The Naked Scientists

The Naked Scientists Forum

Author Topic: A-Z of AVIONICS  (Read 449289 times)

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #625 on: 18/03/2007 18:01:13 »
Andrew Alford



Andrew Alford (August 5 1904, Samara, Russia - January 25 1992) was an American electrical engineer and inventor.

who developed antennas for radio navigation systems, now used for VHF omnidirectional range and instrument landing systems.

Alford graduated from the University of California in 1924. He received an honorary doctorate from Ohio University in 1975.


He invented a balanced square antenna named the Alford Loop.

In 1965, the first Master FM Antenna system in the world designed to allow individual FM stations to broadcast simultaneously from one source was erected on the Empire State Building. The original system was co-invented by Alford and Frank Kear.

In 1983 Alford was inducted into the National Inventors Hall of Fame for his invention of the Localizer Antenna System.
 

Offline Karen W.

  • Moderator
  • Naked Science Forum GOD!
  • *****
  • Posts: 31653
  • Thanked: 5 times
  • "come fly with me"
    • View Profile
Re: A-Z of AVIONICS
« Reply #626 on: 18/03/2007 18:09:19 »
Bloody British..LOL Your so fast!

Bacterial
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #627 on: 19/03/2007 14:00:41 »
COLOUR


Color (or colour)is the visual perceptual property corresponding in humans to the categories called red, yellow, white, etc. Color derives from the spectrum of light (distribution of light energy versus wavelength) interacting in the eye with the spectral sensitivities of the light receptors. Color categories and physical specifications of color are also associated with objects, materials, light sources, etc., based on their physical properties such as light absorption, reflection, or emission spectra.

Typically, only features of the composition of light that are detectable by humans (wavelength spectrum from 400 nm to 700 nm, roughly) are included, thereby objectively relating the psychological phenomenon of color to its physical specification. Because perception of color stems from the varying sensitivity of different types of cone cells in the retina to different parts of the spectrum, colors may be defined and quantified by the degree to which they stimulate these cells. These physical or physiological quantifications of color, however, do not fully explain the psychophysical perception of color appearance.

The science of color is sometimes called chromatics. It includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range (that is, what we commonly refer to simply as light).


 

Offline Karen W.

  • Moderator
  • Naked Science Forum GOD!
  • *****
  • Posts: 31653
  • Thanked: 5 times
  • "come fly with me"
    • View Profile
Re: A-Z of AVIONICS
« Reply #628 on: 19/03/2007 14:35:52 »
Diagramming software


Diagramming software
From Wikipedia, the free encyclopedia
(Redirected from Diagramming Software)
Jump to: navigation, search
Diagramming software consists of computer programs that are used to produce graphical diagrams.


[edit] Types of diagramming software
User-generated diagrams. As computer users seek to represent visual information, such as a flowchart, tools such as SmartDraw, Boxily, Dia, OmniGraffle, Microsoft Visio, Inspiration, Fun With MindBook, ConceptDraw V, First Diagramming allow them to express the information in the form of a diagram. Such programs are usually GUI-based and feature WYSIWYG diagram editing. There are also several Diagramming tools available for developers, including Corgent Diagram for Microsoft's .NET Platform and JGraph for the Java platform. Some user-generated diagram software is UML compatible, allowing model-driven translation between graphic representation and functional programming languages.
Automatically generated diagrams. Programs are available as debugger front-ends, computer-aided software engineering (CASE) tools, or profilers. Diagrams are usually automatically generated by the program in this type of software. Tool examples with automatically generated diagrams are Visustin, Project Analyzer and VB Watch.
Retrieved from "http://en.wikipedia.org/wiki/Diagramming_software"

From Wikipedia, the free encyclopedia
(Redirected from Diagramming Software)
Jump to: navigation, search
Diagramming software consists of computer programs that are used to produce graphical diagrams.


