Accessory

To obtain the desired spectra of samples, the spectroscopist will require a variety of accessories in addition to the instrument. The purpose of a number of these accessories is to hold the sample that of others is to permit the use of additional techniques and that of the remainder is to extend the usefulness of the instrument. This chapter will very briefly discuss the construction and use of the most common types of commercially available accessories. For a more detailed description, the spectroscopist should refer to the literature of the various instrument and accessory manufacturers. 

Many accessories require windows or lenses of an infrared trans- mitting material. These materials are listed in Table 2-1 of Chapter 2. The most commonly used crystals are sodium chloride (NaCl), potassium bromide (KBr), cesium bromide (CsBr), and cesium iodide (Csl). As these crystals are all water soluble, hygroscopic, and easily damaged, they require special care and handling. The wider the infrared transmission range, the more hygroscopic and easily damaged they are. 

Directions for construction of a pitch lap can be found in a good book on optical polishing. 

A hairline eyepiece, an ocular micrometer or standard graticule, and a stage micrometer, provided for microscopy. Routine laboratory material and ancillary instruments to carry out gravimetric testing, that is, balance, oven, desiccator, measuring cylinders, stop watch, watch glasses, and so on. 

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As described above 2314 ROIs were cut out of several radiographs of austenitic welds and the accessory feamres were calculated. The true data for each radiograph is known by destructive testing and evaluation. The ROIs represent the following dataset ... 

The scope of the directive covers the design, manufacture and conformity assessment of pressure equipment and assemblies with a maximum allowable pressure greater than 0,5 bar. A pressure equipment in the sense of the directive is any vessel, piping, safety accessory or pressure accessory. An assembly means several pieces of pressure equipment assembled by a manufacturer to constitute an integrated and functional whole. It is important to be aware that the directive relates exclusively to the pressure risk and that therefore other directives, such as for machinery, low voltage may be applicable to the equipment concerned. 

Based on these considerations, the conformity assessment tables comprise 4 tables for vessels and 4 tables for piping. A further table relates to fired or otherwise heated equipment. Specific procedures are set out for the assessment of assemblies and of safety accessories. 

A variety of commercial instruments are available for the determination of the viscoelastic behavior of samples. Figure 3.15 shows one such apparatus, the Rheovibron Viscoelastometer. This instrument also takes advantage of the complementarity that exists between time and temperature It operates at four frequencies over a 175°C temperature range. With accessories, both the frequency range and the temperature range can be broadened still further. 

Versatility the scale components can be purchased individually and used to create custom configurations AvadabiHty of a wide range of accessories for data acquisition or process control... 

Before the fibers can be spun into yams, a certain amount of preparation is necessary for cleaning and removal of undesirable accessory materials such as fat, wax, gum, or pulp. The weighting of sUk is a process to counter the weight loss resulting from degumming the fibers using heavy metal salts of tin or bismuth. This process affects the durabUity and long term preservation. 

Operator skih and experience are necessary to obtain consistent results usiag a Durometer. Speed of load appHcation, dweh time, and sample thickness can affect reproducibhity of results. Durometer cahbration prior to each test series is done usiag a test block provided with the iastmment. When large numbers of tests are required, improved consistency of results are obtained if the Durometer is used with the accessory vertical stand rather than hand held. 

The successful employment of any insecticide depends on its proper formulation into a preparation that can be appHed for insect control with safety to the apphcator, animals, and plants. Insecticides are commonly formulated as dusts, water dispersions, emulsions, and solutions. The preparation and use of such formulations involves accessory agents such as dust carriers, solvents, emulsifiers, wetting and dispersing agents, stickers, and deodorants or masking agents (1). 

Helping to propel capacities upward has been the advent of greatly improved preheaters, which partially calcine the stone and significantly improve thermal efficiency. Modem preheaters improve capacity by 15—20% and decrease fuel consumption a similar percentage. Other kiln appurtenances and accessories that enhance efficiency and lime quahty are the contact coolers, and such kiln internals as metal refractory trefoil systems that act as heat exchangers, dams, and lifters. 

The hard rock deposits are mined mainly for feldspar with mica and quartz being accessory minerals. These deposits are extensive, often covering hundreds of square meters and are recognized by the light-colored, granite-like appearance with shiny mica flakes being a prominent feature. The mica content of these deposits ranges from approximately 6—10 wt %. 

Because of its high modulus of elasticity, molybdenum is used in machine-tool accessories such as boring bars and grinding quills. Molybdenum metal also has good thermal-shock resistance because of its low coefficient of thermal expansion combined with high thermal conductivity. This combination accounts for its use in casting dies and in some electrical and electronic appHcations. 

The hand lay-up or spray-up process, used universally for the production of laminar composites incorporating glass fiber reinforcement, is most efficient for the manufacture of large parts, such as boats, bathtubs, tanks, architectural shapes, and recreational accessories. Resins intended for spray-up processes are usually modified with thixotropic additives, such as fumed siHca (1%), to reduce the risk of drainage when appHed over large vertical mold surfaces. Molds are also made from ERP for short-mn products usually surfaced with a tooling gel coat to provide consistent surface quaHty and appearance. 

Various accessories can be suppHed along with the control valves for special situations. Positioners ensure that the valve stem is accurately positioned following small or slowly changing control signals or where unbalanced valve forces exist. Boosters, which are actually pneumatic amplifiers, can increase the speed of response or provide adequate force in high pressure appHcations. Limit switches are sometimes included to provide remote verification that the valve stem has actually moved to a particular position. 

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