Study of outgassing and decomposition of Space Shuttle heat protection tiles, fillers and adhesive

A purge and trap technique which was employed to collect and separate the chemicals desorbing from the space shuttle heat protection tiles is described. The instrumentation included a mass spectrometer and gas chromatograph

Phenology satellite experiment

The detection of a phenological event (the brown wave-vegetation senescence) for specific forest and crop types using ERTS-1 imagery is described. Data handling techniques included computer analysis and photo interpretation procedures. Computer analysis of ERTS-1 multispectral scanner digital tapes in all bands was used to give the relative changes of spectral reflectance with time of forests and specified crops. These data were obtained for a number of the study's twenty-four sites located within four north-south corridors across the United States. Analysis of ground observation photography and ERTS-1 imagery for sites in the Appalachian Corridor and Mississippi Valley Corridor indicates that the recession of vegetation development can be detected very well. Tentative conclusions are that specific phenological events such as crop maturity or leaf fall can be mapped for specific sites and possibly for entire regions

Effect of tail-fin span on stability and control characteristics of a Canard-controlled missile at supersonic Mach numbers

An experimental wind-tunnel investigation was conducted at Mach numbers from 1.60 to 3.50 to obtain the longitudinal and lateral-directional aerodynamic characteristics of a circular, cruciform, canard-controlled missile with variations in tail-fin span. In addition, comparisons were made with the experimental aerodynamic characteristics using three missile aeroprediction programs: MISSILE1, MISSILE2, and NSWCDM. The results of the investigation indicate that for the test Mach number range, canard roll control at low angles of attack is feasible on tail-fin configurations with tail-to-canard span ratios of less than or equal to 0.75. The conards are effective pitch and yaw control devices on each tail-fin span configuration tested. Programs MISSILE1 and MISSILE2 provide very good predictions of longitudinal aerodynamic characteristics and fair predictions of lateral-directional aerodynamic characteristics at low angles of attack, with MISSILE2 predictions generally in better agreement with test data. Program NSWCDM provides good longitudinal and lateral-directional aerodynamic predictions that improve with increases in tail-tin span

Specifying ODP computational objects in Z

The computational viewpoint contained within the Reference Model of Open Distributed Processing (RM-ODP) shows how collections of objects can be configured within a distributed system to enable interworking. It prescribes certain capabilities that such objects are expected to possess and structuring rules that apply to how these objects can be configured with one another. This paper highlights how the specification language Z can be used to formalise these capabilities and the associated structuring rules, thereby enabling specifications of ODP systems from the computational viewpoint to be achieved

Integrating Item Accuracy and Reaction Time to Improve the Measurement of Inhibitory Control Abilities in Early Childhood

Efforts to improve children’s executive function are often hampered by the lack of measures that are optimized for use during the transition from preschool to elementary school. Whereas preschool-based measures often emphasize response accuracy, elementary school-based measures emphasize reaction time (RT)—especially for measures inhibitory control (IC) tasks that typically have a speeded component. The primary objective of this study was to test in a preschool-aged sample whether the joint use of item-level accuracy and RT data resulted in improved scoring for three IC tasks relative to scores derived from accuracy data alone. Generally, the joint use of item-level accuracy and RT data resulted in modest improvements in the measurement precision of IC abilities. Moreover, the joint use of item-level accuracy and RT helped eliminate floor and ceiling effects that occurred when accuracy data were considered alone. Results are discussed with respect to the importance of scoring IC tasks in ways that are maximally informative for program evaluation and longitudinal modeling

