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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Thermal Evolution of Moon

Gill, Arshdeep Singh 01 March 2017 (has links)
In August, 2014 three experiments were conducted using infrared systems deployed at White Mountain Research center, CA. The data was acquired for the whole month of August. Teams of 3-4 students from Cal Poly San Luis Obispo and UC Santa Barbara were stationed at the research center for 2-3 days to operate the equipment. The three experiments were:(1) creating spatial-temporal time series of lunar surface temperatures;(2) identifying atmospheric meteor trails;(3) search for meteor impacts on the Moon surface. Out of the three this thesis focusses on experiment 1 and the results from this experiment could also help with the other experiments. We propose to use a thermal infrared camera mounted on a telescope to acquire time-series observations of lunar surface temperatures to get a novel insight into the thermal evolution of the Moon over a complete lunar cycle. Half a lunar cycle would account from morning to night and lasts for approximately 14.75 days. Seeing how the pixel value changes from morning to night the pixel and temperature trends can be observed throughout the day. Apart from that one can get the two temperature peaks that could maybe help to get an estimate for the Thermal inertia of the surface in the presence of Moon regolith. The temperature trends and the thermal inertia could potentially provide some insight for methods that seek to determine the properties of asteroids from ground based observations.
82

Water and volatile element accretion to the inner planets

Sarafian, Adam Robert, 1986- January 2018 (has links)
Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references. / This thesis investigates the timing and source(s) of water and volatile elements to the inner solar system by studying the basaltic meteorites angrites and eucrites. In chapters 2 and 3, I present the results from angrite meteorites. Chapter 2 examines the water and volatile element content of the angrite parent body and I suggest that some water and other volatile elements accreted to inner solar system bodies by ~2 Myr after the start of the solar system. Chapter 3 examines the D/H of this water and I suggest it is derived from carbonaceous chondrites. Chapter 4, 5, 6, and 7 addresses eucrite meteorites. Chapter 4 expands on existing models to explain geochemical trends observed in eucrites. In Chapter 5, I examine the water and F content of the eucrite parent body, 4 Vesta. In chapter 6, I determine the source of water for 4 Vesta and determine that carbonaceous chondrites delivered water to this body. Chapter 7 discusses degassing on 4 Vesta while it was forming. / by Adam Robert Sarafian. / Ph. D.
83

PROJEKTERING AV SOLPANELER PÅ FLERBOSTADSHUS : FALLSTUDIE-FLERBOSTADSHUS RELÄVÄGEN 5 VÄSTERÅS (722 24)

Mujacic, Semir January 2022 (has links)
This work involves preparing a basis for the company Riksbyggen AB and the housing association Brf ASEA-Stan for a possible installation of solar panels on their apartment building on Relävägen 5 (722 24) Västerås. As the company has already installed solar cells on other apartment buildings, a comparison will also be made between the various apartment buildings and what it means in terms of production to install solar cells on Relävägen 5 (722 24) in Västerås. Payoff time and the placement of the solar panels are further factors that have been taken into consideration when designing the solar system at Relävägen 5. From the results a conclusion was made that the apartment building electrical usage may be affected positively by an installation of solar panels. This is because in the summer the building can be self-sufficient while in the winter the building won’t need to buy as much electricity even though the sun hours are very low. The slope of the solar cell system is crucial for the electricity production for an apartment building, which reflects the work’s comparison of the slope and its differences. Interviews, study visits and simulation programs are examples of methods used during the work to facilitate the design of the solar cell system.
84

Frequency Distribution Of Pyroxene Types And A Method To Separate The Composition Of Multiple Pyroxenes In A Sample

Davis, Jimmy Allen 01 January 2007 (has links)
Determining mafic mineral composition of asteroid bodies is a topic reviewed by M.J. Gaffey et al. (2002). The iterative procedure discussed can be implemented as an algorithm, and such efforts revealed weaknesses that are examined in this work. We seek to illustrate the limits of this method and graphically determine its predictions. There are boundaries in the formulae given where the equations break down. In ranges where mafic mixtures are predicted, a method is illustrated that allows a decoupling of these mixtures into the constituents.
85

[en] ECONOMIC FEASIBILITY STUDY OF THE IMPLEMENTATION OF PHOTOVOLTAIC PANELS IN MULTIFAMILY BUILDINGS IN THE CITY OF RIO DE JANEIRO / [pt] ESTUDO DE VIABILIDADE ECONÔMICA DA IMPLANTAÇÃO DE PAINÉIS FOTOVOLTAICOS EM EDIFÍCIOS MULTIFAMILIARES NA CIDADE DO RIO DE JANEIRO

MARIANA VELOSO NOLLYS BRAGA 26 September 2023 (has links)
[pt] Nos últimos anos foi registrado crescimento no consumo energético dos edifícios residenciais, fato marcado pela aceleração gradual do aquecimento global e pelo declínio econômico e ambiental. A eficiência energética vem se apresentando como um vetor estratégico para a sustentabilidade e economia. As tecnologias e a dependência da energia cresceram exponencialmente nos últimos anos, por isso, o tema foi ganhando mais força e atraindo mais consumidores, pois a dependência da população era cada vez maior e não estava sendo acompanhada economicamente. Portanto, essa dissertação tem o objetivo de fomentar através de uma revisão bibliográfica, o progresso da introdução de ações de sustentabilidade na construção. Na presente dissertação são estudadas algumas medidas para ser implementar em um condomínio já existente, localizados no bairro da Tijuca, em Rio de Janeiro, de forma a reduzir consumos energéticos nas áreas comuns dos dois prédios. Foi apresentada uma solução para a produção de energia elétrica a partir de um sistema solar fotovoltaico do tipo On-Grid, analisando o custo de implantação deste sistema, bem como o tempo de retorno do investimento, para finalmente, chegarmos à conclusão sobre a viabilidade da implantação. / [en] Sustainability in the construction sector has gained significant attention in recent years, as the industry recognizes the need for greener and more socially responsible practices. This paradigm shift stems from the understanding that construction activities have a substantial impact on the environment, consuming large amounts of energy, water and raw materials, while generating significant amounts of waste and carbon emissions. To meet these challenges, sustainable construction aims to minimize negative environmental and social impacts throughout a building s life cycle. Incorporating sustainability principles into the construction sector involves several key elements, such as energy efficiency, which plays a key role in sustainable construction. Photovoltaic solar energy aims to minimize dependence on non-renewable energy and reduce greenhouse gas emissions. In conclusion, sustainability in the construction sector involves integrating environmentally responsible practices into all stages of a building s life cycle. The energy performance of buildings has become a concern in Brazil, increasingly focused on sustainability and renewable energy, this concept refers to the measurement of a building s energy efficiency. With energy consumption and greenhouse gas emissions on the rise, it is imperative to assess and improve a building s energy performance in order to mitigate the negative consequences of climate change and reduce the building s energy bills. Several international standards and certifications, such as LEED (Leadership in Energy and Environmental Design) or BREEAM (Building Research Establishment Environmental Assessment Method), provide frameworks for assessing and certifying the energy performance of buildings. These programs emphasize sustainable design, energy efficiency and the reduction of environmental impact, improving the energy and environmental sustainability aspects of buildings. In conclusion, the energy performance of buildings is a critical aspect of achieving sustainability goals and mitigating climate change. Implementing energy-saving measures and adhering to international standards and certifications can lead to improved energy performance and reduced environmental impact.
86

