Marspedia - User contributions [en]

Teflon

2013-06-05T16:14:59Z

ChristiaanK: Created article

{{stub}}
'''Teflon''' is a [[polymer]] which is widely used in the aerospace industry because it does not [[outgas]] much<ref name=Antunes1>S. Antunes - ''DIY satellite platforms: Building a space-ready general base picosatellite for any mission'' 2012. ISBN 978-1-449-31060-8 p. 29</ref>.
==References==
<references />
[[Category:Material]]

Outgassing

2013-06-05T16:11:59Z

ChristiaanK: Link

'''Outgassing''' is an alternative name for sublimation, the process of a solid material turning into a gas due to insufficient pressure (at a given temperature) to fully maintain its solid state.<ref name=Antunes2>S. Antunes - ''Surviving orbit the DIY way: Testing the limits your satellite can and must match'' 2012. ISBN 978-1-449-31062-2 pp. 10, 30, 38.</ref> In the aerospace industry, organic materials are especially prone to this phenomenon.<ref name=Tobiska>W.K. Tobiska - ''The space environment'' in J.R. Wertz, D.F. Everett & J.J. Puschell, eds. ''Space mission engineering: The new SMAD''. 2011. ISBN 978-1-881883-15-9 p. 127.</ref>

==Implications==
*An outgassing material is being eroded<ref name=Antunes2 />, which can decrease the life expectancy of spacecraft components.
*An outgassing material may condense on other spacecraft surfaces, which can impair sensor performance or change the conductivity near or on sensitive electronics.<ref name=Antunes2 />

==Countermeasures==
*Use materials with a low tendency to outgas, such as [[Teflon]]<ref name=Antunes1>S. Antunes - ''DIY satellite platforms: Building a space-ready general base picosatellite for any mission'' 2012. ISBN 978-1-449-31060-8 p. 29</ref>.
*Cooling a material reduces outgassing.
*Keeping a material under higher external pressure reduces outgassing.
*Components can be treated according to NASA's [[thermal-vacuum bakeout]] process. (In essence, this means that they are allowed to outgas under slowly increasing temperature. The material will then be less prone to future outgassing withing this temperature range.) It is important that components be baked out separately before being integrated, otherwise they may contaminate each other in the very ways we are trying to avoid.<ref name=Antunes2 />

==Open issues==
The Martian atmosphere has a pressure significantly lower than the +/- 250 torr used in some thermal vacuum chambers for DIY satellite building<ref name=Antunes2 />. While the temperature is lower, this would seem to indicate that many common materials are not sufficiently vacuum-safe to be used on Mars without treatment.

What degree of outgassing that could be expected on Mars, for materials and equipment produced in a colony?

==References==
<references />

[[Category:Hazards]]

Fungi

2013-06-05T16:07:53Z

ChristiaanK: Expanded

'''Fungi''' are eukaryotic organisms closely related to animals. The study of fungi is known as '''mycology'''.

Some fungi are edible and could be grown for [[food]] in a Martian [[colony]]. Fungi, especially some sorts of mildew, are certainly of great use in the artificial ecosystem of a [[greenhouse]], since they are involved in the [[compost|decaying process]].

Some [[human|people]] have an allergy against the spores of mildew, and patients with depressed [[immune system]] can suffer from a fungus infection. As yet, the development of the human immune system under Martian [[gravity]] and [[house|inhouse]] conditions is unclear.

==Cellular biology==
===Cell wall===
Fungal cells have cell walls which may be composed of several glucose [[polymer|polymers]]. For example, chitin (chains of acetylglucosamine joined by [[polysaccharide|<math>\beta ( 1 \rightarrow 4 )</math> links]]) or, as in yeast, callose (which is a glucose chain which differs from cellulose only in that it uses <math>\beta ( 1 \rightarrow 3 )</math> links where cellulose uses <math>\beta ( 1 \rightarrow 4 )</math> links<ref name=Wolfe>S.L. Wolfe - ''Mollecular and cellular biology'' 1993. Wadsworth. ISBN 0-534-12408-9. pp. 17-18, 288-289, 514-517.</ref>.

===Cytoskeleton===
Like all protozoa, animals and plants, fungi have cytoskeletal structures containing microtubules and microfilaments supporting the cytoplasm inside their cells<ref name=Wolfe />. In some fungi there are also intermediate filaments, though not to the same extent as in animals<ref name=Wolfe />. 
The microtubules can be thought of as analogous to the human skeleton, as they maintain the positions of major organelles within the cell<ref name=Wolfe /> Furthermore, the microfilaments and microtubules are responsible for movement in eukarytic cells. This is achieved when the individual polymers slide across one another to create an overall lengthening or contraction of the structure<ref name=Wolfe />. 
It is worth noting that microgravity affects the cytoskeleton<ref name=Lewis_HughesFulford>M.L. Lewis & M. Hughes-Fulford - ''Cellular responses to spaceflight'' 1997. (In S.E. Churchill, ''ed.'' - ''Fundamentals of space life sciences''. Krieger. ISBN 0-89464-051-8) Vol 1. pp. 21-36.</ref>, so fungi could, in principle, be negatively affected by a journey to Mars. While the matter is of academic interest, fungi would almost certainly be much less harmed by a return to gravity than humans and no mission would therefore be compromised. It is even possible that fungi may grow more readily in microgravity, as some primitive eukaryotes do<ref name=Lewis_HughesFulford />, though that is unlikely as the positive effect is at least mostly due to reduced energy expenditure during movement.
==Mushrooms==
'''Mushrooms''' are the "fruiting bodies" of certain fungi or, more formally, the sporulating organs of certain complex fungi. The word '''toadstool''' is sometimes used in informal conversation to refer to inedible mushrooms. Mushrooms are complete proteins, and their nutritional value are in some respects (such as protein quality) in-between those of plant and animal foods. This makes them a potentially very valuable food source in spaceflight. 
===Morphology===
WIP: Explain the terminology used below. 
Some mushrooms form inside a structure known as a "universal veil", a little bag which covers the entire mushroom and tears open as it grows. The universal veil is important in identification. Remnants of the base of the universal veil (known as the volval bag) are present in some species. Remnants of the top of the veil may remain as rough spots on the top of the cap, possibly a different colour (as in the culturally iconic white-spotted red mushroom, A. muscaria).
===Genus Amanita===
Amanita spp. covers a number of edible mushrooms, as well as some of the most toxic known fungi. The ''Death Cap'' alone is responsible for more than 90% of mushroom-related deaths on Earth. Notable members of the genus include:
====''Amanita phalloides''====
Common name: Death Cap. 
Deadly toxic to the liver and kidneys. (Lethal dose about 30g for adult humans<ref name=Branch>M. Branch -- ''First field guide to mushrooms of Southern Africa'' 2001. Struik Nature. ISBN 978-1-86872-605-9. pp. 12-15.</ref>.) Symptoms of poisoning include vomiting, diarrhoea, thirst and severe abdominal pain<ref name=Branch /><ref name=Jordan>P. Jordan -- ''The mushroom guide and identifier''. 2010. Hermes House. ISBN 978-1-84038-574-8. pp. 100-113.</ref>. Symptoms will appear between 6 and 24 hours after ingestion<ref name=Branch />. If Amanita poisoning is not identified, the victim may appear to recover and die several days later from liver and/or kidney failure. Treatment includes carbon column dialysis, saline cathartic, repeated doses of activated [[charcoal]] and blood transfusions<ref name=Branch /><ref name=Jordan />. Fatal more often than not<ref name=Branch />. 
Identifying features<ref name=Branch /><ref name=Jordan />: Like all ''Amanitas'', the Death Cap has a white spore print and forms inside a universal veil. The cap is smooth and flattens with age, growing to a maximum of about 15cm across. The ring is persistent, white and membranous. The gills are white, free and crowded. Pronounced volval bag. The flesh is white with a faint yellow tinge and the cap appears a slightly yellowish, greenish or smoky-olive white. ''A. phalloides var. alba'' is especially notable in that this rarer almost pure-white variety can be easily misidentified. The smell is described as "sickly sweet" to "foetid" and it is reported to have a pleasant taste.
====''Amanita citrina''====
Common name: False Death Cap. 
To do.
====''Amanita pantherina''====
Common name: Panther Cap. 
Highly toxic. 
To do.

====''Amanita rubescens''====
Common name: Blusher. 
Edible when cooked. Toxic otherwise. 
Description: To do. 
Similar species: Non-experts may easily confuse ''A. rubescens'' with ''A. pantherina''. To do: describe differences.

====''Amanita virosa''====
Common name: Destroying Angel. 
Deadly toxic. 
To do.
====''Amanita muscaria''====
Commonly known as Fly Amanita or Fly Agaric. 
Edible if correctly prepared<ref name=RubelArora>W. Rubel & D. Arora -- ''A study of cultural bias in field guide determinations of mushroom edibility using the iconic mushroom, Amanita muscaria, as an example''. 2008. Economic Botany vol. 62 no. 3. pp. 223-243. Available [http://mushroomhunter.net/muscaria_revised.pdf here] and [http://www.scribd.com/doc/83723731/Muscaria-Revised here].</ref>, despite the fact that field guides usually<ref name=Branch /><ref name=Jordan /> (incorretly) list it as inedible. Detoxification involves boiling out the water-soluble toxins in water and either vinegar or salt, discarding the water<ref name=RubelArora />. If not detoxified, A. muscaria is hallucinogenic and causes euphoria similar to alcohol intoxification<ref name=Jordan />. Relatively few fatalities have been recorded over several centuries and the lethal dose is not exactly known. The historical evidence collected by Rubel and Arora<ref name=RubelArora /> suggests an adult lethal dose somewhere in the vicinity of 12-20 untreated mushrooms. Symptoms may persist for several days in the most extreme cases<ref name=Jordan /> 
Trivia: ''A. muscaria'' was used for centuries to kill flies. After the crushed mushrooms have been mixed with milk, flies drinking the milk will become so intoxicated that they drown<ref name=Branch /><ref name=RubelArora />. The Sami of Lapland sometimes scatter dried A. muscaria for their reindeer, as the intoxicating effect makes them easier to round up<ref name=Jordan />.
====''Amanita jacksonii''====
To do.

==References==
<references />
[[Category:Food]]
[[Category:Biospherics]]

Polymer

2013-06-05T15:58:16Z

ChristiaanK: Remove "to do"

{{stub}}
A '''polymer''' is a kind of complex molecule. Each polymer is made up of one or more simple molecules which are linked into a complex, possibly repeating structure. It may linear or branched.

==Polysaccharides==
[[File:Glucose_explanation.png|frame|Left: a chain of carbon as in glucose, with an oxygen attached to the anomeric carbon. Top right: the structure is rolled into a pyranose ring. Bottom right: The tail structure sits next to a hydrogen atom, on opposite sides of the plane of the pyranose ring. This is alpha-glucose as the hydroxyl group attached to the anomeric carbon is on the "down" side of the ring. Other hydrogen atoms and hydroxyl groups have been omitted for clarity.]]
'''Polysaccharides''' polymers of [[sugar|sugars]]. For example, [[cellulose]] is a common polymer in plants (often just called "fibre" by the food industry). Plants create cellulose by reacting glucose molecules with one another to link them into a long chain. 
In the simplest case where two sugar molecules are linked together, this is called a disaccharide. For example, common table sugar (sucrose) is a disaccharide made of one glucose and one fructose molecule linked together, while maltose is a disaccharide made of two glucose molecules linked together. 
Polysaccharides can be described in terms of which sugars they are made from, how adjacent sugars are oriented relative to one another and which of their carbon atoms take part in the link. Before we go into detail, remember that each sugar is made up of a chain of carbon atoms, one end of it (the so-called anomeric carbon) attached to an oxygen atom which is also attached elsewhere on the chain to form a ring-with-tail structure. Each of the carbon atoms then have hydrogen atoms or hydroxyl-groups attached to its remaining bonds (one of each in most cases)<ref name=Smith>J.G. Smith - ''Organic chemistry'' Int'l ed. 2011. McGraw-Hill. ISBN 978-007-108186-3. pp. 1028-1029, 1056.</ref>. 
In essence, a link is an alpha-link if the OH-group next to the oxygen in the ring (the one attached to the anomeric carbon) is on the opposite side of the ring's plane from the "tail" of the sugar, while it is a beta-link if on the same side<ref name=Wolfe>S.L. Wolfe - ''Molecular and cellular biology'' 1993. Wadsworth. ISBN 0-534-12408-9. p. 52.</ref>. The carbon atoms in a monosaccharide are numbered from 1 for the anomeric carbon and continuing along the chain, so cellulose can be denoted as a chain of glucose with <math>\beta ( 1 \rightarrow 4 )</math> links. All "glycosidic" links (the links that make up disaccharides and polysaccharides) connect an anomeric carbon of one monosaccharide to a different carbon of another or the same kind of monosaccharide<ref name=Smith/>.
==References==
<references />
[[Category:Chemistry]]

Polymer

2013-06-05T15:56:28Z

ChristiaanK: Add image

{{stub}}
A '''polymer''' is a kind of complex molecule. Each polymer is made up of one or more simple molecules which are linked into a complex, possibly repeating structure. It may linear or branched.

