No description available.

The thesis is a study of how architecture brings the fantasy from drawings to the reality as a building. A library is a good choice for me because of the most familiar experience that accompanied with me so far is learning. The key of a library, in this case, should be "sharing the knowledge", it will from book, discovery and discussion. / Master of Architecture

A Dissertation submitted to the Faculty of Science, University of the Witwatersrand; in fulfilment of the requirements for the degree of Master of Science. Johannesburg August 2016. / Rocks of the Neoarchaean Witwatersrand Supergroup exposed in the collar of the impact-induced 2.02 Ga Vredefort Dome exhibit complex geological structures. These structures are generally considered to have been formed by the Vredefort impact event, through rapid deformations on time scales of seconds to minutes associated with the relatively brief impact processes. However, geological mapping of the structures and petrographic analysis from the northern collar of the dome show that the collar hosts at least three generations of pre-impact structures. In contrast to impact-induced structures, these pre-impact structures indicate slow and progressive deformations that are uncharacteristic of impacts. The pre-impact deformations comprise: (a) an extensional D1 deformation characterised by listric faults up to kilometre-scale; (b) Syn-metamorphic (M2(NC)) D2 ductile deformation characterised by regional S2 foliation, which locally indicates northwest-directed vergence; and (c) D3 deformation that crenulated the pre-existing S2 foliation (S3). Pre-impact structures can be distinguished from impact-induced structures by: (1) difference in the geometry and sense of slip between D1 faults and D4 impact-induced faults; and (2) crosscutting relationships between impact-induced D4 features and D2 and D3 pre-impact features. In their present (rotated) orientation, the D1 faults exhibit an apparent strike-slip separation, which translates to normal-slip fault geometries when impact-induced overturning of strata is undone. Displacement affects the Witwatersrand and Ventersdorp Supergroup rocks but no offset is observed of the base of the Transvaal Supergroup. The faults also exhibit a listric geometry, curving into parallelism with bedding in the lower West Rand Group. In their restored orientation, faults define half-graben and horst blocks, synthetic and antithetic faults, and rollover and drag folds, which are typical for extensional tectonics. These geometries and crosscutting relationships of the D1 faults are similar to that of the Neoarchaean listric faults described in the Witwatersrand goldfields and the wider Kaapvaal craton, that exhibit a general west-side-down sense of slip (2.70-2.64 Ga Hlukana-Platberg extensional event). Metamorphic grade in the study area decreases from amphibolite- to greenschist-facies away from the centre of the dome. These are largely M2(NC) metamorphic assemblages that are attributed to elevated regional heat flow related to 2.06 Ga Bushveld magmatism. There is some evidence that M2(NC) metamorphic mineral assemblages developed along the same stratigraphic units differ across the large D1 faults, indicating the pre-impact nature of the D1 faults and implying that the M2(NC) metamorphism occurred after the Hlukana-Platberg event. Also, M2(NC) assemblages are syn-tectonic to the S2 foliation hosted in metapelite units of the West Rand Group and knotted quartzite horizons of the Central Rand Group. The S2 foliation is attributed to the post-Transvaal Supergroup, compressional, Ukubambana Event. Crosscutting relationships in the study area indicate a deformational period of 2.06 Ga to no less than 2.02 Ga. The northwest-directed vergence exhibited by the S2 foliation is broadly consistent with the regional, general north-directed, vergence exhibited by post-Transvaal Supergroup foliation developed in the northeastern collar and the Johannesburg Dome. The S2 foliation and M2(NC) mineral assemblages are crosscut by D4 pseudotachylitic breccia, micro-faults and kinks, and M4(NC) metamorphic features associated with the impact. / LG2017

No description available.

