Reverse pitch fan with divided splitter

A guide vane arrangement is described for improving gas turbine performance in the reverse thrust mode. This flow straightening method produces low losses in the fluid entering a core engine during reverse thrust operations and allows large supercharging of the core engine during forward thrust

Molecular oxygen densities from rocket measurements of Lyman-alpha absorption profiles

Molecular oxygen density measurements in upper atmosphere by absorption spectroscopy using solar Lyman alpha radiatio

Performance of a UTC FW-4S solid propellant rocket motor under the command effects of simulated altitude and rotational spin

One United Technology Center FW-4S solid-propellant rocket motor was fired at an average simulated altitude of 103,000 ft while spinning about its axial centerline at 180 rpm. The objectives of the test program were to determine motor altitude ballistic performance including the measurement of the nonaxial thrust vector and to demonstrate structural integrity of the motor case and nozzle. These objectives are presented and discussed

Bright star observations using an unfiltered 1P21 phototube

Calibration curves for brighter navigational stars by unfiltered tracking phototube

Ground based photometry of potential navigation guide stars

Ground based photometry of potential navigation guide star

Influence of Induced Interactions on the Superfluid Transition in Dilute Fermi Gases

We calculate the effects of induced interactions on the transition temperature to the BCS state in dilute Fermi gases. For a pure Fermi system with 2 species having equal densities, the transition temperature is suppressed by a factor $(4e)^{1/3}\approx 2.2$, and for $\nu$ fermion species, the transition temperature is increased by a factor $(4e)^{\nu /3-1} \approx 2.2^{\nu-3}$. For mixtures of fermions and bosons the exchange of boson density fluctuations gives rise to an effective interaction, and we estimate the increase of the transition temperature due to this effect.Comment: 4 pages, 3 figure

A rocket-borne data-manipulation experiment using a microprocessor

The development of a data-manipulation experiment using a Z-80 microprocessor is described. The instrumentation is included in the payloads of two Nike Apache sounding rockets used in an investigation of energetic particle fluxes. The data from an array of solid-state detectors and an electrostatic analyzer is processed to give the energy spectrum as a function of pitch angle. The experiment performed well in its first flight test: Nike Apache 14.543 was launched from Wallops Island at 2315 EST on 19 June 1978. The system was designed to be easily adaptable to other data-manipulation requirements and some suggestions for further development are included

Wet chemical etching mechanism of silicon

We review what can be said on wet chemical etching of single crystals from the viewpoint of the science of crystal growth. Starting point is that there are smooth and rough crystal surfaces. The kinetics of smooth faces is controlled by a nucleation barrier that is absent on rough faces. The latter therefore etch faster by orders of magnitude. The analysis of the diamond crystal structure reveals that the {111} face is the only smooth face in this lattice-other faces might be smooth only because of surface reconstruction. In this way we explain the minimum of the etch rate in KOH:H2O in the <001> direction. Two critical predictions concerning the shape of the minimum of the etch rate close to <001> and the transition from isotropic to anisotropic etching in HF:HNO3 based solutions are tested experimentally. The results are in-agreement with the theor