Instrumentation portability

In TL, the light emission induced in the mineral or ceramics sample heated up to 500° C is measured by means of a photomultiplier detector. In addition to laboratory instrumentation, portable gamma spectrometers have been used when circumstances make sampling impractical. 

EC detection is a promising alternative for capillary electrophoresis microchips due to its inherent characteristics, allowing a proper miniaturisation of the devices and compatibility with the fabrication processes, in case of an integrated detection. Moreover, the low cost associated permit the employment of disposable elements. As the EC event occurs on the surface of electrodes and the decrease in size usually results in new advantages (see Chapter 32), the possibilities of incorporating EC detectors are broad. The simplicity of the required instrumentation, portable in many cases, suit well with the scaling-down trend. Moreover, as the sample volume in conventional micro-channel devices is less than 1 nL, a very highly sensitive detector should be constructed to analyse even modest concentrations of sample solutions. Since sensitivity is one of the accepted characteristics of EC detection EC-CE microchips approach to the ideal analytical devices. 

For the practical implementation of the above mentioned facts, the portable electronic digital coercive force meter with self-contained power supply, attached converter and closed type magnetic core. Instrument error is 5 %. ... 

The war itself also drove the development of improved and miniaturised electronic components for creating oscillators and amplifiers and, ultimately, semiconductors, which made practical the electronic systems needed in portable eddy current test instruments. The refinement of those systems continues to the present day and advances continue to be triggered by performance improvements of components and systems. In the same way that today s pocket calculator outperforms the large, hot room full of intercormected thermionic valves that I first saw in the 50 s, so it is with eddy current instrumentation. Today s handheld eddy current inspection instrument is a powerful tool which has the capability needed in a crack detector, corrosion detector, metal sorter, conductivity meter, coating thickness meter and so on. 

The contribution that Hocking wished to make was to refine the sensor system and the instrumentation paekage so as to be able to incorporate the necessary functionality within a lightweight portable battery operated instrument. This implied a lower power level and very low-noise instrumentation. We aimed also for a low cost instrument able to operate for several hours from fully charged batteries and able to operate at a pull speed of 500mm/second. 

Portable Eddy Curent Non-Destructive Testing Instrument. 

The modern Russian MIA flaw detectors use pulse version of the method [1-3], which peirnits to produce very portable (0.7 - 1.5 kg) and simple instruments, convenient especially for in-service testing. The objects to be tested are multilayer structures of reinforced plastics, metals and other materials honeycomb panels, antenna fairings, propellers, helicopter rotors and so on. In mentioned instruments amplitude-frequency analog signal processing is used. 

Instrument Designs for Infrared Absorption The simplest instrument for IR absorption spectroscopy is a filter photometer similar to that shown in Figure 10.24 for UV/Vis absorption. These instruments have the advantage of portability and typically are used as dedicated analyzers for gases such as ITCN and CO. 

Time, Cost, and Equipment In comparison with competing methods, potentiome-try provides a rapid, relatively low-cost means for analyzing samples. Commercial instruments for measuring pH or potential are available in a variety of price ranges and include portable models for use in the field. 

This on-going research aims at a) environmental monitoring and b) the development, after further research and collaboration with an instrument manufacturer, of a prototype portable flow toxicity meter as an early warning system for pollution. 

Leakage current monitor - this can be connected perma-nently for continuous reading or periodic monitoring. The normal practice is to measure only periodically for a short period to take average measurements on an hourly, daily, monthly or yearly basis. When not connected permanently, the instrument can also be used as a portable kit to monitor the condition of other arresters installed in the vicinity. Field probe - to compensate the third harmonic of the system voltage to make the IZnO free from the third harmonic of the system voltage. This method of /r measurement therefore provides more accurate and closer monitoring of the arrester. 

In electrochemical cells sample oxidation produces an electric current proportional to the concentration of test substance. Sometimes interferences by other contaminants can be problematic and in general the method is poorer than IR. Portable and static instruments based on this method are available for specific chemicals, e.g. carbon monoxide, chlorine, hydrogen sulphide. 

Analyses of gases and vapours tend to utilize the teehniques deseribed on page 308. Many of these methods were traditionally limited to laboratory analyses but some portable instruments are now available for, e.g., gas ehromatography (Table 10.16) and non-dispersive infra-red speetrometry (Table 10.17). 

Portable instrument should be of explosion-proof design fixed point systems may rely on remote sensing heads... 

HS(Gj49 The examination and testing of portable radiation instruments for external radiations... 

Monitor for airborne dust (surfaee or subsurfaee soil) with portable, aerosol dust direet reading instruments. 

Linear polarization instruments provide an instantaneous corrosion-rate data, by utilizing polarization phenomena. These instruments are commercially available as two-electrode Corrater and three electrode Pairmeter (Figure 4-472). The instruments are portable, with probes that can be utilized at several locations in the drilling fluid circulatory systems. In both Corrater and Pairmeter, the technique involves monitoring electrical potential of one of the electrodes with respect to one of the other electrodes as a small electrical current is applied. The amount of applied current necessary to change potential (no more than 10 to 20 mV) is proportional to corrosion intensity. The electronic meter converts the amount of current to read out a number that represents the corrosion rate in mpy. Before recording the data, sufficient time should be allowed for the electrodes to reach equilibrium with the environment. The corrosion-rate reading obtained by these instruments is due to corrosion of the probe element at that instant [184]. 

In its simplest form, the Wheatstone bridge is used on D.C. for the measurement of an unknown resistance in terms of three known resistors. Its accuracy depends on that of the known units and the sensitivity of the detector. It is also used for sensing the changes which occur in the output from resistance strain-gauge detectors. The latter instruments can be made portable and can detect variations of less than 0.05 per cent. 

A wide range of analysis instruments, either of the portable or permanently installed type, can be used. The latter will frequently be recording instruments and may have control capabilities. Various principles are employed in analysis equipment, including ... 

All bought-in items of plant, especially those supplied without adequate materials certification, should be subject to random inspection. Portable instruments are available for many types of non-destructive examination, chemical analysis and mechanical testing of fabricated items of plant. 

A variation of the Shepard Cane incorporates both electrodes on a single rod. A circuit diagram of this type of instrument is shown in Fig. 10.51. The single rod has a calibration constant, determined by the area of the positive electrode. At balance the resistivity is given by the resistance multiplied by the rod constant. This instrument is portable and simple to operate, but it cannot be recommended when accurate results are required. 

The advantages of this type of instrument are (a) that only one instrument is required for all necessary measurements, and (b) that it is portable and thus particularly suitable for held work. 

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