The previously undifferentiated, "Melmoth Granite-Greenstone Remnant" (MGGR¹) crops out over an area of about 360 km² in northern Natal, South Africa. The greenstone sequence is comprised mainly of mafic metalavas with lesser serpentinite, talc schist, dacitic tuff, quartz-muscovite schist, quartzite and calc-silicate rocks. The greenstones are intruded by syntectonic trondhjemitic gneisses, late-tectonic granodioritic gneisses and post-tectonic granite dykes. Four phases of deformation and metamorphism are recognized. Epigenetic, disseminated and quartz vein-hosted gold mineralization is associated with D₂ shearing - a positive correlation existing between the intensity of the shearing, the thickness of the shear zone and the grade of ore it contains. Auriferous quartz veins are distinguished from an earlier generation of barren vein quartz on the basis of mineralogy, texture and relationship to the s-fabric. The mineralization occurs in zones of dilation associated with shear zone refraction. Associated wall rock alteration includes sericitization, argillization and chloritization. An ore genesis model based on the aforementioned parameters, is proposed. Finally, an exploration programme has been devised in order to locate undiscovered gold deposits in the MGGR. The programme could probably be applied, with minor modifications, to shear zone-hosted gold deposits in other granite-greenstone remnants in northern Natal. ¹- Name suggested by writer.

The North Caribou Greenstone Belt (NCGB) lies at the core the granitoid-dominant North Caribou Terrane (NCT). Two sedimentary assemblages; the Eyapamikama (ELS) and Zeemal-Heaton Lake (ZHA) form the core of the NCGB. Geochemistry of garnets from the orogenic Au deposit at Musselwhite suggest that the auriferous fluids have a contribution of metamorphic fluids and mineralization consisted of prolonged, multi-stage periods. Chemical zoning suggests changes in the influx of chalcophile and lithophile elements and that Au/sulphide ratios during nucleation were lower relative to later growth events. Zircons from the ELS and ZHA suggest a c. 100 My hiatus in the onset of sedimentation, with the ZHA showing younger, “Timiskaming-type” ages. Age distributions from each assemblage reflect proximal, igneous sources. Nd isotopic compositions of the ZHA suggest a mixture of ancient and contemporaneous sources which are similar to external TTG rocks. Deplete mantle model ages of the ZHA rocks indicate a Mesoarchean inheritance.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21070号 / 工博第4434号 / 新制||工||1689(附属図書館) / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 大村 善治, 教授 松尾 哲司, 准教授 小嶋 浩嗣 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

The feasibility of using oriented polymer technology in the design and manufacture of mechanical power transmission belts has been investigated. Working from an initial selection of polymers a die-drawing technique for orienting the polymers was devised, and the static and dynamic mechanical properties of the oriented polymers were investigated. These results indicated that PP, PBT, PPS and PEEK were suitable for further research. Of these 4 materials PBT was selected as the most appropriate material for belt manufacture based on cost, processability (drawing temperature, natural draw ratio) and limitations of laboratory equipment. A technique based on free-tensile drawing combined with simultaneous rotational motion was designed and used to manufacture oriented PBT flat belts from cylindrical injection moulded preforms. The technique used a tensile machine with two pulley-clamps, a fitted heated chamber and an electric motor to provide rotational motion to the belt during drawing. Two types of oriented PBT flat belts with different cross sections were produced successfully, termed 'thick' and 'thin'. These belts were tested on a purpose-built rig comprising two equal diameter pulleys, one driven by an electric motor and the other connected to a generator to provide load. The belt life and power transmission performance was investigated at various conditions of speed, transmitted torque and tension, and the results indicated that despite their smaller cross section 'thin' flat belts demonstrated up to 3 times longer life. However life was only 100 hours, which was very low compared with conventional flat belts that last for many thousands of hours at higher speeds and much greater power transmission capacity. Synchronous belts were then produced through the same manufacturing method used for flat belts. This aspect of the research concentrated on the initial pitch design and size, i. e. the timing. Initially a rectangular tooth profile was selected for its simplicity in terms of manufacture. The produced belts exhibited high pitch length variation as well as deformed teeth and were not usable for synchronous power transmission. An extra timing feature was included to control orientation; reducing the pitch length variation enabling consistent tooth production. It was observed that the areas between the extra timing feature and the tooth edges did not orient completely with some regions remaining undrawn. Finite Element Analysis (FEA) was used to predict the drawing behaviour of different shapes and dimensions of the timing features. The results suggested that a 4mm wide and 7mm long slot provided the highest possible extension and the minimum non-oriented regions on the groove. Whilst, the thickness and width of the drawn belt timing features showed differences to the FEA predictions, manufactured synchronous belts based on that design had much better controlled dimensions and the lowest achieved pitch length variation ( ±1%), compared to initial attempts. It is concluded that oriented polymers have the potential to be used in power transmission belts since they offer higher stiffness, tensile strength and creep resistance compared with isotropic polymers that are currently used in commercially available belts such as thermoplastic polyurethane (TPU) and polyvinyl chloride (PVC). The main disadvantages were the lack of dimensional stability and number of cycle to failure. / Polymer IRC; The University of Bradford; The Gates Corporation