Energy Transfer and Conversion in the Magnetosphere-Ionosphere System

Rosenqvist, Lisa January 2008 (has links)
<p>Magnetized planets, such as Earth, are strongly influenced by the solar wind. The Sun is very dynamic, releasing varying amounts of energy, resulting in a fluctuating energy and momentum exchange between the solar wind and planetary magnetospheres. The efficiency of this coupling is thought to be controlled by magnetic reconnection occurring at the boundary between solar wind and planetary magnetic fields. One of the main tasks in space physics research is to increase the understanding of this coupling between the Sun and other solar system bodies. Perhaps the most important aspect regards the transfer of energy from the solar wind to the terrestrial magnetosphere as this is the main source for driving plasma processes in the magnetosphere-ionosphere system. This may also have a direct practical influence on our life here on Earth as it is responsible for Space Weather effects. In this thesis I investigate both the global scale of the varying solar-terrestrial coupling and local phenomena in more detail. I use mainly the European Space Agency Cluster mission which provide unprecedented three-dimensional observations via its formation of four identical spacecraft. The Cluster data are complimented with observations from a broad range of instruments both onboard spacecraft and from groundbased magnetometers and radars.</p><p>A period of very strong solar driving in late October 2003 is investigated. We show that some of the strongest substorms in the history of magnetic recordings were triggered by pressure pulses impacting a quasi-stable magnetosphere. We make for the first time direct estimates of the local energy flow into the magnetotail using Cluster measurements. Observational estimates suggest a good energy balance between the magnetosphere-ionosphere system while empirical proxies seem to suffer from over/under estimations during such extreme conditions.</p><p>Another period of extreme interplanetary conditions give rise to accelerated flows along the magnetopause which could account for an enhanced energy coupling between the solar wind and the magnetosphere. We discuss whether such conditions could explain the simultaneous observation of a large auroral spiral across the polar cap.</p><p>Contrary to extreme conditions the energy conversion across the dayside magnetopause has been estimated during an extended period of steady interplanetary conditions. A new method to determine the rate at which reconnection occurs is described that utilizes the magnitude of the local energy conversion from Cluster. The observations show a varying reconnection rate which support the previous interpretation that reconnection is continuous but its rate is modulated.</p><p>Finally, we compare local energy estimates from Cluster with a global magnetohydrodynamic simulation. The results show that the observations are reliably reproduced by the model and may be used to validate and scale global magnetohydrodynamic models.</p>
87

The Solar System in perspective : from debris discs to extrasolar planets

Kains, Noé January 2010 (has links)
The last twenty-five years have seen our understanding of the formation and abundance of planets revolutionised, thanks to the first detections of debris discs, and, a decade later, of the first extrasolar planets. Hardly a week now goes by without a planet discovery, and the range of methods used to search for planets has expanded to include techniques that are efficient at detecting different types of planets. By combining the discoveries of the various methods, we therefore have the opportunity to build a picture of planet populations across the Galaxy. In this thesis, I am presenting work done as a basis towards such an effort: first I present work carried out to improve modelling methods for gravitational microlensing events. Since the first microlensing observing campaigns, the amount of data of anomalous events has been increasing ever faster, meaning that the time required to model all observed anomalous events is putting a strain on available human and computational resources. I present work to develop a method to fit anomalous microlensing events automatically and show that it is possible to conduct a thorough and unbiased search of the parameter space, illustrating this by analysing an event from the 2007 observing season. I then discuss the possible models found with this method for this event, and their implication (Kains et al. 2009), and find that this algorithm locates good-fit models in regions of parameters that would have been very unlikely to be found using standard modelling methods. Results indicate that it is necessary to use a full Bayesian approach, in order to include prior information on the parameters. I discuss the analytical priors calculated by Cassan et al. (2009) and suggest a possible form of an automatic fitting algorithm by incorporating these priors in the algorithm used by Kains et al. (2009). Another topic with which this thesis is concerned is the evolution of debris discs around solar-type stars. Late-type stars are expected to be the most numerous host stars of planets detected with the microlensing technique. Understanding how their debris discs evolve equates to understanding the earliest stages of planet formation around these stars, allowing us to truly put our Solar System in perspective. Using the analytical model of Wyatt et al. (2007a), I modelled the evolution of infrared excess flux at 24 and 70 microns using published data of debris discs around solar-type (spectral types F, G and K) stars from the Spitzer Space Telescope. By comparing the results of this study to an analogous study carried out by for A stars by Wyatt et al. (2007b), I find that although best-fit parameters are significantly different for solar-type stars, this may be due to the varying number of inefficient emitters around stars of different spectral types. I suggest that although effective properties are different by an order of magnitude or more, intrinsic properties, while still different, are so by a much smaller factor. These differences may be due to the longer timescales over which solar-type stars evolve, which allow for the formation of larger and stronger planetesimals.
88

