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Calipers
A caliper (British spelling also calliper, or in plurale tantum sense a pair of calipers) is a device used to measure the dimensions of an object. Many types of calipers permit reading out a measurement on a ruled scale, a dial, or a digital display. Some calipers can be as simple as a compass with inward or outward-facing points, but no scale. The tips of the caliper are adjusted to fit across the points to be measured and the dimension read by measuring between the tips with another measuring tool, such as a ruler. It is used in many fields such as mechanical engineering, metalworking, forestry, woodworking, science and medicine. Plural vs. singular A single tool might be referred to as a "caliper" or as "calipers", like a pair of scissors or glasses (a "plural only" or '' plurale tantum'' form). In colloquial usage, the phrase "pair of verniers" or just " vernier" might refer to a vernier caliper. Colloquially these phrases can also refer to dial calipers, although they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caliper Detail View
A caliper (American and British English spelling differences, British spelling also calliper, or in plurale tantum sense a pair of calipers) is a device used to Measurement, measure the dimensions of an object. Many types of calipers permit reading out a measurement on a ruled scale, a dial, or a digital display. Some calipers can be as simple as a compass (drafting), compass with inward or outward-facing points, but no scale. The tips of the caliper are adjusted to fit across the points to be measured and the dimension read by measuring between the tips with another measuring tool, such as a ruler. It is used in many fields such as mechanical engineering, metalworking, forestry, woodworking, science and medicine. Plural vs. singular A single tool might be referred to as a "caliper" or as "calipers", like a pair of scissors or glasses (a "plural only" or ''plurale tantum'' form). In colloquial usage, the phrase "pair of verniers" or just "Vernier scale, vernier" might refer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metalworking
Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scale: from huge ships, buildings, and bridges down to precise engine parts and delicate jewelry. The historical roots of metalworking predate recorded history; its use spans cultures, civilizations and millennia. It has evolved from shaping soft, native metals like gold with simple hand tools, through the smelting of ores and hot forging of harder metals like iron, up to highly technical modern processes such as machining and welding. It has been used as an industry, a driver of trade, individual hobbies, and in the creation of art; it can be regarded as both a science and a craft. Modern metalworking processes, though diverse and specialized, can be categorized into one of three broad areas known as forming, cutting, or joining proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vernier Scale
A vernier scale, named after Pierre Vernier, is a visual aid to take an accurate measurement reading between two graduation markings on a linear scale by using mechanical interpolation, thereby increasing resolution and reducing measurement uncertainty by using vernier acuity to reduce human estimation error. It may be found on many types of instrument measuring linear or angular quantities, but in particular on a vernier caliper which measures internal or external diameter of hollow cylinders. The vernier is a subsidiary scale replacing a single measured-value pointer, and has for instance ten divisions equal in distance to nine divisions on the main scale. The interpolated reading is obtained by observing which of the vernier scale graduations is coincident with a graduation on the main scale, which is easier to perceive than visual estimation between two points. Such an arrangement can go to a higher resolution by using a higher scale ratio, known as the vernier constant. A v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrometer (device)
A micrometer, sometimes known as a micrometer screw gauge, is a device incorporating a calibrated screw widely used for accurate measurement of components in mechanical engineering and machining as well as most mechanical trades, along with other metrological instruments such as dial, vernier, and digital calipers. Micrometers are usually, but not always, in the form of calipers (opposing ends joined by a frame). The spindle is a very accurately machined screw and the object to be measured is placed between the spindle and the anvil. The spindle is moved by turning the ratchet knob or thimble until the object to be measured is lightly touched by both the spindle and the anvil. Micrometers are also used in telescopes or microscopes to measure the apparent diameter of celestial bodies or microscopic objects. The micrometer used with a telescope was invented about 1638 by William Gascoigne, an English astronomer. History The word ''micrometer'' is a neoclassical coin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xin Dynasty
The Xin dynasty (; ), also known as Xin Mang () in Chinese historiography, was a short-lived Chinese imperial dynasty which lasted from 9 to 23 AD, established by the Han dynasty consort kin Wang Mang, who usurped the throne of the Emperor Ping of Han and the infant "crown prince" Liu Ying. The Xin dynasty ruled for over a decade before it was overthrown by rebels. After Wang's death, the Han dynasty was restored by Liu Xiu, a distant descendant of the Emperor Jing of Han; therefore, the Xin dynasty is often considered an interregnum period of the Han dynasty, dividing it into the Western Han (or "Former Han") and the Eastern Han (or "Later Han"). Etymology Chinese dynasties were typically named after the fief of their founders, and this reading is consistent with Wang Mang's pre-imperial position as Marquess of Xin. In 1950, C.B. Sargent suggested that the name of the dynasty should be read as meaning "new", which J. J. L. Duyvendak rejected out of hand. Chauncey S. Goodr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Era Name
