22,388 research outputs found
Summary refurbishment cost study of the thermal protection system of a space shuttle vehicle
Analysis of costs to refurbish thermal protection system for space shuttle
Solid state image sensor research
Solid state image sensing devices developed for meteorological satellite application
Using LANDSAT digital data for estimating green biomass
The author has identified the following significant results. Relationships between the quantity of mixed prairie rangeland vegetation and LANDSAT MSS response were studied during four growing seasons at test sites throughout the United States Great Plans region. A LANDSAT derived parameter, the normalized difference was developed from theoretical considerations fro statistical estimation of the amount and seasonal condition of rangeland vegetation. This parameter was tested for application to local assessment of green forage biomass and regional monitoring of range feed conditions and drought. Results show that for grasslands in the Great Plains with near continuous vegetative cover and free of heavy brush and forbs, the LANDSAT digital data can provide a useful estimate of the quantity of green forage biomass (within 250 kg/ha), and at least five levels of pasture and range feed conditions can be adequately mapped for extended regions
Refurbishment cost study of the thermal protection system of a space shuttle vehicle. Phase 2: Supplement
The labor costs and techniques associated with the maintenance of a bonded-on ablator thermal protection system (TPS) concept, suitable for Space Shuttle application are examined. The baseline approach to TPS attachment involves bonding reusable surface insulation (RSI) and/or ablators to the structural skin of the vehicle. The RSI and/or ablators in the form of either flat or contoured panels can be bonded to the skin of the primary structure directly or by way of an intermediate silicone foam rubber pad. The use of foam rubber pads permits the use of buckling skins and protruding heat rivets on the primary structure, minimizing structural weight and fabrication costs. In the case of the RSI, the foam rubber pad serves as a required strain isolator. For purpose of comparison, test data were obtained for an installation with and without the use of a strain isolator. The refurbishment aspects of a bonded-on RSI concept (without a strain isolator) were examined experimentally along with several externally removable panel concepts employing both ablator and RSI TPS. The various concepts are compared
Research on low voltage electroluminescent devices with storage, phase 1 Final report, 1 May 1967 - 29 Feb. 1968
Materials for electroluminescent display panel based on carrier injectio
Broad-line region structure and kinematics in the radio galaxy 3C 120
Broad emission lines originate in the surroundings of supermassive black
holes in the centers of active galactic nuclei (AGN). One method to investigate
the extent, structure, and kinematics of the BLR is to study the continuum and
line profile variability in AGN. We selected the radio-loud Seyfert 1 galaxy 3C
120 as a target for this study. We took spectra with a high signal-to-noise
ratio of 3C 120 with the 9.2m Hobby-Eberly Telescope between Sept. 2008 and
March 2009. In parallel, we photometrically monitored the continuum flux at the
Wise observatory. We analyzed the continuum and line profile variations in
detail (1D and 2D reverberation mapping) and modeled the geometry of the
line-emitting regions based on the line profiles. We show that the BLR in 3C
120 is stratified with respect to the distance of the line-emitting regions
from the center with respect to the line widths (FWHM) of the rms profiles and
with respect to the variability amplitude of the emission lines. The emission
line wings of H{\alpha} and H{\beta} respond much faster than their central
region. This is explained by accretion disk models. In addition, these lines
show a stronger response in the red wings. However, the velocity-delay maps of
the helium lines show a stronger response in the blue wing. Furthermore, the
HeII{\lambda}4686 line responds faster in the blue wing in contradiction to
observations made one and a half years later when the galaxy was in a lower
state. The faster response in the blue wing is an indication for central
outflow motions when this galaxy was in a bright state during our observations.
The vertical BLR structure in 3C 120 coincides with that of other AGN. We
confirm the general trend: the emission lines of narrow line AGN originate at
larger distances from the midplane than AGN with broader emission lines.Comment: 18 pages, 25 figures, Astronomy & Astrophysics in pres
Relativistic Klein-Gordon-Maxwell multistream model for quantum plasmas
A multistream model for spinless electrons in a relativistic quantum plasma
is introduced by means of a suitable fluid-like version of the
Klein-Gordon-Maxwell system. The one and two-stream cases are treated in
detail. A new linear instability condition for two-stream quantum plasmas is
obtained, generalizing the previously known non-relativistic results. In both
the one and two-stream cases, steady-state solutions reduce the model to a set
of coupled nonlinear ordinary differential equations, which can be numerically
solved, yielding a manifold of nonlinear periodic and soliton structures. The
validity conditions for the applicability of the model are addressed
Social Brain Development in Williams Syndrome: The Current Status and Directions for Future Research
Williams syndrome (WS) is a neurodevelopmental condition that occurs as a result of a contiguous deletion of ∼26–28 genes on chromosome 7q11.23. WS is often associated with a distinctive social phenotype characterized by an increased affinity toward processing faces, reduced sensitivity to fear related social stimuli and a reduced ability to form concrete social relationships. Understanding the biological mechanisms that underlie the social phenotype in WS may elucidate genetic and neural factors influencing the typical development of the social brain. In this article, we review available studies investigating the social phenotype of WS throughout development and neuroimaging studies investigating brain structure and function as related to social and emotional functioning in this condition. This review makes an important contribution by highlighting several neuro-behavioral mechanisms that may be a cause or a consequence of atypical social development in WS. In particular, we discuss how distinctive social behaviors in WS may be associated with alterations or delays in the cortical representation of faces, connectivity within the ventral stream, structure and function of the amygdala and how long- and short-range connections develop within the brain. We integrate research on typical brain development and from existing behavioral and neuroimaging research on WS. We conclude with a discussion of how genetic and environmental factors might interact to influence social brain development in WS and how future neuroimaging and behavioral research can further elucidate social brain development in WS. Lastly, we describe how ongoing studies may translate to improved social developmental outcomes for individuals with WS
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