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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.
1

Wave propagation in a rotating fluid of spherical configuration

London, Steven David, January 1976 (has links)
Thesis--Wisconsin. / Vita. Includes bibliographical references (leaves 197-198).
2

Some transformations of the complex plane corresponding to a rotation of the sphere in stereographic projection

Wierenga, Harold. January 1938 (has links)
Call number: LD2668 .T4 1938 W51 / Master of Science
3

Equal-area spherical maps for computer graphics. / CUHK electronic theses & dissertations collection

January 2007 (has links)
In this dissertation, we first introduce an equal-area spherical map, HEALPix, which is borrowed from astrophysics. Its associated sample pattern is uniformly distributed over the sphere surface. Then we discuss its application in environment mapping. Although the HEALPix representation is more balanced than the traditional cubemap, it cannot utilize the built-in hardware operations like cubemap, and the mipmapping construction is more complicated. Therefore, its rendering speed is not comparable to that of the cubemap. This motivates us to invent a new six-face spherical map, called isocube. Unlike cubemap, isocube is an equal-area mapping, i.e., each texel spans the same area and is equally important. Due to the six-face representation, isocube can fit nicely into the cubemap hardware and hence can fully exploit the hardware operations tailored for cubemap. In addition, its mapping computation only involves a small overhead. Therefore the look-up speed for isocube is very fast. / Next we discuss another application of HEALPix map, the dynamic environment sequence sampling. Previous work only considers the static case where the environment map is approximated by finite directional light sources. In the dynamic case, the individual regeneration of samples for each frame may introduce abrupt, changes in the rendering animation. To handle this temporal inconsistency problem, we propose spherical q2-tree based on IIEALPix map. The adaptiveness of the quadtree can suppress the abrupt changes between consecutive frames, and hence a rather smooth rendering can be produced. This method, however, generates sample pattern independently for each environment frame, and therefore it may still cause unexpected, lumps in some situations. To fully utilize the temporal coherence in the sequence, we present a global sampling approach which treats the dynamic environment sequence as a all volume and performs sampling in the volume. The volumetric sampling adapts the sample number according to each frame and restricts the temporal/spatial changes within small subdivided volumes, and hence ensures a smooth sampling sequence. Within the framework, we present a volumetric importance metric and develop a binary-quad tree to perform stratification. Experimental results show that our volumetric sampling method can generate light samples with a better temporal consistency. / Spherical map is the foundation for many applications in computer graphics, such as environment mapping, precomputed radiance transfer, radiosity and image-based rendering. For these applications that involve intensive computation on spherical domain, it is generally desirable to employ equal-area and uniform spherical maps as the underlying parameterization. However, equal-area spherical maps are less exploited in graphics. / Wan, Liang. / "August 2007." / Adviser: Tien-Tsin Wong. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1121. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 118-123). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.
4

Stereographic projection and mapping of engineering geology case study near Jordan Valley, Hong Kong /

Ho, Chiu-shek. January 2007 (has links)
Thesis (M. Sc.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.
5

Stereographic projection and mapping of engineering geology: case study near Jordan Valley, Hong Kong

Ho, Chiu-shek., 何照碩. January 2007 (has links)
published_or_final_version / abstract / Applied Geosciences / Master / Master of Science
6

Structural assessment of the Koulekoun Gold Deposit, Guinea, West Africa

Dopavogui, Joseph Siba January 2015 (has links)
The Koulekoun Gold project is the most important prospect of Avocet Mining plc. It is one of the projects within the TriK-block in Guinea (West Africa) for which an exploration permit has been granted. The Koulekoun deposit is located within the Siguiri basin of Birimian age in the Eastern Guinea region; where most Guinea’s gold mines are situated. The present study involves the investigation of structural elements (S₀, S₁, S₂, intrusive contacts, faults and veins) from selected drill cores from drill sections that intersect the Koulekoun orebody in four parts of the deposit; characterizes the principal orientations of measured structures and determines their relationships using stereonet; in order to predict important intersections to focus on in exploration programs within the TriK-block and suggests a possible structural model of the Koulekoun deposit. Raw data used for the present research was collected from half-core samples due to the absence of surface outcrop from which direct measurements could have been made. Measured data were interpreted using stereographic projection. Often no preferred orientations of structural elements exist in the area, suggesting a complex structural situation, particularly with regard to hydrothermal vein attitudes. Thus, it has been illustrated from structural data analysis and S₀ data 3d interpolation of the four sub-structural domains (North-East, North-West, Central and South) that NE-SW structures (S₂, intrusive contact, fault and vein) have controlled the occurrency of gold mineralization in the Koulekoun deposit area. Geometrical relationships between structure main cluster orientation from stereonet analysis show the majority of S₀ moderately E-dipping; intrusive contacts dip at moderate angle to the SE in all zones, except in the North-East zone where they are sub-vertical and SE-dipping. Fault planes show variable orientation of NE-SW, NW-SE and E-W, and steeply SE-dipping. Vein planes correspond to fault systems and show high variability in their orientation with numerous orders of vein direction in each domain. The cross-cutting relationships suggest two principal generations of faults: the NE-SW fault (F1) and the NW-SE fault (F2). These two fault systems and their associated vein intersection areas preferably define the ore shoot zones within the Koulekoun deposit. The proposed structural model of the Koulekoun deposit suggests the intersection and interference of major NW-SE and minor NE-SW structures. The interference of folds formed basin-dome structures with oval shape geometries striking NW-SE and that dominantly occur in North-East, North-West and Central zones. The South Zone is characterized by NE-SW gently plunging and moderately inclined folds with NW-SE striking axial surface. Gold mineralization occurs at the edges of basin-dome structures in North-East, North-West and Central zones. Mineralized porphyry intrusions are likely located within the axial surface of the South zone folds and extend toward the Central zone. The proposed model is compliant with the earlier model of the Koulekoun deposit presented by Tenova (2013); Fahey et al. (2013) describing the Koulekoun deposit as an auriferous NE-SW trending fault zone, intersecting a major NW-striking and steeply E-dipping porphyry units. The model also fits within the regional structural context suggested by Lahondere et al. (1999a) related to the E-W vein structures attributed to NW-SE fractures and to the conjugated fault of NE-SW direction. Comparatively to the three industrial gold deposits (Siguiri, Lero, Kiniero) being currently mined in the Siguiri Basin, and defined as mesothermal vein and lode mineralization hosted in Birimian meta-sedimentary rocks (Lalande, 2005), the Koulekoun gold deposit appears to be a porphyry hosted orogenic disseminated style mineralization system (Fahey et al., 2013). Although, similarities between the Koulekoun gold deposit and these three industrial deposits (Siguiri, Lero, Kiniero) constitute of the intensive extends of the weathering profile and at some stages, by the existence of numerous ring-shaped and curved lineaments enhanced by drag folding (Lero deposit for instance). It is therefore recommended that targets selection around the Koulekoun deposit and within the TriK-block for further exploration programs be concentrated along NW-SE structures, in objective to determine possible intersection zones with NE-SW structures.

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