Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Rocks.
Дисертації з теми "Rocks"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "Rocks".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Karpathakis, George. "Rock stories: The discourse of rocks and rock-collecting." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2008. https://ro.ecu.edu.au/theses/218.
Повний текст джерелаАнотація:
Humanity's relationship with rocks is a long-standing one. Belk (1995, p.2) describes archaeological evidence of early assemblages of rocks found in Cro-Magnon caves that would not be out of place in contemporary rock-collections. Historically, apart from being used as material for tools and buildings. rocks were also used for magical, pharmaceutical and decorative purposes. During the Renaissance and Enlightenment, the practice of collecting rocks became associated with the sense of discovery and the colonial expansion of western European civilization across world, and with advances in mining, science and industry. It is a practice that continues through to the present day. This thesis is an ethnography that asks contemporary rock collectors: why do they collect rocks? How do they collect rocks? And, how do they talk about them? Adapting Foucault's theoretical framework on discourse (1970) and utilising positions on collecting put forward by Baudrillard ( 1994), Belk ( 1995), Benjamin (1999), and others, the thesis analyses interviews and images of rock-collectors and their collections and puts forward a snapshot of the discourse of rocks and rock-collecting as currently practiced. The thesis's theoretical framework is first tested on texts of popular culture on rocks and rock-collecting to locate and identify the statements and discursive formations that make up the discourse, and then it is applied to the interviews of contemporary collectors talking about their collections. While some rock collectors practice alone and their approaches may appear idiosyncratic, others, sharing knowledge and experience, practice in a club environment. The collectors' approaches to rock collecting range from the taxonomic and scientific to the aesthetic and utilitarian, personal and historical, and, for some, to the metaphysical. In Australia some aspects of rock-collecting are allied to prospecting and mining. For some collectors the rocks are souvenirs, and are connected to travel. For other collectors rock-collecting is associated with understandings of nature, time and space. The interviews reveal that in a consumer society rocks are also commodities, with many of the collectors not only acquiring their rocks in the field, but also buying what they cannot find, or trade, for their collection. The analysis of the collectors' interviews demonstrates that the discourse does not stand as an isolated figure, but shares statements and configurations of statements with many other discourses in the field of knowledge, including science, history, archaeology and metaphysics. The interviews also illustrate how discourse and their associated practices are subject to external and internal rules and regulations, imposed by the State, and by institutions of academia and cultural and scientific practices, such as museums and universities. Some collectors aspire to emulate museums, and wish to share with others knowledge about to their collection through exhibition. The variety of themes and practices found in the interviews reinforce Foucault's proposition that within a discourse statements and configurations of statements may arise that are incompatible and form diffractions in the discourse. While apparently incompatible themes, variations and differences exist within the discourse, the analysis of the interviews and the conclusion of the thesis underscore the underlying unities of the discourse of rocks and rock-collecting.
2
Meyers, Anthony G. "The determination of rock mass strength for engineering design /." Title page, contents and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phm6134.pdf.
Повний текст джерела
3
Cheng, Pei-fen Caral. "Project report on direct shear tests for rock joints." Click to view the E-thesis via HKUTO, 2002. http://sunzi.lib.hku.hk/hkuto/record/B42576659.
Повний текст джерела
4
Lock, Yick-bun. "An examination of failure criteria for some common rocks in Hong Kong /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17665164.
Повний текст джерела
5
Liu, Hao. "Acoustic emission and crack development in rocks." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22786338.
Повний текст джерела
6
Wong, Chi-ho Howard. "Parametric study for a cavern in jointed rock using a distinct element model /." View the Table of Contents & Abstract, 2006. http://sunzi.lib.hku.hk/hkuto/record/B36616746.
Повний текст джерела
7
Wong, Wing-yee. "Permeability studies in rock fractures." View the Table of Contents & Abstract, 2002. http://sunzi.lib.hku.hk/hkuto/record/B30109334.
Повний текст джерела
8
Lin, Qiaoxing. "Strength degradation and damage micromechanism of granite under long-term loading." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B37115406.
Повний текст джерела
9
Cheng, Pei-fen Caral, and 鄭佩芬. "Project report on direct shear tests for rock joints." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B42576659.
Повний текст джерела
10
Liu, Hao, and 劉浩. "Acoustic emission and crack development in rocks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31242066.
Повний текст джерела
11
Bradley, Frankie M. "Picking up rocks." Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2008m/bradley.pdf.
Повний текст джерела
12
Akram, Muhammad. "The effect of zero point charge environment on rock fracture behavior." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-08142009-040230/.
Повний текст джерела
13
Priyono, Joko. "The effects of high energy milling on the performance of silicate rock fertilizers." University of Western Australia. School of Earth and Geographical Sciences, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0050.
Повний текст джерелаАнотація:
[Truncated abstract] Many researchers have proposed the use of silicate rock fertilizers (SRFs) as alternatives to chemical fertilizers. However, the application of SRFs in modern agricultural practices is limited due mainly to the slow release of plant-nutrient elements from SRFs and consequently many tonnes/ha of SRFs may need to be applied. Simple and inexpensive methods of modifying the physicochemical properties of SRFs are needed to improve the agronomic effectiveness of SRFs. This thesis is focused on the evaluation of high-energy milling to produce superfine particles to improve the effectiveness of mafic (basalt and dolerite) and felsic (gneiss and K-feldspar) rocks for use as fertilizers. The ground mafic rocks are for use as Ca and Mg fertilizers and the ground felsic rocks as K fertilizers. Laboratory and glasshouse experiments were conducted with several potential SRFs. In laboratory experiments, initially milled rocks (Ø< 250 μm for basalt, dolerite, and gneiss; Ø < 150 μm for K-feldspar) were further milled with a ball mill (Spex-8000) for 10, 30, 60, 90, and 120 min under dry and wet (rock/water ratio = 1/3) conditions. To investigate possible reaction between constituents, other subsamples of initially milled basalt, dolerite, and gneiss were added to reagent grade NaCl or KCl (4.5 g rock + 0.5 g NaCl or KCl) and milled for 120 min under dry and wet conditions. Basalt and dolerite were also mixed with K-feldspar at a ratio of 1 : 1 and milled for 120 min under dry and wet conditions. For use in the glasshouse experiment, the initially milled rocks were further milled with a vertical stirred ball mill for 1 h in a dry condition. The elemental and mineralogical compositions of the SRFs were determined using XRF and XRD. Effects of milling on major physicochemical properties of milled rocks were determined, including particle size (Malvern Mastersizer), surface area (BET-N2), quantities of amorphous constituents (XRD, oxalic acid-oxalate extraction, TEM), extractable cations (1M CH3COONH4 pH 7), pHH2O, and electric conductivity. Dissolution kinetics in 0.01M acetic-citric acids (for 56 days) and soil (for 10 months) were determined. Based on the results of these laboratory experiments, a glasshouse experiment was carried out for 12 months to evaluate the effects of SRF application on growth and nutrient uptake of ryegrass grown on several soils. Milling reduced particle size, enhanced amorphism, and increased the release of structural cations from the rocks, with the effects due to dry milling being greater than for wet milling. The optimum milling times which produced maximum amounts of exchangeable cations (Na, K, Ca, and Mg) were 30 - 90 min, depending on rock type. The use of NaCl and KCl as milling additives did not enhance the properties of the SRF
14
Holyoke, Caleb W. "Strain weakening in crustal and upper mantle lithologies : processes and consequences /." View online version; access limited to Brown University users, 2005. http://wwwlib.umi.com/dissertations/fullcit/3174620.