[edit] Types of diagramming software
User-generated diagrams. As computer users seek to represent visual information, such as a flowchart, tools such as SmartDraw, Boxily, Dia, OmniGraffle, Microsoft Visio, Inspiration, Fun With MindBook, ConceptDraw V, First Diagramming allow them to express the information in the form of a diagram. Such programs are usually GUI-based and feature WYSIWYG diagram editing. There are also several Diagramming tools available for developers, including Corgent Diagram for Microsoft's .NET Platform and JGraph for the Java platform. Some user-generated diagram software is UML compatible, allowing model-driven translation between graphic representation and functional programming languages.
Automatically generated diagrams. Programs are available as debugger front-ends, computer-aided software engineering (CASE) tools, or profilers. Diagrams are usually automatically generated by the program in this type of software. Tool examples with automatically generated diagrams are Visustin, Project Analyzer and VB Watch.

Retrieved from "http://en.wikipedia.org/wiki/Diagramming_software"
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #629 on: 19/03/2007 15:26:48 »
Where is IKO ?


Gustave Eiffel


Gustave Eiffel built the Eiffel Tower for the Paris World's Fair of 1889, which honored the 100th anniversary of the French Revolution. The World's Fair or Universal Exposition of 1889 (Exposition Universelle de 1889) was a highly successful international exhibition and one of the few world's fairs to make a profit. Its central attraction was the Eiffel Tower, a 300-meter high marvel of iron by Gustave Eiffel.







His brother, AgustuVanotherone Blackpool built the much better Blackpool Tower :








« Last Edit: 19/03/2007 15:29:33 by neilep »
 

Offline Karen W.

  • Moderator
  • Naked Science Forum GOD!
  • *****
  • Posts: 31653
  • Thanked: 5 times
  • "come fly with me"
    • View Profile
Re: A-Z of AVIONICS
« Reply #630 on: 19/03/2007 15:37:02 »
I think he has been gone the whole weekend , Missed him too!LOL
Always wanted to really see the Eiffel tower!

Freud, Sigmund
Freud, Sigmund (froid) [key], 1856–1939, Austrian psychiatrist, founder of psychoanalysis. Born in Moravia, he lived most of his life in Vienna, receiving his medical degree from the Univ. of Vienna in 1881.

His medical career began with an apprenticeship (1885–86) under J. M. Charcot in Paris, and soon after his return to Vienna he began his famous collaboration with Josef Breuer on the use of hypnosis in the treatment of hysteria. Their paper, On the Psychical Mechanism of Hysterical Phenomena (1893, tr. 1909), more fully developed in Studien über Hysterie (1895), marked the beginnings of psychoanalysis in the discovery that the symptoms of hysterical patients—directly traceable to psychic trauma in earlier life—represent undischarged emotional energy (conversion; see hysteria). The therapy, called the cathartic method, consisted of having the patient recall and reproduce the forgotten scenes while under hypnosis. The work was poorly received by the medical profession, and the two men soon separated over Freud's growing conviction that the undefined energy causing conversion was sexual in nature.

Freud then rejected hypnosis and devised a technique called free association (see association), which would allow emotionally charged material that the individual had repressed in the unconscious to emerge to conscious recognition. Further works, The Interpretation of Dreams (1900, tr. 1913), The Psychopathology of Everyday Life (1904, tr. 1914), and Three Essays on the Theory of Sexuality (1905, tr. 1910), increased the bitter antagonism toward Freud, and he worked alone until 1906, when he was joined by the Swiss psychiatrists Eugen Bleuler and C. G. Jung, the Austrian Alfred Adler, and others.

In 1908, Bleuler, Freud, and Jung founded the journal Jahrbuch für psychoanalytische und psychopathologische Forschungen, and in 1909 the movement first received public recognition when Freud and Jung were invited to give a series of lectures at Clark Univ. in Worcester, Mass. In 1910 the International Psychoanalytical Association was formed with Jung as president, but the harmony of the movement was short-lived: between 1911 and 1913 both Jung and Adler resigned, forming their own schools in protest against Freud's emphasis on infantile sexuality and the Oedipus complex. Although these men, and others who broke away later, objected to Freudian theories, the basic structure of psychoanalysis as the study of unconscious mental processes is still Freudian. Disagreement lies largely in the degree of emphasis placed on concepts largely originated by Freud.

