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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.
101

A case study of the social and economic impact of structural adjustment on rural agricultural development in middle belt Nigeria

Oritsejafor, Emmanuel 01 July 1995 (has links)
The premise of this study is the assumption that the IMF policy of structural adjustment has led to the decline of the social and economic welfare of the rural sector in the Middle Belt region of Nigeria. With this basic research theme in mind: (i) colonial agricultural development policy in Nigeria before the period of independence was evaluated; (ii) various development plans that have been instrumental in the development of the agricultural sector since independence were analyzed; (iii) the economic management policy of both civilian and military governments in Nigeria were examined; (iv) how SAP led to the proliferation of multinational corporations in the Nigerian agribusiness and the impact it had on domestic manufacturers engaged in farming for other reasons than farming was shown; and (v) quantitative method was used in an attempt to measure the impact of SAP in Nigeria's Middle Belt region. However, various perceptions exist regarding the policy of structural adjustment. Some observers argue that the policy was necessary in order for developing countries to attain sustainable growth in their economies. Other observers saw structural adjustment as a policy that has further perpetuated the economic hardship in developing states. This paper's position is that certain aspects of structural adjustment have clearly led to the continuous economic hardship and neglect of the rural sector, as shown in this case study of Plateau State. In order to substantiate this thesis, qualitative and quantitative data was assessed regarding the impact of SAP in four communities in the Middle Belt of Nigeria. Primary and secondary data regarding the policy objectives of structural adjustment was reviewed. Findings revealed that clearly certain aspects of SAP had effects on the socio and economic welfare of the rural people in this case study. However, other factors such as the lack of representation at the level of national leadership and ethnicity have contributed to the neglect of the rural sector in the Middle Belt region of Nigeria. In conclusion the recommendation is made that the Nigerian leadership need to reprioritize their commitment to the agricultural sector and that rural farmers should be given adequate social and economic assistance.
102

OSSOS. V. Diffusion in the Orbit of a High-perihelion Distant Solar System Object

Bannister, Michele T., Shankman, Cory, Volk, Kathryn, Chen, Ying-Tung, Kaib, Nathan, Gladman, Brett J., Jakubik, Marian, Kavelaars, J. J., Fraser, Wesley C., Schwamb, Megan E., Petit, Jean-Marc, Wang, Shiang-Yu, Gwyn, Stephen D. J., Alexandersen, Mike, Pike, Rosemary E. 19 May 2017 (has links)
We report the discovery of the minor planet 2013 SY99 on an exceptionally distant, highly eccentric orbit. With a perihelion of 50.0. au, 2013 SY99' s orbit has a semimajor axis of 730 +/- 40. au, the largest known for a high-perihelion trans-Neptunian object (TNO), and well beyond those of (90377) Sedna and 2012 VP113. Yet, with an aphelion of 1420 +/- 90. au, 2013 SY99' s orbit is interior to the region influenced by Galactic tides. Such TNOs are not thought to be produced in the current known planetary architecture of the solar system, and they have informed the recent debate on the existence of a distant giant planet. Photometry from the Canada-France-Hawaii Telescope, Gemini North, and Subaru indicate 2013 SY99 is similar to 250. km in diameter and moderately red in color, similar to other dynamically excited TNOs. Our dynamical simulations show that Neptune's weak influence during 2013 SY99' s perihelia encounters drives diffusion in its semimajor axis of hundreds of astronomical units over 4. Gyr. The overall symmetry of random walks in the semimajor axis allows diffusion to populate 2013 SY99' s orbital parameter space from the 1000 to 2000. au inner fringe of the Oort cloud. Diffusion affects other known TNOs on orbits with perihelia of 45 to 49. au and semimajor axes beyond 250. au. This provides a formation mechanism that implies an extended population, gently cycling into and returning from the inner fringe of the Oort cloud.
103

Fluids in metapelitic granulites and Bulai granitoids of the Messina area, central zone of the Limpopo Belt, South Africa

