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Lunar Mission Analysis for a Wallops Flight Facility LaunchDolan, John Martin 05 November 2008 (has links)
Recently there is an increase in interest in the Moon as a destination for space missions. This increased interest is in the composition and geography of the Moon as well as using the Moon to travel beyond the Earth to other planets in the solar system. This thesis explores the mechanics behind a lunar mission and the costs and benefits of different approaches. To constrain this problem, the launch criteria are those of Wallops Flight Facility (WFF), which has expressed interest in launching small spacecraft to the Moon for exploration and study of the lunar surface. The flight from the Earth to the Moon and subsequent lunar orbits, referred to hereafter as the mission, is broken up into three different phases: first the launch and parking orbit around the Earth, second the transfer orbit, and finally the lunar capture and orbit.
A launch from WFF constrains the direction of the launch and the possible initial parking orbits. Recently WFF has been offered the use of a Taurus XL launch vehicle whose specifications will be used for all other limitations of the launch and initial parking orbit. The orbit investigated in this part of the mission is a simple circular orbit with limited disturbances. These disturbances are only a major factor for long duration orbits and don't affect the parking orbit significantly.
The transfer orbit from the Earth to the Moon is the most complex and interesting part of the mission. To fully describe the dynamics of the Earth-Moon system a three-body model is used. The model is a restricted three-body problem keeping the Earth and Moon orbiting circularly around the system barycenter. This model allows the spacecraft to experience the influence of the Earth and Moon during the entire transfer orbit, making the simulation more closely related to what will actually happen rather than what a patched conic solution would give. This trajectory is examined using Newtonian, Lagrangian, and Hamiltonian mechanics along with using a rotating and non-rotating frame of reference for the equations of motion. The objective of the transfer orbit is to reduce the time and fuel cost of the mission as well as allow for various insertion angles to the Moon.
The final phase of the mission is the lunar orbit and the analysis also uses a simple two body model similar to the parking orbit. The analysis investigates how the orbits around the Moon evolve and decay and explores more than just circular orbits, but orbits with different eccentricities. The non-uniform lunar gravity field is investigated to accurately model the lunar orbit. These factors give a proper simulation of what happens to the craft for the duration of the lunar orbit. Tracking the changes in the orbit gives a description of where it will be and how much of the lunar surface it can observe without any active changes to the orbit. The analysis allows for either pursuing a long duration sustained orbit or a more interesting orbit that covers more of the lunar surface.
These three phases are numerically simulated using MATLAB, which is a focus of this thesis. In all parts of the mission the simulations are refined and optimized to reduce the time of the simulation. Also this refinement gives a more accurate portrayal of what would really happen in orbit. This reduction in time is necessary to allow for many different orbits and scenarios to be investigated without using an unreasonable amount of time. / Master of Science
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Mesmerizing Moon Mysteries: Unraveling the Compositions of Irregular Mare Patches (IMPs) Using Remote ObservationsPiskurich, Nicholas G 01 January 2024 (has links) (PDF)
Compositional characterization of lunar surface features informs our understanding of the Moon's thermal and magmatic evolution. We investigated the compositions of hypothesized volcanic features known as irregular mare patches (IMPs) and their surroundings to constrain formation mechanisms. We used six datasets to assess the composition of 12 IMPs: 1) Moon Mineralogy Mapper (M3) derived spectral parameters (e.g., band center positions, shapes), 2) Lunar Reconnaissance Orbiter (LRO) Diviner Radiometer Experiment (Diviner) measured Christiansen feature (CF) position, 3) SELENE (Kaguya) Multiband Imager (MI) FeO abundance, 4) Clementine 5-band (Ultraviolet/Visible)-derived FeO abundance, 5) LRO Wide Angle Camera (WAC) TiO2 abundance, and 6) LRO Narrow Angle Camera (NAC) derived single scattering albedo. Our analysis suggests that some IMPs are compositionally unique from their surroundings, while other IMPs exhibit ambiguous compositional trends, which is consistent with the wide variety of geologic settings in which IMPs are situated. Large IMPs are similar to surrounding low albedo dark halos, which could suggest a formation association between IMPs and these dark halo materials. Spectral and photometric comparisons suggest that IMPs' compositions are compatible with Apollo 11 and 17 high-Ti mare basalts, as well as a group of synthetic high-Ca pyroxenes. Future remote sensing orbiters with high spatial resolution are essential to resolve the compositions of smaller IMPs as well as the distinct smooth and rough morphological regions within larger IMPs.