==Polysaccharides==
[[File:Glucose_explanation.png|frame|Left: a chain of carbon as in glucose, with an oxygen attached to the anomeric carbon. Top right: the structure is rolled into a pyranose ring. Bottom right: The tail structure sits next to a hydrogen atom, on opposite sides of the plane of the pyranose ring. This is alpha-glucose as the hydroxyl group attached to the anomeric carbon is on the "down" side of the ring. Other hydrogen atoms and hydroxyl groups have been omitted for clarity.]]
'''Polysaccharides''' polymers of [[sugar|sugars]]. For example, [[cellulose]] is a common polymer in plants (often just called "fibre" by the food industry). Plants create cellulose by reacting glucose molecules with one another to link them into a long chain. 
In the simplest case where two sugar molecules are linked together, this is called a disaccharide. For example, common table sugar (sucrose) is a disaccharide made of one glucose and one fructose molecule linked together, while maltose is a disaccharide made of two glucose molecules linked together. 
Polysaccharides can be described in terms of which sugars they are made from, how adjacent sugars are oriented relative to one another and which of their carbon atoms take part in the link. Before we go into detail, remember that each sugar is made up of a chain of carbon atoms, one end of it (the so-called anomeric carbon) attached to an oxygen atom which is also attached elsewhere on the chain to form a ring-with-tail structure. Each of the carbon atoms then have hydrogen atoms or hydroxyl-groups attached to its remaining bonds (one of each in most cases)<ref name=Smith>J.G. Smith - ''Organic chemistry'' Int'l ed. 2011. McGraw-Hill. ISBN 978-007-108186-3. pp. 1028-1029, 1056.</ref>. 
In essence, a link is an alpha-link if the OH-group next to the oxygen in the ring (the one attached to the anomeric carbon) is on the opposite side of the ring's plane from the "tail" of the sugar, while it is a beta-link if on the same side<ref name=Wolfe>S.L. Wolfe - ''Molecular and cellular biology'' 1993. Wadsworth. ISBN 0-534-12408-9. p. 52.</ref>. (To do: I will add an illustration. It is difficult to understand otherwise.) The carbon atoms in a monosaccharide are numbered from 1 for the anomeric carbon and continuing along the chain, so cellulose can be denoted as a chain of glucose with <math>\beta ( 1 \rightarrow 4 )</math> links. All "glycosidic" links (the links that make up disaccharides and polysaccharides) connect an anomeric carbon of one monosaccharide to a different carbon of another or the same kind of monosaccharide<ref name=Smith/>.

==References==
<references />
[[Category:Chemistry]]

Carbon

2013-06-04T18:58:02Z

ChristiaanK: Not true as stated.

{{element
|float=right
|elementName=Carbon
|elementSymbol=C
|protons=6
|abundance=32% ([[atmosphere]] as [[Carbon dioxide|CO2]] and [[Carbon monoxide|CO]])
}}

'''Carbon''' is a nonmetallic element. carbon on Mars is abundant in the the form of [[carbon dioxide]]. Elemental carbon can be produced via the [[bosch reaction]]. One of the important uses of carbon in a colony would be in the production of [[plastics]] and [[hydrocarbons]]. 
Carbon makes up about 0.39%<ref name=Phillips /> of the matter in the solar system.

==Origin==
Massive stars (more than about half a solar mass) are capable of burning helium in the so-called triple-alpha process: 
<math>{}^4 He + {}^4 He \rightleftharpoons {}^8 Be </math> 
<math>{}^4 He + {}^8 Be \rightleftharpoons {}^{12} C^\star</math> 
<math>{}^{12} C^\star \rightarrow {}^{12} C + 2\gamma</math> or <math>{}^{12} C^\star \rightarrow {}^{12} C + e^{+} + e^{-}</math> 
In brief, two helium-4 nuclei are fused to create highly unstable beryllium-8 nuclei. While most of these nuclei simply decay back to helium, a small fraction will fuse with another helium-4 nucleus to form yet another unstable nucleus, an excited state of carbon-12 (here denoted <math>{}^{12}C^\star</math>). While once again most of these nuclei will simply decay back to helium-4 and beryllium-8, a tiny fraction will instead randomly decay to the ground state of carbon-12, where they will remain. Over time, this process produces a lot of energy and carbon.<ref name=Phillips>A.C. Phillips - ''The physics of stars'' 2nd ed. 1999. Wiley. ISBN 0-471-98798-0. pp. 127-135.</ref> 
==Role of carbon-formation in the future of Mars==
Our sun, while massive enough to fuse helium, has not yet begun this process. When the helium core ignites in the distant future, the core will become very hot and dense, causing the outer layers of the sun to expand and cool<ref name=Phillips/>. This "red giant" phase of the sun's life will almost certainly destroy all life on Earth<ref name=RybickiDenis> K.R. Rybicki & C. Denis - ''On the Final Destiny of the Earth and the Solar System'' 2001. Icarus, Vol. 151(1) pp. 130–137. Abstract available [http://www.sciencedirect.com/science/article/pii/S0019103501965911 here].</ref><ref name=SchröderSmith>K.-P. Schröder & R.C. Smith - ''Distant future of the Sun and Earth revisited'' 2008. Monthly Notices of the Royal Astronomical Society, Vol. 386(1) pp. 155–163. Abstract available [http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2966.2008.13022.x/abstract;jsessionid=4AB9DD7C567EA056FE9B3BE775B7E346.d01t03?deniedAccessCustomisedMessage=&userIsAuthenticated=false here].</ref>, quite possibly evaporating the planet, but Mars is likely to survive<ref name=RybickiDenis />. Whether conditions on Mars would be tolerable for any Earth-origin lifeforms at that time depends on less accurately known aspects of the process, mainly how much mass the sun loses and how much drag the planet experiences, but it seems likely<ref name=LopezSchneiderDanchi>B. Lopez, J. Schneider & W.C. Danchi - '' Can Life Develop in the Expanded Habitable Zones around Red Giant Stars? '' 2005. The Astrophysical Journal, Vol. 627(2). Full text [http://iopscience.iop.org/0004-637X/627/2/974 here].</ref> that the planet will be reasonably tolerable for hundreds of millions, if not billions of years.

==Abundance==
Because there are no stable atomic nuclei of mass numbers 5 and 8, the triple-alpha process is the only way in which stars can create elements beyond helium on a large scale<ref name=Phillips />. As a result, carbon is the fourth most common element in the universe. (It lies after oxygen because the same stars that create carbon-12 mostly convert it into oxygen-16 by the addition of another helium-4 nucleus<ref name=Phillips />.)

==Organic Chemistry==
Carbon is an essential element in [[organic chemistry|organic molecules]].

==See Also==

*[[Hydrocarbon synthesis]]

*[[In-situ resource utilization]]

==References==
<references />

[[category:elements]]

Carbon

2013-06-04T18:55:58Z

ChristiaanK: /* Role of carbon-formation in the future of Mars */

{{element
|float=right
|elementName=Carbon
|elementSymbol=C
|protons=6
|abundance=32% ([[atmosphere]] as [[Carbon dioxide|CO2]] and [[Carbon monoxide|CO]])
}}

'''Carbon''' is a nonmetallic element. carbon on Mars is abundant in the the form of [[carbon dioxide]]. Elemental carbon can be produced via the [[bosch reaction]]. However, elemental carbon will be of little use to a colony, where its most important use will be in the production of [[plastics]] and [[hydrocarbons]]. 
Carbon makes up about 0.39%<ref name=Phillips /> of the matter in the solar system.

==Origin==
Massive stars (more than about half a solar mass) are capable of burning helium in the so-called triple-alpha process: 
<math>{}^4 He + {}^4 He \rightleftharpoons {}^8 Be </math> 
<math>{}^4 He + {}^8 Be \rightleftharpoons {}^{12} C^\star</math> 
<math>{}^{12} C^\star \rightarrow {}^{12} C + 2\gamma</math> or <math>{}^{12} C^\star \rightarrow {}^{12} C + e^{+} + e^{-}</math> 
In brief, two helium-4 nuclei are fused to create highly unstable beryllium-8 nuclei. While most of these nuclei simply decay back to helium, a small fraction will fuse with another helium-4 nucleus to form yet another unstable nucleus, an excited state of carbon-12 (here denoted <math>{}^{12}C^\star</math>). While once again most of these nuclei will simply decay back to helium-4 and beryllium-8, a tiny fraction will instead randomly decay to the ground state of carbon-12, where they will remain. Over time, this process produces a lot of energy and carbon.<ref name=Phillips>A.C. Phillips - ''The physics of stars'' 2nd ed. 1999. Wiley. ISBN 0-471-98798-0. pp. 127-135.</ref> 
==Role of carbon-formation in the future of Mars==
Our sun, while massive enough to fuse helium, has not yet begun this process. When the helium core ignites in the distant future, the core will become very hot and dense, causing the outer layers of the sun to expand and cool<ref name=Phillips/>. This "red giant" phase of the sun's life will almost certainly destroy all life on Earth<ref name=RybickiDenis> K.R. Rybicki & C. Denis - ''On the Final Destiny of the Earth and the Solar System'' 2001. Icarus, Vol. 151(1) pp. 130–137. Abstract available [http://www.sciencedirect.com/science/article/pii/S0019103501965911 here].</ref><ref name=SchröderSmith>K.-P. Schröder & R.C. Smith - ''Distant future of the Sun and Earth revisited'' 2008. Monthly Notices of the Royal Astronomical Society, Vol. 386(1) pp. 155–163. Abstract available [http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2966.2008.13022.x/abstract;jsessionid=4AB9DD7C567EA056FE9B3BE775B7E346.d01t03?deniedAccessCustomisedMessage=&userIsAuthenticated=false here].</ref>, quite possibly evaporating the planet, but Mars is likely to survive<ref name=RybickiDenis />. Whether conditions on Mars would be tolerable for any Earth-origin lifeforms at that time depends on less accurately known aspects of the process, mainly how much mass the sun loses and how much drag the planet experiences, but it seems likely<ref name=LopezSchneiderDanchi>B. Lopez, J. Schneider & W.C. Danchi - '' Can Life Develop in the Expanded Habitable Zones around Red Giant Stars? '' 2005. The Astrophysical Journal, Vol. 627(2). Full text [http://iopscience.iop.org/0004-637X/627/2/974 here].</ref> that the planet will be reasonably tolerable for hundreds of millions, if not billions of years.

==Abundance==
Because there are no stable atomic nuclei of mass numbers 5 and 8, the triple-alpha process is the only way in which stars can create elements beyond helium on a large scale<ref name=Phillips />. As a result, carbon is the fourth most common element in the universe. (It lies after oxygen because the same stars that create carbon-12 mostly convert it into oxygen-16 by the addition of another helium-4 nucleus<ref name=Phillips />.)

==Organic Chemistry==
Carbon is an essential element in [[organic chemistry|organic molecules]].

==See Also==

*[[Hydrocarbon synthesis]]

*[[In-situ resource utilization]]

==References==
<references />

[[category:elements]]

Carbon

2013-06-04T18:55:27Z

ChristiaanK: Expanded

{{element
|float=right
|elementName=Carbon
|elementSymbol=C
|protons=6
|abundance=32% ([[atmosphere]] as [[Carbon dioxide|CO2]] and [[Carbon monoxide|CO]])
}}

'''Carbon''' is a nonmetallic element. carbon on Mars is abundant in the the form of [[carbon dioxide]]. Elemental carbon can be produced via the [[bosch reaction]]. However, elemental carbon will be of little use to a colony, where its most important use will be in the production of [[plastics]] and [[hydrocarbons]]. 
Carbon makes up about 0.39%<ref name=Phillips /> of the matter in the solar system.

==Origin==
Massive stars (more than about half a solar mass) are capable of burning helium in the so-called triple-alpha process: 
<math>{}^4 He + {}^4 He \rightleftharpoons {}^8 Be </math> 
<math>{}^4 He + {}^8 Be \rightleftharpoons {}^{12} C^\star</math> 
<math>{}^{12} C^\star \rightarrow {}^{12} C + 2\gamma</math> or <math>{}^{12} C^\star \rightarrow {}^{12} C + e^{+} + e^{-}</math> 
In brief, two helium-4 nuclei are fused to create highly unstable beryllium-8 nuclei. While most of these nuclei simply decay back to helium, a small fraction will fuse with another helium-4 nucleus to form yet another unstable nucleus, an excited state of carbon-12 (here denoted <math>{}^{12}C^\star</math>). While once again most of these nuclei will simply decay back to helium-4 and beryllium-8, a tiny fraction will instead randomly decay to the ground state of carbon-12, where they will remain. Over time, this process produces a lot of energy and carbon.<ref name=Phillips>A.C. Phillips - ''The physics of stars'' 2nd ed. 1999. Wiley. ISBN 0-471-98798-0. pp. 127-135.</ref> 
==Role of carbon-formation in the future of Mars==
Our sun, while massive enough to fuse helium, has not yet begun this process. When helium the helium core ignites in the distant future, the core will become very hot and dense, causing the outer layers of the sun to expand and cool<ref name=Phillips/>. This "red giant" phase of the sun's life will almost certainly destroy all life on Earth<ref name=RybickiDenis> K.R. Rybicki & C. Denis - ''On the Final Destiny of the Earth and the Solar System'' 2001. Icarus, Vol. 151(1) pp. 130–137. Abstract available [http://www.sciencedirect.com/science/article/pii/S0019103501965911 here].</ref><ref name=SchröderSmith>K.-P. Schröder & R.C. Smith - ''Distant future of the Sun and Earth revisited'' 2008. Monthly Notices of the Royal Astronomical Society, Vol. 386(1) pp. 155–163. Abstract available [http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2966.2008.13022.x/abstract;jsessionid=4AB9DD7C567EA056FE9B3BE775B7E346.d01t03?deniedAccessCustomisedMessage=&userIsAuthenticated=false here].</ref>, quite possibly evaporating the planet, but Mars is likely to survive<ref name=RybickiDenis />. Whether conditions on Mars would be tolerable for any Earth-origin lifeforms at that time depends on less accurately known aspects of the process, mainly how much mass the sun loses and how much drag the planet experiences, but it seems likely<ref name=LopezSchneiderDanchi>B. Lopez, J. Schneider & W.C. Danchi - '' Can Life Develop in the Expanded Habitable Zones around Red Giant Stars? '' 2005. The Astrophysical Journal, Vol. 627(2). Full text [http://iopscience.iop.org/0004-637X/627/2/974 here].</ref> that the planet will be reasonably tolerable for hundreds of millions, if not billions of years.

==Abundance==
Because there are no stable atomic nuclei of mass numbers 5 and 8, the triple-alpha process is the only way in which stars can create elements beyond helium on a large scale<ref name=Phillips />. As a result, carbon is the fourth most common element in the universe. (It lies after oxygen because the same stars that create carbon-12 mostly convert it into oxygen-16 by the addition of another helium-4 nucleus<ref name=Phillips />.)

