Figure 2. — A fuel crib showing the basic unit cell. At left is the thermocouple arrange- 

 ment in the longitudinal member and above is the arrangement in the transverse 

 member. The cross -sectional area of a member is A = t 2 and the side area is 

 B = tl, where t is the member thickness and I is the spacing on centers between 

 fuel members. 



Two identical members of length, £, make up the unit cell. They overlap and join at 

 right angles (fig. 2). Q is the nonuniform heat absorbed per unit ovendry mass. The 

 A and B subscripts refer to the transverse and longitudinal members, respectively. A 

 comparison standard for determining the effective heating number was established by 

 assuming uniform heating throughout the two members of the unit cell. 



Thomas and Simms (1963) used the moist fuel specific heat and the temperature rise 

 to ignition to determine the heat necessary to bring the fuel uniformly to ignition. 

 I have employed a method similar to that used by Byram and coworkers (1952), with two 



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