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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.
161

Target selection from airborne magnetic and radiometric data in Steinhausen area, Namibia

Naudé, Corus 09 November 2012 (has links)
The eastern branch of the late Proterozoic Damara Orogenic Belt of central Namibia hosts various copper, gold, manganese and uranium deposits, but in the vicinity of Steinhausen, approximately 145 km northeast of Windhoek, the Damara Belt becomes increasingly covered by recent Kalahari cover sediments resulting in little known geology and subsequent lack of discovered economic mineral deposits. Airborne magnetic and radiometric data over the Steinhausen Study Area was enhanced through image processing and filtering to accentuate characteristics of subsurface geology that, by comparing these characteristics to known geology, aided in the interpretive mapping of lithology, structure and targets for follow-up exploration. As a result, some important observations regarding the regional lithology can be drawn. An arenaceous stratigraphic unit that includes a coarse grained, glassy quartzite below the Kuiseb Formation equates to either the eastern Damaran equivalent of the Nosib Group subjected to high grade metamorphism or, alternatively, the upper part of the pre-Damaran sequence, immediately underlying the Damara. The Kuiseb Formation within the study area is uncharacteristically varied as compared to the same formation further west along the Damaran Orogen and can be subdivided into 5 separate units based on geophysical signature. Structural features evident within the study area include the prominent Kudu and Okahandja Lineaments and straddle an area of inferred uplifted stratigraphy of possibly pre-Damara age. The Ekuja Dome (Kibaran age and host to the Omitiomire copper deposit) is also clearly discernible on the airborne magnetic data and is cross-cut by an east-northeast structural zone. Direct targets for follow-up exploration include the Rodenbeck intrusion, anomalous magnetic bodies and numerous radiometric anomalies present within the study area. Identified dome-like features are considered prospective for Omitiomire-style deposits and the Okatjuru Layered Complex is considered a possible source of copper, chromite, magnetite, ilmenite, nickel and the platinum group elements.
162

Integration of borehole and seismic data to unravel complex stratigraphy : case studies from the Mannville Group, western Canada

Sarzalejo de Bauduhin, Sabrina, 1955- January 2009 (has links)
No description available.
163

An integrated geophysical program for sulfide exploration at Ham Nord, Quebec/

Jihad, Abakoyas January 1974 (has links)
No description available.
164

Borehole geophysics limitations of natural gamma and gamma-gamma density logging methods

Tsang, Wing-shing., 曾永成. January 2003 (has links)
published_or_final_version / Applied Geosciences / Master / Master of Science
165

Electrical methods surveys in southern Arizona for hydrogeological investigations

Didi, Didace, 1952- January 1990 (has links)
The central induction TEM and CSAMT strengths and weaknesses were analyzed at the San Xavier geophysical test site. TEM results indicate that the depth of investigation of the TEM sounding data is limited by the noise level. CSAMT data are contaminated by static shift effects due to shallow geological inhomogeneities or topography. CSAMT data are also contaminated by the transmitter overprint which depends on the geology beneath the transmitter dipole and the receiving stations. In the Miami Wash-Pinal Creek area of Arizona, where the groundwater contamination was to be studied by electrical methods, the complex resistivity method was first used. Results in the Miami Wash-Pinal Creek area show a trend which consists of a high-low-high trend in the resistivity/I.P. curves for soundings located in the contaminated zone and of an increase of the I.P. curve in the uncontaminated zone.
166

Magnetometry for archaeologists

Aspinall, A., Gaffney, C. F., Schmidt, Armin January 2009 (has links)
No description available.
167