28 January 2009 (has links)
M.Sc. / A fluid inclusion study was performed on the following rock types: ● Metapelitic granulites that occur as xenoliths in the Bulai Pluton. ● Metapelitic granulites that occur around the Bulai Pluton. ● Granite from the Bulai Pluton. These rocks outcrop on the farm Boston near Messina in the so called Three Sisters area. The main aims of this study are the following: ● Which fluids are associated with granulite metamorphism? ● Do the fluid inclusions record more than one metamorphic event, if so, what are the P-T conditions of this/these event(s)? ● How do the fluids compare to fluids in the Southern Marginal Zone in terms of composition and density? The metapelites are typically characterised by a peak metamorphic mineral assemblages of (1) quartz, K-feldspar, plagioclase, garnet, biotite, cordierite and sillimanite and (2) quartz, K-feldspar, plagioclase, garnet, orthopyroxene and biotite. The first assemblage have been used by other workers (Van Reenen et al., in prep.) to derive a P-T path for the metapelitic xenoliths and host rock, which is characterised by decompression-cooling. This assemblage also shows typical high temperature metasomatic formation of feldspar around quartz that is in contact with quartz. The peak metamorphic conditions were estimated to be ~850°C and ~7.5 kbar. Fluid inclusions were studied in garnet, quartz inclusions in garnet, and matrix quartz. The following principle fluid types were identified: ● High salinity aqueous fluids. ● CO2-rich (±CH4) carbonic fluids. ii Petrographic evidence indicates that both fluids were present at peak metamorphic conditions under conditions of fluid-fluid immiscibility. The high-salinity aqueous fluid is most likely responsible for the high temperature metasomatic textures. The density of the fluids trapped at peak metamorphic conditions have been reset to lower values at pressures below that of the peak metamorphic conditions. This is probably the result of the emplacement of the Bulai Pluton at shallow crustal levels (2- 3 kbar). Later fluids are dominated by low-density carbonic fluids with significant amounts of CH4. The CH4 is the result of retrograde hydration reactions at relatively low oxygen fugacities.
104

Primary uranium mineralisation of the central Damara Orogen, Namibia: a petrographic, geochemical and mineralogical account of the granite - hosted uranium deposits situated along the Swakop- and Khan River valleys / Primary uranium mineralisation of the central Damara Orogen, Namibia

Freemantle, Guy George January 2017 (has links)
A thesis submitted to the Faculty of Science in fulfilment of the requirements for the degree of Doctor of Philosophy at the School of Geosciences University of the Witwatersrand, Johannesburg, 2017 / Namibia, the 6th largest producer of uranium globally, has produced uranium from Pan African granite-hosted (primary) deposits since 1976, and from palaeochannel deposits since 2007; exporting 3 472 tonnes U in 2016. The large granite-hosted deposits at the Husab Mine are expected to add over 5 700 tonnes U/year at peak, while three large primary-hosted deposits remain in various stages of development at Goanikontes, the Ida Dome, and Valencia. This study presents a comprehensive geological, geochemical and uranium mineralogical appraisal of four of the major primary-hosted uranium deposits, all situated within the southern Central Zone (sCZ) of the polydeformational (D1-D3) Damara Belt. The sCZ comprises highly deformed Neoproterozoic sediments, unconformably draped over rheologically competent granite-gneiss domes and inliers of a Palaeoproterozoic basement. A suite of fractionated sheeted leucogranites (SLGs) are a characteristic of the final stages of Orogenic deformation; while most SLGs appear to precede D3 deformation and metamorphism (ca. 510 Ma); most of the mineralised SLGs across the region invade reduced-facies sediments in pressure shadows formed in the hinges and limbs of upright D3 antiforms, proximal to basement inliers. A pre-existing, six-fold, alphabetised SLG classification scheme is revised and extended to categorise distinctive and consistent field and petrographic characteristics of the SLGs across the region. Discriminating SLG sub-types is less consistent in standard geochemical diagrams, except where high field-strength (HFS) and rare-earth elements (REE) are concerned. REE profiles in pre-D3 SLGs reflect abundances, or paucities, of characteristic accessory mineral assemblages; while REE profiles show relative REE enrichment, prominent REEfractionation and -ve Eu anomalies in the uraniferous SLGs, reflecting lower-percentage partial melts in the more uraniferous samples. The overwhelming majority of primary uranium mineralisation is in magmatic uraninite, followed by coffinite which predominate as a replacement phase of uraninite, and more rarely as solid solution with thorite. The refractory minerals betafite and brannerite are rare, but are locally abundant in discrete, magmatic textures within uraniferous SLGs of some deposits. Hydrated uranyl silicates predominate in the supergene portions of the orebodies across the region. An electron microprobe study presents the first comprehensive assessment of uraninite compositions in the region, while Husab deposit betafite and brannerite compositions allow for a well-rounded comparison with refractory minerals from the Rössing deposits. Key Words Primary Uranium, Granite, Orogenic, Damara, Namibia, Rare Earth Elements, Mineralisation, Fractionation, High-grade Metamorphism, Economic Geology, Mining, Processing, Uraninite, Coffinite, Etango, Goanikontes, Husab, Ida Dome, Rössing, Valencia / XL2018
105

