Prism

In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. At least two of the flat surfaces must have an angle between them. The exact angles between the surfaces depend on the application. The traditional geometrical shape is that of a triangular prism with a triangular base and rectangular sides, and in colloquial use "prism" usually refers to this type. Some types of optical prism are not in fact in the shape of geometric prisms. Prisms can be made from any material that is transparent to the wavelengths for which they are designed. Typical materials include glass, plastic and fluorite.

A dispersive prism can be used to break light up into its constituent spectral colors (the colors of the rainbow). Furthermore, prisms can be used to reflect light, or to split light into components with different polarizations.

How prisms work

Light changes speed as it moves from one medium to another (for example, from air into the glass of the prism). This speed change causes the light to be refracted and to enter the new medium at a different angle (Huygens principle). The degree of bending of the light's path depends on the angle that the incident beam of light makes with the surface, and on the ratio between the refractive indices of the two media (Snell's law). The refractive index of many materials (such as glass) varies with the wavelength or color of the light used, a phenomenon known as dispersion. This causes light of different colors to be refracted differently and to leave the prism at different angles, creating an effect similar to a rainbow. This can be used to separate a beam of white light into its constituent spectrum of colors. Prisms will generally disperse light over a much larger frequency bandwidth than diffraction gratings, making them useful for broad-spectrum spectroscopy. Furthermore, prisms do not suffer from complications arising from overlapping spectral orders, which all gratings have.

List of Humanx Commonwealth planets

This is a list of the fictional planets in the Humanx Commonwealth series of novels by Alan Dean Foster.

Alaspin

Alaspin has large jungles surrounded by equally large savannas and river plains; its only notable celestial feature is two moons.

Currently the planet has no sentient race; the native race died out, possibly by racial suicide, over 75,000 years ago leaving behind hundreds of ancient, abandoned cities that have proved a source of fascination to modern xeno-archaeologists.

A variety of lifeforms currently live on Alaspin, most notably the Alaspinian minidrag.

Annubis

Annubis is most notable for the fictional Hyperion forests from which the fictional drug bloodhype is manufactured. In an attempt to eradicate the highly addictive and deadly drug, the trees were burned in 545 A.A. and are thought to be completely destroyed.

The planet first appeared in the novel Bloodhype.

Blasusarr

Blasusarr is the homeworld of the AAnn race and is often called the Imperial Home World. Climate is dry and hot, largely desert, the preferred atmospheric conditions of the AAnn. Beyond this, little is known about Blasusarr other than the fact that it is very well-protected by a detection and space defense network. Its capital city, also the capital of the AAnn Empire, is Krrassin.

Prism (disambiguation)

A prism is a transparent optical component with flat surfaces that refract light.

Prism may also refer to:

Science and mathematics

Government

Media and entertainment

Publications

Music

Jeff Scott Soto

Jeff Scott Soto (born November 4, 1965) is an American rock singer of Puerto Rican descent. He is most well known for being the lead singer for the group Talisman from 1990 till the end of Talisman in 2007, the vocalist on Yngwie Malmsteen's first two albums, and the lead vocalist for Journey on their 2006–2007 tours after Steve Augeri had to leave the band because of an acute throat infection. His style ranges from Hard Rock to Heavy & Power Metal, but he is also influenced by classic soul music singers such as Sam Cooke as well as Journey vocalist Steve Perry, and Freddie Mercury from Queen.

Career

Soto came to prominence in the early 1980s via his involvement with several Yngwie Malmsteen records. The bands Soto has been involved in included Panther, Axel Rudi Pell, Eyes, Talisman, Takara, Humanimal, Human Clay, Kryst The Conqueror, Redlist, The Boogie Knights and Soul Sirkus.

Soto has sung background vocals on several albums by artists such as Lita Ford, Steelheart, Fergie Frederiksen, Glass Tiger, House Of Lords, Stryper, Saigon Kick, and many others.

Dioptrique

La dioptrique (in English Dioptrique, Optics, or Dioptrics), is a short treatise published in 1637 included in one of the Essays written with Discourse on the Method by Rene Descartes. In this essay Descartes uses various models to understand the properties of light. This essay is known as Descartes' greatest contribution to optics, as it is the first publication of the Law of Refraction.

First Discourse: On Light

The first discourse captures Descartes' theories on the nature of light. In the first model, he compares light to a stick that allows a blind person to discern his environment through touch. Descartes says:

Descartes' second model on light uses his theory of the elements to demonstrate the rectilinear transmission of light as well as the movement of light through solid objects. He uses a metaphor of wine flowing through a vat of grapes, then exiting through a hole at the bottom of the vat.

Second Discourse: On Refraction

Descartes uses a tennis ball to create a proof for the laws of reflection and refraction in his third model. This was important because he was using real-world objects (in this case, a tennis ball) to construct mathematical theory. Descartes' third model creates a mathematical equation for the Law of Refraction, characterized by the angle of incidence equalling the angle of refraction. In today's notation, the law of refraction states,

Al-Kindi

Abu Yūsuf Yaʻqūb ibn ʼIsḥāq aṣ-Ṣabbāḥ al-Kindī (Arabic: أبو يوسف يعقوب بن إسحاق الصبّاح الكندي‎, Latin: Alkindus) (c. 801–873 AD), known as "the Philosopher of the Arabs", was a Muslim Arab philosopher, polymath, mathematician, physician and musician. Al-Kindi was the first of the Muslim peripatetic philosophers, and is unanimously hailed as the "father of Islamic or Arabic philosophy" for his synthesis, adaptation and promotion of Greek and Hellenistic philosophy in the Muslim world.

Al-Kindi was a descendant of the Kinda tribe. He was born in Basra and educated in Baghdad. Al-Kindi became a prominent figure in the House of Wisdom, and a number of Abbasid Caliphs appointed him to oversee the translation of Greek scientific and philosophical texts into the Arabic language. This contact with "the philosophy of the ancients" (as Greek philosophy was often referred to by Muslim scholars) had a profound effect on his intellectual development, and led him to write hundreds of original treatises of his own on a range of subjects ranging from metaphysics, ethics, logic and psychology, to medicine, pharmacology, mathematics, astronomy, astrology and optics, and further afield to more practical topics like perfumes, swords, jewels, glass, dyes, zoology, tides, mirrors, meteorology and earthquakes.

OPTICS algorithm

Ordering points to identify the clustering structure (OPTICS) is an algorithm for finding density-based clusters in spatial data. It was presented by Mihael Ankerst, Markus M. Breunig, Hans-Peter Kriegel and Jörg Sander. Its basic idea is similar to DBSCAN, but it addresses one of DBSCAN's major weaknesses: the problem of detecting meaningful clusters in data of varying density. In order to do so, the points of the database are (linearly) ordered such that points which are spatially closest become neighbors in the ordering. Additionally, a special distance is stored for each point that represents the density that needs to be accepted for a cluster in order to have both points belong to the same cluster. This is represented as a dendrogram.

Basic idea

Like DBSCAN, OPTICS requires two parameters: , which describes the maximum distance (radius) to consider, and , describing the number of points required to form a cluster. A point is a core point if at least points are found within its -neighborhood . Contrary to DBSCAN, OPTICS also considers points that are part of a more densely packed cluster, so each point is assigned a core distance that describes the distance to the th closest point: