Quadrant Model of Reality: Quadrant Model of Reality Book 10 Science Physics and Chemistry

Similar to my previous Quadrant Model books, this Quadrant Model book will be organized and designed around the four fields of inquiry.

Science

Physics

Chemistry

Biology

Psychology

Sociology

Religion

Buddhism

Christianity

Islam

Hinduism

Judaism

Other

Art

Painting

Music

Dance

Literature

Cinema

Philosophy

Science chapter

QMRWhen making observations, scientists look through telescopes, study images on electronic screens, record meter readings, and so on. Generally, on a basic level, they can agree on what they see, e.g., the thermometer shows 37.9 degrees C. But, if these scientists have different ideas about the theories that have been developed to explain these basic observations, they may disagree about what they are observing. For example, before Albert Einstein's general theory of relativity, observers would have likely interpreted the image at left as five different objects in space. In light of that theory, however, astronomers will tell you that is actually only two objects, one in the center and four different images of the same object around the sides. Alternatively, if other scientists suspect that something is wrong with the telescope and only one object is actually being observed, they are operating under yet another theory. Observations that cannot be separated from theoretical interpretation are said to be theory-laden.[16]

All observation involves both perception and cognition. That is, one does not make an observation passively, but rather is actively engaged in distinguishing the phenomenon being observed from surrounding sensory data. Therefore, observations are affected by one's underlying understanding of the way in which the world functions, and that understanding may influence what is perceived, noticed, or deemed worthy of consideration. In this sense, it can be argued that all observation is theory-laden.[16]

QMRIn "A Psychological Approach to the Doctrine of the Trinity",[6] again by tenet #1 Jung interprets the Father as the self, the source of energy within the psyche; the Son as an emergent structure of consciousness that replaces the self-alienated ego; and the Holy Spirit as a mediating structure between the ego and the self. However, Jung believed that the psyche moves toward completion in fours (made up of pairs of opposites), and that therefore (using tenet #3 above) the Christian formulation of the Trinity would give way to a quaternity by including missing aspects (e.g. the feminine and evil). (This analysis prompted Jung to send a congratulatory note to Pope Pius XII in 1950 upon the adoption of the doctrine of the Assumption of the Blessed Virgin Mary, to wit completing the quaternity.)

QMRRobert L. Moore, Jungian analyst and professor of psychology and religion, cites Jesus Christ as expressing four archetypal patterns found in the male psyche: the Warrior (in wrestling with his inner demons in the desert and at Gethsemane);[12] the Lover (in radicalizing the commandment to love our neighbors);[13] the Magician (in changing water to wine, feeding the thousands, and healing the sick);[14] and the King (in generating the Kingdom of God, and in identifying himself with the way to the Father).

QMRAntonia Anna "Toni" Wolff (18 September 1888 — 21 March 1953) was a Swiss Jungian analyst and a close associate of Carl Jung. During her analytic career Toni Wolff published relatively little under her own name, but she helped Jung identify, define, and name some of his best-known concepts including anima, animus, and persona.[1] Her best-known paper was an essay on four "types" or aspects of the feminine psyche: the Amazon, the Mother, the Hetaira (or Courtesan), and the Medial (or mediumistic) Woman.[2]

Physics Chapter

QMRHindu given names[edit]

Hindu astrologers (see Jyotisha) teach that when a child is born, they should be given an auspicious first name which will correspond to the child's Nakshatra. The technique for deducing the name is to see which nakshatra the Moon is in at the moment of birth; this gives four possible sounds. A refinement is to pick one sound out of that four that relates to the Pada or division of the Nakshatra. Each Nakshatra has four Padas and four sounds and each Pada is of equal width. The Moon remains in each Nakshatra for approximately one day.

A further refinement or opportunity is to instead use the Nakshatra that the ascendent resides in at birth. The same broad choice of sounds and Padas apply, but now the sounds change roughly every 15 minutes. The ascendent passes through all 27 Nakshatras every 24 hours, being in each one for 53 and a third minutes of time, and is in a Pada for 13 and a third minutes of time. By using the ascendent's nakshatra, instead of the Moon's nakshatra leads more to comfort of the Self, rather than comfort of the mother. This second approach is only really applicable if intuitively the Moon approach does not feel right.

QMRThe four central stars in Hercules, Epsilon (ε Her), Zeta (ζ Her), Eta (η Her), and Pi (π Her), form the well-known Keystone.[4]

QMRThe Terebellum is a small quadrilateral of four faint stars (Omega, 59, 60, 62) in Sagittarius' hindquarters.[13]

Four other stars (Beta — Miaplacidus, Upsilon, Theta, and Omega Carinae) form a well-shaped diamond — the Diamond Cross.[14]

QMRAlpha and Beta Centauri are the Southern Pointers leading to the Southern Cross[16] and thus helping to distinguish Crux from the False Cross.

QMRThe False Cross is composed of the four stars Delta and Kappa Velorum (δ and κ Vel) and Epsilon and Iota Carinae (ε and ι Car).[14] Although its component stars are not quite as bright as those of the Southern Cross, it is somewhat larger and better shaped than the Southern Cross, for which it was often mistaken by ships' navigators.

The fine point of what constitutes an asterism may be seen in two examples. Theta Orionis (θ Ori) is embedded in, and illuminates, the Orion Nebula (M42). Looked at telescopically, it resolved into four stars arranged in a trapezoid, and they were nicknamed the Trapezium. The asterism retained this name even when it was discovered that there were yet more stars in the group. However, it has since been determined that the Orion Nebula is a stellar nursery and that the Trapezium is actually an Open Cluster. Thus it is no longer an asterism. On the other hand, M73 in Aquarius, which was thought to be an Open Cluster, turns out to be composed of unrelated stars, and may now be considered to be an asterism.

QMR. One reason hypothesized why the US won WWII was Eisenhower had only four commanders under him. One for the navy air force the US army group and the British army group, whereas Hitler had a very complicated structure under him. The US had a very clean orb chart with well defined responsibilities with the four commanders under Eisenhower, whereas the the Germans had a very complicated structure that did not work well.

QMR Indian war elephants carried four men. Two shot from the sides and one shot from behind and one guided the elephant

QMREthical categories[edit]

Another possible system for categorizing different schools of thought on war can be found in the Stanford Encyclopedia of Philosophy (see external links, below), based on ethics. The SEP describes three major divisions in the ethics of war: the Realist, the Pacifist, and the Just War Theory. In a nutshell:

Realists will typically hold that systems of morals and ethics which guide individuals within societies cannot realistically be applied to societies as a whole to govern the way they, as societies, interact with other societies. Hence, a state's purposes in war is simply to preserve its national interest. This kind of thinking is similar to Machiavelli's philosophy, and Thucydides and Hobbes may also fall under this category.

Pacifism however, maintains that a moral evaluation of war is possible, and that war is always found to be immoral. Generally, there are two kinds of modern secular pacifism to consider: (1) a more consequentialist form of pacifism (or CP), which maintains that the benefits accruing from war can never outweigh the costs of fighting it; and (2) a more deontological form of pacifism (or DP), which contends that the very activity of war is intrinsically wrong, since it violates foremost duties of justice, such as not killing human beings. Henry Ford and others were famous advocates of pacifistic diplomatic methods instead of war.

Nonviolence also holds that a moral evaluation of war is a duty, and that war is always found to be immoral. Mohandas K. Gandhi, Martin Luther King and Leo Tolstoy were all famous advocates of power of truth, lawfulness, soft power, nonviolent resistance and civil disobedience methods instead of war and to prevent war. Gandhi said he disliked more cowardice than violence.

Just War Theory, along with pacifism, holds that morals do apply to war. However, unlike pacifism, according to Just War Theory it is possible for a war to be morally justified. The concept of a morally justified war underlies much of the concept International Law, such as the Geneva Conventions. Aristotle, Cicero, Augustine, Aquinas, and Hugo Grotius are among the philosophers who have espoused some form of a just war philosophy. One common Just War Theory evaluation of war is that war is only justified if 1.) waged in a state or nation's self-defense, or 2.) waged in order to end gross violations of human rights. Political philosopher John Rawls advocated these criteria as justification for war.

QMRTrapezium Cluster

From Wikipedia, the free encyclopedia

(Redirected from Trapezium (astronomy))

This article is about the open cluster. For other uses, see Trapezium.

Trapezium

Trapezium cluster optical and infrared comparison.jpg

Trapezium in optical (left) and infrared light (right) from Hubble. NASA photo.

Observation data (J2000 epoch)

Constellation Orion

Right ascension 05h 35.4m

Declination −05° 27′

Distance 1,344±20 ly (412 pc[1])

Apparent magnitude (V) 4.0

Apparent dimensions (V) 47 (seconds of arc)

Physical characteristics

Mass ? M☉

Radius 10 ly

Estimated age 3 × 105 years

See also: Open cluster, List of open clusters

The Trapezium or Orion Trapezium Cluster, also known by its Bayer designation of Theta1 Orionis, is a tight open cluster of stars in the heart of the Orion Nebula, in the constellation of Orion. It was discovered by Galileo Galilei. On February 4, 1617 he sketched three of the stars (A, C, D), but missed the surrounding nebulosity.[2][3][4] The fourth component (B) was identified by several observers in 1673, and several more components were discovered later, for a total of eight by 1888. Subsequently several of the stars were determined to be binaries. Telescopes of amateur astronomers from about 5 inch aperture can resolve six stars under good seeing conditions.[5]

The Trapezium is a relatively young cluster that has formed directly out of the parent nebula. The five brightest stars are on the order of 15-30 solar masses in size. They are within a diameter of 1.5 light-years of each other and are responsible for much of the illumination of the surrounding nebula. The Trapezium may be a sub-component of the larger Orion Nebula Cluster, a grouping of about 2,000 stars within a diameter of 20 light-years.

It is most readily identifiable by the asterism of four relatively bright stars. The four are often identified as A, B, C, and D in order of increasing right ascension. The brightest of the four stars is C, or Theta1 Orionis C, with an apparent magnitude of 5.13. Both A and B have been identified as eclipsing binaries.

Infrared images of the Trapezium are better able to penetrate the surrounding clouds of dust, and have located many more stellar components. About half the stars within the cluster have been found to contain evaporating circumstellar disks, a likely precursor to planetary formation. In addition, brown dwarfs and low-mass runaway stars have been identified.

Possible black hole[edit]

A 2012 paper suggests an intermediate mass black hole with a mass >100 times larger than that of the Sun may be present within the Trapezium, something that could explain the large velocity dispersion of the stars of the clust

QMRRevised Bayer designations[edit]

Ptolemy designated four stars as "border stars", each shared by two constellations: Alpheratz (in Andromeda and Pegasus), Elnath (in Taurus and Auriga), Nu Boötis (in Boötes and Hercules), and Fomalhaut (in Piscis Austrinus and Aquarius).[6]:p. 23 Bayer assigned the first three of these stars a Greek letter from both constellations: Alpha Andromedae = Delta Pegasi, Beta Tauri = Gamma Aurigae, and Nu Boötis = Psi Herculis. (He catalogued Fomalhaut only once, as Alpha Piscis Austrini.) When the International Astronomical Union (IAU) assigned definite boundaries to the constellations in 1930, it declared that stars and other celestial objects can belong to only one constellation. Consequently, the redundant second designation in each pair above has dropped out of use.

QMRThe Terebellum, by Ptolemy called τετράπλευρον (/tetrápleuron/), is a quadrilateral of stars in the constellation Sagittarius. It is formed of four 4th magnitude stars, all within two degrees of each other

Omega Sagittarii, at the northeast corner.

59 Sagittarii or b Sagittarii, at the southeast corner.

60 Sagittarii or A Sagittarii, at the northwest corner.

62 Sagittarii or c Sagittarii, at the southwest corner.

The stars are not gravitationally bound to each other as they are at different distances from the Earth.

QMRClassical types[edit]

Objects named nebulae belong to four major groups. Before their nature was understood, galaxies ("spiral nebulae") and star clusters too distant to be resolved as stars were also classified as nebulae, but no longer are.

H II regions, large diffuse nebulae containing ionized hydrogen

Planetary nebulae

Supernova remnant (e.g., Crab Nebula)

Dark nebula

Not all cloud-like structures are named nebulae; Herbig–Haro objects are an example

Diffuse nebulae[edit]

The Carina Nebula is a diffuse nebula

Most nebulae can be described as diffuse nebulae, which means that they are extended and contain no well-defined boundaries.[17] In visible light these nebulae may be divided into emission and reflection nebulae. Emission nebulae emit spectral line radiation from ionized gas (mostly ionized hydrogen);[18] they are often called HII regions (the term "HII" is used in professional astronomy to refer to ionized hydrogen).

Reflection nebulae themselves do not emit significant amounts of visible light, but are near stars and reflect light from them.[18] Similar nebulae not illuminated by stars do not exhibit visible radiation, but may be detected as opaque clouds blocking light from luminous objects behind them; they are called "dark nebulae".[18]

Although these nebulae have different visibility at optical wavelengths, they are all bright sources of infrared emission, chiefly from dust within the nebulae

Planetary nebulae[edit]

Four different planetary nebulae

Main article: Planetary nebula

Planetary nebulae form from the gaseous shells that are ejected from low-mass asymptotic giant branch stars when they transform into white dwarfs.[18] They are emission nebulae with spectra similar to those of emission nebulae found in star formation regions.[18] Technically they are HII regions, because most hydrogen will be ionized, but they are denser and more compact than the nebulae in star formation regions.[18] Planetary nebulae were given their name by the first astronomical observers who became able to distinguish them from planets, who tended to confuse them with planets, of more interest to them. Our Sun is expected to spawn a planetary nebula about 12 billion years after its formation.[19]

Protoplanetary nebula[edit]

Main article: Protoplanetary nebula

A protoplanetary nebula (PPN) is an astronomical object which is at the short-lived episode during a star's rapid stellar evolution between the late asymptotic giant branch (LAGB) phase and the following planetary nebula (PN) phase.[20] During the AGB phase, the star undergoes mass loss, emitting a circumstellar shell of hydrogen gas. When this phase comes to an end, the star enters the PPN phase.

The PPN is energized by the central star, causing it to emit strong infrared radiation and become a reflection nebula. Collaminated stellar winds from the central star shape and shock the shell into an axially symmetric form, while producing a fast moving molecular wind.[21] The exact point when a PPN becomes a planetary nebula (PN) is defined by the temperature of the central star. The PPN phase continues until the central star reaches a temperature of 30,000 K, after which it is hot enough to ionize the surrounding gas.[22]

Supernova remnants[edit]

The Crab Nebula, an example of a supernova remnant

A supernova occurs when a high-mass star reaches the end of its life. When nuclear fusion in the core of the star stops, the star collapses. The gas falling inward either rebounds or gets so strongly heated that it expands outwards from the core, thus causing the star to explode.[18] The expanding shell of gas forms a supernova remnant, a special diffuse nebula.[18] Although much of the optical and X-ray emission from supernova remnants originates from ionized gas, a great amount of the radio emission is a form of non-thermal emission called synchrotron emission.[18] This emission originates from high-velocity electrons oscillating within magnetic fields.

QMROmega Sagittarii (Omega Sgr, ω Sagittarii, ω Sgr) is a G-type subgiant star in the constellation of Sagittarius.[1] It has an apparent visual magnitude of approximately 4.70.

Name and etymology[edit]

This star, together with :

60 Sgr, 62 Sgr and 59 Sgr, consisting the asterism Terebellum[6] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Terebellum was originally the title for four stars: ω Sgr as Terebellum I, 59 Sgr as Terebellum II, 60 Sgr as Terebellum III and 62 Sgr as Terebellum IV .[7]

ν Sgr, ψ Sgr, τ Sgr, 60 Sgr and ζ Sgr were Al Udḥiyy, the Ostrich's Nest.[6]

In Chinese, 狗國 (Gǒu Guó), meaning Dog Territory, refers to an asterism consisting of ω Sagittarii, 60 Sgr, 62 Sgr and 59 Sgr. Consequently, ω Sagittarii itself is known as 狗國一 (Gǒu Guó yī, English: the First Star of Dog Territory.)[8]

QMRThe Four Symbols (Chinese: 四象; pinyin: Sì Xiàng) are four mythological creatures in the Chinese constellations. They are the Azure Dragon (Chinese: 青龙; pinyin: Qīng Lóng), of the East, the Vermilion Bird (Chinese: 朱雀; pinyin: Zhū Què) of the South, the White Tiger (Chinese: 白虎; pinyin: Baí Hǔ) of the West, and the Black Turtle (Chinese: 玄武; pinyin: Xuán Wū) of the North. Each one of them represents a direction and a season, and each has its own individual characteristics and origins. Symbolically and as part of spiritual and religious belief, they have been culturally important in China, Korea, Vietnam, and Japan. In the latter countries, they are known under the names, correspondingly: Cheongryong (청룡)/Thanh Long/Seiryū (せいりゅう), Jujak (주작)/Chu Tước/Suzaku (すざく), Baek-ho (백호)/Bạch Hổ/Byakko (びゃっこ), and Hyeonmu (현무)/Huyền Vũ/Genbu (げんぶ).

QMR59 Sagittarii (59 Sgr), also known by its Bayer designation b Sagittarii, is a K-type bright giant star in the constellation of Sagittarius.[1] It has an apparent visual magnitude of approximately 4.544.[1] 59 Sagittarii is the southeast corner of the asterism called the Terebellum and, at about 1200 light years from Earth, it is the farthest of the four stars in this asterism.

59 Sagittarii (59 Sgr), also known by its Bayer designation b Sagittarii, is a K-type bright giant star in the constellation of Sagittarius.[1] It has an apparent visual magnitude of approximately 4.544.[1] 59 Sagittarii is the southeast corner of the asterism called the Terebellum and, at about 1200 light years from Earth, it is the farthest of the four stars in this asterism.

62 Sagittarii (62 Sgr) or c Sagittarii (c Sgr) is an M-type giant star in the constellation of Sagittarius.[1] It is the southwest corner of the asterism called the Terebellum. It is an irregular variable whose apparent visual magnitude varies between 4.45 and 4.64,[2] and, at its brightest, it is the brightest of the four stars in the Terebellum. It is approximately 450 light-years from Earth.[1] 62 Sagittarii is the star in the Terebellum which is most distant from its centre; it is 1.72° from its northwest corner, 60 Sagittarii, and 1.37° from its southeast corner, 59 Sagittarii.

QMRAlpha, Beta, Gamma, and Delta Delphini form Job's Coffin

QMRStars[edit]

Delphinus does not have any bright stars; its brightest star is of magnitude 3.8. The main asterism in Delphinus is Job's Coffin, formed from the four brightest stars: Alpha, Beta, Gamma, and Delta Delphini. Alpha and Beta Delphini are named Sualocin and Rotanev, respectively. When read backwards, they read as Nicolaus Venator, the Latinized name of Palermo Observatory's former director, Niccolò Cacciatore. However, Delphinus is in a rich Milky Way star field.[1]

QMRGamma Delphini (γ Del, γ Delphini) is a binary star system approximately 101 light-years away in the constellation of Delphinus. The star marks one corner of the asterism "Job's Coffin". It is one of the best known double stars in the sky, with the primary star beingQMRThe Diamond Cross is an asterism in the southern constellation Carina. The Diamond Cross is composed of four bright stars: Beta, Theta, Upsilon and Omega Carinae. These four bright stars create an almost perfect diamond shape, hence the name "Diamond Cross". The entire asterism is visible to all observers south of 20°N latitude. It bears a striking resemblance to Crux (The Southern Cross) and the False Cross, and, like them, it lacks a central star in its cross pattern, creating a diamond-shaped or kite-like appearance. Both the Diamond Cross and the False Cross are sometimes mistaken for the true cross Crux, although the False Cross has always been a worse deceiver than the Diamond Cross, because most of its stars have approximately the same declinations as the stars of Crux.

QMRBeta Carinae (β Car, β Carinae) is the second brightest star in the constellation Carina and one of the brightest stars in the night sky, with apparent magnitude 1.68.[6] It is the brightest star in the south polar asterism known as the Diamond Cross, marking the southwestern end of the asterism. Beta Carinae also has the traditional name Miaplacidus, meaning "placid waters". It lies near the planetary nebula, IC 2448. Parallax measurements place it at a distance of 113.2 light-years (34.7 parsecs) from Earth.[1]

QMRTheta Carinae (θ Car, θ Carinae) is a star in the southern constellation of Carina. With an apparent visual magnitude of 2.76,[2] it is the brightest star in the open star cluster IC 2602. It marks the northeastern end of the Diamond Cross asterism. Parallax measurements from the Hipparcos mission place this star at a distance of about 460 light-years (140 parsecs) from Earth.

QMR Upsilon Carinae (υ Car, υ Carinae) is a double star in the southern constellation of Carina. It is part of the Diamond Cross asterism in southern Carina. The Upsilon Carinae system has a combined apparent magnitude of +2.97[2] and is approximately 1,400 light years (440 parsecs) from Earth.[1]

QMROmega Carinae (ω Car, ω Carinae) is a star in the constellation Carina. With a declination greater than 70 degrees south of the celestial equator, it is the most southerly of the bright stars of Carina (third-magnitude or brighter), and it is part of a southern asterism known as the Diamond Cross. This star has an apparent visual magnitude of 3.3[2] and is located at a distance of about 342 light-years (105 parsecs) from Earth.[1]

QMRCrux /ˈkrʌks/ is a constellation located in the southern sky in a bright portion of the Milky Way, and is the smallest but one of the most distinctive of the 88 modern constellations. Its name is Latin for cross, and it is dominated by a cross-shaped or kite-like asterism that is commonly known as the Southern Cross.

Predominating the asterism is the most southerly first-magnitude star and brightest star in the constellation, the blue-white Alpha Crucis or Acrux, followed by four other stars, descending in clockwise order by magnitude: Beta, Gamma (one of the closest red giants to Earth), Delta and Epsilon Crucis. Many of these brighter stars are members of the Scorpius–Centaurus Association, a large but loose group of hot blue-white stars that appear to share common origins and motion across the southern Milky Way. Two of the star systems have been found to have planets. The constellation also contains four Cepheid variables that are visible to the naked eye under optimum conditions. Crux also contains the bright and colourful open cluster known Jewel Box (NGC 4755) and, to the southwest, the extensive dark nebula, known as the Coalsack Nebula.

Crux is sometimes confused with the nearby False Cross by stargazers. Crux is somewhat kite-shaped (a Latin cross), and it has a fifth star (ε Crucis). The False Cross is diamond-shaped (a Greek cross), somewhat dimmer on average, does not have a fifth star and lacks the two prominent nearby "Pointer Stars."

Use in navigation[edit]

Locating the south celestial pole

In the Southern Hemisphere, the Southern Cross is frequently used for navigation in much the same way that the Polaris is used in the Northern Hemisphere. Alpha and Gamma (known as Acrux and Gacrux respectively) are commonly used to mark south. Tracing a line from Gacrux to Acrux leads to a point close to the Southern Celestial Pole.[3] Alternatively, if a line is constructed perpendicularly between Alpha Centauri and Beta Centauri, the point where the above-mentioned line and this line intersect marks the Southern Celestial Pole. Another way to find south, strike line through Gacrux and Acrux, 3 1/2 times the distance between Gacrux and Acrux, directly below that point is south. The two stars of Alpha and Beta Centauri are often referred to as the "Southern Pointers" or just "The Pointers", allowing people to easily find the asterism of the Southern Cross or the constellation of Crux. Very few bright stars of importance lie between Crux and the pole itself, although the constellation Musca is fairly easily recognised immediately beneath Crux.[17

A technique used in the field is to clench one's right fist and to view the cross, aligning the first knuckle with the axis of the cross. The tip of the thumb will indicate south.[17]

Argentine Gauchos are well known for using it for night orientation in the vast Pampas and Patagonic regions. It is also of cultural significance, as it is referenced in several songs and literature, including the Martin Fierro. The Argentinian singer Charly Garcia says that he is from the southern cross in the song "No voy en tren".

Within the constellation's borders, there are 49 stars brighter than or equal to apparent magnitude 6.5.[b][14] The four main stars that form the asterism are Alpha, Beta, Gamma, and Delta Crucis. Also known as Acrux, Alpha Crucis is a triple star 321 light-years from Earth. Blue-tinged and magnitude 0.8 to the unaided eye, it has two close components of magnitude 1.3 and 1.8, as well as a wide component of magnitude 5. The two close components are divisible in a small amateur telescope and the wide component is divisible in a pair of binoculars. Beta Crucis, called Mimosa, is a blue-hued giant of magnitude 1.3, 353 light-years from Earth. It is a Beta Cephei-type Cepheid variable with a variation of less than 0.1 magnitudes.[3] Gamma Crucis, called Gacrux, is an optical double star. The primary is a red-hued giant star of magnitude 1.6, 88 light-years from Earth. The secondary is of magnitude 6.5, 264 light-years from Earth. Delta Crucis is a blue-white hued star of magnitude 2.8, 364 light-years from Earth. It is the dimmest of the Southern Cross stars.[3] Like Beta it is a Beta Cepheid.[11]

QMRAlpha Crucis (α Cru, α Crucis, also Acrux, HD 108248) is the brightest star in the constellation Crux, the Southern Cross, and, at a combined visual magnitude 0.77,[7] is the 13th brightest star[7] in the night sky. Acrux is the southernmost first-magnitude star,[7] just a little more southerly than Alpha Centauri.

QMRBeta Crucis, also known as Mimosa or Becrux, is the second brightest star in the constellation Crux (after Alpha Crucis or Acrux) and is the 19th brightest star in the night sky. It forms part of the prominent asterism called the Southern Cross, which appears on five national flags.[4] Although Beta Crucis, "Becrux", is at roughly −60° declination, and therefore not visible north of 30°, in the time of the ancient Greeks and Romans it was visible north of 40° due to the precession of equinoxes, and these civilizations regarded it as part of the constellation Centaurus.[8] Its modern name, Mimosa, which is derived from the Latin word for "actor", may come from the flower of the same name.[9]

QMRParallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.[1][2] The term is derived from the Greek word παράλλαξις (parallaxis), meaning "alteration". Nearby objects have a larger parallax than more distant objects when observed from different positions, so parallax can be used to determine distances.

parallax uses a crossing

QMRChandra uses four pairs of nested mirrors, together with their support structure, called the High Resolution Mirror Assembly (HRMA); the mirror substrate is 2 cm-thick glass, with the reflecting surface a 33 nm iridium coating, and the diameters are 65 cm, 87 cm, 99 cm and 123 cm.[17] The thick substrate and particularly careful polishing allowed a very precise optical surface, which is responsible for Chandra's unmatched resolution: between 80% and 95% of the incoming X-ray energy is focused into a one-arcsecond circle. However, the thickness of the substrates limit the proportion of the aperture which is filled, leading to the low collecting area compared to XMM-Newton.

QMRIn Chinese, 十字架 (Shí Zì Jià), meaning Cross, refers to an asterism consisting of β Crucis, γ Crucis, α Crucis and δ Crucis.[13] Consequently, β Crucis itself is known as 十字架三 (Shí Zì Jià sān, English: the Third Star of Cross.).[14]

Mimosa is represented in the flags of Australia, New Zealand, Samoa and Papua New Guinea as one of five stars making up the Southern Cross. It is also featured in the flag of Brazil, along with 26 other stars, each of which represents a state. Mimosa represents the State of Rio de Janeiro.[15]

QMRTraditional Chinese astronomy has a system of dividing the celestial sphere into asterisms or constellations, known as "officials" (Chinese 星官 xīng guān).[1]

The Chinese asterisms are generally smaller than the constellations of Hellenistic tradition. The Song dynasty (13th-century) Suzhou planisphere shows a total of 283 asterisms, comprising a total of 1,565 individual stars. [2] The asterisms are divided into four groups, the Twenty-Eight Mansions along the ecliptic, and the Three Enclosures of the northern sky. The southern sky was added as a fifth group in the late Ming Dynasty based on European star charts, comprising an additional 23 asterisms.

The Three Enclosures (三垣, Sān Yuán) are centered on the North Celestial Pole and include those stars which could be seen year-round.[3]

The Twenty-Eight Mansions (二十八宿, Èrshíbā Xiù) form an ecliptic coordinate system used for those stars not visible (from China) during the whole year, based on the movement of the moon over a lunar month.[4]

QMRGamma Crucis (γ Cru, γ Crucis), often called Gacrux, is the nearest red giant star to the Sun.[7] The distance to Gacrux has been determined using parallax measurements made during the Hipparcos mission, which yielded a value of 88.6 light-years (27.2 parsecs) away from Earth.[1] With an apparent visual magnitude of +1.63,[10] this is the third-brightest star in the southern circumpolar constellation of Crux, the Southern Cross, and one of the brightest stars in the night sky. Among Portuguese-speaking peoples it is also named "Rubídea" (or Ruby-like), in reference to its color. A line from the two "Pointers", Alpha Centauri through Beta Centauri, leads to within a few degrees of this star.

QMRIn Chinese, 十字架 (Shí Zì Jià), meaning Cross, refers to an asterism consisting of δ Crucis, γ Crucis, α Crucis and β Crucis.[15] Consequently, δ Crucis itself is known as 十字架四 (Shí Zì Jià sì, English: the Fourth Star of Cross.).[16]

The people of Aranda and Luritja tribe around Hermannsburg, Central Australia named Iritjinga, "The Eagle-hawk", a quadrangular arrangement comprising this star, γ Cru (Gacrux), γ Cen (Muhilfain) and δ Cen (Ma Wei).[17]

δ Cru is represented in the flags of Australia, New Zealand and Papua New Guinea as one of the stars comprising the Southern Cross. It is also featured in the flag of Brazil, along with 26 other stars, each of which represents a state. δ Cru represents the State of Minas Gerais.[18]

QMRDelta Crucis (δ Cru, δ Crucis) is a star in the southern circumpolar constellation of Crux. It is sometimes called Pálida (Pale [one]) in Portuguese.[12] This star is of apparent magnitude 2.79 and is located at a distance of about 345 light-years (106 parsecs) from Earth, the faintest of the four bright stars that form the prominent asterism known as the Southern Cross. Delta Crucis is massive, hot and rapidly rotating star that is in the process of evolving into a giant.

QMRMost multiple star systems are triple stars. Systems with four or more components are less likely to occur.[5] Multiple-star systems are called triple, trinary or ternary if they contain three stars; quadruple or quaternary if they contain four stars; quintuple or quintenary with five stars; sextuple or sextenary with six stars; septuple or septenary with seven stars. These systems are smaller than open star clusters, which have more complex dynamics and typically have from 100 to 1,000 stars.[7] Most multiple star systems known are triple; for higher multiplicities, the number of known systems with a given multiplicity decreases exponentially with multiplicity.[8] For example, in the 1999 revision of Tokovinin's catalog[3] of physical multiple stars, 551 out of the 728 systems described are triple. However, because of selection effects, knowledge of these statistics is very incomplete. The fourth square is always different. Star systems are less likely to go to four stars and beyond

QMRThe Kepler 64 system has the planet PH1 (discovered in 2012 by the Planet Hunters group, a part of the Zooniverse) orbiting two of the four stars, making it to be the first known planet to be in a quadruple star system.[50]

QMRKOI-2626 is the first quadruple star system with a planet that is potentially habitable.

QMRQuadruple[edit]

HD 98800 is a quadruple star system located in the TW Hydrae association.

Capella, a pair of giant stars orbited by a pair of red dwarfs, around 42 light years away from the Solar System. It has an apparent magnitude of around −0.47, making Capella one of the brightest stars in the night sky.

4 Centauri[46]

Mizar is often said to have been the first binary star discovered when it was observed in 1650 by Giovanni Battista Riccioli[47], p. 1[48] but it was probably observed earlier, by Benedetto Castelli and Galileo.[citation needed] Later, spectroscopy of its components Mizar A and B revealed that they are both binary stars themselves.[49]

HD 98800

QMRXi Tauri (ξ Tau, ξ Tauri) is a hierarchical quadruple system[4] in the constellation Taurus. It carries the proper name Ushakaron[5][unreliable source?][6][unreliable source?] or Yshakaron, which is Akkadian for "Exacter of Justice and Retribution" or "The Avenger" or "The Vindicator".

