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Cd

Specialty Definition: Cd

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Specialty Definition: Cadmium

(From Wikipedia, the free Encyclopedia)

General
Name, Symbol, Number	Cadmium, Cd, 48
Chemical series	Transition metals
Group, Period, Block	12, 5 , d
Density, Hardness	8650 kg/m3, 2
Appearance	Silvery gray metallic
Atomic Properties
Atomic weight	112.411 amu
Atomic radius (calc.)	155 (161) pm
Covalent radius	148 pm
van der Waals radius	158 pm
Electron configuration	[Kr]4d4d10 5s2
e- 's per energy level	2, 8, 18, 18, 2
Oxidation states (Oxide)	2 (mildly basic)
Crystal structure	Hexagonal
Physical Properties
State of matter	Solid (__)
Melting point	594.22 K (609.93 °F)
Boiling point	1040 K (1413 °F)
Molar volume	13.00 ×1010-3 m3/mol
Heat of vaporization	100 kJ/mol
Heat of fusion	6.192 kJ/mol
Vapor pressure	14.8 Pa at 597 K
Speed of sound	2310 m/s at 293.15 K
Miscellaneous
Electronegativity	1.69 (Pauling scale)
Specific heat capacity	233 J/(kg*K)
Electrical conductivity	13.8 106/m ohm
Thermal conductivity	96.8 W/(m*K)
1st ionization potential	867.8 kJ/mol
2nd ionization potential	1631.4 kJ/mol
3rd ionization potential	3616 kJ/mol
Most Stable Isotopes
iso NA half-life DM DE MeV DP 188Cd 0.89% Cd is stable with 60 neutrons 109Cd {syn.} 462.6 d &epsilon 0.214 109Ag 110Cd 12.49% Cd is stable with 62 neutrons 111Cd 12.8% Cd is stable with 63 neutrons 112Cd 24.13% Cd is stable with 64 neutrons 113Cd {syn.} 7.7 E15 y β- 0.316 113In 113Cdm {syn.} 14.1 y β- IT 0.580 0.264 113In   114Cd 28.73% Cd is stable with 66 neutrons 116Cd 7.49% Cd is stable with 68 neutrons
SI units & STP are used except where noted.

Cadmium is a chemical element in the periodic table that has the symbol Cd and atomic number 48. A relatively rare, soft, bluish-white, toxic transition metal, cadmium occurs with zinc ores and is used largely in batteries.

Notable Characteristics

Cadmium is a soft, malleable, ductile, bluish-white bivalent metal which can be easily cut with a knife. It is similar in many respects to zinc but lends itself to more complex compounds.

The most common oxidation state of cadmium is +2, though rare examples of +1 can be found.

Applications

About three-fourths of cadmium is used in |batteries (esp. Ni-Cd batteries) and most of the remaining one-fourth is used mainly for pigments, coatings and plating, and as stabilizers for plastics. Other uses;

• Used in some of the lowest melting alloys.
• Due to a low coefficient of friction and very good fatigue resistance, it is used in bearing alloys.
• 60% of cadmium finds use in electroplating.
• Many kinds of solder contain this metal.
• As a barrier to control nuclear fission.
• Compounds containing cadmium are used in black and white television phosphors and also in the blue and green phosphors for color television picture tubes.
• Cadmium forms various salts, with cadmium sulfate being the most common. This sulfide is used as a yellow pigment.
• Used in some semiconductors.
• Some cadmium compounds are employed in PVC as stabilizers.

History

Cadmium (Latin cadmia, Greek kadmeia meaning "calamine") was discovered in Germany in 1817 by Friedrich Stromeyer. Stromeyer found the new element within an impurity in zinc carbonate (calamine) and for 100 years Germany remained the only important producer of the metal. The metal was named after the Latin word for calamine since the metal was found in this zinc compound. Stromeyer noted that some impure samples of calamine changed color when heated but pure calamine did not.

Even though cadmium and its compounds are highly toxic, the British Pharmaceutical Codex from 1907 states that cadmium iodide was used as a medicine to treat "enlarged joints, scrofulous glands, and chilblains".

The International Conference on Weights and Measures in 1927 the redefined the meter in terms of a red cadmium spectral line (i.e. 1m = 1.553,164.13 wavelengths). This definition has since been changed (see krypton).

