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Ruler
A ruler, sometimes called a rule, line gauge, or scale, is a device used in geometry and technical drawing, as well as the engineering and construction industries, to measure distances or draw straight lines. Variants Rulers have long been made from different materials and in multiple sizes. Some are wooden. Plastics have also been used since they were invented; they can be molded with length markings instead of being scribed. Metal is used for more durable rulers for use in the workshop; sometimes a metal edge is embedded into a wooden desk ruler to preserve the edge when used for straight-line cutting. in length is useful for a ruler to be kept on a desk to help in drawing. Shorter rulers are convenient for keeping in a pocket. Longer rulers, e.g., , are necessary in some cases. Rigid wooden or plastic yardsticks, 1 yard long, and meter sticks, 1 meter long, are also used. Classically, long measuring rods were used for larger projects, now superseded by ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compass And Straightedge
In geometry, straightedge-and-compass construction – also known as ruler-and-compass construction, Euclidean construction, or classical construction – is the construction of lengths, angles, and other geometric figures using only an idealized ruler and a pair of compasses. The idealized ruler, known as a straightedge, is assumed to be infinite in length, have only one edge, and no markings on it. The compass is assumed to have no maximum or minimum radius, and is assumed to "collapse" when lifted from the page, so may not be directly used to transfer distances. (This is an unimportant restriction since, using a multi-step procedure, a distance can be transferred even with a collapsing compass; see compass equivalence theorem. Note however that whilst a non-collapsing compass held against a straightedge might seem to be equivalent to marking it, the neusis construction is still impermissible and this is what unmarked really means: see Markable rulers below.) More formally, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Measuring Rod
A measuring rod is a tool used to physically measure lengths and survey areas of various sizes. Most measuring rods are round or square sectioned; however, they can also be flat boards. Some have markings at regular intervals. It is likely that the measuring rod was used before the line, chain or steel tapes used in modern measurement. History Ancient Sumer The oldest preserved measuring rod is a copper-alloy bar which was found by the German Assyriologist Eckhard Unger while excavating at Nippur (pictured below). The bar dates from c. 2650 BC. and Unger claimed it was used as a measurement standard. This irregularly formed and irregularly marked ''graduated rule'' supposedly defined the ''Sumerian cubit'' as about , although this does not agree with other evidence from the statues of Gudea from the same region, five centuries later. Ancient India Rulers made from ivory were in use by the Indus Valley Civilization in what today is Pakistan, and in some parts of Western Indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle Trisection
Angle trisection is a classical problem of straightedge and compass construction of ancient Greek mathematics. It concerns construction of an angle equal to one third of a given arbitrary angle, using only two tools: an unmarked straightedge and a compass. Pierre Wantzel proved in 1837 that the problem, as stated, is impossible to solve for arbitrary angles. However, although there is no way to trisect an angle ''in general'' with just a compass and a straightedge, some special angles can be trisected. For example, it is relatively straightforward to trisect a right angle (that is, to construct an angle of measure 30 degrees). It is possible to trisect an arbitrary angle by using tools other than straightedge and compass. For example, neusis construction, also known to ancient Greeks, involves simultaneous sliding and rotation of a marked straightedge, which cannot be achieved with the original tools. Other techniques were developed by mathematicians over the centuries. Becaus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steel Ruler Closeup
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant typically need an additional 11% chromium. Because of its high tensile strength and low cost, steel is used in buildings, infrastructure, tools, ships, trains, cars, machines, electrical appliances, weapons, and rockets. Iron is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic. The interaction of the allotropes of iron with the alloying elements, primarily carbon, gives steel and cast iron their range of unique properties. In pure iron, the crystal structure has relatively little resistance to the iron atoms slipping past one another, and so pure iron is quite ductile, or soft and easily formed. In steel, small amounts of carbon, other ele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distance Measurement
Length measurement, distance measurement, or range measurement (ranging) refers to the many ways in which length, distance, or range can be measured. The most commonly used approaches are the rulers, followed by transit-time methods and the interferometer methods based upon the speed of light. For objects such as crystals and diffraction gratings, diffraction is used with X-rays and electron beams. Measurement techniques for three-dimensional structures very small in every dimension use specialized instruments such as ion microscopy coupled with intensive computer modeling. Standard rulers The ruler the simplest kind of length measurement tool: lengths are defined by printed marks or engravings on a stick. The metre was initially defined using a ruler before more accurate methods became available. Gauge blocks are a common method for precise measurement or calibration of measurement tools. For small or microscopic objects, microphotography where the length is calibrated us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agate (typography)