Xi Tauri is a spectroscopic and eclipsing quadruple star. It consists of three blue-white B-type main sequence dwarfs. Two of the stars form an eclipsing binary system and revolve around each other once every 7.15 days. These in turn orbit the third star once every 145 days. The fourth star is a F star that orbits the other three stars in a roughly fifty-year period.[7] The mean combined apparent magnitude of the system is +3.73 but, because the stars eclipse one another during their orbits, it is classified as a variable star, and its brightness varies from magnitude +3.70 to +3.79. Xi Tauri is approximately 210 light years from Earth.[1]QMRPH1b (standing for "Planet Hunters 1"), or by its NASA designation Kepler-64b,[6] is an extrasolar planet found in a circumbinary orbit in the quadruple star system Kepler-64. The planet was discovered by two amateur astronomers from the Planet Hunters project of amateur astronomers using data from the Kepler space telescope with assistance of a Yale University team of international astronomers. The discovery was announced on 15 October 2012.[7][8] It is the first known transiting planet in a quadruple star system,[4] first known circumbinary planet in a quadruple star system,[9] and the first planet in a quadruple star system found. It was the first confirmed planet discovered by PlanetHunters.org.[5]

Star system[edit]

The giant planet is Neptune-sized, about 20-55 Earth-masses (M⊕). It has a radius 6.2 times that of Earth's. The star system is 5000 light years from Earth.[2][3][8][10] The planet orbits a close binary, with a more distant binary orbiting at a distance, forming the quadruple star system. The star system has the Kepler Input Catalogue name KIC 4862625 as well as the designation Kepler-64. The close binary (Aa+Ab) that the planet circles has an orbital period of 20 days. They form an eclipsing binary pair.[1] The two stars are (Aa) 1.5 solar mass (M☉) F-type main-sequence star and (Ab) 0.41 M☉ red dwarf.[2][3][4] The planet orbits this binary pair in a 138.3-day orbit. The binary pairs have a separation of 1000 AUs.[1] A photometric-dynamical model was used to model the planetary system of the close binary pair. The distant binary (Ba+Bb) have a pair separation of 60 AU. The two stars are (Ba) 0.99 M☉ G-type main-sequence star and (Bb) 0.51 M☉ red dwarf. The quadruple star system has an estimated age of 2 gigayears.[2] The system is located at right ascension 19h 52m 51.624s declination +39° 57′ 18.36″, so also has a 2MASS catalogue entry of 2MASS 19525162+3957183[11]

QMRMost known extrasolar planet candidates have been discovered using indirect methods and therefore only some of their physical and orbital parameters can be determined. For example, out of the six independent parameters that define an orbit, the radial-velocity method can determine four: semi-major axis, eccentricity, longitude of periastron, and time of periastron. Two parameters remain unknown: inclination and longitude of the ascending node.

QMRHessman et al. state that the implicit system for exoplanet names utterly failed with the discovery of circumbinary planets.[80] They note that the discoverers of the two planets around HW Virginis tried to circumvent the naming problem by calling them "HW Vir 3" and "HW Vir 4", i.e. the latter is the 4th object – stellar or planetary – discovered in the system. They also note that the discoverers of the two planets around NN Serpentis were confronted with multiple suggestions from various official sources and finally chose to use the designations "NN Ser c" and "NN Ser d".

The proposal of Hessman et al. starts with the following two rules:

Rule 1. The formal name of an exoplanet is obtained by appending the appropriate suffixes to the formal name of the host star or stellar system. The upper hierarchy is defined by upper-case letters, followed by lower-case letters, followed by numbers, etc. The naming order within a hierarchical level is for the order of discovery only. (This rule corresponds to the present provisional WMC naming convention.)

Rule 2. Whenever the leading capital letter designation is missing, this is interpreted as being an informal form with an implicit "A" unless otherwise explicitly stated. (This rule corresponds to the present exoplanet community usage for planets around single stars.)

They note that under these two proposed rules all of the present names for 99% of the planets around single stars are preserved as informal forms of the IAU sanctioned provisional standard. They would rename Tau Boötis b formally as Tau Boötis Ab, retaining the prior form as an informal usage (using Rule 2, above).

To deal with the difficulties relating to circumbinary planets, the proposal contains two further rules:

Rule 3. As an alternative to the nomenclature standard in Rule 1, a hierarchical relationship can be expressed by concatenating the names of the higher order system and placing them in parentheses, after which the suffix for a lower order system is added.

Rule 4. When in doubt (i.e. if a different name has not been clearly set in the literature), the hierarchy expressed by the nomenclature should correspond to dynamically distinct (sub)systems in order of their dynamical relevance. The choice of hierarchical levels should be made to emphasize dynamical relationships, if known.

They submit that the new form using parentheses is the best for known circumbinary planets and has the desirable effect of giving these planets identical sublevel hierarchical labels and stellar component names that conform to the usage for binary stars. They say that it requires the complete renaming of only two exoplanetary systems: The planets around HW Virginis would be renamed HW Vir (AB) b & (AB) c, whereas those around NN Serpentis would be renamed NN Ser (AB) b & (AB) c. In addition the previously known single circumbinary planets around PSR B1620-26 and DP Leonis) can almost retain their names (PSR B1620-26 b and DP Leonis b) as unofficial informal forms of the "(AB)b" designation where the "(AB)" is left out.

The discoverers of the circumbinary planet around Kepler-16 followed the naming scheme proposed by Hessman et al. when naming the body Kepler-16 (AB)-b, or simply Kepler-16b when there is no ambiguity.[54]

QMRVela is a constellation in the southern sky. Its name is Latin for the sails of a ship, and it was originally part of a larger constellation, the ship Argo Navis, which was later divided into three parts, the others being Carina and Puppis. With an apparent magnitude of 1.8, its brightest star is the hot blue multiple star Gamma Velorum, one component of which is the brightest Wolf-Rayet star in the sky. Delta and Kappa Velorum, together with Epsilon and Iota Carinae, form the asterism known as the False Cross. 1.95-magnitude Delta is actually a triple or quintuple star system.

QMRThere is another large asterism which, like the Diamond of Virgo, is composed of a pair of equilateral triangles. Sirius (α CMa), Procyon (α CMi), and Betelgeuse (α Ori) form one to the North (Winter Triangle) while Sirius, Naos (ζ Pup), and Phakt (α Col) form another to the South. Unlike the Diamond, however, these triangles meet, not base-to-base, but vertex-to-vertex, forming the Egyptian X. The name derives from both the shape and, because the stars straddle the Celestial Equator, it is more easily seen from south of the Mediterranean than in Europe.

QMRThe Lozenge is a small diamond formed from three stars - Eltanin, Grumium, and Rastaban (Gamma, Xi, and Beta Draconis) - in the head of Draco and one - Iota Herculis - in the foot of Hercules.

QMRFrom latitudes above 40 degrees north especially, a prominent upper-case Y is formed by Arcturus, Gamma and Epsilon Bootis, and Alpha Coronae Borealis (Alphecca or Gemma). Alpha Coronae Borealis is far brighter than either Delta or Beta Bootis, distorting the "kite" or "ice-cream cone" shape of Bootes. From the United Kingdom in particular, where there is serious light pollution in many areas and also twilight all night for much of the time these constellations appear, this "Y" is often visible while β and δ Bootis and the other stars in Corona Borealis are not.

QMRSellers 1909 Quadruplane USA 1909 Experimental Prototype 4 planes. Investigation of low-powered flight.

Pemberton-Billing P.B.29E United Kingdom 1915 Zeppelin killer Prototype 4 planes.[4]

Armstrong Whitworth F.K.9 United Kingdom 1916 Reconnaissance fighter Prototype 4 planes.

Armstrong Whitworth F.K.10 United Kingdom 1917 Reconnaissance fighter Production 4 planes.

Pemberton-Billing P.B.31E United Kingdom 1917 Zeppelin killer Prototype 4 planes. See Supermarine Nighthawk

Supermarine Nighthawk United Kingdom 1917 Zeppelin killer Prototype 4 planes. Renamed Pemberton-Billing P.B.31E.

Wight quadruplane United Kingdom 1917 Fighter Prototype 4 planes.[4]

Euler Vierdecker Germany 1917 Fighter Prototype 4 planes. Standard triplane arrangement of fixed wings with a fourth uppermost wing comprising left and right hand articulated surfaces which acted as full-span ailerons. Two examples were built, with different engines.[4]

Friedrichshafen FF54 Germany 1917 Fighter Prototype 4 planes. Narrow-chord second and third wings, with struts connecting only the upper pair and lower pair of planes. Later modified to triplane configuration.[4]

Naglo D.II Germany 1918 Fighter Prototype 4 planes. Standard triplane arrangement with a smaller fourth wing attached below the main assembly, analogous to a sesquiplane.

Zerbe Air Sedan USA 1919 Experimental Prototype 4 planes. Crashed on first flight.

Besson H-5 France 1922 Transport Prototype 4 planes. Flying boat with two braced biplane wing stacks deeply staggered and vertically offset such that the four wing planes were stacked in an overall zig-zag arrangement.[1]

QMRSupermarine Nighthawk had four planes

From Wikipedia, the free encyclopedia

P.B.31 Nighthawk

Supermarine P.B.31E Nighthawk.jpg

Supermarine Nighthawk

Role Anti-Zeppelin fighter

National origin United Kingdom

Manufacturer Supermarine

First flight 1917

Status Prototype only

Number built 1

Developed from Pemberton Billing P.B.29E

The P.B.31E Nighthawk, the first project of the Pemberton-Billing operation after it became Supermarine Aviation Works Ltd., was a prototype anti-Zeppelin fighter with a crew of three to five and an intended endurance of 9–18 hours. It was first flown in February 1917 with Clifford Prodger at the controls.[1]

Contents [hide]

1 Design and development

2 Operational history

3 Specifications (Prototype)

4 References

Design and development[edit]

The Nighthawk had six-bay swept quadraplane wings and a biplane tailplane with twin fins and rudders. The fuselage filled the gap between the second and third wings; the cockpit, which carried up to the top wing "turret", was enclosed and heated.

Along with the intended long endurance, it was suggested it would be able to patrol at low speeds and await the Zeppelin.[2] For armament, it had a trainable nose-mounted searchlight, a 1½-pounder (37 mm) Davis gun mounted above the top wing with 20 shells, and two .303 in (7.7 mm) Lewis guns. Power for the searchlight was provided by an independent petrol engine-driven generator set made by ABC Motors, possibly the first instance of a recognisable airborne auxiliary power unit.[3]

Operational history[edit]

Although touted as being able to reach 75 mph (121 km/h), the P.B.31E prototype only managed 60 mph (97 km/h) at 6,500 ft (1,981 m) and took an hour to climb to 10,000 ft (3,048 m), which was totally inadequate for intercepting Zeppelins.[4] Given the Anzani engine's reputation for unreliability and overheating, it is unlikely that the aircraft would have delivered the advertised endurance either.

It also had a four member crew and a four blade propeller- resembling a quadrant

QMRThe Armstrong Whitworth F.K.10 was a British two-seat quadruplane (i.e., four wing) fighter aircraft built by Armstrong Whitworth during the First World War. While it was ordered in small numbers for the Royal Flying Corps and Royal Naval Air Service, it was not used operationally. It is one of the few quadruplane aircraft to reach production.

Development[edit]

The F.K.10 was designed in 1916 by Frederick Koolhoven,[1] the chief designer of Armstrong Whitworth Aircraft as a single-engine two-seat fighter. Koolhoven chose the novel quadruplane layout, also used by Pemberton-Billing (later known as Supermarine) for the P.B.29E and Supermarine Nighthawk anti-Zeppelin aircraft, and the contemporary Wight Quadruplane scout. At roughly the same time, Sopwith were building the successful Sopwith Triplane fighter.

The first prototype, the F.K.9 [2] was built and first flown in the summer of 1916, powered by a 110 hp (80 kW) Clerget 9Z engine. It had a shallow fuselage, with the wings joined by plank-like interplane struts,[3] similar to those used by the Sopwith Triplane. After evaluation at the Central Flying School in late 1916, a production order for 50 was placed by the RFC for a modified version, the F.K.10.[2]

The production F.K.10 had a new, deeper fuselage, and a new tail, but retained the wing planform of the F.K.9. The F.K.10 showed inferior performance to the Sopwith 1½ Strutter, which was already in service as a successful two-seat fighter, and only five were built of the RFC order, with a further three built for the RNAS.[2] They were not used operationally and the design was not developed further.[4]

Variants[edit]

F.K.10

F.K.9

Prototype powered by 110 hp (80 kW) Clerget 9Z engine.

F.K.10

Production version with revised fuselage and tail, powered by 130 hp (100 kW) Clerget 9B or Le Rhône 9J engine. 50 ordered, 8 built.

QMRMatthew Bacon Sellers II

From Wikipedia, the free encyclopedia

Matthew Bacon Sellers II

}

Full name Matthew Bacon Sellers II

Born March 29, 1869

Baltimore, Maryland, USA

Died April 5, 1932 (aged 63)

Ardsley-on-Hudson, New York, USA

Cause of death Pulmonary embolism

Spouse Ethel Clark

Aviation career

Known for Inventor of retractable landing gear, Peer of the Wright brothers, Samuel Langley and Octave Chanute. President Wilson appointed him as one of two representatives of the Aeronautical Society of America on the newly formed Naval Consulting Board. Josephus Daniels, the secretary of the navy, recommended for this appointment. Thomas A. Edison chaired this Board composed of prominent scientists of that period.

First flight 1908

Sellers Quadruplane

Famous flights Piloted the first aircraft to take off and land in Kentucky.

Matthew Bacon Sellers II (March 29, 1869 - April 5, 1932) was a United States inventor and scientist known for his work in the field of aviation.

Biography[edit]

He was born on March 29, 1869 in Baltimore, Maryland to Matthew Bacon Sellers I.

In 1915 he joined the Naval Consulting Board.[1]

He died on April 5, 1932 in Ardsley-on-Hudson, New York.[1]

Sellers quadruplane[edit]

Sellers was interested in low-powered flight. He constructed a staggered quadruplane capable of flight on only 5 hp. He flew it at least from 1909 to 1912 and published his researches.[2]

QMRThe Naglo D.II was a German single seat quadruplane fighter, flown late in World War I. It took part in one of the fighter competitions but did not reach production.

Design and development[edit]

The D.II was the only fighter built by Naglo but it was designed by Ing. Gnädig, who at the time was an employee of Albatros Flugzeugwerke and it partly reflected their practice. It was, though, one of the few quadruplanes of World War I. The three upper wings were all similar, having constant chord, squared tips, no sweep and the same span. The lowest of these was attached to the lower fuselage, the middle one to the upper fuselage with a cutout for downward vision. Inboard N-form interplane struts held the upper plane high over the fuselage in place of a cabane. Outboard there was one more N-interplane strut between each wing, four in all. Ailerons were fitted on all three upper wings. The fourth wing, lowest of all, was quite different, much shorter in span. It was mounted independently of the other three, fixed to a dorsal keel extension and braced on each side with a V-strut from about mid-span to the root of the wing above. When the aircraft was parked, the wing was close to the ground and not far behind the undercarriage wheels.[1]

The D.II was powered by a 160 hp (120 kW) Mercedes six-cylinder water-cooled engine, driving a two-blade propeller with a large, domed spinner with was blended into the round, converging contours of the fuselage. The engine's cylinder heads and exhausts were exposed above the fuselage, which overall appears similar to that of the Albatros D.V and may have been based upon it. The D.II had a fixed, single axle conventional undercarriage, the axle fixed to the lower fuselage with a pair of V-struts, and with a tailskid at the rear.[1]

The first flight occurred before 24 May 1918 when the D.II was type tested.[1] It took part in the second D-type contest at Adlershof in mid-1918 and received complimentary comments on its build quality. A need to improve flight characteristics was noted; Naglo was therefore asked to present the D.II for further tests after making modifications.[1

QMRThe Wight Quadruplane, also referred to as the Wight Type 4,[1] was a British single seat quadruplane fighter aircraft built by J Samuel White & Company Limited (Wight Aircraft) during World War I. Testing revealed design deficiencies and after the only example was involved in a crash, further work on the aircraft was abandoned.[1]

Design and development[edit]

The Quadruplane serial no N546 was a prototype designed by Wight Aircraft general manager and design chief Howard T. Wright in 1916. Inspired by the Sopwith Triplane[2] and other multi-wing aircraft of its time, it had an unusual arrangement in which the fuselage was placed between the middle two wings with upper and lower wings attached by struts.[3] Another remarkable feature was that its wingspan was less than the overall length.[2] The wings were cambered on the leading and trailing edges with a flat middle section. This wing design proved to be very inefficient.[2] Power was provided by a 110 hp (82 kW) Clerget 9Z nine-cylinder air cooled rotary engine[4] and it was to be armed with two 0.303 in (7.7 mm) Vickers machine guns.[4]

The original version had two cabane struts of long chord length supporting the upper wing. Four similar type interplane struts were used between the upper three wings, all of which had ailerons.[3] The bottom wing had a shorter span with pairs of struts and cut outs for the landing gear wheels. Because the axle was the same height as the lower wing, the tailskid was very tall to prevent that wings trailing edge from contacting the ground.[2] When tested in mid 1916 the aircraft had difficulty taking off due to shallow wing incidence and displayed dangerous tendencies because of a lack of yaw control and a major redesign was required.[5]

In February 1917 the second version was ready for testing.[3] The single thick struts were replaced with more conventional parallel wire braced struts and the landing gear was lengthened. The new wings were of varying chord and the overall diameter of the fuselage was increased.[3] Most importantly, a larger dorsal fin and rudder were installed. After several disappointing flights at Martlesham Heath the machine was returned to the aircraft production facilities in Cowes for another rework.[3]

The final version had new wings of decreasing span from top to bottom and ailerons only on the upper two wings. At Martlesham Heath in July 1917, flight testing again revealed an unsatisfactory lack of control.[3] In February 1918 the Quadruplane crashed into a cemetery and was written off.[1]

