Specialized Applications

In many applications, modification of PET fiber properties is desirable in order to enhance certain features of the product or to enhance the process of converting fibers into finished goods. In these cases, most of the basic PET fiber properties are acceptable but certain enhancements are desired, even at the expense of other properties or costs that will be affected by the modification. These side effects are always present it is the goal of fiber development personnel to engineer the best compromise. 

What follows are some of the most common variations that have been applied to PET fibers more complete information is available in the literature [11], 

The light reflectance of yarns and fabrics can be quite sensitive to tire size and shape of tire fibers. Two types of light interactions occur, as follows  

The mixture of tliese two types of light is what meets the eye, and the ratio of tliese two components affects tlie perceived deptli of color. The higher the ratio of specular reflection, tlien tlie less tlie apparent color depth. Additionally, any relatively large areas of specular reflection can generate visible points of light when oriented to reflect from point sources tliese cause the fibers or fabrics to glitter. 

Polymer transparency also requires that the crystalline regions be smaller than the wavelength of light, since these regions also represent changes in refractive index. Larger crystallites will scatter light at their interfaces and make the PET opaque. 

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The subroutine is well suited to the typical problems of liquid-liquid separation calculations wehre good estimates of equilibrium phase compositions are not available. However, if very good initial estimates of conjugate-phase compositions are available h. priori, more effective procedures, with second-order convergence, can probably be developed for special applications such as tracing the entire boundary of a two-phase region. 

Special products silicones, silicates, polyphenylethers, used rarely and for very specialized applications because they are expensive materials. 

Road paving. This includes bitumen, cutbacks and fluxed bitumen as well as emulsions. Each of these products is subject to very special application techniques. This list is completed by the use of poured asphalt, even though this product is better suited to smaller surfaces sidewalks, courts, etc., than to pavements. Since the middle of the 1980 s, air-blown bitumen is no longer used for road construction. 

Since metal-ceramic technology due to some reasons is the more expensive technology, its use presently is restricted to high-power or special applications. 

Due to the pulsed radiation output of the LINAC the detectors and the detector electronics have to handle very high counting rates in very short periods. Therefore the detectors have to work in a mode, where the detector output is integrated for one or several beam pulses. For that purpose the crystals are coupled to photo- diodes. Their currents are read out and analysed by the electronic board, which has been developed for this special application. 

In order to obtain a high signal-to-noise ratio sufficient acoustical power is necessary. For special applications a programmable pulser (transmitter) is required in order to optimize the frequency spectrum. 

For special applications such as air coupled testing a special programmable transmitter board was developed. This transmitter generates rectangular and burst signals, which increase the acoustical power in an optimized frequency range, and provides a superior signal-to-noise ratio. 

The Evaluation system is a Windows based open system through DLL, Dynamic Link Library, which provides great flexibility in evaluation and presentation of data. It also makes it possible to customise evaluation and images for special applications The time gates can be set after testing and there is a 256 colour range for amplitude. The software include FFT -facilities which enables measurements on used probes for parameters such as center frequenzy and bandwidth. 

Another specialized application of EM image contrast is mass measurement. Using the elastic dark-field image in the STEM or the inelastic image in the EETEM, a direct measurement of the scattering mass can be performed. Eor reviews on this teclmique see [60.61]. 

For bulk structural detemiination (see chapter B 1.9). the main teclmique used has been x-ray diffraction (XRD). Several other teclmiques are also available for more specialized applications, including electron diffraction (ED) for thin film structures and gas-phase molecules neutron diffraction (ND) and nuclear magnetic resonance (NMR) for magnetic studies (see chapter B1.12 and chapter B1.13) x-ray absorption fine structure (XAFS) for local structures in small or unstable samples and other spectroscopies to examine local structures in molecules. Electron microscopy also plays an important role, primarily tlirough unaging (see chapter B1.17). 