Повний текст джерела
15
Lin, Qiaoxing, and 林僑興. "Strength degradation and damage micromechanism of granite under long-term loading." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B37115406.
Повний текст джерела
16
Wong, Chi-ho Howard, and 黃志豪. "Parametric study for a cavern in jointed rock using a distinct elementmodel." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B45014383.
Повний текст джерела
17
Stoffle, Richard W., Lawrence L. Loendorf, Diane E. Austin, David B. Halmo, Angelita S. Bulletts, and Brian K. Fulfrost. "Tumpituxwinap (Storied Rocks): Southern Paiute Rock Art in the Colorado River Corridor." Bureau of Applied Research in Anthropology, University of Arizona, 1995. http://hdl.handle.net/10150/279732.
Повний текст джерелаАнотація:
The Bureau of Reclamation (BOR) is interested in understanding the human and environmental consequences of past Glen Canyon Dam water release policies and using these data to inform future water release and land management policies. One step in this direction is to understand how American Indian people have used the Colorado River and adjoining lands in Glen Canyon and Grand Canyon. The BOR, through its Glen Canyon Environmental Studies (GCES) office, has provided funds for various American Indian groups to identify places and things of cultural significance in the 300 mile long river and canyon ecosystem that has come to be called the Colorado River Corridor. This study is the second to report on the cultural resources of the Southern Paiute people found in this riverine ecosystem.
The rock art study funded by the BOR and managed by the Glen Canyon Environmental Studies (GCES) office is the basis of this report. This study is unique in the history of rock art studies and is unusual when compared with other American Indian cultural resource assessments.
There are five unique features of this study. First, all funds for conducting the research were contracted to the Southern Paiute Consortium. Second, the Southern Paiute people decided during the previous studies that their next study would be about rock art. Third, the GCES /BOR permitted research to be conducted in terms of Paiute perceptions of the study area rather than specifically in terms of the scientifically established study area for the project. Thus, it was possible to conduct the Kanab Creek side canyon study. Fourth, all interviews were guided by a ten -page survey instrument, so Southern Paiute responses could be systematically compared. Fifth, both all-male and all- female research trips were conducted, thus producing the first gender - specific interviews of rock art sites. The resulting study is both interdisciplinary and multivocal.
18
Saigal, Girish C. "Petrological studies of Devonian rocks in Scotland and Cretaceous rocks in Canada." Thesis, University of St Andrews, 1985. http://hdl.handle.net/10023/15571.
Повний текст джерелаАнотація:
Sedimentological, petrological and geochemical studies have been carried out to analyse the process of calcretization and to understand the influence of environment of deposition on sandstone diagenesis. The sediments examined come from Lower Old Red Sandstones (Lr. Devonian) of eastern Scotland and hydrocarbon bearing Viking, Cardium and Belly River Formations (Cretaceous) of southcentral Canada. Some scepticism has been expressed regarding the occurrence of displacive calcite but this type of growth has been found in the calcrete profiles in Lower Old Red Sandstones of Carnoustie, east Scotland. This thesis presents fresh petrographic evidence of expansion and isolation of clastic grains by growing calcite crystals. The morphology of calcite crystals observed under cathodoluminescence provide compelling evidence that they are not a passive pore filling cement but have grown in confined spaces from supersaturated solutions by displacing the constraining medium. Field relationships suggest that the calcite was generated within the vadose zone where crystallization was promoted by rapid surface evaporation leading to supersaturation. A two-water model based on petrological and geochemical criteria has been suggested to explain the mechanism of growth of displacive calcite crystals (Chapter - IV). The recognition of displacive calcite is highly significant as it offers insight into paleoclimatic conditions and diagenetic history. Crystal morphologies observed under cathodoluminescence and microprobe data suggests that the displacive calcite was originally low Mg-calcite and grew from rapidly evaporating fresh pore waters with extremely low Mg/Ca ratios. The growth of originally low Mg-calcite and absence of palygorskite, sepiolite and dolomite in the Carnoustie calcretes is considered significant and it has been emphasized that no one process applies to all calcretes and the chemistry of pore waters and micro-environmental conditions within the pores are major significant factors controlling process of calcretization. The comparisons drawn between the diagenetic products observed in the Lower Old Red Sandstone and the Viking, Cardium and Belly River Formations suggest that the detrital mineralogy and aqueous solutions migrating through the pore system of sandstones are the two major factors that accomplish all the complex chemical reactions during diagenesis. In general, the Viking, Cardium and Belly River sediments show large variations in their pre-burial early diagenetic histories within small areas (even between adjoining wells) while the Lr. Old Red Sandstone show a monotonous paragenetic sequence over the entire area. This is compatible with the expected variations in the pore-fluid chemistry and micro-environmental conditions within the pores deduced from the depositional environments of these sediments. Hence it has been concluded that the pre-burial early diagenetic processes and products in clastic sediments are controlled by their environment of deposition which subsequently could influence the course of late stage diagenesis as well.
19
DeForest, David Scott. "Assessing"lithic sound" to predict a rock's ease of flaking." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4614.
Повний текст джерелаАнотація:
Thesis (M.A.) University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 22, 2007) Includes bibliographical references.
20
Huang, Wentao, Peter C. Lippert, Yang Zhang, Michael J. Jackson, Mark J. Dekkers, Juan Li, Xiumian Hu, Bo Zhang, Zhaojie Guo, and Hinsbergen Douwe J. J. van. "Remagnetization of carbonate rocks in southern Tibet: Perspectives from rock magnetic and petrographic investigations." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/624349.
Повний текст джерелаАнотація:
The latitudinal motion of the Tibetan Himalayathe northernmost continental unit of the Indian plateis a key component in testing paleogeographic reconstructions of the Indian plate before the India-Asia collision. Paleomagnetic studies of sedimentary rocks (mostly carbonate rocks) from the Tibetan Himalaya are complicated by potentially pervasive yet cryptic remagnetization. Although traditional paleomagnetic field tests reveal some of this remagnetization, secondary remanence acquired prior to folding or tilting easily escapes detection. Here we describe comprehensive rock magnetic and petrographic investigations of Jurassic to Paleocene carbonate and volcaniclastic rocks from Tibetan Himalayan strata (Tingri and Gamba areas). These units have been the focus of several key paleomagnetic studies for Greater Indian paleogeography. Our results reveal that while the dominant magnetic carrier in both carbonate and volcaniclastic rocks is magnetite, their magnetic and petrographic characteristics are distinctly different. Carbonate rocks have wasp-waisted hysteresis loops, suppressed Verwey transitions, extremely fine grain sizes (superparamagnetic), and strong frequency-dependent magnetic susceptibility. Volcaniclastic rocks exhibit pot-bellied hysteresis loops and distinct Verwey transitions. Electron microscopy reveals that magnetite grains in carbonate rocks are pseudomorphs of early diagenetic pyrite, whereas detrital magnetite is abundant and pyrite is rarely oxidized in the volcaniclastic rocks. We suggest that the volcaniclastic rocks retain a primary remanence, but oxidation of early diagenetic iron sulfide to fine-grained magnetite has likely caused widespread chemical remagnetization of the carbonate units. We recommend that thorough rock magnetic and petrographic investigations are prerequisites for paleomagnetic studies throughout southern Tibet and everywhere in general.
21
Chiu, Chi-kan, and 趙志勤. "Index properties and a three dimensional failure criterion of rocks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31222390.
Повний текст джерела
22
Li, Xiang. "Lifetime prediction for rocks." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2013. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-126371.
Повний текст джерелаАнотація:
A lifetime prediction scheme is proposed based on the assumption that the lifetime (time to failure) of rocks under load is governed by the growth of microstructual defects (microcracks). The numerical approach is based on linear elastic fracture mechanics. The numerical calculation scheme is implemented as a cellular automat, where each cell contains a microcrack with length and orientation following certain distributions. The propagation of the microcrack is controlled by the Charles equation, based on subcritical crack growth. The zone inside the numerical model fails if the microcrack has reached the zone dimension or the stress intensity factor of the crack reached the fracture toughness. Macroscopic fractures are formed by these coalesced propagating microcracks, and finally lead to failure of the model. In the numerical approaches, elasto-plastic stress redistributions take place during the forming of the macroscopic fractures. Distinct microcrack propagation types have been programmed and applied to the proposed numerical models. These numerical models are studied under different loading conditions. Numerical results with excellent agreement with the analytical solutions are obtained with respective to predicted lifetime, important parameters for the microcracks, fracture pattern and damage evolution. Potential applications of the proposed numerical model schemes are investigated in some preliminary studies and simulation results are discussed. Finally, conclusions are drawn and possible improvements to the numerical approaches and extensions of the research work are given本文认为微结构缺陷（微裂纹）的扩展决定了受力岩石的寿命（破坏时间）。基于此假设，提出了岩石寿命预测方法。利用线弹性断裂力学理论，通过FLAC进行了数值模拟。数值模型中每个单元定义一条初始裂纹，其长度与方向服从特定分布。基于亚临界裂纹扩展理论，由Charles方程决定微裂纹的扩展（速度）。如微裂纹发展至单元边界，或应力强度系数到达断裂韧度，则单元破坏。宏观裂纹由微裂纹所联合形成，并最终贯穿模型导致破坏。在形成宏观裂纹的过程中，发生弹塑性应力重分布。在数值模型中，编制了不同类型的微裂纹扩展方式，并在不同的受力条件下加以分析。数值模型的岩石寿命，裂纹形状，破坏方式以及一些重要的参数的数值模拟结果与解析解有较好的一致性。对本文所提出的数值模型的初步实际应用进行了分析，并讨论了计算结果。最后讨论了本文所提出的岩石寿命预测方法的可能改良与发展，并对进一步的研究工作给出建议。
23
Söderlund, Anders. "Procedural Modeling of Rocks." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-254208.
Повний текст джерелаАнотація:
Gaming and other virtual environments are a big part of today's society, but manual modeling of terrains used in such environments can be a lengthy and tedious process. This thesis serves to explore a few methods of procedurally generating models of rocks or boulders that could be used in such contexts. This includes geometry and shading. A couple of different methods are explored. Sphere inflation, inspired by a classic sphere modeling method, involves "inflating" a base mesh (usually a platonic solid) to grow towards the boundaries of a sphere using an iterative subdivision approach, halting at a predetermined level of iteration. The second approach, recursive subdivision of segmented edges, involves dividing a base mesh into edge segments based on a predefined segment size, subdividing a polygon with pre-segmented edges with a recursive subdivision method based on the sphere inflation subdivision scheme. The segmented edges method is followed by a corner cutting step to "carve" the base mesh into a shape approaching a rock. The segmented edge method was not successfully finished within due time, but the sphere inflation method shows promise in generating fairly believable rock models. The shading includes GLSL based fragment and vertex shaders employing a Perlin noise based procedural granite 3D texture.
24
Abdulrahman, Ahmed Abdulhamid. "The influence of water content on the rock cutting parameters of six rocks." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310034.
Повний текст джерела
25
Felton, David Scott. "Theoretical dissolution coefficient for rock fractures." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/21505.
Повний текст джерела
26
Guinea, Maysounave Ander. "Geoelectrical Characterization of Sulphate Rocks." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/77857.
Повний текст джерелаАнотація:
Gypsum rocks are widely exploited in the world as industrial minerals. The purity of the gypsum rocks (percentage in gypsum mineral –CaSO4•2H2O- in the whole rock) is a critical factor to evaluate the potential exploitability of a gypsum deposit. It is considered than purities higher than 80% in gypsum are required to be economically profitable. Gypsum deposits have been studied with geoelectrical methods; a direct relationship between the electrical resistivity values of the gypsum rocks and its lithological composition has been established, with the presence of lutites being the main controlling factor in the geoelectrical response of the deposit. This phenomenon has been quantified by means of a combination of theoretical calculations, laboratory measurements and field data acquisition. A geoelectrical classification of gypsum rocks defining three types of gypsum rocks has been elaborated.