MSc, Faculty of Science, University of the Witwatersrand, 1999

The numerous studies on the effects of patch size on bird assemblages have produced varied results. I studied the effects of patch size and surrounding matrix on bird assemblages within central Florida cypress domes. My null hypothesis was that bird assemblages within cypress domes are unaffected by dome size or development in the matrix around the dome. My alternative hypothesis was that differences in bird assemblages are correlated with size and the degree of development within the matrix. I classified a pool of over a thousand domes according to three size categories and four matrix types. Three representatives for each combination of size and matrix were spot mapped for birds from May through August 2005. I examined the relationship of species richness and bird guilds to patch size and surrounding matrix. I also measured a series of potential covariates for each dome to account for variation among the three size-matrix representatives for each combination. Richness and abundance counts were divided by the number of listening points to standardize the data by effort. I found that the standardized species richness of bird assemblages significantly increased with the patch size of cypress domes; however, matrix and the interaction effect of size and matrix on overall standardized species richness were not significant. Significant covariates included percent of the buffer undeveloped, percent herbaceous cover, and the number of listening points per unit area. A linear regression tested for significant effects of log area and matrix on standardized species richness. Matrix was not significant, but log area did have a significant effect on standardized species richness. The MANOVA tests for guild richness data indicated no significant effects of dome size, matrix, or their interaction effect on diet, foraging, or location guilds. There were no significant main or interaction effects on any individual guilds in the ANOVA output. Individual backward linear regressions done on each guild indicated that matrix did not have significant effects on any guild, but log area had significant effects on ground foragers, lower-canopy foragers, omnivores, herbivores, and edge species. I then investigated the effects of size and matrix on standardized guild abundance. Dome size and matrix significantly effected diet guild abundance, but the size-matrix interaction did not. Dome size significantly affected insectivores, omnivores, and carnivores. Matrix had a significant effect on omnivores, herbivores, and carnivores. The size and matrix interaction had a significant effect on carnivores. Dome size and matrix significantly affected foraging guild abundance, but the size-matrix interaction did not. Dome size significantly affected ground, lower- and upper-canopy foragers. Matrix had a significant effect on ground, water, and upper-canopy foragers. The size and matrix interaction was not significant for any foraging guild. Dome size and matrix significantly effected location guild abundance, but the size-matrix interaction did not. Dome size significantly affected edge and interior species. Matrix had a significant effect on edge and interior species. The size and matrix interaction was not significant for any location guild. The relationship between species richness and habitat area is well-documented, and the results of this study were consistent with the expectation of higher species richness in larger areas. If maintaining high species richness is the sole goal of conservationists, then large habitat fragments would be preferable regardless of surrounding matrix. Nevertheless, species richness alone is not informative of the potential effects of patch size and matrix on the composition of an avian assemblage. Guild analysis gives insight into community structure and should be considered in addition to simple measures of species richness. Patch size and matrix type significantly affected a number of guilds, and several factors could contribute to the observed differences in guilds across patch size categories and matrix types. Different habitats are available to birds in domes of each size class and matrix type. The potential for diverse foraging opportunities increases as domes increase in size and change in relation to their surrounding matrix. A more detailed analysis is needed to determine how differences in vegetation of domes and surrounding matrix affect guilds, members of which may use habitats both within domes and the matrix. Cypress domes in the central Florida area face severe alteration or destruction due to rapid development. Long-term research that focuses on domes before and after development is needed to understand how changes in the matrix or size of the domes affect all resident flora and fauna. A variety of taxa and biogeochemical processes should be researched. Domes are naturally highly variable in size, shape, and structure, and development changes all of these characteristics. Conservation biologists and managers urgently need to determine how development affects cypress domes and what can be done to maintain their characteristic biodiversity.

This thesis aims at creating a dome fabricated from pattern and studying some of the forms of patterns that focus on organistic pattern. / Master of Architecture

The design of several variants of the structure of the planetarium in Brno is the subject of the diploma thesis . The building has a ground plan size of 30x30 meters. The main supporting material is S235 steel. The bearing structure of the object consists of columns, joists and beams. The bearing structure of the dome consists of a spatial structure, which is formed as a half-globe above the diameter of 18 meters. 3 versions of this dome have been processed. The resulting design is Geodetic Dome. Part of the work is an assessment of the main structural elements and selected details. The Scia engineer 2016 version 16.1.3033 was used to calculate internal forces.