Occurrence

Cadmium-containing ores are rare and when found they occur in small quantities. Greenockite (CdS), the only cadmium mineral of importance, is nearly always associated with sphalerite (ZnSS). Consequently, cadmium is produced mainly as a byproduct from mining, smelting, and refining sulfide ores of zinc, and to a lesser degree, lead and copper. Small amounts of cadmium, about 10% of consumption, are produced from secondary sources, mainly from dust generated by recycling iron and steel scrap. Production in the United States began in 1907 but it was not until after World War I that cadmium came into wide use.

Isotopes

Naturally occurring cadmium is composed of 6 stable isotopes. 27 radioisotopes have been characterized with the most stable being Cd-113 with a half-life of 7.7 quadrillion years, Cd-109 with a half-life of 462.6 days, and Cd-115 with a half-life of 53.46 hours. All of the remaining radioactive isotopes have half-lifes that are less than 2.5 hours and the majority of these have half lifes that are less than 5 minutes. This element also has 8 meta states with the most stable being Cdm-113 (t_½ 14.1 years), Cdm-115 (t_½ 44.6 days) and Cdm-117 (t_½ 3.36 hours).

The isotopes of cadmium range in atomic weight from 96.935 amu (Cd-97) to 129.934 amu (Cd-138). The primary decay mode before the second most abundant stable-isotope, Cd-112, is electron capture and the primary mode after is beta emission. The primary decay product before Cd-112 is element 47 (silver) and the primary product after is element 49 (indium).

Precautions

Cadmium is one of the few elements that has no constructive purpose in the human body. This element and solutions of its compounds are extremely toxic even in low concentrations, and will bioaccumulate in organisms and ecosystems.

Inhaling cadmium laden dust quickly leads to respiratory tract and kidney problems which can be fatal (often from renal failure). Ingestion of any significant amount of cadmium causes immediate poisoning and damage to the liver and the kidneys. Compounds containing cadmium are also carcinogenic.

While working with cadmium it is important to do so under a fume hood to protect against dangerous fumes. Silver solder, for example, which contains cadmium, should be handled with care. Serious toxicity problems have resulted from long-term exposure to cadmium plating baths.

External Links

• WebElements.com - Cadmium
• EnvironmentalChemistry.com - Cadmium

  Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Cadmium."

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CD

(From Wikipedia, the free Encyclopedia)

CD may be:

• the symbol for the chemical element cadmium (Cd)
• the abbreviated form of the SI unit of light intensity, candela
• an initialism for Cash dispenser (at least used in Japan)
• a Unix command, see cd (DOS / Unix Command)
• an abbreviated version of the MS-DOS command chdir - see Cd (DOS / Unix Command)
• an initialism for Certificate of deposit
• an initialism for Ceske Drahy -- Czech Railways
• a designation of a 1960s Panhard race car designed by Charles Deutsch
• an abbreviation of Civil defense
• an abbreviation for cluster of differentiation, (e.g. CD4 or CD8 lymphocytes).
• an initialism for Compact disc; it can also refer to an Enhanced CD.
• an abbreviation of Corps Diplomatique
• the ISO country code for the Democratic Republic of the Congo
• the Internet top-level domain for the Democratic Republic of the Congo, see .cd
• an abbreviation for Circular dichroism

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "CD."

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Cd (DOS / UNIX Command)

(From Wikipedia, the free Encyclopedia)

CD stands for "Change directory."

A Directory is a logical section of a partition used to hold files. A directory is allowed to contain a directory. the CD command can be used to move up into a directory, move back into the parent directory, move all the way back to the root (/ in unix, C:\\ in dos) or move to any given directory name.

For example, in unix:

me@Wiki:~$ ls

workreports games encyclopedia text.txt

me@Wiki:~$ cd games

me@Wiki:games$

The user is now in the "Games" directory.

The same thing in DOS would look like this:

C:\\> dir

workreports Wed Oct 9th 9:01

games Tue Oct 8th 14:32

encyclopedia Mon Oct 1st 10:05

text txt 1903 Thu Oct10th 12:43

C:\\> cd games

C:\\games\\>

This article is a stub. Please help.

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Cd (DOS / UNIX Command)."

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Cd (DOS / Unix Command)

(From Wikipedia, the free Encyclopedia)

The cd command (change directory) in the Unix and DOS operating systems, is used to change the current working directory.

Note that cd has different effects on different operating systems if given with no arguments. For example, if executed without arguments in DOS, the current working directory is printed. If executed without arguments in Unix, then the user is returned to the home directory.