Anhydrite (CaSO4) is frequently found in gypsum quarries and in no-outcropping sulphates. Because of its highest hardness than gypsum it supposes a problem for the extraction of gypsum; the fronts of the quarries in which anhydrite is found are stopped at the moment when it appears. The electrical properties of calcium sulphates have been studied by means of geoelectrical methods. The conductivity of crystals has been tested in laboratory.
A direct relationship between the electrical conductivity values of the calcium sulphate rocks and its lithological composition has been established being the lutitic matrix the main controlling factor when it is percolant (connected at long range). When the rock is matrix dominant, the electrical resistivity trend is bond to the Hashin-Shtrikman lower bound for multiphase systems. On the other hand, when the rock is calcium sulphate dominant the trend shows the one of the Hashin-Shtrikman upper bound. A geoelectrical classification for calcium sulphate rocks has been elaborated. With this classification it is possible to differentiate between calcium sulphate rocks with different composition according to their electrical resistivity value.
Glauberite (Na2Ca(SO4)2) is nowadays exploited as industrial mineral. Glauberite rocks usually have high lutite content in their composition, together with other evaporictic minerals as gypsum, anhydrite or halite among others. There is no reference to the conductivity of glauberite rocks in the bibliography, but due to their impurity it is expected to observe values as the observed for other sulphates in the matrix domain (less than 55% in purity). Two areas of the Ebro river basin (the Zaragoza and La Rioja sectors) have been studied by means of electrical resistivity tomography profiles, in which glauberite has been found in boreholes.
As example of application for the study of sulphate deposits, an electrical resistivity tomography survey has been carried out in the Pira Gypsum member (SE of Catalan margin of the Tertiary Ebro Basin, Spain). Additionally, a continuous coring drill was performed in order to support the study. Electrical imaging has been successfully applied to identify the gypsum deposits interlayered in lutite units. Another resistivity survey has been carried out in an active gypsum quarry in the Gelsa Gypsum unit (Zaragoza, N Spain). During the extraction of the rock, the most important parameters to know are the purity changes in the deposit. Sudden changes in the purity make the processing of the raw material less profitable. The performed profiles have shown different gypsum layers from which the purest layers have been identified.
Electrical resistivity tomography lines are useful in prospection of gypsum deposits. However, electrical imaging prospection should be supported by an accurate petrological study of the deposits, in order to properly interpret the resistivity profiles.Com a tècnica alternativa o complementària a la realització de sondejos, es proposen les tècniques geoelèctriques per a l'estudi de dipòsits de sulfats. En els estudis previs duts a terme que trobem en la bibliografia, les diferents roques sulfatades tenen assignats amplis rangs de resistivitat elèctrica i la seva classificació està pobrament desenvolupada. L'objectiu d'aquesta Tesi Doctoral és definir les propietats elèctriques de les roques sulfatades assignant-los rangs de valor de resistivitat elèctrica precisos i posant en relació la seva variació amb els canvis composicionals. A tal fi s'han dut a terme estudis a diferents escales. Addicionalment s'han dut a terme assajos de laboratori així com modelitzacions computacionals i càlculs teòrics amb els quals s'han comparat els resultats obtinguts en el camp. S'ha quantificat la relació entre la conductivitat elèctrica d'aquests materials amb la seva composició. Per a això, s'han dut a terme mesures en pastilles sintètiques amb diferents composicions i s'han elaborat models composicionals. S'han estudiat diferents formacions de sulfats amb composicions dispars mitjançant perfils de tomografia elèctrica. Gràcies a la comparació de resultats s'ha establert que la connectivitat entre les partícules de la matriu juga un paper clau. S'han analitzat les estructures que solen trobar-se en els dipòsits de sulfats mitjançant models teòrics i s'han comparat amb els perfils realitzats en el camp. Com a exemples d'aplicació, s'ha estudiat un dipòsit de guix en les rodalies de la localitat de Pira (Tarragona), on gràcies a la tomografia elèctrica ha estat possible diferenciar diferents nivells de guix i identificar el guix potencialment explotable amb finalitats industrials. En una pedrera a Gelsa (Saragossa) s'ha aplicat amb èxit la tècnica de la tomografia elèctrica per identificar nivells de guix de major puresa que estan sent actualment explotats en el front de pedrera i s'ha estudiat una zona en la qual la pedrera continuarà la seva explotació en el futur. En línies generals s'ha establert una base de dades sobre la conductivitat elèctrica de les roques de sulfats i s'ha demostrat la utilitat dels mètodes geoelèctrics en la seva exploració.
27
Dinh, Quoc Dan. "Brazilian test on anisotropic rocks." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2011. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-76331.
Повний текст джерелаАнотація:
The present work describes investigations on the anisotropic strength behavior of rocks in the splitting tensile test (Brazilian test). Three transversely isotropic rocks (gneiss, slate and sandstone) were studied in the Lab. A total of more than 550 indirect tensile strength tests were conducted, with emphasis was placed on the investigation of the influence of the spatial position of anisotropic weakness plane to the direction of the load on the fracture strength and fracture or fracture mode. In parallel, analytical solutions were evaluated for stress distribution and developed 3D numerical models to study the stress distribution and the fracture mode at the transversely isotropic disc. There were new findings on the fracture mode of crack propagation, the influence of the disc thickness, the influence of the applying loading angle and angle of the loading-foliation for transversely isotropic materialInhalt der Arbeit sind Untersuchungen zum anisotropen Festigkeitsverhalten von Gesteinen beim Spaltzugversuch (Brazilian Test). Laborativ wurden drei transversalisotrope Gesteine (Granit, Schiefer und Sandstein) untersucht. Insgesamt wurden mehr als 550 Spaltzugversuche durchgeführt, wobei der Schwerpunkt auf die Untersuchung des Einflusses der räumlichen Lage der Anisotropieebene zur Richtung des Lasteintrages auf die Bruchfestigkeit und das Bruchbild bzw. den Bruchmodus gelegt wurde. Parallel dazu wurden analytische Lösungen zur Spannungsverteilung ausgewertet sowie numerische 3D-Modelle entwickelt, um die Spannungsverteilung sowie den Bruchmodus bei einer transversalisotropen Scheibe zu untersuchen. Es wurden neue Erkenntnisse zum Bruchmodus, der Rissausbreitung, des Einflusses der Scheibendicke, dem Einfluss des Lasteinleitungswinkel sowie des Winkels Lasteintrag - Anisotropieebene für transversalisotropes Material gewonnen
28
Simpson, Annika Emilia. "Microbial weathering of volcanic rocks." Thesis, Open University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607463.
