Recourses

The level of injector fouling is most often illustrated in terms of residual flow (RF) expressed as a percentage of the flow under new conditions for a given needle lift. An RF on the order of 20% for a lift of 0.1 mm is a good compromise. This level may not be achieved with certain aromatic or naphthenic diesel fuels. The best recourse is then detergent additive addition. 

Eddy-current non-destructive evaluation is widely used in the aerospace and nuclear power industries for the detection and characterisation of defects in metal components. The ability to predict the probe response to various types of defect is highly valuable since it enables the influence of particular parameters to be studied without recourse to costly and time consuming experiments. The solution of forward problems is also essential in the process of inverting experimental data. 

It would be tlierefore thus easy to obtain in real time, on computer, tlie image of a long standard defect that is to even to produce the impedance variation observed. It would be thus possible to realize the control by absolute measures and to avoid the recourse to standard defects. 

There is of course no requirement to confine the slice selection to the z-gradient. The gradients may be used in any combination and an image plane selected in any orientation without recourse to rotating the sample. 

For small molecules, the accuracy of solutions to the Schrtidinger equation competes with the accuracy of experimental results. However, these accurate a i initw calculations require enormous com putation an d are on ly suitable for the molecular system s with small or medium size. Ah initio calculations for very large molecules are beyond the realm of current computers, so HyperChern also supports sern i-em p irical quantum meclian ics m eth ods. Sem i-em pirical approximate solutions are appropriate and allow extensive cliem ical exploration, Th e in accuracy of the approxirn ation s made in semi-empirical methods is offset to a degree by recourse to experimental data in defining the parameters of the method. 

When the correct solvent for recrystallisation is not known a procedure similar to that given on pp. 15-16 should be followed, but on the semi-micro scale not more than 10 mg. of the solid should be placed in the tapered-end test-tube (Fig. 29(B)) and about o i ml. of the solvent should be added from the calibrated dropping-pipette (Fig. 30(B)). If the compound dissolves readily in the cold, the solvent is unsuitable, but the solution should not be discarded. [In this case recourse should be had to the use of mixed solvents (p. 18). For example if the substance is very soluble in ethanol, water should be added from a calibrated pipette with shaking to determine whether crystallisation will now take place, indicated by a cloudiness or by the separation of solid.]... 

This new edition, the hfth under the aegis of the present editor, remains the one-volume source of factual information for chemists, both professionals and students—the hrst place in which to look it up on the spot. The aim is to provide sufficient data to satisfy all one s general needs without recourse to other reference sources. A user will hnd this volume of value as a time-saver because of the many tables of numerical data which have been especially compiled. 

It must always be borne in mind that when capillary condensation takes place during the course of isotherm determination, the pore walls are already covered with an adsorbed him, having a thickness t determined by the value of the relative pressure (cf. Chapter 2). Thus capillary condensation occurs not directly in the pore itself but rather in the inner core (Fig. 3.7). Consequently the Kelvin equation leads in the first instance to values of the core size rather than the pore size. The conversion of an r value to a pore size involves recourse to a model of pore shape, and also a knowledge of the angle of contact 0 between the capillary condensate and the adsorbed film on the walls. The involvement of 0 may be appreciated by consideration... 

Both (i) and (ii) necessitate recourse to a model of pore shape. By far the commonest, chosen on grounds of simplicity, is the cylinder but the slit model is being increasingly used where the primary particles are plate-like, and the model where the pore is the cavity between touching spheres is beginning to receive attention. 

The computation of mesopore size distribution is valid only if the isotherm is of Type IV. In view of the uncertainties inherent in the application of the Kelvin equation and the complexity of most pore systems, little is to be gained by recourse to an elaborate method of computation, and for most practical purposes the Roberts method (or an analogous procedure) is adequate—particularly in comparative studies. The decision as to which branch of the hysteresis loop to use in the calculation remains largely arbitrary. If the desorption branch is adopted (as appears to be favoured by most workers), it needs to be recognized that neither a Type B nor a Type E hysteresis loop is likely to yield a reliable estimate of pore size distribution, even for comparative purposes. 