QMRThe Zerbe Air Sedan was an American single engine quadruplane passenger aircraft project started by Professor Jerome S. Zerbe in 1918. The machine made one flight in 1919, was damaged during landing and subsequently abandoned.[1]

Contents [hide]

1 Design and development

2 Operational history

3 References

4 External link

Design and development[edit]

In 1918 Zerbe arrived in Fayetteville to begin work on passenger aircraft for local businessmen. The aircraft, completed in 1919, was a poitive staggered equal span quadruplane with double cambered[2] louvered main wings. Equipped with no tailplane or ailerons, the machine was controlled using "ganged" or linkage connected wings with variable-incidence.[2]

The passenger cabin was made of plywood and fully enclosed with wide stance landing gear attached.[2] A French World War I surplus powerplant was used, and has been reported to be a 90 hp (67 kW) LeRhône or 100 hp (75 kW) Gnôme[2] rotary engine, but evidence suggests it was in fact a Le Rhône 9J of 110 hp (82 kW).[citation needed]

Operational history[edit]

The Air Sedan was piloted by Tom Flannery on its first and only flight in 1919 at the Washington County Fairgrounds in Fayetteville, Arkansas. The aircraft took off and quickly climbed to 100 ft (30 m), flew approximately 1000 ft (300 m) then was significantly damaged during landing.[3] One report states: " After that Zerbe left town never to be heard of or seen again. What happened to the abandoned damaged plane is unknown"

Besson H-5

From Wikipedia, the free encyclopedia

Besson H-5

Besson H-5 aircraft 2.jpg

Besson H-5 circa 1922

Role Transport flying-boat

National origin France

Manufacturer Marcel Besson

First flight 1922

Number built 1

The Besson H-5 (or sometimes Besson MB-11) was a French transport quadruplane flying boat designed by the Marcel Besson company of Boulogne.[1] The only H-5 was damaged and development was abandoned.[1]

Development[edit]

The HB.5 (MB-10) originally started development as an open-sea reconnaissance/bombing flying-boat, but it was completed as a 20-seat passenger transport flying-boat.[1] Described as grotesque it had two sets of staggered biplane wings with an unusual X-type bracing and a biplane tail with triple fins and rudders.[1] Powered by four Salmson 9Z radial engines that were located in tandem pairs in line with the third mainplane.[2] The H-5 had a conventional fuselage on a three-ply mahogany boat hull, which had 24 watertight compartments.[2]

The H-5 was tested from the St Raphael naval air station in 1922 and proved to be stable with little vibration.[1] After a few test flights the H-5 was accidentally damaged and development was abandoned.[1]

QMRA helicopter main rotor or rotor system is the combination of several rotary wings (rotor blades) and a control system that generates the aerodynamic lift force that supports the weight of the helicopter, and the thrust that counteracts aerodynamic drag in forward flight. Each main rotor is mounted on a vertical mast over the top of the helicopter, as opposed to a helicopter tail rotor, which connects through a combination of drive shaft(s) and gearboxes along the tail boom. The blade pitch is typically controlled by a swashplate connected to the helicopter flight controls. Helicopters are one example of rotary-wing aircraft (rotorcraft).

Many rotors are shaped as quadrants. The ancient chinese top was a quadrant rotor (sometimes it was just one line sometimes two orthogonal lines making a quadrant) that could fly

A painting of Madonna and the Christ child features Jesus holding a Chinese top quadrant.

QMR The four stroke internal combustion engine was the engine that made it possible to fly

QMRCierva C.6 replica in Cuatro Vientos Air Museum, Madrid, Spain

This was an auto gyro with roars in the shape of a quadrant

Royal Air Force Avro Rota Mk 1 Cierva Autogiro C30 A, at the Imperial War Museum Duxford,

The Detroit News used an auto gyro with a roar that looked like a quadrant for News stories and using the helicopter for news became popualar

QMRRotorcraft

From Wikipedia, the free encyclopedia

(Redirected from Rotary wing aircraft)

An AS332 helicopter from the Hong Kong Government Flying Service conducts a water bomb demonstration

A rotorcraft or rotary-wing aircraft[1] is a heavier-than-air flying machine that uses lift generated by wings, called rotary wings or rotor blades, that revolve around a mast. Several rotor blades mounted on a single mast are referred to as a rotor. The International Civil Aviation Organization (ICAO) defines a rotorcraft as "supported in flight by the reactions of the air on one or more rotors".[2] Rotorcraft generally include those aircraft where one or more rotors are required to provide lift throughout the entire flight, such as helicopters, cyclocopters, autogyros, and gyrodynes. Compound rotorcraft may also include additional thrust engines or propellers and static lifting surfaces.

Harold Pitcairn revolutionized the Rotable vehicle and he used the quadrant rotary design

Fairey Rotodyne prototype is another example of a rotorcraft with a quadrant rotary

QMRNumber of blades[edit]

A rotary wing is characterised by the number of blades. Typically this is between two and six per driveshaft.

Number of rotors[edit]

A rotorcraft may have one or more rotors. Various rotor configurations have been used:

One rotor. Powered rotors require compensation for the torque reaction causing yaw, except in the case of tipjet drive.

Two rotors. These typically rotate in opposite directions cancelling the torque reaction so that no tail rotor or other yaw stabiliser is needed. These rotors can be laid out as

Tandem - One in front of the other.

Transverse - Side by side.

Coaxial - One rotor disc above the other, with concentric drive shafts.

Intermeshing rotors - Twin rotors at an acute angle from each other, whose nearly-vertical driveshafts are geared together to synchronise their rotor blades so that they intermesh, also called a synchropter.

Three rotors. An uncommon configuration; the 1948 Cierva Air Horse had three rotors as it was not believed a single rotor of sufficient strength could be built for its size. All three rotors turned in the same direction and yaw compensation was provided by inclining each rotor axis to generate rotor thrust components that opposed torque.

Four rotors. Also referred to as quadcopters/quadrotors, they typically have two rotors turning clockwise and two counter-clockwise.

More than four rotors. These designs (referred to generally as multirotors, or sometimes individually as hexacopters[4] and octocopters[5]), have matched sets of rotors turning in opposite directions, and uncommon in full-size manned aircraft, but commonly seen in unmanned aerial vehicle systems.

QMRA quadcopter, also called a quadrotor helicopter or quadrotor,[1] is a multirotor helicopter that is lifted and propelled by four rotors. Quadcopters are classified as rotorcraft, as opposed to fixed-wing aircraft, because their lift is generated by a set of rotors (vertically oriented propellers).

Quadcopters generally use two pairs of identical fixed pitched propellers; two clockwise (CW) and two counter-clockwise (CCW). These use independent variation of the speed of each rotor to achieve control. By changing the speed of each rotor it is possible to specifically generate a desired total thrust; to locate for the centre of thrust both laterally and longitudinally; and to create a desired total torque, or turning force.[2][3]

Quadcopters differ from conventional helicopters which use rotors which are able to vary the pitch of their blades dynamically as they move around the rotor hub. In the early days of flight, quadcopters (then referred to as 'quadrotors') were seen as possible solutions to some of the persistent problems in vertical flight; torque-induced control issues (as well as efficiency issues originating from the tail rotor, which generates no useful lift) can be eliminated by counter-rotation and the relatively short blades are much easier to construct. A number of manned designs appeared in the 1920s and 1930s. These vehicles were among the first successful heavier-than-air vertical take off and landing (VTOL) vehicles.[4] However, early prototypes suffered from poor performance,[4] and latter prototypes required too much pilot work load, due to poor stability augmentation[5] and limited control authority.

In the late 2000s, advances in electronics allowed the production of cheap lightweight flight controllers, accelerometers, global positioning system and cameras. This resulted in a rapid proliferation of small, cheap consumer quadcopters along with other multi rotor designs. Quadcopter designs also became popular in unmanned aerial vehicle (UAV or drone) research. With their small size and maneuverability, these quadcopters can be flown indoors as well as outdoors.[1][6]

At a small size, quadcopters are cheaper and more durable than conventional helicopters due to their mechanical simplicity.[7] Their smaller blades are also advantageous because they possess less kinetic energy, reducing their ability to cause damage. For small-scale quadcopters, this makes the vehicles safer for close interaction. It is also possible to fit quadcopters with guards that enclose the rotors, further reducing the potential for damage.[8] However, as size increases, fixed propeller quadcopters develop disadvantages over conventional helicopters. Increasing blade size increases their momentum. This means that changes in blade speed take longer, which negatively impacts control. At the same time, increasing blade size improves efficiency as it takes less energy to generate thrust by moving a large mass of air at a slow speed than by moving a small mass of air at high speed. Therefore, increasing efficiency comes at the cost of control. Helicopters do not experience this problem as increasing the size of the rotor disk does not significantly impact the ability to control blade pitch.[9]

Due to their ease of construction and control, quadcopter aircraft are frequently used as amateur model aircraft projects.[10][11]

QMRde Bothezat helicopter, 1923 photo was a quadracopter with four rotary wings

Flying prototype of the Parrot AR.Drone

is another example of a quadracopter

Parrot AR.Drone 2.0 take-off, Nevada, 2012

is another example of a quadracopter

The DJI Phantom quadcopter is a commercially produced aircraft with a camera, Wi-Fi connectivity, controller and the pilot’s mobile device

is another example of a quadracopter

QMRQuadcopter coaxial - OnyxStar FOX-C8 XT Observer from AltiGator is another example of a quadracopter

A quadcopter, also called a quadrotor helicopter or quadrotor,[1] is a multirotor helicopter that is lifted and propelled by four rotors. Quadcopters are classified as rotorcraft, as opposed to fixed-wing aircraft, because their lift is generated by a set of rotors (vertically oriented propellers).

Due to their ease of construction and control, quadcopter aircraft are frequently used as amateur model aircraft projects.[10][11]

Early attempts[edit]

Breguet-Richet Gyroplane (1907)

A four-rotor helicopter designed by Louis Breguet. This was the first rotary wing aircraft to lift itself off the ground, although only in tethered flight at an altitude of a few feet. In 1908 it was reported as having flown 'several times', although details are sparse.[12]

Oehmichen No.2 (1920)

Etienne Oehmichen experimented with rotorcraft designs in the 1920s. Among the six designs he tried, his helicopter No.2 had four rotors and eight propellers, all driven by a single engine. The Oehmichen No.2 used a steel-tube frame, with two-bladed rotors at the ends of the four arms. The angle of these blades could be varied by warping. Five of the propellers, spinning in the horizontal plane, stabilized the machine laterally. Another propeller was mounted at the nose for steering. The remaining pair of propellers functioned as its forward propulsion. The aircraft exhibited a considerable degree of stability and increase in control-accuracy for its time, and made over a thousand test flights during the middle 1920s. By 1923 it was able to remain airborne for several minutes at a time, and on April 14, 1924 it established the first-ever FAI distance record for helicopters of 360 m (390 yd). It demonstrated the ability to complete a circular course[13] and later, it completed the first 1 kilometre (0.62 mi) closed-circuit flight by a rotorcraft.

de Bothezat helicopter (1922)

Dr. George de Bothezat and Ivan Jerome developed this aircraft, with six bladed rotors at the end of an X-shaped structure. Two small propellers with variable pitch were used for thrust and yaw control. The vehicle used collective pitch control. Built by the US Air Service, it made its first flight in October 1922. About 100 flights were made by the end of 1923. The highest it ever reached was about 5 m (16 ft 5 in). Although demonstrating feasibility, it was underpowered, unresponsive, mechanically complex and susceptible to reliability problems. Pilot workload was too high during hover to attempt lateral motion.

Convertawings Model A Quadrotor (1956)

This unique helicopter was intended to be the prototype for a line of much larger civil and military quadrotor helicopters. The design featured two engines driving four rotors through a system of v belts. No tailrotor was needed and control was obtained by varying the thrust between rotors.[14] Flown successfully many times in the mid-1950s, this helicopter proved the quadrotor design and it was also the first four-rotor helicopter to demonstrate successful forward flight. Due to a lack of orders for commercial or military versions however, the project was terminated. Convertawings proposed a Model E that would have a maximum weight of 42,000 lb (19 t) with a payload of 10,900 lb (4.9 t) over 300 miles and at up to 173 mph (278 km/h). The Hanson Elastic Articulated (EA) bearingless rotor grew out of work done in the early 1960s at Lockheed California by Thomas F. Hanson, who had previously worked at Convertawings on the quadrotor's rotor design and control system.[15][16]

Curtiss-Wright VZ-7 (1958)

The Curtiss-Wright VZ-7 was a VTOL aircraft designed by the Curtiss-Wright company for the US Army. The VZ-7 was controlled by changing the thrust of each of the four propellers.

Recent developments[edit]

In the last few decades, small-scale unmanned aerial vehicles have been used for many applications. The need for aircraft with greater maneuverability and hovering ability has led to a rise in quadcopter research. The four-rotor design allows quadcopters to be relatively simple in design yet highly reliable and maneuverable. Research is continuing to increase the abilities of quadcopters by making advances in multi-craft communication, environment exploration, and maneuverability. If these developing qualities can be combined, quadcopters would be capable of advanced autonomous missions that are currently not possible with other vehicles.[17]

Some current programs include:

The Bell Boeing Quad TiltRotor concept takes the fixed quadcopter concept further by combining it with the tilt rotor concept for a proposed C-130 sized military transport.

Flying prototype of the Parrot AR.Drone

Parrot AR.Drone 2.0 take-off, Nevada, 2012

The Aermatica Spa Anteos was the first rotary wing RPA (remotely piloted aircraft) to obtain official permission to fly in the civil airspace, by the Italian Civil Aviation Authority (ENAC), and will be the first able to work in non segregated airspace.[18]

AeroQuad and ArduCopter are open-source hardware and software projects based on Arduino for the DIY construction of quadcopters.[19][20]

Parrot AR.Drone is a small radio controlled quadcopter with cameras attached to it built by Parrot SA, designed to be controllable by smartphones or tablet devices.[21][22]

Nixie is a small camera-equipped drone that can be worn as a wrist band.[23][24][25]

In July 2015, a video was posted on YouTube of an airborne quadcopter firing a pistol four times in a wooded area, sparking regulatory concerns.[26][27]

Applications[edit]

Research platform[edit]

Quadcopters are a useful tool for university researchers to test and evaluate new ideas in a number of different fields, including flight control theory, navigation, real time systems, and robotics. In recent years many universities have shown quadcopters performing increasingly complex aerial manoeuvres. Swarms of quadcopters can hover in mid-air,[28][29][30][31] fly in formations,[32][33][34][35][36] and autonomously perform complex flying routines such as flips, darting through hula hoops and organising themselves to fly through windows as a group.[37][38]

There are numerous advantages to using quadcopters as versatile test platforms. They are relatively cheap, available in a variety of sizes and their simple mechanical design means that they can be built and maintained by amateurs. Due to the multi-disciplinary nature of operating a quadcopter, academics from a number of fields need to work together in order to make significant improvements to the way quadcopters perform. Quadcopter projects are typically collaborations between computer science, electrical engineering and mechanical engineering specialists.[37][39

Military and law enforcement[edit]

Quadcopter unmanned aerial vehicles are used for surveillance and reconnaissance by military and law enforcement agencies, as well as search and rescue missions in urban environments.[40] One such example is the Aeryon Scout, created by Canadian company Aeryon Labs,[41] which is a small UAV that can quietly hover in place and use a camera to observe people and objects on the ground. The company claims that the machine played a key role in a drug bust in Central America by providing visual surveillance of a drug trafficker's compound deep in the jungle (Aeryon won't reveal the country's name and other specifics).[42]

After a recreational quadcopter (or "drone") crashed on the White House lawn early in the morning of January 26, 2015,[43] the Secret Service began a series of test flights of such equipment in order to fashion a security protocol against hostile quadcopters.[44]

Commercial use[edit]

The DJI Phantom quadcopter is a commercially produced aircraft with a camera, Wi-Fi connectivity, controller and the pilot’s mobile device

The largest use of quadcopters in the USA has been in the field of aerial imagery. Quadcopter UAVs are suitable for this job because of their autonomous nature and huge cost savings.[17] In the USA, the legality of the use of remotely controlled aircraft for commercial purposes has been a matter of debate. The FAA's stance from 2006 has been that such commercial activity is illegal.[45][46] However, on March 6, 2014, in a court case between Pirker and the FAA, a judge ruled against the FAA's claims, effectively affirming that model aircraft are not covered by the FAA rules.[47]

In December 2014, the FAA released a video detailing many best practices for new drone pilots, including advisories such as keeping their machines below 400 feet and always within visual sight.[48]

In December 2013, the Deutsche Post gathered international media attention with the project Parcelcopter, in which the company tested the shipment of medical products by drone-delivery. Using a Microdrones md4-1000 quadrocopter packages were flown from a pharmacy across the Rhine River. It was the first civilian package-delivery via drones.[49][50]

Very Large Telescope image taken using a quadcopter.[51]

As quadcopters are becoming less expensive media outlets and newspapers are using drones to capture photography of celebrities.[52]

As of March 2015, the United States created an interim policy for the legal use of unmanned aerial vehicles for commercial use where each operator can apply for an exemption filed under Section 333 with the FAA. As of August, 2015 the FAA had granted over 1300 petitions to different use cases and industries.[53]

Flight dynamics[edit]

Each rotor produces both a thrust and torque about its center of rotation, as well as a drag force opposite to the vehicle's direction of flight. If all rotors are spinning at the same angular velocity, with rotors one and three rotating clockwise and rotors two and four counterclockwise, the net aerodynamic torque, and hence the angular acceleration about the yaw axis, is exactly zero, which implies that the yaw stabilizing rotor of conventional helicopters is not needed. Yaw is induced by mismatching the balance in aerodynamic torques (i.e., by offsetting the cumulative thrust commands between the counter-rotating blade pairs).[54]

Quadrotor flight dynamics

Quadrotor yaw torque.png

Schematic of reaction torques on each motor of a quadcopter aircraft, due to spinning rotors. Rotors 1 and 3 spin in one direction, while rotors 2 and 4 spin in the opposite direction, yielding opposing torques for control.

