nucleation and growth type, with a substantial energy barrier for nucleation. This is contrary to the generally assumed core-shell structure in most of the simulation models for this system. We also tested the hydrogen storage cycling behavior of bulk centimeter-scale Mg-Ti and Mg-SS multilayer composites synthesized by accumulative roll-bonding. Addition of either phase (Ti or SS) allows the reversible hydrogen sorption at 350C, whereas identically roll-bonded pure magnesium cannot be absorbed. In the composites the first cycle of absorption (also called activation) kinetics improve with increased number of fold and roll (FR) operations. With increasing FR operations the distribution of the Ti phase is progressively refined, and the shape of the absorption curve no longer remains sigmoidal. Up to a point, increasing the loading amount of the second phase also accelerates the kinetics. Microscopy analysis performed on 1-2 wt.% hydrogen absorbed composites demonstrates that MgH2 formed exclusively on various heterogeneous nucleation sites. During activation, MgH2 nucleation occurred at the Mg-hard phase interfaces. On the subsequent absorption cycles, heterogeneous nucleation primarily occurred in the vicinity of internal free surfaces such as cracks. / Materials Engineering

This thesis employs experimental and theoretical methods to characterise carbon nitride solids and proposes a generalstructural model for amorphous carbon nitride (a-C:N). It finds that a-C:N deposited by several methods is essentially identical, with similar bonding environments for carbon and nitrogen atoms. Using evidence from several techniques, the saturation of nitrogen in an sp2 carbon matrix is discussed. The experimental studies on a range of carbon nitride solids show no evidence for a crystalline form of carbon nitride. In addition to the experimental characterisation of a-C:N, ab initio molecular dynamics were used to investigate bonding and structure in carbon nitride. These simulations show that the most common form of nitrogen bonding was three-fold sites with a lone pair of electrons. Two-fold nitrogen sites were also found in agreement with experimental findings. An increase of nitrogen in a-C:N decreases the sp3-carbon fraction, but this is not localised on the nitrogen and the effect is most severe at high densities. A simulation of a low density/high nitrogen content network shows that the nitrogen saturation seen experimentally may be due to the formation of N2 dimers and C-N molecules which are easily driven out of the structure. The ab initio simulations also explore the nature of charged nitrogen and carbon sites in a-C:N. An analysis based on Wannier Function centres provided further information about the bonding and allowed for a detailed classification of these sites. The removal of electrons from the networks caused structural changes that could explain the two-state conductivity in ta-C:N memory devices. Finally, a theoretical study of the electron energy-loss near-edge structure (ELNES) calculated using multiple scattering theory is presented. The calculated ELNES of diamond, graphite and boron, silicon and carbon nitride structures compare well to experiment and supports the experimental finding that no crystalline carbon nitride had (or has) been produced. These ELNES calculations will however, provide a means of identifying crystalline beta-C3N4 should it be synthesised.

Dissertation (Ph.D.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Title from first page of PDF file (viewed Feb. 16, 2009). Includes bibliographical references (p. 49-57).