High precision

The different techniques of NDT were applied to evaluate the method allowing to give an optimal spectrum so that the interpretation can be done easily. In addition, and for the purpose of the defects quantification, we have done an optimization on the magnetic powders, colored and fluorescent, by applying magnetic powders of variable dimensions. This will enable us to estimate defects with a high precision. 

Measurement of the conductivity can be carried out to high precision with specially designed cells. In practice, tiiese cells are calibrated by first measuring the conductance of an accurately known standard, and then introducing the sample under study. Conductances are usually measured at about 1 kHz AC rather than with DC voltages in order to avoid complications arismg from electrolysis at anode and cathode [8]. 

Furthermore, it must be remembered that highly disperse materials are, from their very nature, difficult to prepare with exactly reproducible surface properties, in respect of either the extent of the surface or the nature of the surface itself. Consequently, highly precise values of the absolute area of individual samples, even if attainable by some method as yet undeveloped, would be of little more value in practice than the BET specific surface, calculated from carefully measured isotherms. 

Guenther, W. B. Supertitrations High-Precision Methods, /. Chem. Educ. 1988, 65, 1097-1098. 

Identification of a molecule known in the laboratory is usually unambiguous because of the uniqueness of the highly precise transition frequencies. However, before frequencies detected in the interstellar medium can be compared with laboratory frequencies they must be corrected for the Doppler effect (see Section 2.3.2) due to the motion of the clouds. In Sagittarius B2 the molecules are found to be travelling fairly uniformly with a velocity of... 

Scales win always perform better in a temperature-controlled environment this is particularly important for high precision balances. Those designed to automatically recaHbrate as conditions change will perform better in less-than-ideal conditions. 

Chemical analysis of the metal can serve various purposes. For the determination of the metal-alloy composition, a variety of techniques has been used. In the past, wet-chemical analysis was often employed, but the significant size of the sample needed was a primary drawback. Nondestmctive, energy-dispersive x-ray fluorescence spectrometry is often used when no high precision is needed. However, this technique only allows a surface analysis, and significant surface phenomena such as preferential enrichments and depletions, which often occur in objects having a burial history, can cause serious errors. For more precise quantitative analyses samples have to be removed from below the surface to be analyzed by means of atomic absorption (82), spectrographic techniques (78,83), etc. 

Eor processing after sintering, in the least expensive method for sintered PTEE tape or sheet, a large billet is skived on a lathe after it has been sintered and cooled. High precision articles are machined from ram-extmded rods. 

Electronic-Grade MMCs. Metal-matrix composites can be tailored to have optimal thermal and physical properties to meet requirements of electronic packaging systems, eg, cotes, substrates, carriers, and housings. A controUed thermal expansion space tmss, ie, one having a high precision dimensional tolerance in space environment, was developed from a carbon fiber (pitch-based)/Al composite. Continuous boron fiber-reinforced aluminum composites made by diffusion bonding have been used as heat sinks in chip carrier multilayer boards. 

The disk refiner, a newer development used for fine paper grades, includes one or two rotary disks and two or four working surfaces. The surfaces are pressed together uniformly by hydraulic pressure and guided by high precision, heavy-duty bearing systems. Stock usuaUy is fed through the center of one plate and leaves between the plates at their circumferences. 

AH of these technologies require careful attention to the film transport mechanism to avoid imaging defects. The sizes of the features produced on the film, typicaHy resolution of 1000 spots/cm or greater, and the accuracy of spot placement both require high precision equipment. Even minute misplacements of spots can produce objectionable visible artifacts. 

Applications. Molecules couple to an electromagnetic field through their electric dipoles, so only those having a permanent dipole moment exhibit significant rotational spectra. For such species, microwave spectroscopy yields highly precise moments of inertia and details of centrifugal... 

Cesium metal is used for time standards based on the natural vibration of the Cs atom, which oscillates 9,192,631,770 times per second, and in high precision oscillators to synchronize fiber optic telecommunication. 

Theoretical equation forms may be derived from either kinetic theory or statistical mechanics. However, empirical and semitheoretical equations of state have had the greatest success in representing data with high precision over a wide range of conditions (1). At present, theoretical equations are more limited in range of appHcation than empirical equations. There are several excellent references available on the appHcation and development of equations of state (2,3,18,21). 

FIG. 21-38 Typical high-precision hqiiid filling and weighing system for packaging 208-L (55-gal) steel drums and similar smaller containers. (Couttesy of H. F. Henderson Industries, Inc., Caldwell, NJ.)... 

The rotor flux-oriented control is more popular among different manufacturers to achieve high precision of speed control in an induction machine. With this technology (any of the three methods noted above), it is now possible to obtain a high performance of the machine, i.e. torque up to 100% of Tr at speeds down to zero. 

Precision testing or laboratory testing CTs Laboratory and lest work in conjunction with high precision indicating instruments, integrating meters and also for the testing of industrial CTs Precision industrial meters (indicating instruments and recorders)... 

The heart of these couplings is the flexing disc it is manufactured from vacuum-degassed alloy steel, forged with a radial-grain orientation, and has a contoured profile machined on high-precision equipment. 

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