Quadrotorhover.svg

Quadrotoryaw.svg

Quadrotorpitch.svg

A quadrotor hovers or adjusts its altitude by applying equal thrust to all four rotors. A quadrotor adjusts its yaw by applying more thrust to rotors rotating in one direction. A quadrotor adjusts its pitch or roll by applying more thrust to one rotor and less thrust to its diametrically opposite rotor.

Coaxial configuration[edit]

In order to allow more power and stability at reduced weight, a quadcopter, like any other multirotor can employ a coaxial rotor configuration. In this case, each arm has two motors running in opposite directions (one facing up and one facing down).[55]

Quadcopter coaxial - OnyxStar FOX-C8 XT Observer from AltiGator

Vortex ring state[edit]

Small quadcopters are subject to normal rotorcraft aerodynamics, including vortex ring state.[56]

Mechanical structure[edit]

The main mechanical components needed for construction are the frame, propellers (either fixed-pitch or variable-pitch), and the electric motors. For best performance and simplest control algorithms, the motors and propellers should be placed equidistant.[57] Recently, carbon fiber composites have become popular due to their light weight and structural stiffness.[58]

The electrical components needed to construct a working quadcopter are similar to those needed for a modern RC helicopter. They are the electronic speed control module, on-board computer or controller board, and battery. Typically, a hobby transmitter is also used to allow for human input.[59]

Autonomous flight[edit]

Quadcopters and other multicopters often can fly autonomously. Many modern flight controllers use software that allows the user to mark "way-points" on a map, to which the quadcopter will fly and perform tasks, such as landing or gaining altitude.[60] The PX4 autopilot system, an open-source software/hardware combination in development since 2009, has since been adopted by both hobbyists and drone manufacturing companies alike to give their quadcopter projects flight-control capabilities.[61] Other flight applications include crowd control between several quadcopters where visual data from the device is used to predict where the crowd will move next and in turn direct the quadcopter to the next corresponding waypoint.[62]

QMRThe Bell Boeing Quad TiltRotor (QTR) is a proposed four-rotor derivative of the V-22 Osprey tiltrotor developed jointly by Bell Helicopter and Boeing. The concept is a contender in the U.S. Army's Joint Heavy Lift program. It would have a cargo capacity roughly equivalent to the C-130 Hercules, cruise at 250 knots, and land at unimproved sites vertically like a helicopter.[1]

Background[edit]

Bell developed its model D-322 as a quad tiltrotor concept in 1979. The Bell Boeing team disclosed in 1999 a Quad TiltRotor design the companies had been investigating for the previous two years. The design was for a C-130-size V/STOL transport for the US Army's Future Transport Rotorcraft program and would have 50% commonality with the V-22. This design was to have a maximum takeoff weight of 100,000 lb (45,000 kg) with a payload of up to 25,000 lb (11,000 kg) in a hover.[2][3] The design was downsized to be more V-22-based and to have a payload of 18,000 to 20,000 lb (8,200 to 9,100 kg). This version was referred to as "V-44".[2][4] Bell received contracts to study related technologies in 2000. Development was not pursued by the US Department of Defense.[2]

During 2000-06, studies of the aerodynamics and performance of a Quad Tilt Rotor were conducted at the University of Maryland, College Park. This effort was initially funded by NASA/AFDD and subsequently by Bell. An experimental investigation in helicopter mode with ground effect found that it was possible to reduce the download on the aircraft from 10% of the total thrust to an upload of 10% of the thrust.[5] A parallel Computational Fluid Dynamics (CFD) study confirmed these findings.[6]

Joint Heavy Lift studies[edit]

In September 2005 Bell and Boeing received a cost-sharing contract worth US$3.45 million from the U.S. Army's Aviation Applied Technology Directorate for an 18-month conceptual design and analysis study lasting through March 2007, in conjunction with the Joint Heavy Lift program.[7][8] The contract was awarded to Bell Helicopter, which is teaming with Boeing's Phantom Works. The QTR study is one of five designs; another of the five is also a Boeing program, an advanced version of the CH-47 Chinook.[1]

During the initial baseline design study, Bell's engineers are designing the wing, engine and rotor, while the Boeing team is designing the fuselage and internal systems.[9] A similar arrangement is used on the V-22.

A one-fifth-scale wind tunnel model has undergone testing in the Transonic Dynamics Tunnel (a unique transonic wind tunnel) at NASA's Langley Research Center during summer 2006. The "semi-span" model (representing the starboard half of the aircraft) measured 213 inches in length and had powered 91-inch rotors, operational nacelles, and "dynamically representative" wings.[10]

The primary test objective was to study the aeroelastic effects on the aft wing of the forward wing's rotors and establish a baseline aircraft configuration.[1] Alan Ewing, Bell's QTR program manager, reported that "Testing showed those loads from that vortex on the rear rotor [are the] same as the loads we see on the front [rotors]," and "Aeroelastic stability of the wing looks exactly the same as the conventional tiltrotor". These tests used a model with a three-bladed rotor, future tests will explore the effects of using a four-bladed system.[9]

Besides the research performed jointly under the contract, Bell has funded additional research and wind tunnel testing in cooperation with NASA and the Army.[11] After submission of initial concept study reports, testing of full-scale components and possibly a sub-scale vehicle test program was expected to begin.[1] Pending approval, first flight of a full-scale prototype aircraft was slated for 2012.[9]

The study was completed in May 2007,[12] with the Quad TiltRotor selected for further development. However, additional armor on Future Combat Systems manned ground vehicles caused their weight to increase from 20 tons to 27 tons, requiring a larger aircraft.[13] In mid-2008, the U.S. Army continued the Joint Heavy Lift (JHL) studies with new contracts to the Bell-Boeing and Karem Aircraft/Lockheed Martin teams. The teams were to modify their designs to reach new JHL specifications. JHL became part of the new US Air Force/Army Joint Future Theater Lift (JFTL) program in 2008.[14] In mid-2010, the US DoD was formulating a vertical lift aircraft plan with JFTL as a part.[15] The DoD also requested information from the aerospace industry on technologies for JFTL in October 2010.[16][17]

Design[edit]

Quad TiltRotor schematic

The conceptual design is for a large tandem wing aircraft with V-22 type engines and 50-foot rotors at each of the four wing tips. The C-130-size fuselage would have a 747-inch-long cargo bay with a rear loading ramp that could carry 110 paratroopers or 150 standard-seating passengers. In cargo configuration, it would accommodate eight 463L pallets.[9]

In addition to the baseline configuration, the Bell-Boeing team is including eight possible variants, or "excursion designs", including a sea-based variant. The design team is planning on payloads ranging from 16 to 26 tons and a range of 420 to 1000 nmi. The baseline version includes a fully retractable refueling probe and an interconnecting drive system for power redundancy.[9]

One of the design excursions explored by the team, dubbed the "Big Boy", would have 55-foot rotors and an 815-inch-long cargo bay, making it able to carry one additional 463L pallet and accommodate a Stryker armored combat vehicle.[9]

QMRThe Bell X-22 was an American V/STOL X-plane with four tilting ducted fans. Takeoff was to selectively occur either with the propellers tilted vertically upwards, or on a short runway with the nacelles tilted forward at approximately 45°. Additionally, the X-22 was to provide more insight into the tactical application of vertical takeoff troop transporters such as the preceding Hiller X-18 and the X-22 successor, the Bell XV-15. Another program requirement was a true airspeed in level flight of at least 525 km/h (326 mph; 283 knots).

QMRThe V-22 is equipped with a glass cockpit, which incorporates four Multi-function displays (MFDs, compatible with night-vision goggles)[

QMRThe Hiller X-18 was an experimental cargo transport aircraft designed to be the first testbed for tiltwing and VSTOL (vertical/short takeoff and landing) technology.

It has four rotars

QMRThe X-planes are a series of experimental United States airplanes and helicopters (and some rockets) used to test and evaluate new technologies and aerodynamic concepts. Most of the X-planes have been operated by the National Advisory Committee for Aeronautics (NACA) or, later, the National Aeronautics and Space Administration (NASA), often in conjunction with the United States Air Force. The majority of X-plane testing has occurred at Edwards Air Force Base.[1]

Planes themselves are shaped like quadrants

QMRLockheed Martin states that the weapons load can be configured as all-air-to-ground or all-air-to-air, and has suggested that a Block 5 version will carry three weapons per bay instead of two, replacing the heavy bomb with two smaller weapons such as AIM-120 AMRAAM air-to-air missiles.[278] Upgrades are to allow each weapons bay to carry four GBU-39 Small Diameter Bombs (SDB) for A and C models, or three in F-35B.[279] Another option is four GBU-53/B Small Diameter Bomb IIs in each bay on all F-35 variants.[280] The F-35A has been outfitted with four SDB II bombs and an AMRAAM missile to test adequate bay door clearance,[281] as well as the C-model, but the VTOL F-35B will not be able to carry the required load of four SDB IIs in each weapons bay upon reaching IOC due to weight and dimension constraints; F-35B bay changes are to be incorporated to increase SDB II loadout around 2022 in line with the Block 4 weapons suite.[282] The Meteor (missile) air-to-air missile may be adapted for the F-35, a modified Meteor with smaller tailfins for the F-35 was revealed in September 2010; plans call for the carriage of four Meteors internally.[283] The United Kingdom planned to use up to four AIM-132 ASRAAM missiles internally, later plans call for the carriage of two internal and two external ASRAAMs.[284] The external ASRAAMs are planned to be carried on "stealthy" pylons; the missile allows attacks to slightly beyond visual range without employing radar

QMRBoys flying a kite in 1828 Germany, by Johann Michael Voltz

The paradigmatic kites are shaped like quadrants.

QMRIn aviation, a multiplane is a fixed-wing aircraft-configuration featuring multiple wing planes. The wing planes may be stacked one above another, or one behind another, or both in combination. Types having a small number of planes have specific names and are not usually described as multiplanes:

Biplane - two wings stacked one above the other

Triplane - three wings stacked one above another

Quadruplane- four stacked wings

Tandem wing - two main planes, one behind the other. The tandem triple or tandem triplet configuration has three lifting surfaces one behind another.

While triplane, quadruplane and tandem designs are relatively uncommon, aircraft with more than four sets of wings rarely occur - none have proven successful.

QMRQuadruplanes[edit]

Quadruplane.svg

The quadruplane configuration takes the triplane approach a step further, using efficient wings of high aspect ratio and stacking them to allow a compact and light weight design. During the pioneer years of aviation and World War I, a few designers sought these potential benefits for a variety of reasons, mostly with little success.

From ca. 1909 the American inventor Matthew Bacon Sellers II made a series of flights in the Sellers 1909 Quadruplane, progressively fitted with powerplants of decreasing power, in order to investigate low-powered flight. He eventually achieved flight on only 5 to 6 hp at a speed of 20 mph.

Pemberton-Billing Ltd. made two prototype Zeppelin killers, the Pemberton-Billing P.B.29E and Pemberton-Billing P.B.31E, respectively in 1915 and 1917. They were comparatively large, twin-engined fighters. After the company changed its name to Supermarine, the P.B.31E became known as the Supermarine Nighthawk.

Following test flights with the prototype Armstrong Whitworth F.K.9 in 1916, a small number of Armstrong Whitworth F.K.10 quadruplane reconnaissance fighters were produced, but none saw combat action.

The private-venture Wight quadruplane scout fighter was flown in 1917.

The Euler Vierdecker of 1917 unusually featured a standard triplane arrangement of fixed wings with a fourth uppermost wing comprising left and right hand articulated surfaces which acted as full-span ailerons. Two examples were built, with different engines.

Also in 1917, Friedrichshafen created the even more unusual Friedrichshafen FF54 scout fighter, which featured narrow-chord second and third wings, with struts connecting only the upper pair and lower pair of planes. The prototype proved unacceptable in the air and was later modified as an equally unsuccessful triplane, again with a short-chord intermediate plane.

The Naglo D.II quadruplane fighter of 1918 featured a standard triplane arrangement with a smaller fourth wing attached below the main assembly, somewhat analogous to a sesquiplane. It participated in Germany's second D-type contest in 1918, and was praised for its construction and workmanship.

In 1922 Besson constructed the H-5, a prototype quadruplane flying boat transport. It was unusual in having two braced biplane wing stacks deeply staggered and vertically offset such that the four wing planes were stacked in an overall zig-zag arrangement.[1] The only example was damaged and development was abandoned.

More than four planes[edit]

Multiplane.svg

Any fixed-wing aircraft with more than four wing planes may be referred to as a multiplane. Planes may be stacked vertically as with a biplane, or placed one in front of another as with a tandem wing. Both principles may be combined.

QMRPhillips Multiplane II United Kingdom 1907 Experimental Prototype 200 planes in 4 tandem stacks of 50 planes each. First successful powered flight in Great Britain.

Williams 1908 Multiplane USA 1908 Experimental Prototype 4 planes, in tandem.[2]

AEA Cygnet II USA 1908 Experimental Prototype 16 planes of repeat tetrahedral form, stacked. Cellular multiplane designed by Alexander Graham Bell. Failed to fly.

QMRThe Cygnet (or Aerodrome #5) was an extremely unorthodox early Canadian aircraft, with a wall-like "wing" made up of 3,393 tetrahedral cells.[1] It was a powered version of the Cygnet tetrahedral kite designed by Dr Alexander Graham Bell in 1907 and built by the newly founded Aerial Experiment Association.

Design and development[edit]

Bell's experiments with tetrahedral kites had explored the advantages of utilizing great banks of cells to create a lifting body leading to the Cygnet I. On 6 December 1907, Thomas Selfridge piloted the kite as it was towed into the air behind a motorboat, eventually reaching a height of 168 ft (51 m). This was the first recorded heavier-than-air flight in Canada.[2] While demonstrably able to fly as a person-carrying kite, it seemed unpromising as a direction for research into powered flight. It was difficult to control, and was in fact destroyed when it hit the water at the end of the flight.

The following year, a smaller copy of the design was built as the Cygnet II, now equipped with wheeled undercarriage and a Curtiss V-8 engine.[3]

Operational history[edit]

Attempts to fly the Cygnet II at Baddeck, Nova Scotia between 22 and 24 February 1909, met with failure. When the AEA Silver Dart was ready for flight testing, the engine was removed from the Cygnet II, and then returned. Rebuilt again as the Cygnet III with a more powerful 70 hp Gnome Gamma engine, its final flight was on 19 March 1912, at Bras d'Or Lake, Nova Scotia, piloted by John McCurdy.[4] The results were highly unsatisfactory with the Cygnet III only able to lift off the ground for a foot or two, typically considered remaining in ground effect. After a final trial on 17 March, the tetrahedral cell bank failed structurally, leaving the aircraft irreparably damaged. The Cygnet II and III were abandoned following this flight attempt.[5]

QMRLawrence Hargrave invented his box kite in 1885, and on 12 November 1894, lifted himself from the beach in Stanwell Park, New South Wales using a four box kite rig, attached to the ground by piano wire. Using this rig he lifted himself 16 feet (4.9 m) above the ground, despite the combined weight of his body and the rig weighing 208 lb (94.5 kg)

QMRAlexander Graham Bell developed a tetrahedral kite, constructed of sticks arranged in a honeycomb of triangular sections, called cells. From a one cell model at the beginning of the 1890s, Bell advanced to a 3,393 cell "Cygnet" model in the early 1900s. This 40 foot (12.2 m) long, 200 lb (91 kg) kite was towed by a steamer in Baddeck Bay, Nova Scotia on December 6, 1907 and carried a man 168 feet (51.2 m) above the sea. Roald Amundsen, the polar explorer, commissioned tests on a man-lifting kite to see whether it would be suitable for use for observation in the Arctic, but the trials were unsatisfactory, and the idea was never developed.

tetra means fourQMRA tetrahedral kite is a multicelled rigid box kite composed of tetrahedrally shaped cells to create a kind of tetrahedral truss. The cells are usually arranged in such a way that the entire kite is also a regular tetrahedron. The kite can be described as a compound dihedral kite as well.