He considered his last contribution to psychoanalytic theory to be The Ego and the Id (1923, tr. 1927), after which he reverted to earlier cultural preoccupations. Totem and Taboo (1913, tr. 1918), an investigation of the origins of religion and morality, and Moses and Monotheism (1939, tr. 1939) are the result of his application of psychoanalytic theory to cultural problems. With the National Socialist occupation of Austria, Freud fled (1938) to England, where he died the following year.

Freudian theory has had wide impact, influencing fields as diverse as anthropology, education, art, and literary criticism. His daughter, Anna Freud, was a major proponent of psychoanalysis, developing in particular the Freudian concept of the defense mechanism. Other works include A General Introduction to Psychoanalysis (1910, tr. 1920) and New Introductory Lectures on Psycho-analysis (1933).

Bibliography
http://www.factmonster.com/ce6/people/A0819691.html
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #631 on: 19/03/2007 17:46:40 »
William Gilbert




Dr William Gilbert (Gilberd)
Born    1544
Colchester
Died    1603
London

William Gilbert, or less commonly Gilberd, was born May 24, 1544, Colchester, England and died November 30, 1603, in London, probably of the plague, was an English physician to Elizabeth I and James I and natural philosopher known for his investigations of magnetism and electricity. Gilbert was the originator of the term "electricity" and many regard him as the father of electrical engineering or father of electricity.[1]

His primary work was De Magnete, Magneticisque Corporibus, et de Magno Magnete Tellure (On the Magnet and Magnetic Bodies, and on the Great Magnet the Earth) published in 1600. In this work he describes many of his experiments with his model earth called the terrella. From his experiments, he concluded that the Earth was itself magnetic and that this was the reason compasses pointed north (previously, some believed that it was the pole star (Polaris) or a large magnetic island on the north pole that attracted the compass). In his book, he also studied static electricity using amber; amber is called elektron in Greek, so Gilbert decided to call its effect the electric force.

Gilbert strongly argued that electricity and magnetism were not the same thing. For evidence, he (incorrectly) pointed out that electrical attraction disappeared with heat, magnetic attraction did not. It took James Clerk Maxwell to show electromagnetism is, in fact, two sides of the same coin. Even then, Maxwell simply surmised this in his A Treatise on Electricity and Magnetism after much analysis. By keeping clarity, Gilbert's strong distinction advanced science for nearly 250 years.

Gilbert's magnetism was the invisible force that many other natural philosophers, such as Kepler, seized upon, incorrectly, as governing the motions that they observed. While not attributing magnetism to attraction among the stars, Gilbert pointed out the motion of the skies were due to earth's rotation, and not the rotation of the spheres, 20 years before Galileo, see external reference below.

A unit of magnetomotive force, also known as magnetic potential, was named the gilbert in his honor.

Whilst today he is generally referred to as William Gilbert, he also went under the name of William Gilberd. The latter was used in his and his father's epitaph and, also, in the records of the town of Colchester, which would indicate that this is the most correct - see Biographical Memoir in De Magnete. Also, The Gilberd School in Colchester, named after Gilbert, would seem to confirm this.
 

Offline Karen W.

  • Moderator
  • Naked Science Forum GOD!
  • *****
  • Posts: 31653
  • Thanked: 5 times
  • "come fly with me"
    • View Profile
Re: A-Z of AVIONICS
« Reply #632 on: 19/03/2007 18:10:47 »
HyperlinkFrom Wikipedia, the free encyclopedia
Jump to: navigation, search
A hyperlink (often referred to as simply a link), is a reference or navigation element in a document to another section of the same document, another document, or a specified section of another document, that automatically brings the referred information to the user when the navigation element is selected by the user. As such it is similar to a citation in literature, but with the distinction of automatic instant access. Combined with a data network and suitable access protocol, a computer can be instructed to fetch the resource referenced.

Hyperlinks are part of the foundation of the World Wide Web created by Tim Berners-Lee, but are not limited to HTML or the web. Hyperlinks may be used in almost any electronic media.

