A mechanical adapter for installing mission equipment on large space structures

A mechanical attachment adapter was designed, constructed, and tested. The adapter was was included in a simulation program that investigated techniques for assembling erectable structures under simulated zero-g conditions by pressure-suited subjects in a simulated EVA mode. The adapter was utilized as an interface attachment between a simulated equipment module and one node point of a tetrahedral structural cell. The mating performance of the adapter, a self-energized mechanism, was easily and quickly demonstrated and required little effort on the part of the test subjects

Restaurant Marquees: A Help or Hindrance\u27?

The marquee is one of the most common and cost-effective forms of advertising, but it can be a restaurant\u27s worst enemy. Here are some surprising facts about its use and misuse

Analytics of crystal growth in space

The variation of radial impurity distribution induced by surface tension driven flow increases as the zone length decreases in silicon crystals grown by floating zone melting. In combined buoyancy driven and surface tension driven convection at the gravity of earth, the buoyancy contribution becomes relatively smaller as the zone diameter decreases and eventually convection is dominated by the surface tension driven flow (in the case of silicon, for zones of less than about 0.8 cm in diameter). Preliminary calculations for sapphire suggest the presence of an oscillatory surface tension driven convection as a result of an unstable melt surface temperature that results when the zone is heated by a radiation heater

Pure multiplicative stochastic resonance of anti-tumor model with seasonal modulability

The effects of pure multiplicative noise on stochastic resonance in an anti-tumor system modulated by a seasonal external field are investigated by using theoretical analyses of the generalized potential and numerical simulations. For optimally selected values of the multiplicative noise intensity quasi-symmetry of two potential minima and stochastic resonance are observed. Theoretical results and numerical simulations are in good quantitative agreement.Comment: 5 pages, 5 figure

The temperature dependency of Wolf-Rayet-type mass loss: An exploratory study for winds launched by the hot iron bump

CONTEXT: The mass loss of He-burning stars, which are partially or completely stripped of their outer hydrogen envelope, is a catalyst of the cosmic matter cycle and decisive ingredient of massive star evolution. Yet, its theoretical fundament is only starting to emerge with major dependencies still to be uncovered. AIMS: A temperature or radius dependence is usually not included in descriptions for the mass loss of classical Wolf-Rayet (cWR) stars, despite being crucial for other hot star wind domains. We thus aim to determine whether such a dependency will also be necessary for a comprehensive description of mass loss in the cWR regime. METHODS: Sequences of dynamically consistent atmosphere models were calculated with the hydrodynamic branch of the PoWR code along the temperature domain, using different choices for luminosity, mass, and surface abundances. For the first time, we allowed nonmonotonic velocity fields when solving the equation of motion. The resulting velocity structures were then interpolated for the comoving-frame radiative transfer, ensuring that the main wind characteristics were preserved. RESULTS: We find a strong dependence of the mass-loss rate with the temperature of the critical/sonic point which mainly reflects the different radii and resulting gravitational accelerations. Moreover, we obtain a relation between the observed effective temperature and the transformed mass-loss rate which seems to be largely independent of the underlying stellar parameters. The relation shifts for different clumping factors in the outer wind. Below a characteristic value of -4.5, the slope of this relation changes and the winds become transparent for He II ionizing photons. CONCLUSIONS: The mass loss of cWR stars is a high-dimensional problem but also shows inherent scalings which can be used to obtain an approximation of the observed effective temperature. (...)Comment: 16 pages + 5 page appendix, 17+9 figures, 3+2 tables. Accepted for publication in A&

New strains obtained after UV treatment and protoplast fusion of native Trichoderma harzianum: their biocontrol activity on Pyrenochaeta lycopersici

Indexación: ScieloThe obtainment of 30 new strains from native Trichoderma harzianum after UV light irradiation (UV-A and UV-C), and of 82 strains resulted from protoplast fusion were accomplished. The new strains, initially selected for their growing rate under low temperature and high pH conditions, as well as for their innocuousness on tomato plants, were tested for in vitro inhibition of Pyrenochaeta lycopersici in dual cultures and due to secretion of volatile and diffusible metabolites. All the UV-A and UV-C selected candidate mutants were innocuous to tomato plants, but none of them showed improvement in their biocontrol activity on P. lycopersici. Th12A20.1 increased 1.3 and 1.9 fold the total fresh weight of Fortaleza tomato plants when compared to its parental strains Th12 and Th11, respectively. The selected candidate mutants obtained through protoplast fusion were also innocuous to tomato plants, but only ThF1-2 and ThF4-4 inhibited 1.3 fold (in dual cultures) and 5 fold (due to secretion of volatile metabolites) the growth of P. lycopersici, respectively, in relation to the mean inhibitory effect of both parents. Therefore, these candidate mutants could be included in experiments under field conditions