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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.
81

Processing and analysis of seismic reflection and transient electromagnetic data for kimberlite exploration in the Mackenzie Valley, NT

Moore, David Anton 05 1900 (has links)
The Lena West property near Lac des Bois, NT, held by Diamondex Resources Ltd., is an area of interest for exploration for kimberlitic features. In 2005, Frontier Geosciences Inc. was contracted to carry out seismic reflection and time-domain transient electromagnetic (TEM) surveys to investigate the possibility of kimberlite pipes being the cause of total magnetic intensity (TMI) anomalies previously identified on the property. One small part of the property, Area 1915, was surveyed with two perpendicular seismic reflection lines 1550 m and 1790 m long and three TEM lines consisting of six or seven individual soundings each with a 200 m transmitter loop. The results generated by Frontier Geosciences did not indicate any obvious vertical features that correlated with the TMI anomaly. The purpose of this study is to reprocess the seismic reflection data using different approaches than those of Frontier Geosciences and to invert the TEM data using a 1-D inversion code, EM1DTM recently developed by the UBC Geophysical Inversion Facility, to improve upon previous results and enhance the interpretation. A secondary objective is to test the robustness of EM1DTM when applied to observed TEM data, since prior to this study it had only been applied to synthetic data. Selective bandpass filtering, refraction and residual statics and f-x deconvolution procedures contributed to improved seismic images to the recorded two-way traveltime of 511.5 ms (approximately 1100 m depth). The TEM data were successfully inverted and converted to pseudo 2-D recovered resistivity sections that showed similar results to those from Frontier Geosciences. On the final seismic reflection sections, several strong reflectors are identified and the base of the overlying sedimentary layers is interpreted at a depth of ~600 m. The TEM results show consistent vertical structure with minimum horizontal variation across all lines to a valid depth of ~150 m. However, neither TEM nor seismic reflection results provide any information that correlates well with the observed TMI anomaly.
82

The Impact of a Metacognitive Reflection Component in a Problem-Based Learning Unit

Seifert, Kathryn A. 16 January 2010 (has links)
This mixed methods dissertation explores the impact of metacognitive support (reflective journal entries and a think-aloud exercise) in a PBL (problem-based learning) unit. While students are developing a solution for a PBL unit they may become occupied solely in solving the problem or task and not take time to fully consider what and how they have learned. This study examined how a metacognitive reflective component in a problem-based learning curriculum aids the learning process. The problem explored in this dissertation is that though problem-based learning may engage students, it is not known to what extent reflection adds to learners? development and application of critical thinking skills such as problem solving. The participant observer taught a problem-based learning unit concurrently with a poetry unit in three secondary senior-level English/language arts classrooms over a six weeks period. Four data sources were analyzed quantitatively: a pre-test and post-test on poetry terms, students? essay scores, and a survey. To determine differences between groups ANCOVA (Analysis of Covariance) was used to analyze the results of the poetry terms pre-test and post-test of the two experimental groups and the control group. MANCOVA (Multivariate Analysis of Covariance) was used to compare the results of the two experimental groups and the control group on the criteria of the essay. MANCOVA was also conducted to compare survey results between the experimental groups and the control group. The ANCOVA and MANCOVA tests used SPSS software. Additionally, qualitative analysis used a constant comparison method to analyze students? journal entries and a think-aloud exercise to provide insights concerning the research questions. The overall findings of this study fail to lend support for the intervention that was examined. The quantitative analysis results were not statistically significant between the two experimental groups and the control group. While the qualitative data sources provided some insights regarding how students learn, the data did not indicate that this type of metacognitive support greatly impacted student learning over the course of this study.
83

