12,685 research outputs found
Tool forms right angles in component leads
Hand tool forms right angles in electronic component leads so they fit the spaced holes of a printed circuit board. This tool firmly holds the leads at points near the component ends to prevent damage and provide accuracy
A Matroid Generalization of a Result on Row-Latin Rectangles
Let A be an m \times n matrix in which the entries of each row are all
distinct. Drisko showed that, if m \ge 2n-1, then A has a transversal: a set of
n distinct entries with no two in the same row or column. We generalize this to
matrices with entries in a matroid. For such a matrix A, we show that if each
row of A forms an independent set, then we can require the transversal to be
independent as well. We determine the complexity of an algorithm based on the
proof of this result. Lastly, we observe that m \ge 2n-1 appears to force the
existence of not merely one but many transversals. We discuss a number of
conjectures related to this observation (some of which involve matroids and
some of which do not).Comment: 9 pages, 5 figure
Competitive Markets and Aggregate Information
This paper shows that a competitive market structure is identically efficient to a Walrasian rational expectations market when risk-averse agents base trades only on unbiased private signals. Because price reflects the complete set of market information, it is a sufficient statistic. The economic role of competing market makers is thus to aggregate information efficiently.Market Structure
Tailcone on orbiter altitude attainable at the maximum ALT interface airspeed
A preflight analysis performed for verification of the ALT mated vehicle incidence angle which maximizes the post separation altitude attainment by the orbiter at the maximum approach and landing test (ALT) interface airspeed (300 KEAS) is discussed. In the analysis, altitude versus airspeed profiles are generated for each of the three incidence angles that include and bound the recommended incidence angle for both the forward and the aft cg tailcone on orbiter configurations. Results show that the recommended incidence angles maximize the orbiter post separation altitude attainable within an acceptable tradeoff between separation clearance capability and orbiter structural constraints. Within constraints, the incidence angle that maximizes the orbiter altitude at the maximum ALT interface airspeed for both the forward and aft cg orbiter tailcone on configurations is 6.0 deg. The requirement for a parametric analysis of orbiter altitude attainable at the maximum ALT interface airspeed is stated along with the specifications, assumptions, and analytical approach used to determine orbiter altitude attainable at the maximum ALT interface airspeed
Manual actuator
An actuator for an exercising machine employable by a crewman aboard a manned spacecraft is presented. The actuator is characterized by a force delivery arm projected from a rotary imput shaft of an exercising machine and having a force input handle extended orthogonally from its distal end. The handle includes a hand-grip configured to be received within the palm of the crewman's hand and a grid pivotally supported for angular displacement between a first position, wherein the grid is disposed in an overlying juxtaposition with the hand-grip, and a second position, angularly displaced from the first position, for affording access to the hand-grip, and a latching mechanism fixed to the sole of a shoe worn by the crewman for latching the shoe to the grid when the grid is in the first position
Conductive elastomeric extensometer
Bridge circuit, in which conductive elastomeric material is the variable leg, precisely measures surface area changes in the human body. Circuits are used singularly, or in quantity by adding elements and amplifier circuits. Elastomeric strips can be located in a form-fitting garment
Observations of the Non-Thermal X-ray Emission from the Galactic Supernova Remnant G347.3-0.5
G347.3-0.5 (RX J1713.7-3946) is a member of the new class of shell-type
Galactic supernova remnants (SNRs) that feature non-thermal components to their
X-ray emission. We have analyzed the X-ray spectrum of this SNR over a broad
energy range (0.5 to 30 keV) using archived data from observations made with
two satellites, the Roentgenstaellit (ROSAT) and the Advanced Satellite for
Cosmology and Astrophysics (ASCA), along with data from our own observations
made with the Rossi X-ray Timing Explorer (RXTE). Using a combination of the
models EQUIL and SRCUT to fit thermal and non-thermal emission, respectively,
from this SNR, we find evidence for a modest thermal component to G347.3-0.5's
diffuse emission with a corresponding energy of kT = 1.4 keV. We also obtain an
estimate of 70 TeV for the maximum energy of the cosmic-ray electrons that have
been accelerated by this SNR.Comment: 4 pages, 1 figure, to appear in "Neutron Stars in Supernova Remnants"
(ASP Conference Proceedings), eds P. O. Slane and B. M. Gaensle
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