20,599 research outputs found
The Fog of War: Large-Scale Smoke Screening Operations of First Canadian Army in Northwest Europe
Smoke screens have been employed in sea and land warfare for many centuries for a variety of purposes. They have been used to conceal troop movements, to deceive the enemy as to combat strengths, point of attack, and preparations for offensive operations. During the Second World War all armies made use of smoke screns in their operations to a greater or lesser extent. Canada was no exception and was considered to be extremely innovative in the use of smoke equipment in ways for which it was not designed. The First Canadian Army first employed large-scale non-artillery-projected smoke screens during the campaign in Northwest Europe. For the first time, at least in the history of Canadian operations, units of trained specialists worked to lay down smoke screens in the field
Free-Flight Skin Temperature and Pressure Measurements on a Slightly Blunted 25 Deg Cone-Cylinder-Flare Configuration to a Mach Number of 9.89
Skin temperatures and surface pressures have been measured on a slightly blunted cone-cylinder-flare configuration to a maximum Mach number of 9.89 with a rocket-propelled model. The cone had a t o t a l angle of 25 deg and the flare had a 10 deg half-angle. Temperature data were obtained at eight cone locations, four cylinder locations, and seven flare locations; pressures were measured at one cone location, one cylinder location, and three flare locations. Four stages of propulsion were utilized and a reentry type of trajectory was employed in which the high-speed portion of flight was obtained by firing the last two stages during the descent of the model from a peak altitude of 99,400 feet. The Reynolds number at peak Mach number was 1.2 x 10(exp 6) per foot of model length. The model length was 6.68 feet. During the higher speed portions of flight, temperature measurements along one element of the nose cone indicated that the boundary layer was probably laminar, whereas on the opposite side of the nose the measurements indicated transitional or turbulent flow. Temperature distributions along one meridian of the model showed the flare to have the highest temperatures and the cylinder generally to have the lowest. A maximum temperature of 970 F was measured on the cone element showing the transitional or turbulent flow; along the opposite side of the model, the maximum temperatures of the cone, cylinder, and flare were 545 F, 340 F, and 680 F, respectively, at the corresponding time
Digital interface for bi-directional communication between a computer and a peripheral device
For transmission of data from the computer to the peripheral, the computer initially clears a flipflop which provides a select signal to a multiplexer. A data available signal or data strobe signal is produced while tht data is being provided to the interface. Setting of the flipflop causes a gate to provide to the peripherial a signal indicating that the interface has data available for transmission. The peripheral provides an acknowledge or strobe signal to transfer the data to the peripheral. For transmission of data from the peripheral to the computer, the computer presents the initially cleared flipflop. A data request signal from the peripheral indicates that the peripheral has data available for transmission to the computer. An acknowledge signal indicates that the interface is ready to receive data from the peripheral and to strobe that data into the interface
Signal-to-Noise Eigenmode Analysis of the Two-Year COBE Maps
To test a theory of cosmic microwave background fluctuations, it is natural
to expand an anisotropy map in an uncorrelated basis of linear combinations of
pixel amplitudes --- statistically-independent for both the noise and the
signal. These -eigenmodes are indispensible for rapid Bayesian analyses of
anisotropy experiments, applied here to the recently-released two-year COBE
{\it dmr} maps and the {\it firs} map. A 2-parameter model with an overall
band-power and a spectral tilt describes well inflation-based
theories. The band-powers for {\it all} the {\it dmr} + GHz
and {\it firs} 170 GHz maps agree, , and
are largely independent of tilt and degree of (sharp) -filtering. Further,
after optimal -filtering, the {\it dmr} maps reveal the same
tilt-independent large scale features and correlation function. The unfiltered
{\it dmr} + index is ; increasing the
-filtering gives a broad region at (1.0--1.2)0.5, a jump to
(1.4--1.6)0.5, then a drop to 0.8, the higher values clearly seen to be
driven by -power spectrum data points that do not fit single-tilt models.
These indices are nicely compatible with inflation values (0.8--1.2), but
not overwhelmingly so.Comment: submitted to Phys.Rev.Letters, 4 pages, uuencoded compressed
PostScript; also bdmr2.ps.Z, via anonymous ftp to ftp.cita.utoronto.ca, cd to
/pub/dick/yukawa; CITA-94-2
Shuttle program: OFT ascent/descent ancillary data requirements document
Requirements are presented for the ascent/descent (A/D) navigation and attitude-dependent ancillary data products to be generated for the space shuttle orbiter in support of the orbital flight test (OFT) flight test requirements, MPAD guidance and navigation performance assessment, and the mission evaluation team. The A/D ancillary data support for OFT mission evaluation activities is confined to providing postflight position, velocity, attitude, and associated navigation and attitude derived parameters for the Orbiter over particular flight phases and time intervals
OFT ascent/descent ancillary data requirements document
Requirements are presented for the ascent/descent (A/D) navigation and attitude-dependent ancillary data products to be generated for the space shuttle orbiter in support of orbital flight test requirements, MPAD guidance and navigation performance assessment, and the mission evaluation team. It was intended that this document serve as the sole requirements control instrument between MPB/MPAD and the A/D ancillary data users. The requirements are primarily functional in nature, but some detail level requirements are also included
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