An early design of the tetrahedron kite from Alexander Graham Bell

A Tetrahedral kite being flown

This kite was invented by Alexander Graham Bell. It came about from his experiments with Hargrave's Box Kites and his attempts to build a kite that was scalable and big enough to carry both a man and a motor. As such, it was an early experiment on the road to manned flight. He worked on the kites between 1895 and 1910.[1] Bell wrote about his discovery of this concept in the June 1903 issue of National Geographic magazine; the article was titled "Tetrahedral Principle in Kite Structure".[2]

From an initial one cell model, Bell advanced to a 3,393 cell "Cygnet" model in 1907. This 40-foot (12.2 m) long, 200 pound (91 kilogram) kite was towed by a steamer offshore near Baddeck, Nova Scotia on 6 December 1907 and carried a man 168 feet (51.2 metres) above the water.

Bell also experimented with a large circular "tetrahedral truss" design during the same period.[3]

The tetrahedral kite, while not easy to make compared to the simple cross kite, is very stable and easy to fly. It flies well in moderate to heavy winds if it is properly set up.

QMRA box kite is a high performance kite, noted for developing relatively high lift; it is a type within the family of cellular kites. The typical design has four parallel struts. The box is made rigid with diagonal crossed struts. There are two sails, or ribbons, whose width is about a quarter of the length of the box. The ribbons wrap around the ends of the box, leaving the ends and middle of the kite open. In flight, one strut is the bottom, and the bridle is tied between the top and bottom of this strut. The dihedrals of the sails help stability.

QMRSpace frames were independently developed by Alexander Graham Bell around 1900 and Buckminster Fuller in the 1950s. Bell's interest was primarily in using them to make rigid frames for nautical and aeronautical engineering, with the tetrahedral truss being one of his inventions. However few of his designs were realised. Buckminster Fuller's focus was architectural structures; his work had greater influence. Introduction of the first space grid system called MERO in 1943 in Germany initiated the use of space trusses in architecture. The commonly used method, still in use has individual tubular members connected at node joints (ball shaped). Different systems like space deck system, octet truss system, Pyramitec system, Unibat system, Cubic system, etc. were developed. A method of Tree supports was developed to replace the individual columns.[1]

Overview[edit]

Simplified space frame roof with the half-octahedron highlighted in blue

The simplest form of space frame is a horizontal slab of interlocking square pyramids and tetrahedra built from aluminium or tubular steel struts. In many ways this looks like the horizontal jib of a tower crane repeated many times to make it wider. A stronger form is composed of interlocking tetrahedra in which all the struts have unit length. More technically this is referred to as an isotropic vector matrix or in a single unit width an octet truss. More complex variations change the lengths of the struts to curve the overall structure or may incorporate other geometrical shapes.

Barrel vaults. This type of vault has a cross section of a simple arch. Usually this type of space frame does not need to use tetrahedral modules or pyramids as a part of its backing.

Spherical domes and other compound curves usually require the use of tetrahedral modules or pyramids and additional support from a skin.

QMRThe tetrahedral-octahedral honeycomb, alternated cubic honeycomb is a space-filling tessellation (or honeycomb) in Euclidean 3-space. It is composed of alternating octahedra and tetrahedra in a ratio of 1:2.

Other names include half cubic honeycomb, half cubic cellulation, or tetragonal disphenoidal cellulation. John Horton Conway calls this honeycomb a tetroctahedrille, and its dual dodecahedrille.

It is vertex-transitive with 8 tetrahedra and 6 octahedra around each vertex. It is edge-transitive with 2 tetrahedra and 2 octahedra alternating on each edge.

A geometric honeycomb is a space-filling of polyhedral or higher-dimensional cells, so that there are no gaps. It is an example of the more general mathematical tiling or tessellation in any number of dimensions.

Honeycombs are usually constructed in ordinary Euclidean ("flat") space, like the convex uniform honeycombs. They may also be constructed in non-Euclidean spaces, such as hyperbolic uniform honeycombs. Any finite uniform polytope can be projected to its circumsphere to form a uniform honeycomb in spherical space.

It is part of an infinite family of uniform honeycombs called alternated hypercubic honeycombs, formed as an alternation of a hypercubic honeycomb and being composed of demihypercube and cross-polytope facets. It is also part of another infinite family of uniform honeycombs called simplectic honeycombs.

In this case of 3-space, the cubic honeycomb is alternated, reducing the cubic cells to tetrahedra, and the deleted vertices create octahedral voids. As such it can be represented by an extended Schläfli symbol h{4,3,4} as containing half the vertices of the {4,3,4} cubic honeycomb.

There's a similar honeycomb called gyrated tetrahedral-octahedral honeycomb which has layers rotated 60 degrees so half the edges have neighboring rather than alternating tetrahedra and octahedra.

Alternated cubic honeycomb slices[edit]

The alternated cubic honeycomb can be sliced into sections, where new square faces are created from inside of the octahedron. Each slice will contain up and downward facing square pyramids and tetrahedra sitting on their edges. A second slice direction needs no new faces and includes alternating tetrahedral and octahedral. This slab honeycomb is a scaliform honeycomb rather than uniform because it has nonuniform cells.

Its vertex arrangement represents an A3 lattice or D3 lattice.[2][3] It is the 3-dimensional case of a simplectic honeycomb. Its Voronoi cell is a rhombic dodecahedron, the dual of the cuboctahedron vertex figure for the tet-oct honeycomb.

The D+

3 packing can be constructed by the union of two D3 (or A3) lattices. The D+

n packing is only a lattice for even dimensions. The kissing number is 22=4, (2n-1 for n<8, 240 for n=8, and 2n(n-1) for n>8).[4]

CDel node 1.pngCDel split1.pngCDel nodes.pngCDel split2.pngCDel node.png ∪ CDel node.pngCDel split1.pngCDel nodes.pngCDel split2.pngCDel node 1.png

The A*

3 or D*

3 lattice (also called A4

3 or D4

3) can be constructed by the union of all four A3 lattices, and is identical to the vertex arrangement of the disphenoid tetrahedral honeycomb, dual honeycomb of the uniform bitruncated cubic honeycomb:[5] It is also the body centered cubic, the union of two cubic honeycombs in dual positions.

CDel node 1.pngCDel split1.pngCDel nodes.pngCDel split2.pngCDel node.png ∪ CDel node.pngCDel split1.pngCDel nodes 10luru.pngCDel split2.pngCDel node.png ∪ CDel node.pngCDel split1.pngCDel nodes 01lr.pngCDel split2.pngCDel node.png ∪ CDel node.pngCDel split1.pngCDel nodes.pngCDel split2.pngCDel node 1.png = dual of CDel node 1.pngCDel split1.pngCDel nodes 11.pngCDel split2.pngCDel node 1.png = CDel node 1.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node.png ∪ CDel node.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node 1.png.

The kissing number of the D*

3 lattice is 8[6] and its Voronoi tessellation is a bitruncated cubic honeycomb, CDel branch 11.pngCDel 4a4b.pngCDel nodes.png, containing all truncated octahedral Voronoi cells, CDel node.pngCDel 4.pngCDel node 1.pngCDel 3.pngCDel node 1.png.[7]

QMRCantic cubic honeycomb[edit]

Cantic cubic honeycomb

Type Uniform honeycomb

Schläfli symbol h2{4,3,4}

Coxeter diagrams CDel nodes 10ru.pngCDel split2.pngCDel node 1.pngCDel 4.pngCDel node.png = CDel node h1.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node 1.pngCDel 4.pngCDel node.png

CDel node 1.pngCDel split1.pngCDel nodes 11.pngCDel split2.pngCDel node.png = CDel node h1.pngCDel 4.pngCDel node.pngCDel split1.pngCDel nodes 11.png

Cells t{3,4} Uniform polyhedron-43-t12.png

r{4,3} Uniform polyhedron-43-t1.png

t{3,3} Uniform polyhedron-33-t01.png

Vertex figure Truncated alternated cubic honeycomb verf.png

Coxeter groups [4,31,1], {\tilde{B}}_3

[3[4]], {\tilde{A}}_3

Symmetry group Fm3m (225)

Dual half oblate octahedrille

Properties vertex-transitive

The cantic cubic honeycomb, cantic cubic cellulation or truncated half cubic honeycomb is a uniform space-filling tessellation (or honeycomb) in Euclidean 3-space. It is composed of truncated octahedra, cuboctahedra and truncated tetrahedra in a ratio of 1:1:2. Its vertex figure is a rectangular pyramid.

John Horton Conway calls this honeycomb a truncated tetraoctahedrille, and its dual half oblate octahedrille.

Truncated alternated cubic tiling.png HC A1-A3-A4.png

Symmetry[edit]

It has two different uniform constructions. The {\tilde{A}}_3 construction can be seen with alternately colored truncated tetrahedra.

QMRThe runcic cubic honeycomb or runcicantic cubic cellulation is a uniform space-filling tessellation (or honeycomb) in Euclidean 3-space. It is composed of rhombicuboctahedra, cubes, and tetrahedra in a ratio of 1:1:2. Its vertex figure is a triangular prism, with a tetrahedron on one end, cube on the opposite end, and three rhombicuboctahedra around the trapezoidal sides.

John Horton Conway calls this honeycomb a 3-RCO-trille, and its dual quarter cubille.

Runcinated alternated cubic tiling.pngHC A5-P2-P1.png

Related honeycombs[edit]

It is related to the runcinated cubic honycomb, with quarter of the cubes alternated into tetrahedra, and half expanded into rhombicuboctahedra.

Runcinated cubic honeycomb.png

Runcinated cubic

CDel node 1.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node 1.png Runcinated alternated cubic honeycomb.jpg

Runcic cubic

CDel node h1.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node 1.png = CDel nodes 10ru.pngCDel split2.pngCDel node.pngCDel 4.pngCDel node 1.png

{4,3}, {4,3}, {4,3}, {4,3}

CDel node 1.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node.png, CDel node 1.pngCDel 4.pngCDel node.pngCDel 2.pngCDel node 1.png, CDel node 1.pngCDel 2.pngCDel node.pngCDel 4.pngCDel node 1.png, CDel node.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node 1.png h{4,3}, rr{4,3}, {4,3}

CDel node h1.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node.png, CDel node 1.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node 1.png, CDel node.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node 1.png

This honeycomb can be divided on truncated square tiling planes, using the octagons centers of the rhombicuboctahedra, creating square cupolae. This scaliform honeycomb is represented by Coxeter diagram CDel node h.pngCDel 2x.pngCDel node h.pngCDel 4.pngCDel node.pngCDel 4.pngCDel node 1.png, and symbol s3{2,4,4}, with coxeter notation symmetry [2+,4,4].

Gyrated tetrahedral-octahedral honeycomb[edit]

Gyrated tetrahedral-octahedral honeycomb

Type convex uniform honeycomb

Coxeter diagram CDel node.pngCDel 3.pngCDel node.pngCDel 6.pngCDel node h.pngCDel 2x.pngCDel node h.pngCDel infin.pngCDel node.png

CDel node.pngCDel 6.pngCDel node h.pngCDel 3.pngCDel node h.pngCDel 2x.pngCDel node h.pngCDel infin.pngCDel node.png

CDel branch hh.pngCDel split2.pngCDel node h.pngCDel 2x.pngCDel node h.pngCDel infin.pngCDel node.png

Schläfli symbol h{4,3,4}:g

h{6,3}h{∞}

s{3,6}h{∞}

s{3[3]}h{∞}

Cell types {3,3}, {3,4}

Vertex figure Gyrated alternated cubic honeycomb verf.png

Triangular orthobicupola G3.4.3.4

Space group P63/mmc (194)

[3,6,2+,∞]

Dual trapezo-rhombic dodecahedral honeycomb

Properties vertex-transitive, face-transitive

The gyrated tetrahedral-octahedral honeycomb or gyrated alternated cubic honeycomb is a space-filling tessellation (or honeycomb) in Euclidean 3-space made up of octahedra and tetrahedra in a ratio of 1:2.

It is vertex-uniform with 8 tetrahedra and 6 octahedra around each vertex.

It is not edge-uniform. All edges have 2 tetrahedra and 2 octahedra, but some are alternating, and some are paired.

Gyrated alternated cubic.pngGyrated alternated cubic honeycomb.png

It can be seen as reflective layers of this layer honeycomb:

CDel node h.pngCDel 2x.pngCDel node h.pngCDel 6.pngCDel node.pngCDel 3.pngCDel node.png

Tetroctahedric semicheck.png

Construction by gyration[edit]

This is a less symmetric version of another honeycomb, tetrahedral-octahedral honeycomb, in which each edge is surrounded by alternating tetrahedra and octahedra. Both can be considered as consisting of layers one cell thick, within which the two kinds of cell strictly alternate. Because the faces on the planes separating these layers form a regular pattern of triangles, adjacent layers can be placed so that each octahedron in one layer meets a tetrahedron in the next layer, or so that each cell meets a cell of its own kind (the layer boundary thus becomes a reflection plane). The latter form is called gyrated.

The vertex figure is called a triangular orthobicupola, compared to the tetrahedral-octahedral honeycomb whose vertex figure cuboctahedron in a lower symmetry is called a triangular gyrobicupola, so the gyro- prefix is reversed in usage.

Construction by alternation[edit]

Vertex figure with nonplanar 3.3.3.3 vertex configuration for the triangular bipyramids

The geometry can also be constructed with an alternation operation applied to a hexagonal prismatic honeycomb. The hexagonal prism cells become octahedra and the voids create triangular bipyramids which can be divided into pairs of tetrahedra of this honeycomb. This honeycomb with bipyramids is called a ditetrahedral-octahedral honeycomb. There are 3 Coxeter-Dynkin diagrams, which can be seen as 1, 2, or 3 colors of octahedra:

CDel node.pngCDel 3.pngCDel node.pngCDel 6.pngCDel node h.pngCDel 2x.pngCDel node h.pngCDel infin.pngCDel node.png

CDel node.pngCDel 6.pngCDel node h.pngCDel 3.pngCDel node h.pngCDel 2x.pngCDel node h.pngCDel infin.pngCDel node.png

CDel branch hh.pngCDel split2.pngCDel node h.pngCDel 2x.pngCDel node h.pngCDel infin.pngCDel node.png

Gyroelongated alternated cubic honeycomb[edit]

Gyroelongated alternated cubic honeycomb

Type Uniform honeycomb

Schläfli symbol h{4,3,4}:ge

{3,6}h1{∞}

Coxeter diagram CDel node.pngCDel 3.pngCDel node.pngCDel 6.pngCDel node h.pngCDel 2x.pngCDel node h.pngCDel infin.pngCDel node 1.png

CDel node.pngCDel 6.pngCDel node h.pngCDel 3.pngCDel node h.pngCDel 2x.pngCDel node h.pngCDel infin.pngCDel node 1.png

CDel branch hh.pngCDel split2.pngCDel node h.pngCDel 2x.pngCDel node h.pngCDel infin.pngCDel node 1.png

Cell types {3,3}, {3,4}, (3.4.4)

Face types {3}, {4}

Vertex figure Gyroelongated alternated cubic honeycomb verf.png

Space group P63/mmc (194)

[3,6,2+,∞]

Properties vertex-uniform

The gyroelongated alternated cubic honeycomb or elongated triangular antiprismatic cellulation is a space-filling tessellation (or honeycomb) in Euclidean 3-space. It is composed of octahedra, triangular prisms, and tetrahedra in a ratio of 1:2:2.

It is vertex-uniform with 3 octahedra, 4 tetrahedra, 6 triangular prisms around each vertex.

It is one of 28 convex uniform honeycombs.

The elongated alternated cubic honeycomb has the same arrangement of cells at each vertex, but the overall arrangement differs. In the elongated form, each prism meets a tetrahedron at one of its triangular faces and an octahedron at the other; in the gyroelongated form, the prism meets the same kind of deltahedron at each end.

Gyroelongated alternated cubic tiling.png Gyroelongated alternated cubic honeycomb.png

Elongated alternated cubic honeycomb[edit]

Elongated alternated cubic honeycomb

Type Uniform honeycomb

Schläfli symbol h{4,3,4}:e

{3,6}g1{∞}

Cell types {3,3}, {3,4}, (3.4.4)

Vertex figure Gyrated triangular prismatic honeycomb verf.png

triangular cupola joined to isosceles hexagonal pyramid

Space group ?