<p> SE Botswana, located in the NW part of the Kaapvaal Craton is a long lived tectonically stable environment dominated by brittle deformation for more than 2.6 Ga. </p> <p> Relative chronologies in the development of fractures are rationalized according to major unconformities that developed during the Proterozoic in areas around Moshaneng and Kanye in SE Botswana. Periods of brittle deformation are divided into pre-Transvaal Supergroup, post-Transvaal Supergroup/ pre-Waterberg Group and post-Waterberg Group times. Pre-Transvaal lineaments trend ENE and NE and were probably formed as fractures in a rifting environment Dikes are intruded along some of these lineaments. Post-Transvaal/ pre-Waterberg fractures consist of strike-slip faults that form a conjugate system of two major sets trending NE and NW. These fractures probably formed as a result of E-W compression. The displacement along the NE trending faults depicts reactivation along pre-existing fractures. Regional patterns of fault termination are discemable. Epidermal folds and thrusts were produced in the Transvaal Supergroup rocks. Rotational bulk strain is locally significant. PostWaterberg deformation was dominated by dip-slip faults, vertical displacements and drape folds. </p> <p> An orthogonal system of bedding-normal joints predominates in the layered rocks. Inversion of the relative magnitudes of a2 and a3 probably accounts for a two phase tensile failure of layered rocks during the formation of the joint system. A diagonal system of bedding normal joints is superimposed on the orthogonal system possibly because of pre-existing folds that perturb the remote stress field. Joint spacings have a negatively skewed normal frequency distribution. Systematic joints show that spacing of set1 <set2 <set3 <set4. </p> <p> Relics of joint patterns in chert breccia provide insight about post-Transvaal/ pre-Waterberg karstification residuum. The joint pattern accounts for the initial process of fragmentation that resulted in the formation of chert breccia. </p> <p> On the subcontinental scale, high strain tectonic belts provide a chronology of large scale stress fields that could explain the intracratonic brittle deformations. </p> / Thesis / Doctor of Philosophy (PhD)

M. S.

Recent research on attempts to motivate large-scale safety belt use has documented a number of shortcoming, including limited long-term evaluation data, excessive costs, short-lived intervention effects, and program delivery by outside agencies rather than indigenous personnel. The present study attempted to overcome these disadvantages. Specifically, the "Buckle-up for Bucks" safety belt promotion campaign conducted at a community hospital incorporated the following: a) indigenous hospital staff as program sponsors, delivery agents, and co-coordinators; b) a year-long program evaluation; and c) a combination incentive and commitment-based intervention program. Directed and coordinated through the Office of Community Relations, the hospital-based intervention included awareness sessions, randomly determined five-dollar a week cash incentives, and a commitment-based pledge card strategy. To be eligible to win the incentives, the staff members met the following contingencies: a) wore a safety belt; b) signed a pledge card; c) displayed the signed pledge card on their dashboard; and d) pledged for a duration that ensured eligibility. The evaluation data were collected for four phases: baseline, intervention, withdrawal, and a long-term, follow-up. For the overall sample, usage increased from a baseline mean of 15.6% to 34.7% during the intervention, decreased to 25.6 at withdrawal, and increased to a long-term follow-up mean of 28.6%. For the Pledge card signers and the Non-singers, usage increased from baseline means of 29.4% and 11.8% to intervention usage rates of 75.1% and 17.7%, respectively, demonstrating that the intervention had a differential effect on the signers and non-signers. Withdrawal and Follow-up usage rates were 56.0% and 44.9% for the Pledge group, and 17.2% and 22.1% for the Non-pledge group. A chi-square test for white noise indicated the data were autocorrelated. A time-series analysis was conducted to remove the serial dependency. Statistical significance of the intervention was examined from the time-series perspective and traditional analysis of variance procedures. Differences between approaches are addressed and theoretical explanations for the intervention effects are considered. Finally, suggestions for future research are offered. / M.S.