==Organic Chemistry==
Carbon is an essential element in [[organic chemistry|organic molecules]].

==See Also==

*[[Hydrocarbon synthesis]]

*[[In-situ resource utilization]]

==References==
<references />

[[category:elements]]

File:Glucose explanation.png

2013-06-04T17:15:33Z

ChristiaanK: This image illustrates how the structure of cyclical monosaccharides can be distinguised. Left: The length of this monosaccharide is 6 carbon atoms. The anomeric carbon is at the top, just below the oxygen. Top right: It is rolled into a pyranose ring (5

This image illustrates how the structure of cyclical monosaccharides can be distinguised.
Left: The length of this monosaccharide is 6 carbon atoms. The anomeric carbon is at the top, just below the oxygen.
Top right: It is rolled into a pyranose ring (5 carbons + oxygen), the only alternative is a furanose ring (4 carbons + oxygen). The anomeric carbon is on the right.
Bottom right: The "tail" (which would be CH2OH in this case) is defined to be on the "upper" side of the ring's plane and the hydrogen adjacent to it on the "bottom". In this case, the anomeric carbon has an "upper" hydrogen atom and a "lower" hydroxyl group.

Image created with Avogadro and Gimp.

Polymer

2013-06-04T17:06:18Z

ChristiaanK: Typo

{{stub}}
A '''polymer''' is a kind of complex molecule. Each polymer is made up of one or more simple molecules which are linked into a complex, possibly repeating structure. It may linear or branched.

==Polysaccharides==
'''Polysaccharides''' polymers of [[sugar|sugars]]. For example, [[cellulose]] is a common polymer in plants (often just called "fibre" by the food industry). Plants create cellulose by reacting glucose molecules with one another to link them into a long chain. 
In the simplest case where two sugar molecules are linked together, this is called a disaccharide. For example, common table sugar (sucrose) is a disaccharide made of one glucose and one fructose molecule linked together, while maltose is a disaccharide made of two glucose molecules linked together. 
Polysaccharides can be described in terms of which sugars they are made from, how adjacent sugars are oriented relative to one another and which of their carbon atoms take part in the link. Before we go into detail, remember that each sugar is made up of a chain of carbon atoms, one end of it (the so-called anomeric carbon) attached to an oxygen atom which is also attached elsewhere on the chain to form a ring-with-tail structure. Each of the carbon atoms then have hydrogen atoms or hydroxyl-groups attached to its remaining bonds (one of each in most cases)<ref name=Smith>J.G. Smith - ''Organic chemistry'' Int'l ed. 2011. McGraw-Hill. ISBN 978-007-108186-3. pp. 1028-1029, 1056.</ref>. 
In essence, a link is an alpha-link if the OH-group next to the oxygen in the ring (the one attached to the anomeric carbon) is on the opposite side of the ring's plane from the "tail" of the sugar, while it is a beta-link if on the same side<ref name=Wolfe>S.L. Wolfe - ''Molecular and cellular biology'' 1993. Wadsworth. ISBN 0-534-12408-9. p. 52.</ref>. (To do: I will add an illustration. It is difficult to understand otherwise.) The carbon atoms in a monosaccharide are numbered from 1 for the anomeric carbon and continuing along the chain, so cellulose can be denoted as a chain of glucose with <math>\beta ( 1 \rightarrow 4 )</math> links. All "glycosidic" links (the links that make up disaccharides and polysaccharides) connect an anomeric carbon of one monosaccharide to a different carbon of another or the same kind of monosaccharide<ref name=Smith/>.

==References==
<references />
[[Category:Chemistry]]

Polymer

2013-06-04T16:49:47Z

ChristiaanK: Remove ambiguity

{{stub}}
A '''polymer''' is a kind of complex molecule. Each polymer is made up of one or more simple molecules which are linked into a complex, possibly repeating structure. It may linear or branched.

==Polysaccharides==
'''Polysaccharides''' polymers of [[sugar|sugars]]. For example, [[cellulose]] is a common polymer in plants (often just called "fibre" by the food industry). Plants create cellulose by reacting glucose molecules with one another to link them into a long chain. 
In the simplest case where two sugar molecules are linked together, this is called a disaccharide. For example, common table sugar (sucrose) is a disaccharide made of one glucose and one fructose molecule linked together, while maltose is a disaccharide made of two glucose molecules linked together. 
Polysaccharides can be described in terms of which sugars they are made from, how adjacent sugars are oriented relative to one another and which of their carbon atoms take part in the link. Before we go into detail, remember that each sugar is made up of a chain of carbon atoms, one end of it (the so-called anomeric carbon) attached to an oxygen atom which is also attached elsewhere on the chain to form a ring-with-tail structure. Each of the carbon atoms then have hydrogen atoms or hydroxy-groups attached to its remaining bonds (one of each in most cases)<ref name=Smith>J.G. Smith - ''Organic chemistry'' Int'l ed. 2011. McGraw-Hill. ISBN 978-007-108186-3. pp. 1028-1029, 1056.</ref>. 
In essence, a link is an alpha-link if the OH-group next to the oxygen in the ring (the one attached to the anomeric carbon) is on the opposite side of the ring's plane from the "tail" of the sugar, while it is a beta-link if on the same side<ref name=Wolfe>S.L. Wolfe - ''Molecular and cellular biology'' 1993. Wadsworth. ISBN 0-534-12408-9. p. 52.</ref>. (To do: I will add an illustration. It is difficult to understand otherwise.) The carbon atoms in a monosaccharide are numbered from 1 for the anomeric carbon and continuing along the chain, so cellulose can be denoted as a chain of glucose with <math>\beta ( 1 \rightarrow 4 )</math> links. All "glycosidic" links (the links that make up disaccharides and polysaccharides) connect an anomeric carbon of one monosaccharide to a different carbon of another or the same kind of monosaccharide<ref name=Smith/>.

==References==
<references />
[[Category:Chemistry]]

Natural fiber

2013-06-03T19:02:11Z

ChristiaanK: Drive nail in coffin of that idea :)

Most [[plants]] and [[animals]] produce '''natural fibers'''. This article deals mainly with those fibers that are useful for Martian [[settlement]]. [[Synthetic fiber]] has succeeded natural fiber in many applications on [[Earth]], but it requires a larger industrial base than will likely be available to initial settlements. Moreover, most synthetic fibres are made from crude oil, which is unlikely to exist on Mars in the first place.

==Plant Fibers==
Plant fibers are likely the first to be produced in any settlement. Though they often involve post-processing, overall they require less resource and time investment than animal fiber.
===Cotton===
The [[cotton]] plant produces white fibers which surround its [[seeds]]. These seeds must be removed before the cotton can be processed. Cotton is commonly used in [[textiles]] and fine [[paper]]. Wet cotton clothing looses much of its [[insulation|insulating]] properties. 
Once the seeds have been removed, cotton is almost completely pure [[cellulose]]<ref name=Smith>J.G. Smith - ''Organic chemistry'' Int'l ed. 2011. McGraw-Hill. ISBN 978-007-108186-3. p. 1059.</ref>

===Linen===
[[Linen]] is obtained from the processed stocks of the [[flax]] plant. It is used in [[clothing]] and bedding.
===Hemp===
[[Hemp]] is a strong fiber obtained from the plant of the same name. It was commonly used in ropes and rigging. Hemp bridges still span canyons and rivers in some regions on Earth. It has been replaced by [[synthetic fiber]] in many applications.
===Bamboo===
The fibers of [[bamboo]], once chemically processed, become soft and easily woven into textiles. The chemical treatment needed may restrict bamboo to [[food]] and structural applications.

==Animal Fibers==
The production of animal fibers is more resource intensive than that of plant fibers. The animals take up space and resources, and require constant care by residents.
===Silk===
[[Silk]] is produced by the [[silkworm]] as it spins its cocoon. Silkworms feed on [[mulberry]] leaves, and may be impractical for small settlements.
===Spider Silk===
[[Spiders]] produce silk for shelter, support, and the capture of prey. So far, efforts to produce commercially viable quantities of [[spider silk]] have failed.
===Wool===
[[Wool]] is the long, flexible hair of [[mammals]] such as [[goats]], [[alpacas]] and [[sheep]]. It is a better thermal insulator than cotton or linen, and retains much of its insulation value even when wet. Certain wools are rough and can cause skin irritation.
===Hair===
Many types of [[hair]] are unfit for use as wool. These hairs are used as bristles in brushes and brooms. When still attached to the hide they can be fashioned into fir clothing.
===Sinew===
The ligaments of animals contain large amounts of the natural [[polymer]] [[collagen]]. Sinew is durable (for a natural fiber), and is used as thread and cordage.

==References==
<references />
[[category:material]]

Natural fiber

2013-06-03T19:00:06Z

ChristiaanK: References section

Most [[plants]] and [[animals]] produce '''natural fibers'''. This article deals mainly with those fibers that are useful for Martian [[settlement]]. [[Synthetic fiber]] has succeeded natural fiber in many applications on [[Earth]], but it requires a larger industrial base than will likely be available to initial settlements.

==Plant Fibers==
Plant fibers are likely the first to be produced in any settlement. Though they often involve post-processing, overall they require less resource and time investment than animal fiber.
===Cotton===
The [[cotton]] plant produces white fibers which surround its [[seeds]]. These seeds must be removed before the cotton can be processed. Cotton is commonly used in [[textiles]] and fine [[paper]]. Wet cotton clothing looses much of its [[insulation|insulating]] properties. 
Once the seeds have been removed, cotton is almost completely pure [[cellulose]]<ref name=Smith>J.G. Smith - ''Organic chemistry'' Int'l ed. 2011. McGraw-Hill. ISBN 978-007-108186-3. p. 1059.</ref>

===Linen===
[[Linen]] is obtained from the processed stocks of the [[flax]] plant. It is used in [[clothing]] and bedding.
===Hemp===
[[Hemp]] is a strong fiber obtained from the plant of the same name. It was commonly used in ropes and rigging. Hemp bridges still span canyons and rivers in some regions on Earth. It has been replaced by [[synthetic fiber]] in many applications.
===Bamboo===
The fibers of [[bamboo]], once chemically processed, become soft and easily woven into textiles. The chemical treatment needed may restrict bamboo to [[food]] and structural applications.

==Animal Fibers==
The production of animal fibers is more resource intensive than that of plant fibers. The animals take up space and resources, and require constant care by residents.
===Silk===
[[Silk]] is produced by the [[silkworm]] as it spins its cocoon. Silkworms feed on [[mulberry]] leaves, and may be impractical for small settlements.
===Spider Silk===
[[Spiders]] produce silk for shelter, support, and the capture of prey. So far, efforts to produce commercially viable quantities of [[spider silk]] have failed.
===Wool===
[[Wool]] is the long, flexible hair of [[mammals]] such as [[goats]], [[alpacas]] and [[sheep]]. It is a better thermal insulator than cotton or linen, and retains much of its insulation value even when wet. Certain wools are rough and can cause skin irritation.
===Hair===
Many types of [[hair]] are unfit for use as wool. These hairs are used as bristles in brushes and brooms. When still attached to the hide they can be fashioned into fir clothing.
===Sinew===
The ligaments of animals contain large amounts of the natural [[polymer]] [[collagen]]. Sinew is durable (for a natural fiber), and is used as thread and cordage.

==References==
<references />
[[category:material]]

Natural fiber

2013-06-03T18:59:34Z

ChristiaanK: /* Cotton */

Most [[plants]] and [[animals]] produce '''natural fibers'''. This article deals mainly with those fibers that are useful for Martian [[settlement]]. [[Synthetic fiber]] has succeeded natural fiber in many applications on [[Earth]], but it requires a larger industrial base than will likely be available to initial settlements.

==Plant Fibers==
Plant fibers are likely the first to be produced in any settlement. Though they often involve post-processing, overall they require less resource and time investment than animal fiber.
===Cotton===
The [[cotton]] plant produces white fibers which surround its [[seeds]]. These seeds must be removed before the cotton can be processed. Cotton is commonly used in [[textiles]] and fine [[paper]]. Wet cotton clothing looses much of its [[insulation|insulating]] properties. 
Once the seeds have been removed, cotton is almost completely pure [[cellulose]]<ref name=Smith>J.G. Smith - ''Organic chemistry'' Int'l ed. 2011. McGraw-Hill. ISBN 978-007-108186-3. p. 1059.</ref>

===Linen===
[[Linen]] is obtained from the processed stocks of the [[flax]] plant. It is used in [[clothing]] and bedding.
===Hemp===
[[Hemp]] is a strong fiber obtained from the plant of the same name. It was commonly used in ropes and rigging. Hemp bridges still span canyons and rivers in some regions on Earth. It has been replaced by [[synthetic fiber]] in many applications.
===Bamboo===
The fibers of [[bamboo]], once chemically processed, become soft and easily woven into textiles. The chemical treatment needed may restrict bamboo to [[food]] and structural applications.

==Animal Fibers==
The production of animal fibers is more resource intensive than that of plant fibers. The animals take up space and resources, and require constant care by residents.
===Silk===
[[Silk]] is produced by the [[silkworm]] as it spins its cocoon. Silkworms feed on [[mulberry]] leaves, and may be impractical for small settlements.
===Spider Silk===
[[Spiders]] produce silk for shelter, support, and the capture of prey. So far, efforts to produce commercially viable quantities of [[spider silk]] have failed.
===Wool===
[[Wool]] is the long, flexible hair of [[mammals]] such as [[goats]], [[alpacas]] and [[sheep]]. It is a better thermal insulator than cotton or linen, and retains much of its insulation value even when wet. Certain wools are rough and can cause skin irritation.
===Hair===
Many types of [[hair]] are unfit for use as wool. These hairs are used as bristles in brushes and brooms. When still attached to the hide they can be fashioned into fir clothing.
===Sinew===
The ligaments of animals contain large amounts of the natural [[polymer]] [[collagen]]. Sinew is durable (for a natural fiber), and is used as thread and cordage.