It is a command which is frequently included built into certain shellss such as the Bourne shell, tcsh, and bash. It can be implemented easily with the POSIX C function chdir().

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Cd (DOS / Unix Command)."

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CD-ROM

(From Wikipedia, the free Encyclopedia)

CD-ROM

CD-ROM is an abbreviation for "Compact Disc Read-Only Memory" and a non-volatile optical data storage medium using the same physical format as audio compact discs, readable by a computer with a CD-ROM drive. CD-ROMs are flat, plastic disc with digital information encoded on it in a spiral from the center to the limit, the outside edge.

CDs can either be burned or pressed. Small amounts are burned, larger amounts pressed. The break-even point seems to be somewhere between 100 and 500 copies [1], [1].

Digital information is encoded at near-microscopic size, allowing a large amount of information to be stored. CDs record data as tiny pits (or non-pits) pressed into the lower surface of the plastic disk; a semiconductor laser beam in the player reads these. Most CDs can not be written with a laser, but CD-R discs have colored dyes that can be "burned" (written to) once, and CD-RW (rewritable) discs contain phase-change material that can be written and overwritten several times. Most CD-ROM drives can read CD-R discs; modern drives carrying the MultiRead mark can read CD-RW discs.

The standard CD-ROM can hold approximately 650 megabytes of data, although new technology now allows larger capacities. CD-ROM is popular for distribution of large databases, software and especially multimedia applications. The most common data format on CD holds 650 megabytes of data - about 12 billion bytes per pound weight.

CD-ROMs are read using CD-ROM drives, a now-common computer peripheral, and, in the case of burning, are burned with CD-Recorders, commonly referred to as CD Burners. CD-ROM drives are rated with a speed factor relative to music CDs (1x or 1-speed which gives a data transfer rate of 150 kilobytes per second in the most common data format). Above 12x speed, there are problems with vibration and heat. Constant angular velocity (CAV) drives give speeds up to 20x but due to the nature of CAV the actual throughput increase over 12x is less than 20/12. 20x was thought to be the maximum speed due to mechanical constraints until February 1998, when Samsung Electronics introduced the SCR-3230, a 32x CD-ROM drive which uses a ball bearing system to balance the spinning disc in the drive to reduce noise.

CD-ROM drives may connect to an IDE (ATA) interface, a SCSI interface or a proprietary interface, such as the Panasonic CD interface. Most CD-ROM drives can also play audio CDs. However, there is a move by the recording industry to make audio CDs unplayable on computer CD-ROM drives, to prevent copying the music. This is done by intentionally introducing errors onto the disc that audio players can automatically compensate for. Consumer rights advocates are as of October 2001 pushing to require warning labels on compact discs that do not conform to the official Compact Disc Digital Audio standard (often called the Red Book) to inform consumers of which discs do not permit full fair use of their content.

Manufacturers of CD writers (CD-R or CD-RW) are "encouraged" by the music industry to ensure that every drive they produce has a unique identifier, which will be encoded by the drive on every disc that it records: the RID or Recorder Identification Code. This is a counterpart to the SID - the Source Identification Code, an eight character code beginning with "IFPI" that is usually stamped on discs produced by CD recording plants.

There are several formats used for CD-ROM data, including Green Book CD-ROM, White Book CD-ROM and Yellow Book CD-ROM. ISO 9660 defines a standard file system. UDF format is used on user writable CD-R and CD-RW disks that are intended to be extended or overwritten.

Informative CD-ROMs may contain links to webpages with additional information. To keep them up to date these are sometimes indirect: they link to webpages maintained by the producer of the CD-ROM which contain the links to external webpages.

see also Compact disc, computer hardware, CD-R, CD-RW, DVD-ROM, Enhanced CD, ISO 9660.

Portions of this article are based on a FOLDOC entry

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "CD-ROM."

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Charles Deutsch

(From Wikipedia, the free Encyclopedia)

Charles Deutsch, French aerodynamics engineer and automobile maker, founder of the brand "DB" with René Bonnet, and later of the "CD".

He later founded the SERA vehicle engineering Research and Development Company. Robert Choulet was the most famous disciple of Charles Deutsch.

External link

• http://www.sera-cd.com/

  Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Charles Deutsch."

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Circular dichroism

(From Wikipedia, the free Encyclopedia)

circular dichroism, or CD, is defined as the differential absorption of left and right hand circularly polarized light:

CD = (C_L - C_R).

