Stage circumferential

DeWald RL, Faut MM, Taddonio RF, Neuwirth MG (1981) Severe lumbosacral spondylolisthesis in adolescents and children. Reduction and staged circumferential fusion. J Bone Joint Surg (Am) 63 619... 

For hydrodynamic turbomachines (Fig. 4.1-4), the speed of the fluid flow or the circumferential velocity of the radial impellers involved is of great importance for the pressure increase per stage (A p u2 p, where p is the density of the fluid, and u is the circumferential velocity). Obviously the high circumferential velocity required for effective pressure generation can be achieved by high angular speed and / or a suitable size of the impeller. 

Centrifugal pumps require appropriately large circumferential speed of the impellers and a number of serially arranged stages, in order to obtain the high-pressure differences. For efficient and economic operation the specific speed, nq, of the individual pump stages (n<, = n V0,5 / H0 75 V m3/s H, m n, min 1) should stay above 10 to 20. Too small a capacity or hydraulic power transmission will not provide favourable operating conditions and it is then recommended to focus on positive-displacement pumps alternatively. 

In industry, hydrostatic pressure testing of pipes is still widely used to assess their resistance to this type of failure. Typical results are shown in Fig. 6 [57, 58], where failure times of HDPE pipes are given as a function of the circumferential (or hoop) stress. At relatively high stresses, ductile failure is observed (stage I) although deformation is initially homogeneous, small local variations (arising from variations in the specimen thickness, for exam-... 

Investigations were carried out on a small turbomolecular pump intended for use in a helium leak detector (see Chapter 4). Measurements at 24 °C of KmdX He for a suitably backed nine-stage pump with a blade circumferential speed of 200 m s 1 yielded a value of 254. 

Processed shale is removed at the top of the retort. A circumferential weir is provided to maintain a constant bed height in the upper stage. Entrained shale particles are removed from the product vapor by high-efficiency cylones located in the vapor disengagement section. The dimensions of this top section area, in fact, determined by the cyclone configuration. Superheated steam (1200°f, 650°C) is... 

Confining pressure is 10 MPa in Fig. 1. The unloading point is elastic stage, in the increasing process of axial pressure, stress-strain curve is almost linear, the slope of axial strain is less than circumferential strain, that is, the rate of increase of axial strain of specimens is more that circumferential strain. 

Because aU the three stresses, radial, axial, and circumferential, are compression stress, it is less likely to form cracks and ffacmres in the sample during the stage of heating [32]. It is also found that both the radial stress and the circumferential stress are maximized at the bottom of the sample, whereas the maximum axial stress is... 

The jet s origin is usually assumed to be a circumferential break or a longitudinal leak of a vessel or pipe. The resulting jet is then limited to a particular direction. In the case of circumferential breaks, the jet may be orientated either axially or radially with respect to the pipe. Radial jets arise in the early stages of the separation of the two limbs of the pipe as a result of the counter-impingement of the two axial jets, one from each limb. The radial jet may persist for a sustained period if the motion of the limbs is arrested before they become misaligned. 

A final fast fracture stage, where the initial crack rapidly propagates into the metal as a stress shear failure (usually) along the entire length of the tank and then circumferentially at the end caps. Additionily ... 

Another version of SSLP is the composite reinforced line pipe (CRLP), in which glass-reinforced composite (at the wet and uncured stage) is circumferentially wound around a steel pipe. The composite provides increased pressure capacity and environmental protection against corrosion. Depending upon the requirement, the ratio of steel and composite (in terms of their thicknesses) can be adjusted during manufacturing. 

---