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Madeira, Gustavo Oliveira. "Estudo da evolução orbital de partículas em ressonância de corrotação e Lindblad e sob influência de satélites coorbitais : aplicação aos arcos planetários /." Guaratinguetá, 2019. http://hdl.handle.net/11449/180953.
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Orientador: Silvia Maria Giuliatti Winter<br>Resumo: Orbitando Saturno encontram-se Anthe, Methone e Aegaeon, três pequenos satélites coorbitais a arcos planetários e em ressonância de corrotação excêntrica com o satélite Mimas, do tipo 10:11 para o arco de Anthe, 14:15 para o arco de Methone e do tipo 7:6 para o arco do anel G (arco coorbital ao satélite Aegaeon). Neste trabalho é estudada a dinâmica de partículas micrométricas em ressonância de corrotação excêntrica, sob o efeito de forças perturbadoras (força de radiação solar e arrasto do plasma) e da influência gravitacional de pequenos satélites. A ressonância de corrotação excêntrica m + 1:m é responsável por criar m sítios nos quais as partículas permanecem azimutalmente confinadas. Quando incluídos satélites hipotéticos nos sítios, as partículas rapidamente colidem como estes, de modo que os sítios ficam vazios em algumas centenas de anos. Ainda foi constatado que existe uma correlação entre o tempo de vida das partículas com o tamanho físico do satélite, sendo verificado um aumento do tempo de vida dos sítios com o raio do satélite, para satélites com raios da ordem de metros, passando a decrescer para satélites com raios da ordem de quilômetros. Tal resultado se deve ao fato dos satélites pequenos tenderem a apenas perturbar a órbita das partículas, as quais realizam maiores excursões em relação ao centro do sítio, enquanto satélites maiores confinam as partículas azimutalmente, de modo que estas permanecem em ressonância de corrotação com Mimas e com o satélite. Efe... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: Anthe, Methone and Aegaeon are three tiny saturnian moons. They are coorbital to planetary arcs and are trapped in corotation eccentric resonances with Mimas: 10:11 Anthe’s arc, 14:15 Methone’s arc and 7:6 G ring arc (Aegaeon’s arc). In this work we studied the dynamics of the particles trapped in the corotation eccentric resonances under the effects of dissipative forces (solar radiation force and plasma drag) and coorbitals moonlets. The m + 1:m corotation eccentric resonance creates m sites where the particles will be azimuthally confined for more than 100 thousand years. When satellites are located in the sites, the particles quickly collide with them and these sites are cleaned in a few hundred years. We verified an increase in the lifetime of the sites with the satellites’ radii, for moons with radius of the order of meters, and a decrease in the lifetime with an increase of the satellites’ radii, for kilometer-sized satellites. Satellites with radii of the order of meters only disturb the particles’ orbits, so the particles perform large excursions in relation to the site’s center. Satellites with kilometric radii azimuthally confine the particles, wich remain in resonance with Mimas and with the coorbital satellite. The solar radiation force and plasma drag effects on the semimajor axis remove particles from the azimuthal confinement and the effects on the eccentricity favor collisions with the satellites. The sites of the 7:6, 14:15 and 10:11 corotation resonance, if... (Complete abstract click electronic access below)<br>Mestre
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Lattari, Victor Correa. "Formação de pequenos satélites e anéis de poeira /." Guaratinguetá, 2019. http://hdl.handle.net/11449/181828.
