A method for representing the thermodynamic and thermophysical functions in simulation of powerplant processes

A method for representing thermodynamic and thermophysical functions is presented; the functions make it possible to simulate thermal and gasodynamic processes in powerplants that use different individual substances or their mixtures as a working fluid. The method also involves consideration of real gas properties.     

Calculation of tractive nozzle characteristics with altitude compensation

The numerical calculations of flows in conical and contoured nozzles with slots in the supersonic part that operate under overexpansion conditions are presented. The calculations were made with the aid of the authors’ algorithm and program of simulating turbulent two-dimensional (axisymmetric) flows of a viscous heat-conducting gas. The results of computational investigations of tractive slot nozzle characteristics and the amount of combustion product leakage from an annular slot depending on the flight altitude are given. It is shown that the flight altitude at which the gas flow through the annular slot is “chocked” depends on its size and location in the supersonic nozzle part.     

HIRDES – The High-Resolution Double-Echelle Spectrograph for the World Space Observatory Ultraviolet (WSO/UV)

The World Space Observatory Ultraviolet (WSO/UV) is a multi-national project grown out of the needs of the astronomical community to have future access to the UV range. WSO/UV consists of a single UV telescope with a primary mirror of 1.7 m diameter feeding the UV spectrometer and UV imagers. The spectrometer comprises three different spectrographs, two high-resolution echelle spectrographs (the High-Resolution Double-Echelle Spectrograph, HIRDES) and a low-dispersion long-slit instrument. Within HIRDES the 102–310 nm spectral band is split to feed two echelle spectrographs covering the UV range 174–310 nm and the vacuum-UV range 102–176 nm with high spectral resolution (R > 50,000). The technical concept is based on the heritage of two previous ORFEUS SPAS missions. The phase-B1 development activities are described in this paper considering performance aspects, design drivers, related trade-offs (mechanical concepts, material selection etc.) and a critical functional and environmental test verification approach. The current state of other WSO/UV scientific instruments (imagers) is also described.     

Solar signals in the minimum extreme temperature records in the southern region of the Gulf of Mexico

Minimum extreme temperature series from several meteorological stations of the Gulf of Mexico are spectrally analyzed using the Maximum Entropy Method.We obtained significant periodicities similar to those found in meteorological and solar activity phenomena. This indicates that probably the solar activity signals are present in the minimum extreme temperature records of this Mexican region.     

High resolution science with high redshift galaxies

We summarize the high-resolution science that has been done on high redshift galaxies with Adaptive Optics (AO) on the world’s largest ground-based facilities and with the Hubble Space Telescope (HST). These facilities complement each other. Ground-based AO provides better light gathering power and in principle better resolution than HST, giving it the edge in high spatial resolution imaging and high resolution spectroscopy. HST produces higher quality, more stable PSF’s over larger field-of-views in a much darker sky-background than ground-based AO, and yields deeper wide-field images and low-resolution spectra than the ground. Faint galaxies have steadily decreasing sizes at fainter fluxes and higher redshifts, reflecting the hierarchical formation of galaxies over cosmic time. HST has imaged this process in great structural detail to z  6, and ground-based AO and spectroscopy has provided measurements of their masses and other physical properties with cosmic time. Last, we review how the 6.5 m James Webb Space Telescope (JWST) will measure First Light, reionization, and galaxy assembly in the near–mid-IR after 2013.     

Lower-mesospheric inversion layers over brazilian equatorial region using TIMED/SABER temperature profiles

Lower-mesospheric inversion layers (MILs) were studied using the temperature profiles observed by TIMED/SABER over Cariri (7.5°S, 36.5°W), Brazil, in 2005. A total 175 MILs were identified with the maximum occurrence in April and October and the minimum in January and July. The lower MIL is located in a height region from 70 to 90 km, with the peak at around 83 ± 4 km with the temperature of 205 ± 5 K, and the thickness of 4–10 km. The results show large amplitudes of MILs during equinoxes and minimum in solstices, with a clear semiannual variation. A general feature of lower MIL in monthly mean profile was observed twice a year, one from February to May, and the other from August to October with a downward shift of the top level. These results suggest that formation and long persistence of MIL is an important factor to investigate propagation of atmospheric gravity waves in the mesosphere-lower thermosphere (MLT) region.     