HREF is an acronym for Hypertext REFerence, as used in HTML.

http://en.wikipedia.org/wiki/Hyperlink
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #633 on: 19/03/2007 21:18:07 »
Ice Cube Trays

An American physician, John Gorrie, built a refrigerator in 1844 to make ice to cool the air for his yellow fever patients. Dr. Gorrie may have also invented the first ice cube tray in its current form.

Fred W. Wolf Jr. invented a refrigerating machine called the DOMELRE or DOMestic ELectric REfrigerator, in 1914. The DOMELRE was not successful, however, it did have an ice cube tray and inspired later refrigerators to have trays as well.

The first flexible stainless steel, all-metal ice tray was invented by Guy L. Tinkham in 1933. The tray flexed sidewise to eject the ice cubes.

    “Flexing the tray cracks the ice into cubes corresponding to the division points in the tray, and then forces the cubes up and out. Pressure forcing the ice out is due to the 5-degree draft on both sides of the tray.”

The inventor was the then vice president of the General Utilities Mfg. Co., a company that produced household appliances. The McCord ice tray as it was called cost $0.50 in 1933.




1932 Patent - Ice Cube Tray - Newman
 

Offline iko

  • Neilep Level Member
  • ******
  • Posts: 1626
  • Thanked: 1 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #634 on: 19/03/2007 22:13:48 »
« Last Edit: 26/03/2007 18:03:59 by iko »
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #635 on: 20/03/2007 18:55:15 »
Knee

In human anatomy, the knee is the lower extremity joint connecting the femur and the tibia. Since in humans the knee supports nearly the entire weight of the body, it is vulnerable both to acute injury and to the development of osteoarthritis.
Function of the knee

The knee functions as a living, self-maintaining, biologic transmission, the purpose of which is to accept and transfer biomechanical loads between the femur, tibia, patella, and fibula (The previous sentence is ambiguous, and may be correct, but no one should be of the impression that the fibula is part of the knee joint). In this analogy the ligaments represent non-rigid adaptable sensate linkages within the biologic transmission. The articular cartilages act as bearing surfaces, and the menisci as mobile bearings. The muscles function as living cellular engines that in concentric contraction provide motive forces across the joint, and in eccentric contraction act as brakes and dampening systems, absorbing loads.




 

Offline iko

  • Neilep Level Member
  • ******
  • Posts: 1626
  • Thanked: 1 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #636 on: 20/03/2007 21:27:31 »
Lymphoblastic Leukemia  (Acute)


A-C) Bone marrow aspirates from pediatric patients with acute lymphoblastic leukemia.
Courtesy James Downing
   
http://www.genomenewsnetwork.org/gnn_images/news_content/04_02/leukemia/leuk_3.jpg
http://www.danmedbul.dk/Dmb_2006/0106/0106-artikler/DMB3783-4.jpg
« Last Edit: 26/03/2007 18:05:42 by iko »
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #637 on: 20/03/2007 22:52:53 »
Marshmallow




Pink marshmallows.

The marshmallow is a confection that, in its modern form, consists of sugar or corn syrup, beaten egg whites, gelatin that has been pre-softened in water, gum arabic, and flavorings, whipped to a spongy consistency. The traditional recipe used an extract from the mucilaginous root of the marshmallow plant, a shrubby herb (Althaea officinalis), instead of gelatin; the mucilage performed as a cough suppressant.

Commercial marshmallows are a late 19th century innovation. Since Alex Doumak's patented extrusion process of 1948, marshmallows are extruded as soft cylinders, cut in sections and rolled in a mix of finely powdered cornstarch and confectioner's sugar.

Marshmallows are popular with children and adults alike, and are eaten with or without accompaniments. In the United States and elsewhere, marshmallows are also used in hot chocolate or café mocha (mochachino), Mallomars, in Peeps and other candy, on top of candied sweet potatoes during Thanksgiving, in Rice Krispie treats, in ice cream flavors such as Rocky road, and several other foodstuffs.
 

Offline Karen W.

