Child safety seats are used for the safe transport of children in vehicles. A scintillating material for detecting individual species of radiation and including one or more groups of nanoparticles mixed with a fast electron scintillating material and extruded into a transparent film such that a light pulse is emitted when said transparent film is exposed to the species of radiation targeted by the nanoparticle groups. By not placing either barrier higher up in the well-bore, both of the barriers can remain in place during suspension and completion and workover operations, thus obviating the need to use a BOP stack to supplement well control. An accessory loads module models torque applied to the engine by accessory loads including at least one of a power steering pump, an air conditioning compressor, a water pump, and an alternator. The tapered gap is arranged closer to the central axis than a radially outermost point of the wall surface. 0 percent by weight, calculated as Fe with respect to weight of the silica-based material, and the source of bromide being present in an amount such that the weight ratio of Br to Fe is at least 0.