Effect of Diethylenetriamine and Triethylamine sensitization on the critical diameter of Nitromethane

In this work, the critical diameter for detonation was measured for Nitromethane (NM) sensitized with two different amines: Diethylenetriamine (DETA) and Triethylamine (TEA). The critical diameter in glass and polyvinylchloride tubes is found to decrease rapidly as the amount of sensitizer is increased, then increase past a critical amount of sensitizer. Thus the critical diameter reaches a minimum at a critical concentration of sensitizer. It was also found that the critical diameter is lower with DETA than with TEA

Variation in Permeability and Treatability in Shortleaf Pine and Yellow Poplar

Superficial gas permeability determinations were made for longitudinal, radial, and tangential flow on samples removed from different heights, radii, and distances along the radii in a young and a mature shortleaf pine (Pinus echinata Mill.) and in a yellow poplar (Liriodendron tulipifera L.). Permeability was measured at a mean pressure of 2.2 atmospheres and the wood was maintained at about 18% moisture content. Some of the samples were then pressure-treated with creosote under controlled conditions to estimate treatability. Specific gravity and latewood per cent were also determined. In the young pine, position in the tree showed no effect on permeability, whereas in the mature pine a slight increase with height and a sharp increase with distance from the pith were detected. In yellow poplar, an increase of permeability with distance outwards along the radius was detected, but no consistent height change. Treatability, particularly retention, was moderately correlated with permeability, particularly in shortleaf pine. In yellow poplar, inclusion of permeability values for all three structural directions was necessary to obtain correlation. All relationships were improved by transforming the permeability logarithmically. Specific gravity and latewood relationships with permeability were conflicting. Use of a mean pressure higher than atmospheric appeared to be advantageous in permeability determinations

Enhanced reverse saturable absorption and optical limiting in heavy-atom-substituted phthalocyanines

The reverse saturable absorption and the optical-limiting response of metal phthalocyanines can be enhanced by use of the heavy-atom effect. Phthalocyanines containing heavy-metal atoms, such as In, Sn, and Pb, show a nearly factor-of-2 enhancement in the ratio of effective excited-state to ground-state absorption cross sections compared with those containing lighter atoms, such as Al and Si. In an f/8 optical geometry, homogeneous solutions of heavy-metal phthalocyanines, at 30% linear transmission, limit 8-ns 532-nm laser pulses to ≤ 3 µJ the energy for 50% probability of eye damage) for incident energies as high as 800 µJ

Evolved Navigation Control for Unmanned Aerial Vehicles

Whether evolutionary robotics (ER) controllers evolve in simulation or on real robots, realworld performance is the true test of an evolved controller. Controllers must overcome the noise inherent in real environments to operate robots efficiently and safely. To prevent a poorly performing controller from damaging a vehicle—susceptible vehicles includ

Effect of Specimen Length on Longitudinal Gas Permeability in Hardwoods

A study was carried out to determine whether the longitudinal gas permeability of hardwoods is affected by specimen length. The results indicate that in most woods tested, the permeability remains constant as length is reduced, except for lengths below 0.75 inch. Thereafter, with decreasing specimen length, permeability increases drastically. The large differences in permeability of samples of different length are attributed to random blockages in the capillary structure of the wood