INTERDISCIPLINARY CONNECTIONS BETWEEN SCIENCE & THEATRE

Dotson, Jessica N 01 January 2015 (has links)
Abstract INTERDISCIPLINARY CONNECTIONS BETWEEN SCIENCE & THEATRE Jessica Nicole Dotson A thesis submitted in partial fulfillment of the requirements for the degree of Master of Fine Arts at Virginia Commonwealth University. Virginia Commonwealth University, 2015. Major Director: Dr. Noreen C. Barnes, Director of Graduate Studies, Associate Professor of Theatre In the 1990s, astronomer Peter Usher was searching for new ways to teach his introductory astronomy class at Pennsylvania State University. He began to engage his students by searching for astronomical connections from other disciplines. His focus was turned to the arts, especially the works of William Shakespeare. Usher found, while searching through the canon of Shakespeare's work, astronomical references that explored the “new astronomy” of the Elizabethan age (Falk 171). This thesis will explore the writings of Usher, in regard to the astronomy of Hamlet, along with the interdisciplinary connections between art and science in and outside the classroom and museum theatre. From interdisciplinary classroom methods, to arts and scientists collaborating together for the betterment of man-kind, the use of theatre is a way of rediscovering the humanity of human history. The collaboration between the disciplines serves as one of theatre's greatest purposes, to educate and represent a living history of man.
89

Détecteurs micro-bolométriques non refroidis : Application pour une mission spatiale vers les petits corps du système solaire

Brageot, Emily 30 November 2012 (has links)
Les micro-bolomètres non-refroidis bénéficient de développements technologiques récents qui se traduisent par des matrices de plus en plus grandes (1024*768 pixels), pour des pixels de plus en plus petits (17 µm) et de plus en plus sensibles bien que non-refroidis (NETD<60 mK @300 K). L'objectif de cette thèse est d'étudier les détecteurs micro-bolométriques non-refroidis afin de tester leurs capacités en imagerie et en spectroscopie en vue de leur utilisation dans le cadre d'une mission spatiale vers les petits corps du système solaire, dont en particulier la mission Marco Polo R. J'ai étudié le fonctionnement de ces détecteurs en prenant pour exemple le détecteur Nano640Etm de la société Ulis, représentatif de la technologie des micro-bolomètres non-refroidis disponible actuellement. J'ai mesuré la stabilité dans le temps de son signal, l'homogénéité de la matrice du détecteur, et l'influence de différents paramètres de fonctionnement (température du plan focal, temps d'intégration des pixels, gain). La réponse du détecteur est linéaire en fonction de la température de scène à la puissance 4. Les résultats de cette caractérisation m'ont permis de mesurer le NETD du détecteur dans le cadre de cette expérience. J'ai ensuite testé les capacités du détecteur Nano640Etm en imagerie radiométrique calibrée afin d'estimer les erreurs maximales de calibration pour un, deux, ou trois points de calibration placés différemment dans la gamme de température observée / The recent progress of the uncooled micro-bolometer technology has lead to larger detector matrices (1024*768 pixels), with smaller pixel sizes (17 µm) and a higher sensitivity although it is an uncooled technology (NETD<60 mK @300 K). The objective of this thesis is to study uncooled micro-bolometer detectors in order to assess their performance for imagery and spectroscopy within the framework of a space mission towards small bodies of the solar system, including the Marco Polo R mission. I have studied these detectors through the example of the Nano640Etm detector of the Ulis society, which represents well the currently available uncooled micro-bolometer technology. I have measured its signal stability through time, the detector's matrix homogeneity, and the influence of various operating parameters (focal plane temperature, integration time of the pixels, gain). The detector's response is linear as a function of the scene temperature to the power of 4. The results of this characterization allowed me to measure the detector's NETD within this experiment. Then, I tested the Nano640Etm detector's ability to perform calibrated radiometric images in order to estimate the maximum calibration error for one, two, or three calibration points chosen differently within the observed temperature range. Lastly, I assessed the detector's performances for dispersive spectroscopic measurements, using its signal to noise ratio, as a function of the observation wavelength, the scene temperature, and the spectral resolution. The results of these tests are very positive.
90