Geocronologia, geoquímica isotópica e litoquímica do plutonismo diorítico-granítico entre Lavras e Conselheiro Lafaiete: implicações para a evolução paleoproterozóica da parte central do Cinturão Mineiro / Geocronology, isotopic geochemistry and geochemical of the dioritic-granitic plutonism between Lavras and Conselheiro Lafaiete: implicatins to paleoproterozoic evolution of Mineiro Belt central part

Nunes, Luciana Cabral 19 October 2007 (has links)
A área de estudo localiza-se na borda sul do Cráton São Francisco, no Cinturão Mineiro, este é porção integrante da Província Sul Mineira. Neste contexto ocorre um mosaico de terrenos arqueanos e paleoproterozóicos de alto a médio grau metamórfico e associações granitogreenstone. Os corpos plutônicos, estudados neste trabalho, fazem parte do abundante plutonismo paleoproterozóico intrusivo nos greenstone belts Nazareno (Arqueano) e Rio das Mortes (Proterozóico). Dentro deste contexto ocorre a zona de Cisalhamento do Lenheiro (ZCL), que delimita estes greenstones belts: Nazareno (ao sul da falha) e Rio das Mortes (ao norte da falha); assim como plutons paleoproterozóicos. Os plutons escolhidos para este trabalho foram: Gnaisse Granítico Fé, Granito Mama Rosa, Tonalito/Trondhjemito Cassiterita, Granito Ritápolis, Diorito Brumado e Quartzo Monzodiorito Glória, localizados ao norte da ZCL; e: Granitóide do Lajedo, Granitóide Gentio, Quartzo Diorito Dores do Campo, Quartzo Diorito do Brito, Granodiorito Brumado de Baixo e Granodiorito Brumado de Cima, localizados ao sul da ZCL. Os estudos petrográficos indicam as seguintes características para os corpos: Gnaisse Granítico Fé (monzogranito a sienogranito), Granito Mama Rosa (monzogranito), Tonalito/Trondhjemito Cassiterita (tonalito a granodiorito), Granito Ritápolis (tonalito, granodiorito, monzogranito e sienogranito), Diorito Brumado (Diorito, quartzo diorito e tonalito), Quartzo Monzodiorito Glória (quartzo diorito, quartzo monzodiorito e tonalito), Granitóide do Lajedo (granodiorito), Granitóide Gentio (k-feldspato granito), Quartzo Diorito Dores do Campo (quartzo-diorito), Quartzo Diorito do Brito (quartzo-diorito), Granodiorito Brumado de Baixo (granodiorito a monzogranito) e Granodiorito Brumado de Cima (granodiorito a monzogranito). Os plutons Fé, Mama Rosa e Lajedo possuem composição peraluminosa/metaluminosa, o Quartzo Diorito Dores do Campo é metaluminoso e o Granitóide Gentio é peraluminoso. O Gnaisse Granítico Fé, Granito Mama Rosa e Granitóide Gentio variam desde o campo cálcioalcalino até shoshonítico em decorrência dos conteúdos de K2O, já o Granitóide do Lajedo é cálcio-alcalino e o Quartzo Diorito Dores do Campo varia de toleítico e cálcio-alcalino. Foram obtidas idades de cristalização U/Pb (TIMS) em zircão do: Gnaisse Granítico Fé (2191 ± 9 Ma), Granitóide do Lajedo (2208 ± 26 Ma), Granitóide Gentio (2066± 10 Ma - idade mínima) e Quartzo Diorito Dores do Campo (2198 ± 6 Ma). Os resultados dos isótopos de Nd/Sr dos corpos são: Gnaisse Granítico Fé (eNd(2190Ma) = - 3,1; TDM = 2,7 Ga; 87Sr/85Sri = 0,70497); Granito Mama Rosa (eNd(2121Ma) = - 5,3; TDM = 3,0 Ga; 87Sr/85Sri = 0,70497), Tonalito/Trondhjemito Cassiterita (eNd(2162Ma) = - 0,1; TDM = 2,5 Ga; 87Sr/85Sri = 0,73427), Granito Ritápolis (eNd(2121Ma) = - 2,4; TDM = 2,5 Ga; 