Thesis (Ph. D.)--University of Oklahoma, 1997. / Includes bibliographical references (leaves 135-144).

Thesis (Ph. D.)--University of Oklahoma, 1999. / Includes bibliographical references (leaves 184-194).

This thesis provides an overview of identifying the Intertropical Convergence Zone (ITCZ) in the Middle East and North Africa (MENA) region. The ITCZ is a zone of wind convergence around the equator that coincides with an area of intense precipitation that is commonly termed a tropical rainbelt. In Africa, these two concepts are frequently confounded. This work studies the correlation between precipitation and commonly used ITCZ indicators. A further attempt is made to detect movement in the African ITCZ, based on earlier paleontological studies showing historical changes in precipitation. Zonally averaged wind convergence is found to be the most reliable indicator of the African ITCZ, one having a low correlation with zonally averaged precipitation. Precipitation is found only to be a reliable indicator for the African ITCZ in zones near the wind convergence, which reaches as far north as 20_N in the summer. No secular change in location of the African ITCZ is found for the time of available data. Finally, historical data shows that any increase in precipitation in the Sahel, a region where precipitation is driven by the ITCZ, is mildly negatively correlated with precipitation in the rainbelt area, suggesting that shifts in the ITCZ result in a widening of the precipitation profile as well as a shift of the entire zone.

No description available.

No description available.

No description available.

The precipitation and crystallization of aluminum (oxy)hydroxides from chloride solutions by neutralization appears to be quite complex and depends on several parameters, namely, temperature, the OH/Al molar ratio, aging and solution composition. The precipitation of aluminum from AlC13 solutions was found to be complete at substoichiometric OH/Al ratios (typically ~ 2.7), and resulted in the production of an amorphous material that transformed to crystalline phases upon aging at OH/Al ≥3. The predominant phases precipitated from 0.5M AlCl3 solutions at 22, 60 and 95° C at an OH/Al ratio of 3 after 24 hours of aging were pseudoboehmite, bayerite and boehmite, respectively. Increasing the OH/Al ratio and aging time at both 22°C and 60°C promoted crystallization of bayerite over poorly crystalline boehmite. At 95°C, regardless of aging time or degree of neutralization, boehmite was consistently obtained. Increasing the AlCl3 concentration to 2.0M proved to suppress the crystallization of bayerite at 22°C and 60°C, and favoured the crystallization of pseudoboehmite instead. Between the bayerite and pseudoboehmite products, the former exhibited the best settling behaviour (30% settled slurry density after 1 week), while settling did not occur at all for the latter. / Precipitates produced from mixed AlCl3-NaCl solutions exhibited an increasing tendency to form pseudoboehmite over bayerite with increasing sodium chloride concentration. Upon neutralizing mixed AlCl3-MgCl 2 systems, the final solution pH decreased significantly with increasing magnesium chloride concentration. Furthermore, increasing concentrations of MgCl2 promoted the precipitation of poorly crystalline mixed magnesium-aluminum-hydroxide hydrates, identified as Mg6Al2(OH)18·4.5H 2O by XRD. Increases in temperature (up to 125°C), aging time (48 hours) and OH/Al ratio (3.45) were unsuccessful in improving the crystallinity or transformation of these precipitates.

No description available.

Stress relaxation measurements were carried out on a plain carbon and four Ti steels over the temperature range 850 to 1050$ sp circ$C. The results show that the stress relaxation of plain carbon austenite after a 5% prestrain can be described by the relation $ sigma$ = $ sigma sb0$-$ alpha$ln(1 + $ beta$t). By contrast, in the solution-treated Ti steels, relaxation is arrested at the start of precipitation and is resumed when precipitation is complete. As a result, this new mechanical method is suitable for following carbonitride precipitation in microalloyed austenite at hot working temperatures. / PTT diagrams were determined by the present technique for the steels containing 0.05, 0.11, 0.18 and 0.25% Ti. The PTT curves obtained are C shaped for all the steels. The upper parts of these curves are shifted to significantly longer times as the Ti and C concentrations are reduced. By contrast, the positions of the lower arms of the curves are relatively independent of the current values of the solubility product (Ti) (C). This phenomenon is attributed to the catalytic effect of trace amounts of dissolved N on the nucleation rate of Ti(CN) in austenite. / Changes in the size distribution and morphology of the precipitates during relaxation of the 0.25% Ti steel were followed by means of electron microscopy. The cube shaped Ti(CN) precipitates were heterogeneously distributed in either a chain-like or a cell-like manner. Electron microanalysis was additionally carried out to determine the compositions of the Ti carbosulphide-Mn sulphide inclusions. / Finally, the experimental results are compared with the predictions of classical nucleation theory and of the diffusion controlled particle growth theory. Good agreement was obtained between the predictions of the theories and the experimental results. It is demonstrated by means of the thermodynamic analysis of nucleation that the Ti(CN) precipitate/austenite interface is of a semi-coherent nature. It is shown that the interface between a critical nucleus and the matrix can be characterized by the newly introduced coherency loss parameter C.

Introduktion: Partnervåld är ett världsomfattande problem som drabbar både män och kvinnor. Manliga brottsoffer uppfattas som mer ansvariga för våldet de utsätts för än kvinnliga brottsoffer och uppfattningarna får konsekvenser för bemötande inom rättsväsendet och vilken hjälp brottsoffret får. Syfte: Att undersöka skillnader och likheter i studenters uppfattningar om brottsoffers delaktighet till sin utsatthet för partnervåld i heterosexuella parrelationer. Vidare var syftet med studien att undersöka hur studenternas rekommenderade åtgärder efter en inträffad partnervåldsincident skiljer sig mellan manligt respektive kvinnligt brottsoffer. Metod: En enkätstudie genomfördes på Mittuniversitetet i Sundsvall, där 90 studenter fick läsa om ett manligt brottsoffer och 88 studenter fick läsa om ett kvinnligt brottsoffer. Enkäten bestod av åtta fallbeskrivningar med tre frågor till respektive fallbeskrivning. Grupperna som jämfördes var manliga och kvinnliga respondenter samt respondenter som läst om ett manligt respektive kvinnligt brottsoffer. Dataanalysen utfördes i statistikprogrammet SPSS. Resultat: Manliga brottsoffer uppfattades som mer delaktiga till sin utsatthet än kvinnliga brottsoffer. Både manliga och kvinnliga brottsoffer uppfattades som mer delaktiga till sin utsatthet av manliga respondenter jämfört med kvinnliga respondenter. Respondenterna tenderade att uppfatta brottsoffer som mer delaktiga till sin utsatthet vid aktiv precipitation än vid passiv precipitation. Kvinnliga brottsoffer blev i högre utsträckning än manliga brottsoffer R rekommenderade att kontakta polisen efter inträffad partnervåldsincident. Diskussion: Manliga och kvinnliga brottsoffer uppfattas olika trots identiska partnervåldsincidenter. Detta går i linje med tidigare forskning som förklarar skillnaderna med könsstereotyper inom partnervåld. Resultatet är av vikt för arbetet med brottsoffer för partnervåld då uppfattningar om brottsoffers delaktighet till sin utsatthet kan påverka hur individer bemöter brottsoffer för partnervåld. / <p>2015-06-03</p>