Inflatable decelerators

Further modification of the FAE-II bomb is presented by Miller (Ref 3). This report describes an aerodynamic decelerator as follows Applying a Ram Air Inflatable Decelerator (RAID) as the aerodynamic decelerator system to meet the air-delivery requirements for the 2000-lb fuel air explosive (FAE) bomb. The delivery approach considered is to allow the bomb to free-fall in an unretarded configuration until it reaches the vicinity of the target. At this... 

Figure 15.2. Inflatable decelerator concepts. Courtesy of the Inflatable Re-entry Vehicle Experiment (IRVE) Project.

Reza S, Hund R, Kustas F, Willcockson W, Songer J (2007) Aerocapture Inflatable decelerator (AID) for planetary entry. 19th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar 21—24 May 2007, WUliamsburg, VA, AIAA 2007-2516. 

When the vehicle decelerates suddenly (as a result of a collision), an electric device detonates the azide, and the sudden surge of nitrogen inflates the bag to cushion the impact of the driver or passenger against the car s interior (Section 4.9). 

How does it work Ideally, it inflates only when severe front-end impact occurs it inflates very rapidly (in approximately 40 milliseconds), then deflates to provide a steady deceleration, cushioning the occupants from impact. A remarkably simple chemical reaction makes this a reality. 

Lastly, it may seem somewhat bizarre to associate a safety device with an explosion but this is the method used to inflate air bags (Figure 1.2), If a vehicle is involved in a frontal collision equivalent to hitting a brick wall at more than 12 to 15 miles per hour, then sensors detect the sudden deceleration and trigger an electrical device which detonates a mixture containing about 65 g of sodium azide (NaN3). The azide undergoes a relatively slow type of explosion... 

VLP events in silicic systems may also be associated with the passive extrusion of magma, as in the case of Mount St. Helens (Waite et al. 2008). The VLP events were the result of unsteady flow as the magma moved from a vertical to horizontal portion of the conduit just below the surface. The mechanism included inflation and deflation of cracks and also nearly horizontal single forces. The single forces were associated with acceleration and deceleration of magma as it moved through this portion of the conduit. 

At impact, the vehicle deceleration and its duration are measured. If certain iimits are exceeded, first the safety belt (lower limit value) and then the airbag (upper limit value) are activated. The firing is activated about 30 to 40 ms after the impact at a speed of 15 to 25 km/h (values vary for different manufacturers). The whole process Including activation, inflation, and discharge of the airbag caused by the impact of the passengers is completed in 70 to 80 ms. 

On the other hand, the decreasing rate of inflation - started in the U.S. in 1982 - is associated with expansionist policies of a higher budget deficit, with reduction in the interest rate, with increasing growth rate and with receding unemployment. These developments look like a deceleration course of stagflation rather than as a renewed trade off between inflation and unemployment. 

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