Relation between galactic and solar cosmic radiation at aviation altitude

Cosmic radiation bombards us at high altitude with ionizing particles; the radiation has a galactic component, which is normally dominant, and a component of solar origin. Cosmic ray particles are the primary source of ionization in the atmosphere above 1 km; below 1 km radon is a dominant source of ionization in many areas.     

Discovery of a new chert-permineralized microbiota in the Proterozoic Buxa Formation of the Ranjit window, Sikkim, northeast India, and its astrobiological implications

For the foreseeable future, the search for evidence of past life in rocks acquired from other planets will be constrained by the amount of sample available and by the fidelity of preservation of any fossils present. What amount of rock is needed to establish the existence of past life? To address this question, we studied a minute amount of rock collected from cherty dolomites of the Proterozoic Buxa Formation in the metamorphically altered tectonically active northeastern Himalaya. In particular, we investigated 2 small petrographic thin sections-one from each of 2 bedded chert horizons exposed in the Ranjit River stratigraphic section northwest of Rishi, Sikkim, India-that together comprise an area of approximately 5 cm(2) (about the size of a US postage stamp) and have a total rock weight of approximately 0.1 g. Optical microscopy, confocal laser scanning microscopy, and Raman spectroscopy and imagery demonstrate that each of the thin sections contains a rich assemblage of 3-dimensionally permineralized organic-walled microfossils. This study, the first report of Proterozoic microfossils in units of the Ranjit tectonic window, demonstrates that firm evidence of early life can be adduced from even a minuscule amount of fossil-bearing ancient rock.     

Fluorescence microscopy as a tool for in situ life detection

The identification of extant and, in some cases, extinct bacterial life is most convincingly and efficiently performed with modern high-resolution microscopy. Epifluorescence microscopy of microbial autofluorescence or in conjunction with fluorescent dyes is among the most useful of these techniques. We explored fluorescent labeling and imaging of bacteria in rock and soil in the context of in situ life detection for planetary exploration. The goals were two-fold: to target non-Earth-centric biosignatures with the greatest possible sensitivity and to develop labeling procedures amenable to robotic implementation with technologies that are currently space qualified. A wide panel of commercially available dyes that target specific biosignature molecules was screened, and those with desirable properties (i.e., minimal binding to minerals, strong autofluorescence contrast, no need for wash steps) were identified. We also explored the potential of semiconductor quantum dots (QDs) as bacterial and space probes. A specific instrument for space implementation is suggested and discussed.     

Some ecological mechanisms to generate habitability in planetary subsurface areas by chemolithotrophic communities: the Río Tinto subsurface ecosystem as a model system

Chemolithotrophic communities that colonize subsurface habitats have great relevance for the astrobiological exploration of our Solar System. We hypothesize that the chemical and thermal stabilization of an environment through microbial activity could make a given planetary region habitable. The MARTE project ground-truth drilling campaigns that sampled cryptic subsurface microbial communities in the basement of the Río Tinto headwaters have shown that acidic surficial habitats are the result of the microbial oxidation of pyritic ores. The oxidation process is exothermic and releases heat under both aerobic and anaerobic conditions. These microbial communities can maintain the subsurface habitat temperature through storage heat if the subsurface temperature does not exceed their maximum growth temperature. In the acidic solutions of the Río Tinto, ferric iron acts as an effective buffer for controlling water pH. Under anaerobic conditions, ferric iron is the oxidant used by microbes to decompose pyrite through the production of sulfate, ferrous iron, and protons. The integration between the physical and chemical processes mediated by microorganisms with those driven by the local geology and hydrology have led us to hypothesize that thermal and chemical regulation mechanisms exist in this environment and that these homeostatic mechanisms could play an essential role in creating habitable areas for other types of microorganisms. Therefore, searching for the physicochemical expression of extinct and extant homeostatic mechanisms through physical and chemical anomalies in the Mars crust (i.e., local thermal gradient or high concentration of unusual products such as ferric sulfates precipitated out from acidic solutions produced by hypothetical microbial communities) could be a first step in the search for biological traces of a putative extant or extinct Mars biosphere.