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Equation Clock
An equation clock is a mechanical clock which includes a mechanism that simulates the equation of time, so that the user can read or calculate solar time, as would be shown by a sundial. The first accurate clocks, controlled by pendulums, were patented by Christiaan Huyghens in 1657. For the next few decades, people were still accustomed to using sundials, and wanted to be able to use clocks to find solar time. Equation clocks were invented to fill this need. Early equation clocks have a pointer that moves to show the equation of time on a dial or scale. The clock itself runs at constant speed. The user calculates solar time by adding the equation of time to the clock reading. Later equation clocks, made in the 18th Century, perform the compensation automatically, so the clock directly shows solar time. Some of them also show Local mean time, mean time, which is often called "clock time". Simulation mechanisms All equation clocks include a mechanism that simulates the equation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1591 Equation Clock Jeh
Events January–June * March 13 – Battle of Tondibi: In Mali, forces sent by the Saadi dynasty ruler of Morocco, Ahmad al-Mansur, and led by Judar Pasha, defeat the Songhai Empire, fractured Songhai Empire, despite being outnumbered by at least five to one. * April 10 – English people, English merchant James Lancaster sets off on a voyage to the East Indies. * April 21 – Japanese Japanese tea ceremony, tea-master Sen no Rikyū commits seppuku, on the order of Toyotomi Hideyoshi. * May 15 – In Tsardom of Russia, Russia, Tsarevich Dmitry Ivanovich of Russia (born 1582), Tsarevich Dimitri, son of Ivan the Terrible, is found dead in mysterious circumstances, at the palace in Uglich. The official explanation is that he has cut his own throat during an epileptic seizure. Many believe he has been murdered by his rival, Boris Godunov, who becomes tsar. * May 24 – Sir John Norris (soldier), John Norreys, with an expeditionary force sent by Queen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
External Links
An internal link is a type of hyperlink on a web page to another page or resource, such as an image or document, on the same website or domain. Hyperlinks are considered either "external" or "internal" depending on their target or destination. Generally, a link to a page outside the same domain or website is considered external, whereas one that points at another section of the same web page or to another page of the same website or domain is considered internal. These definitions become clouded, however, when the same organization operates multiple domains functioning as a single web experience, e.g. when a secure commerce website is used for purchasing things displayed on a non-secure website. In these cases, links that are "external" by the above definition can conceivably be classified as "internal" for some purposes. Ultimately, an internal link points to a web page or resource in the same root directory. Similarly, seemingly "internal" links are in fact "external" for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clock
A clock or a timepiece is a device used to measure and indicate time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month and the year. Devices operating on several physical processes have been used over the millennia. Some predecessors to the modern clock may be considered as "clocks" that are based on movement in nature: A sundial shows the time by displaying the position of a shadow on a flat surface. There is a range of duration timers, a well-known example being the hourglass. Water clocks, along with the sundials, are possibly the oldest time-measuring instruments. A major advance occurred with the invention of the verge escapement, which made possible the first mechanical clocks around 1300 in Europe, which kept time with oscillating timekeepers like balance wheels., pp. 103–104., p. 31. Traditionally, in horology, the term ''clock'' was used for a stri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sundial
A sundial is a horological device that tells the time of day (referred to as civil time in modern usage) when direct sunlight shines by the apparent position of the Sun in the sky. In the narrowest sense of the word, it consists of a flat plate (the ''dial'') and a gnomon, which casts a shadow onto the dial. As the Sun appears to move through the sky, the shadow aligns with different hour-lines, which are marked on the dial to indicate the time of day. The ''style'' is the time-telling edge of the gnomon, though a single point or ''nodus'' may be used. The gnomon casts a broad shadow; the shadow of the style shows the time. The gnomon may be a rod, wire, or elaborately decorated metal casting. The style must be parallel to the axis of the Earth's rotation for the sundial to be accurate throughout the year. The style's angle from horizontal is equal to the sundial's geographical latitude. The term ''sundial'' can refer to any device that uses the Sun's altitude or azimut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Tracker
A solar tracker is a device that orients a payload toward the Sun. Payloads are usually solar panels, parabolic troughs, fresnel reflectors, lenses or the mirrors of a heliostat. For flat-panel photovoltaic systems, trackers are used to minimize the angle of incidence between the incoming sunlight and a photovoltaic panel, sometimes known as the cosine error. Reducing this angle increases the amount of energy produced from a fixed amount of installed power generating capacity. In standard photovoltaic applications, it was predicted in 2008-2009 that trackers could be used in at least 85% of commercial installations greater than one megawatt from 2009 to 2012. As the pricing, reliability and performance of single-axis trackers have improved, the systems have been installed in an increasing percentage of utility-scale projects. According to data from WoodMackenzie/GTM Research, global solar tracker shipments hit a record 14.5 gigawatts in 2017. This represents growth of 32 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential (mechanical Device)