In general, this kind of phenomenon will be exhibited by any optically active molecule. As a consequence, circular dichroism is exhibited by biological molecules, because of the dextrorotary (sugars) and levulorotary (amino acids) molecules they contain. Noteworthy as well is that secondary structure will also impart a distinct CD absorption to their respective molecules. Therefore, the alpha helix of proteins and the double helix of nucleic acids will have a CD signature representative of their structure.

The ultraviolet CD of proteins can predict their secondary structure.

At the quantum mechanical level, the information content of circular dichroism and optical rotation are identical.

See also:

• optical rotation
• optical activity
• optical isomerism
• magnetic_circular_dichroism
• dichroic

  Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Circular dichroism."

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Compact disc

(From Wikipedia, the free Encyclopedia)

A compact disc.

A compact disc or CD is an optical disc originally used to store music, in the form of digital audio, but now also used as a data storage device. Compact discs are made from a 1.2 mm thick disc of polycarbonate plastic coated with a much thinner aluminium layer which is protected by a film of lacquer. The lacquer can be printed with a label. CDs are available in a range of sizes but the most commonly available is 120 mm in diameter. A 120 mm disc can store about 74 minutes of music or about 650 megabytes of data. Discs that can store about 700 megabytes (80 minutes of music) have become more common. There are also less common 90, 99 and 100 minute discs, but they are not compatible with all CD writers or readers. The format of the disc, known as the 'Red Book' standard, was laid out by the Dutch electronics company Philips, who own the rights to the licensing of the 'CD' logo that appears on the disk. In broad terms the format is a two channel (left and right, for stereo) 16-bit PCM encoding at 44.1 kHz. Reed-Solomon error correction allows the CD to be scratched (to a certain degree) without degradation of the contents.

The information on a standard CD is encoded as a spiral track of "pits" moulded into the top of the polycarbonate layer. Each pit is approximately 125 nm deep by 500 nm wide, and varies from 850 nm to 3.5 μm long. The spacing between the tracks is 1.5 μm. A CD is read by shining light from a 780 nm wavelength semiconductor laser through the bottom of the polycarbonate layer, and monitoring the light reflected by the aluminium coating. The light from the laser forms a spot of approximately 1.7 μm diameter on the metal surface. Since the CD is read through the bottom of the disc, each "pit" appears as an elevated "bump" to the reading light beam. The areas without bumps are known as "land".

Light striking the "land" areas is reflected normally and detected by a photodiode. Light striking a bump, however, undergoes destructive interference with light reflecting from the land surrounding the bump and no light is reflected. This occurs because the height of each bump is one quarter of the wavelength of the laser light (in the polycarbonate medium), leading to a half-wavelength phase difference in light reflecting from the land to that of light reflecting from the bump.

History

The 'CD' was developed in 1980 in cooperation of Sony and Philips. 1982 began the mass production in Langenhagen near Hanover, Germany.

Copy protection

Attempts are currently (early 2002) being made by record companies to market so called 'copy-protected' compact discs. These rely on deliberate errors being introduced into the data recorded on the disc. The intent is that the error-correction in a music player will enable music to be played as normal, while computer CD-ROM drives will fail with errors (though not all current drives fail, and copying software is being adapted to cope with these damaged data tracks.) Philips have stated that such discs, which are written with deliberately degraded data on them which fails the Red Book specification, will not be permitted to have the CD logo on their packaging; and it seems likely that Philips' new models of CD recorders will be designed to be able to record from these 'protected' discs.

Recordability

Compact discs cannot be easily recorded, as they are manufactured by etching a glass plate and using that plate to press metal. However there are also CD-R discs, which can be recorded by a laser beam using a CD-R writer (most often on a computer, though standalone units are also available), and can be played on (most) compact disc players. The recording on a CD-R is permanent - the medium cannot record more than once - so the process is also called "burning" a CD. CD-RW on the other hand is a medium that allows multiple recordings on the same disc over and over again. Many CD-Audio players cannot read CD-RW discs, but more standalone DVD players can read CD-RW than only CD-R discs. These issues are moot, however, when referring to drives installed in computers, as all but the oldest CD-ROM and DVD-ROM drives can read (if not write) CD-R and CD-RWs.

Naming conventions

The correctness of the spellings "disk" and "disc is not trivial: see http://www.bartleby.com/61/16/C0521600.html.

The term EP is used for both a CD and a vinyl record of intermediate play-time.