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CRUMB - Compact Radio Unit for Moon data Broadcasting / CRUMB - Kompakt Radioenhet för Utsändning av MåndataCarra, Jacopo January 2024 (has links)
In the future, international Lunar missions will include both surface and lava tunnel EVA explorations, together with the collection of soil composition and ground data. Some issues with the realization of these activities are the communication constraints between the astronauts and the ground base on the Moon’s surface (especially in the first phases of Lunar exploration, when the satellite communication network will be under-supplied), and the limited area that a classical ground analyzing scientific instrument can cover. A solution to those issues has already been explored by previous interns at Spaceship EAC, resulting in a set of hardware prototypes communicating via LoRa protocol in an Internet of Things network configuration. The main idea behind these devices is to act both as signal transmitters and receivers, bridging the astronaut’s EVA suit to the ground base, and as a broad sensor network, capable of collecting a large amount of ground data from a vast area (crucial, for example, because of the proven heterogeneity of lunar soil chemical composition between different zones).This thesis explores the feasibility of miniaturizing these prototypes and creating a new set of smaller units with enhanced functionalities and performance. The designed device is called CRUMB (Compact Radio Unit for Moon data Broadcasting), and each unit is capable of communicating to other CRUMBs via LoRa frequencies (868 MHz – standard for European applications) while answering to an IoT mesh protocol. Via an accelerometer sensor, the CRUMB units are also able to send gravimetry data to the rest of the mesh, and to send an emergency communication whenever a moonquake is detected. Moreover, CRUMB’s volume is 92% smaller than its predecessor’s, and it nominally operates with a low power consumption (less than 1 W). / I framtiden kommer internationella månuppdrag att omfatta EVA-utforskning av både ytan och lavatunnlar, tillsammans med insamling av jordsammansättning och markdata. Några problem med att genomföra dessa aktiviteter är kommunikationsbegränsningarna mellan astronauterna och markbasen på månens yta (särskilt under de första faserna av månutforskningen, när satellitkommunikationsnätverket kommer att vara underförsörjt) och det begränsade område som ett klassiskt markanalyserande vetenskapligt instrument kan täcka. En lösning på dessa problem har redan utforskats av tidigare praktikanter vid Spaceship EAC, vilket har resulterat i en uppsättning hårdvaruprototyper som kommunicerar via LoRa-protokollet i en Internet of Things-nätverkskonfiguration. Huvudidén bakom dessa enheter är att fungera både som sändare och mottagare av signaler, som en brygga mellan astronautens EVA-dräkt och markbasen, och som ett brett sensornätverk som kan samla in en stor mängd markdata från ett stort område (avgörande, till exempel på grund av den bevisade heterogeniteten i månjordens kemiska sammansättning mellan olika zoner).I denna avhandling undersöks möjligheten att miniatyrisera dessa prototyper och skapa en ny uppsättning mindre enheter med förbättrade funktioner och prestanda. Den designade enheten kallas CRUMB (Kompakt Radioenhet för Utsändning av Måndata), och varje enhet kan kommunicera med andra CRUMB-enheter via LoRa-frekvenser (868 MHz - standard för europeiska tillämpningar) och samtidigt svara på ett IoT mesh-protokoll. Via en accelerometersensor kan CRUMB-enheterna också skicka gravimetridata till resten av nätet och skicka ett nödmeddelande när en månbävning upptäcks. CRUMB:s volym är dessutom 92% mindre än föregångarens och den nominella energiförbrukningen är låg (mindre än 1 W).