87Sr/85Sri = 0,73427), Diorito Brumado (eNd(2131Ma) = - 2,6; TDM = 2,71 Ga; 87Sr/85Sri = 0,71362), Quartzo Monzodiorito Glória (eNd(2189Ma) = - 3,4; TDM = 2,7 Ga; 87Sr/85Sri = 0,70510), Granitóide do Lajedo (eNd(2208) = - 1,7; TDM = 2,6 Ga; 87Sr/85Sri = 0,70322), Granitóide Gentio (eNd(2066Ma) = - 10,8; TDM = 3,0 Ga; 87Sr/85Sri = 0,70021), Quartzo Diorito Dores do Campo (eNd(2198Ma) = - 0,1; TDM = 2,6 Ga; 87Sr/85Sri = 0,70445), Quartzo Diorito do Brito (eNd(2221Ma) = - 0,45; TDM = 2,6 Ga; 87Sr/85Sri = 0,70500), Granodiorito Brumado de Baixo (eNd(2218Ma) = - 0,68; TDM = 2,6 Ga; 87Sr/85Sri = 0,72726) e Granodiorito Brumado de Cima (eNd(2187Ma) = - 0,66; TDM = 2,5 Ga; 87Sr/85Sri = 0,73075). A integração dos dados geoquímicos, geocronológicos e isotópicos permitiu diferenciar a existência de dois conjuntos distintos, a norte e ao sul da ZCL. Os plutons: Brito, Brumado de Cima, Nazareno, Itutinga, Brumado de Baixo, Lajedo e Quartzo Diorito Dores do Campo, situados ao sul da zona de cisalhamento do Lenheiro, possuem uma contribuição de magmas paleoproterozóicos com baixa contaminação por materiais de curta vivência crustal. Esses plutons se enquadram na primeira etapa evolutiva do Cinturão, entre 2220 Ma e 2198 Ma. Os plutons Cassiterita, Brumado, Fé e Glória distribuídos ao norte desta ZCL, considerados da \"Fase Arco\" sugerem maior interação de magmas proterozóicos com componentes arqueanos relativamente ao outro conjunto isotópico; e uma cristalização tardia com relação ao grupo anterior. Já os plutons Ritápolis (2121 ± 7 Ma) e Mama Rosa situados neste mesmo bloco tectônico a norte da falha do Lenheiro, indicam uma maior interação de componentes arqueanos com magmas proterozóicos, com relação aos dois grupos anteriores, e no contexto evolutivo do Cinturão esses plutons se enquadram na fase sin- a tardi-colisional. E finalmente, o Granitóide Gentio, situado na porção sul da Zona de Cisalhamento do Lenheiro, possui uma maior interação dos magmas proterozóicos com componentes de crosta arqueana, e um posicionamento na fase final da evolução do Cinturão Mineiro, junto com as intrusões graníticas pós-tectônicas. Isto reforça a hipótese de haver pulsos magmáticos de caráter tectônico distinto, no âmbito da Província Sul Mineira. Adicionalmente, dados comparativos de idade U-Pb e TDM, do Cinturão Mineiro com a porção paleoproterozóica ao norte do Cráton São Francisco, indicam que a Orogênese Transamazônica foi um pouco mais precoce no Cinturão. Os protólitos das rochas plutônicas de ambas as porções tiveram uma gênese a partir de uma mistura de magma paleoproterozóico juvenil com componentes crustais arqueanos em maior ou menor quantidade. / The study area is located in the southern border of the São Francisco Craton, Mineiro Belt. This portion comprises part of the Sul Mineira Province. In this context occurs medium to high metamorfic grade Archean and Paleoproterozoic terrains mosaic and granite-greenstone associations. The plutonic bodies, studied in this work, make part of volumous paleoproterozoic plutonism intrusive in to Nazareno greenstone belt (Archean) and Rio das Mortes greenstone belt (Proterozoic). The Lenheiro shear zone (LSZ delimits these greenstone belts: Nazareno (in the south) and Rio das Mortes (in the north); as well as the