Detection devices

Such requirements are meant to change the usual configurations and technologies usually associated with photothermal set-up. These changes mainly affect the IR detection devices, the optical components associated with the excitation and detection flux and the signal acquisition hardware and software. Figure 9 presents a sketch of the so-called pre-industrial demonstrator built from those different improvements. 

Optional additional detection device before entry to mass Spectrometer proper... 

The KDF filter was first tested in prototype on a coal mine in northern Germany. It was installed in parallel with existing vacuum filters and it produced filter cakes consistendy lower in moisture content by 5 to 7% than the vacuum filters. Two production models have been installed and operated on a coal mine in Belgium. The filter is controlled by a specially developed computer system this consists of two computers, one monitoring the function of the filter and all of the detection devices installed, and the other controlling the filtration process. The system allows optimization of the performance, automatic start-up or shut-down, and can be integrated into the control system of the whole coal washing plant. 

Fire-detection devices such as flame-sensing or ioni2ation-interference types operate much more rapidly than sprinkler heads and are used extensively both as alarms and to activate fixed fire-extinguishing systems. 

Continued advances in analytical instmmentation have resulted in improvements in characterization and quantification of chemical species. Many of these advances have resulted from the incorporation of computet technology to provide increased capabiUties in data manipulation and allow for more sophisticated control of instmmental components and experimentation. The development of rniniaturized electronic components built from nondestmctible materials has also played a role as has the advent of new detection devices such as sensors (qv). Analytical instmmentation capabiUties, especially within complex mixtures, are expected to continue to grow into the twenty-first century. 

The use of separation techniques, such as gel permeation and high pressure Hquid chromatography interfaced with sensitive, silicon-specific aas or ICP detectors, has been particularly advantageous for the analysis of siUcones in environmental extracts (469,483—486). Supercritical fluid chromatography coupled with various detection devices is effective for the separation of siUcone oligomers that have molecular weights less than 3000 Da. Time-of-flight secondary ion mass spectrometry (TOF-sims) is appHcable up to 10,000 Da (487). 

The U.S. Mine Health and Safety Act of 1969 requires that a mine be closed if there is 1.5% or more methane in the air. The use of an electrical methane detection device is required. High capacity ventilation systems are designed to sweep gases from the cutting face and out of the mine. These systems remove all gases before they become harm fill. 

Tritium is readily detectable because of its radioactivity. Under certain conditions concentrations as low as 370 )-lBq/mL (10 //Ci/mL) can be detected. Most detection devices and many analytical techniques exploit the ioni2ing effect of the tritium P-decay as a principle of operation (62,63). 

There are usually several reactors hnked to a single catch tank. To ensure that rupture of a disk on one reac tor does not affect the others, each reactor is fitted with a double-rupture-disk assembly. The use of double rupture disks in this apphcation requires installation of a leak detection device in the space between the two disks, which... 

Provide safe separation distances Install fixed fire protection and alarms, water sprays (deluge), and/or foam systems activated by flammable gas, flame, and/or smoke detection devices... 

For filter boxes, provide remote and automatic filter box lid closing on trip of appropriate fire detection device. Fire detection device may also be interlocked to stop solvent feed, trip deluge internal to filter box and/or trip inert gas blanket for filter box (caution, be aware inert gas is a potential asphyxiation hazard)... 

In all static surge-detection devices, the actual plienonemon of flow reversal (surge) is not directly monitored. What is monitored are other conditions related to surge. Control limits are set from past experience and a study of compressor characteristics. 

A Btu meter may be used in the fuel-quality system as an aid in determining turbine system efficiency. A water capacitance probe is used for detection of water in the fuel line. A water-detecting device can be incorporated into the corrosion monitoring system. This monitoring device is based on detection of changes in the dielectric constant of unknown fluid components... 

The primary protection for high temperature, which could lower the maximum allowable working pressure below the PSV setting, is a high-temperature sensor (TSH), which shuts in the inlet or the source of heat. Back-up protection is provided by leak detection devices. 

Develop monitoring/detection devices that are more durable, cost effective, reliable, and accurate... 

The recent rise in the use of expolosives in terrorist activity poses new challenges to industry and law enforcement. This challenge is being met by the use of sophisticated chemical detection devices to screen for bombs and more rigorous explosive inventory safeguards and controls. Plans have also been proposed to tag explosives with isotopes to make them easier to trace if misused. 

Electronic detection systems may range from simple intmder-detection devices monitored by basic control units to a variety of complex systems monitored by sophisticated computer-operated controls linked to 24-hour manned stations. Intruder-detection devices can be arranged into the following groups ... 

Static detection devices would include the following ... 

Movement-detection devices are designed to detect the movement of an intmder in the interior of the building ... 

In many cases, it is necessary to complement physical security by the installation of an intruder alarm system in order to achieve the standard of security commensurate to the risk exposure. The scope of protection to be afforded by the alarm system depends on the security risk, but it may embrace fences, windows, doors, roofs, walls, internal areas, yards and external open areas, and vehicles inside and outside buildings. There is a comprehensive range of detection devices, but the choice of detector is critical to ensure that it provides the desired level of protection and is stable in the particular environment. 

Electronic developments have revolutionized many types of laboratory equipment. Few instruments with dials are seen today, for instance. Digital readouts have taken over. While easier to use, estimating the amount of fluctuation of unstable signals is more difficult on a digital readout. There are also cases where an instrument s readout is more sensitive than its detection device, thereby causing unstable readings. For certain applications, a dial instrument may still be preferable. Electronic balances are now the rule rather than the exception. They are not only easy to use, but they generally require less service than mechanical ones. Prices have been considerably reduced in recent years. 

The final component to be discussed is the detection device of which much has already been written (2,21,22). Table 3 lists the most popular detectors at the present time with an indication of the detection limits obtainable for favorable substances. 

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