Electro-optic architecture for servicing sensors and actuators in advanced aircraft propulsion systems

A detailed design of a fiber optic propulsion control system, integrating favored sensors and electro-optics architecture is presented. Layouts, schematics, and sensor lists describe an advanced fighter engine system model. Components and attributes of candidate fiber optic sensors are identified, and evaluation criteria are used in a trade study resulting in favored sensors for each measurand. System architectural ground rules were applied to accomplish an electro-optics architecture for the favored sensors. A key result was a considerable reduction in signal conductors. Drawings, schematics, specifications, and printed circuit board layouts describe the detailed system design, including application of a planar optical waveguide interface

Fiber optic control system integration

A total fiber optic, integrated propulsion/flight control system concept for advanced fighter aircraft is presented. Fiber optic technology pertaining to this system is identified and evaluated for application readiness. A fiber optic sensor vendor survey was completed, and the results are reported. The advantages of centralized/direct architecture are reviewed, and the concept of the protocol branch is explained. Preliminary protocol branch selections are made based on the F-18/F404 application. Concepts for new optical tools are described. Development plans for the optical technology and the described system are included

A new survey for high velocity HI detections in the southern hemisphere

A new high-sensitivity HI survey of the southern sky was made south of Declination , at the Instituto Argentino de Radioastronomía (IAR), on a half-degree grid in galactic coordinates. A total of 50980 positions were observed. One of the goals of this survey was to search for high velocity clouds (HVCs). The HI profiles have been smoothed to a velocity resolution of 8 km s-1. The resulting rms noise falls in the range 0.015 to 0.020 K. We have detected 6848 high velocity (HV) components.Fil: Morras, Ricardo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Bajaja, Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Arnal, Edmundo Marcelo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Poppel, W. G. L.. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentin

Analysis, design, fabrication and testing of an optical tip clearance sensor

Analyses and the design, fabrication, and testing of an optical tip clearance sensor with intended application in aircraft propulsion control systems are reported. The design of a sensor test rig, evaluation of optical sensor components at elevated temperatures, sensor design principles, sensor test results at room temperature, and estimations of sensor accuracy at temperatures of an aircraft engine environment are discussed. Room temperature testing indicated possible measurement accuracies of less than 12.7 microns (0.5 mils). Ways to improve performance at engine operating temperatures are recommended. The potential of this tip clearance sensor is assessed

HI vinculado con regiones HII

Se están analizando observaciones de HI en las regiones Scorpios-Ophiuchus y Perseus donde Sivan (1974) observara en HI regiones HII de gran extensión angular.Asociación Argentina de Astronomí

OB Stars in the Solar Neighborhood I: Analysis of their Spatial Distribution

We present a newly-developed, three-dimensional spatial classification method, designed to analyze the spatial distribution of early type stars within the 1 kpc sphere around the Sun. We propose a distribution model formed by two intersecting disks -the Gould Belt (GB) and the Local Galactic Disk (LGD)- defined by their fundamental geometric parameters. Then, using a sample of about 550 stars of spectral types earlier than B6 and luminosity classes between III and V, with precise photometric distances of less than 1 kpc, we estimate for some spectral groups the parameters of our model, as well as single membership probabilities of GB and LGD stars, thus drawing a picture of the spatial distribution of young stars in the vicinity of the Sun.Comment: 28 pages including 9 Postscript figures, one of them in color. Accepted for publication in The Astronomical Journal, 30 January 200

A high sensitivity HI survey of the sky at delta < -25 deg Final data release

We present the final data release of the high sensitivity lambda 21-cm neutral hydrogen survey of the sky south of delta < -25 degr. A total of 50980 positions lying on a galactic coordinate grid with points spaced by (Delta l, Delta b) = ((0.5 deg)/cos b, 0.5 deg) were observed with the 30-m dish of the Instituto Argentino de Radioastronomia (IAR). The angular resolution of the survey is HPBW = 0.5 deg and the velocity coverage spans the interval -450 km/s to +400 km/s (LSR). The velocity resolution is 1.27 km/s and the final rms noise of the entire database is 0.07 K. The data are corrected for stray radiation and converted to brightness temperatures.Comment: 10 pages, 10 figures, accepted for publication by Astronomy & Astrophysic