Paleoproterozoic plutons. The plutons chose for this work are: Fé Granitic Gneiss, Mama Rosa Granite, Cassiterita Tonalite/Trondhjemite, Ritápolis Granite, Brumado Diorite e Glória Quartz-Monzodiorite, located in the north LSZ; and: Lajedo Granitoid, Gentio Granitoid, Dores do Campo Quartz-Diorite, Brito Quartz-Diorite, Brumado de Baixo Granodiorite and Brumado de Cima Granodiorite, located in the south LSZ. Their petrographic characteristics are was follow: Fé Granitic Gneiss (monzogranite to sienogranite), Mama Rosa Granite (monzogranite), Cassiterita Tonalite/Trondhjemite (tonalite to granodiorite), Ritápolis Granite (tonalite, granodiorite, monzogranite and syenogranite), Brumado Diorite (diorite, quartz-diorite and tonalite), Glória Quartz-Monzodiorite (quartzdiorite, quartz-monzodiorite and tonalite), Lajedo Granitoid (granodiorite), Gentio Granitoid (kfeldspar granite), Dores do Campo Quartz-Diorite (quartz-diorite), Brito Quartz-Diorite (quartzdiorite), Brumado de Baixo Granodiorite (granodiorite to monzogranite) and Brumado de Cima Granodiorite (granodiorite to monzogranite). The Fé, Mama Rosa and Lajedo plutons have peraluminous/metaluminous composition, the Dores do Campo Quartz-Diorite is metaluminous and the Gentio Granitoid is peraluminous. The Fé Granitic Gneiss, Mama Rosa Granite and Gentio Granitoid alternate calc-alcaline trend to shoshonitic trends, in terms of K2O contents. The Lajedo Granitoid is calcic-alkaline and Dores do Campo Quartz-Diorite alternate toleiitic and calcic-alkaline caracteristics. We have obtained U-Pb ages (zircon) for the following rocks: Fé Granitic Gneiss (2191 ± 9 Ma), Lajedo Granitoid (2208 ± 26 Ma), Gentio Granitoid (2066± 10 Ma - minimum age) and Dores do Campo Quartz-Diorite (2198 ± 6 Ma). The geochemistry, geocronology and isotope information consent define the existence of two groups of plutons, in the north and south of LSZ. The plutons: Brito, Brumado de Cima, Nazareno, Itutinga, Brumado de Baixo, Lajedo and Quartzo Diorito Dores do Campo, located in south of LSZ, have Paleoproterozoic magma contribution with reducted contamination of short crustal life materials. These plutons belong to the first evolutive stage of the Mineiro Belt, between 2220 Ma and 2198 Ma. The plutons Cassiterita, Brumado, Fé and Glória located in north of LSZ, considered of the \"Arc Stage\" have significant Paleoproterozoic magma interation with Archean components compared to the other isotopic group; and a late cristalization time, between the north and the south group. The Ritápolis (2121 ± 7 Ma) and Mama Rosa plutons (north of the Lenheiros fault) display strong intersection with Archean components, and are tecnically related to the syn- to late- collision stage of the Mineiro belt evolution. The Gentio pluton shows similar isotopic characteristics, but it belongs to the pos-tectonic stage. Finaly, the U-Pb and ; TDM ages of the Mineiro belt plutons, compared with the Paleoproterozoic plutons that occursin the northen São Francisco craton, reveal that significant time differences took place during the Transamazonian orogeny. In addition, the auxilable isotopic characteristics of these plutons suggest the important role of mixing of Paleoproterozoic magmas and Archean protholits during magma genesis.
106