[[category:material]]

Polymer

2013-06-03T18:52:09Z

ChristiaanK: A little easier to follow

{{stub}}
A '''polymer''' is a kind of complex molecule. Each polymer is made up of one or more simple molecules which are linked into a complex, possibly repeating structure. It may linear or branched.

==Polysaccharides==
'''Polysaccharides''' polymers of [[sugar|sugars]]. For example, [[cellulose]] is a common polymer in plants (often just called "fibre" by the food industry). Plants create cellulose by reacting glucose molecules with one another to link them into a long chain. 
When only two sugars are linked, this is called a disaccharide. For example, common table sugar (sucrose) is a disaccharide of glucose and fructose. 
Polysaccharides can be described in terms of which sugars they are made from, how adjacent sugars are oriented relative to one another and which of their carbon atoms take part in the link. Before we go into detail, remember that each sugar is made up of a chain of carbon atoms, one end of it (the so-called anomeric carbon) attached to an oxygen atom which is also attached elsewhere on the chain to form a ring-with-tail structure. Each of the carbon atoms then have hydrogen atoms or hydroxy-groups attached to its remaining bonds (one of each in most cases)<ref name=Smith>J.G. Smith - ''Organic chemistry'' Int'l ed. 2011. McGraw-Hill. ISBN 978-007-108186-3. pp. 1028-1029, 1056.</ref>. 
In essence, a link is an alpha-link if the OH-group next to the oxygen in the ring (the one attached to the anomeric carbon) is on the opposite side of the ring's plane from the "tail" of the sugar, while it is a beta-link if on the same side<ref name=Wolfe>S.L. Wolfe - ''Molecular and cellular biology'' 1993. Wadsworth. ISBN 0-534-12408-9. p. 52.</ref>. (To do: I will add an illustration. It is difficult to understand otherwise.) The carbon atoms in a monosaccharide are numbered from 1 for the anomeric carbon and continuing along the chain, so cellulose can be denoted as a chain of glucose with <math>\beta ( 1 \rightarrow 4 )</math> links. All "glycosidic" links (the links that make up disaccharides and polysaccharides) connect an anomeric carbon of one monosaccharide to a different carbon of another or the same kind of monosaccharide<ref name=Smith/>.

==References==
<references />
[[Category:Chemistry]]

Polymer

2013-06-03T18:50:22Z

ChristiaanK: Fix link

{{stub}}
A '''polymer''' is a kind of complex molecule. Each polymer is made up of one or more simple molecules which are linked into a complex, possibly repeating structure. It may linear or branched.

==Polysaccharides==
'''Polysaccharides''' polymers of [[sugar|sugars]]. For example, [[cellulose]] is a common polymer in plants (often just called "fibre" by the food industry). Plants create cellulose by reacting glucose molecules with one another to link them into a long chain. 
When only two sugars are linked, this is called a disaccharide. For example, common table sugar (sucrose) is a disaccharide of glucose and fructose. 
Polysaccharides can be described in terms of which sugars they are made from, how adjacent sugars are oriented relative to one another and which of their carbon atoms take part in the link. Before we go into detail, remember that each sugar is made up of a chain of carbon atoms, one end of it (the so-called anomeric carbon) attached to an oxygen atom which is also attached elsewhere on the chain to form a ring-with-tail structure. Each of the carbon atoms then have hydrogen atoms or hydroxy-groups attached to its remaining bonds (one of each in most cases)<ref name=Smith>J.G. Smith - ''Organic chemistry'' Int'l ed. 2011. McGraw-Hill. ISBN 978-007-108186-3. pp. 1028-1029, 1056.</ref>. 
In essence, a link is an alpha-link if the OH-group next to the oxygen in the ring (the one attached to the anomeric carbon) is on the opposite side of the ring's plane from the rest of the sugar, while it is a beta-link if on the same side<ref name=Wolfe>S.L. Wolfe - ''Molecular and cellular biology'' 1993. Wadsworth. ISBN 0-534-12408-9. p. 52.</ref>. (To do: I will add an illustration. It is difficult to understand otherwise.) The carbon atoms in a monosaccharide are numbered from 1 for the anomeric carbon and continuing along the chain, so cellulose can be denoted as a chain of glucose with <math>\beta ( 1 \rightarrow 4 )</math> links. All "glycosidic" links (the links that make up disaccharides and polysaccharides) connect an anomeric carbon of one monosaccharide to a different carbon of another or the same kind of monosaccharide<ref name=Smith/>.

==References==
<references />
[[Category:Chemistry]]

Polymer

2013-06-03T18:42:31Z

ChristiaanK: Clarify details

{{stub}}
A '''polymer''' is a kind of complex molecule. Each polymer is made up of one or more simple molecules which are linked into a complex, possibly repeating structure. It may linear or branched.

==Polysaccharides==
'''Polysaccharides''' polymers of [[sugar|sugars]]. For example, [[cellulose]] is a common polymer in plants (often just called "fibre" by the food industry). Plants create cellulose by reacting glucose molecules with one another to link them into a long chain. 
When only two sugars are linked, this is called a disaccharide. For example, common table sugar (sucrose) is a disaccharide of glucose and fructose. 
Polysaccharides can be described in terms of which sugars they are made from, how adjacent sugars are oriented relative to one another and which of their carbon atoms take part in the link. Before we go into detail, remember that each sugar is made up of a chain of carbon atoms, one end of it (the so-called anomeric carbon) attached to an oxygen atom which is also attached elsewhere on the chain to form a ring-with-tail structure. Each of the carbon atoms then have hydrogen atoms or hydroxy-groups attached to its remaining bonds (one of each in most cases)<ref name=Smith>J.G. Smith - ''Organic chemistry'' Int'l ed. 2011. McGraw-Hill. ISBN 978-007-108186-3. pp. 1028-1029, 1056.</ref>. 
In essence, a link is an alpha-link if the OH-group next to the oxygen in the ring (the one attached to the anomeric carbon) is on the opposite side of the ring's plane from the rest of the sugar, while it is a beta-link if on the same side<ref name=Wolfe>S.L. Wolfe - ''Molecular and cellular biology'' 1993. Wadsworth. ISBN 0-534-12408-9. p. 52.</ref>. (To do: I will add an illustration. It is difficult to understand otherwise.) The carbon atoms in a monosaccharide are numbered from 1 for the anomeric carbon and continuing along the chain, so cellulose can be denoted as a chain of glucose with <math>\beta ( 1 \rightarrow 4 )</math> links. All "glycosidic" links (the links that make up disaccharides and polysaccharides) connect an anomeric carbon of one monosaccharide to a different carbon of another or the same kind of monosaccharide<ref name=Smith/>.

==References==
<references />
[Category:Chemistry]

Polysaccharide

2013-06-03T17:43:01Z

ChristiaanK: Redirect

#REDIRECT [[Polymer#Polysaccharides]]

Polysaccharides

2013-06-03T17:42:23Z

ChristiaanK: Redirect

#REDIRECT [[Polymer#Polysaccharides]]

Polymer

2013-06-03T17:41:03Z

ChristiaanK: Created article

{{stub}}
A '''polymer''' is a kind of complex molecule. Each polymer is made up of one or more simple molecules which are linked into a complex, possibly repeating structure.

==Polysaccharides==
'''Polysaccharides''' polymers of sugars. For example, [[cellulose]] is a common polymer in plants (often just called "fibre" by the food industry). Plants create cellulose by reacting glucose molecules with one another to link them into a long chain. 
Polysaccharides can be described in terms of which sugars they are made from, how adjacent sugars are oriented relative to one another and which of their carbon atoms take part in the link. In essence, a link is an alpha-link if the OH-group is on the opposite side of the ring's plane from the rest of the sugar, while it is a beta-link if on the same side<ref name=Wolfe>S.L. Wolfe - ''Molecular and cellular biology'' 1993. Wadsworth. ISBN 0-534-12408-9. p. 52.</ref>. (To do: I will add an illustration. It is difficult to understand otherwise.) The carbon atoms to which an adjacent sugar can bond are numbered, so cellulose can be denoted as a chain of glucose with <math>\beta ( 1 \rightarrow 4 )</math> links.

==References==
<references />
[Category:Chemistry]

Mushroom

2013-06-03T17:18:45Z

ChristiaanK: Redirect

#REDIRECT [[Fungi#Mushrooms]]

Fungus

2013-06-03T17:17:40Z

ChristiaanK: Redirect

#REDIRECT [[Fungi]]

Fungi

2013-06-03T17:07:48Z

ChristiaanK: Oops. Wrong word.

'''Fungi''' are eukaryotic organisms closely related to animals. The study of fungi is known as '''mycology'''.

Some fungi are edible and could be grown for [[food]] in a Martian [[colony]]. Fungi, especially some sorts of mildew, are certainly of great use in the artificial ecosystem of a [[greenhouse]], since they are involved in the [[compost|decaying process]].

Some [[human|people]] have an allergy against the spores of mildew, and patients with depressed [[immune system]] can suffer from a fungus infection. As yet, the development of the human immune system under Martian [[gravity]] and [[house|inhouse]] conditions is unclear.

==Cellular biology==
===Cell wall===
Fungal cells have cell walls which may be composed of several glucose [[polymer|polymers]]. For example, chitin (chains of acetylglucosamine joined by [[polysaccharide|<math>\beta ( 1 \rightarrow 4 )</math> links]]) or, as in yeast, callose (which is a glucose chain which differs from cellulose only in that it uses <math>\beta ( 1 \rightarrow 3 )</math> links where cellulose uses <math>\beta ( 1 \rightarrow 4 )</math> links<ref name=Wolfe>S.L. Wolfe - ''Mollecular and cellular biology'' 1993. Wadsworth. ISBN 0-534-12408-9. pp. 17-18, 288-289, 514-517.</ref>.

===Cytoskeleton===
Like all protozoa, animals and plants, fungi have cytoskeletal structures containing microtubules and microfilaments supporting the cytoplasm inside their cells<ref name=Wolfe />. In some fungi there are also intermediate filaments, though not to the same extent as in animals<ref name=Wolfe />. 
The microtubules can be thought of as analogous to the human skeleton, as they maintain the positions of major organelles within the cell<ref name=Wolfe /> Furthermore, the microfilaments and microtubules are responsible for movement in eukarytic cells. This is achieved when the individual polymers slide across one another to create an overall lengthening or contraction of the structure<ref name=Wolfe />. 
It is worth noting that microgravity affects the cytoskeleton<ref name=Lewis_HughesFulford>M.L. Lewis & M. Hughes-Fulford - ''Cellular responses to spaceflight'' 1997. (In S.E. Churchill, ''ed.'' - ''Fundamentals of space life sciences''. Krieger. ISBN 0-89464-051-8) Vol 1. pp. 21-36.</ref>, so fungi could, in principle, be negatively affected by a journey to Mars. While the matter is of academic interest, fungi would almost certainly be much less harmed by a return to gravity than humans and no mission would therefore be compromised. It is even possible that fungi may grow more readily in microgravity, as some primitive eukaryotes do<ref name=Lewis_HughesFulford />, though that is unlikely as the positive effect is at least mostly due to reduced energy expenditure during movement.
==Mushrooms==
'''Mushrooms''' are the "fruiting bodies" of certain fungi or, more formally, the sporulating organs of certain complex fungi. The word '''toadstool''' is sometimes used in informal conversation to refer to inedible mushrooms. Mushrooms are complete proteins, and their nutritional value are in some respects (such as protein quality) in-between those of plant and animal foods. This makes them a potentially very valuable food source in spaceflight.
 TO DO: Explain the terminology used below.
===Genus Amanita===
Amanita spp. covers a number of edible mushrooms, as well as some of the most toxic known fungi. The ''Death Cap'' alone is responsible for more than 90% of mushroom-related deaths on Earth. Notable members of the genus include:
====''Amanita phalloides''====
Common name: Death Cap. 
Deadly toxic to the liver and kidneys. (Lethal dose about 30g for adult humans<ref name=Branch>M. Branch -- ''First field guide to mushrooms of Southern Africa'' 2001. Struik Nature. ISBN 978-1-86872-605-9. pp. 12-15.</ref>.) Symptoms of poisoning include vomiting, diarrhoea, thirst and severe abdominal pain<ref name=Branch /><ref name=Jordan>P. Jordan -- ''The mushroom guide and identifier''. 2010. Hermes House. ISBN 978-1-84038-574-8. pp. 100-113.</ref>. Symptoms will appear between 6 and 24 hours after ingestion<ref name=Branch />. If Amanita poisoning is not identified, the victim may appear to recover and die several days later from liver and/or kidney failure. Treatment includes carbon column dialysis, saline cathartic, repeated doses of activated [[charcoal]] and blood transfusions<ref name=Branch /><ref name=Jordan />. Fatal more often than not<ref name=Branch />. 
Identifying features<ref name=Branch /><ref name=Jordan />: Like all ''Amanitas'', the Death Cap has a white spore print and forms inside a universal veil. The cap is smooth and flattens with age, growing to a maximum of about 15cm across. The ring is persistent, white and membranous. The gills are white, free and crowded. Pronounced volval bag. The flesh is white with a faint yellow tinge and the cap appears a slightly yellowish, greenish or smoky-olive white. ''A. phalloides var. alba'' is especially notable in that this rarer almost pure-white variety can be easily misidentified. The smell is described as "sickly sweet" to "foetid" and it is reported to have a pleasant taste.
====''Amanita citrina''====
Common name: False Death Cap. 
To do.
====''Amanita pantherina''====
Common name: Panther Cap. 
Highly toxic. 
To do.

====''Amanita rubescens''====
Common name: Blusher. 
Edible when cooked. Toxic otherwise. 
Description: To do. 
Similar species: Non-experts may easily confuse ''A. rubescens'' with ''A. pantherina''. To do: describe differences.