  • Moderator
  • Naked Science Forum GOD!
  • *****
  • Posts: 31653
  • Thanked: 5 times
  • "come fly with me"
    • View Profile
Re: A-Z of AVIONICS
« Reply #638 on: 21/03/2007 03:13:35 »
Narcolepsy
From Wikipedia, the free encyclopedia
Jump to: navigation, search
For other uses, see Narcolepsy (disambiguation).
Narcolepsy
Classification & external resources ICD-10 G47.4
ICD-9 347
OMIM 161400
DiseasesDB 8801
eMedicine neuro/522 
Narcolepsy is a neurological condition most characterized by Excessive Daytime Sleepiness (EDS). A narcoleptic will most likely experience disturbed nocturnal sleep, confused with insomnia, and disorder of REM or rapid eye movement sleep. It is a type of dyssomnia
« Last Edit: 21/03/2007 03:15:58 by Karen W. »
 

Offline iko

  • Neilep Level Member
  • ******
  • Posts: 1626
  • Thanked: 1 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #639 on: 21/03/2007 18:20:03 »
Oxyacetylene torch


5500 F Oxyacetylene Torch Test of Candidate Shuttle
Solid Rocket Motor Thermal Barrier

from:   http://www.grc.nasa.gov/WWW/structuralseal/fixtures/index.htm
« Last Edit: 26/03/2007 18:06:23 by iko »
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #640 on: 22/03/2007 00:20:24 »
PURPLE







Fragment of an actual Purple machine from the Japanese embassy in Berlin, obtained by the United States at the end of World War II.

In the history of cryptography, 97-shiki oobun Inji-ki  ("System 97 Printing Machine for European Characters") or Angooki Taipu-B  ("Type B Cipher Machine"), codenamed PURPLE by the United States, was a diplomatic cryptographic machine used by the Japanese Foreign Office just before and during World War II. The machine was an electromechanical stepping-switch device.

The information gained from decryptions was eventually code-named Magic within the US government.

The codename "PURPLE" referred to binders used by US cryptanalysts for material produced by various systems; there had been a RED machine used by the Japanese Foreign Office, and purple was the next available color. The Japanese also used CORAL and JADE stepping-switch systems. PURPLE was a successor to, and improvement on, both the RED machine and what the Americans called the "M machine" (used in some embassies and consulates by attachés).
 

Offline Karen W.

  • Moderator
  • Naked Science Forum GOD!
  • *****
  • Posts: 31653
  • Thanked: 5 times
  • "come fly with me"
    • View Profile
Re: A-Z of AVIONICS
« Reply #641 on: 22/03/2007 03:09:11 »
 

QUINOLINE

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Quinoline

 
Chemical formula C9H7N
Molecular mass 129.16 g/mol
CAS number [91-22-5]
Density 1.093 g/ml
Melting point −15 °C
Boiling point 238 °C
SMILES C1(N=CC=C2)=C2C=CC=C1
Disclaimer and references
Quinoline, also known as 1-azanaphthalene, 1-benzazine, or benzopyridine, is a heterocyclic aromatic organic compound. It has the formula C9H7N and is a colourless hygroscopic liquid with a strong odour.

As it ages, if exposed to light, the liquid tends to become yellow and later brown. It is only slightly soluble in water but dissolves readily in many organic solvents.

Quinoline is an intermediate in metallurgical processes and in dye, polymer, and agrochemical production. It is also a preservative, disinfectant, and solvent.

It is toxic: short-term exposure to the vapour causes irritation of the nose, eyes, and throat as well as dizziness and nausea. Longer-term effects are uncertain, but quinoline has been linked to liver damage.


[edit] Isolation and synthesis
Quinoline is naturally found in coal tar and was first extracted from this source in 1834 by F. Runge. It can be prepared using various methods:

Combes quinoline synthesis using anilines and β-diketones.
Conrad-Limpach synthesis using anilines and β-ketoesters.
Doebner-Miller reaction using anilines and α,β-unsaturated carbonyl compounds.
Friedländer synthesis using 2-aminobenzaldehyde and acetaldehyde.
Skraup synthesis using ferrous sulfate, glycerol, aniline, nitrobenzene, and sulfuric acid.
Povarov reaction using an aniline, a benzaldehyde and an activated alkene.
Camps quinoline synthesis utilizing an o-acylaminoacetophenone and hydroxide
 



Part two

« Last Edit: 23/03/2007 02:11:34 by Karen W. »
 

Offline iko

  • Neilep Level Member
  • ******
  • Posts: 1626
  • Thanked: 1 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #642 on: 22/03/2007 10:45:42 »
« Last Edit: 26/03/2007 18:07:04 by iko »
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #643 on: 22/03/2007 13:29:39 »
Viktor Schauberger (30 June 1885–25 September 1958) was an Austrian forester/forest warden, naturalist, philosopher and inventor.

