Jenike theory

If a particle of the powder is larger than the outlet it will not flow out. If the outlet is several-fold larger than the particles, the powder may not flow out. If the outlet is manyfold larger than micrometer sized particles, the powder may not flow out. Obviously, extrapolating the failure function down to the region of extremely low stresses is not tenable because one moves into a regime where other mechanisms, in addition those of the Jenike theory, start to become significant. 

Buttolph, M.L., and Holland, D.A. (1990) Obsessive-compulsive disorders in pregnancy and childbirth. In Jenike, M.A., Baer, L., and Minichiello, W.E., eds. Obsessive-Compulsive Disorders Theory and Management, 2nd ed. Chicago Year Book Medical, pp. 89-97. 

Jenike MA Drug treatment of obsessive-compulsive disorder, in Obsessive Compulsive Disorders Theory and Management, 2nd Edition. Edited by Jenike MJ, Baer L, Minichiello WE. Littleton, MA, PSG Publishing, 1990, pp 249-282 Jenike MA, Baer L An open trial of Buspirone in OCD. Am J Psychiatry 145 1285-1286, 1988... 

Following the theory of Jenike,23 the solid normal stress acting in the shear plane can, in general, be calculated by simply dividing the external normal load by the shear surface area, which is assumed to correspond to the cross-sectional area of the cell. 

The basic character of non-fluidized gas-particle flow is the existence of contact pressure (or stress) among particles and between particles and the pipe wall. Both theoretical analyses and experimental results (Terzaghi, 1954 Johanson and Jenike, 1972 Li and Kwauk, 1989) showed that the pressure of the interstitial fluid in particulate material neither compresses nor increases the shear resistance of the particulate material. After Walker (1966) and Walters (1973), Li and Kwauk (1989) analyzed the stresses in a vertical pneumatic moving-bed transport tube by using the stress theory of particulate media mechanics and Mohr circles, shown in Figs. 19 and 20, and gave the following stress ratios at any point in the flow field ... 

A further use of the Jenike method is its extension to the critical structural design of storage vessels. Because pressures can be calculated, it is possible to design for actual conditions rather than estimates. Also, flow-corrective devices may be designed by using his theory. 

Shear strength of a bulk material in differing states of dilation is a key property of interest for flow considerations. The conventional hopper design method for mass flow is based upon critical state theory, and a Jenike shear cell is used to secure yield locus values upon which a design procedure is based. This technique is universally accepted, but not widely used for small hoppers for various reasons. Significant cost and expertise is required to obtain accurate values, compared with full-scale trials and... 

The Janssen theory describes pressures in a parallel-sided vessel. The corresponding theory for a converging channel came much later, and is normally attributed to Walker (1964, 1966), though it was first derived by Dabrowski (1957) and was probably also found by Jenike and others in the late 1950s. 

The most widely used switch theory for vertical walls was that of Jenike et al. (1973), which still underlies the flow pressure rules in the Australian Standard AS 3774 (1996), leading to a high ratio of design pressures for discharge to those after filling. This type of theory is still commonly expounded (Drescher 1991) as a formal part of silo pressure behaviour. 

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