Currents from wires

Electrolytic corrosion may also occur on the inside of cable sheaths by the passage of current from the cable sheath to the wire . 

Although at the time of his early inventions Dr. Schoop envisaged that an electric arc could be used to produce the molten metal for spraying, forty years passed before the method became commercially important. Then, in Germany, Russia and Japan tools were made based on the arc. Although in Japan alternating current is used, the noise is nearly intolerable and elsewhere direct current from motor generators is employed. The fundamental idea is simple two wires, carefully insulated from each other, are advanced to meet at a point where an arc is formed, immediately in advance of a Jet... 

If large electrical currents, as in the case of superconducting magnets, must be carried to low temperature, Cu wires are in most cases used to carry currents from room temperature to 4 K. In Tables 4.1 and 4.2, data of electrical and thermal conductivity of some commonly used materials are reported. 

The hot-wire anemometer can, with suitable cahbration, accurately measure velocities from about 0.15 m/s (0.5 fl/s) to supersonic velocities and detect velocity fluctuations with frequencies up to 200,000 Hz. Eairly rugged, inexpensive units can be built for the measurement of mean velocities in the range of 0.15 to 30 m/s (about 0.5 to 100 ft/s). More elaborate, compensated units are commercially available for use in unsteady flow and turbulence measurements. In cahbrating a hotwire anemometer, it is preferable to use the same gas, temperature, and pressure as will be encountered in the intended apphcation. In this case the quantity I RJAt can be plotted against /v, where I = hot-wire current, = hot-wire resistance. At = difference between the wire temperature and the gas bulk temperature, and V = mean local velocity. A procedure is given by Wasan and Raid [Am. Inst. Chem. Eng. J., 17, 729-731 (1971)] for use when it is impractical to calibrate with the same gas composition or conditions of temperature and pressure. Andrews, Rradley, and Hundy [Int. J. Heat Mass Transfer, 15, 1765-1786 (1972)] give a cahbration correlation for measurement... 

Electricity is so prevalent in modern society that an electrical power failure, such as the blackout in the northeastern part of the United States and parts of Canada on August 14, 2003, causes a major inconvenience. People rely on electricity to heat and light their homes, to operate many different kinds of appliances and motors, and to run subways, commuter trains and similar transportation systems. There is also a great deal of reliance on batteries, which store electricity and allow the portability of small devices that would otherwise require the use of wires to carry the required current from a generator. 

Arrangement of the apparatus. This is shown diagrammatically in Fig. 53. The alternating current from the induction coil I flows to the contact C and to the wire joining the rheostat R with one of the plates of the cell X, there dividing into two currents, one flowing through the known resistance R and the part a of the wire and the other, by means of two copper wires... 

Common mode noise is present equally and in phase in each current carrying wire with respect to a ground plane or circuit. Common mode noise can be caused by radiated emission from a source of EMI. Common mode noise can also couple from one circuit to another by inductive or capacitive means. Lightning discharges may also produce common mode noise in power wiring,... 

In order to avoid interfering magnetic noise which rises from cables conducting large currents these wires should be twisted. In case that the current in the two wires is equal and of opposite direction the magnetic field would then cancel. 

Equation (19) implies that the net current from site n— 1 to site n on wire K is... 

The method most generally applied to the isolation of lithium is based on the decomposition of the fused chloride by electrolysis, modifications in practical details having been introduced by various experimenters. Bunsen and Matthiessen1 passed the current from six Bunsen cells through the fused chloride contained in a porcelain crucible, with a carbon rod as anode and an iron wire as cathode. Troost employed a similar method. Guntz2 mixed lithium chloride with potassium chloride, but his product contained 1-3 per cent, of potassium. His current was 10 amperes at 20 volts, with a cathode of iron wire 3-4 mm. in diameter. Borchers3 added chlorides of other alkali-metals and alkaline-earth-metals and a small proportion of ammonium chloride, and employed a current density of 10 amperes per 100 sq. cm. Tucker 4 electrolyzed the chloride without the addition of other material. 

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