Jet engine air intake system

An axisymmetric air intake system for a jet aircraft engine comprising a fixed cowl extending outwardly from the face of the engine, a centerbody coaxially disposed within the cowl, and an actuator for axially displacing the centerbody within the cowl was developed. The cowl and centerbody define a main airflow passageway therebetween, the configuration of which is changed by displacement of the centerbody. The centerbody includes a forwardly-located closeable air inlet which communicates with a centerbody auxiliary airflow passageway to provide auxiliary airflow to the engine. In one embodiment, a system for opening and closing the centerbody air inlet is provided by a dual-member centerbody, the forward member of which may be displaced axially with respect to the aft member

Aircraft engine nozzle

A variable area exit nozzle arrangement for an aircraft engine was a substantially reduced length and weight which comprises a number of longitudinally movable radial vanes and a number of fixed radial vanes. The movable radial vanes are alternately disposed with respect to the fixed radial vanes. A means is provided for displacing the movable vanes along the longitudinal axis of the engine relative to the fixed radial vanes which extend across the main exhaust flow of the engine

Analytical studies of in-reactor tests of a nuclear light bulb unit cell

Analytical studies of in-reactor tests of nuclear light bulb unit cell using Pewee, nuclear furnace, and high flux isotope reactor

How biased are maximum entropy models?

Maximum entropy models have become popular statistical models in neuroscience and other areas in biology, and can be useful tools for obtaining estimates of mutual information in biological systems. However, maximum entropy models fit to small data sets can be subject to sampling bias; i.e. the true entropy of the data can be severely underestimated. Here we study the sampling properties of estimates of the entropy obtained from maximum entropy models. We show that if the data is generated by a distribution that lies in the model class, the bias is equal to the number of parameters divided by twice the number of observations. However, in practice, the true distribution is usually outside the model class, and we show here that this misspecification can lead to much larger bias. We provide a perturbative approximation of the maximally expected bias when the true model is out of model class, and we illustrate our results using numerical simulations of an Ising model; i.e. the second-order maximum entropy distribution on binary data.

Analytical studies of nuclear light bulb engine radiant heat transfer and performance characteristics

Analytical model of nuclear light bulb engine radiant heat transfer and engine performance, dynamics and control, heat loads and shutdown characteristic

The Military Munitions Rule and Environmental Regulation of Munitions

In the current post-Cold War era, when the need for combat readiness no longer seems necessary, the training activities of the United States military have come under fire. Military training sites across the nation are littered with spent munitions and unexploded ordnance, the result of decades of weapons development and training exercises. The problem is that these military munitions contain materials and chemicals which are potentially hazardous to the environment, and their destruction and cleanup pose special environmental and safety concerns. Congress has tried to strike a balance between the United States military\u27s need for continued training and the Environmental Protection Agency\u27s (EPA) desire to have the military clean up its hazardous waste sites. To do this, Congress enacted the Military Munitions Rule (Munitions Rule), which, if administered properly, is designed to effectively accomplish the goals of both the military and the EPA. However, the Munitions Rule is already the subject of litigation and controversy, leading some to question its actual effectiveness

Studies of nuclear light bulb start-up conditions and engine dynamics

Deep Space Network for two-way communications with unmanned spacecraft at planetary distances - Vol.