The inventor of what he called "implosion technology", Schauberger developed his own highly idiosyncratic theories based on fluidic vortices. Very little of Schauberger's work has received mainstream acceptance, and the bulk of his work would likely be classified as pseudo-science.


Early years

Viktor Schauberger was born in Holzschlag, Austria, to a long line of Austrian foresters. Creek and river flow fascinated him during his youth. He went on to develop a basic theory that contains a two fold movement principle for such phenonomena.

In 1926, he undertook research at a timber flotation installation in Neuberg an der Mürz in Styria. In 1929, Schauberger submitted his first applications for patents in the fields of water engineering and turbine construction. He conducted research on how to artificially generate centripetal movement in various types of machines. He proposed a means of utilising hydroelectric power by a jet turbine. The log flumes used for timber flotation allegedly disregarded the Law of Archimedes, i.e. Schauberger was allegedly able to transport heavier-than-water objects, by creating a centripetal movement (making the timber spin around its own axis, by special guiding-vanes which caused the water to spiral)

World War II

During World War II, Schauberger developed his concepts of vortex dynamics under, he claimed, duress and, he claimed, at the behest of Germany's SS.[citation needed] In 1941 he was confined to a mental hospital in Mauer-Öhling under, he later claimed, continuous observation by the SS.[citation needed] He ran a laboratory at Mauthausen concentration camp with twenty to thirty scientists under his supervsion. He claimed that in Augsburg he worked with Messerschmidt on engine cooling systems, and corresponded with designer Heinkel about aircraft engines.[citation needed] In 1944, Schauberger developed his Repulsine machines at the little known SS-run Technical College of Engineering at Rosenhügel in Vienna.[citation needed] He produced several prototypes, but the Russian and American military confiscated his work at the end of the war.[citation needed] After the war, Schauberger worked on a concept involving perpetual motion leading to water-based power generation through vortex action, in a closed cycle.

Later years

In 1958, Schauberger returned to Austria, after negotiations with an American company.[citation needed] He died in Linz, Austria, on September 25.
 

Offline iko

  • Neilep Level Member
  • ******
  • Posts: 1626
  • Thanked: 1 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #644 on: 22/03/2007 14:57:33 »
Thermionic valve



Diodes and triodes

John Ambrose Fleming had worked for Edison; in 1904, as scientific adviser to the Marconi company, he developed the "oscillation valve" or kenotron. Later known as the Fleming Valve and then the diode, it allowed electric current to flow in only one direction, enabling the rectification of alternating current. Its operation is described in greater detail in the previous section.

In 1907 Lee De Forest placed a bent wire serving as a screen, later known as the "grid" electrode, between the filament and plate electrode. As the voltage applied to the grid was varied from negative to positive, the number of electrons flowing from the filament to the plate would vary accordingly. Thus the grid was said to electrostatically "control" the plate current. The resulting three-electrode device was therefore an excellent and very sensitive amplifier of voltages.

more from:   http://en.wikipedia.org/wiki/Vacuum_tube   

 

« Last Edit: 25/03/2007 23:01:29 by iko »
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #645 on: 22/03/2007 17:44:11 »
Ultra Luminous Infrared Galaxies (ULIRG)

A type of galaxy which is very bright when observed at infrared wavelengths. They were discovered by the IRAS satellite. Astronomers are now investigating the cause of their enormous infrared luminosity.
 

Offline iko

  • Neilep Level Member
  • ******
  • Posts: 1626
  • Thanked: 1 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #646 on: 22/03/2007 18:18:19 »
Vortex  (turbulence)


Turbulence

From Wikipedia, the free encyclopedia

In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic, stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time. Flow that is not turbulent is called laminar flow. The (dimensionless) Reynolds number characterizes whether flow conditions lead to laminar or turbulent flow; e.g. for pipe flow, a Reynolds number above about 2300 will be turbulent.