====''Amanita virosa''====
Common name: Destroying Angel. 
Deadly toxic. 
To do.
====''Amanita muscaria''====
Commonly known as Fly Amanita or Fly Agaric. 
Edible if correctly prepared<ref name=RubelArora>W. Rubel & D. Arora -- ''A study of cultural bias in field guide determinations of mushroom edibility using the iconic mushroom, Amanita muscaria, as an example''. 2008. Economic Botany vol. 62 no. 3. pp. 223-243. Available [http://mushroomhunter.net/muscaria_revised.pdf here] and [http://www.scribd.com/doc/83723731/Muscaria-Revised here].</ref>, despite the fact that field guides usually<ref name=Branch /><ref name=Jordan /> (incorretly) list it as inedible. Detoxification involves boiling out the water-soluble toxins in water and either vinegar or salt, discarding the water<ref name=RubelArora />. If not detoxified, A. muscaria is hallucinogenic and causes euphoria similar to alcohol intoxification<ref name=Jordan />. Relatively few fatalities have been recorded over several centuries and the lethal dose is not exactly known. The historical evidence collected by Rubel and Arora<ref name=RubelArora /> suggests an adult lethal dose somewhere in the vicinity of 12-20 untreated mushrooms. Symptoms may persist for several days in the most extreme cases<ref name=Jordan /> 
Trivia: ''A. muscaria'' was used for centuries to kill flies. After the crushed mushrooms have been mixed with milk, flies drinking the milk will become so intoxicated that they drown<ref name=Branch /><ref name=RubelArora />. The Sami of Lapland sometimes scatter dried A. muscaria for their reindeer, as the intoxicating effect makes them easier to round up<ref name=Jordan />.
====''Amanita jacksonii''====
To do.

==References==
<references />
[[Category:Food]]
[[Category:Biospherics]]

Fungi

2013-06-03T17:04:16Z

ChristiaanK: Expanded

'''Fungi''' are eukaryotic organisms closely related to animals. The study of fungi is known as '''mycology'''.

Some fungi are edible and could be grown for [[food]] in a Martian [[colony]]. Fungi, especially some sorts of mildew, are certainly of great use in the artificial ecosystem of a [[greenhouse]], since they are involved in the [[compost|decaying process]].

Some [[human|people]] have an allergy against the spores of mildew, and patients with depressed [[immune system]] can suffer from a fungus infection. As yet, the development of the human immune system under Martian [[gravity]] and [[house|inhouse]] conditions is unclear.

==Cellular biology==
===Cell wall===
Fungal cells have cell walls which may be composed of several glucose [[polymer|polymers]]. For example, chitin (chains of acetylglucosamine joined by [[polysaccharide|<math>\beta ( 1 \rightarrow 4 )</math> links]]) or, as in yeast, callose (which is a glucose chain which differs from cellulose only in that it uses <math>\beta ( 1 \rightarrow 3 )</math> links where glucose uses <math>\beta ( 1 \rightarrow 4 )</math> links<ref name=Wolfe>S.L. Wolfe - ''Mollecular and cellular biology'' 1993. Wadsworth. ISBN 0-534-12408-9. pp. 17-18, 288-289, 514-517.</ref>.
===Cytoskeleton===
Like all protozoa, animals and plants, fungi have cytoskeletal structures containing microtubules and microfilaments supporting the cytoplasm inside their cells<ref name=Wolfe />. In some fungi there are also intermediate filaments, though not to the same extent as in animals<ref name=Wolfe />. 
The microtubules can be thought of as analogous to the human skeleton, as they maintain the positions of major organelles within the cell<ref name=Wolfe /> Furthermore, the microfilaments and microtubules are responsible for movement in eukarytic cells. This is achieved when the individual polymers slide across one another to create an overall lengthening or contraction of the structure<ref name=Wolfe />. 
It is worth noting that microgravity affects the cytoskeleton<ref name=Lewis_HughesFulford>M.L. Lewis & M. Hughes-Fulford - ''Cellular responses to spaceflight'' 1997. (In S.E. Churchill, ''ed.'' - ''Fundamentals of space life sciences''. Krieger. ISBN 0-89464-051-8) Vol 1. pp. 21-36.</ref>, so fungi could, in principle, be negatively affected by a journey to Mars. While the matter is of academic interest, fungi would almost certainly be much less harmed by a return to gravity than humans and no mission would therefore be compromised. It is even possible that fungi may grow more readily in microgravity, as some primitive eukaryotes do<ref name=Lewis_HughesFulford />, though that is unlikely as the positive effect is at least mostly due to reduced energy expenditure during movement.
==Mushrooms==
'''Mushrooms''' are the "fruiting bodies" of certain fungi or, more formally, the sporulating organs of certain complex fungi. The word '''toadstool''' is sometimes used in informal conversation to refer to inedible mushrooms. Mushrooms are complete proteins, and their nutritional value are in some respects (such as protein quality) in-between those of plant and animal foods. This makes them a potentially very valuable food source in spaceflight.
 TO DO: Explain the terminology used below.
===Genus Amanita===
Amanita spp. covers a number of edible mushrooms, as well as some of the most toxic known fungi. The ''Death Cap'' alone is responsible for more than 90% of mushroom-related deaths on Earth. Notable members of the genus include:
====''Amanita phalloides''====
Common name: Death Cap. 
Deadly toxic to the liver and kidneys. (Lethal dose about 30g for adult humans<ref name=Branch>M. Branch -- ''First field guide to mushrooms of Southern Africa'' 2001. Struik Nature. ISBN 978-1-86872-605-9. pp. 12-15.</ref>.) Symptoms of poisoning include vomiting, diarrhoea, thirst and severe abdominal pain<ref name=Branch /><ref name=Jordan>P. Jordan -- ''The mushroom guide and identifier''. 2010. Hermes House. ISBN 978-1-84038-574-8. pp. 100-113.</ref>. Symptoms will appear between 6 and 24 hours after ingestion<ref name=Branch />. If Amanita poisoning is not identified, the victim may appear to recover and die several days later from liver and/or kidney failure. Treatment includes carbon column dialysis, saline cathartic, repeated doses of activated [[charcoal]] and blood transfusions<ref name=Branch /><ref name=Jordan />. Fatal more often than not<ref name=Branch />. 
Identifying features<ref name=Branch /><ref name=Jordan />: Like all ''Amanitas'', the Death Cap has a white spore print and forms inside a universal veil. The cap is smooth and flattens with age, growing to a maximum of about 15cm across. The ring is persistent, white and membranous. The gills are white, free and crowded. Pronounced volval bag. The flesh is white with a faint yellow tinge and the cap appears a slightly yellowish, greenish or smoky-olive white. ''A. phalloides var. alba'' is especially notable in that this rarer almost pure-white variety can be easily misidentified. The smell is described as "sickly sweet" to "foetid" and it is reported to have a pleasant taste.
====''Amanita citrina''====
Common name: False Death Cap. 
To do.
====''Amanita pantherina''====
Common name: Panther Cap. 
Highly toxic. 
To do.

====''Amanita rubescens''====
Common name: Blusher. 
Edible when cooked. Toxic otherwise. 
Description: To do. 
Similar species: Non-experts may easily confuse ''A. rubescens'' with ''A. pantherina''. To do: describe differences.

====''Amanita virosa''====
Common name: Destroying Angel. 
Deadly toxic. 
To do.
====''Amanita muscaria''====
Commonly known as Fly Amanita or Fly Agaric. 
Edible if correctly prepared<ref name=RubelArora>W. Rubel & D. Arora -- ''A study of cultural bias in field guide determinations of mushroom edibility using the iconic mushroom, Amanita muscaria, as an example''. 2008. Economic Botany vol. 62 no. 3. pp. 223-243. Available [http://mushroomhunter.net/muscaria_revised.pdf here] and [http://www.scribd.com/doc/83723731/Muscaria-Revised here].</ref>, despite the fact that field guides usually<ref name=Branch /><ref name=Jordan /> (incorretly) list it as inedible. Detoxification involves boiling out the water-soluble toxins in water and either vinegar or salt, discarding the water<ref name=RubelArora />. If not detoxified, A. muscaria is hallucinogenic and causes euphoria similar to alcohol intoxification<ref name=Jordan />. Relatively few fatalities have been recorded over several centuries and the lethal dose is not exactly known. The historical evidence collected by Rubel and Arora<ref name=RubelArora /> suggests an adult lethal dose somewhere in the vicinity of 12-20 untreated mushrooms. Symptoms may persist for several days in the most extreme cases<ref name=Jordan /> 
Trivia: ''A. muscaria'' was used for centuries to kill flies. After the crushed mushrooms have been mixed with milk, flies drinking the milk will become so intoxicated that they drown<ref name=Branch /><ref name=RubelArora />. The Sami of Lapland sometimes scatter dried A. muscaria for their reindeer, as the intoxicating effect makes them easier to round up<ref name=Jordan />.
====''Amanita jacksonii''====
To do.

==References==
<references />
[[Category:Food]]
[[Category:Biospherics]]

Fungi

2013-05-29T16:53:41Z

ChristiaanK: Typo

Fungi

2013-05-29T16:52:31Z

ChristiaanK: Oops. Less toxic than some of the others.

Fungi

2013-05-29T16:51:42Z

ChristiaanK: References

Fungi

2013-05-29T16:36:46Z

ChristiaanK: Expanding (WIP)

Organic chemistry

2013-04-28T12:47:28Z

ChristiaanK: More accurate description

Informally, '''organic chemistry''' is the study of molecules containing chains of [[carbon]] atoms (i.e. carbon-carbon bonds). To be more exact, it is the chemistry of carbon with the somewhat arbitrary exclusion of some molecules (such as [[carbon monoxide]]).

==Hydrocarbons==
Hydrocarbons are molecules composed entirely of carbon and [[hydrogen]]. See the [[Hydrocarbon|main article]].

==Organometallics==
Organometallic compounds are molecules containing metal-carbon bonds. For example, buttyllithium (<math>C_6H_5Li</math>) is a hydrocarbon ring in which one hydrogen atom has been replaced with a [[lithium]] atom.

==See also==
*[[Silicon#Chemistry|Chemistry of silicon]]
[[Category:Chemistry]]
{{stub}}

Graphene

2013-04-28T09:44:48Z

ChristiaanK: /* Properties */

'''Graphene''' is a form of [[carbon]], and may informally be thought of as "perfect" [[graphite]]. More specifically, graphene is graphite in which there are no chemical bonds between the individual sheets of graphene, as there normally are in graphite.

==Properties==
[[File:Graphene_heptagon_pentagon_edge.png‎|frame|right|The edge on the right of this graphene sheet has been turned into a pattern of heptagons and pentagons by a microscope.]]
Graphene is optically almost transparent<ref name=Housecroft_Sharpe>C.E. Housecroft & A.G. Sharpe - ''Inorganic chemistry'' 2012. ISBN 978-0-273-74275-3. pp. 1056-1058.</ref>. 
Strictly speaking, graphene is a [[semiconductor]], but it is important to note that this does not imply low conductivity. In fact, graphene has the best electrical conductivity at room temperature of any known material<ref name=Fuhrer>[http://www.nature.com/nnano/journal/v3/n4/full/nnano.2008.58.html M.S. Fuhreer ''et al.''] - ''Intrinsic and extrinsic performance limits of graphene devices on SiO2'' 2008. Nature nanotechnology. Vol. 3 no. 4. pp. 206-209. As quoted by [https://newsdesk.umd.edu/scitech/release.cfm?ArticleID=1621 L. Tune] - ''Physicists show electrons can travel more than 100 times faster in graphene'' 2008. Accessed 2013-04-27.</ref>. The current density in graphene is two to three orders of magnitude better current density than copper<ref name=Housecroft_Sharpe />. This low resistivity exists because the unique properties of graphene cause electrons to behave as massless particles, moving at very nearly the [[speed of light]]<ref name=Housecroft_Sharpe /><ref name=Fuhrer />. 
When the edge of a graphene sheet is examined with a [[transmission electron microscope]], the microscope disrupts the edge and creates a boundary of alternating pentagonal and heptagonal structures.<ref name=Housecroft_Sharpe />

==Graphene oxide==
One derivative of graphene is graphene oxide, imperfect sheets of graphene bound to oxygen atoms. It can be formed by oxidising graphene with certain acids. Unlike graphene, it is an elecrical insulator<ref name=Housecroft_Sharpe />.
The controlled [[reduction]] of graphene oxide can be used to produce materials with electrical properties in between those of graphene and graphene oxide. 

==Production==
Small amounts of graphene can be created from graphite with the use of adhesive tape, [[silica]] and a [[microscope]]. The adhesive tape sticks to the topmost layer of graphite. and the weak bonding between adjacent layers of graphite will break when the tape is pulled off, taking a layer of graphene with it. The graphene can then be deposited on a <math>SiO_2</math> substrate. The microscope is needed because multiple layers of graphite come off in a percentage of cases, and these need to be identified and removed.<ref name=Housecroft_Sharpe /> 
One of the promising ways to increase graphene production is to grow layers of graphene on a wafer of [[silicon carbide]]<ref name=Housecroft_Sharpe />.

==Potential use in spaceflight==
*With its low density and extreme electrical conductivity, graphene could improve the efficiency of almost all electrical systems on a spacecraft.
*Semiconductors based on graphene and/or graphene oxide may someday result in superior computers.
*Along with [[carbon nanotubes]] and [[carbon fibre]], graphene is a good material for spacecraft construction due to its low mass, high strength, low thermal expansion and resistance to thermal shock.

==See also==
*[[Diamond]]
*[[Carbon nanotubes]]
*[[Nanotechnology]]
*[[Superconductor]]
*[[Carbon fibre]]

==References==
<references />
[[Category:Chemistry]]

File:Graphene heptagon pentagon edge.png

2013-04-28T09:41:30Z

ChristiaanK: Graphene. The edge on the right illustrates how the boundary of graphene is modified by a transmission electron microscope. Created with Avogadro: an open-source molecular builder and visualization tool. Version 1.0.3. http://avogadro.openmolecules.net/

Graphene. The edge on the right illustrates how the boundary of graphene is modified by a transmission electron microscope.