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Solar Wind Proton Interactions with Lunar Magnetic Anomalies and Regolith / Solvindsprotoners växelverkan med månens magnetiska anomalier och ytaLue, Charles January 2015 (has links)
The lunar space environment is shaped by the interaction between the Moon and the solar wind. In the present thesis, we investigate two aspects of this interaction, namely the interaction between solar wind protons and lunar crustal magnetic anomalies, and the interaction between solar wind protons and lunar regolith. We use particle sensors that were carried onboard the Chandrayaan-1 lunar orbiter to analyze solar wind protons that reflect from the Moon, including protons that capture an electron from the lunar regolith and reflect as energetic neutral atoms of hydrogen. We also employ computer simulations and use a hybrid plasma solver to expand on the results from the satellite measurements. The observations from Chandrayaan-1 reveal that the reflection of solar wind protons from magnetic anomalies is a common phenomenon on the Moon, occurring even at relatively small anomalies that have a lateral extent of less than 100 km. At the largest magnetic anomaly cluster (with a diameter of 1000 km), an average of ~10% of the incoming solar wind protons are reflected to space. Our computer simulations show that these reflected proton streams significantly modify the global lunar plasma environment. The reflected protons can enter the lunar wake and impact the lunar nightside surface. They can also reach far upstream of the Moon and disturb the solar wind flow. In the local environment at a 200 km-scale magnetic anomaly, our simulations show a heated and deflected plasma flow and the formation of regions with reduced or increased proton precipitation. We also observe solar wind protons reflected from the lunar regolith. These proton fluxes are generally lower than those from the magnetic anomalies. We find that the proton reflection efficiency from the regolith varies between ~0.01% and ~1%, in correlation with changes in the solar wind speed. We link this to a velocity dependent charge-exchange process occurring when the particles leave the lunar regolith. Further, we investigate how the properties of the reflected neutral hydrogen atoms depend on the solar wind temperature. We develop a model to describe this dependence, and use this model to study the plasma precipitation on the Moon when it is in the terrestrial magnetosheath. We then use the results from these and other studies, to model solar wind reflection from the surface of the planet Mercury. / Rymdmiljön runt månen formas av den växelverkan som sker mellan månen och solvinden. I den föreliggande avhandlingen undersöker vi två aspekter av denna växerverkan, nämligen växelverkan mellan solvindsprotoner och magnetiserade områden i månskorpan, och växelverkan mellan solvindsprotoner och månens ytdamm. Vi använder oss av partikelsensorer på månsatelliten Chandrayaan-1 för att analysera solvindsprotoner som reflekteras från månen, även de protoner som fångar upp en elektron från ytan och reflekteras som neutrala väteatomer. Vi använder oss också av datorsimuleringar för att bygga vidare på de uppmätta resultaten. Observationerna från Chandrayaan-1 visar att reflektion av solvindsprotoner från magnetiserade områden är ett vanligt förekommande fenomen på månen, som inträffar även vid magnetiseringar som är utbredda över mindre än 100 km. Vid det största magnetiserade området på månen (1000 km i diameter), reflekteras i genomsnitt ~10% av de infallande solvindsprotonerna. Våra datorsimuleringar visar att dessa protonflöden har globala effekter på månens plasmamiljö. De reflekterade protonerna kan nå månens nattsida. De kan också nå långt uppströms om månen och störa solvindsflödet. I den lokala plasmamiljön vid ett magnetiserat område av storleken 200 km visar våra simuleringar ett förändrat solvindsflöde, där det skapas områden som delvis skyddas från solvinden, likväl som områden som utsätts för mer solvind. Vi observerar även solvindsprotoner som reflekterats från ytdammet på månen. Dessa protonflöden är lägre än de från de magnetiska fälten. Reflektionen från ytan varierar mellan ~0.01% och 1% av solvindsflödet, i samband med förändringar i solvindshastigheten. Vi förklarar detta med att partiklarnas laddning bestäms av den hastighet de har när de lämnar måndammet. Vidare undersöker vi hur egenskaperna hos de reflekterade neutrala väteatomerna beror på solvindstemperaturen. Vi skapar en modell för att beskriva sambandet och använder sedan denna modell för att studera hur solvinden faller in mot månens yta när den befinner sig i jordens magnetoskikt, där jordens magnetfält orsakar en upphettning av solvindsflödet. Resultaten från dessa och andra studier använder vi sedan för att modellera solvindsreflektion från planeten Merkurius yta, för jämförelse med framtida observationer.