Short-Wavelength Light-Blocking Eyeglasses Attenuate Symptoms of Eye Fatigue

Purpose: The purpose of this study was to determine whether subjects who wear short wavelength–blocking eyeglasses during computer tasks exhibit less visual fatigue and report fewer symptoms of visual discomfort than subjects wearing eyeglasses with clear lenses.Methods: A total of 36 healthy subjects (20 male; 16 female) was randomized to wearing no-block, low-blocking, or high-blocking eyeglasses while performing a 2-hour computer task. A masked grader measured critical flicker fusion frequency (CFF) as a metric of eye fatigue and evaluated symptoms of eye strain with a 15-item questionnaire before and after computer use.Results: We found that the change in CFF after the computer task was significantly more positive (i.e., less eye fatigue) in the high-block versus the no-block (P = 0.027) and low-block (P = 0.008) groups. Moreover, random assignment to the high-block group but not to the low-block group predicted a more positive change in CFF (i.e., less eye fatigue) following the computer task (adjusted β = 2.310; P = 0.002). Additionally, subjects wearing high-blocking eyeglasses reported significantly less feeling pain around/inside the eye (P = 0.0063), less feeling that the eyes were heavy (P = 0.0189), and less feeling that the eyes were itchy (P = 0.0043) following the computer task, when compared to subjects not wearing high-blocking lenses.Conclusions: Our results support the hypothesis that short-wavelength light-blocking eyeglasses may reduce eye strain associated with computer use based on a physiologic correlate of eye fatigue and on subjects\u27 reporting of symptoms typically associated with eye strain

The Infrared Massive Stellar Content of M83

We present an analysis of archival Spitzer images and new ground-based and Hubble Space Telescope (HST) near-infrared (IR) and optical images of the field of M83 with the goal of identifying rare, dusty, evolved massive stars. We present point source catalogs consisting of 3778 objects from $Spitzer$ Infrared Array Camera (IRAC) Band 1 (3.6 $\mu$m) and Band 2 (4.5 $\mu$m), and 975 objects identified in Magellan 6.5m FourStar near-IR $J$ and $K_{\rm s}$ images. A combined catalog of coordinate matched near- and mid-IR point sources yields 221 objects in the field of M83. Using this photometry we identify 185 massive evolved stellar candidates based on their location in color-magnitude and color-color diagrams. We estimate the background contamination to our stellar candidate lists and further classify candidates based on their appearance in $HST$ Wide Field Camera 3 (WFC3) observations of M83. We find 49 strong candidates for massive stars which are very promising objects for spectroscopic follow-up. Based on their location in a $B-V$ versus $V-I$ diagram, we expect at least 24, or roughly 50%, to be confirmed as red supergiants.Comment: 32 pages, 23 figures, accepted for publication in A&

Phenology satellite experiment

There are no author-identified significant results in this report

Sparticle Mass Spectrum in Grand Unified Theories

We carry out a detailed analysis of sparticle mass spectrum in supersymmetric grand unified theories. We consider the spectroscopy of the squarks and sleptons in SU(5) and SO(10) grand unified theories, and show how the underlying supersymmetry breaking parameters of these theories can be determined from a measurement of different sparticle masses. This analysis is done analytically by integrating the one-loop renormalization group equations with appropriate boundary conditions implied by the underlying grand unified gauge group. We also consider the impact of non-universal gaugino masses on the sparticle spectrum, especially the neutralino and chargino masses which arise in supersymmetric grand unified theories with non-minimal gauge kinetic function. In particular, we study the interrelationships between the squark and slepton masses which arise in grand unified theories at the one-loop level, which can be used to distinguish between the different underlying gauge groups and their breaking pattern to the Standard Model gauge group. We also comment on the corrections that can affect these one-loop results.Comment: 19 pages, 6 figure

The use of ERTS-1 multispectral imagery for crop identification in a semi-arid climate

Crop identification using multispectral satellite imagery and multivariate pattern recognition was used to identify wheat accurately in Greeley County, Kansas. A classification accuracy of 97 percent was found for wheat and the wheat estimate in hectares was within 5 percent of the USDA's Statistical Reporting Service estimate for 1973. The multispectral response of cotton and sorghum in Texas was not unique enough to distinguish between them nor to separate them from other cultivated crops