Created with Avogadro: an open-source molecular builder and visualization tool. Version 1.0.3. http://avogadro.openmolecules.net/

Carbon nanotube

2013-04-28T09:35:18Z

ChristiaanK: /* Types */

A '''carbon nanotube''' is one [[Carbon nanotube#Types|or more]] concentric sheets of [[graphene]] rolled into tubes. They are amongst the stiffest and strongest materials known to mankind and their electrical properties can be varied from metallic to semiconducting.<ref name=Housecroft_Sharpe>C. Housecroft and A.G. Sharpe - ''Inorganic chemistry'' 4th ed. 2012. ISBN 978-0-273-74275-3 pp. 1058-1061.</ref>

==Types==
[[File:Carbon_nanotube_from_graphene.png|frame|right|Figure 1]]
Carbon nanotubes are classified according to their concentricity, tube thickness and chirality (or zigzag/armchair status, if not chiral). There are also a number of interesting nanotube-derived materials. 
Figure 1 is a graphical depiction of how carbon nanotubes are equivalent to rolled-up graphene. In each of the colours, the solid line (overlapped by the dotted line for yellow) depicts a perpendicular cross-section of the nanotube. (This means that the axis of the tube runs at a right angle to that line.) The two dotted line indicates how the characteristic vector (n, m) of the nanotube is calculated. n is the number of hexagons the horizontal line (which corresponds to a zigzag nanotube) cuts through and m is the number of hexagons that the second dotted line cuts through. (n,m) is (2,2) for A, (4,2) for B, (3,3) for C and (4,0) for D. The tesselation wraps around so that the hexagon centred on O takes the place of the hexagons centred on A to D, respectively. The angle theta indicates how strongly the nanotube spirals, but not whether it is left-handed or right-handed (if chiral) nor how thick it is.
===Layering===
'''Multi-walled carbon nanotubes''' (MWNT) consist of more than one tube of different sizes inside one another. Single tubes are known as '''single-walled carbon nanotubes''' (SWNT).<ref name=Housecroft_Sharpe /> 
===Chirality===
[[File:SWNT_4_2_LH.png‎|frame|left|Figure 2]]
The shape of a carbon nanotube can be described using the value <math>\theta</math>, the (absolute value of the) angle at which it is twisted (relative to a zigzag nanotube) when this tube is conceptually made from a sheet of graphite.
*<math>\theta = 0^\circ</math> for '''zigzag nanotubes''', which may be metallic conductors or semiconductors. A cross-section of a zigzag carbon nanotube forms a tidy zigzag pattern.
*<math>\theta = 30^\circ</math> for '''armchair''' nanotubes, which are [[metal|metallic conductors]]. A cross-section of an armchair carbon nanotube forms a stepped pattern.
*<math>0^\circ < \theta < 30^\circ</math> for all other nanotubes, which are called [[chirality|chiral]] carbon nanotubes. They may be either left-handed (following the adjacent hexagons in a clockwise direction leads you to spiral upwards along the tube) or right-handed (following the adjacednt hexagons in an anticlockwise direction leads you to spiral upwards along the tube). Chiral nanotubes may be metallic conductors or semiconductors. 
To more fully describe a carbon nanotube, the value <math>C_h = na_1 + ma_2</math> can be used. The values of <math>a_1</math> and <math>a_2</math> are the widths of the hexagons which make up the nanotube, measured respectively in the directions in which n and m are measured (see Figure 1). <math>C_h = na_1 + ma_2</math> is the Manhattan distance for one full revolution around the tube. For zigzag nanotubes, <math>m=0</math> and for armchair nanotubes, <math>m=n</math>. 
Figure 2 illustrates a left-handed SWNT (4,2). Note that if you were to complete the partially cut-off hexagon on the right of the side-view and then continue with those that follow, you would spiral to the right according to the [[chirality|left-hand rule]].

===Modified carbon nanotubes===
It is sometimes desirable to modify carbon nanotubes to make them soluble in either water or organic solvents, bond them to another material or perform some other function. 
One of the ways to achieve this is to react the carbon nanotubes with chemicals, such as [[fluorine]], which can bond to their surface. Since each carbon atom has a double bond with one of its neigbours, it is possible to bond carbon nanotubes to other molecules or elements without disrupting the physical structure. However, this reduces electrical conductivity.<ref name=Housecroft_Sharpe />. 

==Production==
Commercial production of carbon nanotubes takes place by [[chemical vapour deposition]], laser vaporisation (of [[graphite]]) or electrical arcing between graphite electrodes<ref name=Housecroft_Sharpe />. The electric arc method tends to create MWNTs. Lengths produced are currently in the micrometre range, while thicknesses vary from about 1nm for the thinnest SWNTs and 100nm for the thickest MWNTs<ref name=Housecroft_Sharpe />

==Possible uses in space travel==
*Carbon nanotubes are perhaps most notable for their extreme tensile strength, making them an ideal material for spacecraft construction.
*They are also one of the only materials which have a high enough tensile strength that they might, possibly, enable a [[space elevator]] on earth.
*The electrical properties of carbon nanotubes suggest that they might some day be used in computers.
*Excellent resistance to thermal shock and high temperatures (which is shared by all forms of graphite, graphene, carbon nanotubes and carbon fibre), in combination with high tensile strength, raises the question of whether hypersonic parachute designs might improve the usefulness of [[aerobraking]].

==See also==
* [[Carbon]]
* [[Diamond]]
* [[Graphite]]
* [[Graphene]]
* [[Charcoal]]
* [[Coal]]
* [[Nanotechnology]]

==References==
<references />

[[Category:Chemistry]]

Talk:Carbon nanotube

2013-04-28T09:25:13Z

ChristiaanK:

There's a mistake in Figure 1. B has m=0. I can't upload a new version; for some odd reason the old one stays. [[User:ChristiaanK|ChristiaanK]] 09:24, 28 April 2013 (UTC)
:Nevermind. It just takes a few minutes.[[User:ChristiaanK|ChristiaanK]] 09:25, 28 April 2013 (UTC)

Talk:Carbon nanotube

2013-04-28T09:24:38Z

ChristiaanK: Didn't sign

There's a mistake in Figure 1. B has m=0. I can't upload a new version; for some odd reason the old one stays. [[User:ChristiaanK|ChristiaanK]] 09:24, 28 April 2013 (UTC)

Talk:Carbon nanotube

2013-04-28T09:24:20Z

ChristiaanK: Erratum

There's a mistake in Figure 1. B has m=0. I can't upload a new version; for some odd reason the old one stays.

File:Carbon nanotube from graphene.png

2013-04-28T09:22:40Z

ChristiaanK: uploaded a new version of "File:Carbon nanotube from graphene.png": Uploaded the wrong file last time.

Graphical depiction of how carbon nanotubes are equivalent to rolled-up graphene. In each of the colours, the solid line (overlapped by the dotted line for yellow) depicts a cross-section of the nanotube. The two dotted line indicates how the characteristic vector (n, m) of the nanotube is calculated. The tesselation wraps around so that the hexagon centred on O takes the place of the hexagons centred on A to D, respectively. The angle theta indicates how strongly the nanotube spirals, but not whether it is left-handed or right-handed (if chiral) nor how thick it is.

File:Carbon nanotube from graphene.png

2013-04-28T09:20:42Z

ChristiaanK: uploaded a new version of "File:Carbon nanotube from graphene.png": Made the image smaller still. (There's also a mistake in the old version. B has m=2, not m=0.)

Carbon nanotube

2013-04-28T09:03:12Z

ChristiaanK: Add image

A '''carbon nanotube''' is one [[Carbon nanotube#Types|or more]] concentric sheets of [[graphene]] rolled into tubes. They are amongst the stiffest and strongest materials known to mankind and their electrical properties can be varied from metallic to semiconducting.<ref name=Housecroft_Sharpe>C. Housecroft and A.G. Sharpe - ''Inorganic chemistry'' 4th ed. 2012. ISBN 978-0-273-74275-3 pp. 1058-1061.</ref>

==Types==
[[File:Carbon_nanotube_from_graphene.png|frame|right|Figure 1]]
Carbon nanotubes are classified according to their concentricity, tube thickness and chirality (or zigzag/armchair status, if not chiral). There are also a number of interesting nanotube-derived materials. 
Figure 1 is a graphical depiction of how carbon nanotubes are equivalent to rolled-up graphene. In each of the colours, the solid line (overlapped by the dotted line for yellow) depicts a perpendicular cross-section of the nanotube. (This means that the axis of the tube runs at a right angle to that line.) The two dotted line indicates how the characteristic vector (n, m) of the nanotube is calculated. The tesselation wraps around so that the hexagon centred on O takes the place of the hexagons centred on A to D, respectively. The angle theta indicates how strongly the nanotube spirals, but not whether it is left-handed or right-handed (if chiral) nor how thick it is.
===Layering===
'''Multi-walled carbon nanotubes''' (MWNT) consist of more than one tube of different sizes inside one another. Single tubes are known as '''single-walled carbon nanotubes''' (SWNT).<ref name=Housecroft_Sharpe /> 
===Chirality===
[[File:SWNT_4_2_LH.png‎|frame|left|Figure 2]]
The shape of a carbon nanotube can be described using the value <math>\theta</math>, the (absolute value of the) angle at which it is twisted (relative to a zigzag nanotube) when this tube is conceptually made from a sheet of graphite.
*<math>\theta = 0^\circ</math> for '''zigzag nanotubes''', which may be metallic conductors or semiconductors. A cross-section of a zigzag carbon nanotube forms a tidy zigzag pattern.
*<math>\theta = 30^\circ</math> for '''armchair''' nanotubes, which are [[metal|metallic conductors]]. A cross-section of an armchair carbon nanotube forms a stepped pattern.
*<math>0^\circ < \theta < 30^\circ</math> for all other nanotubes, which are called [[chirality|chiral]] carbon nanotubes. They may be either left-handed (following the adjacent hexagons in a clockwise direction leads you to spiral upwards along the tube) or right-handed (following the adjacednt hexagons in an anticlockwise direction leads you to spiral upwards along the tube). Chiral nanotubes may be metallic conductors or semiconductors. 
To more fully describe a carbon nanotube, the value <math>C_h = na_1 + ma_2</math> can be used. The values of <math>a_1</math> and <math>a_2</math> are the widths of the hexagons which make up the nanotube, measured respectively in the directions in which n and m are measured (see Figure 1). <math>C_h = na_1 + ma_2</math> is the Manhattan distance for one full revolution around the tube. For zigzag nanotubes, <math>m=0</math> and for armchair nanotubes, <math>m=n</math>.

===Modified carbon nanotubes===
It is sometimes desirable to modify carbon nanotubes to make them soluble in either water or organic solvents, bond them to another material or perform some other function. 
One of the ways to achieve this is to react the carbon nanotubes with chemicals, such as [[fluorine]], which can bond to their surface. Since each carbon atom has a double bond with one of its neigbours, it is possible to bond carbon nanotubes to other molecules or elements without disrupting the physical structure. However, this reduces electrical conductivity.<ref name=Housecroft_Sharpe />. 

==Production==
Commercial production of carbon nanotubes takes place by [[chemical vapour deposition]], laser vaporisation (of [[graphite]]) or electrical arcing between graphite electrodes<ref name=Housecroft_Sharpe />. The electric arc method tends to create MWNTs. Lengths produced are currently in the micrometre range, while thicknesses vary from about 1nm for the thinnest SWNTs and 100nm for the thickest MWNTs<ref name=Housecroft_Sharpe />

==Possible uses in space travel==
*Carbon nanotubes are perhaps most notable for their extreme tensile strength, making them an ideal material for spacecraft construction.
*They are also one of the only materials which have a high enough tensile strength that they might, possibly, enable a [[space elevator]] on earth.
*The electrical properties of carbon nanotubes suggest that they might some day be used in computers.
*Excellent resistance to thermal shock and high temperatures (which is shared by all forms of graphite, graphene, carbon nanotubes and carbon fibre), in combination with high tensile strength, raises the question of whether hypersonic parachute designs might improve the usefulness of [[aerobraking]].

==See also==
* [[Carbon]]
* [[Diamond]]
* [[Graphite]]
* [[Graphene]]
* [[Charcoal]]
* [[Coal]]
* [[Nanotechnology]]

==References==
<references />

[[Category:Chemistry]]

File:SWNT 4 2 LH.png

2013-04-28T08:57:00Z

ChristiaanK: Left-handed chiral carbon nanotube with n=4 and m=2. Created with Avogadro: an open-source molecular builder and visualization tool. Version 1.0.3. http://avogadro.openmolecules.net/

Left-handed chiral carbon nanotube with n=4 and m=2.

