Off-surface infrared flow visualization

A method for visualizing off-surface flows is provided. The method consists of releasing a gas with infrared absorbing and emitting characteristics into a fluid flow and imaging the flow with an infrared imaging system. This method allows for visualization of off-surface fluid flow in-flight. The novelty of this method is found in providing an apparatus for flow visualization which is contained within the aircraft so as not to disrupt the airflow around the aircraft, is effective at various speeds and altitudes, and is longer-lasting than previous methods of flow visualization

Twinning Deformation in Magnesium Compressed along the C-Axis(Physics)

Deformation twinnings in magnesium activated on the c-axis compression were investigated by light and electron transmission microscopies. Well-known twin forms of {1013} and {3034} habit planes were confirmed again, but {1013} twins were frequently observed to occur in groups along {3034} or grow from {1013} habit to {3034} habit. Transmission electron microscopic observations revealed that the well-developed {3034} habit twin has the same orientation relationship with the parent crystal as the {1013} twin. From these observations, it is concluded that the well-developed {3034} habit twins are the {1013} twins developed along {3034} planes. A possible mechanism of the habit plane change is described and the relation between the twin and the compression band is discussed

Manufacturing requirements

In recent years, natural laminar flow (NLF) has been proven to be achievable on modern smooth airframe surfaces over a range of cruise flight conditions representative of most current business and commuter aircraft. Published waviness and boundary layer transition measurements on several modern metal and composite airframes have demonstrated the fact that achievable surface waviness is readily compatible with laminar flow requirements. Currently, the principal challenge to the manufacture of NLF-compatible surfaces is two-dimensional roughness in the form of steps and gaps at structural joints. Results of recent NASA investigations on manufacturing tolerances for NLF surfaces, including results of a flight experiment are given. Based on recent research, recommendations are given for conservative manufacturing tolerances for waviness and shaped steps

{1122} <1123> Slip System in Magnesium

The slip mode operative in the c-axis compression of magnesium was examined using precisely-oriented single crystals. From recorded stress-strain curves and observations with light and transmission electron microscopes, it was found that (1) the {1122} slip system operates at all temperatures investigated (from room temperature to 500℃), (2) the work hardening rate of this slip system is very high especially below 200℃, (3) the Burgers vector of the dislocation for the slip system is 1/3 , and (4) the dislocation has a strong preference to lie along a basal plane, which means that the edge dislocation is much less mobile than the screw dislocation. The ductility of polycrystalline magnesium is discussed from above observations

Measurement by FIB on the ISS: Two Emissions of Solar Neutrons Detected?

A new type of solar neutron detector (FIB) was launched onboard the Space Shuttle Endeavour on July 16, 2009, and it began collecting data at the International Space Station (ISS) on August 25, 2009. This paper summarizes the three years of observations obtained by the solar neutron detector FIB until the end of July 2012. The solar neutron detector FIB can determine both the energy and arrival direction of neutrons. We measured the energy spectra of background neutrons over the SAA region and elsewhere, and found the typical trigger rates to be 20 counts/sec and 0.22 counts/sec, respectively. It is possible to identify solar neutrons to within a level of 0.028 counts/sec, provided that directional information is applied. Solar neutrons were observed in association with the M-class solar flares that occurred on March 7 (M3.7) and June 7 (M2.5) of 2011. This marked the first time that neutrons were observed in M-class solar flares. A possible interpretaion of the prodcution process is provided.Comment: 36 pages, 16 figures, and 3 Tables; Advanced in Astronmy, 2012, Special issue on Cosmic Ray Variablity:Century of Its Obseravtion