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A girl, a vampire and a werewolf : an audience ethnography of romance and gender representations in the films Twilight (2008) and New moon (2009)15 July 2015 (has links)
M.A (Audiovisual Communication) / In 2008 a film about a Gothic Romance between a teenage girl and a vampire became a pop culture phenomenon (Edwards, 2009:26). The ‘chick flick’ or ‘women’s film’ genre was suddenly in the spotlight at the box office as droves of female spectators of all ages were entranced by the neo-Gothic fantasy-Romance entitled Twilight (2008) (Em & Lo, 2009; Parekh, 2009:16; Puente, 2009:1; Ryan, 2008). More than 75% of the audience members were female with 55% being under 25 years (Ryan, 2008). Despite Twilight’s (2008) soaring status as a pop-culture phenomenon, much debate has ensued emphasizing the problematic representations and thematic elements that surround the gender roles and relations depicted in the film. As Lezra (2009:1) argues: “The cultural and social values…are so regressive that they would make people in Victorian London stand up and angrily defend the rights of women and minorities”. Twilight (2008) has been criticized for perpetuating traditional, oppressive, patriarchal values and glorifying a female character who has been termed “a feminist’s nightmare” (Czech, 2009) and “a 1950s-robot housewife” (Gassley, 2009). In 2009 the second instalment of the Twilight Saga: New Moon (2009) was released which had far more success than Twilight (2008) at the box office, as well as attracting a slightly older demographic (Gray, 2009a:1; Gray 2009b:1; Puente, 2009:1; Seltzer, 2009:1). The thematic conventions surrounding heterosexual relationships depicted in New Moon (2009) make the film particularly interesting. The film shifts focus from the relationship between Bella and her vampire love-interest Edward, as seen in Twilight (2008), to the relationship between Bella and her best friend Jacob, a werewolf. This relationship has been praised as the ‘ideal’ heterosexual relationship and Jacob, the ‘ideal’ partner: “Edward is not the ideal boyfriend-lover. In fact, Jacob is…Edward will only lead to black eyes, rape, torture, and possibly even death” (Housel, 2009a:188). Thus the representation of heterosexual relationships and gender roles within those relationships is brought into question in New Moon (2009). What makes the situation more complex is that despite these criticisms, so many women of multiple age groups are fans of the films. While there are many elements of the film which may contribute to this mass interest, such as fascination with the ‘undead’, or film being a temporary escape for spectators in times of economic instability and uncertainty (Olson, 1995:16), the appeal of this neo-gothic romance for women in particular needs to be examined more closely: “What did it mean that millions iv of girls were fantasizing about men who could barely repress the desire to kill them? In 2008?” (Mann, 2009:132). By integrating genre analysis and audience ethnography, this study explores the representations of gender roles and heterosexual romance in the films Twilight (2008) and New Moon (2009) and the perception of these representations by selected, female South African viewers. It further aims to situate the films within the sociocultural context in which it emerged and thus uses postfeminism as a theoretical framework.
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Diversidade da assembléia de morcegos (Quiropteros, Mammalia) em fragmentos de cerrado, no Parque Estadual de Vassununga e Estação Ecológica de Jataí, SP / Diversity of the bat assembly (Chiropters, Mammalia) of two cerrado fragments, Vassununga State Park and Jataí Ecological Station. (São Paulo, Brasil).Melo, Vivian Angelica Pinzon 28 August 2013 (has links)
A resposta da fauna à fragmentação e perda de hábitat pode variar amplamente segundo os requerimentos ecológicos, a configuração da paisagem, a conectividade e as pressões antrópicas. Os morcegos são bons candidatos para trabalhar os efeitos da fragmentação na fauna mas, mesmo assim, existem poucos estudos a respeito da diversidade dos morcegos frugívoros e sua dieta em áreas de cerrado do estado de São Paulo e nas demais áreas de cerrado do país, tendo em conta que este bioma vem sofrendo processos de mudança muito rápidos nas últimas décadas. Assim, vimos a importância de incorporar este grupo de fauna nos estudos que tem sido desenvolvidos na região. Durante 48 dias de coleta ao longo de um ano (2012), procurou-se inventariar a quiropterofauna de dois fragmentos de Cerrado correspondentes à Estação Ecológica de Jataí e ao Cerrado Pé-do-Gigante, nos municípios de Luiz Antônio e Santa Rita do Passa Quatro, localizados ao noroeste do Estado de São Paulo, sendo amostradas fisionomias diferentes: cerradão, cerrado sensu stricto, cerrado adensado e cerrado em estado de regeneração. Foram realizadas duas coletas mensais, de 4 horas cada, iniciadas após o pôr do sol, totalizando 24 amostragens em cada unidade de conservação. Os morcegos foram coletados com redes de neblina situadas a 50 cm do solo, em trilhas preexistentes e em áreas abertas, e identificados em nível de espécie. Outros dados ecológicos, como frequência, dominância, riqueza, constância, horário de atividade, dieta, dispersão de sementes através das fezes dos indivíduos capturados e a influência da luminosidade lunar foram analisados. Foram capturados e anilhados 195 indivíduos de 3 famílias e 7 subfamílias, pertencentes a 17 espécies diferentes, sendo 113 na estação chuvosa e 82 na estação seca. Na E.E. Jataí foram capturados 118 indivíduos de 15 espécies e, no Cerrado Pé-do-Gigante, 77 indivíduos, de 13 espécies, com um esforço amostral de de 31680 m². O índice de Shannon-Wiener apresentou uma diferencia sutil entre a diversidade de espécies em ambas as unidades de Conservação, constatada também pelo alto índice de similaridade de Sorensen (0,75). Obtiveram-se 5 recapturas, uma delas confirmando o fluxo entre unidades de conservação. As espécies dominantes foram: Artibeus lituratus, Anoura caudifer, Sturnira lilium, Glossophaga soricina e Carollia perspicillata. Com relação à dispersão de sementes, obtiveram-se 39 amostras de fezes, das quais 11 continham sementes que posteriormente foram germinadas em laboratório, obtendo-se assim 9 espécies de plantas petencentes a 4 gêneros, potencialmente dispersadas pela quiropterofauna local / The response of wildlife to fragmentation and habitat loss may vary widely according to the ecological requirements, landscape configuration, connectivity among landscape units, and anthropogenic pressures. Bats are ideal species to study fragmentation effects on wildlife, however, studies on the diversity of frugivore bats and their diet in savanna biomes are scarce, despite the intense changes linked to human pressures this biome has been recently submitted to. Therefore, we considered relevant to incorporate the evaluation of the regional bat assembly to fauna studies in Cerrado areas of São Paulo state. During a period of 48 days, representative of both rainy and dry seasons of 2012, we surveyed chiropterofauna in two Cerrado fragments, in the northwestern Sao Paulo state: Jataí Ecological Station (Luiz Antônio municipality) and Cerrado Pé-do-Gigante (Santa Rita de Passa-Quatro municipality). These units show different physiognomies: cerradão, cerrado sensu stricto, dense cerrado and cerrado in regeneration. The surveys were carried out under two nights per month in each conservation area. Bats were collected using mist nets located 50 cm above ground in existing trails in open areas. A total of 195 individuals belonging to 3 families, 7 subfamilies and 17 species were captured and ringed: 113 of these during the rainy season and the remaining 82 during dry season. In E.E. Jataí we registered 118 individuals belonging to 15 species, and in Cerrado Pé-do-Gigante, 77 individuals from 13 species (31680 m² of mist net in the two fragments of Cerrado). Most of the individuals recorded during the study belong to 5 species: Artibeuslituratus, Anoura caudifer, Sturnira Lilium, Glossophaga soricina and Carollia perspicillata. In relation to seed dispersion, 39 fecal samples were obtained, of these, 11 contained seeds that later were germinated in laboratory, obtaining nine species of plants of 4 geners potentiality dispersed by the local bats
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Laughing in Space: Robert Heinlein's The Moon is a Harsh Mistress and Towards a New Humor FrameworkUnknown Date (has links)
Humor’s effect on the audience’s relationship to the object, or speaker, of humor
has often been neglected, and creating a framework by which scholars can examine how
humor works to alter the relationship between audience and other fills this gap.