A differential is a gear train with three drive shafts that has the property that the rotational speed of one shaft is the average of the speeds of the others, or a fixed multiple of that average. Functional description The following description of a differential applies to a traditional rear-wheel-drive car or truck with an open or limited slip differential combined with a reduction gearset using bevel gears (these are not strictly necessary; see spur-gear differential): Thus, for example, if the car is making a turn to the right, the main ring gear may make 10 full rotations. During that time, the left wheel will make more rotations because it has farther to travel, and the right wheel will make fewer rotations as it has less distance to travel. The sun gears (which drive the axle half-shafts) will rotate at different speeds relative to the ring gear (one faster, one slower) by, say, 2 full turns each (4 full turns relative to each other), resulting in the left wheel mak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog Computer
An analog computer or analogue computer is a type of computer that uses the continuous variation aspect of physical phenomena such as electrical, mechanical, or hydraulic quantities (''analog signals'') to model the problem being solved. In contrast, digital computers represent varying quantities symbolically and by discrete values of both time and amplitude (digital signals). Analog computers can have a very wide range of complexity. Slide rules and nomograms are the simplest, while naval gunfire control computers and large hybrid digital/analog computers were among the most complicated. Complex mechanisms for process control and protective relays used analog computation to perform control and protective functions. Analog computers were widely used in scientific and industrial applications even after the advent of digital computers, because at the time they were typically much faster, but they started to become obsolete as early as the 1950s and 1960s, although they remaine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the interval of time between events, so the period is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times a minute (2 hertz), the period, —the interval at which the beats repeat—is half a second (60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. Definitions and units For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term ''frequency'' is defined as the number of cycles or vibrations per unit of time. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coupling (physics)
In physics, two objects are said to be coupled when they are interacting with each other. In classical mechanics, coupling is a connection between two oscillating systems, such as pendulums connected by a spring. The connection affects the oscillatory pattern of both objects. In particle physics, two particles are coupled if they are connected by one of the four fundamental forces. Wave mechanics Coupled harmonic oscillator If two waves are able to transmit energy to each other, then these waves are said to be "coupled." This normally occurs when the waves share a common component. An example of this is two pendulums connected by a spring. If the pendulums are identical, then their equations of motion are given by m\ddot = -mg\frac - k(x-y) m\ddot = -mg \frac + k(x-y) These equations represent the simple harmonic motion of the pendulum with an added coupling factor of the spring. This behavior is also seen in certain molecules (such as CO2 and H2O), wherein two of the atoms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Striking Clock
A striking clock is a clock that sounds the hours audibly on a bell or gong. In 12-hour striking, used most commonly in striking clocks today, the clock strikes once at 1:00 am, twice at 2:00 am, continuing in this way up to twelve times at 12:00 mid-day, then starts again, striking once at 1:00 pm, twice at 2:00 pm, up to twelve times at 12:00 midnight. The striking feature of clocks was originally more important than their clock faces; the earliest clocks struck the hours, but had no dials to enable the time to be read. The development of mechanical clocks in 12th century Europe was motivated by the need to ring bells upon the canonical hours to call the community to prayer. The earliest known mechanical clocks were large striking clocks installed in towers in monasteries or public squares, so that their bells could be heard far away. Though an early striking clock in Syria was a 12-hour clock, many early clocks struck up to 24 strokes, particularly in Italy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combining Lever
A whippletree, or whiffletree, is a mechanism to distribute force evenly through linkages. It is also referred to as an equalizer, leader bar, or double tree. It consists of a bar pivoted at or near the centre, with force applied from one direction to the pivot and from the other direction to the tips. Several whippletrees may be used in series to distribute the force further, such as to simulate pressure over an area as when applying loading to test airplane wings. Whippletrees may be used either in compression or tension. They were also used for subtraction and addition calculations in mechanical computers. Tension whippletrees are used in artful hung mobiles, such as those by artist Alexander Calder. Draught whippletrees Whippletrees are used in tension to distribute forces from a point load to the traces of draught animals (the traces are the chains or straps on each side of the harness, on which the animal pulls). For these, the whippletree consists of a loose horizontal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clock
A clock or a timepiece is a device used to measure and indicate time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month and the year. Devices operating on several physical processes have been used over the millennia. Some predecessors to the modern clock may be considered as "clocks" that are based on movement in nature: A sundial shows the time by displaying the position of a shadow on a flat surface. There is a range of duration timers, a well-known example being the hourglass. Water clocks, along with the sundials, are possibly the oldest time-measuring instruments. A major advance occurred with the invention of the verge escapement, which made possible the first mechanical clocks around 1300 in Europe, which kept time with oscillating timekeepers like balance wheels., pp. 103–104., p. 31. Traditionally, in horology, the term ''clock'' was used for a stri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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