Properties vertex-transitive

The elongated alternated cubic honeycomb or elongated triangular gyroprismatic cellulation is a space-filling tessellation (or honeycomb) in Euclidean 3-space. It is composed of octahedra, triangular prisms, and tetrahedra in a ratio of 1:2:2.

It is vertex-uniform with 3 octahedra, 4 tetrahedra, 6 triangular prisms around each vertex. Each prism meets an octahedron at one end and a tetrahedron at the other.

It is one of 28 convex uniform honeycombs.

It has a gyrated form called the gyroelongated alternated cubic honeycomb with the same arrangement of cells at each vertex.

QMRHeavier than air[edit]

Main article: Early flying machines

The 17th and 18th centuries[edit]

Italian inventor, Tito Livio Burattini, invited by the Polish King Władysław IV to his court in Warsaw, built a model aircraft with four fixed glider wings in 1647.[24] Described as "four pairs of wings attached to an elaborate 'dragon'", it was said to have successfully lifted a cat in 1648 but not Burattini himself.[25] He promised that "only the most minor injuries" would result from landing the craft.[26] His "Dragon Volant" is considered "the most elaborate and sophisticated aeroplane to be built before the 19th Century".[27]

QMRIn 1809, goaded by the farcical antics of his contemporaries (see above), he began the publication of a landmark three-part treatise titled "On Aerial Navigation" (1809–1810).[32] In it he wrote the first scientific statement of the problem, "The whole problem is confined within these limits, viz. to make a surface support a given weight by the application of power to the resistance of air." He identified the four vector forces that influence an aircraft: thrust, lift, drag and weight and distinguished stability and control in his designs.

QMRThe invention of the box kite during this period by the Australian Lawrence Hargrave would lead to the development of the practical biplane. In 1894 Hargrave linked four of his kites together, added a sling seat, and flew 16 feet (4.9 m). Later pioneers of manned kite flying included Samuel Franklin Cody in England and Captain Génie Saconney in France.

QMRThe first flight by Orville Wright, of 120 feet (37 m) in 12 seconds, was recorded in a famous photograph. In the fourth flight of the same day, Wilbur Wright flew 852 feet (260 m) in 59 seconds. The flights were witnessed by three coastal lifesaving crewmen, a local businessman, and a boy from the village, making these the first public flights and the first well-documented ones.[57]

Orville described the final flight of the day: "The first few hundred feet were up and down, as before, but by the time three hundred feet had been covered, the machine was under much better control. The course for the next four or five hundred feet had but little undulation. However, when out about eight hundred feet the machine began pitching again, and, in one of its darts downward, struck the ground. The distance over the ground was measured to be 852 feet (260 m); the time of the flight was 59 seconds. The frame supporting the front rudder was badly broken, but the main part of the machine was not injured at all. We estimated that the machine could be put in condition for flight again in about a day or two."[58] They flew only about ten feet above the ground as a safety precaution, so they had little room to maneuver, and all four flights in the gusty winds ended in a bumpy and unintended "landing". Modern analysis by Professor Fred E. C. Culick and Henry R. Rex (1985) has demonstrated that the 1903 Wright Flyer was so unstable as to be almost unmanageable by anyone but the Wrights, who had trained themselves in the 1902 glider.[59]

QMRLess than a decade after the development of the first practical rotorcraft of any type with the autogyro, in the Soviet Union, Boris N. Yuriev and Alexei M. Cheremukhin, two aeronautical engineers working at the Tsentralniy Aerogidrodinamicheskiy Institut (TsAGI, Russian: Центра́льный аэрогидродинами́ческий институ́т (ЦАГИ), English: Central Aerohydrodynamic Institute), constructed and flew the TsAGI 1-EA single rotor helicopter, which used an open tubing framework, a four blade main rotor, and twin sets of 1.8-meter (5.9 ft) diameter anti-torque rotors; one set of two at the nose and one set of two at the tail. Powered by two M-2 powerplants, up-rated copies of the Gnome Monosoupape rotary radial engine of World War I, the TsAGI 1-EA made several successful low altitude flights. By 14 August 1932, Cheremukhin managed to get the 1-EA up to an unofficial altitude of 605 meters (1,985 feet) with what is likely to be the first successful single-lift rotor helicopter design ever tested and flown.

QMRMicroraptor

From Wikipedia, the free encyclopedia

Microraptor

Temporal range: Early Cretaceous, 125–120 Ma

PreЄЄOSDCPTJKPgN

↓

Microraptor gui holotype.png

Fossil specimen, with white arrows pointing at preserved feathers

Scientific classification e

Kingdom: Animalia

Phylum: Chordata

Order: Saurischia

Suborder: Theropoda

Family: †Dromaeosauridae

Clade: †Microraptoria

Genus: †Microraptor

Xu et al., 2000

Type species

†Microraptor zhaoianus

Xu et al., 2000

Species

M. zhaoianus Xu et al., 2000

M. gui Xu et al., 2003

M. hanqingi Gong et al., 2012

Synonyms

Cryptovolans Czerkas et al., 2002

Microraptor (Greek, μίκρος, mīkros: "small"; Latin, raptor: "one who seizes") was a genus of small, four-winged paravian (possibly dromaeosaurid) dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China. They date from the early Cretaceous Jiufotang Formation (Aptian stage), 125 to 120 million years ago.[1] Three species have been named (M. zhaoianus, M. gui, and M. hanqingi), though further study has suggested that all of them represent variation in a single species, which is properly called M. zhaoianus. Cryptovolans, initially described as another four-winged dinosaur, is usually considered to be a synonym of Microraptor.[2]

Like Archaeopteryx, well-preserved fossils of Microraptor provide important evidence about the evolutionary relationship between birds and dinosaurs. Microraptor had long pennaceous feathers that formed aerodynamic surfaces on the arms and tail but also on the legs. This led paleontologist Xu Xing in 2003 to describe the first specimen to preserve this feature as a "four-winged dinosaur" and to speculate that it may have glided using all four limbs for lift. Subsequent studies have suggested that it is possible Microraptor were capable of powered flight as well.

Microraptor were among the most abundant non-avian dinosaurs in their ecosystem, and the genus is represented by more fossils than any other dromaeosaurid, with possibly over 300 fossil specimens represented across various museum collections.[3]

QMROrion's seven brightest stars form a distinctive hourglass-shaped asterism, or pattern, in the night sky. Four stars—Rigel, Betelgeuse, Bellatrix and Saiph—form a large roughly rectangular shape, in the centre of which lie the three stars of Orion's Belt—Alnitak, Alnilam and Mintaka. Coincidentally, these seven stars are among the most distant that can easily be seen with the naked eye. Descending from the 'belt' is a smaller line of three stars (the middle of which is in fact not a star but the Orion Nebula), known as the hunter's 'sword'.

Many of the stars are luminous hot blue supergiants, with the stars of the belt and sword forming the Orion OB1 Association. Standing out by its red hue, Betelgeuse may nevertheless be a runaway member of the same group.

QMRThe Rig Veda refers to the Orion Constellation as Mriga (The Deer).[15] It is said that two bright stars in the front and two bright stars in the rear are The hunting dogs, the one comparatively less bright star in the middle and ahead of two front dogs is The hunter and three aligned bright stars are in the middle of all four hunting dogs is The Deer (The Mriga) and three little aligned but less brighter stars is The Baby Deer. The Mriga means Deer, locally known as Harnu in folk parlance. There are many folk songs narrating the Harnu. The Malay called Orion' Belt Bintang Tiga Beradik (the "Three Brother Star").[citation needed]

QMRIn Euclidean geometry, a convex quadrilateral with at least one pair of parallel sides is referred to as a trapezoid [1] (pronounced: /ˈtɹæpəzɔɪd/)[2] in American and Canadian English but as a trapezium in English outside North America. The parallel sides are called the bases of the trapezoid and the other two sides are called the legs or the lateral sides (if they are not parallel; otherwise there are two pairs of bases). A scalene trapezoid is a trapezoid with no sides of equal measure,[3] in contrast to the special cases below

QMRIn 1690, the astronomer Johannes Hevelius in his Firmamentum Sobiescianum regarded the constellation Pisces as being composed of four subdivisions:[5]

Piscis Boreus (the North Fish): σ – 68 – 65 – 67 – ψ1 – ψ2 – ψ3 – χ – φ – υ – 91 – τ – 82 – 78 Psc.

Linum Boreum (the North Cord):[5] χ – ρ,94 – VX(97) – η – π – ο – α Psc.

Linum Austrinum (the South Cord):[5] α – ξ – ν – μ – ζ – ε – δ – 41 – 35 – ω Psc.

Piscis Austrinus (the South Fish):[5] ω – ι – θ – 7 – β – 5 – κ,9 – λ – TX(19) Psc.

QMRThe Big Dipper (US) or Plough (UK)[1][2] is an asterism (not a constellation) of seven stars, with four defining a "bowl" or "body" and three defining a "handle" or "head", that is recognized as a distinct grouping in many cultures. These stars are the brightest of the formal constellation Ursa Major; six of them are second magnitude stars, while only Megrez (δ) is of third magnitude. The North Star (Polaris), the current northern pole star and the tip of the handle of the Little Dipper, can be located by extending an imaginary line from Merak (β) through Dubhe (α). This makes it useful in celestial navigation.

QMRUrsa Minor (Latin: "Smaller She-Bear", contrasting with Ursa Major), also known as the Little Bear, is a constellation in the northern sky. Like the Great Bear, the tail of the Little Bear may also be seen as the handle of a ladle, hence the North American name, Little Dipper: seven stars with four in its bowl like its partner the Big Dipper. It was one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and remains one of the 88 modern constellations. Ursa Minor has traditionally been important for navigation, particularly by mariners, because of Polaris being the North Star.

QMRCygnus /ˈsɪɡnəs/ is a northern constellation lying on the plane of the Milky Way, deriving its name from the Latinized Greek word for swan. The swan is one of the most recognizable constellations of the northern summer and autumn, it features a prominent asterism known as the Northern Cross (in contrast to the Southern Cross). Cygnus was among the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations.

QMRThe Northern Cross is a prominent astronomical asterism in the northern hemisphere celestial sphere, corresponding closely with the constellation Cygnus The Swan. It is much larger than the more famous Southern Cross and consists of the brightest stars in Cygnus, Deneb, Sadr, Gienah, Delta Cygni and Albireo. The 'head' of the cross, Deneb, is also part of the Summer Triangle asterism.

Like the Summer Triangle, the Northern Cross is a prominent indicator of the seasons. Near midnight, the Cross lies virtually overhead at mid-northern latitudes during the summer months, it can also be seen during spring in the early morning to the East. In the autumn the cross is visible in the evening to the West until November. It never dips below the horizon at or above 45° north latitude, just grazing the northern horizon at its lowest point at such locations as Minneapolis, Montréal and Turin. From the southern hemisphere it appears upside down and low in the sky during the winter months .

In the 17th-century, German celestial cartographer Johann Bayer's star atlas the Uranometria, Alpha, Beta and Gamma Cygni form the pole of a cross, while Delta and Epsilon form the cross beam. The variable star P Cygni was then considered to be the body of Christ

QMRThe Great Diamond is an asterism. Astronomy popularizer Hans A. Rey called it the Virgin's Diamond. It is composed of the stars Cor Caroli (in Canes Venatici), Denebola (the tail of Leo), Spica (the wheat of Virgo), and Arcturus (in Boötes). It is somewhat larger than the Big Dipper.

The three southernmost stars are sometimes given their own asterism, the Spring Triangle.

Lying within the Great Diamond is the set of stars traditionally assigned to Coma Berenices. Many nearby galaxies, including galaxies within the Virgo Cluster, are located within this asterism, and some of these galaxies can easily be observed with amateur telescopes.

QMRIn non-Western astronomy[edit]

In Australian Aboriginal astronomy, Crux and the Coalsack mark the head of the 'Emu in the Sky' in several Aboriginal cultures, while Crux itself is said to be a possum sitting in a tree and a representation of the sky deity Mirrabooka.[citation needed] Two Pacific constellations also included Gamma Centauri. Torres Strait Islanders in modern-day Australia saw Gamma Centauri as the handle and the four stars as the trident of Tagai's Fishing Spear. The Aranda people of central Australia saw the four Cross stars as the talon of an eagle and Gamma Centauri as its leg.[32]

In ancient Hindu astrology, the modern Crux is referred to as Trishanku.[33]

Various peoples in the East Indies and Brazil viewed the four main stars as the body of a ray.[32] In both Indonesia and Malaysia, it is known as Bintang Pari and Buruj Pari respectively ("ray stars")

The Javanese people of Indonesia called this constellation Gubug pèncèng ("raking hut") or lumbung ("the granary"), because the shape of the constellation was like a raking hut.[34]

The Māori name for the Southern Cross is Te Punga ("the anchor"). It is thought of as the anchor of Tama-rereti's waka (the Milky Way), while the Pointers are its rope.[35] In Tonga it is known as Toloa ("duck"); it is depicted as a duck flying south, with one of his wings (δ Crucis) wounded because Ongo tangata ("two men", α and β Centauri) threw a stone at it. The Coalsack is known as Humu (the "triggerfish"), because of its shape.[36] In Samoa the constellation is called Sumu ("triggerfish") because of its rhomboid shape, while α and β Centauri are called Luatagata (Two Men), just as they are in Tonga. The peoples of the Solomon Islands saw several figures in the Southern Cross. These included a knee protector and a net used to catch Palolo worms. Neighboring peoples in the Marshall Islands saw these stars as a fish.[32]

In Mapudungun, the language of Patagonian Mapuches, the name of the Southern Cross is Melipal, which means "four stars". In Quechua, the language of the Inca civilization, Crux is known as "Chakana", which means literally "stair" (chaka, bridge, link; hanan, high, above), but carries a deep symbolism within Quechua mysticism.[37] Acrux and Mimosa make up one foot of the Great Rhea, a constellation encompassing Centaurus and Circinus along with the two bright stars. The Great Rhea was a constellation of the Bororo people of Brazil. The Mocoví people of Argentina also saw a rhea including the stars of Crux. Their rhea is attacked by two dogs, represented by bright stars in Centaurus and Circinus. The dogs' heads are marked by Alpha and Beta Centauri. The rhea's body is marked by the four main stars of Crux, while its head is Gamma Centauri and its feet are the bright stars of Musca.[38] The Bakairi people of Brazil had a sprawling constellation representing a bird snare. It included the bright stars of Crux, the southern part of Centaurus, Circinus, at least one star in Lupus, the bright stars of Musca, Beta and Delta Chamaeleonis, Volans, and Mensa.[39] The Kalapalo people of Mato Grosso state in Brazil saw the stars of Crux as Aganagi angry bees having emerged from the Coalsack, which they saw as the beehive.[40]

Among Tuaregs, the four most visible stars of Crux are considered iggaren, i.e. four Maerua crassifolia trees.[citation needed] The Tswana people of Botswana saw the constellation as Dithutlwa, two giraffes - Acrux and Mimosa forming a male, and Gacrux and Delta Crucis forming the female.[41]

In popular culture[edit]

The Argentine Air Force acrobatic display team is called Cruz del Sur, the Spanish for "Southern Cross".

In the Victory At Sea suite, Richard Rodgers wrote "Beneath The Southern Cross" to depict the battleships in convoy and the loneliness of the sailors in the Southern Pacific during World War II. This tango melody is also "No Other Love Have I" in the musical "Me and Juliet" and a popular hit for Perry Como during the 1950s.

Cruzeiro Esporte Clube (Crux/Southern Cross Sports Club) is a first class football (soccer) club in Brazil.

Melbourne's Southern Cross Hotel was built and named in 1962 and was one of the city's foremost hotels during the decade. The hotel was demolished in 2005 and replaced by the similarly named office building known as Southern Cross Tower. There is a town in the Western Australian wheatbelt approx 300 km east of Perth called Southern Cross. Melbourne's Spencer Street Station was rebuilt and renamed "Southern Cross Station" in 2006.

The 1974 Australian America's Cup Challenger was named "Southern Cross" KA 4 representing the Royal Perth Yacht Club and was defeated 4-0 sailing off Newport Rhode Island by "Courageous" US26 sailing for the New York Yacht Club. Southern Cross became the trial horse for the 1977 Australian Challenger "Australia" KA 5 representing the Sun City Yacht Club that was defeated 4-0 sailing off Newport Rhode Island by Courageous US26 sailing for the New York Yacht Club.

The Commonwealth Bank of Australia uses a stylized image of the Southern Cross as a corporate logo.

"Southern Cross" is also a 1982 song by the classic rock group Crosby, Stills and Nash, written by Rick Curtis, Michael Curtis, and Stephen Stills. This song was also covered by Jimmy Buffett and is commonly played at his concerts.