Point Source Reflection From a Non-Uniform Seabed

Chu, Chung-Ray 05 August 2003 (has links)
Acoustic point-source reflection from an unperturbed seabed with a continuously varying density and sound speed profile in a fluid-like sediment layer overlying an elastic basement is considered in this paper. This fundamental problem has illuminated many interesting phenomena about the effects of sediment stratification on acoustic wave interactions with the seabeds. The analysis employs the analytical solutions for the Helmholtz equation in the sediment layer, in which the density and the sound speed are, respectively, described by three kinds of geological models. The results have demonstrated that the effects of sediment stratifacation are confined in a region in range, where the reflection field is dominated by the reflected ray bundles containing ray components with the grazing angles which are neither too steep nor too shallow. The effects of many other factors, such as frequency, sediment thickness, basement elasticity, on the reflection fields are investigated, in particular, the interface wave component may become important in the region close to the seabed, if the sediment thickness is relatively thin in comparison with the acoustic wave length.
84

Residual migration velocity analysis in the plane wave domain theory and applications /

Jiao, Junru, January 2001 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.
85

Residual migration velocity analysis in the plane wave domain : theory and applications /

Jiao, Junru, January 2001 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 181-185). Available also in a digital version from Dissertation Abstracts.
86

Residual migration velocity analysis in the plane wave domain : theory and applications

Jiao, Junru, 1959- 21 March 2011 (has links)
Not available / text
87

Cenozoic Extensional Tectonics Revealed Through Seismic Reflection Imaging, SE Arizona

Wagner, Frank Henry January 2005 (has links)
The Basin and Range province of western North America is a broad region of irregular topographic expression characterized by various styles of Cenozoic extension. Recent reprocessing and interpretation of a regional suite of industry seismic reflection profiles in southern Arizona, in the southern Basin and Range province of southwestern North America, have illuminated subsurface features related to Cenozoic crustal extension and show a detailed view of extensional processes in the southern Basin and Range. Seismic stratigraphic investigations on these profiles suggest a two-phase model for the evolution of the Catalina-Rincon metamorphic core complex, with an initial stage of isostatic core complex emplacement during detachment faulting that resulted in little topographic expression. This was followed, after a significant tectonic hiatus, by late-stage exhumation and flexural uplift of the metamorphic core complex controlled by younger high-angle faulting. Along-strike, upper-plate deformation in response to core complex emplacement was accommodated by the Santa Rita fault, south of the Catalina-Rincon metamorphic core complex. Finite-element models predicts early mechanical failure of the upper-plate of the detachment system to the south of the Catalina core complex. These models suggest that the Santa Rita fault is the result of a perturbation in the regional stress field caused by the Catalina detachment and the associated brittle failure of the upper plate from the extreme crustal extension associated with core-complex emplacement. These profiles, coupled with geologic and well control, indicate that the southwest-dipping Catalina detachment, the northwest-dipping Santa Rita fault, the east dipping Altar Valley fault, and the highly dissected Sierrita Mountains are all aspects of the same extensional event in the middle-Tertiary. These features all appear to merge into a broad zone of middle-crustal deformation and likely represent heterogeneous upper-crustal deformation in response to middle-to-lower crustal homogeneous deformation.
88

Vaiko ugdymo oraganizavimo refleksija:pradedančio pedagogo ir studento praktikanto gebėjimai / Organisational Reflection on a Child‘s Training: A First-Years Teacher‘s and a Student Teachers Abilities

Dambrauskienė, Asta 23 June 2006 (has links)
Asta Dambrauskienė. Theme of the Master of Science work: Organisational Reflection on a Child‘s Training: A First-Years Teacher‘s and a Student Teachers Abilities: preschool education Pedagogical University master degree studies/ The research adviser of the work is-doc. Vitolda-Sofija, Glebuvienė. The Pedagogical University of Vilnius, The Departmen of Childhood Studies.-Vilnius, 2006.-136 p. SUMMARY In the minds of teachers reflection coud become the core helping critically to analyse, to realize and give sense for the proceses of thinking, its forms and presumptions as well as for the spiritual world structure and its features. The aim of this master work is to reveal the specific features of the child‘s organisational reflection for a first- year teacher ant student teacher. In order to realize the aim here such research tasks are given: revealing a first –year teacher‘s and a student teacher‘s reflection on a child‘s knowledge competence as well as the reflection on training organisational competence of a first-year teacher and a student teacher. The work gives a theoretical analysis of the concept of reflection and also reveals the complication of reflection, helping to perceive its necessity to organize training. Having analysed reflection in action, reflection on action and reflection for action one can perceive a child‘s all organisational training. Having in mind that reflection as well as competence is knowledge and abilities to use it, this work analyses a... [to full text]
89

