Back-bending effect

The back-bending effect, i.e., the drastic change of the moment of inertia (at about I s 16h for some rare-earth nuclei) was first observed experimentally by Johnson et al. (1971). The explanation of the effect, on the basis of sudden nucleon angular momentum alignment, was given by Stephens and Simon (1972). 

Flaking paint is treated by infusion of an adhesive in the areas where needed, followed by resetting the flakes on the substrate the softening of the paint needed to bend it back is effected through solvent action or heat. Losses can only be filled and inpainted. Inpainting may also be necessary when cracks become so wide as to seriously affect the visual appearance of the painting. 

Similarly, examples of barriers arising largely from simple steric hindrance can be found, as for instance in the hindered diphenyls.35 On the other hand there are many arguments suggesting that this is not the important force in ethane and similar molecules. It would be difficult to understand the relatively slow fall in barrier from ethane to methyl silane to methyl germane on a van der Waals repulsion basis. Furthermore, the small effect of substituting F, Cl, or Br on one end would also seem mysterious. The equilibrium orientation in propylene is opposite to the predictions of one of the quantitative van der Waals theories. Finally, the apparently small effect of bending back the C—H bonds is not in accord with either the electrostatic or van der Waals pictures. 

Removal of condensation is an important consideration. Water collecting in an elbow or other low point of the system can effectively block the pipe, and reduce or disable the system. Builders should strive to design a pipe system that will allow condensation to run back through the pipe to the subslab aggregate. This can be accomplished by ensuring that the pipe run is vertical to the entire distance from the basement to the exhaust. A completely vertical pipe run with no bends or elbows will also provide a pipe system with lower static pressure losses that will enhance the effectiveness of both active and passive systems. If elbows or a low point is incorporated into the... 

Often, users will choose to make their own modifications, and only when experiencing manufacturing and quality problems with the product will they go back to the reed switch manufacturer and let him carry out the desired modifications. In Figs 5.14 and 5.15, the proper approach for cutting and/or bending the reed switch is shown. The effect on the pull-in and drop-out characteristics of cutting and bending the reed switch will be explained in more detail later. 

One other effect that deals with the structure of the interface and how it affects electrochemical reaction rates can be mentioned. As explained in Cliapter 6, some ions (usually anions) chemisorb on the electrode, bending back their solvation sheaths so that the ion itself comes into contact with the electrode surface and forms valence bonds with it. Such effects are potential dependent, and since the adsorption will tend to block the electrode surface, it will change the dependence of log i on Aty assumed earlier [Eq. (7.7)]. Such effects are particularly important in organoelectrochemistiy (see Cliapter 11) where the reactants themselves may adsorb in contact with the electrode as a function of potential and complicate the theory of the dependence of the rate of reaction (or current density, i) on potential... 

In complexes of symmetrical fran-s-olefins where the positions of all four substituents have been determined, it is possible for one set of trans substituents to be bent back more than the other set. This twist of the CR2 groups about the C=C bond would not be obvious from an inspection of the a and /3 angles. This is true in compound XIX (Table I) where the CFs groups are bent back more than the F atoms 7 = 132(1)° and 120(1)° for F and CF3, respectively. It is difficult to ascribe this effect solely to either steric or electronic causes. It seems reasonable that certain groups bend back more for electronic reasons, but in this instance it is the bulkier group that is bent back more. It is not possible to predict on electronic grounds whether F or CF3 should bend back more. 

Most heat pipes are cylindrical in shape. However, they can be manufactured in a variety of shapes involving 90° bends, S-tum.s, or spirals. Iliey can also be made as a flat layer with a thickness of about 0.3 cm. Flat heat pipes are very suitable for cooling high-power-output (say, 50 W or greater) PCBs. In this case, flat heat pipes are attached directly to the back surface of the PCB, and they absorb and transfer the heat to the edge.s. Cooling fins are usually attached to (he condenser end of the heat pipe to improve its effectiveness and to eliminate a bottleneck in the path of heat flow from the components to the environment when the ultimate heat sink is the ambient air. 

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