Instrument definition

The temperature compensator on a pH meter varies the instrument definition of a pH unit from 54.20 mV at 0°C to perhaps 66.10 mV at 60°C. This permits one to measure the pH of the sample (and reference buffer standard) at its actual temperature and thus avoid error due to dissociation equilibria and to junction potentials which have significant temperature coefficients. 

Fig. 2.3. Absorbance as a function of optical density for selected shock tube investigations employing OH electronic absorption spectrometry. The unmarked curve represents the semi-empirical relationship derived in Reference 37, evaluated at a pressure (5 1 atm) and temperature (1520 K) typical of recombination experiments in an argon diluent. Tlie curves labelled 6 1, 3 1 and 1 3 were empirically determined over a selected range of recombination pressures and temperatures for mixtures dilute in argon with those particular initial H2/O2 ratios (Reference 32). The curve identified by HJ (Reference 24) was empirically determined in a 1 % Hg-l % 02-98 % Ar mixture at 1300 K for a selected range of pressures. The cross-hatched area represents the approximate range of absorbances and optical densities observed with an atomic bismuth line source (Reference 41). Also shown are the line HH derived from photographic spectroscopy using instrumental definition of absorption line centres on a continuum (Reference 48), and a solid circle (beyond the range of the abscissa) denoting the photoelectric absorbance reported in Reference 47 for a continuum source at an optical density of 750 x 10" moles liter cm.

Ordnance removed without changing its orientation and handed to EOD Ordnance not touched by metal instruments Definitive procedure completed in operating theatre... 

Accuracy and Repeatability Definitions of terminology pertaining to process measurements can be obtained from standard S5I.I from the International Society of Measurment and Control (ISA) and standard RC20-II from the Scientific Apparatus Manufac turers Association (SAMA), both of which are updated periodically. An appreciation of accuracy and repeatability is especially important. Some apphcations depend on the accuracy of the instrument, but other apphcations depend on repeatability. Excellent accuracy imphes excellent repeatabihty however, an instrument can have poor accuracy but excellent repeatability. In some apphcations, this is acceptable, as discussed below. 

The flow capacity of the transducer can be increased bv adding a booster relav like the one shown in Fig, 8-7.3/ , The flow capacity of the booster relav is nominally fiftv to one hundred times that of the nozzle amplifier shown in Fig, 8-7.3 3 and makes the combined trans-diicer/booster suitably responsive to operate pneumatic actuators. This type of transducer is stable into all sizes of load volumes and produces measured accuracy (see Instrument Society of America [ISA]-S5l, 1-1979, Process Instrumentation Terminology for the definition of measured accuracy) of 0,5 percent to 1,0 percent of span. 

Direct acting indicating analogue electrical measuring instruments and their accessories Definitions and general requirements 1248-1 to 9 BS 89-1/1990 ... 

The easiest thing to do is to get the pump curve from the manufacturer because it has the NPSHr listed at different flows. Nowadays, you can get the pump curve on the Internet with an e-mail to the manufacturer, you can send a fax, or request the curve in the mail or with a local call to the pump representative or distributor. If you wanted to verify the NPSHr on your pump, you ll need a complete set of instrumentation a barometer gauge, compound pressure gauges corrected to the centerline of the pump, a flow meter, a velocity meter, and a thermometer. Definitely, it s easier to get the curve from your supplier. 

Wlien denoting instrumentation it is important that definitions be understood clearly. Terms for instruments and controls most often included on P 1 diagrams are given below ... 

The time difference (delay) between the measured quantity and the measurement result is called the inertial error. A definition- is the error due to iner tia (mechanical, thermal, etc.) of the parts of a measuring instrument. In ventilation equipment the critical component in the measuring chain, from the dynamic point of view, is often the sensor or the measuring transducer (probe). 

In spectrophotometric analysis a source of radiation is used that extends into the ultraviolet region of the spectrum. From this, definite wavelengths of radiation are chosen possessing a bandwidth of less than 1 nm. This process necessitates the use of a more complicated and consequently more expensive instrument. The instrument employed for this purpose is a spectrophotometer. 

X-ray spectral analysis, schematic diagrams of instruments for, 124, 125 X-ray spectrograph, curved-crystal, of Adler and Axelrod, 206, 207 definition, 124, 125 desirable conditions for, 162 estimated losses in, 124, 126, 127 General Electric XRD-5 D/S, 249-252 Industrial X-ray Quantometer, of Applied Research Laboratories, 256, 257... 

Microscopy. A broad definition of microscopy is the observation and measurement of optical parameters with any instrument that uses energy sources such as photons, electrons or X-rays to... 

Today, modern instrumentation provides much more direct evidence of atoms (Fig. B.3). There is no longer any doubt that atoms exist and that they are the units that make up the elements. In fact, chemists use the existence of atoms as the definition of an element an element is a substance composed of only one kind of atom. By 2006, 111 elements had been discovered or created but in some cases in only very small amounts. For instance, when element 110 was made, only two atoms were produced, and even they lasted for only a tiny fraction of a second before disintegrating. 

Definition and Uses of Standards. In the context of this paper, the term "standard" denotes a well-characterized material for which a physical parameter or concentration of chemical constituent has been determined with a known precision and accuracy. These standards can be used to check or determine (a) instrumental parameters such as wavelength accuracy, detection-system spectral responsivity, and stability (b) the instrument response to specific fluorescent species and (c) the accuracy of measurements made by specific Instruments or measurement procedures (assess whether the analytical measurement process is in statistical control and whether it exhibits bias). Once the luminescence instrumentation has been calibrated, it can be used to measure the luminescence characteristics of chemical systems, including corrected excitation and emission spectra, quantum yields, decay times, emission anisotropies, energy transfer, and, with appropriate standards, the concentrations of chemical constituents in complex S2unples. 

The simple situation The analytical method uses an instrument that provides an immediate readout of the definitive result, for example... 

We have described two highly Instrumented, data-logged and versatile pilot reactors which Integrate Into a rigorous scale-up regime. This Is necessitated by our highly complex products and the precise definition the computer-controlled full-scale plant can exploit. 

A fully automated instrumental procedure has been developed for analyzing residual corrosion inhibitors in production waters in the field. The method uses ultraviolet (UV) and fluorescence spectrophotometric techniques to characterize different types of corrosion inhibitors. Laboratory evaluations showed that fluorescence is more suitable for field application because errors from high salinity, contamination, and matrix effect are minimized in fluorescence analysis. Comparison of the automated fluorescence technique with the classic extraction-dye transfer technique showed definite advantages of the former with respect to ease, speed, accuracy, and precision [1658],... 

An extremely wide variety of analytical methods are used by RM producers and developers in the certification of RMs for inorganic elemental content. These methods range from the classical, through current instrument based methods to highly specialized definitive methods. 

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