overview. in exothermic welding, aluminium dust reduces the oxide of another metal, most commonly iron oxide, because aluminium is highly reactive.iron iii oxide is commonly used: the products are aluminium oxide, free elemental iron, and a large amount of heat.the reactants are commonly powdered and mixed with a binder to keep the material solid and prevent separation.
deviation refers to the response of the compass to local magnetic fields caused by the presence of iron and electric currents; one can partly compensate for these by careful location of the compass and the placement of compensating magnets under the compass itself. mariners have long known that these measures do not completely cancel deviation .
note that the rusting of iron is a reaction between iron and oxygen that is dissolved in water, not between iron and water. water can be oxidized to emit oxygen gas, but very few oxidants react with water even if their reduction potential is greater than the potential of o 2 /h 2 o. almost all such reactions require a catalyst.
the compass was invented more than 2000 years ago. the first compasses were made of lodestone, a naturally magnetized stone of iron, in han dynasty china 20 bc – 20 ad . the compass was later used for navigation during the chinese song dynasty 960–1279 ad , as described by shen kuo. later compasses were made of iron needles, magnetized by striking them with a lodestone.
a variety of types of electrical transformer are made for different purposes. despite their design differences, the various types employ the same basic principle as discovered in 1831 by michael faraday, and share several key functional parts.
a wet electrostatic precipitator wesp or wet esp operates with water vapor saturated air streams relative humidity . wesps are commonly used to remove liquid droplets such as sulfuric acid mist from industrial process gas streams.
magnetic particles very similar to iron filings are located in the powder cavity. when electricity is applied to the coil, the resulting magnetic flux tries to bind the particles together, almost like a magnetic particle slush. as the electric current is increased, the binding of the particles becomes stronger. the brake rotor passes through .
a common particle used to detect cracks is iron oxide, for both dry and wet systems. wet system particle range in size from less than 0.5 micrometres to 10 micrometres for use with water or oil carriers.
an electrostatic precipitator esp is a filtration device that removes fine particles, like dust and smoke, from a flowing gas using the force of an induced electrostatic charge minimally impeding the flow of gases through the unit. in contrast to wet scrubbers, which apply energy directly to the flowing fluid medium, an esp applies energy .
a nuclear density gauge is a tool used in civil construction and the petroleum industry, as well as for mining and archaeology purposes.it consists of a radiation source that emits a cloud of particles and a sensor that counts the received particles that are either reflected by the test material or pass through it. by calculating the percentage of particles that return to the sensor, the gauge .
a wet cell battery has a liquid electrolyte. other names are flooded cell, since the liquid covers all internal parts, or vented cell, since gases produced during operation can escape to the air. wet cells were a precursor to dry cells and are commonly used as a learning tool for electrochemistry.