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Orientador: Rafael Sfair de Oliveira<br>Resumo: A formação de alguns arcos dos anéis planetários pode estar relacionada às colisões de partículas interplanetárias com seus satélites, fragmentando-os e produzindo corpos menores. De modo sucessivo, estes fragmentos podem sofrer novas colisões e eventualmente gerar partículas de poeira. Por outro lado, os corpos macroscópicos (da ordem de metros) imersos no anel podem colidir entre si e aglutinar- se de modo a gerar novos objetos maiores. A existência destes arcos é creditada a presença de um satélite perturbador que os confina em um ressonância de corrotação. No caso do arco do anel G de Saturno, este é confinado por uma uma ressonância excêntrica 7:6 de corrotação com o satélite Mimas. Hedman et al. (2010) citam que o arco do anel G é majoritariamente composto por partículas da ordem de micrômetros. Neste caso, as forças perturbativas, tais como a pressão de radiação e a força eletromagnéticas, são significativas e tendem a reduzir o tempo de vida destas partículas nesta região. Para explicar a estabilidade do arco Hedman et al. (2010) utilizaram o pequeno satélite Aegaeon (imerso no arco) que poderia ser uma fonte do material das partículas micrométricas imersas no arco via colisões de partículas interplanetárias com Aegaeon. Entretanto, Madeira et al. (2018) exploraram o efeito da pressão de radiação solar e mostraram que o tempo de vida das partículas micrométricas no arco é menos de 40 anos e que o satélite Aegaeon não poderia ser fonte de material e manter a quantidade... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: Some planetary rings exhibit denser regions called arcs, and the existence of these arcs is credited by the presence of a disturbing satellite that confines the particles in a corotation resonance. The formation of the planetary ring arc can be related with the collisions between interplanetary particles with an embedded satellite, or the break up of a moon into minor bodies. Successively, these bodies may experience new collisions that eventually create dust particles. Meanwhile, the macroscopic bodies can collide among themselves and merge, resulting in large bodies. For the Saturn’s G ring’s arc, it is confined by a 7:6 corotation resonance with the satellite Mimas. Hedman et al. (2010) showed this arc is composed mostly of micrometers particles, a configuration that perturbative forces are significant and decrease the lifetime of the structure. To explain the stability of this arc, they proposed that the satellite Aegaeon could be a source of the material of the dust by collisions within interplanetary particles. However, Madeira et al. (2018) studied the solar radiation pressure and showed that the lifetime of the particles in less than 40 years and that the satellite Aegaeon cannot be a source. Therefore, another mechanism is necessary to explain the arc. To do so, one can use information derived by the LEMMS (Magnetospheric Imaging Instrument’s LowEnergy), an instrument from that Cassini spacecraft that detected an energy drop from electrons in this region, inferring t... (Complete abstract click electronic access below)<br>Mestre
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Shea, Erin Kathleen McLaren. "Arc magmatism at different crustal levels, North Cascades, WA." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87510.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2014.<br>Some pages printed landscape orientation. Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 299-311).<br>The mechanisms of magma ascent and emplacement inferred from study of intrusive complexes have long been the subject of intense debate. Current models favor incremental construction, but much of this work has been focused on a single crustal level. However, the study of magmatism throughout the crust is critical for understanding how magma ascends through and intrudes surrounding crustal material. I present new field, geochronologic and geochemical data from three intrusive complexes emplaced at a range of crustal depths in the Cretaceous North Cascades magmatic arc. Integration of geological mapping and high-precision U-Pb TIMS geochronology allows me to demonstrate variable styles of intrusion in different complexes: Assembly of the Black Peak intrusive complex occurred via a series of small (<1 km 3) magmatic increments from ca. 91.7 Ma to 86.8 Ma. My data indicate each of these increments were emplaced and solidified without major assimilation of country rock. The Seven- Fingered Jack intrusive complex, emplaced around ~20-25 km, preserves a similar record of intrusion between ca. 91.8 Ma and 90.5 Ma. Significant compositional variability and antecrystic zircons suggest that the Seven-Fingered Jack represents the remnants of mid-crustal magmatic conduit. Geochronology from the deep-crustal (~25-30 km) Tenpeak intrusive complex, intruded between ca. 92.2 Ma and 89.5 Ma, suggests that plutons comprising the complex were assembled rapidly (<300 ka). These intrusive complexes represent different parts of an arc system, including deep- and shallow-crustal intrusions and a magmatic conduit. I propose a model where increments of magma migrated through the crust in magmatic conduits that were active multiple times. These conduits focused rising magma and served as a crustal filter. Geochronologic and isotopic variability between the Tenpeak and Black Peak intrusive complexes are likely a result of this filtering process and the vastly different conditions in the deep and shallow crust.<br>by Erin Kathleen Shea.<br>Ph. D.