Geologia estrutural da aba norte da estrutura divergente do rio Paraíba do Sul: seções Três Rios (RJ) - Matias Barbosa (MG) e Barra do Piraí - Conservatório (RJ) / Structural geology of northern limb of the Paraiba do Sul river divergent structure: cross-sections Três Rios (RJ) - Matias Barbosa (MG) and Barra do Piraí - Conservatória (RJ)

Vicente, Leticia Constantino 30 September 2008 (has links)
O presente trabalho trata da geologia estrutural de uma fração da Província Mantiqueira Central, correspondente no flanco norte da divergência em leque da calha do rio Paraíba do Sul. O levantamento de duas seções geológico-estruturais (seção Três Matias - Matias Barbosa e seção Barra do Piraí - Conservatória) permitiu a caracterização das principais feições geométricas e cinemáticas na região. Além disso, a análise da orientação preferencial do retículo cristalino do quartzo em amostras coletadas ao longo dos perfis permitiu discutir os mecanismos de deformação e relacioná-los a um ambiente de crosta inferior. Na seção Três Rios - Matias Barbosa foram reconhecidos três domínios estruturais distintos. Em todos eles a direção da foliação permanece orientada NE-SW, mas o ângulo de mergulho diminui à medida que se distancia da zona de cisalhamento, tornando-se uma foliação de baixo ângulo no domínio II, e de mergulho moderado no domínio III. A lineação mineral e de estiramento apresenta-se de caimento baixo nos domínios I e II, tornando-se oblíqua no domínio III, com caimento para NE. Em cada domínio observam-se, em escala de afloramento, estruturas geometricamente distintas. Os indicadores cinemáticos são compatíveis em ambos os domínios, mostrando movimentação destral em plano horizontal, e de topo para SW, nos planos de baixo ângulo. Na seção Barra do Piraí - Conservatória, foram reconhecidos cinco domínios estruturais (I, II, III, IV e V). Os domínios I e V são caracterizados por uma foliação de alto ângulo na direção NE-SW e lineação direcional. Os domínios II, III e IV são caracterizados por uma foliação também na direção NE-SW, mas com o mergulho variando de baixo ângulo para NW, subvertical e baixo ângulo para SE, respectivamente. Os indicadores cinemáticos nos domínios I, III e V são coerentes com movimentação destral, mas não foram observados nos domínios II e IV. Da mesma forma como foi observado na seção Três Rios -Matias Barbosa, observa-se aqui, também, em escala de afloramento, intercalação de estruturas geometricamente distintas. Os dados microestruturais e de orientação preferencial do retículo cristalino mostram variação na predominância de cisalhamento simples e cisalhamento puro nos diferentes domínios. Além disso, são registradas mudanças na ativação dos sistemas de deslizamento que podem estar relacionadas tanto com a existência de um gradiente termal durante a deformação ao longo das duas seções, como devida à manutenção de alta temperatura mesmo após a deformação, caracterizando o processo de annealing. A mudança na geometria das estruturas pode ser caracterizada em termos da razão entre os componentes de cisalhamento simples e cisalhamento puro. Além disso, considerando-se as modelagens teóricas disponíveis, estas estruturas podem ser consideradas cinematicamente compatíveis em termos de um modelo de evolução tridimensional. Ambas as seções sugerem a existência de regiões resultantes da extrusão tectônica em regime transpressivo, correspondentes ao domínio II da seção Três Rios (RJ) - Matias Barbosa (MG) e os domínios II, III e IV da seção Barra do Piraí - Conservatória (RJ). A mudança lateral e a relação de sobreposição das estruturas são interpretadas como resultantes da partição espacial e temporal da deformação. Assim, sugere-se que as estruturas nesse setor da Província Mantiqueira foram geradas em um regime de deformação transpressivo não-confinado em uma evolução tectônica simples. / This study is about the structural geology of a portion of the Central Mantiqueira Province which corresponds to the north side of the structural divergence of the Rio Paraíba do Sul valley. Two geological cross-sections (Três Rios - Matias Barbosa and Barra do Piraí - Conservatória) provided geometrical and kinematics data. Lattice preferred orientation of quartz showed deformation mechanisms that affected these rocks in the lower crust. Three distinct structural domains were recognized in the Três Rios - Matias Barbosa cross-section. They present NE-SW foliation with decreasing dip distant from the shear zone, low dip at domain II and moderate dip at domain III. The mineral and stretching lineation present low plunging at domains I and II and significant NE oblique dip at domain III. In all domains of the meso-scale there are observed distinct geometrically structures. Kinematics indicators are likely in all domains showing horizontal dextral sliding and top-to SW from low dip. Five distinct domains were observed in the Barra do Piraí - Conservatória crosssection. Domains I and V are characterized by NE-SW steeply dipping foliation and strike lineation. Domains II, III and IV show NE-SW foliation presenting NW low dip, subvertical and SE low dip, respectively. Kinematics indicators at domains I, III and V show dextral shear sense, while in the domains II and IV, they were not observed. As in Três Rios - Matias Barbosa cross-section, meso-scale distinct geometrical structure intercalation were observed. Microstructural data and lattice preferred orientation present variation in simple shear and pure shear for different domains. A change on the slip systems can be associated to thermal gradient along cross-section during deformation or to high temperature maintenance after deformation, characterizing an annealing process. Changes on geometrical structures can be characterized as a relationship between simple shear and pure shear. Comparing these structures with theoretical modeling, we can consider them to be kinematics likely in a three-dimensional evolution model. Both crosssections suggest extrusion in transpressional tectonic pattern at domain II in Três Rios (RJ) - Matias Barbosa (MG) cross-section and domains II, III and IV in Barra do Piraí - Conservatória (RJ) cross-section. Lateral changes and structures overlapping are interpreted as a result of spatial and temporal partition of deformation. The presented data suggest that Mantiqueira Province structures in the studied area were generated by a non-confined transpressional deformation pattern in a simple tectonic evolution.
107