See also

See also CDDB, Video CD, Laserdisc, Minidisc, DVD, SACD, ECD, FMD, MildDisc

External links

• Oversize CD-R.
• Nero Overburn.

  Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Compact disc."

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ISO 3166-2:CD

(From Wikipedia, the free Encyclopedia)

ISO 3166-2 codes for Democratic Republic of the Congo, formerly called Zaire, which has country code CD. The purpose of this family of standards is to establish a worldwide series of short abbreviations for places, for use on package labels, containers and such. Anywhere where a short alphanumeric code can serve to clearly indicate a location in a more convenient and less ambiguous form than the full place name. US readers may wish to consider them as the equivalent of worldwide zip or postal codes. Within the Wikipedia, the codes from the country pages link to the pages for the locations they identify.

Encoding list

City(1)

CD-KN Kinshasa

Provinces(10)

CD-BN Bandundu
CD-BC Bas-Congo
CD-EQ Équateur
CD-KW Kasai-Occidental
CD-KE Kasai-Oriental
CD-KA Katanga
CD-MA Maniema
CD-NK Nord-Kivu
CD-OR Orientale
CD-SK Sud-Kivu

Decoding list

CD-BC Bas-Congo
CD-BN Bandundu
CD-EQ Équateur
CD-KA Katanga
CD-KE Kasai-Oriental
CD-KN Kinshasa
CD-KW Kasai-Occidental
CD-MA Maniema
CD-NK Nord-Kivu
CD-OR Orientale
CD-SK Sud-Kivu

Newsletters

ISO 3166-2:2002-05-21

See also

• ISO 3166-2, the reference table for all country region codes.
• ISO 3166-1, the reference table for all country codes, as used for domain names on the internet.

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "ISO 3166-2:CD."

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Jerky Boys: The Movie (soundtrack)

(From Wikipedia, the free Encyclopedia)

• CD: Jerky Boys: The Movie
• Year Released: 1995
• See also: Jerky Boys: The Movie
• Label: Atlantic Records
• Genre: Soundtrack

Tracks

1. Accordions & Keyboards - John G. Brennan
2. Gel - Collective Soul
3. 2000 Light Years Away - Green Day
4. Dial A Jam - Coolio & The 40 Thevz
5. Shallow End - Superchunk
6. Four Fly Guys - Hurricane
7. Are You Gonna Go My Way? - Lenny Kravitz
8. Hangin' On The Telephone - L7
9. Beef Jerky - House Of Pain
10. Symptom Of The Universe - Helmet
11. Dirty Dancing - Wu-Tang Clan
12. You Got Me Sick As A Dog - Jerky Boys

    Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Jerky Boys: The Movie (soundtrack)."

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List of people by name: Cd

(From Wikipedia, the free Encyclopedia)

List of people by name: A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z Ca - Cb - Cc - Cd - Ce - Cf - Cg - Ch - Ci - Cj - Ck - Cl - Cm - Cn - Co - Cp - Cq - Cr - Cs - Ct - Cu - Cv - Cw - Cx - Cy - Cz

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "List of people by name: Cd."

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Abbreviations & Acronyms: Cd

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Synonyms within Context: Cd

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Modern Usage: Cd

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Commercial Usage: Cd

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Image Slideshow: Cd

Illustrations: Cd More pictures...

Computer Images: Cd More pictures...

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Photo Album: Cd

Thumbnail	Description & Credit
	Shown is a close up of a slice of a baguette. This photo was part of the interactive CD. Credit: Renee Comet (Photographer).
Source: pictures compiled by the editor from various references; see picture credits.

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Digital Photo Gallery: Cd
 

"CD reflection" by Ovidiu Sopa Commentary: "Some cool colors of a CD."	"CD Universe" by MESH'AL A. Commentary: "Some Compact Disk reflectting beautiful waves of colors."
Source: photographs selected by the editor, with permission from the photographers.

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Sounds Captioned with "Cd".

Play	Caption
	CD skipping.
Source: compiled by the editor from various references; see credits.

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Non-Fiction Usage: Cd

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Usage Frequency: Cd

Source: compiled by the editor from several corpora; see credits.

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Usage in Company Names: Cd

Source: compiled by the editor from Icon Group International, Inc.

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Expressions: Cd

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Frequency of Internet Keywords: Cd

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Modern Translation: Cd

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Derivations: Cd

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Anagrams: Cd