Повний текст джерелаАнотація:
The aim of this thesis was to further the knowledge on microbial weathering, by looking at the effect of model organisms (AcidithiobacilIus ferrooxidans and Geobacter metallireducens) to natural microbial communities (from basaltic glass). It was found that the medium water-rock ratio (50: I) provided the optimum conditions for A. ferrooxidans growth, whilst the low water-rock ratio (1: I) had a lower release of iron because of pH. The pH affected the release of iron and REEs, with less released the higher the pH. In addition, it was found that, though localised areas of hematite were found on the treated rocks, there were also oxidised layers that did not correspond to specific mineralogy. The lack of specific mineral signatures on the rock surface, but the apparent oxidation of the surface, suggested that the surface had been passivated with Fe3+ binding to the mineral surface. In contrast, G. metallireducens did not affect the production of Fe2+ from basalt glass when compared to controls. However, when low water-rock ratios and hematite were tested, a difference was observed between abiotic and biotic flasks. It was suggested the low water ~rock ratio possibly allowed G. metallireducens to obtain the iron more easily by affecting the pH of the solution which in turn affected the stability of the bound iron. In terms of studying microbial communities on rocks, it was found that community structure in Icelandic basaltic glass changed over time, becoming more diverse, with a switch from r- to K-selected microorganisms over the course of the year, similarly to results obtained in the field. DGGE results showed each flask had a distinctive population - with no correlation between ratios, and replicates different in composition to each other. It is suggested that, though community does change over time (as shown by the clone libraries), the ratios do not have an effect and each flask is developing with its own 'microbial island'. However, the results of the chemistry of the flask solutions indicated that the biological experiments showed differences in pH and elemental release between ratios. Elemental release rates were faster in the biological experiments. 'the natural communities affected mineral dissolution, possibly through -- the release of organic acids, which would also account for the drop in pHs observed in the biological experiments. It was noted that there were differences in dissolution rates between the results reported in this thesis and previous literature. It is suggested that these are caused by the rock surface area as in previous studies the rocks have typically been crushed into powder and fine particles. This crushed powder would have provided fresh rock surface for the microorganisms and also greater surface area for reactions to take place, accounting for generally higher weathering rates in previous literature per unit weight of material.
29
Dodd, Matthew S. "Biosignatures in Precambrian sedimentary rocks." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10055383/.
Повний текст джерелаАнотація:
The overarching goal of this work was to trace the origins of organic matter as a possible biosignature for early life on Earth. This work documented the petrological, structural, isotopic, elemental and molecular properties of organic matter, in a suite of sediments ranging from the Eoarchean to the Phanerozoic. Particular attention was paid to iron formations which form a major part of the Precambrian sedimentological record. Optical and micro-Raman spectroscopy were used to document the petrological occurrences of organic matter and its associated diagenetic features. Focused ion beam and transmission electron microscopy were used to detail the nanoscale structures of the organic matter. Mass spectroscopic techniques were utilised to measure the isotopic, elemental and molecular properties of organic matter and its petrographically associated carbonate. The timing and possible mechanisms of organic matter formation were investigated and evaluated, against the observed attributes of the organic matter. This work has documented organic matter forming key mineral associations with apatite and carbonate, which point to the diagenetic recycling of biogenic carbon. The diagenetic cycling of organic matter is proposed, to fuel the formation of granules during organic matter, iron and sulphur cycling. This cycling is hypothesised to lead to heterogeneity in organic matter structure and preservation in sediments. Additionally, this work has demonstrated that fluid deposited graphite in metamorphosed sediments may represent redistributed, syngenetic organic matter, shedding light on the controversial origins of graphite biosignatures in Earths oldest rocks. Finally, a detailed study of microfossil structures and their associations with organic matter and biominerals in iron formations was conducted to provide evidence for the preservation of Proterozoic microfossils, and the earliest signs of life on Earth.
30
Martinez, Ariel R. (Ariel Ruy) 1972. "Fracture coalescence in natural rocks." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/79986.
Повний текст джерела
31
Pei, Jianyong 1975. "Strength of transversely isotropic rocks." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43910.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.Includes bibliographical references (p. 253-259).
This thesis proposes a new Anisotropic Matsuoka-Nakai (AMN) criterion to characterize the failure of transversely isotropic rocks under true triaxial stress states. One major obstacle in formulating an anisotropic criterion is that it usually involves six stress components, instead of three principal stresses. As such, anisotropic criteria usually lead to complicated mathematical expressions, and cannot be directly visualized in three-dimensional space. This problem is solved by introducing the Material Normal Stress System (MNSS), which is the space formed by the three normal stress components reflecting the material anisotropy. Within this system, the failure behavior of transversely isotropic rocks in conventional triaxial tests can be represented with geometrical features in the MNSS. These features are then incorporated into the failure surface of the original Matsuoka-Nakai criterion in the Material Normal Stress System, resulting in the Anisotropic Matsuoka-Nakai criterion. This criterion, combined with the Coulomb criterion, is validated against both conventional and true triaxial test data, that are collected from an extensive literature review. The combination of the AMN criterion and the Coulomb criterion satisfactorily characterizes the measured strength from an extensive program of true triaxial tests on a schist, which confirms the ability of the proposed criterion. Finally, this combination of criteria is applied to the borehole stability problem. The necessary mud pressure against borehole collapse and the onset of borehole failure are examined.
by Jianyong Pei.
Ph.D.
32
Freiman, Gabriel, Jean-Pierre Korb, Benjamin Nicot, and Patrice Ligneul. "Microscopic wettability of carbonate rocks." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-192328.
Повний текст джерелаАнотація:
Nuclear Magnetic Relaxation Dispersion (NMRD) is strongly sensitive to the microscopic wettability of oil and brine bearing carbonate rocks. Exploring a very large range of low frequency enables isolating the typical NMRD dispersion features, 1/T1Surf, associated to
the different processes of molecular surface dynamics. This allows a separation of the surface and bulk microdynamics of oil and water even for a biphasic saturation of petroleum rocks. Several surface dynamical parameters were determined and related to the concept of microscopic wettability of oil and water in porous media.
33
Carvalho, Christian Bassoli de. "Nondestructive evaluation of riprap rocks." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0005403.
Повний текст джерела
34
Brocks, Jochen J. "Molecular fossils in Archean rocks." Phd thesis, School of Geosciences, 2001. http://hdl.handle.net/2123/14300.