An agate ( US) or ruby ( UK) is a unit of typographical measure. It is 5.5 typographical points, or about inch (1.94 mm). It can refer either to the height of a line of type or to a font that is 5.5 points. An is commonly used to display statistical data or legal notices in newspapers. It is considered to be the smallest point size that can be printed on newsprint and remain legible. Due to the small size of agate compared to typical newspaper body text that might be 8 to 10 points and due to its use for statistical, stock, racing or other table uses, the term "agate" may also refer to tables and texts using this point size. The general description "agate" refers to the collection of miscellaneous tables, stock tables, horse racing and sports tables and so forth that may be in a newspaper. From the ''American Dictionary of Printing and Bookmaking'' (1894): See also * Traditional point-size names Fonts originally consisted of a set of moveable type letterpunches pur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pica (typography)
The pica is a typographic unit of measure corresponding to approximately of an inch, or from to of a foot. One pica is further divided into 12 points. In printing, three pica measures are used: * The French pica of 12 Didot points (also called cicero) generally is: 12 × 0.376 = . * The American pica of . It was established by the United States Type Founders' Association in 1886. In TeX one pica is of an inch. * The contemporary computer PostScript pica is exactly of an inch or of a foot, i.e. 4.2 mm or 0.1 in. Publishing applications such as Adobe InDesign and QuarkXPress represent pica measurements with whole-number picas left of a lower-case ''p'', followed by the points number, for example: 5p6 represents 5 picas and 6 points, or 5 picas. Cascading Style Sheets (CSS) defined by the World Wide Web Consortium use pc as the abbreviation for pica ( of an inch), and pt for point ( of an inch). The pica is also used in measuring the font capacity and is applied in the pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point (typography)
In typography, the point is the smallest unit of measure. It is used for measuring font size, leading, and other items on a printed page. The size of the point has varied throughout printing's history. Since the 18th century, the size of a point has been between 0.18 and 0.4 millimeters. Following the advent of desktop publishing in the 1980s and 1990s, digital printing has largely supplanted the letterpress printing and has established the DTP point (DeskTop Publishing point) as the ''de facto'' standard. The DTP point is defined as of an international inch () and, as with earlier American point sizes, is considered to be of a pica. In metal type, the point size of the font describes the height of the metal body on which the typeface's characters were cast. In digital type, letters of a font are designed around an imaginary space called an '' em square''. When a point size of a font is specified, the font is scaled so that its em square has a side length of that parti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waist
The waist is the part of the abdomen between the rib cage and hips. On people with slim bodies, the waist is the narrowest part of the torso. ''Waistline'' refers to the horizontal line where the waist is narrowest, or to the general appearance of the waist. Structure Because of this and because the waist is often synonymous with the stomach, one can become confused as to the exact location of the waist. Another confusing factor is that the waistline differs on different people. A study showed that self-reported measurements as opposed to measurement done by a technician, underestimated waist circumference and this underestimation increased with increased body size. In the study, waist circumference measured at the level of the umbilicus was larger than that measured at the natural waist. To locate the natural waistline, one need simply stand upright and then tilt over to the side keeping the legs and hips straight. Where the torso creases is the natural waistline. Waist me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nippur Cubit
Nippur ( Sumerian: ''Nibru'', often logographically recorded as , EN.LÍLKI, "Enlil City;"The Cambridge Ancient History: Prolegomena & Prehistory': Vol. 1, Part 1. Accessed 15 Dec 2010. Akkadian: ''Nibbur'') was an ancient Sumerian city. It was the special seat of the worship of the Sumerian god Enlil, the "Lord Wind", ruler of the cosmos, subject to An alone. Nippur was located in modern Nuffar in Afak, Al-Qādisiyyah Governorate, Iraq (roughly 200 km south of Baghdad). Occupation at the site extended back to the Uruk period, the Ubaid period, and the Jemdet Nasr period. History Nippur never enjoyed political hegemony in its own right, but its control was crucial, as it was considered capable of conferring the overall "kingship" on monarchs from other city-states. It was distinctively a sacred city, important from the possession of the famous Ekur temple of Enlil. Ninurta also had his main cult center, the E-shumesha temple, in the city-state. According to the ''Tummal Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rangefinding Telemeter
A rangefinder (also rangefinding telemeter, depending on the context) is a device used to measure distances to remote objects. Originally optical devices used in surveying, they soon found applications in other fields, such as photography and in the military. They were specially useful for finding the range of a target, such as in naval gunnery and anti-aircraft artillery. The word ''telemeter'' is derived . Designs The first rangefinder telemeter was invented by James Watt in 1769 and put to use in 1771 in surveying canals. Watt called his instrument a micrometer, a term now used with a different meaning in engineering (the micrometer screw gauge). It consisted of two parallel hairs in the focal plane of a telescope eyepiece crossing an upright hair. At the point to be measured, two sliding targets on a surveyor's rod were adjusted to align with the hairs in the telescope. The distance to the rod could then be determined from the distance between the targets on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
