James bundles

We study cubical sets without degeneracies, which we call {square}-sets. These sets arise naturally in a number of settings and they have a beautiful intrinsic geometry; in particular a {square}-set C has an infinite family of associated {square}-sets Ji(C), for i = 1, 2, ..., which we call James complexes. There are mock bundle projections pi: |Ji(C)| -> |C| (which we call James bundles) defining classes in unstable cohomotopy which generalise the classical James–Hopf invariants of {Omega}(S2). The algebra of these classes mimics the algebra of the cohomotopy of {Omega}(S2) and the reduction to cohomology defines a sequence of natural characteristic classes for a {square}-set. An associated map to BO leads to a generalised cohomology theory with geometric interpretation similar to that for Mahowald orientation

Performance of a Brayton power system with a space type radiator

Test results of an experimental investigation to measure Brayton engine performance while operating at the sink temperatures of a typical low earth orbit are presented. The results indicate that the radiator area was slightly oversized. The steady state and transient responses of the power system to the sink temperatures in orbit were measured. During the orbital operation, the engine did not reach the steady state operation of either sun or shade conditions. The alternator power variation during orbit was + or - 4 percent from its mean value of 9.3 kilowatts

A search for experiments to exploit the space shuttle environment, volume 1

A search for worthwhile experiments in pure and applied physics and chemistry which might take advantage of conditions achievable aboard the space shuttle is documented. Of particular interest were the very large pumping speeds at high or ultra high vacuum, the highly nonequilibrium composition of the ambient atmosphere, and the relative absence of gravitational effects. Ideas and suggestions were solicated in the course of visits to 31 research establishments in Western Europe, India, and Japan; conversations with over 90 scientists; and presentations at 3 international meetings. Intriguing possibilities emerged in the following arenas: (1) spectroscopy of the transition state in chemical reactions; (2) flame structure and analysis; (3) solid propellant combustion; (4) analysis of atmospheric composition; (5) turbulence effects on aerosol coagulation

Potassium condensing tests of horizontal multitube convective and radiative condensers operating at vapor temperatures of 1250 deg to 1500 deg F

Potassium condensing tests of horizontal multitube convective and radiative condenser operating at vapor temperature

A Method of Measuring Jet Thrust of Turbojet Engines in Flight Installations

Measurement of the jet thrust of a turbojet engine in flight becomes more difficult as the number and complexity of the engine components increase. It is desirable, therefore, that a general correlation of jet thrust be developed which is applicable to a simple direct reading thrustmeter. In view of this need a correlation is presented which is independent of flight conditions and applicable to both non-afterburning and afterburning engines equipped with nonejector type fixed- and variable-area convergent exhaust nozzles. The general equation used in this correlation was derived from the theoretical jet-thrust equation for a choked convergent nozzle. The data used to verify the correlation were obtained over a range of altitudes from 10,000 to 54,000 feet and a range of flight Mach numbers from 0.4 to 1.1. A thrustometer based on this equation was installed on an afterburning turbojet engine equipped with a fixed area convergent exhaust nozzle. The results indicated that a meter based on this correlation would be applicable to a flight installation and that the probable error in thrust measurement would be approximately + or -1.5 percent provided the exhaust-nozzle thrust coefficient is known