DiscoveryImidazole was first synthesized by Heinrich Debus in 1858, but various imidazole derivatives had been discovered as early as the 1840s. His synthesis, as shown below, used glyoxal and formaldehyde in ammonia to form imidazole. This synthesis, while producing relatively low yields, is still used for creating C-substituted imidazoles.In one microwave modification the reactants are benzil, formaldehyde and ammonia in glacial acetic acid...more
Classification as a "hybrid"Because the current Society of Automotive Engineers (SAE) definition of a hybrid vehicle states the vehicle shall have "two or more energy storage systems both of which must provide propulsion power, either together or independently," the company has avoided the use of the term "hybrid" when describing its Voltec designs. Instead GM describes the Volt as an electric vehicle equipped with a "range extending" gasoline...more
Types of current clamp Current transformerThe most common form of current clamp comprises a split ferrite ring. A wire coil is wound round one or both halves, forming the secondary winding of a current transformer. The conductor to be measured forms the primary. Like any transformer this type only works with AC or pulse waveforms, with some examples extending into the megahertz range.This type may also be used to inject current into the conductor, for example in EMC susceptibility testing to induce an interference current. Usually, the injection probe is specifically designed for this purpose. Iron vaneIn the iron vane type, the magnetic flux in the core directly affects a moving iron vane, allowing both AC and DC to be measured, and gives a true RMS value for non-sinusoidal AC waveforms. Due to its physical size it is generally limited to power transmission frequencies up to around 100 Hz.The vane is usually fixed directly to the display mechanism of an analogue (moving pointer) clamp meter. Hall effectThe Hall effect type is more sensitive and is able to measure both DC and AC, in some examples up to the kilohertz (thousands of hertz) range. This type is often used with...more
Common antipruriticsTopical antipruritics in the form of creams and sprays are often available over-the-counter. Oral anti-itch drugs also exist and are usually prescription drugs. The active ingredients usually belong to the following classes:Antihistamines such as diphenhydramine (Benadryl)Corticosteroids such as hydrocortisone topical cream, see...more
TerminologyThe noun "scissors" is treated as a plural noun, and therefore takes a plural verb ("these scissors are"). Alternatively, this tool is also referred to as "a pair of scissors", in which case it (a pair) is singular and therefore takes a singular verb ("this pair of scissors is"). In theory each of the two blades of the tool is a...more
HistoryIn 1643 Evangelista Torricelli, an Italian physicist, showed air was something more than nothing.The balloon was invented by the Luso Brazilian priest (at 45 years of age) Bartolomeu de Gusmo (brother of the Luso Brazilian statesman Alexandre de Gusmo), and the first public exhibition was to the Portuguese Court on August 8, 1709, in the hall of the Casa da ndia in Lisbon.Passarola, Bartolomeu de Gusmo airshipThe rubber balloon was invented by Michael Faraday in 1824; it was inflated with hydrogen and used in his experiments with that element. Rubber balloons were soon after sold for a penny a piece in parks and circuses in America. The more familiar latex balloons of today were first manufactured in London, 1847, by J.G. Ingram,; but mass production did not occur until the 1930s.[citation needed] According to the Reader's Digest, children and adults send up roughly one billion balloons each year in celebration. Balloons are also often part of birthday celebrations.ApplicationsDecoration or entertainmentMain article: Toy balloonParty balloons.Decorative arches made of party balloons.Party balloons are mostly made of natural latex tapped from rubber trees, and can be filled...more
Recently, Shanxi Province Bureau of Quality Supervision inform the third quarter of 2009, some of product quality supervision and spot check results. In luminaries category, 10 batches of product failure. Involved Howley wins, 100 Armada, Hao Sheng,...more
EtymologyFurther information: Chrism and Christian (word)A series of articles onJesus Christ and ChristianityChronology Virgin BirthMinistry Miracles ParablesDeath ResurrectionSecond Coming ChristologyNames and...more
For decades, Wang Daheng the development of China's optical industry has made an outstanding contribution. He was personally involved in the success of China's first furnace melting of optical glass, leading the successful development of large-scale...more
HistoryThe original "Pep Boys" were Emanuel "Manny" Rosenfeld, Maurice "Moe" Strauss, Graham "Jack" Jackson and Moe Radavitz, four friends who pooled $800 in 1921 to open a single auto parts store. They dubbed it "Pep Auto Supplies" after noticing a...more
As a pigmentThis xanthophyll, like its sister compound zeaxanthin, has primarily been used as a natural colorant due to its orange-red color. Lutein absorbs blue light and therefore appears yellow at low concentrations and orange-red at high...more