Abstract Geochemical, microstructural and petrological analyses were conducted on metapelites from the Strafford Dome, Vermont. Samples record metamorphic conditions from biotite to peak kyanite/staurolite grade and preserve microstructures related to two Acadian nappe emplacement events. The purpose of this study was to test the validity and application of the Ti-in-quartz (“TitaniQ”) thermobarometer to constraining pressure-temperature-timing-deformation (P-T-t-D) paths in metamorphic tectonites. Due to the nearly ubiquitous presence of quartz in continental rocks, the ability to apply this method would have significant implications for improving our ability to resolve tectonic histories. Cathodoluminescence (CL) imaging on quartz was conducted to qualitatively assess the distribution of Ti in a single grain and/or compare neighboring crystals. X-ray mapping of garnet porphyroblasts was conducted to estimate P-T conditions during garnet growth to provide a framework for included quartz grains. P-T-X contour diagrams (used in P-T calculations for garnet growth) were constructed from data obtained by X-ray fluorescence analysis on bulk-rock chemistries. Secondary ion mass spectrometry analysis was conducted to constrain Ti concentrations in quartz due to the low [Ti] present in the Strafford samples (<10 ppm). Analysis of the samples revealed [Ti] in zoned quartz grains that can be grouped and associated with certain P-T-D conditions. A majority of quartz grains have dark cores in CL images with low [Ti] (~2.5–3.5 ppm) in both matrix quartz and inclusions. Quartz inclusions in garnets that grew syn-tectonically with D2 have bright rims ~5.5 ppm. Matrix quartz, on the other hand, has rims with much higher [Ti] (~7.5–9.5 ppm). Comparing these Ti concentrations to summary P-T paths from previous studies suggests: quartz inclusions have rims recrystallized during the end of D1 deformation, matrix grains have rims re-equilibrated at peak P-T conditions post-D2 deformation, and the dark cores observed in CL images must be from early prograde or relics of the protolith. The evaluation of the TitaniQ thermobarometer’s application to constrain P-T-t-D histories has highlighted some potential problems and significant benefits. To use the thermobarometer, either T or P must be independently constrained, which is often difficult to do given the many microstructural contexts of quartz in a single sample. This study capitalized on the ability to determine the relative timing of quartz (re)crystallization relative to garnet growth. Using another trace element thermobarometer would be ideal (e.g. Zr-in-rutile) for greater precision, although the relevant accessory phases may not be present and constraining the timing of re-equilibration is challenging. The abundance of quartz in continental rocks and the various microstructural occurrences of quartz in a single metamorphic tectonite provides additional opportunities to constrain points on the P-T-D path than conventional thermobarometers. The TitaniQ thermobarometer has the potential to yield deeper insights into the tectonic history of crustal rocks than previously available. These findings further elucidate the potential of the method for use in studies of metamorphic tectonites, continental tectonics and rheology.

