Optimal Trajectories for Near-Earth-Objects Using Solar Electric Propulsion (SEP) and Gravity Assisted Maneuver

The future interplanetary missions will probably use the conventional chemical rockets to leave the sphere of influence of the Earth, and solar electric propulsion (SEP) to accomplish the other maneuvers of the mission. In this work the optimization of interplanetary missions using solar electric propulsion and Gravity Assisted Maneuver to reduce the costs of the mission, is considered. The high specific impulse of electric propulsion makes a Gravity Assisted Maneuver 1 year after departure convenient. Missions for several Near Earth Asteroids will be considered. The analysis suggests criteria for the definition of initial solutions demanded for the process of optimization of trajectories. Trajectories for the asteroid 2002TC70 are analyzed. Direct trajectories, trajectories with 1 gravity assisted from the Earth and with 2 gravity assisted from the Earth and either Mars are present. An indirect optimization method will be used in the simulations

Superscars in the LiNC=LiCN isomerization reaction

We demonstrate the existence of superscarring in the LiNC=LiCN isomerization reaction described by a realistic potential interaction in the range of readily attainable experimental energies. This phenomenon arises as the effect of two periodic orbits appearing "out of the blue"in a saddle--node bifurcation taking place in the dynamics of the system. Potential practical consequences of this superlocalization in the corresponding wave functions are also considered.Comment: 6 pages, 5 figures. to appear in EP

Periodic orbit bifurcations and scattering time delay fluctuations

We study fluctuations of the Wigner time delay for open (scattering) systems which exhibit mixed dynamics in the classical limit. It is shown that in the semiclassical limit the time delay fluctuations have a distribution that differs markedly from those which describe fully chaotic (or strongly disordered) systems: their moments have a power law dependence on a semiclassical parameter, with exponents that are rational fractions. These exponents are obtained from bifurcating periodic orbits trapped in the system. They are universal in situations where sufficiently long orbits contribute. We illustrate the influence of bifurcations on the time delay numerically using an open quantum map.Comment: 9 pages, 3 figures, contribution to QMC200

Potencial de uso de métricas de paisagem para relacionar a dinâmica de uso da terra com a qualidade da água: estudo de caso na região serrana do Estado do Rio de Janeiro.

A configuração de uma paisagem está relacionada à dinâmica do uso e cobertura da terra na qual ela se insere. Este fato afeta diretamente a sua estrutura e confere padrões espaciais aos fragmentos florestais, bem como aos usos predominantes da terra de uma determinada região. Essa configuração espacial reflete tanto nos processos naturais como a qualidade da água, quanto nos aspectos socioeconômicos associados. Por isso, faz-se necessário o entendimento dessa distribuição espacial; o que pode ser obtido a partir do cálculo de métricas de paisagem. No presente trabalho foram analisadas 16 métricas de paisagem em uma bacia de drenagem na região montanhosa do Rio de Janeiro, denominada Pito Aceso - afluente do Rio Grande, que por sua vez é afluente do Rio Paraíba do Sul. Posteriormente aos cálculos das métricas, foi realizada uma análise por componentes principais onde foi possível observar as métricas que se mostraram mais eficientes para evidenciar a estrutura da paisagem em análise. Como estudos da qualidade da água também foram realizados na bacia, a próxima etapa do trabalho será associar esses resultados aos resultados de qualidade da água, de forma a demonstrar a potencialidade do uso dessas análises para subsidiar o planejamento sustentável das paisagens bem como dos recursos hídricos

Evaluating geoscan AMSS MK-II for gold exploration in the Fazenda Maria Preta District, Rio Itapicuru greenstone belt, Bahia State, Brazil

