Handheld

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. 

In the original study (61), NTU /NTU was calculated for thousands of hypothetical design cases as a function of both Pe and Pep -pu- The results were correlated and empirical expressions were given that can be evaluated on a handheld calculator, just as equations 76 and 77, but which approximate the computer calculation much better, to within about 5%. 

Various types of detector tubes have been devised. The NIOSH standard number S-311 employs a tube filled with 420—840 p.m (20/40 mesh) activated charcoal. A known volume of air is passed through the tube by either a handheld or vacuum pump. Carbon disulfide is used as the desorbing solvent and the solution is then analyzed by gc using a flame-ionization detector (88). Other adsorbents such as siUca gel and desorbents such as acetone have been employed. Passive (diffuse samplers) have also been developed. Passive samplers are useful for determining the time-weighted average (TWA) concentration of benzene vapor (89). Passive dosimeters allow permeation or diffusion-controlled mass transport across a membrane or adsorbent bed, ie, activated charcoal. The activated charcoal is removed, extracted with solvent, and analyzed by gc. Passive dosimeters with instant readout capabiUty have also been devised (85). 

Handheld cameras using Polacolor 8.3 x 10.8 cm (3j x in.) pack films range from inexpensive amateur models to more expensive professional ones. The 10 x 13 cm (4x5 in.) pack films are also used in camera backs for professional and industrial appHcations. Polacolor 10 x 13 cm (4x5 in.) sheet films are used in holders that fit many specialized instmments, as well as view cameras the 20 x 25 cm (8 x 10 in.) film holder fits standard equipment. 

A separate unit is used for programming and editing (e.g. a handheld programmer or a computer). For on-line editing, keyboards are used. For on-line monitoring, a PLC is interfaced with a computer and special software. 

Detectable concentration ranges are mbe-dependent and can be anywhere from one-hundredth to several thousand ppm. The limits of detection depend on the particular detector mbe. Accuracy ranges vary with each detector mbe. The pump may be handheld during operation (weighing from 8 to 11 ounces), or it may be an automatic type (weighing about 4 pounds) which collects a sample using a preset number of pump strokes. 

Natural gas must always be contained in appropriate pipes or vessels and precautions taken to ensure that leakage cannot occur. If a gas leak does occur, the main gas supply should be shut off, the area ventilated and the gas supplier informed. Electrical switches should not be turned on or off, portable electrical appliances including handheld torches should not be operated and all other possible sources of ignition removed or rendered inoperable and the affected area ventilated. In circumstances of excessive leakage, the building should be evacuated. 

The data logger or microprocessor selected by your predictive maintenance program is critical to the success of the program. There is a wide variety of systems on the market that range from handheld overall value meters to advanced analyzers that can provide an almost unlimited amount of data. The key selection parameters for a data acquisition instrument should include the expertise required to operate, accuracy of data, type of data, and manpower required to meet the program demands. 

At the top end of the program monitoring scale is the use of online fluorescence tracing systems, whereby tracer dye polymers form part of the water treatment program and their concentration can be measured online at various locations throughout the boiler plant system. Much less expensive, handheld fluorometers are now available to conduct the same type of analysis at the laboratory bench or on the boiler house firing-floor. These tracer dye polymers can be used to determine ... 

Modem electronic replacements for the Orsat apparatus include equipment manufactured in the United States by Bacharach, Inc. (www.bacharach-inc.com). This company produces handheld and boxed instruments that can be employed as comprehensive combustion and environmental analyzers, gas burner combustion testers, single gas analyzers, draft gauges, smoke test sets, sling psychrometers, and the like. 

The use of wireless computer systems has gain popularity in data collection for clinical trials. They have been used as a substitute for normal paper-based patient diaries (Koop et al. [19]) to increase data quality and shorten the time needed to close the database. They have also been used for mobile interviewing [20] and for bedside data collection [21]. In patient-directed data entry, subjects are given handheld computers to answer the trial s questions (Clarke et al. [22]). 

Koop A, Mosges R. The use of handheld computers in clinical trials. Controlled Clin Trials 2002 23 469-80. 

The authors also demonstrated a low-technology method for recording the chemiluminescent signal of the bDNA assay. The light emission was recorded on black-and-white film Polaroid film using a handheld camera. The bDNA assay could be applicable to field situations because of the stability of the reagents and the ability to record the data without the use of sophisticated equipment. 

Standards Development Handheld Systems LIL, CSA Portable Systems CSA. UL. CGA Handheld Fuel Containers JJL, CSA, CGA Portable... 

The main advantages of the current YI sensor are that it is extremely sensitive, is a label-free technique, has multiplexing capabilities, and allows for a compact design. As such it is a good candidate for the development of a reliable handheld... 

Ymeti, A. Subramaniam, V. Beumer, T. A. M. Kanger, J. S., An ultrasensitive Young interferometer handheld sensor for rapid vims detection, Expert Rev. Med. Devices 2007, 4, 447 454... 

Figure 6.5 A fluorinated organically modified silicate doped with [Ru(dpp)3]2+ is a highly sensitive 02 sensor. Fluorine here ensures unprecedented sensitivity and a remarkable stability (2% drift over 6 months). The material has been implemented in sol-gel handheld oxygen sensors that are already commercialized. (Reproduced from ref. 6, with permission.)...

---