Fiber tracer

Fiber tracer A fiber or yarn added to a prepreg for verifying fiber alignment, in the case of woven materials for distinguishing warp fibers from fill fibers, etc. 

Figure 2 Photograph of X-ray observation of brass fiber tracers in injection...

Polyester composition can be determined by hydrolytic depolymerization followed by gas chromatography (28) to analyze for monomers, comonomers, oligomers, and other components including side-reaction products (ie, DEG, vinyl groups, aldehydes), plasticizers, and finishes. Mass spectroscopy and infrared spectroscopy can provide valuable composition information, including end group analysis (47,101,102). X-ray fluorescence is commonly used to determine metals content of polymers, from sources including catalysts, delusterants, or tracer materials added for fiber identification purposes (28,102,103). 

Tracer yam Strand of glass fiber colored differently from the remainder of the roving package. It allows a means of determining whether equipment used to chop and spray glass fibers are functioning properly and provides a check on quality and thickness control. 

Neuroanatomists have taken advantage of the phenomenon of fast retrograde transport to locate remote nerve cell bodies in the CNS of an experimental animal that are connected to an identified axonal fiber tract whose origin is uncertain. The tracer material [purified horseradish peroxidase (HRP) enzyme] is injected in the region of the axon terminals, where it is taken up by endocytosis and then is carried by retrograde axonal transport over a period of several hours to days back to the nerve cell body. The animal is sacrificed, and the enzyme tracer is localized by staining thin sections of the brain for peroxidase activity. 

A fiber optic immunosensor (FOI) has also been reported for detection of PCBs in Aroclors [204]. The quartz fiber surface is coated with PAbs against PCBs and the competitive assay takes place using as fluorescent tracer, an analog of the analyte coupled to 2,4,5-trichlorophenoxybutyrate (TCPB) on the Ab-coated fiber. The LOD achieved is around 10 pg L L... 

An evanescent wave fiber optic immunosensor has been used for the detection of ricin in river water.(131) A tapered fiber optic waveguide with covalently bound anti-ricin IgG is used in a sandwich format, with tetramethylrhodamine-labeled antibody as tracer. In a two-step format, ricin in the sample is bound to the fiber first, and then the fiber is exposed to the tracer antibody. Sensitivity is 1 ng/ml for the two-step assay. The one-step assay, in which the fiber optic probe contacts the sample and labeled antibody simultaneously is less sensitive, but more convenient. 

Ng and Assirelli have carried out a mixing study in batch stirred vessels with working volumes of 3 L to 20L using a fiber-optic UV-vis monitoring technique. Bromophenol blue sodium salt was used as a non-reactive tracer. The results on traditional Rushton turbines and 45° angled pitched blade turbines showed good agreement with a typical conductivity technique and a correlation proposed in literature. 

A fiber rotating band and a plastic obturator are assembled on the outside of the proj near the base of the sabot. During proj flight, the tracer burns for a minimum of 2.5 seconds. The sabot discards upon leaving the gun muzzle (with velocity of 4850fps) by setback, centrifugal and air-pressure forces. The sheathed core penetrates the target by kine-... 

P.-F. Cevey and U. von Stockar, A tracer system based on a photochromic dye and on fiber optics for measuring axial dispersion of organic liquids in pilot-scale packed columns, Chem. Eng. J., 31, 7-13 (1985). 

Morgan A, Collier CG, Morris KJ, et al. 1993. A radioactive tracer technique to determine in vivo the number of fibers in the lungs of rats following their administration by intratracheal instillation. Environ Res 63(2) 182-190. 

For example, several strategies have been used for immunoassay techniques with fiber-optic biosensors. In the sandwich format, the receptor is immobilized on the stu"face of the fiber waveguide and a secondary or tracer antibody (which is labelled with a fluorescent dye) is added to the solution. In the absence of the analyte, the tracer remains in solution and little fluorescence is observed. However, after addition of the analyte, a molecular sandwich is formed on the sensor smface within the evanescent excitation volume. The sandwich assay is usually more sensitive than a competitive-binding assay because the fluorescence intensity increases with analyte concentration. 

Vitamin Bi, vitamin B2, and nicotinic acid, all of which frequently occur together in foods, were separated by TLC and fluorimetrically determined by using a commercially available fiber optic-based instrument. A fluorescent tracer (fluoresceinamine, isomer II) was used to label the nicotinic acid. Vitamin B1 was converted to fluorescent thiochrome by oxidizing with potassium ferricyanide solution in aqueous sodium hydroxide. These vitamins were separated by HPTLC on silica gel using methanol-water (70 30 vol/vol) as mobile phase. Under these conditions, the Rf values of the vitamin Bi, vitamin B2, and nicotinic acid derivatives were 0.73, 0.86, and 0.91, respectively. 

A sequential two-step immunoassay for FT4 was first introduced commercially in 1979. Subsequently, a number of manual and automated procedures have become available for FT4 and FT3. The earliest kit methods used radioactive labels and antibody-coated tubes or microbeads, but automated systems are now available that use nonisotopic tracers and a variety of sofid-phase formats. One two-step FT4 method involves the application of serum to glass-fiber... 

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