An Ideal Study

A sketch of an exemplary study illustrates what should be contained in a benefit-cost analysis of mandatory passive restraints if it is to be useful  

The first independent attempt to estimate conventionally the benefits and costs of mandatory passive restraints was made by Richard Amould and Henry Grabowski. For the reduction in fatalities and injuries in crashes they use two sets of estimates. One set is based on a 1981 field team study of rural traffic accidents which shows, for example that fatalities are reduced by 34 percent by air bags and lap belts together, 32 percent by lap and shoulder belts together, 28 percent by passive belts, and 25 percent by air bags alone. The field study estimates are only appronmately one half of the NHTSA lab study estimates which is the other set. Arnould and Grabowski assume that 60 to 70 percent of occupants with passive belts would use them and that 0 to 20 percent of occupants with air bags would also use lap belts. Occupant protection is assumed to have no affect on chances of accidents. The 1 5 distribution of traffic accident injuries and the estimates of restraint effectiveness in crashes are used to calculate the fatalities and injuries prevented. 

Values of the estimated reductions in risk of death and injury were based on amounts which individuals implicitly reveal they are willing to pay for risk reduction. Citing a study by Martin Bailey they use a value of 300 for a risk reduction of. 001, or as it is sometimes expressed a value of lifesaving of 300,000, (1975 values). Adjustment for medical and legal cost externalities are made. A weighting scheme which expresses values of injuries ranging from critical to minor as a fraction of the value for a fatality. The estimates of the costs of passive belts and air bags are based on industry estimates and are approximately 50 and 225 respectively. 

In steady-state equilibrium the annual total social costs of passive belts are estimated to be from 0.5 to 1.0 billion dollars per year and the same type of costs of air bags are estimated to be from 2.5 to 6.5 billion dollars per year depending on which cost estimates are used. Comparable benefits are estimated to be from 2.1 to 5.5 billion dollars per year for passive belts and 3.6 to 6.4 billion dollars per year for air bags. Costs and benefits are expressed in 1975 dollars. For passive belts the estimated net benefits are positive for each case examined. For air bags, the net benefits are smaller and always negative for the better costs estimates. Arnould and Grabowski conclude that passive belts are a much more cost effective approach to occupant crash protection than air bags. 

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An ideal study approach attempts to clearly delineate a hypothesis and follow a carefully prescribed protocol. In addition, the investigator provides a clear reporting of the data and describes the analysis to support the conclusions. Listed below are some of the factors that EPA considers in its review of a study ... 

Our study of the physical and coloration characteristics of 18th century silks has to be classified as an ideal study. We were able to closely examine a wide cross-section of textiles for all the clues that they contain. This type of cooperation involving the question of provenance, which is so difficult to determine for textiles because design migration and readaptation are so prevalent, has produced a systematic method for an approach to the documentation of 18th century Chinese and Western painted and printed silks (Tables I and II). 

Botsford, L. W., Lawrence, C. A., Dever, E. P., Hastings, A., and Largier, J. (2003). Wind strength and biological productivity in upweUing systems An idealized study. Fish. Oceanogr. 12, 245-259. 

An ideal study of support effects requires model catalysts with metal particles that are identical in size and shape (so that only the support oxide varies). This is difficult to achieve for impregnated catalysts, but identical metal particles can be prepared via epitaxial model catalysts [36]. Well-faceted Rh nanocrystals were grown on a 100-cm area NaCl(OOl) thin film at 598 K. One half of a Rh/NaCl sample was covered with Al Oj, and the other half with TiO. The preparation of Rh particles for both Al Oj- and TiO -supported model catalysts in a single step prevents any differences in particle size, shape, and surface structure which could occur if the samples were prepared in separate experiments. Three model catalysts were prepared, with a mean Rh particle size of 7.8, 13.3, and 16.7 mn (the films were finally removed from the NaCl substrate by flotation in water). Activation was performed by O /H treatments, with the structural changes followed by TEM (Fig. 15.6). Oxidation was carried out in 1 bar O at 723 K prodncing an epitaxially grown rhodium oxide shell on a Rh core (cf Fig. 15.5e), whereas the hydrogen reduction temperature was varied. 

An ideal study would have to take into account all the characteristics of the problem outlined above. Such a study does not yet exist, and it might be quite difficult to include all the aspects into one empirically relevant quantitative model. In a more pragmatic line of thought, die following requirements seem to be especially important ... 

A comprehensive analysis of fern phylogenies, distribution ranges and available habitats is therefore needed to find out what shaped the modern ranges of our ferns. Here, we (1) summarise published studies that went in this direction and (2) combine these results with data of the fern flora of the isolated Azores archipelago, which is an ideal study system to test dispersal limitations. 

It is detemrined experimentally an early study was the work of Andrews on carbon dioxide [1], The exact fonn of the equation of state is unknown for most substances except in rather simple cases, e.g. a ID gas of hard rods. However, the ideal gas law P = pkT, where /r is Boltzmaim s constant, is obeyed even by real fluids at high temperature and low densities, and systematic deviations from this are expressed in tenns of the virial series ... 