The Archean (~3.0 Ga) Buhwa Greenstone Belt, and surrounding granite-gneiss terrane, is the least understood major greenstone belt in the Archean Zimbabwe Craton, despite occupying a critical position between an early Archean continental nucleus and the Limpopo Belt. The cover succession in the Buhwa Greenstone Belt, which was probably deposited on the margin of this nucleus, is divisible into shelfal and basinal facies associations separated by a transitional facies association. The shelfal association consists mostly of quartzarenite and shale, but also contains a thick succession of iron-formation. Geochemical characteristics of the shales indicate that the source terrane consisted of several lithologies including tonalite, mafic-ultramafic volcanic rocks, and granite that underwent intense chemical weathering. Basinal deposits consist dominantly of greenstones, with less abundant chert and ironformation. The cover succession, which was deposited on a stable shelf transitional to deep water, has no stratigraphic equivalents elsewhere on the Archean Zimbabwe Craton. However, time and lithologic correlatives in the central zone of the Limpopo The Archean (-3.0 Ga) Buhwa Greenstone Belt, and surrounding granite-gneiss terrane, is the least understood major greenstone belt in the Archean Zimbabwe Craton, despite occupying a critical position between an early Archean continental nucleus and the Limpopo Belt. The cover succession in the Buhwa Greenstone Belt, which was probably deposited on the margin of this nucleus, is divisible into shelfal and basinal facies associations separated by a transitional facies association. The shelfal association consists mostly of quartzarenite and shale, but also contains a thick succession of iron-formation. Geochemical characteristics of the shales indicate that the source terrane consisted of several lithologies including tonalite, mafic-ultramafic volcanic rocks, and granite that underwent intense chemical weathering. Basinal deposits consist dominantly of greenstones, with less abundant chert and ironformation. The cover succession, which was deposited on a stable shelf transitional to deep water, has no stratigraphic equivalents elsewhere on the Archean Zimbabwe Craton. However, time and lithologic correlatives in the central zone of the Limpopo ~2.9 Ga in southern Africa. At ~2.9 Ga, the northern margin of the greenstone belt experienced kilometerscale, oblique-slip dextral shearing. This shear zone and the surrounding margins of the greenstone belt were later intruded by the ~2.9 Ga Chipinda batholith, which ranges from granitic to tonalitic in composition. A number of events occurred during the time period spanning 2.9-2.5 Ga and current geochronology cannot separate their order; some are known to be coeval. Crustal shortening to the northwest, which resulted in map-scale folding of the cover succession (and surrounding batholith) and greenschist-facies metamorphism, occurred along a set of discrete high-angle reverse-sense shear zones in response to uplift the Northern Marginal Zone of the Limpopo Belt over the Zimbabwe Craton. Two suites of potassic granites were intruded into the area near the end of reverse shearing. Analysis of a conjugate fault pair that is developed within one of the potassic granite suites, yields a principal compressive stress consistent with continued northwest-directed crustal shortening. The region was stabilized by ~2.5 Ga, with intrusion of the Great Dyke of Zimbabwe. It is possible that the last events to affect the area, which include sinistral shearing, transecting cleavage development, and northwest-striking open folding, took place during the 2.9-2.5 Ga time intervaL These structures post-date regional folding and metamorphism, but because of limited magnitude and extent, do not show obvious cross-cutting relationships with other rocks or structures. A tenable alternative is that these late structures formed at ~2.0 Ga. an age that is proving to be of great significance in the evolution of the Limpopo Belt and along parts of the southern margin of the Zimbabwe Craton. / Ph. D.

Where can state, local and federal government officials concentrate their resources in order to reduce the highway fatality rate? A highway fatality model was developed to determine which factor has the greatest positive or negative impact on the highway fatality rate. A cross-section of data from states for 1984 and 1985 was collected for the following variables: average speed, speed variance, percentage of drivers wearing seat belts, percentage of licensed male drivers, percentage of drivers under 25 years of age, drinking age for beer, per capita alcohol consumption, percentage of urban population, and percentage of urban roads. The highway fatality equation was estimated via an iterative approach using ordinary least squares. The variables testing significant include: average speed, speed variance, drinking age for beer, percentage of drivers under 25 years of age, and percentage of urban roads. When translating the results into a policy action, it was determined that keeping the speed limit at 55 MPH on rural interstates would prevent the greatest number of traffic fatalities. Other policy actions considered in order of their impact on highway fatalities include: more stringent enforcement of the 55 MPH speed limit, restricting teenage night-time driving, raising the driving age to 17 years of age, and raising the drinking age for beer to 21 in the seven remaining states. / M.A.

A pledge card program designed to motivate safety belt use was implemented at a Baptist church in Blacksburg, Virginia. The intervention consisted of an educational insert and pledge card which were included in church bulletins on one Sunday morning. The insert described the risk of injury on highways and added a prompt for parents to provide positive role models for their children by wearing safety belts. The pledge card included a statement that signers would buckle their safety belts for four weeks when traveling. Data were collected at predetermined time periods on Sunday mornings between January 29 and May 20, 1984. The study consisted of five phases: Unannounced Baseline, Announced Baseline, Pledge Period, Follow-Up, and Long-Term Follow-Up. Ten percent of 441 individuals attending church when the pledge cards were distributed signed and returned a pledge card. Results revealed that shoulder belt use of pledge card signers increased significantly after signing the pledge cards, while shoulder belt use of non-signers did not significantly increase. In addition, shoulder belt usage of females was significantly higher than shoulder belt usage of males following the announcement of the research and throughout the remainder of the study. Evidence of participant reactivity is also presented. Suggestions are made for mitigating reactivity, for achieving greater impact on males, and for motivating more males and females to sign pledge cards. / Master of Science