Consider the flow of water over a simple smooth object, such as a sphere. At very low speeds the flow is laminar, i.e., the flow is smooth (though it may involve vortices on a large scale). As the speed increases, at some point the transition is made to turbulent ("chaotic") flow. In turbulent flow, unsteady vortices appear on many scales and interact with each other. Drag due to boundary layer skin friction increases. The structure and location of boundary layer separation often changes, sometimes resulting in a reduction of overall drag. Because laminar-turbulent transition is governed by Reynolds number, the same transition occurs if the size of the object is gradually increased, or the viscosity of the fluid is decreased, or if the density of the fluid is increased.


...

http://en.wikipedia.org/wiki/Turbulence
« Last Edit: 26/03/2007 18:08:08 by iko »
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #647 on: 22/03/2007 18:23:51 »
Wirtanen (comet)

Periodic comet which orbits the Sun once every 5.45 years. Discovered in 1948 at the Lick Observatory, California, by Carl A. Wirtanen. It is a so-called `Jupiter-type' comet, whose orbit is strongly influenced by that planet. Perihelion is at 159 million km (1.06 AU) from the Sun, i.e. just outside the orbit of the Earth. Aphelion is at a distance of about 768 million km (5.13 AU), near the orbit of Jupiter. Target of ESA's Rosetta mission, which will go into orbit around the nucleus and deploy a lander on its surface.

   

THIS IS THE ACTUAL COMET !!
 

Offline iko

  • Neilep Level Member
  • ******
  • Posts: 1626
  • Thanked: 1 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #648 on: 22/03/2007 20:54:14 »
Xeroderma pigmentosum




Pathophysiology: Cleaver's seminal work in 1968 elucidated the pathophysiology of XP by demonstrating defective DNA repair. Further studies of this defect led to significant progress in the understanding of nucleotide excision repair (NER) mechanisms under normal and pathologic conditions.
UV radiation induces cross-linking (dimerization) between thymine nucleotides.
After exposure to UV light, normal cultured cells identify and excise the UV-induced thymine dimers and insert undamaged nucleotides after DNA synthesis and ligation. This repair process, known as unscheduled DNA synthesis, is deficient in XP. Cell complementation analysis of cultured cells from patients with XP demonstrated that XP was genetically heterogeneous for the ability to repair UV-induced thymine dimers.
Fibroblasts from different patients with XP were fused, and DNA repair after UV exposure was assayed. Correction of DNA repair deficiency in the fused cells indicates that each cell line has a unique abnormality of DNA repair. This finding led to identification of 7 specific complementation groups (A through G).
The genes that are responsible for defective NER in each XP complementary group are highly conserved; homologous genes have been discovered in several species ranging from yeast to mammals.
Two overlapping pathways for NER have been proposed: the rapid transcription-coupled repair directed at the transcribed strand and slower global genome repair, which also includes the nontranscribed strand. Most XP complementary groups are defective in both pathways. The complementary group C (XP-C) is a notable exception in which only global genome repair is defective.

The XP variant complementation group (XP-V) has normal unscheduled DNA synthesis after UV exposure. However, the ability to repair DNA is reduced after adding caffeine to cultured cells. This defect is caused by mutations in the (pol)eta polymerase, which initiates translesion synthesis of UV-damaged DNA in an error-free manner.

XP is a multisystem disorder; sun-exposed skin and eyes (ie, eyelids, conjunctivae) are the most affected tissues. Cutaneous photosensitivity and early development of skin cancer is caused by defective DNA repair.

CNS involvement is due to premature neuronal death.

Necrosis in tissues that are not exposed to UV light suggests that these cells in patients with XP are unable to repair DNA damage from other mutagens (eg, reactive oxygen species, other free radicals). Neurodegeneration probably results from accumulating mutations due to cells' inability to repair DNA damage. Increased oxidative damage in neurons due to abnormal function of free radical scavengers, such as superoxide dismutase, has been suggested.