After identifying a need for a church for Afrikaans speakers living in the Netherlands, a church was established in Leusden and is known as Suiderkruis Kerk. (Southern Cross Church) There is a town called Suiderkruis (Southern Cross) in the Western Cape province of South Africa. The opening lines of South African composer Koos du Plessis' Christmas carol, 'Somerkersfees' (Summer Christmas) are:

Welkom o stille nag van vrede (Welcome, o silent night of peace)

Onder die suiderkruis (Beneath the Southern Cross)

Zeitgeist: the Movie claims that the Sun can be in the vicinity of Crux: this is seen through the northern hemisphere of the earth.[42][43]

In the 2006 video game Ace Combat X: Skies of Deception, Crux plays a major role in the story of the game and is the name of the player's radio operator.

The 1981 Black Sabbath album Mob Rules features the song "The Sign of the Southern Cross", whose lyrics were written by then member and vocalist Ronnie James Dio.

Mark Twain's travelogue Following the Equator features Twain remarking on the viewing the Southern Cross for the first time, "It is ingeniously named, for it looks just as a cross would look if it looked like something else."

QMRPegasus is a constellation in the northern sky, named after the winged horse Pegasus in Greek mythology. It was one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and remains one of the 88 modern constellations.

With an apparent magnitude varying between 2.37 and 2.45, the brightest star in Pegasus is the orange supergiant Epsilon Pegasi, also known as Enif, which marks the horse's muzzle. Alpha (Markab), Beta (Scheat), and Gamma (Algenib), together with Alpha Andromedae (Alpheratz or Sirrah) form the large asterism known as the Square of Pegasus. Twelve star systems have been found to have exoplanets.

The Babylonian constellation IKU (field) had four stars of which three were later part of the Greek constellation Hippos (Pegasus).[2

Pegasus is dominated by an asterism in the shape of a rough square, although one of the stars, Delta Pegasi or Sirrah, is now officially considered to be part of Andromeda, (α Andromedae) and is more usually called "Alpheratz". Traditionally, the body of the horse consists of a quadrilateral formed by the stars α Peg, β Peg, γ Peg, and α And. The front legs of the winged horse are formed by two crooked lines of stars, one leading from η Peg to κ Peg and the other from μ Peg to 1 Pegasi. Another crooked line of stars from α Peg via θ Peg to ε Peg forms the neck and head; ε is the snout.

QMRA cabochon (/ˈkæbəˌʃɒn/), from the Middle French word caboche (meaning "head"), is a gemstone which has been shaped and polished as opposed to faceted. The resulting form is usually a convex (rounded) obverse with a flat reverse. Cutting en cabochon (French: "in the manner of a cabochon") is usually applied to opaque gems, while faceting is usually applied to transparent stones. Hardness is also taken into account as softer gemstones with a hardness lower than 7 on the Mohs hardness scale are easily scratched, mainly by silicon dioxide in dust and grit. This would quickly make translucent gems unattractive—instead they are polished as cabochons, making the scratches less evident.

In the case of asteriated stones such as star sapphires and chatoyant stones such as cat's eye chrysoberyl, a domed cabochon cut is used to show the star or eye, which would not be visible in a faceted cut.

The usual shape for cutting cabochons is an ellipse. This is because the eye is less sensitive to small asymmetries in an ellipse, as opposed to a uniformly round shape, such as a circle, and because the elliptical shape, combined with the dome, is attractive.[why?] An exception is cabochons on some watches' crowns, which are round.

The procedure is to cut a slab of the rough rock with a slab saw, and next to stencil a shape from a template. The slab is then trimmed to near the marked line using a diamond blade saw—called a trim saw. Diamond impregnated wheels or silicon carbide wheels can be used to grind the rough rock down. Most lapidary workshops and production facilities have moved away from silicon carbide to diamond grinding wheels or flat lap disks.

Once the piece is trimmed it can be "dopped" or completed by hand. "Dopping" is normally done by adhering the stone with hard wax onto a length of wooden dowel called a "dop stick". The piece is then ground to the template line, the back edges may be bevelled, and finally the top is sanded and polished to a uniform dome.

QMRAutumn. The Great Square of Pegasus is the quadrilateral formed by the stars α Pegasi, β Pegasi, γ Pegasi, and α Andromedae, representing the body of the winged horse.[5] It may be glimpsed in its entirety on autumn nights. The asterism was recognized as the constellation ASH.IKU "The Field" on the MUL.APIN cuneiform tablets from about 1100 to 700 BC.[6]

QMRAlpha Pegasi (α Peg, α Pegasi) is the third brightest star in the constellation Pegasus and one of the four stars in the asterism known as the Great Square of Pegasus. It has the traditional name Markab (or Marchab), which comes from an Arabic word مركب markab, "the saddle of the horse", or is mistranscription of Mankib comes from an Arabic phrase منكب الفرس Mankib al-Faras, "(the Star of) the Shoulder (of the Constellation) of the Horse" for β Pegasi.

QMRBeta Pegasi (β Peg, β Pegasi) is a red giant star in the constellation Pegasus. The apparent visual magnitude of this star averages 2.42, making it the second brightest star in the constellation after Epsilon Pegasi. Its traditional name is Scheat,[11] a name that has also been used for Delta Aquarii. According to Richard H. Allen, this name comes from the Arabic Al Sā'id for "the upper arm", or from Sa'd. Arabian astronomers named it Mankib al Faras, meaning the "Horse's shoulder". It forms the upper right corner of the Great Square of Pegasus,[11] a prominent rectangular asterism.

Gamma Pegasi (γ Peg) is a star in the constellation of Pegasus, located at the southwest corner of the asterism known as the Great Square. It also has the traditional name Algenib; confusingly however, this name is also used for Alpha Persei. The average apparent visual magnitude of +2.84[2] puts this at fourth place among the brightest stars in the constellation. The distance to this star has been measured using the parallax technique, yielding a value of roughly 390 light-years (120 parsecs) with a margin of error of 5%.

Alpha Andromedae (Alpha And, α And, α Andromedae), which has the traditional names Alpheratz (or Alpherat from the Arabic word الفرس) and Sirrah (or Sirah), is the brightest star in the constellation of Andromeda. Located immediately northeast of the constellation of Pegasus, it is the northeastern star of the Great Square of Pegasus. Ptolemy considered Alpha Andromedae to be shared by Pegasus, and Bayer assigned it a designation in both constellations: Alpha Andromedae (α And) and Delta Pegasi (δ Peg). When the modern constellation boundaries were fixed in 1930, the latter designation dropped from use.[12]

QMRCapella is the brightest star in the constellation Auriga, the sixth brightest in the night sky and the third brightest in the northern celestial hemisphere, after Arcturus and Vega. Its name is derived from the diminutive of the Latin capra "goat", hence "little goat". Capella also bears the Bayer designation Alpha Aurigae (often abbreviated to α Aurigae, α Aur or Alpha Aur). Although it appears to be a single star to the naked eye, it is actually a star system of four stars in two binary pairs.

British astronomer Hugh Newall had observed its composite spectrum with a four prism spectroscope attached to a 25-inch telescope at Cambridge in July 1899, concluding that it was a binary star system.[15]

QMRA giant planet is any massive planet. They are usually primarily composed of low-boiling-point materials (gases or ices), rather than rock or other solid matter, but massive solid planets can also exist. There are four giant planets in the Solar System: Jupiter, Saturn, Uranus and Neptune. Many extrasolar giant planets have been identified orbiting other stars.

QMROther names for Betelgeuse included the Persian Bašn "the Arm", and Coptic Klaria "an Armlet".[17] Bahu was its Sanskrit name, as part of a Hindu understanding of the constellation as a running antelope or stag.[17] In traditional Chinese astronomy, Betelgeuse was known as 参宿四 (Shēnxiùsì, the Fourth Star of the constellation of Three stars

as the Chinese constellation 参宿 originally referred to the three stars in the girdle of Orion

Dunhuang Star Chart, circa AD 700, showing 参宿四 Shēnxiùsì (Betelgeuse), the Fourth Star of the constellation of Three Stars[141

QMRDeneb (/ˈdɛnɛb/; α Cyg, α Cygni, Alpha Cygni) is the brightest star in the constellation Cygnus, it is one of the vertices of the Summer Triangle and forms the 'head' of the Northern Cross. It is the 19th brightest star in the night sky, with an apparent magnitude of 1.25. A blue-white supergiant, Deneb is also one of the most luminous nearby stars. However, its exact distance (and hence luminosity) has been difficult to calculate; it is estimated to be somewhere between 55,000 and 196,000 times as luminous as the 99.9 SUN FM

QMRRigel has been a known visual binary since at least 1831, when it was first measured by F. G. W. Struve. Though Rigel B is not particularly faint at magnitude 6.7, its closeness to Rigel A—which is over 500 times brighter—makes it a challenging target for telescopes smaller than 150 mm (5.9 in).[22] However a good 7 cm (2.8 in) telescope will reveal Rigel B at 150× power and good seeing. At Rigel's estimated distance, Rigel B is separated from its primary by over 2200 AU (12 lightdays); not surprisingly, there has been no sign of orbital movement, though they share the same proper motion.[20][22] The Rigel system is known to be composed of three stars. A fourth star in the system is sometimes proposed, but it is generally considered that this is a misinterpretation of the main star's variability, which may be caused by physical pulsation of the surface.[22]

QMRChinese asterisms Sze Fūh, the Four Great Canals; Kwan Kew; and Wae Choo, the Outer Kitchen, all lay within the boundaries of Monoceros.[12]

QMRThe Keynesian cross diagram demonstrates the relationship between aggregate demand (shown on the vertical axis) and aggregate supply (shown on the horizontal axis, measured by output).

QMRThe IS–LM model, or Hicks–Hansen model, is a macroeconomic tool that shows the relationship between interest rates and real output, in the goods and services market and the money market (also known as the assets market). The intersection of the "investment–saving" (IS) and "liquidity preference–money supply" (LM) curves is the "general equilibrium" where there is simultaneous equilibrium in both markets.[1] Two equivalent interpretations are possible: first, the IS–LM model explains changes in national income when the price level is fixed in the short-run; second, the IS–LM model shows why the aggregate demand curve shifts.[2] Hence, this tool is sometimes used not only to analyse the fluctuations of the economy but also to find appropriate stabilisation policies.[3]

The model was developed by John Hicks in 1937,[4] and later extended by Alvin Hansen,[5] as a mathematical representation of Keynesian macroeconomic theory. Between the 1940s and mid-1970s, it was the leading framework of macroeconomic analysis.[6] While it has been largely absent from macroeconomic research ever since, it is still the backbone of many introductory macroeconomics textbooks.[7]

The lines cross

Chemistry Chapter

QMRIn chemistry, a tetravalence is the state of an atom with four electrons available for covalent chemical bonding in its valence (outermost electron shell). An example is methane (CH4): the tetravalent carbon atom forms a covalent bond with four hydrogen atoms. The carbon atom is called tetravalent because it forms 4 covalent bonds. A carbon atom has a total of six electrons occupying the first two shells, i.e., the K-shell has two electrons and the L-shell has four electrons. This distribution indicates that in the outermost shell there are one completely filled 's' orbital and two half-filled 'p' orbitals, showing carbon to be a divalent atom. But in actuality, carbon displays tetravalency in the combined state. Therefore, a carbon atom has four valence electrons. It could gain four electrons to form the C4− anion or lose four electrons to form the C4+ cation. Both these conditions would take carbon far away from achieving stability by the octet rule. To overcome this problem carbon undergoes bonding by sharing its valence electrons. This allows it to be covalently bonded to one, two, three or four carbon atoms or atoms of other elements or groups of atoms. Let us see how carbon forms the single, double and triple bonds in the following examples.

A carbon atom has four electrons in its outermost valence shell. So, it needs four more electrons to complete its octet. A carbon atom completes its octet only by sharing its valence electrons with other atoms. As a result, a carbon atom forms four covalent bonds by sharing valence electrons with other atoms. This is known as tetravalency of carbon ("tetra" means four). These four valences of carbon are directed towards four corners of a tetrahedron, and inclined to each other atomic an angle of a 109° 28´.

The carbon atom is assumed to be atomic the center of the tetrahedron. In common use, the four valences of carbon are shown by four bonds around a carbon atom as shown alongside

Methane molecule: Each carbon atom has four electrons in its outermost shell. Thus, it requires four more electrons to acquire a stable noble gas configuration. Each of the hydrogen atoms has only one electron in its outermost shell and requires one more electron to complete its outermost shell (to acquire He configuration). To achieve this, one carbon atom forms four single covalent bonds with four hydrogen atoms.

Carbon dioxide molecule: Each carbon atom has four electrons in its outermost shell and each oxygen atom has six electrons in its outermost shell. Thus, each carbon atom requires four, and each oxygen atom requires two more electrons to acquire noble gas configurations. To achieve this, two oxygen atoms form a double covalent bond with carbon.

Acetylene molecule: Each carbon atom has four electrons in its outermost shell and each hydrogen atom has only one electron in its outermost shell. Two carbon atoms share two electrons each with hydrogen atoms to form single bonds. Each carbon then requires three more electrons to acquire a stable configuration of the nearest noble gas (neon). This is done by mutually sharing three pairs of electrons between the two carbon atoms to form a triple bond.

QMRStudies on Vaska's complex helped provide the conceptual framework for homogeneous catalysis. Vaska's complex, with 16 valence electrons, is considered "coordinatively unsaturated" and can thus bind to one two-electron or two one-electron ligands to become electronically saturated with 18 valence electrons. The addition of two one-electron ligands is called oxidative addition. Upon oxidative addition, the oxidation state of the iridium increases from Ir(I) to Ir(III). The four-coordinated square planar arrangement in the starting complex converts to an octahedral, six-coordinate product. Vaska's complex undergoes oxidative addition with conventional oxidants such as halogens, strong acids such as HCl, and other molecules known to react as electrophiles, such as iodomethane (CH3I).

Vaska's complex binds O2 reversibly:

IrCl(CO)[P(C6H5)3]2 + O2 ⇌ IrCl(CO)[P(C6H5)3]2O2

The dioxygen ligand is bonded to Ir by both oxygen atoms, so-called side-on bonding. In myoglobin and hemoglobin, by contrast, O2 binds "end-on," attaching to the metal via only one of the two oxygen atoms. The resulting dioxygen adduct reverts to the parent complex upon heating or purging the solution with an inert gas, signaled by a colour change from orange back to yellow.[2]

QMRIn chemistry, octahedral molecular geometry describes the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. The octahedron has eight faces, hence the prefix octa. The octahedron is one of the Platonic solids, although octahedral molecules typically have an atom in their centre and no bonds between the ligand atoms. A perfect octahedron belongs to the point group Oh. Examples of octahedral compounds are sulfur hexafluoride SF6 and molybdenum hexacarbonyl Mo(CO)6. The term "octahedral" is used somewhat loosely by chemists, focusing on the geometry of the bonds to the central atom and not considering differences among the ligands themselves. For example, [Co(NH3)6]3+, which is not octahedral in the mathematical sense due to the orientation of the N-H bonds, is referred to as octahedral.[1]

The concept of octahedral coordination geometry was developed by Alfred Werner to explain the stoichiometries and isomerism in coordination compounds. His insight allowed chemists to rationalize the number of isomers of coordination compounds. Octahedral transition-metal complexes containing amines and simple anions are often referred to Werner-type complexes.

Octahedral is made up of two orthogonal quadrants

QMRPolytetrahydrofuran, also called poly(tetramethylene ether) glycol or poly(tetramethylene oxide), is a chemical compound with formula (C

8O)nOH2 or HO-(-(CH2)4O-)n-H. It can be viewed as a polymer of tetrahydrofuran, or as the polyether derived from 1,4-butanediol.

The product is commercially available as polymers of low average molecular weights, between 250 and 3000 daltons. In this form it is a white waxy solid that melts between 20 and 30 °C. The commercial product can be processed further into polymers with molecular weights of 40,000 and higher.

The product is sold under various trade names including Terathane from Invista[1] and PolyTHF from BASF.[2] The BASF plant in Ludwigshafen at one point was producing 250,000 metric tons per year.[3]

Applications[edit]

The main use of polytetrahydrofuran is to make elastic fibers such as spandex (elastan) for stretchable fabrics[4] and for polyurethane resins. The latter are polyurethane prepolymers dissolved in solvent.[5] They are used in the manufacture of artificial leather. These elastomers are either polyurethanes made by reacting PTMEG with diisocyanates, or polyesters made by reacting PTMEG with diacids or their derivatives.[6]

The polymer is also a starting material for thermoplastic polyurethane, thermoplastic polyesters, polyetheramide and cast polyurethane elastomers, used for instance in the wheels of roller skates and skateboards.

Synthesis[edit]

Quadrant Model of Reality

Monday, February 22, 2016

Quadrant Model of Reality Book 10 Science Physics and Chemistry

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