moderate abrasive
51Bicycle brake systems — are used to slow down, or brake a bicycle. There have been various types through history, and several are still in use today.HistoryEarly bicycles such as the high wheeled penny farthing bikes were fitted with spoon brakes. As they were fixed… …
52Wrench — For other uses, see Wrench (disambiguation). A set of chrome vanadium metric wrenches, open at one end, box/ring at the other. This type is commonly known as a combination wrench. A wrench or spanner is a tool used to provide grip and mechanical… …
53Oral ulcer — An oral ulcer (from Latin ulcus ) is the name for the appearance of an open sore inside the mouth caused by a break in the mucous membrane or the epithelium on the lips or surrounding the mouth. The types of oral ulcers are diverse, with a… …
54Ruth Richardson — Infobox Officeholder name=Hon. Ruth Richardson |caption= order=35th Minister of Finance term start=2 November 1990 term end=1993 predecessor=David Caygill successor=Bill Birch primeminister=Jim Bolger birth date=birth date and age|1950|12|13… …
55Ernest Bevin — Infobox Politician name= Ernest Bevin imagesize=250px caption= birth date = 9 March 1881 birth place = Winsford, Somerset, England death place = London, England death date = death date and age|1951|04|14|1881|09|03 office = Secretary of State for …
56Bob Jones, Jr. — Robert Reynolds Jones, Jr. (October 19, 1911 November 12, 1997) was the second president and chancellor of Bob Jones University. Born in Montgomery, Alabama, Jones was the son of Bob Jones, Sr., the university s founder. He served as president… …
57Computer cooling — An OEM AMD heatsink mounted onto a motherboard. Computer cooling is required to remove the waste heat produced by computer components, to keep components within their safe operating temperature limits. Various cooling methods help to improve… …
58Copper(II) oxide — IUPAC name Copper(II) oxide …
59Material properties of diamond — This article addresses the material properties of diamond. For a broader discussion of diamonds, see diamond. For other uses of the word diamond, see diamond (disambiguation). Diamond An octahedral diamond crystal in matrix Gener …
60Air filter — An air filter is a device which removes solid particulates such as dust, pollen, mold, and bacteria from air. Air filters are used in applications where air quality is important, notably in building ventilation systems and in engines, such as… …