Повний текст джерела
35
Chan, Heung-ngai. "Igneous and metamorphic rocks from SW Cyprus and NW Syria evidence for Cretaceous microplate collision and subsequent tectonic events in the Eastern Mediterranean /." Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B30711940.
Повний текст джерела
36
Carswell, Dennis Anthony. "Petrology, whole rock and mineral chemistry, thermobarometry and interpretation of high pressure metamorphic rocks." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/27764.
Повний текст джерела
37
SCARSI, MARCO. "Faulting, fluid-rock interaction and hydrothermal mineralisation in ultramafic rocks (Voltri Massif, Ligurian Alps)." Doctoral thesis, Università degli studi di Genova, 2018. http://hdl.handle.net/11567/929962.
Повний текст джерелаАнотація:
This study deals with reverse faults within intensely carbonated metalherzolites,
with related gold mineralisations, from the Voltri Massif, and in
particular within the Lavagnina Lakes area, in the Gorzente Valley. This area is
located in northwest Italy among the municipalities of Casaleggio Boiro, Lerma,
Mornese, and Bosio (Alessandria, Italy; GPS coordinates WGS84, 44.600685° N,
8.784286° E).
The Voltri Massif is a metaophiolitic complex, which occurs within the Eastern
edges of the Ligurian Alps. It is made up of of metaophiolitic rocks associated with
metasediments and slices of subcontinental lithospheric mantle. These rocks
underwent a complex Alpine tectono-metamorphic evolution, with blueschist- to
eclogite- facies peak metamorphism with variable retrogressive overprints.
For this study the analysed structures are the upper crustal deformational
events (UDC), from late- to post-orogenic linked to the collisional events. These
deformational events are linked to different structural regimes, and developed
during the late-Alpine to early-Appenine events.
The Lavagnina Lakes area is mainly characterised by outcrops of serpentinites,
lherzolites, metabasites, metagabbros, lenses of metasediments, and listvenites (in
decreasing order of volumetric extension). From a structural point of view, this
area is characterised by brittle to brittle-ductile systems of shear zones, with
associated carbonates and chalcedony-quartz veins associated with local gold
mineralisations.
Hydrothermal, carbon-rich fluids permeated the rocks and sustained these
deformation stages producing widespread and intense carbonate-rich alteration
zones, exclusive meso- and microstructures within carbonates fault zones, called
fault pearls, chalcedony shear veins along fault surfaces, widespread quartzchalcedony
and carbonates veining, and leading to local gold mineralisation.
The geological survey allowed identifying four main structures (Chapter 5) that
I studied in detail. In particular I studied the Bisciarelle Creek thrust fault for the
occurrence of meso- and microstructures never reported in literature, called fault
pearls. Their compositional and textural characteristics, described in chapter 5.3.4,
make the fault core of the Bisciarelle fault a peculiar geological object.
2
The data shown in chapter 7 provide constraints on the chemical properties of
the fluid that generate the intense carbonation along the Bisciarelle fault. Through
the mass transfer profiles was possible to identify and quantify those elements
transferred from the fluid to the rock and vice versa.
The morphometric image analysis results (Described in chapter 5.3.5) show
that the fault pearls have circular shape irrespective to the direction of observation
(parallel and orthogonal to the slickenlines), with values that indicate a nearly
perfect circular shape. These values are in line with the roundness values, hence
the fault pearls in three-dimensions can be considered as nearly perfect spheres or
as very spherical textures.
Single-spot SEM-EDS (Chapter 8) analyses show that ferroan dolomite makes
the pearl bands (CaO: 29.13±2.33 wt%; MgO: 19.03±4.86 wt%; FeO: 1.77±0.87
wt%) and that minor compositional variations across large and thin bands exist,
and that silica makes most of the chalcedony veins (SiO2: 97.97±3.23 wt%).
Elemental imaging by LA-ICPTOFMS (Chapter 8) provides a detailed account of
the distribution of chemical elements within pearls, matrix, and chalcedony shear
veins. Mineral paragenesis and elemental imaging by LA-ICP-TOFMS confirm the
hypothesis of hydrothermal derivation of the fault rock. This is best evaluated by
comparing the concentration ranges of the key trace elements As, Sb, In, Ga, Ag, Zn,
and Cu of fault pearls levels and chalcedony with those of the same elements in the
average upper crust. Such comparison clearly shows that the peak concentrations
of these elements are 5 (Cu, Zn) to 50 (Sb, In) times higher than those of the upper
crust, demonstrating that the Bisciarelle fault fluid was capable to transport and
deposit a suite of ore elements.
These evidences are fundamental to discuss the possible origin of the fluids that
developed the carbonation and the fluid-rock interactions along the Bisciarelle
thrust fault and along the main fault of the Lavagnina Lakes area.
On the basis of all the constraints described, the fault pearl features are
compatible with a genesis from a process called “transient” boiling in microfluidics.
This process occurs within cavities when a liquid is instantaneously overheated
and a vapour phase nucleates and expands up to explosive boiling, and so
generates a myriad of vapour bubbles. Such process, which occurred during mixed
mode fracturing in the fault, implies that pearls might reflect the liquid-vapour
3
fractionation of chemical elements in a boiling hydrothermal fluid during seismic
failure.
The close association of fault pearls with seismic-related structures such as submicron
carbonates coating of slip surfaces, quartz microtexture related to silica gel
deposition, syn-kinematic filamentous phase, injection veins with similar
characteristics and overpressure with respect to seismic pseudotachylites along
slip zone supports the hypothesis that fault pearls developed during shear events
at seismic rates, and hence are considerable as paleo-seismic events indicators.
Moreover I discuss the tectonic evolution of the Lavagnina Lakes area linked to
the syn-kynematic fluid rock interaction, the origin of the fluids and the gold
mineralisations of the area. The occurrence of syn-tectonic fluid flow and
consequent fluid-rock interaction (e.g. carbonation) along the two systems of
Reverse Shear Zones (RSZ1-RSZ2), is testified by: metasomatic alteration (ALT-1,
ALT-2, and ALT-3), at least three main systems of veins (V1, V2, and V3), and
hydraulic and cockade breccias. The evidence that the carbonation took place
along these structures, in particular along the RSZs systems, and within their
damage zones, highlights how these structures acted as important fluid pathways
and played a major control in the distribution of the ore deposits.
Finally, I stress out further consideration about the comparison between the
gold mineralisations of the area with the gold mineralisations of the whole Voltri Massif.
38
Tang, Yin-tong. "Rock stress determination in Hong Kong Island by using hydraulic fracturing method /." View the Table of Contents & Abstract, 2005. http://sunzi.lib.hku.hk/hkuto/record/B36357625.
