Force development, positive resist

Resistance functions have been evaluated in numerical compu-tations15831 for low Reynolds number flows past spherical particles, droplets and bubbles in cylindrical tubes. The undisturbed fluid may be at rest or subject to a pressure-driven flow. A spectral boundary element method was employed to calculate the resistance force for torque-free bodies in three cases (a) rigid solids, (b) fluid droplets with viscosity ratio of unity, and (c) bubbles with viscosity ratio of zero. A lubrication theory was developed to predict the limiting resistance of bodies near contact with the cylinder walls. Compact algebraic expressions were derived to accurately represent the numerical data over the entire range of particle positions in a tube for all particle diameters ranging from nearly zero up to almost the tube diameter. The resistance functions formulated are consistent with known analytical results and are presented in a form suitable for further studies of particle migration in cylindrical vessels. 

The post-exposure treatment of photopolymerized structures in resin and resist is of critical importance for the final retrieval of 3D structures [77]. Since development of positive or negative resists and resins is a wet process, the damaging effect of capillary forces should be considered during the rinsing and drying of the samples. 

Stress is the internal resistance, or counterfource, of a material to the distorting effects of an external force or load. These counterforces tend to return the atoms to their normal positions. The total resistance developed is equal to the external load. This resistance is known as stress. 

A torsional impact test, developed by the GMC Technical Center, Warren, Mich., was used to compare the relative toughness and impact resistance of structural adhesives. In this test, a 3.6-lb. weight falls in a 20-inch, 90 -arc to impact a one-half inch overlap bonded lap shear positioned at a right angle to the bond. The impact scale reads directly in inch-pounds of force needed to break the bond. Sixty inch-pounds is the limit of the test. Steel and aluminum lap shears severely deform near this limit. Table 4 illustrates the typical values obtained. 

In Fig. 1.20 the positive mechanical reactances are symbolized by inductors and negative mechanical reactances are symbolized by capacitors as would be true in the analogous electrical situation. The constant applied force generator is symbolized as a voltage source. Also in Fig. 1.20, Rr is identified as PocSRi 2o>a/c), whereas Kh is identified as poc S /Vq and M, as pocSXi )/o>. Unlike the common electrical situation, however, those elements that stem from radiation phenomena, such as R and M, are themselves frequency dependent. This complication will be dealt with after the model has been more fuUy developed. The circuit of Fig. 1.20, though useful, can only be an intermediate result as it does not involve any of the purely electrical properties of the loudspeaker such as the voice coil resistance or self-inductance. In addition, whenever the voice coil is in motion it has induced in it a back electromotive force (emf) of size Blu that opposes the current in the voice coil. This situation is represented schematically in Fig. 1.21. 

---