Integrated geophysical-geochemical methods for archaeological prospecting

Persson, Kjell January 2005 (has links)
A great number of field measurements with different methods and instruments were conducted in attempts to develop a method for an optimal combination of various geochemical and geophysical methods in archaeological prospecting. The research presented in this thesis focuses on a study of how different anthropogenic changes in the ground can be detected by geochemical and geophysical mapping and how the results can be presented. A six-year pilot project, Svealand in Vendel and Viking periods (SIV), was the beginning of this work in which EM- measurements, gradiometer and GPR surveys together with phosphate mapping succeeded in detecting settlements, mainly from the Iron Age. During the project, a new field kit for soil phosphate analysis was also developed and patented. Another major project was the examination of the Kings’ Mounds in Old Uppsala where a multi method survey including two different slingrams, three different types of GPR equipments and two different gradiometers was used for detecting structures inside the mounds. The Thing Mound was interpreted not to be a burial mound. The layers indicated by the GPR survey are most probably natural glaciofluvial layers. At the Eastern Mound the measurements detected an excavation tunnel from 1846-47, some known old brick furnaces from the time of building of the church, the original esker surface and the central cairn. The survey also detected two linear structures from the mounds base to the top and a depression under the mound in the old esker. The linear structures were interpreted as possible boulder rows and the depression as a possible older burial preceding the construction of the mound. Other surveys with slingram and GPR were used to detect subsurface features at historical gardens and historical glass works. A number of surveys to detect older church remnants were also carried out. In a project at Arethousa, Greek Macedonia, slingram measurements pointed out possible subsurface stonewalls and a possible hearth, which were confirmed later by excavations. At Old Uppsala, Sweden a GPR survey was successfully used for detecting the older cathedral under the present church. The overall results led to a recommended concept of combined methods for archaeological prospecting, especially in northern Europe. Slingram measurements of both electrical and magnetic components combined with phosphate mapping and GPR surveys proved to be useful methods for such prospecting.
168

A Computer Algorithm for Synthetic Seismograms

Isaacson, James 08 1900 (has links)
Synthetic seismograms are a computer-generated aid in the search for hydrocarbons. Heretofore the solution has been done by z-transforms. This thesis presents a solution based on the method of finite differences. The resulting algorithm is fast and compact. The method is applied to three variations of the problem, all three are reduced to the same approximating equation, which is shown to be optimal, in that grid refinement does not change it. Two types of algorithms are derived from the equation. The number of obvious multiplications, additions and subtractions of each is analyzed. Critical section of each requires one multiplication, two additions and two subtractions. Four sample synthetic seismograms are shown. Implementation of the new algorithm runs twice as fast as previous computer program.
169

Resource Utilization of Salespeople and Prospecting Performance

Nguyen, Thuy D. 12 1900 (has links)
Every day, salespeople span boundaries, coordinate internal and external expertise, leverage social capital, mobilize the tangible and intangible resources of their firm, and try to create value for all stakeholders. Recognizing the important roles of salespeople, Evans et al. (2012) and Lassk et al. (2012) call for more research on the usage of skills, knowledge, people, strategies, expertise, and other resources of salespeople to produce the desired outcomes. Responding to their calls, this study specifically focuses on how salespeople utilize their available and finite resources across four types of customers (new customers, short term customers, long term customers, and win-back customers) to identify and qualify new sales opportunities during the prospecting stage. The dissertation focuses on seven types of resources (capturing both internal and firm related resources) available for salespeople: (1) firm tangible, (2) firm intangible, (3) firm market based, (4) present resources, (5) skills, (6) knowledge, and (7) accumulated successes. The study further explores the moderating roles of organizational identification, competitive intensity, and customer dependence on the relationship between resources utilized and performance during the prospecting stage. The resource utilization scale is developed and tested for robustness. Next, using a final dataset of 346 responses from salespeople, the results reveal that salespeople adaptively utilized various resources across new customers, short-term customers, long-term customers, and win-back (lost) customers. Overall, performance during prospecting stage are more strongly influenced by utilization of internal resources (presence, knowledge, skills and success) than firm related factors. Further, successful prospecting performance requires the usage of skills and knowledge resources with new customers, only skills resources with short-term and long-term customers, but present resources, knowledge, and firm tangible resources with win-back customers. In addition, organizational identification and competitive intensity moderate the relationship between resource utilization and prospecting performance for all customer types, whereas customer dependence is an important moderator for long-term customers. The paper makes several contributions to key areas such as resource allocations in the context of personal selling, and how firms can strategically enhance the performance of their salespeople. Theoretically, the study develops resource utilization scale, and empirically tests its effects on prospecting performance. From a managerial stand point, this dissertation offers additional insights into the effectiveness of each type of resources to plan for selective development of resources, as well as focused sales training.
170

Borehole electromagnetic prospecting for weak conductors

Theodoridis, John Apostolis, 1972- January 2004 (has links)
Abstract not available

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