HI Narrow Line Absorption in Dark Clouds

We have used the Arecibo telescope to carry out an survey of 31 dark clouds in the Taurus/Perseus region for narrow absorption features in HI ($\lambda$ 21cm) and OH (1667 and 1665 MHz) emission. We detected HI narrow self--absorption (HINSA) in 77% of the clouds that we observed. HINSA and OH emission, observed simultaneously are remarkably well correlated. Spectrally, they have the same nonthermal line width and the same line centroid velocity. Spatially, they both peak at the optically--selected central position of each cloud, and both fall off toward the cloud edges. Sources with clear HINSA feature have also been observed in transitions of CO, \13co, \c18o, and CI. HINSA exhibits better correlation with molecular tracers than with CI. The line width of the absorption feature, together with analyses of the relevant radiative transfer provide upper limits to the kinetic temperature of the gas producing the HINSA. Some sources must have a temperature close to or lower than 10 K. The correlation of column densities and line widths of HINSA with those characteristics of molecular tracers suggest that a significant fraction of the atomic hydrogen is located in the cold, well--shielded portions of molecular clouds, and is mixed with the molecular gas. The average number density ratio [HI]/[\h2] is $1.5\times10^{-3}$. The inferred HI density appears consistent with but is slightly higher than the value expected in steady state equilibrium between formation of HI via cosmic ray destruction of H$_2$ and destruction via formation of H$_2$ on grain surfaces. The distribution and abundance of atomic hydrogen in molecular clouds is a critical test of dark cloud chemistry and structure, including the issues of grain surface reaction rates, PDRs, circulation, and turbulent diffusion.Comment: 40 pages, 10 figures, accepted by Ap

Sister chromatid exchanges and micronuclei in peripheral lymphocytes of shoe factory workers exposed to solvents.

We examined sister chromatid exchanges (SCEs) and micronuclei (MN; cytokinesis-block method) in cultured peripheral lymphocytes from 52 female workers of two shoe factories and from 36 unexposed age- and sex-matched referents. The factory workers showed an elevated level of urinary hippuric acid, a biomarker of toluene exposure, and workplace air contained high concentrations of various organic solvents such as toluene, gasoline, acetone, and (in one of the plants only) ethylacetate and methylenediphenyl diisocyanate. The shoe factory workers showed a statistically significant higher frequency of micronucleated binucleate lymphocytes in comparison with the referents. This finding agreed with three preliminary MN determinations (each comprising 27-32 shoe workers and 16-20 controls) performed in one of the plants 2-5 years earlier. The shoe factory workers also had a lower average level of blood hemoglobin than the referents. In contrast, no difference was found between the groups in SCE analysis. Smokers showed significantly higher mean frequencies of SCEs per cell and high frequency cells (HFC) than nonsmokers. Aging was associated with increased MN rates and reduced cell proliferation. Polymorphism of the glutathione S-transferase M1 gene (GSTM1) did not affect the individual level of SCEs; but in smoking shoe workers an effect of the occupational exposure on the frequency of micronucleated cells could be seen only in GSTM1 null subjects. The low prevalence of the glutathione S-transferase T1 (GSTT1) null genotype precluded the evaluation of the influence of GSTT1 polymorphism. Our results show that the shoe factory workers have experienced genotoxic exposure, which is manifest as an increase in the frequency of MN, but not of SCEs, in peripheral lymphocytes. The exposures responsible for the MN induction could not be identified with certainty, but exposure to benzene in gasoline and methylenediphenyl diisocyanate may explain some of the findings