The Program Criticized

Because the thrust of the book has been largely centered around questions of how best to construct models, it is sure that if the reader has made it this far, then he or she might have the sense that at every turn I have made it sound as though nearly all models are effective theories . Part of this enthusiasm draws from my support of a statement of Goldenfeld (1992) in a different context who notes 

In my opinion, the renormalization group is one of the more profound discoveries in science, because it is a theory about theories. It has enabled physicists to become self-conscious about the way in which they constmct physical theories, so that Dirac s dictum that we should seek the most beautiful or simplest equations acquires a meaningful and quantifiable aspect. 

Indeed, the advent of the computer has placed a new class of demands on our theories. Because of the inevitable sense that pure brute force approaches are unacceptable, this has spawned the types of self-conscious efforts at theory building alluded to above, but now with the aim being a new kind of simplicity related to our ability to formulate tractable computational models of complex phenomena. 

Perhaps the most damning criticism that can be leveled against the emergence of computational materials science is the difficulty of putting these computations in direct contact with experiments themselves. Unfortunately, much of the direct 

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Early in the program, critical components (e.g.,the turbomolecular pump) and circuit boards were tested for their ability to survive neutron and gamma irradiation rates and doses similar to those that would be received from exposure to the detonation of a tactical nuclear device. All components were powered up at the start of the gamma irradiation tests but not during the neutron irradiation tests. Circuit boards were protected by circumvention circuits that powered down critical circuits in 10 to lOOps upon detecting radiation. All components survived the nuclear radiation tests. This unusual performance was noted with positive commendations by the staff at the White Sands Missile Range, where the tests were performed. Tests of the fully integrated CBMS II system, installed in a reconnaissance vehicle, will be conducted in the future. 

Critical parameters verification of the programmed critical parameters against specification (e.g., program cycle parameters for time, temperature, pressure, alarm). 

Near top speed, a fan may operate at a speed that is near or above the natural frequency of the wheel and shaft. Under such conditions, the fan can vibrate badly even when the wheel is clean and properly balanced. Whereas manufacturers often do not check the natural frequency of the wheel and shaft ia standard designs, many have suitable computer programs for such calculations. Frequency calculations should be made on large high speed fans. The first critical wheel and shaft speed of a fan that is subject to wheel deposits or out-of-balance wear should be about 25—50% above the normal operating speed. 

Jons. Amelin [Theory of Fog Condensation, Israel Program for Scientific Translations, Jerusalem, (1967)] reports that ordinary air contains even higher concentrations of ions. These ions also reduce the required critical supersaturation, but by only about 10 to 20 percent, unless multiple charges are present. 

The choice of variables remaining with the operator, as stated before, is restricted and is usually confined to the selection of the phase system. Preliminary experiments must be carried out to identify the best phase system to be used for the particular analysis under consideration. The best phase system will be that which provides the greatest separation ratio for the critical pair of solutes and, at the same time, ensures a minimum value for the capacity factor of the last eluted solute. Unfortunately, at this time, theories that predict the optimum solvent system that will effect a particular separation are largely empirical and those that are available can be very approximate, to say the least. Nevertheless, there are commercially available experimental routines that help in the selection of the best phase system for LC analyses, the results from which can be evaluated by supporting computer software. The program may then suggest further routines based on the initial results and, by an iterative procedure, eventually provides an optimum phase system as defined by the computer software. 

The extent to which planned tasks are being completed on time The degree of slippage or slack in the program The critical paths and changes in criticality Lead times and effect of changes on advanced procurement Resource utilization Spend versus budget Estimated spend to completion... 

Tlic heat duty is best calculated with a process simulation program hi will account for phase changes as the fluid passes throiigli ilic ctioke. It will balance the enthalpies and accurately predict the change m tcnipcrature across the choke. Heat duty should be checked for vanoits combinations of inlet temperature, pressure, flow rate, and outlet temper ature and pressure, so as to determine the most critical combination. 

Reference or baseline data sets should be acquired for each machine-train or process system to be included in a predictive maintenance program when the machine is installed or after the first scheduled maintenance once the program is established. These data sets can be used as a reference or comparison for all future measurements. However, such data sets must be representative of the normal operating condition of each machine-train. Three criteria are critical to the proper use of baseline comparisons reset after maintenance, proper identification, and process envelope. 

The added capability of calculating unknown values based on measured inputs will greatly enhance the system capabilities. For example, the neither fouling factor nor efficiency of a heat exchanger can be directly measured. A predictive maintenance system that can automatically calculate these values based on the measured flow, pressure and temperature data would enable the program to automatically trend, log and alarm deviations in these unknown, critical parameters. 

The data logger or microprocessor selected by your predictive maintenance program is critical to the success of the program. There is a wide variety of systems on the market that range from handheld overall value meters to advanced analyzers that can provide an almost unlimited amount of data. The key selection parameters for a data acquisition instrument should include the expertise required to operate, accuracy of data, type of data, and manpower required to meet the program demands. 

The accountability expected of the predictive maintenance group is another factor that is critical to program effectiveness. If measures of program effectiveness are not established, neither management nor program personnel can determine if the program s potential is being achieved. 

The type of transducers and data acquisition techniques that you will use for the program is the final critical factor that can determine the success or failure of your program. Their accuracy, proper application and mounting will determine whether valid data will be collected. 

As the overall fabricating tolerance is analyzed into the sources of its variation components, the potential advantage of analytical programs comes into play with their ability to efficiently process all these factors. All the empirical tolerance ranges for each tooling method and inspection method are stored in data files for easy retrieval. For each critical dimension the program sums all the com-... 

Critical ( -values for p - 0.05 are available. " - In lieu of using these tables, the calculated -values can be divided by the appropriate Student s t(f, 0.05) and V2 and compared to the reduced critical -vdues (see Table 1.12), and data file QRED TBL.dat. A reduced -value that is smaller than the appropriate critical value signals that the tested means belong to the same population. A fully worked example is found in Chapter 4, Process Validation. Data file MOISTURE.dat used with program MULTI gives a good idea of how this concept is applied. MULTI uses Table 1.12 to interpolate the cutoff point for p = 0.05. With little risk of error, this table can also be used fo = 0.025 and 0.1 (divide q by t(/, 0.025) /2 respectively t f, 0.1) V 2, as appropriate. 

For large systems, the computation of the energy can require 98% or more of the total computational effort, and within the energy computation, the pair interaction energy (van der Waals and electrostatic terms) can represent more than 90% of the total effort. For this reason, the aspects of the program that deal with the generation of the nonbond list and the computation of the nonbond energy are of critical importance. 

The following steps, implemented by a computer program written in C, generate the smoothed, recommended values. Input to the program consists of the set of observed density values, temperatures, estimated uncertainties, critical constants and values of certain parameters used by the program. 

How clean the data must be depends on the importance of the data. Critical analysis variables must be clean, so this is where the site and data management groups should focus their resources. If the data are dirty at the time of statistical analysis, many inefficient and costly workarounds may need to be applied in the statistical programming, and the quality of the data analysis could suffer. However, if a variable is not important to the statistical analysis, then it is better to save the expense of cleaning that variable. 

The field of these very important chemicals covers a very broad scope. An organized consideration of all phases of the problem is needed in developing a research program. From this the most critical research needs should be selected and emphasized. The following outline presents one type of an organized picture of the breadth and scope of the problem, and the variety of research and educational needs. Chemistry plays a major role in this work. 

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