Created with Avogadro: an open-source molecular builder and visualization tool. Version 1.0.3. http://avogadro.openmolecules.net/

Carbon nanotube

2013-04-28T08:52:33Z

ChristiaanK: See also

A '''carbon nanotube''' is one [[Carbon nanotube#Types|or more]] concentric sheets of [[graphene]] rolled into tubes. They are amongst the stiffest and strongest materials known to mankind and their electrical properties can be varied from metallic to semiconducting.<ref name=Housecroft_Sharpe>C. Housecroft and A.G. Sharpe - ''Inorganic chemistry'' 4th ed. 2012. ISBN 978-0-273-74275-3 pp. 1058-1061.</ref>

==Types==
[[File:Carbon_nanotube_from_graphene.png|frame|right|Figure 1]]
Carbon nanotubes are classified according to their concentricity, tube thickness and chirality (or zigzag/armchair status, if not chiral). There are also a number of interesting nanotube-derived materials. 
Figure 1 is a graphical depiction of how carbon nanotubes are equivalent to rolled-up graphene. In each of the colours, the solid line (overlapped by the dotted line for yellow) depicts a perpendicular cross-section of the nanotube. (This means that the axis of the tube runs at a right angle to that line.) The two dotted line indicates how the characteristic vector (n, m) of the nanotube is calculated. The tesselation wraps around so that the hexagon centred on O takes the place of the hexagons centred on A to D, respectively. The angle theta indicates how strongly the nanotube spirals, but not whether it is left-handed or right-handed (if chiral) nor how thick it is.
===Layering===
'''Multi-walled carbon nanotubes''' (MWNT) consist of more than one tube of different sizes inside one another. Single tubes are known as '''single-walled carbon nanotubes''' (SWNT).<ref name=Housecroft_Sharpe /> 
===Chirality===
The shape of a carbon nanotube can be described using the value <math>\theta</math>, the (absolute value of the) angle at which it is twisted (relative to a zigzag nanotube) when this tube is conceptually made from a sheet of graphite.
*<math>\theta = 0^\circ</math> for '''zigzag nanotubes''', which may be metallic conductors or semiconductors. A cross-section of a zigzag carbon nanotube forms a tidy zigzag pattern.
*<math>\theta = 30^\circ</math> for '''armchair''' nanotubes, which are [[metal|metallic conductors]]. A cross-section of an armchair carbon nanotube forms a stepped pattern.
*<math>0^\circ < \theta < 30^\circ</math> for all other nanotubes, which are called [[chirality|chiral]] carbon nanotubes. They may be either left-handed (following the adjacent hexagons in a clockwise direction leads you to spiral upwards along the tube) or right-handed (following the adjacednt hexagons in an anticlockwise direction leads you to spiral upwards along the tube). Chiral nanotubes may be metallic conductors or semiconductors. 
To more fully describe a carbon nanotube, the value <math>C_h = na_1 + ma_2</math> can be used. The values of <math>a_1</math> and <math>a_2</math> are the widths of the hexagons which make up the nanotube, measured respectively in the directions in which n and m are measured (see Figure 1). <math>C_h = na_1 + ma_2</math> is the Manhattan distance for one full revolution around the tube. For zigzag nanotubes, <math>m=0</math> and for armchair nanotubes, <math>m=n</math>.

===Modified carbon nanotubes===
It is sometimes desirable to modify carbon nanotubes to make them soluble in either water or organic solvents, bond them to another material or perform some other function. 
One of the ways to achieve this is to react the carbon nanotubes with chemicals, such as [[fluorine]], which can bond to their surface. Since each carbon atom has a double bond with one of its neigbours, it is possible to bond carbon nanotubes to other molecules or elements without disrupting the physical structure. However, this reduces electrical conductivity.<ref name=Housecroft_Sharpe />. 

==Production==
Commercial production of carbon nanotubes takes place by [[chemical vapour deposition]], laser vaporisation (of [[graphite]]) or electrical arcing between graphite electrodes<ref name=Housecroft_Sharpe />. The electric arc method tends to create MWNTs. Lengths produced are currently in the micrometre range, while thicknesses vary from about 1nm for the thinnest SWNTs and 100nm for the thickest MWNTs<ref name=Housecroft_Sharpe />

==Possible uses in space travel==
*Carbon nanotubes are perhaps most notable for their extreme tensile strength, making them an ideal material for spacecraft construction.
*They are also one of the only materials which have a high enough tensile strength that they might, possibly, enable a [[space elevator]] on earth.
*The electrical properties of carbon nanotubes suggest that they might some day be used in computers.
*Excellent resistance to thermal shock and high temperatures (which is shared by all forms of graphite, graphene, carbon nanotubes and carbon fibre), in combination with high tensile strength, raises the question of whether hypersonic parachute designs might improve the usefulness of [[aerobraking]].

==See also==
* [[Carbon]]
* [[Diamond]]
* [[Graphite]]
* [[Graphene]]
* [[Charcoal]]
* [[Coal]]
* [[Nanotechnology]]

==References==
<references />

[[Category:Chemistry]]

Carbon nanotube

2013-04-28T08:46:57Z

ChristiaanK: /* Chirality */

A '''carbon nanotube''' is one [[Carbon nanotube#Types|or more]] concentric sheets of [[graphene]] rolled into tubes. They are amongst the stiffest and strongest materials known to mankind and their electrical properties can be varied from metallic to semiconducting.<ref name=Housecroft_Sharpe>C. Housecroft and A.G. Sharpe - ''Inorganic chemistry'' 4th ed. 2012. ISBN 978-0-273-74275-3 pp. 1058-1061.</ref>

==Types==
[[File:Carbon_nanotube_from_graphene.png|frame|right|Figure 1]]
Carbon nanotubes are classified according to their concentricity, tube thickness and chirality (or zigzag/armchair status, if not chiral). There are also a number of interesting nanotube-derived materials. 
Figure 1 is a graphical depiction of how carbon nanotubes are equivalent to rolled-up graphene. In each of the colours, the solid line (overlapped by the dotted line for yellow) depicts a perpendicular cross-section of the nanotube. (This means that the axis of the tube runs at a right angle to that line.) The two dotted line indicates how the characteristic vector (n, m) of the nanotube is calculated. The tesselation wraps around so that the hexagon centred on O takes the place of the hexagons centred on A to D, respectively. The angle theta indicates how strongly the nanotube spirals, but not whether it is left-handed or right-handed (if chiral) nor how thick it is.
===Layering===
'''Multi-walled carbon nanotubes''' (MWNT) consist of more than one tube of different sizes inside one another. Single tubes are known as '''single-walled carbon nanotubes''' (SWNT).<ref name=Housecroft_Sharpe /> 
===Chirality===
The shape of a carbon nanotube can be described using the value <math>\theta</math>, the (absolute value of the) angle at which it is twisted (relative to a zigzag nanotube) when this tube is conceptually made from a sheet of graphite.
*<math>\theta = 0^\circ</math> for '''zigzag nanotubes''', which may be metallic conductors or semiconductors. A cross-section of a zigzag carbon nanotube forms a tidy zigzag pattern.
*<math>\theta = 30^\circ</math> for '''armchair''' nanotubes, which are [[metal|metallic conductors]]. A cross-section of an armchair carbon nanotube forms a stepped pattern.
*<math>0^\circ < \theta < 30^\circ</math> for all other nanotubes, which are called [[chirality|chiral]] carbon nanotubes. They may be either left-handed (following the adjacent hexagons in a clockwise direction leads you to spiral upwards along the tube) or right-handed (following the adjacednt hexagons in an anticlockwise direction leads you to spiral upwards along the tube). Chiral nanotubes may be metallic conductors or semiconductors. 
To more fully describe a carbon nanotube, the value <math>C_h = na_1 + ma_2</math> can be used. The values of <math>a_1</math> and <math>a_2</math> are the widths of the hexagons which make up the nanotube, measured respectively in the directions in which n and m are measured (see Figure 1). <math>C_h = na_1 + ma_2</math> is the Manhattan distance for one full revolution around the tube. For zigzag nanotubes, <math>m=0</math> and for armchair nanotubes, <math>m=n</math>.

===Modified carbon nanotubes===
It is sometimes desirable to modify carbon nanotubes to make them soluble in either water or organic solvents, bond them to another material or perform some other function. 
One of the ways to achieve this is to react the carbon nanotubes with chemicals, such as [[fluorine]], which can bond to their surface. Since each carbon atom has a double bond with one of its neigbours, it is possible to bond carbon nanotubes to other molecules or elements without disrupting the physical structure. However, this reduces electrical conductivity.<ref name=Housecroft_Sharpe />. 

==Production==
Commercial production of carbon nanotubes takes place by [[chemical vapour deposition]], laser vaporisation (of [[graphite]]) or electrical arcing between graphite electrodes<ref name=Housecroft_Sharpe />. The electric arc method tends to create MWNTs. Lengths produced are currently in the micrometre range, while thicknesses vary from about 1nm for the thinnest SWNTs and 100nm for the thickest MWNTs<ref name=Housecroft_Sharpe />

==Possible uses in space travel==
*Carbon nanotubes are perhaps most notable for their extreme tensile strength, making them an ideal material for spacecraft construction.
*They are also one of the only materials which have a high enough tensile strength that they might, possibly, enable a [[space elevator]] on earth.
*The electrical properties of carbon nanotubes suggest that they might some day be used in computers.
*Excellent resistance to thermal shock and high temperatures (which is shared by all forms of graphite, graphene, carbon nanotubes and carbon fibre), in combination with high tensile strength, raises the question of whether hypersonic parachute designs might improve the usefulness of [[aerobraking]].

==References==
<references />

[[Category:Chemistry]]

Carbon nanotube

2013-04-28T08:44:58Z

ChristiaanK: /* Chirality */

A '''carbon nanotube''' is one [[Carbon nanotube#Types|or more]] concentric sheets of [[graphene]] rolled into tubes. They are amongst the stiffest and strongest materials known to mankind and their electrical properties can be varied from metallic to semiconducting.<ref name=Housecroft_Sharpe>C. Housecroft and A.G. Sharpe - ''Inorganic chemistry'' 4th ed. 2012. ISBN 978-0-273-74275-3 pp. 1058-1061.</ref>

==Types==
[[File:Carbon_nanotube_from_graphene.png|frame|right|Figure 1]]
Carbon nanotubes are classified according to their concentricity, tube thickness and chirality (or zigzag/armchair status, if not chiral). There are also a number of interesting nanotube-derived materials. 
Figure 1 is a graphical depiction of how carbon nanotubes are equivalent to rolled-up graphene. In each of the colours, the solid line (overlapped by the dotted line for yellow) depicts a perpendicular cross-section of the nanotube. (This means that the axis of the tube runs at a right angle to that line.) The two dotted line indicates how the characteristic vector (n, m) of the nanotube is calculated. The tesselation wraps around so that the hexagon centred on O takes the place of the hexagons centred on A to D, respectively. The angle theta indicates how strongly the nanotube spirals, but not whether it is left-handed or right-handed (if chiral) nor how thick it is.
===Layering===
'''Multi-walled carbon nanotubes''' (MWNT) consist of more than one tube of different sizes inside one another. Single tubes are known as '''single-walled carbon nanotubes''' (SWNT).<ref name=Housecroft_Sharpe /> 
===Chirality===
The shape of a carbon nanotube can be described using the value <math>\theta</math>, the (absolute value of the) angle at which it is twisted (relative to a zigzag nanotube) when this tube is conceptually made from a sheet of graphite.
*<math>\theta = 0^\circ</math> for '''zigzag nanotubes''', which may be metallic conductors or semiconductors. A cross-section of a zigzag carbon nanotube forms a tidy zigzag pattern.
*<math>\theta = 30^\circ</math> for '''armchair''' nanotubes, which are [[metal|metallic conductors]]. A cross-section of an armchair carbon nanotube forms a stepped pattern.
*<math>0^\circ < \theta < 30^\circ</math> for all other nanotubes, which are called [[chirality|chiral]] carbon nanotubes. They may be either left-handed (following the adjacent hexagons in a clockwise direction leads you to spiral upwards along the tube) or right-handed (following the adjacednt hexagons in an anticlockwise direction leads you to spiral upwards along the tube). Chiral nanotubes may be metallic conductors or semiconductors. 
To more fully describe a carbon nanotube, the value <math>C_h = na_1 + ma_2</math> can be used. The values of <math>a_1</math> and <math>a_2</math> are the widths of the hexagons which make up the nanotube, measured respectively in the directions in which n and m are measured (see Figure 1). <math>C_h = na_1 + ma_2</math> is the Manhattan distance for one full revolution around the tube.

===Modified carbon nanotubes===
It is sometimes desirable to modify carbon nanotubes to make them soluble in either water or organic solvents, bond them to another material or perform some other function. 
One of the ways to achieve this is to react the carbon nanotubes with chemicals, such as [[fluorine]], which can bond to their surface. Since each carbon atom has a double bond with one of its neigbours, it is possible to bond carbon nanotubes to other molecules or elements without disrupting the physical structure. However, this reduces electrical conductivity.<ref name=Housecroft_Sharpe />. 

==Production==
Commercial production of carbon nanotubes takes place by [[chemical vapour deposition]], laser vaporisation (of [[graphite]]) or electrical arcing between graphite electrodes<ref name=Housecroft_Sharpe />. The electric arc method tends to create MWNTs. Lengths produced are currently in the micrometre range, while thicknesses vary from about 1nm for the thinnest SWNTs and 100nm for the thickest MWNTs<ref name=Housecroft_Sharpe />

==Possible uses in space travel==
*Carbon nanotubes are perhaps most notable for their extreme tensile strength, making them an ideal material for spacecraft construction.
*They are also one of the only materials which have a high enough tensile strength that they might, possibly, enable a [[space elevator]] on earth.
*The electrical properties of carbon nanotubes suggest that they might some day be used in computers.
*Excellent resistance to thermal shock and high temperatures (which is shared by all forms of graphite, graphene, carbon nanotubes and carbon fibre), in combination with high tensile strength, raises the question of whether hypersonic parachute designs might improve the usefulness of [[aerobraking]].

==References==
<references />

[[Category:Chemistry]]

Graphite

2013-04-28T08:39:56Z

ChristiaanK: /* Uses */

'''Graphite''' is a form of high-purity [[carbon]] which occurs on Earth as a [[mineral]]. It can also be artificially produced from [[silicon carbide]]. 
[[Coke]] and [[charcoal]] are not as pure as graphite because, while the carbonizing process does boil off [[volatiles]] in their production, non-volatile ash remains.

==Physical characteristics==
Graphite has a hardness of 1 to 2 on Mohs' scale, a black streak, a lustre varying from metallic to dull and earthy, a hexagonal crystal system and specific gravity between 2.1 and 2.23.<ref name=Cairncross>B. Cairncross - ''Field guide to rocks and minerals of Southern Africa'' 2004. ISBN 978-1-86872-985-2 p. 123</ref>

==Occurence==
Graphite occurs on Earth in [[igneous rock|igneous]] and [[metamorphic rock]], sometimes as metamorphosed [[coal]]. It can also be found in [[limestone]]. Some [[meteorites]] contain graphite.

