Hydrostatic testing other methods

DOT and TC regulations require the hydrostatic testing of compressed gas cylinders by water jacket or other suitable methods that provide accurate data [1, 2]. The hydrostatic test determines the total expansion and permanent expansion under specified test pressure. These expansion readings determine wall thickness, average wall stress, and level of yield strength of the steel. DOT or TC must approve in writing the type and operation of the test apparatus. 

High hydrostatic pressure (HHP) and pulsed electric fields (PEFs) are rather novel technologies where relatively little research has been carried out. These methods have mostly been tested in combination with other decontamination methods and also mostly on either microorganisms in vitro or on foods of animal origin (e.g. milk, eggs and meat) (Raso and Barbosa-Canovas, 2003 Ross et al., 2003). More research is needed in order to find out if such methods are applicable to the fresh produce industry. 

Figure 5 illustrates the applied stress field for the HM-modelling including both mechanical stresses and the hydrostatic fluid pressure. In this figure the bottom boundary is rigid in the y-direction and all other mechanical boundaries are free to move. An embedded domain method has also been tested to reduce the bottom boundary constraint. The 5 m X 5 m DFN was located in the centre of eight... 

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