Cold Rolled Grain Oriented (CRGO) silicon steel is used extensively in transformers as core material. This material help to save energy and protects environment. This material is a less expensive one and also helps to reduce core frame size. Cost of windings and cost of oil also can be minimized by the usage of this material. CRGO slitting is a process where the initial coil slits into narrow hoops. But chances of deterioration of magnetic properties emerges as a result of this fine slitting. To minimize this, the head portion of the slitter line is properly designed. Eight different stages of slitting operation are pay-off reel, pinch roll, loop, rotary shear, deburring roll, loop, tension device and tension reel. During slitting, cutting blade sharpness has to be set to yield minimum burr at the slit edge.
Thursday, 21 June 2012
Furnace is an essential equipment in the production of quality nanosized materials. In the conventional method of production of microsized particles, starting precursors are properly treated and put in a furnace. On fine milling of these materials, nanomaterials are produced. But for good homogeneity, mixing and heating is required after fine milling. For heating, furnaces are used. If you are starting from chemical methods, for example, chemical co precipitation, self assembly, sol gel etc, again furnace has to be used for moderate sintering.
Wednesday, 13 June 2012
Foamed plastics are plastics whose apparent density is decreased substantially by the presence of numerous cells disposed throughout its mass. Foamed plastics are also known as cellular plastics or expanded plastics. Foamed plastics are two phase systems where dispersion medium is synthetic rubber or plastic and dispersed medium is a gas. During manufacturing, a fluid polymer is expanded into a cellular state followed by proper stabilization. During heat treatment of polymer, a blowing agent is used. This blowing agent gets entrapped into the polymer structure. Some examples of polymers used here are polystyrene, PVC, polyethylene, styrene-acrylonitrile copolymers etc. Blowing agents used here are pentanes, hexanes, halocarbons etc. Frothing process can also be utilized for the production of cellular polymers. Here a gas is dispersed in a fluid to produce a foam, which is then stabilized. Foamed plastics are widely used nowadays for thermal and electrical insulation, for the packaging of delicate instruments, for making pillows and mattresses and for providing buoyancy in boats and sea-borne cables.
Monday, 11 June 2012
Optical fibers as waveguides are widely used in communication and medicine. Optical fibers are used in different types of sensors. An optical fiber is consists of a cylindrical core made of a material of refractive index n. This cylindrical core is surrounded by a cladding made of a material of refractive index n’. This core-cladding system is surrounded by a plastic jacket. Based on the material used foir the construction, there are three types of fibers. They are glass fiber, plastic fiber and PCS fiber. Glass fibers use glass material for the construction of both core and cladding. Plastic fiber use plastic material for the construction of both core and cladding. PCS fiber use plastic material for the construction of cladding and glass material for the construction of core. Some of the methods used for the construction of optical fiber are double-crucible method, inside vapour deposition method, outside vapour deposition method, chemical vapour deposition method, modified chemical vapour deposition method, plasma enhanced modified chemical vapour deposition method, plasma activated chemical vapour deposition method, plasma outside deposition method and vapour phase axial deposition method.
Scanning electron microscopy and EDX studies on magnetic nanoparticles is a good characterization tool before proceeding to magnetic fluid preparation. Scanning electron microscopy gives idea about the grain size. X-ray diffraction data and scanning electron microscopy data, if combined together, gives exact nature of grain structure and size distribution of the material. EDX studies can be used to confirm the elemental composition. Starting precursors for zinc ferrite magnetic fluid are zinc oxide, iron oxide, oleic acid and kerosene.