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Sisson, Thomas W. "Field, geochemical, and experimental studies of aluminous arc magmas." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/58230.
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Booth, Mark, William R. F. Dent, Andrés Jordán та ін. "The Northern arc of ε Eridani’s Debris Ring as seen by ALMA". OXFORD UNIV PRESS, 2017. http://hdl.handle.net/10150/625481.
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We present the first Atacama Large Millimeter/submillimeter Array (ALMA) observations of the closest known extrasolar debris disc. This disc orbits the star is an element of Eri, a K-type star just 3.2 pc away. Due to the proximity of the star, the entire disc cannot fit within the ALMA field of view. Therefore, the observations have been centred 18" North of the star, providing us with a clear detection of the Northern arc of the ring, at a wavelength of 1.3 mm. The observed disc emission is found to be narrow with a width of just 11-13 AU. The fractional disc width we find is comparable to that of the Solar system's Kuiper Belt and makes this one of the narrowest debris discs known. If the inner and outer edges are due to resonances with a planet then this planet likely has a semi-major axis of 48 AU. We find tentative evidence for clumps in the ring, although there is a strong chance that at least one is a background galaxy. We confirm, at much higher significance, the previous detection of an unresolved emission at the star that is above the level of the photosphere and attribute this excess to stellar chromospheric emission.
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Robe, Françoise R. (Françoise Romain). "Sea, sun, and shear : a recipe for precipitating convection, tropical rainbands, and hurricane spiral arms." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/17416.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1996.<br>Includes bibliographical references (p. 235-242).<br>by Françoise R. Robe.<br>Ph.D.
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Saal, Alberto Edgardo. "Petrology and geochemistry of intra-back arc basalts from the Argentine Andes." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/57753.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1994.<br>Includes bibliographical references (leaves 50-63).<br>by Alberto Edgardo Saal.<br>M.S.
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Brunner, Anna Elizabeth. "Decarbonization related to continental arc magmatism as a possible mechanism for Cretaceous warming." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/114357.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 53-56).<br>Elevated concentrations of CO₂ have been proposed as the reason that the Cretaceous climate was 6-14°C warmer than the present, however the source of Cretaceous CO₂ is unknown [Barron, 1983]. This study examines the possibility of continental arc magmatism as a mechanism for CO2 release, specifically as a volatile produced during crustal assimilation and contact metamorphism of carbonates around plutons. Bedrock maps of the North American Cordillera (a region of active continental arc magmatism during the Cretaceous), the relative locations of the carbonates, the Cretaceous plutons, and the calculated "decarbonation zones"around the plutons. These measurements were then input in a thermal and petrologoical model in order to estimate the quantity of CO₂ released by continental arc magmatism. Testing a number of cases with varying parameters, the model found the arc-magmatism-induced temperature difference between the present and Cretaceous global climates to have a lower limit of [Delta]T < 1°C and an upper limit of 5.1 < [Delta]T < 12.3°C. Decarbonation from continental arc magmatism is shown to be a possible mechanism of paleoclimatic warming, and more work is required to either confirm or refute the hypothesis.<br>by Anna Elizabeth Brunner.<br>S.B.
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Kennedy, Allen Ken. "The geochemistry of undersaturated arc lavas from the Tabar-Feni island groups, Papua New Guinea." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/54329.