Professors' post-class reflection : a case study

Cao, Li, 1957- January 2000 (has links)
The topic of teacher reflection has been gaining greater attention in the education literature. Nevertheless, teachers' reflective processes have not been well understood. This study attempted to describe characteristics and content of professors' post-class reflection. More specifically, it attempted to determine whether professors engage in the reflection process consciously and ways in which this process can be characterized. Eight professors, representing two levels of teaching experience, teaching a lecture or seminar undergraduate class in humanities or engineering, participated in this case study. Interviews, classroom observations, and instructional plans and materials comprised the data sources. Transcripts of the interviews were analyzed thematically, using QSR NUD*IST 4. Findings indicate that professors' post-class reflection became a routine: it happened at different points of time, mostly right after the class, and as a continuous process. Their reflection involved a mixture of having intuitive feelings about the class as well as thinking logically about how the class unfolded. They reflected intentionally and for two major purposes: to get ready for the next class and to improve teaching in general. They were either unable to characterize their way of reflecting on the class or were very clear that their reflection was more an intuitive process than a rational one. They reflected mostly on their teaching performance, on the content covered in class, on the students, and on instructional contexts. Based on the results, a conceptual framework is proposed that describes professors' post-class reflection as interrelated with rational and non-rational information processing. The study contributes to a better understanding of the complex process of teacher thinking and informs the design of faculty development interventions that aim at promoting reflective practice.
90

Processing and analysis of seismic reflection and transient electromagnetic data for kimberlite exploration in the Mackenzie Valley, NT

Moore, David Anton 05 1900 (has links)
The Lena West property near Lac des Bois, NT, held by Diamondex Resources Ltd., is an area of interest for exploration for kimberlitic features. In 2005, Frontier Geosciences Inc. was contracted to carry out seismic reflection and time-domain transient electromagnetic (TEM) surveys to investigate the possibility of kimberlite pipes being the cause of total magnetic intensity (TMI) anomalies previously identified on the property. One small part of the property, Area 1915, was surveyed with two perpendicular seismic reflection lines 1550 m and 1790 m long and three TEM lines consisting of six or seven individual soundings each with a 200 m transmitter loop. The results generated by Frontier Geosciences did not indicate any obvious vertical features that correlated with the TMI anomaly. The purpose of this study is to reprocess the seismic reflection data using different approaches than those of Frontier Geosciences and to invert the TEM data using a 1-D inversion code, EM1DTM recently developed by the UBC Geophysical Inversion Facility, to improve upon previous results and enhance the interpretation. A secondary objective is to test the robustness of EM1DTM when applied to observed TEM data, since prior to this study it had only been applied to synthetic data. Selective bandpass filtering, refraction and residual statics and f-x deconvolution procedures contributed to improved seismic images to the recorded two-way traveltime of 511.5 ms (approximately 1100 m depth). The TEM data were successfully inverted and converted to pseudo 2-D recovered resistivity sections that showed similar results to those from Frontier Geosciences. On the final seismic reflection sections, several strong reflectors are identified and the base of the overlying sedimentary layers is interpreted at a depth of ~600 m. The TEM results show consistent vertical structure with minimum horizontal variation across all lines to a valid depth of ~150 m. However, neither TEM nor seismic reflection results provide any information that correlates well with the observed TMI anomaly.

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