Core sheath type

Core sheath type (C/S) In this type of fibre one of the components is completely surrounded by another component. Core sheath type fibres can be self-bonding (e.g. two components with varying melting points with the lower melting point polymer on the sheath), surface tailored fibres (e.g. sheath containing expensive additives) or filled fibres (e.g. a core of recycled material covered by a sheath with the desired properties). 

Horn fi om the rhino is different firom other types of hom, as it is composed entirely of compacted strands of keratin, so that it is solid with no bony core. Other types of hom are thin sheaths of homy material covering a bony core. Rhinos horns grow throughout the animals lives, and can regrow if broken or damaged. They grow om the skin on the animals noses (Fig. 6.1). 

Kurzbock (1987) patented a kern-mantel (core-sheath) rope, of the type shown in Fig. 15.3. He claimed the relatively hard sheath resisted wear from contact with rock, carabiners, etc. The braided sheath also holds the components of the core together, especially when the rope is bent around a small radius. It prevents the core strands contacting the rock. The sheath is flexible because of the helical path of the strands. The rope is a composite the braided sheath resists abrasion and acts as a barrier to moisture, dirt and UV light, while the twisted core takes the main tensile loads. 

We have for a number of years developed polymer-based piezoelectric textile filaments and yarns [44]. Filaments are melt spun and bicomponents core-and-sheath type based on a blend of a normal bulk polymer like high-density polyethylene and the piezoelectric material (PVDF), surrounding a core of a conductive polyethylene-carbon black mixture (see Fig. 28.25). The core is electrically conductive and will act like an electrode. 

A bi-component electro-spirming technique can produce core sheath stmctures, in which one type of material forms the core, and the other forms an outer shell. Several variations are possible, including having materials side by side, or one material in a different shape such as a star, pie wedge, sea island or even a custom design across the cross section embedded in an outer sheath. 

Every type of fibre has spedaUst end uses. Side-by-side fibres and eccentric core/sheath fibres possess the often desired property of self-crimping. Drawing or heating the sides of such fibres causes the fibre to wrap itself into a helical configuration, the intensity of which wUl be a function of the thermal behaviour of the materials used and their arrangement. The... 

Although the existing fibre-making technique is able to produce a bicomponent fibre of many cross-sectional structures, the production of bicomponent nanofibres has been limited to two basic types of cross-sectional structures, the core-sheath and the side-by-side . These bicomponent nanofibres are eiectrospun via special spinnerets. Two polymer solutions flow within the spinneret as the sheath and core, or side-by-side, to the tip of the nozzle and then are subjected to a co-electrospinning process. The formation of bicomponent nanofibres is determined by the laminar bicomponent jet. 

Screened SL construction (HSL type) which, in addition to possessing its own insulation and screen also has a separate lead sheath for each core as against a common lead sheath in the other two types... 

The header cable between anode bed and rectifier must be particularly well insulated. For this reason cables with double plastic sheathing of type NYY-O are used. The cable sheath must not be damaged during installation because the copper core at the defects will be anodically attacked in a very short time and the connection to the rectifier broken. Damage to the cable sheath is not so serious if a multicored cable is used. Usually not all the core insulation is damaged so that the operation of the anode bed is not interrupted. In addition, measurement of resistance and detection of defects is easier. 

There are four types of SCS fibers depending on the thickness of the final SiC coating designed for different metal matrices. They are the standard SCS, SCS-2, SCS-6 and SCS-8. Fig. 5.30 illustrates schematically the cross sections of two commercially produced SiC fibers, the standard SCS and SCS-6 fibers, according to DiCarlo (1988). Both types of fibers consist of a carbon core of 37 pm in diameter, a SiC sheath of varying thickness and a carbon-rich surface coating of 0-4 pm in... 

A better alternative would be to have fibres that in their own right could show multiple colours based on the direction of view. One model for this is a fibre that consists of a concentric core and a sheath, each made from different types of polymers. For instance, constructing a fibre where one fibre is acid dyeable nylon and the other basic dyeable nylon make it possible to dye the sheath and the core in different colours. The colour change i.e. hue shift) then varies with the angle of incidence of light on the fibre. 

Armor-Piercing Discarding Sabot (APDS).. In this type of projectile, a carbide core, either capped or uncapped, is placed inside a steel or light-alloy sheath (fitted with a tracer) to give good exterior ballistic characteristics, and this subcaliber assembly is placed inside a full-caliber carrier. This carrier (sabot) is so designed that it will impart velocity and spin to the subcaliber projectile. 

The variability can be accounted for largely by the diffusion barriers of the different fibre types and by Na+ channel density. For example, the presence of a Schwann cell and myelin sheath poses a considerable barrier to the diffusion of local anaesthetic to the interior of the cell. There is in vitro evidence to indicate that all desheathed nerves require a similar minimum concentration of local anaesthetic to induce block irrespective of fibre type. A consequence of the physical architecture of a mixed nerve is that access of the drug to the outer fibres is easier than access to fibres at the core. It is for this reason that the onset of proximal analgesia of the limb precedes distal analgesia with a brachial plexus block. 

The technical term for this is hydrodynamic focusing, flow of a sample stream within the center core of a sheath stream is called coaxial flow. The exact diameter of that central sample core within the sheath stream is related to, among other things, the rate at which the sample is injected into the sheath stream a 100 pm sheath stream may, depending on sample injection velocity, have a core width of perhaps 5-20 pm (Fig. 3.4). Because hydrodynamic focusing tends to confine the cell sample to this central core, there is little mixing of sample with sheath fluid (but diffusion of small molecules will occur). The reason that this type of coaxial sample flow suits flow cytometry... 

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