The Vredefort Dome is located southwest of Johannesburg, South Africa, and represents the deeply eroded remnant of the central uplift of the world’s largest known impact structure, with an estimated diameter of ~300 km. The Vredefort impact structure is also the oldest known impact structure on Earth (~2.02 Ga). The Vredefort Dome comprises an ~40 km wide core of Archaean basement gneisses and an ~20 km wide collar of subvertical to overturned Late Archaean to Palaeoproterozoic supracrustal strata. This project presents the results of Landsat-TM and aerial photograph analysis, as well as field mapping of Witwatersrand Supergroup metasedimentary strata in the collar of the Vredefort Dome. The aim of this study was to investigate the structures (such as folds, faults, fractures), at all scales, and other deformation features (such as shatter cones and pseudotachylitic breccias) in the field area, and to establish geometric and temporal relationships between these features with regard to the impact cratering process. This study revealed a highly heterogeneous internal structure of the collar involving folds, faults, fractures and melt breccias that are interpreted as the product of shock deformation and central uplift formation during the Vredefort impact event. Broadly radially-oriented symmetric and asymmetric folds, with wavelengths from tens of metres to kilometres, and conjugate radial to oblique faults with strike-slip displacements of, typically, tens to hundreds of metres accommodated tangential shortening of the collar of the dome that decreased from ~17 %, at a radial distance from the dome centre of 21 km, to <5 % at a radial distance of 29 km. Ubiquitous shear fractures containing pseudotachylitic breccia, particularly in the metapelitic units, display variable local slip senses consistent with either tangential shortening or tangential extension; however, it is uncertain whether they formed at the same time as the larger faults during the rise of the central uplift or earlier, during the shock compression phase of cratering. Contrary to the findings about shatter cones of some earlier workers in the Vredefort structure, the Vredefort cone fractures do not show uniform apex orientations at any given outcrop, nor do small cones show a pattern consistent with the previously postulated “master cone” concept. The model of simple back-rotation of the strata to a horizontal pre-impact position also does not lead to a uniform centripetal-upward orientation of the cone apices. Striation patterns on the cone surfaces are variable, ranging from typically diverging, i.e., branching off the cone apex, to subparallel to parallel on almost flat surfaces. Striation angles on shatter cones do not increase with distance from the crater centre, as suggested previously. Instead, individual outcrops present a range of such striation angles, and a more irregular distribution of striation angle values with regard to the distance from the crater centre suggests localised controls involving the nature and shape of various heterogeneities in the target rock on this aspect of cone morphology. On the basis of the observations made during this study on small-scale structures in the collar of the Vredefort Dome, the relationship of shatter cones with curviplanar fractures (multipli-striated joint sets - MSJS) is confirmed. Pervasive, metre-scale tensile fractures crosscut shatter cones and appear to have formed after the closely-spaced MSJ-type fractures. The results of this study indicate that none of the existing models is able to explain all characteristics of shatter cones fully; therefore, a combination of aspects of the different models may currently be the best possible way to explain the formation and origin of shatter cones, and the formation of the related MSJ and their characteristic aspects (e.g., curviplanar shape, melt formation, etc.). The observed variety of shatter cone orientations, surface morphology and striation geometry in the dome concurs broadly with the results of some previous studies. The abundance of striated surfaces along closely-spaced sets of fractures (MSJ) observed in this study can be reconciled with reflection/scattering of a fast propagating wave at heterogeneities in the target rocks, as proposed by recent studies. This would mean that closely-spaced fractures and shatter cones were not formed during shock compression, as widely postulated in the past, but immediately after the passage of the shock wave, by the interference of the scattered elastic wave and the tensional hoop stress that develops behind the shock front. In addition to shatter cones, quartzite units show two other fracture types – a centimetre-spaced rhomboidal to orthogonal type that may be the product of shock-induced deformation and related to the formation of shatter cones, and later joints accomplishing tangential and radial extension. The occurrence of pseudotachylitic breccia within some of these later joints confirms the general impact timing of these features. Pseudotachylitic breccias in the collar rocks occur as up to several centimetre-wide veins with variable orientations to the bedding and as more voluminous pods and networks in zones of structural complexity, such as the hinges of large-scale folds and along large-scale faults, as well as locally, at lithological interfaces. In places, tension gash arrays along thin veins are observed indicating that movement occurred along these planes. Initial cooling calculations for pseudotachylitic breccias of different widths and compositions (metapelite or quartzite) suggest that thick veins (<10 cm) could have stayed molten over the entire duration of crater development (at least 10 minutes), making it possible for shock-induced melts to intrude dilational sites, such as fold hinges and extensional fractures, during the formation and subsequent collapse of the central uplift. Intrusion of such melts may also have lubricated movements along brittle and ductile structures. Thus, the presence of both shock- and friction-generated melts is likely in the collar of the Vredefort Dome. Based on the spatial and geometric relationship between the structures and other deformation features observed in the collar rocks of the Vredefort Dome, it is possible to establish a temporal sequence of deformation events. Shatter cones and related closely-spaced fractures were formed during the contact/compression phase of the cratering process. The formation of at least some shock-induced pseudotachylitic breccia also belongs into this phase. Large-scale folds and faults and friction-generated melts can be related to the initial formation of the central uplift and extensional joints to the subsequent collapse of the central uplift.