==Uses==
* [[Refractory]]
* [[Graphene]] production
* [[Carbon nanotube]] production

==Open issues==
* How common are graphitic rocks on Mars?
* How common are graphite-containing meteorites on Mars?

==References==
<references />

[[Category:Geology]]
[[Category:Chemistry]]

Carbon nanotube

2013-04-28T08:38:44Z

ChristiaanK: /* Types */

A '''carbon nanotube''' is one [[Carbon nanotube#Types|or more]] concentric sheets of [[graphene]] rolled into tubes. They are amongst the stiffest and strongest materials known to mankind and their electrical properties can be varied from metallic to semiconducting.<ref name=Housecroft_Sharpe>C. Housecroft and A.G. Sharpe - ''Inorganic chemistry'' 4th ed. 2012. ISBN 978-0-273-74275-3 pp. 1058-1061.</ref>

==Types==
[[File:Carbon_nanotube_from_graphene.png|frame|right|Figure 1]]
Carbon nanotubes are classified according to their concentricity, tube thickness and chirality (or zigzag/armchair status, if not chiral). There are also a number of interesting nanotube-derived materials. 
Figure 1 is a graphical depiction of how carbon nanotubes are equivalent to rolled-up graphene. In each of the colours, the solid line (overlapped by the dotted line for yellow) depicts a perpendicular cross-section of the nanotube. (This means that the axis of the tube runs at a right angle to that line.) The two dotted line indicates how the characteristic vector (n, m) of the nanotube is calculated. The tesselation wraps around so that the hexagon centred on O takes the place of the hexagons centred on A to D, respectively. The angle theta indicates how strongly the nanotube spirals, but not whether it is left-handed or right-handed (if chiral) nor how thick it is.
===Layering===
'''Multi-walled carbon nanotubes''' (MWNT) consist of more than one tube of different sizes inside one another. Single tubes are known as '''single-walled carbon nanotubes''' (SWNT).<ref name=Housecroft_Sharpe /> 
===Chirality===
The shape of a carbon nanotube can be described using the value <math>\theta</math>, the (absolute value of the) angle at which it is twisted (relative to a zigzag nanotube) when this tube is conceptually made from a sheet of graphite.
*<math>\theta = 0^\circ</math> for '''zigzag nanotubes''', which may be metallic conductors or semiconductors. A cross-section of a zigzag carbon nanotube forms a tidy zigzag pattern.
*<math>\theta = 30^\circ</math> for '''armchair''' nanotubes, which are [[metal|metallic conductors]]. A cross-section of an armchair carbon nanotube forms a stepped pattern.
*<math>0^\circ < \theta < 30^\circ</math> for all other nanotubes, which are called [[chirality|chiral]] carbon nanotubes. They may be either left-handed (following the adjacent hexagons in a clockwise direction leads you to spiral upwards along the tube) or right-handed (following the adjacednt hexagons in an anticlockwise direction leads you to spiral upwards along the tube). Chiral nanotubes may be metallic conductors or semiconductors. 
To more fully describe a carbon nanotube, the value <math>C_h = na_1 + ma_2</math> can be used. The values of <math>a_1</math> and <math>a_2</math> are the widths of the hexagons which make up the nanotube, measured respectively in the directions in which n and m are measured (see image). <math>C_h = na_1 + ma_2</math> is the Manhattan distance for one full revolution around the tube.

===Modified carbon nanotubes===
It is sometimes desirable to modify carbon nanotubes to make them soluble in either water or organic solvents, bond them to another material or perform some other function. 
One of the ways to achieve this is to react the carbon nanotubes with chemicals, such as [[fluorine]], which can bond to their surface. Since each carbon atom has a double bond with one of its neigbours, it is possible to bond carbon nanotubes to other molecules or elements without disrupting the physical structure. However, this reduces electrical conductivity.<ref name=Housecroft_Sharpe />. 

==Production==
Commercial production of carbon nanotubes takes place by [[chemical vapour deposition]], laser vaporisation (of [[graphite]]) or electrical arcing between graphite electrodes<ref name=Housecroft_Sharpe />. The electric arc method tends to create MWNTs. Lengths produced are currently in the micrometre range, while thicknesses vary from about 1nm for the thinnest SWNTs and 100nm for the thickest MWNTs<ref name=Housecroft_Sharpe />

==Possible uses in space travel==
*Carbon nanotubes are perhaps most notable for their extreme tensile strength, making them an ideal material for spacecraft construction.
*They are also one of the only materials which have a high enough tensile strength that they might, possibly, enable a [[space elevator]] on earth.
*The electrical properties of carbon nanotubes suggest that they might some day be used in computers.
*Excellent resistance to thermal shock and high temperatures (which is shared by all forms of graphite, graphene, carbon nanotubes and carbon fibre), in combination with high tensile strength, raises the question of whether hypersonic parachute designs might improve the usefulness of [[aerobraking]].

==References==
<references />

[[Category:Chemistry]]

File:Carbon nanotube from graphene.png

2013-04-28T08:36:20Z

ChristiaanK: uploaded a new version of "File:Carbon nanotube from graphene.png": I've replaced this file with a small version, since the server doesn't seem to generate thumbnails. Graphical depiction of how carbon nanotubes are equivalent to rolled-up graphe

Hydrocarbons

2013-04-28T06:53:08Z

ChristiaanK: Fix hydrogen count

'''Hydrocarbons''' are a class of [[molecules]] comprised of [[carbon]] and [[hydrogen]]. They can range in size from one carbon atom with four hydrogen atoms ([[methane]]) to long chains and rings.

==Significance for a Martian colony==
The manufacturing of hydrocarbons is inevitable for a [[colony]] on [[Mars]]. As an intermediate product they are a resource to manufacture a great variety of vital products that are made from [[synthetic materials]], such as [[space suit]]s, [[pneumatics|gaskets]], etc.

Liquid hydrocarbons can be used for [[energy storage]]. Accumulated in large tanks, they can be oxidized on demand.

== Hydrocarbon Molecules ==
===Alkanes===
'''[[Alkanes]]''' are non-cyclical hydrocarbons containing only single bonds between carbon and hydrogen atoms.
*[[Methane]] CH4
*[[Ethane]] C2H6
*[[Propane]] C3H8
*[[Butane]] & [[Isobutane]] C4H10
*[[Pentane]], [[Isopentane]], & [[Neopentane]] C5H12

===Cycloalkanes===
'''[[Cycloalkanes]]''' are cyclical hydrocarbons containing only single bonds between carbon and hydrogen atoms.
*Cyclopropane C3H6

===Alkenes===
'''[[Alkenes]]''' are hydrocarbons containing at least one double carbon bond.
*[[Ethylene]] C2H4

===Alkynes===
'''[[Alkynes]]''', also called '''acetylenes''', are hydrocarbons containing at least one triple carbon bond.
*[[Ethyne]] (<math>C_2H_2</math>) is the simplest possible alkyne.

===Alcohols===
Alcohols are hydrocarbons containing a hydroxyl functional group (OH). They are liquid and, therefore, can be stored easily without high pressure or low temperature. Alcohols can be used as fuel, producing heat when oxidized, with [[water]] and [[carbon dioxide]] as reaction products.
*[[Methanol]]
*[[Ethanol]]

== Synthesis ==
Hydrocarbons are common in organic chemistry. They can also be [[Hydrocarbon synthesis|produced artificially]] through chemical reactions.

[[category:chemistry]]
[[category:hydrocarbons]]
{{stub}}

Hydrocarbons

2013-04-28T06:51:44Z

ChristiaanK: Added class

'''Hydrocarbons''' are a class of [[molecules]] comprised of [[carbon]] and [[hydrogen]]. They can range in size from one carbon atom with four hydrogen atoms ([[methane]]) to long chains and rings.

==Significance for a Martian colony==
The manufacturing of hydrocarbons is inevitable for a [[colony]] on [[Mars]]. As an intermediate product they are a resource to manufacture a great variety of vital products that are made from [[synthetic materials]], such as [[space suit]]s, [[pneumatics|gaskets]], etc.

Liquid hydrocarbons can be used for [[energy storage]]. Accumulated in large tanks, they can be oxidized on demand.

== Hydrocarbon Molecules ==
===Alkanes===
'''[[Alkanes]]''' are non-cyclical hydrocarbons containing only single bonds between carbon and hydrogen atoms.
*[[Methane]] CH4
*[[Ethane]] C2H6
*[[Propane]] C3H8
*[[Butane]] & [[Isobutane]] C4H10
*[[Pentane]], [[Isopentane]], & [[Neopentane]] C5H12

===Cycloalkanes===
'''[[Cycloalkanes]]''' are cyclical hydrocarbons containing only single bonds between carbon and hydrogen atoms.
*Cyclopropane C3H8

===Alkenes===
'''[[Alkenes]]''' are hydrocarbons containing at least one double carbon bond.
*[[Ethylene]] C2H4

===Alkynes===
'''[[Alkynes]]''', also called '''acetylenes''', are hydrocarbons containing at least one triple carbon bond.
*[[Ethyne]] (<math>C_2H_2</math>) is the simplest possible alkyne.

===Alcohols===
Alcohols are hydrocarbons containing a hydroxyl functional group (OH). They are liquid and, therefore, can be stored easily without high pressure or low temperature. Alcohols can be used as fuel, producing heat when oxidized, with [[water]] and [[carbon dioxide]] as reaction products.
*[[Methanol]]
*[[Ethanol]]

== Synthesis ==
Hydrocarbons are common in organic chemistry. They can also be [[Hydrocarbon synthesis|produced artificially]] through chemical reactions.

[[category:chemistry]]
[[category:hydrocarbons]]
{{stub}}

Organic chemistry

2013-04-28T06:45:56Z

ChristiaanK: Created page.

'''Organic chemistry''' is the study of molecules containing chains of carbon atoms (i.e. carbon-carbon bonds).

==Hydrocarbons==
Hydrocarbons are molecules composed entirely of carbon and [[hydrogen]]. See the [[Hydrocarbon|main article]].

==Organometallics==
Organometallic compounds are molecules containing metal-carbon bonds. For example, buttyllithium (<math>C_6H_5Li</math>) is a hydrocarbon ring in which one hydrogen atom has been replaced with a [[lithium]] atom.

==See also==
*[[Silicon#Chemistry|Chemistry of silicon]]
[[Category:Chemistry]]
{{stub}}

Silicon

2013-04-28T06:32:36Z

ChristiaanK: Expanded

{{element|elementSymbol=Si|elementName=Silicon|protons=14|abundance=?% ([[regolith]])}}
'''Silicon''' (''periodic table symbol:'' Si14) is a chemical element that can be found in several [[minerals]] on [[Mars]].

==Chemistry==
[[File:Cyclohexasilane_cyclohexane_cyclohexasiloxane.png‎|frame|right|Structure of cyclohexasilane (top), cyclohexasiloxane (bottom right) and the [[hydrocarbon]] cyclohexane (bottom left).]]
As a group 14 element, silicon has a chemsitry similar to that of [[tin]] and [[lead]], and especially that of [[carbon]] and [[germanium]]. 
As we go down from carbon at the top of group 14, the reactivity (and electropositivity) of the elements increases. At the same time, the bond [[enthalpy]] decreases for chains of the element<ref name=Housecroft_Sharpe>C.E. Housecroft & A.G. Sharpe - ''Inorganic chemistry'' 2012. ISBN 978-0-273-74275-3 pp. 433, 444-446.</ref>. That is, C-C bonds are more stable than Si-Si bonds, which are more stable than Ge-Ge bonds, etc. The strength of their bonds with hydrogen similarly decreases. This is why, for example, [[methane]] is more stable than [[Silicon#Silanes|silane]]. 
Despite the instability of silicon chains relative to their carbon analogues, they are industrially significant.

===Silanes===
The silanes are acyclic chains of singly-bonded silicon atoms analogous to the [[alkanes]]. The cyclosilanes are (highly unstable) cyclic silanes.

===Silenes===
The silenes are acyclic chains of doubly-bonded silicon atoms, analogous to the [[alkenes]].

===Siloxanes===
Due to the instability of Si-Si bonds, longer chains of silicon atoms are often constructed with some other atom between the silicon atoms, which bonds more strongly to them. In the case of the siloxanes, this results in Si-O-Si chains. For comparison, the enthalpy of a Si-O bond is in higher than that of a C-C single bond but lower than that of a C=C double bond, and more than twice that of a Si-Si bond.

==Occurence==
Silicon is the second most common element in the earth's crust (after [[oxygen]]); in fact their compound [[silica]] makes up about 60% of the crust. 
Analysis of Martian soil<ref name=Pathfinder>NASA JPL - [http://mars.jpl.nasa.gov/MPF/science/apxs_elemental.html ''Mars Pathfinder: Analysis of Martian Samples by the Alpha Proton X-Ray Spectrometer: Preliminary Results''] Access 2013-04-28.</ref> shows a composition broadly similar to that of Earth, with oxygen and silicon also taking the first and second respective positions.

==Usage==
Silicon is the main material for monocrystalline solar cells, used for [[solar panel]]s. Additionally, it is needed for [[silicone synthesis]] to produce [[synthetic materials]]. 
High-purity silicon (produced by deposition from silanes) is used as a semiconductor in electronics (after being suitably doped). Their are alternatives, such as germanium, though their exact performance characteristics vary and silicon is the obvious choice due to its abundance. 
In the form of stones and bricks, silicates are widely used in construction.

==Open issues==
* How much energy is needed to produce 1 kg of pure silicon for [[electronics]]?
{{science question|How pure does silicon need to be? - [[User:PeterBrett|Peter]]}}

==References==
<references />

[[category:geology]]
[[category:material]]
[[category:recyclable material]]
[[category:chemistry]]

File:Cyclohexasilane cyclohexane cyclohexasiloxane.png

2013-04-28T05:45:35Z

ChristiaanK: Typo

Top: cyclohexasiloxane
Bottom left: cyclohexane
Bottom right: cyclohexasiloxane

Image created with: Avogadro: an open-source molecular builder and visualization tool. Version 1.0.3. [http://avogadro.openmolecules.net/]