Software industry

2008-02-23T04:46:25Z

72.220.194.85: /* Commercial */

{{globalize}}
{{Expand|date=January 2007}}
[[Image:Packagedsoftwareatretail.jpg|thumb|right|250px|Starting in the 1980s, application software has been sold in mass-produced packages through retailers]]

The '''software industry''' comprises businesses involved in the [[software development|development]], maintenance and [[software publisher|publication]] of [[computer software]]. The software industry started in the mid-1970s at the time of the personal computer revolution. The industry also includes software [[Service (economics)|service]]s, such as training and consultancy. The largest and most profitable of software companies are located in the [[United States]]. As of 2006, the client software industry is dominated by [[Microsoft]]. [[Software Magazine]]'s 500 list in 2005 shows the total amount of revenue brought in by software companies per locale, with the highest being [[California]] due to [[Silicon Valley]] and the amount of [[Fortune 500]] software companies residing in that area. <ref>[http://www.softwaremag.com/SW500/index.cfm?StartRow=1&RowsPer=50&BusCat_Search=&PrimBus_Search=&PrimBusCat_Search=&RankSort=ASC&CompSort=&trk=n&id=5 Software Magazine 500] (2005)</ref>

== Overview ==
There are mainly two types of businesses in the software industry; those developing [[proprietary]] software such as [[Microsoft]], and those developing [[open source]] software. Developing proprietary software is costly and involves software licensing and the need to protect the software from [[cracking]] and [[piracy]].

The main financial return on open source comes from selling services, such as training and support, rather than the software itself. Many contributors to open source software (especially those developing software tools) also feel that there is a significant long-term return in the form of improved resources and capabilities within the software industry. Despite doing much business in properietary software, some companies like [[Sun Microsystems]] and [[IBM]] participate in developing free and open source software to deter from [[monopoly|monopolies]] and take a portion of their [[market share]]. [[Netscape]]'s actions are an example of this, and thus [[Firefox]] has become more popular.

T.Sreenivasa Reddy

== Sectors ==
=== Freeware ===
[[Freeware]] is [[copyright]]ed computer [[software]] which is made available for use free of charge, for an unlimited time, as opposed to [[shareware]] where the user is required to pay (e.g. after some trial period or for additional functionality). Authors of freeware often want to "give something to the community", but also want credit for their software and to retain control of its future development. Sometimes when programmers decide to stop developing a freeware product, they will give the source code to another programmer or release the product's source code to the public as [[free software]].

=== Shareware===
[[Shareware]] is a [[marketing]] method for [[computer software]]. Shareware software is typically obtained free of charge, either by downloading from the Internet or on magazine cover-disks. A user tries out the program, and thus shareware has also been known as "try before you buy". A shareware program is accompanied by a request for payment, and the software's distribution license often requires such a payment.

=== Open source ===
[[Open source]] describes the principles and methodologies to promote open access to the '''production''' and '''design''' process for various goods, products, resources and technical [[conclusions]] or advice. The term is most commonly applied to the [[source code]] of software that is made available to the general public with either relaxed or non-existent [[intellectual property]] restrictions. This allows users to create [[user generated content|user-generated software content]] through either incremental individual effort, or [[collaboration]].

=== Commercial ===
Commercial software is [[computer software]] sold for [[commerce|commercial]] purposes or that serves commercial purposes. Commercial software is most often [[proprietary software]], but [[free software]] is also used as commercial software.<ref>[[Free Software Foundation]]. ''Categories of Free and Non-Free Software''.[http://www.gnu.org/philosophy/categories.html]</ref> All or parts of software packages and services that support commerce are increasingly made available as free software, including products from [[Red Hat]], [[Apple Computer]], [[Sun Microsystems]], and [[Google]]. [[Microsoft Corporation]] uses "commercial software", rather than "proprietary software", to describe their [[business model]].<ref>http://www.microsoft.com/presspass/exec/craig/05-03sharedsource.mspx</ref>

== Size of the Industry ==

[[Software Magazine]]s' ''Software 500 survey'' can be used to gauge the value of the commercial software industry. The ''Software 500 survey'' consists of data of the top 500 software companies, as ranked by [[Software Magazine]]. Total worldwide revenues in 2006 for companies in the ''Software 500'' list were $394 billion, representing a growth of 3.5% from 2005, when total Software 500 revenue was $381 billion.<ref>[http://www.softwaremag.com/L.cfm?Doc=984-10/2006 Software Magazine - 2006 Software 500: Deep Concerns Over Security]</ref>

== See also ==
* [[Professional open-source| Professional Open Source Business Model]]
* [[Software]]
* [[Software development]]
* [[Software publisher]]
* [[Software engineering]]
* [[Software engineering economics]]
* [[World's_largest_software_companies]]

== References ==
<div class="references-small"><references/></div>

== External links ==
* [http://www.sao.org/ Software Association of Oregon website]
* [http://www.siprofessionals.org/ Software Industry Professionals website]
* [http://www.siia.net/ Software and Information Industry Association website]
* [http://www.softwaremag.com/ Software Magazine website]

[[Category:Industries]]
[[Category:Software industry|*]]

[[es:Industria del software]]

Precipitation (chemistry)

2008-02-22T02:23:45Z

72.220.246.136: /* Uses */

'''Precipitation''' is the formation of a [[solid]] in a [[solution]] during a [[chemical reaction]]. When the chemical reaction occurs the solid formed is called the '''precipitate'''. This can occur when an insoluble substance, the '''precipitate''', is formed in the solution due to a reaction or when the solution has been [[supersaturated]] by a compound. The formation of a precipitate is a sign of a chemical change. In most situations, the solid forms ("falls") out of the solute phase, and sinks to the bottom of the solution (though it will float if it is less dense than the solvent, or form a [[suspension (chemistry)|suspension]]).

==Uses==

wiki is mumbo jumbo

==Mechanism==

An important stage of the precipitation process is the onset of [[nucleation]]. The creation of a hypothetical solid particle includes the formation of an interface, which requires some energy based on the relative [[surface energy]] of the solid and the solution. If this energy is not available, and no suitable nucleation surface is available, [[supersaturation]] occurs.

==Representation using chemical equations==

An example of a precipitation reaction: Aqueous silver nitrate (AgNO3) is added to a solution containing potassium chloride (KCl) and the precipitation of a white solid, silver chloride is observed. (Zumdahl, 2005)

:AgNO3(aq) + KCl(aq) → AgCl(s) + KNO3(aq)

The silver chloride(AgCl) has formed a solid, which is observed as a precipitate.

This reaction can be written emphasizing the dissociated ions in a combined solution. This is known as the total ionic equation.
:Ag+(aq) + NO3-(aq) + K+(aq) + Cl-(aq) → AgCl(solid) + K+(aq) + NO3-(aq)

A final way to represent a precipitate reaction is known as a ''net ionic reaction''. In this case, any spectator ions (those which do not contribute to the reaction) are left out of the formula completely. This simplifies the above equations to the following:
:Ag+(aq) + Cl-(aq) → AgCl(s)

==Cation sensitivity==
Precipitate formation is useful in the detection of the type of [[cation]] in [[salt]]. To do this, an [[alkali]] first reacts with the unknown salt to produce a precipitate which is the hydroxide of the unknown salt.

To identify the cation, the color of the precipitate and its solubility in excess are noted.

Similar processes are often used to separate chemically similar elements, such as the [[Alkali earth metals]].

==Digestion==

Digestion, or ''precipitate ageing'', happens when a freshly-formed precipitate is left, usually at a higher temperature, in the solution from which it is precipitated. It results in cleaner and bigger particles.<ref>[http://www.ktf-split.hr/glossary/en_o.php?def=digestion Chemical dictionary definition.]</ref> The physico-chemical process underlying digestion is called [[Ostwald ripening]].

==Coprecipitation==
{{main|coprecipitation}}

Coprecipitation is the carrying down by a precipitate of substances normally soluble under the conditions employed. It is an important issue in chemical analysis, where it is often undesirable, but in some cases it can be exploited. In [[gravimetric analysis]], it is a problem because undesired impurities often coprecipitate with the analyte, resulting in excess mass. On the other hand, in the analysis of trace elements, as is often the case in [[radiochemistry]], coprecipitation is often the only way of separating an element.

==References==
*Zumdahl, Steven S. ''Chemical Principles.'' 4th ed. New York: Houghton Mifflin Company, 2005.
*Mark Smith ''Principles of Science'' 1993

<references/>

==Further reading==
*Banert, T., Brenner, G., Peuker, U. A. (2006), Operating parameters of a continuous sono-chemical precipitation reactor, Proc. 5. WCPT, Orlando Fl., 23.-27. April 2006.

==External links==
{{Commonscat|Solid precipitation}}
* [http://www.hielscher.com/ultrasonics/precipitation_01.htm Continuous Precipitation Using Ultrasonication (e.g. for nano-size magnetite particles)]

[[Category:Chemical processes]]

[[ca:Precipitació (química)]]
[[da:Fældningsreaktion]]
[[de:Fällung]]
[[es:Precipitado]]
[[fr:Précipité]]
[[gl:Precipitación (reacción)]]
[[it:Precipitazione (chimica)]]
[[he:תגובת שיקוע]]
[[nl:Neerslag (scheikunde)]]
[[ja:沈殿]]
[[no:Fellingsreaksjon]]
[[nn:Fellingsreaksjon]]
[[pt:Precipitação (química)]]
[[ru:Преципитат (химия)]]
[[su:Présipitasi]]
[[sv:Utfällning]]
[[zh:沉淀]]

IdeaWazaWiki - User contributions [en]

Software industry

Precipitation (chemistry)