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Matzel, Jennifer E. Piontek 1973. "Rates of tectonic and magmatic processes in the North Cascades continental magmatic arc." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30292.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2004.<br>Includes bibliographical references.<br>Continental magmatic arcs are among the most dynamic. geologic systems, and documentation of the magmatic, thermal, and tectonic evolution of arcs is essential for understanding the processes of magma generation, ascent and crustal growth. The primary goal of this research is to determine rates of tectonic and magmatic processes in the mid to deep crustal levels of the crystalline core of the Cretaceous North Cascades arc. This region was selected for study because it preserves a -10-40 km depth-section through the arc, which allows an assessment of magmatic and structural processes over a range of crustal levels. The relatively young age of the arc (ca. 100-45 Ma) and the inherent high-precision of U-Pb zircon dates permit absolute uncertainties of <100 ky. Meta-supracrustal rocks of the Cascades core record some of the highest pressures obtained in the North American Cordillera. The timing of deposition and metamorphism of the 9-12 kbar Swakane Gneiss constrain tectonic burial models and the timescales of large crustal displacements within an arc setting. These models involve rapid burial (-7 mm/yr) of a fore- or back-arc basin from ca. 73-68 Ma. Nd isotopic signatures of all meta-clastic terranes of the Cascades core reflect mixing of arc- and craton-derived sediment, and the Swakane Gneiss has the most isotopically-evolved signature of these terranes. Nd isotopic signatures of plutons that intrude the core lack evidence of melting of this isotopically-evolved unit. 40Ar/39Ar and U-Pb thermochronologic data define regional cooling patterns that suggest mid- to Late Cretaceous exhumation coincident with contraction and crustal thickening at the deepest levels of the core, followed by Early Tertiary extension.<br>(cont.) High-precision U-Pb geochronology reveals internal complexities inherent in the construction of an intrusive magmatic system. The Mount Stuart batholith was constructed over a ca. 5.6 Myr time period with four punctuated intervals of magma emplacement, whereas the Tenpeak intrusion was emplaced in a more continuous process over ca. 2.7 Myr time period. U-Pb zircon dates from two elongate intrusions, the Seven- Fingered Jack and Entiat suites, suggest that they were constructed from multiple magmatic sheets that were partially homogenized at the level of emplacement.<br>by Jennifer E. Piontek Matzel.<br>Ph.D.
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Klein, Benjamin Zachary. "Processes and rates of arc crust growth and differentiation in the Southern Sierra Nevada crustal section." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/121759.
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Thesis: Ph. D. in Geology, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2019<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references.<br>This thesis presents a multidisciplinary investigation of the processes and timescales for the construction of arc crust, with a focus on the exposed crustal section in the southernmost Sierra Nevada Batholith, California. This section exposes plutons that were emplaced at pressures ranging from 3-10 kbars, as well as metamorphic wall rocks. Chapters 1 and 2 represent focused studies of the Bear Valley Intrusive Suite (BVIS), the dominant igneous component of the crustal section. Chapter 1 presents new magmatic structural data and whole rock geochemical data that highlight a discontinuity in the BVIS between a lower crust dominated by originally shallowly lying mafic cumulates and an upper crust dominated by steeply oriented felsic intrusives. These observations are used to constrain the thermal state of the arc during the emplacement of the BVIS. Chapter 2 is a high-precision CA-ID-TIMS U/Pb zircon geochronology study of the BVIS.<br>This study shows that the entire BVIS was emplaced within 1.1 million years, and thus represents the highest documented (intrusive) subduction zone magmatic flux. Chapter 3 focuses on the contribution of the metamorphic wall-rocks to the observed crustal section. Using detrital zircon geochronology, I argue that these wall-rocks preserve an inverted stratigraphy that is most easily explained if these sediments were first subducted and subsequently returned as relaminated material, which would make these materials the first in situ example of relaminated sediments. Chapters 4 and 5 present broader studies of subduction zone processes in space and time. In Chapter 4, I present a study based on a global compilation of modern arc lavas.<br>This study develops new proxies that use distinctive major element trends produced by fractionating magmas to qualitatively constrain the hydration state and initial fractionation pressure of differentiating magmas, and finds that magmas in continental arcs typically evolve at wetter and higher-pressure conditions compared to island arcs. Finally, Chapter 5 investigates the dynamics of subducted slabs through Earth's history and finds that, based on anticipated higher mantle temperatures and concomitant thicker, more mafic oceanic crust, subducted slabs in the Archean are unlikely to have stagnated within or immediately below the mantle transition zone.<br>by Benjamin Zachary Klein.<br>Ph. D. in Geology<br>Ph.D.inGeology Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences
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Schneider, Julia. "Hope and Hopelessness in Environmental Discourse - Planetary Boundaries contra Ecological Modernisation." Thesis, Malmö universitet, Fakulteten för kultur och samhälle (KS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-23964.