Equilibrium Theory. The general features of the dynamic behavior may be understood without recourse to detailed calculations since the overall pattern of the response is governed by the form of the equiUbrium relationship rather than by kinetics. Kinetic limitations may modify the form of the concentration profile but they do not change the general pattern. To illustrate the different types of transition, consider the simplest case an isothermal system with plug flow involving a single adsorbable species present at low concentration in an inert carrier, for which equation 30 reduces to... 

Usually an analytical solution to the equation of motion cannot be found recourse must... 

Two-Step Process. The significant advantage of the two-step process is that it only requkes commercial-grade methyl formate and ammonia. Thus the cmde product leaving the reactor comprises, in addition to excess starting materials, only low boiling substances, which are easily separated off by distillation. The formamide obtained is of sufficient purity to meet all quaUty requkements without recourse to the costiy overhead distillation that is necessary after the dkect synthesis from carbon monoxide and ammonia. 

Municipal Solid Waste. In the eady 1990s, the need to dispose of municipal soHd waste (MSW) ia U.S. cities has created a biofuels industry because there is Htde or no other recourse (107). Landfills and garbage dumps are being phased out ia many communities. Combustion of MSW, ie, mass-bum systems, and RDF, ie, refuse-derived fuel, has become an estabhshed waste disposal—energy recovery industry. 

Data compilations, the first recourse for an engineering calculation requiring physical property or parameter data, are often incomplete or do not contain data within the appropriate range of temperature or pressure (6—9). For this reason, correlation and estimation methods play an important role in apphed thermodynamics. 

Generalized Correlations. Generalized correlations are often the only recourse when a property value cannot be determined from empirical correlations or by other means. Several powerful correlating techniques fall under this category, including the principle of corresponding states (3,17), reduced property models (1), and the Polanyi-type characteristic curve for microporous adsorbents (14). 

A modified definition of resonance energy has been introduced by Dewar (66T(S8)75, 69JA6321) in which the reference point is the corresponding open-chain polyene. In principle this overcomes the difficulties inherent in comparing observed stability with that of an idealized molecule with pure single and double bonds, as thermochemical data for the reference acyclic polyenes are capable of direct experimental determination. In practice, as the required data were not available, recourse was made to theoretical calculations using a semiempirical SCF-MO method. The pertinent Dewar Resonance Energies are listed in Table 30. 

Additives can alter the rate of wet ball milling by changing the slurry viscosity or by altering the location of particles with respect to the balls. These effects are discussed under Tumbhng Mills. In conclusion, there is still no theoretical way to select the most effective additive. Empirical investigation, guided by the principles discussed earlier, is the only recourse. There are a number of commercially available grinding aids that may be tried. Also, a Idt of 450 surfactants that can be used for systematic trials (Model SU-450, Chem Service... 

Local Failure The penetration or perforation of most industrial targets cannot be assessed using theoretical analysis methods, and recourse is made to using one of the many empirical equations. In using the equations, it is essential that the parameters of the empirical equation embrace the conditions of the actual fragment. 

In both applications described above agreement is good, providing strong support for an energy balance theory of fragmentation. Note in particular that no recourse to an inherent fracture flaw distribution was needed. 

The same curve may be used to represent a turbine specified for a greater power than needed, which would be the upper curve, when all that was needed was the lower curve. Again, the same effect, except with no recourse other than poor operation. 

Capability to control and extinguish the anticipated fire condition without recourse to outside assistance (unless planned for). 

It is hoped that the improvements will help to achieve die objectives for which die text was originally conceived, i.e. to summarize in relatively basic terms die hazards associated with chemicals and how the ensuing risks can be controlled, and to provide sufficient detailed information to supplement that obtainable from suppliers, government publications, trade associations, and computerized data banks where recourse to specialized textbooks may be premature, difficult or unnecessary. 

Representativeness can be examined from two aspects statistical and deterministic. Any statistical test of representativeness is lacking becau.se many histories are needed for statistical significance. In the absence of this, PSAs use statistical methods to synthesize data to represent the equipment, operation, and maintenance. How well this represents the plant being modeled is not known. Deterministic representativeness can be answered by full-scale tests on like equipment. Such is the responsibility of the NSSS vendor, but for economic reasons, recourse to simplillcd and scaled models is often necessary. System success criteria for a PSA may be taken from the FSAR which may have a conservative bias for licensing. Realism is more expensive than conservatism. 

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