Additionally, the definition of science fiction relies on the existence of a cognitively
estranging other and under this definition, humor has not been thoroughly studied. This
thesis attempts to explain how humor affects audiences cognitively, utilizing Hegel’s
theory of self and other, and then applies this theoretical explanation to the field of
science fiction and examines its effects. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection
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Rendimento, qualidade e conservação pós-colheita de cenoura (Daucus carota L.), sob cultivo biodinâmico, em função dos ritmos lunares /Jovchelevich, Pedro, 1968- January 2007 (has links)
Orientador: Francisco Luiz Araújo Câmara / Banca: Antônio Ismael Inácio Cardoso / Banca: Roberto Boczko / Resumo: O presente trabalho teve como objetivo avaliar a influência dos diversos ritmos da Lua (sinódico, sideral, anomalístico, tropical e draconiano) sobre o rendimento, a qualidade e a conservação pós-colheita de cenoura, quando semeada em diferentes datas, sob as mesmas condições de manejo, em uma propriedade familiar com manejo biodinâmico no município de Botucatu-SP. O delineamento experimental utilizado foi o de blocos ao acaso com 31 tratamentos em 2005, e 14 tratamentos em 2006. A diferença entre tratamentos foi a data de semeadura, que variou de 5 de maio a 4 de junho em 2005, e de 25 de abril a 25 de maio em 2006, sempre entre 13 e 15hs. A colheita foi feita 82 dias depois de cada semeadura, equivalente a três ciclos da lua sideral, e no ponto que o consumidor de produtos orgânicos e biodinâmicos valoriza, segundo experiência do produtor. Para retirar o efeito da tendência dos dados na avaliação dos tratamentos, foi utilizada a metodologia de avaliação estatística do cálculo do Índice Estacional (IE). Foram avaliadas as seguintes características: massa fresca de raízes e folhas, massa seca, diâmetro, comprimento, teor de nitrogênio, fósforo e boro das raízes e perecibilidade das raízes com 30, 60 e 90 dias póscolheita. Nos dois períodos avaliados, a massa seca de raízes foi a única que, no contraste entre médias, apresentou diferença significativa nos ritmos sinódico tradicional e sinódico caboclo. No ritmo sinódico tradicional, a fase nova foi superior às fases crescente e cheia. No sinódico caboclo, a fase cheia foi inferior às demais. No contraste entre médias, o ritmo sinódico foi o que mais apresentou resultados significativos, e em menor proporção, os ritmos anomalístico, draconiano e sideral; O ritmo tropical (ascendente X descendente) e teor de nitrogênio não apresentaram resultados significativos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The purpose of this work was to evaluate the influence of moon rhythms (synodic, sidereal, anomalistic, tropical and draconic) on yield, quality and postharvest storage of Daucus carota L. roots under biodynamic management sowed in different dates. The experiment was carried out over a two period on a biodynamic farm, in Botucatu, São Paulo State, Brazil. Rhythms were tested observing the effects of seeding at different planting dates. The experiment was performed with four randomized blocks and 31 treatments (different dates) in 2005 and fourteen treatments in 2006. The harvest occurred 82 days after the sowing, when carrot roots show the most desirable aspect for the organic and biodynamic consumers. The magnitudes of effects associated with planting at a specific lunar position were measured by the deviations from the trend curve. The following characteristics were evaluated: fresh mass of roots and leaves, dry mass, diameter, length, nitrogen, phosphorus and boron content of the roots and perishability of the roots at 30, 60 and 90 days post-harvest. Dry mass was the only one that in the contrast between averages showed significant results in the two periods of the experiment. Result was that the synodic new phase was superior to the first quarter, and full phases and in the "caboclo" synodic rhythm, the full phase was inferior to the other. It was clear that the synodic "caboclo" rhythm had the most significant influence followed by the traditional synodic one. The draconic, sideral and anomalistic had less influence and the tropical rhythm had no influence at all considering studied aspects. Nitrogen and tropical rhythm did not present any lunar influence. The two evaluated periods are still not conclusive related... (Complete abstract click electronic access below) / Mestre
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Estudo e simulação do déficit de raios cósmicos devido à lua no experimento MINOS / Study and simulation of the cosmic rays deficit due to the moon in the minos experimentMedeiros, Michelle Mesquita de 01 September 2011 (has links)