Datation à haute précision par l'26Al de l'histoire du disque d'accrétion / 26Al high precision dating to constrain the disk accretion history

Luu, Tu-Han 29 November 2013 (has links)
Une période intéressante de l'histoire précoce du système solaire est celle du disque, i.e. la période pendant laquelle se déroule la plupart des processus qui vont conduire du mélange de gaz et de poussières nébulaires à des grains et des planétésimaux, qui seront à un stade ultérieur le matériel de départ pour la formation des embryons planétaires et des planètes. Les témoins de cette époque sont les constituants des météorites primitives (chondrites), principalement les inclusions réfractaires (CAIs) et les chondres. Une des questions centrales dans la compréhension des processus à l'origine des CAIs et des chondres est celle du temps. Les travaux récents de Johan Villeneuve ont permis de démontrer que l'26Al et les isotopes du Mg étaient distribués dans le disque d'accrétion à un niveau d'homogénéité permettant d'utiliser le système 26Al-26Mg comme le chronomètre le plus précis qui soit des évènements qui se sont déroulés lors des 2 ou 3 premiers millions d'années du disque. Le but de cette thèse a été de reprendre toute l'étude de l'26Al avec des mesures de plus haute précision que les mesures existantes, en associant les mesures in-situ (sonde ionique) et en roche totale (HR-MC-ICPMS). Les développements analytiques mis en place pour mesurer les compositions isotopiques en Mg ont été appliqués à l'étude d'olivines réfractaires et de chondres de la météorite Allende, et d'olivines de la pallasite Eagle Station. L'ensemble des données a permis d'apporter des éléments de réponse sur les âges de formation des chondres et de leurs précurseurs, et sur l'origine des olivines réfractaires riches en Mg et la possibilité que celles-ci figurent parmi les précurseurs des chondres / The disk history is a very interesting period of the early Solar System history, i.e. the period during which occurred most of the processes leading from the mixing of nebular gas and dust to grains, and then planetesimals, which will then constitute the starting material for formation of planetary embryos and terrestrial planets. The witnesses of this period that we have in the laboratory are the chondrite constituents, mostly refractory inclusions (CAIs) and chondrules. One of the central questions regarding the processes leading to the formation of CAIs and chondrules is the timing. Villeneuve et al. (2009, 2011) have shown that 26Al and Mg isotopes were homogeneously distributed in the accretion disk, at a level allowing the use of the 26Al-26Mg system as the most precise short-lived chronometer to constrain the 2 or 3 first million years of the disk history. My PhD project aimed at reconsidering the 26Al study with more precise measurements, and by combining in-situ (by MC-SIMS) and bulk (by HR-MC-ICPMS) analyses. The analytical developments we set for Mg-isotope measurements (because of the high precision needed) were then applied to a set of extraterrestrial materials, including Mg-rich isolated olivines and Mg-rich olivines in porphyritic type I chondrules from the Allende CV3 meteorite, as well as chondrules from the same meteorite, and olivines from the Eagle Station pallasite. The whole data set allowed to answer questions such as (i) the origin of chondrule precursor materials and the time of chondrule formation, as well as (ii) the origin of Mg-rich refractory olivines, and the possibility that the latters were part of chondrule precursors

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