Pull-in effects

H. R. Brown. Chain mobihty and pull-out effects in lubrication and friction. Faraday Discuss Chem Sci 98 41-54, 1994. 

The damper and field windings each produce an effect on accelerating torque. The resistance of the damper winding is usually selected to produce its maximum torque during the first part of the starting period and a field-discharge resistor is selected so that the field-circuit torque peaks near pull-in speed. 

The decrease in atomic radius moving across the periodic table can be explained in a similar manner. Consider, for example, the third period, where electrons are being added to the third principal energy level. The added electrons should be relatively poor shields for each other because they are all at about the same distance from the nucleus. Only the ten core electrons in inner, filled levels (n = 1, n = 2) are expected to shield the outer electrons from the nucleus. This means that the charge felt by an outer electron, called the effective nuclear charge, should increase steadily with atomic number as we move across the period. As effective nuclear charge increases, the outermost electrons are pulled in more tightly, and atomic radius decreases. 

Ionic radius. Ionic radii do not change much in going across a transition row. The reason for this is essentially a balance of two effects (1) As nuclear charge increases across the row, the electrons would be pulled in, so the ions ought... 

It is normal practice to have screws double flighted under the feed section. This is mainly because a single flight, working in conjunction with the feed roll, does not effectively pull in the feed strip in a consistent manner. In some extruder constructions the double flight continues down the length of... 

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. 

Note the flow of positive holes in one direction is, in effect, a flow of electrons in the opposite direction. So, the p-n junction should still have the same orientation in (b) as in (a). Now the conduction electrons are pulled to the right and the positive holes to the left. Because there are very few conduction electrons in the p-type semiconductor and very few positive holes in the n-type semiconductor, there are very few carriers of electric charge across the p-n junction. Very little electric current flows. 

In the body of a liquid, intermolecular forces pull the molecules in all directions. At the surface of the liquid, the molecules pull down into the body of the liquid and from the sides. There are no molecules above the surface to pull in that direction. The effect of this unequal attraction is that the liquid tries to minimize its surface area. The minimum surface area for a given quantity of matter is a sphere. In a large pool of liquid, where sphere formation is not possible, the surface behaves as if it had a thin stretched elastic membrane or skin over it. The surface tension is the resistance of a liquid to an increase in its surface area. It requires force to break the attractive forces at the surface. The greater the intermolecular force, the greater the surface tension. Polar liquids, especially those that utilize hydrogen bonding, have a much higher surface tension than nonpolar liquids. 

The alveolar tension of other anesthetic gases also rises more rapidly (second gas effect) when an anesthetic such as N2O is present in high concentration. These gases are also subject to the increased inflow (pulling in of fresh gases) as N2O is taken up into the blood. 

Surface tension is caused by hydrogen bonds. As shown in Figure 8.14, beneath the surface, each water molecule is attracted in every direction by neighboring molecules, with the result that there is no tendency to be pulled in any preferred direction. A water molecule on the surface, however, is pulled only by neighbors to each side and those below there is no pull upward. The combined effect of these molecular attractions is thus to pull the molecule from the surface into the liquid. This tendency to pull surface mol-... 

As you can see in the above figure, some fibres are somewhat pulled out of the matrix when a crack grows this occurs under the influence of prevailing forces. This is called the fibre pull-out effect. 

The effect of a non-vanishing potential on the radial function is illustrated in Fig. 7.4 for the example of a repulsive potential of rectangular shape. It can be seen that the selected s-wave radial function RK0(r) strongly differs in the region of potential from the corresponding spherical Bessel function j0(fcr). However, far away from the influence of the potential, the function Rk0(t) behaves like the asymptotic spherical Bessel function j0(Kr), except that it is shifted in phase. A repulsive potential pushes out, and an attractive potential pulls in the radial functions RKf(r) as compared to j/xr). This behaviour is expressed in the asymptotic forms of these radial functions (for the general case with ( and an attractive potential) ... 

In high-rise buildings in the winter when the cold air on the outside is heavier than the conditioned air on the inside, the chimney effect tends to pull in ambient air at ground elevation, and this cold air adds an additional load to the building s heating system. Eliminating the chimney effect can lower the operating cost by approximately 10%. 

The strength of this attraction is based on two factors the distance from the nucleus to the outermost electrons, and the valence electron pattern. The distance factor is a function of the fact that the closer the nucleus is to the outer electrons, the greater the power of the nucleus in pulling in other electrons. This is similar to the observation that a magnet works best when close to an object. As the valence electron pattern approaches the noble gas valence electron pattern, the more effective the element is at attracting electrons. Noble gases have virtually no electronegativity, as they rarely react. 

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