Working Out the Kinks

There is no stronger evidence of a crazy understanding than the making too iarge a cataiog of things necessary. 

Fortunately, many kinks aren t that hard to untangle. A hundred-foot extension cord that you didn t take the trouble to wind up properly is something you can straighten out with a little diligence and a few expletives. But others are more abstract. In our fledgling program, for example, one problem was the many variations in performance scores on different tests, scheduled inconsistently and after varying amounts of practice. 

I spent a lot of time wrestling with that one. One day, I recalled an ingenious way of combining measurements developed by two researchers, Drs. Pincus and Hoagland, while studying hormonal function in schizophrenic patients. No single measure set schizophrenics apart from normal patients, so they cooked up a kind of statistical stew, using lymphocyte counts and potassium levels instead of carrots and potatoes. They called it the TRI (Total Response Index). 

When the statistieally sophisticated psychologists realized what I was doing, they had a field day pointing out my failings unjustified assumptions, violations of statistical theory and other mathematical crimes. They talked about ordinal scales versus ratio scales and scolded me for not using analysis of variance instead of Chi-square and Student s T tests of significance. 

I predicted vindication, but darned if the five charts he picked at random didn t prove to be less than convincing. The TRIs matched up only roughly with the doses. Henry said very little, but I got his message and elected to retreat to the safer ground of conventional statistics. In the end, estimates of effectiveness came out about the same, but the psychologists had at least won a minor victory. 

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Scenario A highly renowned culinary school wants to appeal to future chefs who might not be able to afford going to school full time for two years. It develops a hybrid course that features online instruction for the first and third semesters, with hands-on semesters at the school in between. Prior to launch, the school runs a pilot to work out the kinks in their V-Chef course, and to gather initial customer feedback. 

If you re beguiled by an Aquarius, prepare to meet more eccentrics than you thought existed outside of the Land of Oz. Aquarius collects them. Your mission is to strike the Water Bearer as irreplaceable and fascinating enough to add to the collection. There s no need to present yourself falsely or to iron out the kinks. On the contrary. Be independent (but available). Express your opinions. And be yourself — the more unorthodox, the better. A dozen roses No, no, no. An invitation to a midnight ramble through the meat-packing district That could work. 

Using model programs offers the advantage of efficiency. Installation can be accomplished relatively quickly, often with minimal investment of staff time. Since model programs evolve from the experience of others, many of their kinks have already been worked out, which can facilitate implementation. 

We were, however, still going through a learning period with respect to experimental efficiency. As previously enumerated, there were still many kinks to work out. Accordingly, until we upgraded our test environment and completed dose-response studies of the effects of each drug in a controlled clinical setting, we felt it... 

By deuterating particular parts of the molecules, these concepts can be extended to measure the mean orientation of particular parts of the hydrocarbon chains and it is thus possible to build up a picture of the occurrence of kinks in these chains and how these kinks develop with increasing temperature. For a further discussion of this technique, the reader is referred to the work by Silver [440] already referred to and original papers cited therein. A detailed discussion of this topic would be out of place in a general work of the kind offered here. 

All steam pots have one tube allowing steam in and have another allowing condensed water out. Be sure that neither tube kinks or plugs up. A constricted steam tube may burst due to steam pressure. A constricted drainage tube will cause the pot to fill up with water, which will halt the progress of your work. If the tube continuously kinks, replace it with a newer and/or heavier-walled tube. 

Ironically, the ZEV mandate was based on a mistake. The GM Impact that started it all was never intended by its designers as a model for a production car. Smith had just gotten carried away. Its designers had intended the Impact as a test bed for electric car technology—regenerative brakes, transmission, computerized controls—but that was supposed to be just step one. Once the kinks were worked out of the electrical systems, the EV1 was supposed to be upgraded to a plug-in hybrid. 

The field itself is of course the primary parameter that must be known. Experimentally it is the voltage between tip and screen that is determined. However, a fairly accurate value ( 15%) of the field a few atom spacings above the surface can be derived from the over-all shape of the emitter, by procedures already worked out for field electron microscopy (44 b). At a given atom site, a inicrofield value can then be estimated from the geometry. Thus for a hemispherical knob on a plane, the field is enhanced by a factor of 3, at a kink site on a crystal surface, the enhancement has been estimated at 1.8. This procedure yields microfields in fair agreement with those estimated from Eq. (49) without any polarization correction (78). Refinements are still in order, however, when dealing with gas adatoms. 

Attempts to determine experimentally the values of and Wm were carried out using various techniques internal friction [36,37], deformation under load pulse sequence [38], and TEM. There are very few internal friction experiments on semiconductors. The reason is the brittleness of these materials and the need to work at very low frequencies in order to get a relaxation peak at moderate temperatures. The direct observation of kink motion was realized by TEM, either by studying the relaxation of out-of-equilibrium dissociated dislocations [39], by in situ deformation [40], or by using forbidden reflections in the high-resolution mode [41,42]. These various experiments were analyzed within the framework of the kink-diffusion model of Hirth and Lothe [12], which does not take into account... 

Another possibility is to take into account the pH dependence for the process generating kink positions, so that a reaction order vqh between 1 and 2 is predicted. In any event, the kink-catalyst theory remains to be worked out. 

These are just a few issues of concern regarding the transition to lead-free solder. Many questions still remain. This is evident in the multitude of studies, experiments, workshops and conferences available focusing on reliability, inspection, rework, alloy selection, and exemptions, as well as labeling and materials declarations. As the deadline draws near, most of the kinks should be worked out. It seems most U.S. companies are taking the EU dates seriously. No one is shirking their duties, says NEDA s Martin. No one said, No big deal, they ll slip those dates. The best advice, adds Martin, is to prepare and keep your eyes on the EU s laws as each member state completes their laws. Companies can do things in anticipation, but it all trickles down and it seems that time will tell how lead-free plays out for the entire SMT supply chain. Until then, maybe we should still keep our eyes on the price of duct tape. 

Figure 11.6 illustrates the energy that must be supplied by thermal activation. The curve of ab vs. A shows the force that must be applied to the dislocation (per unit length) if it were forced to surmount the Peierls barrier in the manner just described in the absence of thermal activation. The quantity A is the area swept out by the double kink as it surmounts the barrier and is a measure of the forward motion of the double kink. A = 0 corresponds to the dislocation lying along an energy trough (minimum) as in Fig. 11.5a. A2 is the area swept out when maximum force must be supplied to drive the double kink. A4 is the area swept out when the saddle point has been reached and the barrier has been effectively surmounted. The area under the curve is then the total work that must be done by the applied stress to surmount the barrier in the absence of thermal activation. When the applied stress is a a (and too small to force the barrier), the swept-out area is A, and the energy that must be supplied by thermal activation is then the shaded area shown in Fig. 11.6. The activation energy is then...

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