13,088 research outputs found
Linking Smallholders to Markets for Non-Traditional Agricultural Exports: a Review of Experiences in the Caribbean Basi
Evaluation of NASA-sponsored research on capital investment decision making in the civil aviation industry
Significant findings of three studies undertaken to provide the NASA Aircraft Energy Efficiency (ACEE) Office with information regarding how aircraft manufacturers and commercial airlines make investment decisions concerning the acquisition of new and derivative technology are analyzed and their general implications explored. Topics discussed include: the market for airline aircraft, factors affecting the corporate decision making process of air transport manufacturers, and flight equipment purchasing practices of representative air carriers
LANDSAT Study of Alteration Aureoles in Surface Rocks Overlying Petroleum Deposits
The author has identified the following significant results. A series of low altitude underflight remote sensing experiments were flown at Cement and Davenport oil fields, Oklahoma. An experimental algorithm which employs a sinusoidal stretch of brightness values was developed and applied to a January 1973 scene (bands 4, 5, and 6) of Cement. The results, although not spectacular, are extremely encouraging and for the first time demonstrate that the alteration anomaly at Cement may be defined through enhanced LANDSAT images
Approach range and velocity determination using laser sensors and retroreflector targets
A laser docking sensor study is currently in the third year of development. The design concept is considered to be validated. The concept is based on using standard radar techniques to provide range, velocity, and bearing information. Multiple targets are utilized to provide relative attitude data. The design requirements were to utilize existing space-qualifiable technology and require low system power, weight, and size yet, operate from 0.3 to 150 meters with a range accuracy greater than 3 millimeters and a range rate accuracy greater than 3 mm per second. The field of regard for the system is +/- 20 deg. The transmitter and receiver design features a diode laser, microlens beam steering, and power control as a function of range. The target design consists of five target sets, each having seven 3-inch retroreflectors, arranged around the docking port. The target map is stored in the sensor memory. Phase detection is used for ranging, with the frequency range-optimized. Coarse bearing measurement is provided by the scanning system (one set of binary optics) angle. Fine bearing measurement is provided by a quad detector. A MIL-STD-1750 A/B computer is used for processing. Initial test results indicate a probability of detection greater than 99 percent and a probability of false alarm less than 0.0001. The functional system is currently at the MIT/Lincoln Lab for demonstration
Integrated carbon dioxide reduction system feasibility study, part I Final report
Method for physical recovery of carbon dioxide from space cabin atmosphere and chemical recovery of metabolic oxyge
On the number of transversals in a class of Latin squares
Denote by the Latin square of order formed by the Cayley table of the additive group , where is an odd prime and is a positive integer. It is shown that for each there exists such that for all sufficiently large , the number of transversals in exceeds
A Global Review of Rural Community Enterprises: the long and winding road for creating viable businesses
A Simple Approach to Constructing Quasi-Sudoku-based Sliced Space-Filling Designs
Sliced Sudoku-based space-filling designs and, more generally, quasi-sliced
orthogonal array-based space-filling designs are useful experimental designs in
several contexts, including computer experiments with categorical in addition
to quantitative inputs and cross-validation. Here, we provide a straightforward
construction of doubly orthogonal quasi-Sudoku Latin squares which can be used
to generate sliced space-filling designs which achieve uniformity in one and
two-dimensional projections for both the full design and each slice. A
construction of quasi-sliced orthogonal arrays based on these constructed
doubly orthogonal quasi-Sudoku Latin squares is also provided and can, in turn,
be used to generate sliced space-filling designs which achieve uniformity in
one and two-dimensional projections for the full design and and uniformity in
two-dimensional projections for each slice. These constructions are very
practical to implement and yield a spectrum of design sizes and numbers of
factors not currently broadly available.Comment: 15 pages, 9 figure
Defect chemistry and characterization Hg(1-x)Cd(x)Te
Iodine doped single crystal samples of mercury cadmium telluride were annealed at temperatures varying from 450 C to 600 C in Hg vapor and quenched to room temperature. Hall effect measurements at 77 K on the crystals cooled to room temperature indicate the samples to be n-type after anneals at high Hg pressures whereas they turn p-type after anneals at low Hg pressures; the electron concentration increases with increase in Hg pressure. The results are explained on the basis that the crystals are saturated with (Hg,Cd)I2, with a fraction of the iodine being present as donor occupying tellurium lattice sites and a fraction being present as acceptors resulting from the iodine on tellurium lattice sites pairing with the doubly ionized native acceptor defects. The solubility of the donor species increases with increase in Hg pressure, whereas that of the acceptor species increases with decrease in Hg pressure. Equilibrium constants for the incorporation of the iodine species as well as the pairing reaction were established
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