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Med sin grund i klimatutmaningen och en utbredd klimatångest, försöker den här uppsatsen förstå hoppfullhet i miljödiskursen genom en socialkonstruktivistisk lins. En diskursanalys har genomförts av tre videokällor med talare som på olika sätt agerar som röster för miljörörelsen. Materialet som har analyserats i det här arbetet är ett TED-talk, ett tal från Climate Innovation Summit 2016 och ett avsnitt av det svenska tv-programmet Idévärlden. Syftet med studien har varit att undersöka hur en medvetenhet av begreppet Planetens hållbara gränser påverkar hoppfullhet och hopplöshet inom miljödiskursen. Resultatet visade att de flesta talarna tog del av en hoppfull diskurs med en viss tilltro till ekologisk modernisering och att en medvetenhet om Planetens hållbara gränser kan påverka hoppfullhet och hopplöshet på olika sätt. Studien är viktig för att en förståelse för miljödiskursen är ett steg mot att öka miljömedvetet beteende och minska klimatångest i en tid då vi behöver agera mot klimatförändringarna. Studien ger en genomgång av tidigare forskning samt en översiktlig historisk presentation av miljödiskursen och avslutar sedan med reflektion av det egna arbetet och förslag för fortsatta studier.<br>In light of the climate challenge and widespread climate anxiety, this thesis seeks to understand hope in the environmental discourse through a lense of social constructivism. A discourse analysis has been conducted of three video sources, with speakers who in different ways are voices for the environmental movement. The material investigated in this study is a TED talk, a speech from Climate Innovation Summit 2016 and an episode from the swedish tv-show Idévärlden (eng. The Idea World). The purpose of the study has been to investigate how an awareness of the concept of Planetary Boundaries affects hope and hopelessness within the environmental discourse. It was found that most speakers are part of a hopeful discourse with a belief in ecological modernisation and that an awareness of the concept of planetary boundaries can affect hopefulness or hopelessness in different ways. This is of importance because understanding the environmental discourse is a step towards pro-environmental behaviour and decreasing climate anxiety in a time when we need to take action against climate change. The thesis gives a review of previous research in the field as well as a brief historical presentation of the environmental discourse.
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Tormey, Daniel Richard. "Geology and geochemistry of the active Azufre-Planchon-Peteroa volcanic center (351̊5' S, southern Andes) : implications for Cordilleran arc magmatism." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/39953.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1989.<br>Includes bibliographical references (v. 2, leaves 314-331).<br>by Daniel Richard Tormey.<br>Ph.D.
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Densmore, Casey R. Lieutenant Junior Grade(Casey RIchard Owen). "Development and testing of the AXBT Realtime Editing System (ARES)." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/129026.