The presence of neurologic abnormalities correlates with the degree of NER repair defect; patients with the greatest impairment of DNA repair are more prone to develop neurodegeneration.

Pathologic studies showed diffuse neuronal loss without other histologic hallmarks. Selective degeneration of dopaminergic neurons has been reported in some patients who were affected neurologically. Diffuse axonal loss was seen in the peripheral nerves in patients with clinical evidence of polyneuropathy.


Frequency:
In the US: XP-C and XP-D are the most common complementary forms, representing 30% and 20% of all XP cases, respectively. XP-A is rare.
Internationally: The worldwide frequency of XP is estimated at 1 case in 250,000 population. Frequencies of complementary groups vary significantly in different populations. XP-A accounts for as many as 40% of all cases in Japan. Other complementary groups, with the exception of XP-V (in which all patients have only dermatologic manifestations), are rare. For example, only 3 cases of the XP-B type have been reported.
Mortality/Morbidity:
Skin cancer represents the major morbidity in XP.
The median age of the first cutaneous cancer in XP (most commonly basal cell or squamous cell carcinoma) is 8 years. In striking contrast, the mean age for squamous cell carcinoma in the general population is 58 years.
The incidence of malignant melanoma in patients with XP who are younger than 20 years is 2000-fold higher than in an age-matched US population.
Skin tumors are typically multiple, and patients with as many as 100 tumors have been reported. This may result in disfigurement in severely affected subjects.
Keratitis, together with squamous cell tumors of the conjunctiva and corneoconjunctival junction, is a major source of ophthalmologic morbidity.
Other malignancies also occur at increased frequency in patients with XP. The frequency of inner organ neoplasms, including malignant brain tumors, is estimated to be increased 20-fold compared to subjects without XP.
Mental retardation (or dementia in subjects with adult-onset neurologic deterioration), hearing loss, spasticity, ataxia, and polyneuropathy are the most common morbidity factors in the subset of patients who have with neurologic impairment.
As many as 50% of patients with XP-D manifest neurologic deterioration. Neurologic involvement is rare in patients with XP-C, the most common complementary group in the United States.
Seizures are common and epilepsy may be present in almost 25% of all patients.
Neurologic symptoms are progressive and may result in severe disability.
Many patients become bedridden and incontinent. Some have significant cachexia in the terminal stages despite adequate caloric intake.
Urinary tract infection, sepsis, and aspiration pneumonia are potential complications.
Patients with early onset of neurologic symptoms tend to have more profoundly defective DNA repair, making them more susceptible to skin and inner organ tumors.
Kraemer et al constructed the Kaplan-Meier survival curve for patients with XP. The following were estimated:
90% probability of surviving to age 13 years
80% probability of surviving to 28 years
70% probability surviving to 40 years
Overall, life expectancy of patients with XP reduced by 30 years
Various comorbid cancers usually cause death.
Race: All ethnic groups are affected similarly.
Sex: Both sexes are affected equally.
Age: Only 5% of patients manifest the first symptoms after age 14 years.
The median age of symptom onset is approximately 2 years.

...

from:    http://www.emedicine.com/neuro/topic399.htm


« Last Edit: 26/03/2007 18:09:45 by iko »
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: A-Z of AVIONICS
« Reply #649 on: 22/03/2007 22:50:46 »
Yawn

A dog yawning

A yawn (synonyms chasma, oscitation from the Latin verb oscitare, to open the mouth wide[1]) is a reflex of deep inhalation and exhalation associated with being tired, with a need to sleep, or from lack of stimulation. Pandiculation is the term for the act of stretching and yawning. Yawning is a powerful non-verbal message with several possible meanings, depending on the circumstances. It is also claimed to help increase the state of alertness of a person. The exact causes of yawning are still unknown.

Origin of the word

The word "yawn" has evolved from the Middle English word yanen, an alteration of yonen or yenen, which in turn comes from the Old English geonian.




A Yawning cat !
 

The Naked Scientists Forum

Re: A-Z of AVIONICS
« Reply #649 on: 22/03/2007 22:50:46 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums