An astrometric facility for planetary detection on the space station

An Astrometric Telescope Facility (ATF) for planetary detection is being studied as a potential space station initial operating capability payload. The primary science objective of this mission is the detection and study of planetary systems around other stars. In addition, the facility will be capable of other astrometric measurements such as stellar motions of other galaxies and highly precise direct measurement of stellar distance within the Milky Way Galaxy. The results of a recently completed ATF preliminary systems definition study are summarized. Results of this study indicate that the preliminary concept for the facility is fully capable of meeting the science objective without the development of any new technologies. A simple straightforward operations approach was developed for the ATF. A real-time facility control is not normally required, but does maintain a near real-time ground monitoring capability for the facility and science data stream on a full-time basis. Facility observational sequences are normally loaded once a week. In addition, the preliminary system is designed to be fail-safe and single-fault tolerant. Routine interactions by the space station crew with the ATF will not be necessary, but onboard controls are provided for crew override as required for emergencies and maintenance

Feasibility of mining lunar resources for earth use: Circa 2000 AD. Volume 1: Summary

The feasibility of obtaining lunar minerals for terrestrial uses is examined. Preliminary results gave indications that it will not be economically feasible to mine, refine, and transport lunar materials to Earth for consumption. A broad systems approach was used to analyze the problem. It was determined that even though the procedure was not economically advisable, the concept for the operations is technically sound

Method for detecting coliform organisms

A method and apparatus are disclosed for determining the concentration of coliform bacteria in a sample. The sample containing the coliform bacteria is cultured in a liquid growth medium. The cultured bacteria produce hydrogen and the hydrogen is vented to a second cell containing a buffer solution in which the hydrogen dissolves. By measuring the potential change in the buffer solution caused by the hydrogen, as a function of time, the initial concentration of bacteria in the sample is determined. Alternatively, the potential change in the buffer solution can be compared with the potential change in the liquid growth medium to verify that the potential change in the liquid growth medium is produced primarily by the hydrogen gas produced by the coliform bacteria

Anomalous shell effect in the transition from a circular to a triangular billiard

We apply periodic orbit theory to a two-dimensional non-integrable billiard system whose boundary is varied smoothly from a circular to an equilateral triangular shape. Although the classical dynamics becomes chaotic with increasing triangular deformation, it exhibits an astonishingly pronounced shell effect on its way through the shape transition. A semiclassical analysis reveals that this shell effect emerges from a codimension-two bifurcation of the triangular periodic orbit. Gutzwiller's semiclassical trace formula, using a global uniform approximation for the bifurcation of the triangular orbit and including the contributions of the other isolated orbits, describes very well the coarse-grained quantum-mechanical level density of this system. We also discuss the role of discrete symmetry for the large shell effect obtained here.Comment: 14 pages REVTeX4, 16 figures, version to appear in Phys. Rev. E. Qualities of some figures are lowered to reduce their sizes. Original figures are available at http://www.phys.nitech.ac.jp/~arita/papers/tricirc

A consideration of the effects of the slip displacement on fretting fatigue behaviour

Published versio

Performance considerations for the astrometric telescope facility on the phase 1 space station

The Astrometric Telescope Facility (ATF) is an optical telescope facility of extreme astrometric precision whose principle scientific purpose is the detection and study of planetary systems about nearby stars. With the recent change in the space station program to two phases, the suitability of initial operations from the phase 1 station need to be evaluated. This paper presents the results of such an evaluation for the Astrometric Telescope Facility

Nonlinear Evolution of Very Small Scale Cosmological Baryon Perturbations at Recombination

The evolution of baryon density perturbations on very small scales is investigated. In particular, the nonlinear growth induced by the radiation drag force from the shear velocity field on larger scales during the recombination epoch, which is originally proposed by Shaviv in 1998, is studied in detail. It is found that inclusion of the diffusion term which Shaviv neglected in his analysis results in rather mild growth whose growth rate is $\ll 100$ instead of enormous amplification $\sim 10^4$ of Shaviv's original claim since the diffusion suppresses the growth. The growth factor strongly depends on the amplitude of the large scale velocity field. The nonlinear growth mechanism is applied to density perturbations of general adiabatic cold dark matter (CDM) models. In these models, it has been found in the previous works that the baryon density perturbations are not completely erased by diffusion damping if there exists gravitational potential of CDM. With employing the perturbed rate equation which is derived in this paper, the nonlinear evolution of baryon density perturbations is investigated. It is found that: (1) The nonlinear growth is larger for smaller scales. This mechanism only affects the perturbations whose scales are smaller than $\sim 10^2M_\odot$, which are coincident with the stellar scales. (2) The maximum growth factors of baryon density fluctuations for various COBE normalized CDM models are typically less than factor 10 for $3-\sigma$ large scale velocity peaks. (3) The growth factor depends on $\Omega_{\rm b}$.Comment: 24 pages, 9 figures, submitted to Ap

Study, Design and Test of a LENZ-type Wind Turbine

The current concern about reducing dependence on fossil fuels and issues about environmental conditions have guided the survey for renewable energies around the world. The present work was focused in the study, design, construction and laboratorial tests of a small-size vertical-axis wind turbine (VAWT) of Lenz-type. The wind turbine was chosen based on criteria of operation in turbulent winds and mainly due to low-cost of fabrication and possibility to use it in farms. The study was carried out in the description of wind resources in a specific area from countryside of Brazil. The Lenz turbine was designed, drawn, built and later tested in a low-speed wind tunnel. Experimental data were gathered to describe the characteristics of the prototype and to guide for further modifications to improve wind power efficiency