Elongated cylinder

An EPAM artificial muscle actuator installed on a full-size plastic model of a human skeleton arm is shown in Figure 21.9. The actuator is acting much like a bicep. The artificial bicep is a rolled actuator, made by scrolling EPAM material into a cylindrical shape. Upon application of a voltage, the cylinder elongates. This particular muscle was capable of about 30% strain and about 2 kg of force. This mostly hollow muscle was not packaged for practical use nor was the force and hfetime sufficient for a practical elbow actuator. Nonetheless, this aetuator conveys the promise of EPAM for prosthetics. 

The general analysis, while not difficult, is complicated however, the limiting case of the very elongated, essentially cylindrical drop is not hard to treat. Consider a section of the elongated cylinder of volume V (Fig. II-18h). The centrifugal force on a volume element is u rAp, where w is the speed of revolution and Ap the difference in density. The potential energy at distance r from the axis of revolution is then w r Apfl, and the total potential energy for the... 

Most bones of the human skeleton are composed of two structurally distinct types of tissue compact (dense) and trabecular (cancellous, spongy) bone. Both types contain the same elements cells ( osteocytes) embedded in a mineralised matrix and connected by small canals ( canaliculi ). In compact bone, which makes up 85% of the skeleton, these components form elongated cylinders of concentric lamellae surrounding a central blood vessel (called osteon or Haversian system). Cancellous bone, in contrast, forms thin,... 

Fig. 9. Stress distribution on a solid cylinder in elongational flow (the flow direction is x)...

Metals Company used a commercial centrifugal atomizer to produce elongated droplets quenched with air. This atomizer has a spinner consisting of a steel cylinder with numerous fine holes along the barrel. The atomization system, while generating large output and high yield, allows variation of the spinner speed and hole size, adjustment of the melt temperature, and control of the atmosphere if necessary. 

In the model, the internal structure of the root is described as three concentric cylinders corresponding to the central stele, the cortex and the wall layers. Diffu-sivities and respiration rates differ in the different tissues. The model allows for the axial diffusion of O2 through the cortical gas spaces, radial diffusion into the root tissues, and simultaneous consumption in respiration and loss to the soil. A steady state is assumed, in which the flux of O2 across the root base equals the net consumption in root respiration and loss to the soil. This is realistic because root elongation is in general slow compared with gas transport. The basic equation is... 

Figure 1.13. Mechanism of rupturing. Under shear, drops elongate into long cylinders (a) that undergo a Rayleigh instability leading to identical aligned droplets (b). (Adapted from [149].)...

A few particles, such as spores, seem to be rather well approximated by spheroids, and there are many examples of elongated particles which may fairly well be described as infinite cylinders. Our next step toward understanding extinction by nonspherical particles is to consider calculations for these two shapes. To a limited extent this has already been done spheroids small compared with the wavelength in Chapter 5 and normally illuminated cylinders in Chapter 8. We remove these restrictions in this section measurements are presented in the following section. Because calculations for these shapes are more difficult than for spheres, we shall rely heavily on those of others. 

A third model involves an elongated cylinder, length Z, radius h. The cross-section is now %Z(2a+2 ), the factor % owing to the possible orientation of the target relative to the alpha particle. Then by the same argument... 

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