The essentially non-destmetive nature of Rutherford backscattering spectrometry, combmed with the its ability to provide botli compositional and depth mfomiation, makes it an ideal analysis tool to study thm-film, solid-state reactions. In particular, the non-destmetive nature allows one to perfomi in situ RBS, thereby characterizing both the composition and thickness of fomied layers, without damaging the sample. Since only about two minutes of irradiation is needed to acquire a Rutherford backscattering spectmm, this may be done continuously to provide a real-time analysis of the reaction [6]. 

Within this contimiiim approach Calm and Flilliard [48] have studied the universal properties of interfaces. While their elegant scheme is applicable to arbitrary free-energy fiinctionals with a square gradient fomi we illustrate it here for the important special case of the Ginzburg-Landau fomi. For an ideally planar mterface the profile depends only on the distance z from the interfacial plane. In mean field approximation, the profile m(z) minimizes the free-energy fiinctional (B3.6.11). This yields the Euler-Lagrange equation... 

Let us first stress that the program of a benchmai k handling of the R-T effect, as presented in Table I, represents an idealization in none of the studies that have been published thus far has it been realized in all points. 

The important question, then, is not whether a substance is pure but whether a given sample is sufficiently pure for some intended purpose. That is, are the contaminants likely to interfere in the process or measurement that is to be studied. By suitable manipulation it is often possible to reduce levels of impurities to acceptable limits, but absolute purity is an ideal which, no matter how closely approached, can never be attained. A negative physical or chemical test indicates only that the amount of an impurity in a substance lies below a certain sensitivity level no test can demonstrate that a specified impurity is entirely al ent. 

For a given amplitude of the quasi-elastic release wave, the more the release wave approaches the ideal elastic-plastic response the greater the strength at pressure of the material. The lack of an ideally elastic-plastic release wave in copper appears to suggest a limited reversal component, however, this is much less than in the silicon bronze. Collectively, the differences in wave profiles between these two materials are consistent with a micro-structurally controlled Bauschinger component as supported by the shock-recovery results. Further study is required to quantify these findings and... 

My principal objective in Section 10.4 has been to underline the necessity for a drastic enhancement of a crucial experimental technology, the production of ultrahigh vacuum, as a precondition for the emergence of a new branch of science, and this enhancement was surveyed in the preceding Section. It would not be appropriate in this book to present a detailed account of surface science as it has developed, so 1 shall restrict myself to a few comments. The field has been neatly subdivided among chemists, physicists and materials scientists it is an ideal specimen of the kind of study which has flourished under the conditions of the interdisciplinary materials laboratories described in Chapter 1. 

The above measurements all rely on force and displacement data to evaluate adhesion and mechanical properties. As mentioned in the introduction, a very useful piece of information to have about a nanoscale contact would be its area (or radius). Since the scale of the contacts is below the optical limit, the techniques available are somewhat limited. Electrical resistance has been used in early contact studies on clean metal surfaces [62], but is limited to conducting interfaces. Recently, Enachescu et al. [63] used conductance measurements to examine adhesion in an ideally hard contact (diamond vs. tungsten carbide). In the limit of contact size below the electronic mean free path, but above that of quantized conductance, the contact area scales linearly with contact conductance. They used these measurements to demonstrate that friction was proportional to contact area, and the area vs. load data were best-fit to a DMT model. 

A practical method of predicting the molecular behavior within the flow system involves the RTD. A common experiment to test nonuniformities is the stimulus response experiment. A typical stimulus is a step-change in the concentration of some tracer material. The step-response is an instantaneous jump of a concentration to some new value, which is then maintained for an indefinite period. The tracer should be detectable and must not change or decompose as it passes through the mixer. Studies have shown that the flow characteristics of static mixers approach those of an ideal plug flow system. Figures 8-41 and 8-42, respectively, indicate the exit residence time distributions of the Kenics static mixer in comparison with other flow systems. 

Intermetallics also represent an ideal system for study of shock-induced solid state chemical synthesis processes. The materials are technologically important such that a large body of literature on their properties is available. Aluminides are a well known class of intermetallics, and nickel aluminides are of particular interest. Reactants of nickel and aluminum give a mixture with powders of significantly different shock impedances, which should lead to large differential particle velocities at constant pressure. Such localized motion should act to mix the reactants. The mixture also involves a low shock viscosity, deformable material, aluminum, with a harder, high shock viscosity material, nickel, which will not flow as well as the aluminum. 

An SWCNT a few microns long with electrical contacts deposited via nanolithography techniques is an ideal system to study single-molecule transistor effects, in which an electrode (Vga/e) close to the conducting CNT is used to modulate the conductance [33]. 

A computer program was developed based upon theoretical considerations. The results of a parameter study were used to compose a diagram (Figure 9.7) for use in determining initial velocity for vessels tilled with an ideal gas (Baker et al. 1978a and 1983). The scaled pressure P on the horizontal axis of Figure 9.7 is determined by... 

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