Kirkwood J G 1934. Theory of Solutions of Molecules Containing Widely Separated Charges witl Special Application to Zwitterions. Journal of Chemical Physics 2 351-361. 

A special application of the Japp-Klingemann/Eischer sequence is in the preparation of tryptamines from piperidone-3-carboxylate salts, a method which was originally developed by Abramovitch and Shapiro[2]. When the piperidone is subjected to Japp-Klingemann coupling under mildly alkaline conditions decarboxylation occurs and a 3-hydrazonopiperidin-2-one is isolated. Fischer cyclization then gives 1-oxotetrahydro-p-carbolines which can be hydrolysed and decarboxylated to afford the desired tryptamine. 

With the exception of pneumatic controllers for special applications, commercial single-loop controllers are almost entirely microprocessor-based. The most basic products provide only the PID control algo-... 

Special applications, such as in high-magnetic fields, require special thermometers. The carbon-glass and strontium-titinate resistance thermometers have the least magnetoresistance effects. 

Mixed-feed operation is used only for special applications, as when liquor at an intermediate concentration and a certain temperature is desired for additional processing. 

Breakup of a low-velocity liquidjet (Ih/elocity) . This governs in special applications like prilling towers and is often an intermediate step in liquid breakup processes. 

There are, however, certain special applications where the filter medium around the edge of the section may be dehberately blinded by painting in order to improve cake discharge. This technique is most frequently used on disk filters, with the result that the actual area may be only 75 to 85 percent of the nominal area. This is a significant deviation from the nominal area and must be considered separately. 

Alternatively, A- ylium names may be formed by a special application of the A convention, according to which the affected atom is considered to be formally derived from a hypothetical parent that has a hydridic hydrogen attached in lieu of the positive charge. Such an operation... 

Manufacturers, depending upon market needs, may adopt all or a few such designs or even have their own designs, still conforming to such stipulations. Special applications may, however, call for a custom-built motor as noted later. As a standard practice all HT motors are custom-built for each application and no rotor designs are prescribed for these. 

Ghosh, S.N., Electric motors lor special applications . Siemens Circuit, V , No. 4, July (1972). 

For special applications, however, such as for normally humid areas, and contaminated or chemically aggressive locutions, epoxy paints tne con.sidered to be more appropriate. They provide a protective coating which is resistant to chemical fumes, corrosion and temperature. Chlorinated rubber paints, which also fall into the same category of protective paints, may also be used for these areas but, not being temperature resistant, are not preferred to epoxy paints. 

These are protection CTs lor special applications such as biased differential protection, restricted ground fault protection and distance protection schemes, where it is not possible to easily identify the elass of accuracy, the accuracy limit factor and the rated burden of the CTs and where a full primary fault current is required to be transformed to the secondary without saturation, to accurately monitor the level of fault and/or unbalance. The type of application tind the relay being used determine the knee point voltage. The knee point voltage and the excitation current of the CTs now form the basic design parameters for such CTs. They are classified as class PS CTs and can be identified by the following characteristics ... 

With application of solid-state technology, this shortcoming of an electromagnetic relay is automatically overcome. The solid-state relays are available with switching stages as many as from 2 to 16. For special applications, they can be designed for even higher numbers of steps. 

There are less exotic ways of increasing the strength of cement and concrete. One is to impregnate it with a polymer, which fills the pores and increases the fracture toughness a little. Another is by fibre reinforcement (Chapter 25). Steel-reinforced concrete is a sort of fibre-reinforced composite the reinforcement carries tensile loads and, if prestressed, keeps the concrete in compression. Cement can be reinforced with fine steel wire, or with glass fibres. But these refinements, though simple, greatly increase the cost and mean that they are only viable in special applications. Plain Portland cement is probably the world s cheapest and most successful material. 

Straight-lobe compressor casings, also called housings or cylinders by different manufacturers, are furnished in cast iron by all vendors. There is an optional aluminum construction available for special applications. Inlet and outlet are suitable for a 125 pound standard ANSI flanged connection. 

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