Повний текст джерела
39
Thorn, Brian T. "The hand that rocks the cradle rocks the world, women in Vancouver's Communist movement, 1935-1945." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ61609.pdf.
Повний текст джерела
40
Neal, J. David. "Life on the rocks, environmental perceptions of the Rock Crawlers, a Western American recreational commmunity." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0017/NQ47499.pdf.
Повний текст джерела
41
Zedeno, M. Nieves, Richard W. Stoffle, Genevieve Dewey-Hefley, and David Shaul. "Storied Rocks: American Indian Inventory and Interpretation of Rock Art on the Nevada Test Site." Bureau of Applied Research in Anthropology, The University of Arizona in Tucson, 1999. http://hdl.handle.net/10150/272093.
Повний текст джерелаАнотація:
This government-to-government consultation between the Department of Energy, Nevada Operations Office (DOE /NV) and the Consolidated Group of Tribes and Organizations (CGTO) focused on the interpretation of 10 rock art sites; seven on the Nevada Test Site (NTS), and three on the Yucca Mountain Site Characterization Office (YMSCO).
The consultation entailed a systematic ethnographic study of petroglyphs, pictographs, and other rock art manipulations. The objective of the project was to gain an understanding of the cultural significance of rock art for contemporary American Indians and its place in their traditional cultural landscapes. Research activities involved visits to rock art sites by tribal elders and tribal cultural experts. During the field visits, Indian consultants responded to standardized interviews and provided observations, comments, and recommendations regarding each of the sites under study.
The project involved 14 American Indian tribes and two Indian organizations that represent Indian people having aboriginal and historic ties to lands currently occupied by the NTS. The study was initiated as part of the overall DOE /NV American Indian Program, which includes a decade of project - specific and general consultation efforts. This study built upon previous efforts and contributed to DOE /NV's understanding of American Indian cultural resources on the NTS.
42
Sidborn, Magnus. "Modelling Some Biochemically Processes in Rocks." Licentiate thesis, KTH, Chemical Engineering and Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1679.
Повний текст джерелаАнотація:
A model for studying oxygen depletion in subsurfacefractured rock have been developed. It is based on currentknowledge in several different reasearch disciplines such asgeology, microbiology and hydrology. The model may be a usefultool for predicting oxygen penetration in rock fractures. Thisis important for example in the safety assessment of a deeprock nuclear waste repository. In such a repositroy a reducingenvironment is desirable. Several potential oxygen consumingprocesses, both parallel and serial, were identified, each ofwhich may considerably contribute to the depletion of oxygen.Abiotic as well as microbially mediated oxidation of rockminerals coupled with transport processes, both in thefractures and the rock matrix, were included. The model wasdivided into a number of case studies in which only one or afew processes were studied at a time. The different cases werethen compared so that the relative importance of each processcould be evaluated at different conditions. Even if it would bepossible to model all the processes simultaneously, thisapproach was chosen from result transparency and numericalefficiency reasons. The results show that in a relatively shorttime perspective, when oxidizable minerals are available in thefracture, reaction kinetics are important. In a long timeperspective, however, minerals in and adjacent to the fracturebecome oxidized and matrix diffusion is rate limiting.
43
Maybee, William Gregory. "Pillar design in hard brittle rocks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0011/MQ61284.pdf.
Повний текст джерела
44
Prasad, Umesh. "Dynamic fracture characteristics of selected rocks." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36826.
Повний текст джерелаАнотація:
Fragmentation by blasting is distinct from other method of rock breakage due mainly to the short time scale involved in the application of stresses. In the present work, the dynamic rock properties, applicable to non-static fragmentation process have been measured and compared with measured values of other fracture related properties. Further, these are examined to establish correlation with respect to their physical, mineralogical and micro-structural characteristics. The rock types selected for the present work ranged from nearly homogenous isotropic rock to an-isotropic rocks. The nearly isotropic rock were represented by three different types of granites. The an-isotropic rocks consisted of gneissic granite, gneiss, marbles, limestone, and quartz.The dynamic compressive strength, measured under a strain rate of 10 3/sec, has been found to be about 2.5--4.6 times the compressive strength measured under static conditions (strain rate of 10-6 /sec) for similar dimensions of rock samples in a wide variety of rock types. It has also been found that this ratio is higher for low strength rocks, and lower for high strength rocks.
The particle size distribution resulting from high velocity impact breakage is much smaller than in the static case. The degree of fineness (50% passing) generated under dynamic breakage is well correlated with the dynamic compressive strength; however, there appears to be no correlation between static compressive strength and the corresponding fragment size distribution.
Except for static compressive strength, the dynamic strength was found to have no significant correlation with the measured values of fracture toughness, tensile strength, or comminution work index.
The fracture toughness value is found to be controlled by the largest crack or grain size and to some extent, by porosity. The effect of crack density appeared to be non-linear; the fracture toughness initially decreases with increase in crack density, but further increase in the latter results an increase in toughness. This suggests the behaviour of rocks in dynamic compressive breakage is different than that due to static single crack growth.
The work index (WI), which represents a fracture process at an intermediate strain rate correlates better with the Brazilian tensile strength than the static and high strain rate compressive strengths. (Abstract shortened by UMI.)
45
Blake, Oshaine Omar. "Seismic transport properties of fractured rocks." Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.569902.
Повний текст джерелаАнотація:
Fracture in rock is a major factor that affects the rock's physical properties and it also provides the route for the passage of fluids that can transport potentially hazardous substances and hydrothermal fluids. Assessment of the degree of fracture in rocks is important as they play an essential role in many geomechanical issues (stability of boreholes, stimulation of oil and geothermal reservoirs, the design of civil structures, tunnels and hazardous waste disposals), and in understanding a number of processes in the Earth's crust such as magmatic intrusions, plate tectonics, fault mechanics and sedimentary basins. The fundamental understanding of how seismic waves are altered when they pass through fractured rock are currently poorly understood, hence a comprehensive study is timely. An improved understanding of how fractures affect the physical properties (such as seismic velocity and attenuation) would significantly enhance our ability to predict the fracture state of rock at depth remotely. The main focus of this thesis is to characterize P and S wave velocity, their ratio, shear wave splitting and attenuation and their dependence on the fracture density of the rock. Laboratory experiments were carried out in uniaxial compressive condition to increase microfracture density and hydrostatic confining condition to close microfractures. Experiments were performed on a single rock type (Westerly granite) to keep the mineralogy, chemical composition, and grain size constant. The condition of the microfractures was dry to remove the complexity of saturation and fluid type. Through transmission technique was used to measure P and S wave velocities and spectral ratio technique was used to measure attenuation. P and S wave velocities were measured at 1.5MHz. Attenuation measurements were made in the frequency range of O.8MHz to 1.7MHz. Elastic properties can be measured statically where strain data are recorded and related to stress during slow loading of a specimen, or dynamically, where the elasticity can be calculated from the velocity of P and S waves. In order to understand the elastic properties of the crust at depth using seismology, the relationship between the static and dynamic properties must be known. Increasing-amplitude, uniaxial cyclic loading experiments were carried out to investigate and quantify the effect of microcracking on the elastic properties, and to establish a relationship between static and dynamic measurements. There is a linear relationship between static and dynamic Young's moduli, and a significant discrepancy between the static and dynamic Poisson's ratio. We attribute the differences in the static and dynamic elastic properties to the size distribution of the crack population relative to the amplitude and frequency of the applied stress, frictional sliding on closed cracks during loading/unloading, and the assumption of isotropic elasticity in the sample. Strong stress-dependency exists in the uniaxial compressive and hydrostatic confining conditions due to closure of microcracks. This resulted in: an increase in the P and S wave velocities, their ratio, static and dynamic Young's modulus, and static and dynamic Poisson's ratio; and a decrease in the P and S wave attenuation. The increase of fracture density caused: a decrease in the P and S wave velocities and static and dynamic Young's modulus; a small increase in the dynamic Poisson's ratio and VpNs; and a large increase in the static Poisson's ratio, and P and S wave attenuation. Seismic wave attenuation is more sensitive than seismic wave velocity to closure of microcracks and Increase of microfracture density. The effect of varying crack density on the P and S wave velocities and elastic properties under confining pressure (depth) were quantified. The elastic wave velocities and Young's modulus of samples that have a greater amount of microcrack damage required higher confining pressure to be equal to those of samples with no induced microcrack damage. We found that fractures are completely closed at ~5km (~130MPa) in crystalline rocks. At shallow depth (less than 5km), fracture density affects seismic wave velocities. We observed an overall 6% and 4% reduction in P and S wave velocities respectively due to an increase in the fracture density. The overall reduction in the P and S wave decreased to 2% and 1 % at ~2km. Consequently, assessing the degree of fracture between 2km and 5km using seismic wave velocities may be difficult
46
Bonet, Cruz Marisabel P. "Piedra entre olas = Rocks amidst waves." Honors in the Major Thesis, University of Central Florida, 2000. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/186.
Повний текст джерелаАнотація:
This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Arts and Sciences
English
47
Noorian-Bidgoli, Majid. "Strength and deformability of fractured rocks." Doctoral thesis, KTH, Mark- och vattenteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-155719.
Повний текст джерелаАнотація:
This thesis presents a systematic numerical modeling framework to simulate the stress-deformation and coupled stress-deformation-flow processes by performing uniaxial and biaxial compressive tests on fractured rock models with considering the effects of different loading conditions, different loading directions (anisotropy), and coupled hydro-mechanical processes for evaluating strength and deformability behavior of fractured rocks. By using code UDEC of discrete element method (DEM), a series of numerical experiments were conducted on discrete fracture network models (DFN) at an established representative elementary volume (REV), based on realistic geometrical and mechanical data of fracture systems from field mapping at Sellafield, UK. The results were used to estimate the equivalent Young’s modulus and Poisson’s ratio and to fit the Mohr-Coulomb and Hoek-Brown failure criteria, represented by equivalent material properties defining these two criteria. The results demonstrate that strength and deformation parameters of fractured rocks are dependent on confining pressures, loading directions, water pressure, and mechanical and hydraulic boundary conditions. Fractured rocks behave nonlinearly, represented by their elasto-plastic behavior with a strain hardening trend. Fluid flow analysis in fractured rocks under hydro-mechanical loading conditions show an important impact of water pressure on the strength and deformability parameters of fractured rocks, due to the effective stress phenomenon, but the values of stress and strength reduction may or may not equal to the magnitude of water pressure, due to the influence of fracture system complexity. Stochastic analysis indicates that the strength and deformation properties of fractured rocks have ranges of values instead of fixed values, hence such analyses should be considered especially in cases where there is significant scatter in the rock and fracture parameters. These scientific achievements can improve our understanding of fractured rocks’ hydro-mechanical behavior and are useful for the design of large-scale in-situ experiments with large volumes of fractured rocks, considering coupled stress-deformation-flow processes in engineering practice.QC 20141111
48
Kimber, Roger Neil. "Carboniferous basement rocks of northern Britain." Thesis, Durham University, 1987. http://etheses.dur.ac.uk/6787/.
Повний текст джерелаАнотація:
The study of Carboniferous basement rocks of northern Britain has concentrated on the dominantly clastic rock succession which unconformably overlies the Lower Palaeozoic basement and occurs beneath the lowermost Carboniferous limestones in areas surrounding the Vale of Eden. The clastic rocks exposed at Shap, the Mell Fells (Ullswater), Sedbergh and Cross Fell, mainly reflect fluvial deposition over an Upper Palaeozoic landscape which locally had considerable topographic relief. Within each clastic rock succession, which throughout the region varies in thickness from ca 4m to over 250m, overall largescale fining upward sequences document the evolution from gravel-dominated braided fluvial to sand-dominated braided fluvial deposits. This evolution is shown to be representative of the downstream transition from localised alluvial fans into a more extensive fluvial braidplain system, the latter also containing marked proximal to distal variations. Palaeocurrents are consistently toward the north and north-east throughout the region, demonstrating the existence of a broad northerly palaeoslope during clastic deposition. Proximal to distal relationships and clast provenance data for each area are used to predict fades variations across the Vale of Eden region and to reconstruct the Palaeogeography. Areas of high ground are shown to be underlain by deep-seated Caledonide granite plutons, evolution of the fluvial braidplain demonstrating that with time denudation of high ground developed fining upward sequences by the superposition of progressively finer grained sediment on coarse. The development of the braidplain system is related to post-intrusive uplift of the granites underlying the highest ground with deposition mainly taking place prior to marine limestones associated with the basal Carboniferous marine transgression. A comparison with the Upper Old Red Sandstone clastic succession of the Northumberland Border Basin is assessed.
49
Esfarjani, H. R. "Engineering properties of basic igneous rocks." Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374739.
Повний текст джерела
50
Perarnau, A. "Palaeomagnetic studies of some Venezuelan rocks." Thesis, University of Newcastle Upon Tyne, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.351725.
Повний текст джерела