SINGLE FIBRE

Filament This is a single fibre which is continuous or at least very long compared with its diameter. 

Fig. 16.19. Hollow-fibre module and, inset, a single fibre.

The construction of the optoelectronic interface can be based on a silicon photodiode since analytical and reference wavelengths are from the visible and the IR regions, respectively. The signals can be filtered out by optical filters (then two photodiodes are required) or one photodiode can be synchronised with modulation waves of the LEDs used. Finally, silica optical fibres can be used as light waveguides. The choice between single fibre or bundle is determined by the application of the sensor. 

Figure 5. Single-point IR sensor head layouts a transmission probe with fibre coupling b transflectance probe with variable pathlength and single fibre coupling c (diffuse) reflection probe with single illumination fibre and collection fibre bundle d two-reflection ATR probe with fibre-optic coupling e multi-reflection ATR probe (DiComp -type) f ATR fibre...

Bram, A., Branden, C. I., Craig, C., Snigireva, I., and Riekel, C. (1997). X-ray diffraction from single fibres of spider silk. /. Appl. Crystallogr. 30, 390-392. 

Ruigrok, R. W., Barge, A., Albiges-Rizo, C., and Dayan, S. (1990). Structure of adenovirus fibre. II. Morphology of single fibres./. Mol. Biol. 215, 589-596. 

Goda, K., Park, J. M. and Netravali, A. N., A new theory to obtain weibull fibre strength parameters from a single-fibre composite test, J. Mater. Sci., 30, 2722 (1995). 

For the present purpose anionic dyes are classified as those containing sulfonic acid groups or those capable of solubilization in alkali, such as vat dyes. Such dyes are usually applied to fibres with hydrophilic character such as cotton, which is still the most important single fibre from a point of view of world usage, nylon and wool. Azoic dyes and direct dyes, although economically important, will not be discussed. Pigments, which are sometimes used in cotton printing, are treated separately. 

A particularly interesting property of Durham polyacetylene is that it can be stretched to draw ratios of up to 20 during the transformation, to yield a polyacetylene sample with high levels of orientation. This effect was reported by Bott et al. 378) for thin films in the electron microscope and then by Leising et al. 379), who drew single fibres of polyacetylene to a highly oriented /rani-state with a density of 1.06 g cm-3. 

The test should always be carried out on the single fibres and without previously subjecting them to any preliminary treatment with water or other chemical reagents. 

We were unable to explain the large difference in the tensile strengths of a single fibre and a wrapped fibre, nor the high tensile strength of the fibres treated with water glass. The latter was contrary to our expectations that the concentrated alkali in the water glass would affect the fibre structure. 

UMEs used in our laboratory were constructed by sealing of carbon fibre into low viscosity epoxy resin (see Fig. 32.4) [118]. This method is simple, rapid and no specialised instrumentation is required. Firstly, the fibres are cleaned with this aim. They are immersed in dilute nitric acid (10%), rinsed with distilled water, soaked in acetone, rinsed again with distilled water and dried in an oven at 70°C. A single fibre is then inserted into a 100- iL standard micropipette tip to a distance of 2 cm. A small drop of low-viscosity epoxy resin (A. R. Spurr, California) is carefully applied to the tip of the micropipette. Capillary action pulls the epoxy resin, producing an adequate sealing. The assembly is placed horizontally in a rack and cured at 70°C for 8h to ensure complete polymerization of the resin. After that, the electric contact between the carbon fibre and a metallic wire or rod is made by back-filling the pipette with mercury or conductive epoxy resin. Finally, the micropipette tip is totally filled with epoxy resin to avoid the mobility of the external connection. Then, the carbon fibre UME is ready. An optional protective sheath can be incorporated to prevent electrode damage. 

Part of the neuron consisting of a single fibre down which the action potential is transmitted to the nerve terminal. 

Shao, Z.Z., Young, R.J., and Vollrath, F. "The effect of solvents on spider silk studied by mechanical testing and single-fibre Raman spectroscopy". Int. J. Biol. Macromol. 24(2-3), 295-300 (1999). 

Single fibre pull-out test 179 Site energy distribution 47 Skin 124... 

Figure 37 Electron micrographs of self-assembled fibres, (c) Electron micrograph showing the dense network of long helical fibres in a steroid/cyclohexane organogel, (d) Preparation of single fibres, demonstrating their helical superstructure [425]. (e) Cyclic oligopeptides, selfassembling into nanofibres [435,436], Reproduced with permission of The Royal Society of Chemistry and The American Chemical Society. Parts (c) and (d) 1986 American Chemical Society...

The most common microtraces examined in criminalistic laboratories are so-called contact traces (i.e. small fragments of paint coating, glass, single fibres, soil, writing materials). Moreover, traces of flammable liquids originating from fire debris or traces pointing to the use of firearms are revealed and identified. 

Baker, D.J., Sedgwick, E.M. (1996). Single fibre electromyographic changes in man after organophosphate exposure. Hum. Exp. Toxicol. 15 369-75. 

Viets C, Hill W (2000) Single-fibre surface-enhanced Raman sensors with angled tips. J Raman Spectrosc 31(7) 625-631... 

Experimentally, the single fibre is attached to the arm of an electro-balance and immersed first in the hydrocarbon alone, and then in both hydrocarbon and polar liquid phases. Weight increases at each stage are measured. Static and dynamic experiments, in immersion and emersion, have been conducted. 

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