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Thesis: S.M., Joint Program in Physical Oceanography (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2020<br>Cataloged from student-submitted PDF of thesis.<br>Includes bibliographical references (pages 129-130).<br>Airborne eXpendable BathyThermographs (AXBTs) are air-launched, single use temperature-depth probes that telemeter temperature observations as a VHF-modulated frequency. This study describes the AXBT Realtime Editing System (ARES), which was developed to receive and quality control temperature-depth profiles with no external hardware other than a VHF radio receiver. The ARES Data Acquisition System performs fast Fourier transforms on windowed segments of demodulated signal transmitted from the AXBT and uses the resulting spectra to identify valid temperature-depth observations. When evaluated using 389 profiles, the ARES data acquisition system produced temperature-depth profiles nearly identical to those generated using a Sippican MK-21 processor, while reducing the amount of noise from VHF interference included in those profiles. The ARES Profile Editor applies a series of automated checks to identify and correct common profile discrepancies, before displaying the profile on an editing interface that provides simple user controls to make additional corrections. When evaluated against 1,177 tropical Atlantic and Pacific AXBT profiles, the ARES automated quality control system successfully corrected 87% of the profiles without any manual intervention necessary. The ARES Data Acquisition and Profile Editing Systems performed exceptionally well when operationally tested with 44 AXBTs during Hurricane Dorian (2019), enabling high resolution observations across key oceanic features including Dorian's cold wake and the Gulf Stream. Necessary future work includes improvements on the automated quality control algorithm and evaluation against a more diverse dataset of temperature-depth profiles.<br>by Casey R. Densmore.<br>S.M.<br>S.M. Joint Program in Physical Oceanography (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution)
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Craddock, Paul R. "Geochemical tracers of processes affecting the formation of seafloor hydrothermal fluids and deposits in the Manus back-arc basin." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/55328.
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Thesis (Ph. D.)--Joint Program in Chemical Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2009.<br>Includes bibliographical references.<br>Systematic differences in trace element compositions (rare earth element (REE), heavy metal, metalloid concentrations) of seafloor vent fluids and related deposits from hydrothermal systems in the Manus back-arc basin (Eastern Manus Basin, EMB and Manus Spreading Center, MSC) are used to investigate processes that affect their formation. Processes responsible for observed differences in fluids and deposits from distinct geologic settings include (a) fluid-rock interaction (with temperature, pressure and crustal composition as variables), (b) magmatic acid volatile input and, (c) local seawater entrainment and mixing with hydrothermal fluids, coupled with sulfide precipitation and metal remobilization. REE distributions in vent fluids in the Manus Basin exhibit a wide range of chondrite-normalized patterns that contrast with the relatively uniform distributions observed in mid-ocean ridge vent fluids. This heterogeneity is attributed to marked differences in fluid pH and fluoride and sulfate concentrations that significantly affect REE solubility. The data indicate that REEs can be used as indicators of the styles of magmatic acid volatile input in back-arc hydrothermal systems. Anhydrite in deposits record the same range of REE patterns, suggesting that REE distributions preserved in anhydrite can be used as indicators of past magmatic acid volatile input. Vent fluid heavy metal and metalloid concentrations also exhibit considerable differences. High metal concentrations in EMB versus MSC vent fluids reflect low pH, largely from input of magmatic acid volatiles (indicated by fluoride concentrations greater than seawater). In EMB, metal concentrations are locally affected by dissolution of previously deposited sulfide owing to low pH conditions affected by magmatic acid volatile input or seawater entrainment and mixing with hydrothermal fluid that leads to sulfide precipitation and secondary acidity generation.<br>(cont.) Massive sulfide deposits in the Manus Basin exhibit a wide range of mineral compositions and heavy metal enrichments. The formation of Zn-rich (sphalerite/wurtzite) deposits in the MSC and of Cu-Fe and Cu-As-rich (chalcopyrite, tennantite) deposits in the EMB reflects differences in the conditions of sulfide precipitation (temperature, pH) and in metal concentrations. The data suggest that heavy metal and metalloid distributions in massive sulfide deposits can be used as indicators of the conditions of vent deposit formation.<br>by Paul R. Craddock.<br>Ph.D.
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Damerham, Oscar. "Wrong Side of the Ridge: Charting the Urban Fabric of the Countryside." Thesis, Malmö högskola, Fakulteten för kultur och samhälle (KS), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-22372.