Ruination as invention: reconstructions of space and time in a deindustrial landscape

Irving, Brook Alys 01 May 2015 (has links)
This dissertation argues that the symbolic force of deindustrial Rust Belt decline is expressed through patterns of rhetorical invention, what I call ruination rhetorics. Ruination, I argue, works to construct divergent orientations toward space and time in representations of the Rust Belt. I trace these orientations as a way of charting the contours of how we understand domestic urban decay in our contemporary political and economic climate. This project argues that ruination's inventive force hints at a number of thematics including: ruination as urban waste; ruination as a claim to forms of nostalgia and authenticity; ruination as a linkage between temporal configurations of the past and the present; and ruination as a narrative form enabling what I call a "melancholic" rhetorical style. In all of these instances, ruination supports differentiated orientations toward time and space, creating temporal and geographical connections and boundaries through rhetorical manipulations. In this way, the times and spaces of and for industrial ruination shift, and in so doing, their discursive manifestations elucidate the diversity and instability of spatio-temporal structures. Conceptually, I argue that ruination shapes an understanding of space and time as fluid concepts, rather than stagnant or pre-determined categories. And by unpacking the ways that ruination traffics in representations of Rust Belt geographies and citizens, we discover an increasingly complex discursive field out of which meaningful relationships to decay and renewal might be forged. In this way, ruination does not weave a cohesive narrative of what the Rust Belt is, where the Rust Belt is, or who does or does not lay claim to its political realities and challenges. Rather, its divergent and contradictory modes of rhetorical invention suggest ruination expresses the incoherencies and compatibilities constitutive of an everyday life lived in the ebbs and flows of a material space that is always-already a site of ongoing decay and renewal.
108

Nonlinear dynamics of one-way clutches and dry friction tensioners in belt-pulley systems

Zhu, Farong. January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 163-170).
109

Geochemical study of the Mesoproterozoic Belt-Purcell Supergroup, western North America : implications for provenance, weathering and diagenesis