The Rio Itapicuru Greenstone Belt (RIGB), located in north-eastern Brazil, is an important gold producing region. It hosts two important mining districts, the Fazenda Brasileiro and the Fazenda Maria Preta, owned by Companhia Vale do Rio Doce (CVRD), plus a number of gold occurrences, all associated with hydrothermal alteration along shear zones. In 1992, Geoscan multispectral scanner data were acquired for mineral exploration purposes over more than 7,500 km² in this greenstone belt. Geoscan AMSS is a 24-band airborne scanner, with 5 meter spatial resolution. Standard image processing techniques, applied immediately after data acquisition, defined some spectral anomalies, particularly due to silicification and oxidation, which could be due either to hydrothermal alteration or to weathering processes. We have reprocessed the Geoscan data over a portion of the RIGB in order to define possible anomalies due to hydrothermal alteration minerals, using the feature-oriented principal component selection (FPCS) technique, modified for use with Geoscan data. Laboratory reflectance spectra of residual soils were acquired to establish superficial expression of hydrothermal minerals that occur in sub-surface and to guide image processing and interpretation. This led to the production of "mineral component" images, in which the spatial distribution of some minerals are shown. Results of the spectral analysis of soil samples showed that goethite may be used as a surface indicator of hydrothermal alteration and that it is not possible to differentiate the alteration zones from surrounding rocks based on the hydroxyl or carbonate spectral features.O Greenstone Belt do Rio Itapicuru (RIGB), localizado no nordeste do Brasil, é uma importante região produtora de ouro no país. Ele contém dois importantes distritos mineiros, o da Fazenda Brasileiro e Fazenda Maria Preta, pertencentes à Companhia Vale do Rio Doce (CVRD), além de diversas outras ocorrências auríferas, todas elas associadas a processo de alteração hidrotermal ao longo de zonas de cisalhamento. Em 1992, imagens do sensor multiespectral Geoscan foram obtidas em mais de 7.500 km² do greenstone. O Geoscan AMSS Mk-II é um sensor aeroportado que cobre 24 bandas espectrais, com 5 metros de resolução espacial no caso deste levantamento. Técnicas padrão de processamento de imagens, aplicadas imediatamente após o levantamento, definiram uma série de anomalias espectrais, relacionadas a processos de silicifícação e oxidação, que podem tanto ser devidos a processos de alteração hidrotermal quanto intempéricos. Esses dados foram reprocessados para uma porção do RIGB na tentativa de se definir possíveis anomalias espectrais devidas a minerais de alteração hidrotermal, utilizando a técnica denominada feature-ohentated principal component selection (FPCS), modificada para uso com os dados Geoscan. Análises espectrais de laboratório foram realizadas em amostras de solos residuais e em rochas, no sentido de estabelecer a expressão superficial dos minerais de alteração hidrotermal que ocorrem em sub-superfície e orientar o processamento e a interpretação das imagens. Isso resultou na produção de imagens "componentes minerais", nas quais a distribuição espacial de alguns minerais de alteração é mostrada. Resultados da análise espectral de solos residuais mostraram que a goetita pode ser utilizada como um indicador superficial da presença de alteração hidrotermal e que não é possível diferenciar as zonas de alteração das rochas que as contém com base em feições espectrais de minerais contendo o ânion hidroxila ou carbonato

Fluorescence and Hybrid Detection Aperture of the Pierre Auger Observatory

The aperture of the Fluorescence Detector (FD) of the Pierre Auger Observatory is evaluated from simulated events using different detector configurations: mono, stereo, 3-FD and 4-FD. The trigger efficiency has been modeled using shower profiles with ground impacts in the field of view of a single telescope and studying the trigger response (at the different levels) by that telescope and by its neighbours. In addition, analysis cuts imposed by event reconstruction have been applied. The hybrid aperture is then derived for the Auger final extension. Taking into account the actual Surface Detector (SD) array configuration and its trigger response, the aperture is also calculated for a typical configuration of the present phase.Comment: contribution to the 29th International Cosmic Ray Conference, Pune, India, 3-10 August 200

Coal Quality Management Model For Dome Storage (DS-CQMM)

Coal quality (ash, sulphur, moisture, and heating value) is one of the fundamental concerns for both coal mines and power plants. In order to deliver uniform coal quality to the power plant, there is a need for realtime monitoring of coal quality from the mine to the coal stockpiles. The specific problem represents the process of stacking the coal inside an enclosed facility such as a dome. The objective of this research was to develop a custom-made and integrated coal quality management model for dome storage (DS-CQMM). The DS-CQMM merges existing technology in surface mines, such as coal analysers, together with automation technologies, information technologies (IT), and mathematical models. The DS-CQMM is organized into four major sections: Delay Time application, Stacker application, Reclaimer application, and Live Stockpile application. A sub-process called Volume Calculation is embedded in Stacker application, while an additional feature called Forecast tool is included in the Reclaimer application. The DS-CQMM model was developed for a surface coal mine in the southern USA

Impact of DM direct searches and the LHC analyses on branon phenomenology

Dark Matter direct detection experiments are able to exclude interesting parameter space regions of particle models which predict an important amount of thermal relics. We use recent data to constrain the branon model and to compute the region that is favored by CDMS measurements. Within this work, we also update present colliders constraints with new studies coming from the LHC. Despite the present low luminosity, it is remarkable that for heavy branons, CMS and ATLAS measurements are already more constraining than previous analyses performed with TEVATRON and LEP data.Comment: 17 pages, 2 figure

Fractal Weyl law behavior in an open, chaotic Hamiltonian system

We numerically show fractal Weyl law behavior in an open Hamiltonian system that is described by a smooth potential and which supports numerous above-barrier resonances. This behavior holds even relatively far away from the classical limit. The complex resonance wave functions are found to be localized on the fractal classical repeller.Comment: 4 pages, 3 figures. to appear in Phys Rev