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Previous issue date: 2011-09-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Celestial objects / Objetos celestes como a Lua e o Sol bloqueiam os raios cósmicos que vem de suas direções para a Terra, produzindo um défcit chamado de sombra. A medida deste défcit possibilita a determinação da resolução angular e do alinhamento de detectores de raios cósmicos, o estudo dos campos magnéticos terrestre, solar e interplanetário e a determinação da razão antipróton/próton na escala de energia TeV. Vários experimentos já observaram a sombra de raios cósmicos da Lua e/ou do Sol com o objetivo de calibrar seus detectores. Descrevemos neste trabalho o experimento MINOS e seus resultados da sombra da Lua e do Sol. Simulamos a sombra da Lua levando em conta seu movimento no céu e, para tanto, de nimos e testamos métodos de simulação e diferentes composições para os raios cósmicos. Também avaliamos várias proporções para antiprótons no fluxo de raios cósmicos a m de comparar com os resultados
do experimento MINOS e conjecturar uma possível razão p=p para os dados observados. Ambos os métodos que de nimos, método do dé cit e da fonte de raios cósmicos, permitiram
uma análise qualitativa da sombra. No entanto, só foi possível realizar uma análise quantitativa na simulação tendo a Lua como um défcit. Dessa forma, adotamos este método para as
simulações subsequentes. Notamos algumas diferenças para as sombras obtidas usando próton e núcleo de hélio como partículas primárias de raios cósmicos. Todavia, a sombra encontrada combinando prótons (90%) e núcleos de hélio (10%) foi semelhante à sombra obtida apenas para prótons. Na simulação incluindo o movimento da Lua, avaliamos os efeitos do campo geomagnético na partícula primária, desde a Lua até a atmosfera terrestre, e nos múons (partícula
secundária) desde sua produção até o nível do mar. Como esperado, obtivemos uma sombra da Lua mais similar com os resultados do experimento MINOS ao incluir a de exão tanto das partículas primárias dos raios cósmicos quanto das partículas do chuveiro do que considerando apenas o desvio destas últimas. Nossa simulação foi capaz de reproduzir a sombra provocada pela Lua com a localização do maior dé cit comparável àquela encontrada pelo experimento MINOS. Entretanto, ainda acrescentamos núcleos de hélio e antiprótons na simulação incluindo o movimento da Lua com o objetivo de melhorar o resultado. Obtivemos um défcit localizado o mais próximo possível do obtido pelo experimento MINOS usando a proporção p=p = 0;45. Tal resultado deve ser melhor estudado e a simulação aprimorada para que se determine esta razão entre antiprótons e prótons com a precisão adequada.
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Regolith Properties of Mercury Derived from Observations and ModellingWarell, Johan January 2003 (has links)
<p>The properties of Mercury's regolith have been investigated at optical and near-infrared wavelengths with high-resolution imaging, photometric, and spectroscopic observations with the Swedish Vacuum Solar Telescope and the Nordic Optical Telescope. </p><p>A new global optical map at a spatial resolution of 200 km shows that the well known (from Mariner 10) and poorly known hemispheres are indistinguishable with respect to the distribution, number density, and morphological parameters of bright albedo features. This indicates a globally uniform recent (<3 Gyr) geologic evolution, a compositionally very homogeneous surface and the absence of a lunar-like mare–terrae albedo dichotomy.</p><p>It is found that the spectrum of Mercury is linear, strongly sloped, lacks detectable absorption features and displays a unique relation between the continuum slope and photometric geometry. Mercury has a photometrically smoother surface than the average near-side Moon, and is 10–15% fainter and 50% more back scattering in the V-band. Unlike the case for the Moon, the average single-particle backscattering anisotropy increases with wavelength.</p><p>Intimate regolith mixing models are used to determine a probable surface composition of predominantly Ca-rich labradorite plagioclase feldspar with minor low-iron enstatitic orthopyroxene, and rule out high-iron pyroxenes or olivines as other than insignificant constituents. Abundances of FeO ~1.2 wt%, TiO<sub>2</sub> ~0 wt%, and submicroscopic metallic iron ~0.1–0.3 wt% are found for the average surface. This implies an optically active grain size of 15–30 μm that is a factor of two smaller than for the Moon.</p><p>A numerical integration study shows that hermeocentric orbits with semi-major axes <30 mercurian radii for elliptic retrograde, and circular prograde, object are stable for durations in excess of 4.5 Myr. The weak gravitational scattering effect of Mercury indicates that re-impacting particles may have been important for the early evolution of its crust.</p>
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