Gonzalez-Alvarez, Ignacio Jose 04 January 2006
Provenance in the lower Belt-Purcell Supergroup is constrained based on geochemical systematics and chemical monazite ages of argillites and sandstones. Rare earth element (REE), Cr-Ni, and Th/Sc-Sc systematics is equivalent for both facies and consistent with a dominantly post-Archean source area. Detrital monazite chemical ages restrict major provenance for the Appekunny and Grinnell sandstones and argillites to Paleoproterozoic terranes at ~1800-1600 Ma, minor contributions at ~1600-1500 Ma, and marginal contributions from Archean terranes at ~2600, likely in Laurentia. Similar detrital age spectra for monazites of argillites and sandstones of the Appekunny Formation are consistent with a common provenance for the two facies.</p> <p>The Belt-Purcell sequence records three major diagenetic stages displayed in argillites and sandstones: (1) K-addition and rare earth element post-Archean upper continental crust (PA-UCC)-like pattern; (2) a stage characterized by heavy REE enrichment relative to light REE and HFSE fractionation, and U and Ce mobility; and (3) local dolomitization with REE and high field strenght elements (HFSE) mobility. REE and HFSE mobility are interpreted as the result of oxidized alkaline brines developed by dissolution of evaporites. Monazites from the Appekunny and Grinnell formations differ compositionally and texturally in two groups. Rounded or inclusions with ages >~1400 Ma, interpreted as detrital, have higher Th2O, Y2O3 and lower LREE/HREE contents than euhedral individual monazite grains with chemical ages <~1400 Ma that posses opposed compositional characteristics, and viewed as diagenetic. Monazites that span <~1400 to 300 Ma could be the result of basinal brine activity during stages (2) and (3). </p> <p>Chemical index of alteration (CIA) for argillites and sandstones, corrected for a diagenetic K-addition average 73 and 66 respectively. These results, coupled with correlation of CIA with Eu/Eu*, low K/Cs ratios, and low Sr, Ca, and Na relative to PA-UCC, could be interpreted as the result of an moderate weathered provenance in a hot, wet climate being drained by a large-scale river system. Presence of minor pristine feldspars lowers the CIA values, and may signify minor contributions from proximal source with short-river transport under the arid to semi-arid climate in the depositional setting. Moderate to intense weathering of the larger provenance may be associated with elevated levels of atmospheric CO2 degassed from a mantle plume implicated in the rifting of the supercontinent Columbia at ~1500 Ma.
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Do Seat Belt Laws Drive Up Insurance Premiums?

Posner, George 01 January 2012 (has links)
If you have to wear a seat belt when you drive, are you safer? Intuitively, it may seem that the answer is yes. After all, if you are wearing a seat belt and get in an accident, you are half as likely to die, and 62% of fatal accident victims were not wearing seat belts at the time of accident. The Centers for Disease Control and Prevention, the National Highway and Transportation Safety Administration, the Governors' Highway Safety Administration, and many other organizations highly recommend wearing seat belts. The NHTSA claims that in 2010 alone, approximately 12,500 deaths were prevented by seat belt use alone. Seat belt laws clearly reduce the chance of death to vehicle occupants in a given auto accident. In response to these findings, the federal government has made the release of highway funds to states contingent on the passage of state laws mandating seat belt adoption. Laws mandating seat belt use, along with extensive campaigns to raise public awareness, have caused seat belt use to rise from 69% in 1998 to 88% in 2009. As of this writing, laws mandating the use of seat belts when driving have been passed in every state save New Hampshire. Intuitively, this should make roads safer because seat belts make an accident more survivable. Does wearing a seat belt, however, make that accident more likely to occur in the first place? If a driver wears a seat belt now and I didn't before, does he feel safe enough to take more risk? In this paper, I examine this question using insurance premiums as a proxy for the likelihood of an accident. The rest of the paper is organized as follows. Section 2 offers background information, including a framework with which to interpret a driver’s actions and a review of the relevant literature. Section 3 contains details on the data analyzed. Section 4 covers the results of my preliminary data analysis, model specifications, and robustness checks. Section 5 concludes.

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