Chinese era names were titles used by various Chinese dynasties and regimes in Imperial China for the purpose of year identification and numbering. The first monarch to adopt era names was the Emperor Wu of Han in 140 BCE, and this system remained the official method of year identification and numbering until the establishment of the Republic of China in 1912 CE, when the era name system was superseded by the Republic of China calendar. Other polities in the Sinosphere— Korea, Vietnam and Japan—also adopted the concept of era name as a result of Chinese politico-cultural influence. Description Chinese era names were titles adopted for the purpose of identifying and numbering years in Imperial China. Era names originated as mottos or slogans chosen by the reigning monarch and usually reflected the political, economic and/or social landscapes at the time. For instance, the first era name proclaimed by the Emperor Wu of Han, ''Jianyuan'' (; lit. "establishing the origin" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wang Mang
Wang Mang () (c. 45 – 6 October 23 CE), courtesy name Jujun (), was the founder and the only emperor of the short-lived Chinese Xin dynasty. He was originally an official and consort kin of the Han dynasty and later seized the throne in 9 CE. The Han dynasty was restored after his overthrow, and his rule marked the separation between the Western Han dynasty (before Xin) and Eastern Han dynasty (after Xin). Traditional Chinese historiography viewed Wang as a tyrant and usurper, while more recently, some historians have portrayed him as a visionary and selfless social reformer. During his reign, he abolished slavery and initiated a land redistribution program. Though a learned Confucian scholar who sought to implement the harmonious society he saw in the classics, his efforts ended in chaos. Wang Mang's late reign saw large-scale peasant rebellions, most notably the revolt of the Red Eyebrows. In October 23 CE, the capital Chang'an was attacked and the imperial pala ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Vernier
Pierre Vernier (19 August 1580 at Ornans, Franche-Comté (at that time ruled by the Spanish Habsburgs, now part of France) – 14 September 1637, same location) was a French mathematician and instrument-inventor. He was the inventor and eponym of the vernier scale used in measuring devices. Life He was born in Ornans, France, in 1580. He was taught science by his father. He became captain and castellan of the castle at Ornans, for the King of Spain. He was also later councillor and director general of economy in the County of Burgundy. In Brussels, in the year 1631, Vernier published his treatise ''La construction, l'usage, et les propriétés du quadrant nouveau de mathématique'', and dedicated it to the Infanta. In it, he described the ingenious device which now bears his name, the vernier scale. To a quadrant with a primary scale in half degrees Vernier proposed to attach a movable sector, thirty-one half degrees in length but divided into thirty equal parts (each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Rome
In modern historiography, ancient Rome refers to Roman civilisation from the founding of the city of Rome in the 8th century BC to the collapse of the Western Roman Empire in the 5th century AD. It encompasses the Roman Kingdom (753–509 BC), Roman Republic (509–27 BC) and Roman Empire (27 BC–476 AD) until the fall of the western empire. Ancient Rome began as an Italic settlement, traditionally dated to 753 BC, beside the River Tiber in the Italian Peninsula. The settlement grew into the city and polity of Rome, and came to control its neighbours through a combination of treaties and military strength. It eventually dominated the Italian Peninsula, assimilated the Greek culture of southern Italy (Magna Grecia) and the Etruscan culture and acquired an Empire that took in much of Europe and the lands and peoples surrounding the Mediterranean Sea. It was among the largest empires in the ancient world, with an estimated 50 to 90 million inhabitants, roughly 20% of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonius (device)
Nonius is a measuring tool used in navigation and astronomy named in honour of its inventor, Pedro Nunes (Latin: Petrus Nonius), a Portuguese author, mathematician and navigator. The nonius was created in 1542 as a system for taking finer measurements on circular instruments such as the astrolabe. The system was eventually adapted into the Vernier scale in 1631 by the French mathematician Pierre Vernier. Technical features The nonius was used to improve the astrolabe's accuracy. This consisted of a number of concentric circles traced on an instrument and dividing each successive one with one fewer divisions than the adjacent outer circle. On a standard scale of 90 degrees, there are an additional 44–45 concentric circles, with each divided into a specific unit size such that a scale unit on position n had an arc of 90/n degrees. Thus, the outermost quadrant would comprise 90° in 90 equal divisions, the next inner would have 89 divisions, the next 88 and so on. When an ang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