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Echoing through the lecture theatres, conference halls and pages of the contemporary Urban Studies discourse is the oft-repeated refrain that today over half the world’s population live in urban areas, and that by 2050 this proportion is expected to be upwards of 70%. The place of the leftover 50% of people inhabiting a vast and seemingly forgotten 98% of the planet’s rural territory is externalised, apparently lying outside the purview of marching urbanisation. Yet the theory of ‘Planetary Urbanisation’ has emerged in recent years positing a contentious epistemological questioning of Urban Studies’ focus sites, objects and processes. In this it argues for a reorientation of the field towards the ignored rural hinterlands of ‘extended urbanity’ falling under the influence of the fluid process of urbanisation which is transforming the countryside through processes of rationalisation, functionalisation and disintegration. Critiqued as overly abstract, empirically shallow and puritanically ignoring form, this paper investigates and experiments with the theory of planetary urbanisation in a grounded study of a corridor of the Swedish countryside and the village of Röstånga. It does so by a concrete, detailed and dualistic approach to sites of extended urbanisation, integrating both form and process in its analysis. This research exercises this analysis through extricating the city-bound flâneur out into the non-city through a phenomenological 60km, 2 day walk from the city of Malmö to Röstånga. Arriving in Röstånga, this paper then turns its attention to multiple, triangulated methodologies of mapping, observations and interviewing in order to bind our flâneur reflections to the built environment of rurality. In doing so, this research details a changing spatial and social landscape of the Skåne countryside and the village of Röstånga with results exposing an urbanised rurality of hybridity, control and decay and a village of operationalised suburbia, of an externally orientated centre and of disparate social innovations. A discussion of these results then exposes a rural realm simultaneously surrendering to its new reality of extended urbanity and desperately searching for meaning and purpose within it; a landscape wilting under what this paper terms as the shadow of post-political urbanisation. This research than calls for ‘politics of the possible’ in a re-politicisation of the rural and concludes by challenging planners, architects and governments to re-imagine alternatives for this vital if forgotten space.
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Mohamed, Ajmal Khan. "Métrologie optique en hypersonique à haute enthalpie pour la rentrée atmosphérique." Habilitation à diriger des recherches, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00829327.
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Ce document synthétise mes actions de recherches dans la métrologie optique pour l'hypersonique à haute enthalpie rencontré lors d'une rentrée atmosphérique. Je présente en début de ce document la problématique de la rentrée atmosphérique dont la maîtrise est primordiale pour le retour sur Terre d'un vol habité ou d'une sonde de retour d'échantillons. Je décris ensuite les moyens de mesures servant à caractériser le gaz en écoulement autour d'un véhicule de rentrée en test dans une soufflerie ou en vol de démonstration. En particulier les moyens d'optique linéaire que sont la fluorescence induite par faisceau d'électrons (FFE) ou par laser, la spectroscopie d'absorption ou d'émission et le LIDAR à diffusion Rayleigh.
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Wu, Yu-lung, and 吳昱龍. "Design of Planetary Gear System with Double Circular-Arc Hilical Gear." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/82683420792134468931.
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碩士<br>正修科技大學<br>機電工程研究所<br>95<br>This paper studied and improved a three stage planetary gear winch with double circular-arc gears. Tooth contact analysis and bending stress were studied by chinese standard double circular-arc gear. The contact stress can be reduced largely because the relative curvature of tooth of double circular-arc gear is smaller than involute gear. The winch with double circular-arc gear can sustain a larger torque than the winch with other type of gear, therefore the size of the winch can be reduced too. Tooth contact stress and bending stress were studied in this paper. Finally, we developed a new tooth profile for double circular-arc gear. This paper improved original double circular-arc gear, developed a new design and applied analysis software to this drive. The processes of design and manufacture were more simple. The advantage of the new drive was confirmed.