Recording devices

The pH meter usually is coupled to a data recording device and often to a pneumatic or electric controller. The controller governs the addition of reagent so that the pH of the process stream is maintained at the desired level. 

Dry-heat sterilization is generally conducted at 160—170°C for >2 h. Specific exposures are dictated by the bioburden concentration and the temperature tolerance of the products under sterilization. At considerably higher temperatures, the required exposure times are much shorter. The effectiveness of any cycle type must be tested. For dry-heat sterilization, forced-air-type ovens are usually specified for better temperature distribution. Temperature-recording devices are recommended. 

A coal measuring and recording device for stoker fired or PF fired boilers. 

In transient measurements one must record rapidfy changing currents or potentials. In the past, cathode-ray oscilloscopes have been used for this purpose (at present, improved recording devices or computers are used as well), hence the term oscillographic polarography (or oscillographic voltammetry). This term is unfortunate since it reflects only the device used to record the results, rather than the essential features of the method used for the measurements. 

Storage chambers should be validated with respect to their ability to maintain the desired conditions, and, if so equipped, the ability to sound an alarm if a mechanical or electrical failure causes the temperature to deviate from preestabilished limits. They should also be equipped with recording devices, which will provide a continuous and permanent history of their operation. Logbooks should be maintained and frequent readings or mercury-in-glass, National Institute of Science and Technology traceable thermometers recorded. 

The method can successfully be used in analyses of impurities in metals and alloys, for estimation of minor elements in monomolecular films of oxide layers of Fe-Cr-Ni alloys, for detection of metal impurities in environmental pollution, for studying the depression of high-grade semiconducting materials and for analysis of the corrosion products of contact junction diodes used in microelectronic circuits. Much sophistication is desirable on the instrumental side so as to incorporate an automatic recording device to make an FR polarograph suitable for wider applications and common use. 

The main sources of broadening are the solute dispersion in the connecting tubes, the effective working volume of the detector and the dynamics of the sensor, of the electronic circuitry and of the recording device. 

There has been a recent upsurge of interest in electrochemical deposition, due mainly to three new technologies (1) metal deposition for the fabrication of integrated circuits, (2) deposition for magnetic recording devices (heads, disks), and (3) deposition of multilayer structures. 

The most important modern applications of iron oxides are as ores for the iron and steel industry and as pigments (Heine and Volz, 1993). Fe oxides are also used extensively as magnetic pigments in electronic recording devices and as catalysts in industrially important syntheses. Other minor, but still important applications are listed in Table 19.1 and are discussed in the following sections. 

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