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Wikipedia:WikiProject Check Wikipedia

 * WikiProject Check Wikipedia

Copied text attribution

 * Template:Copied
 * Help:Dummy edit

Multiple non-breaking spaces, or tabs
In place to type three non-breaking space as &nbsp ;&nbsp ;&nbsp ;, it is much better to use the pad template to introduce three "em" spaces:

Global cell alignment at the level of a table
In the first line defining the table:

class="wikitable" style="text-align: center" centering all cell contents in the table at a same time

Decimal point alignment
Help:Table

A method to get columns of numbers aligned at the decimal point is as follows:

What it looks like in your browser: 

An alternative, by still using only one cell for each number, i.e. without any split around the decimal point, could also be the following one by adding to each cell the parameters:
 * style="text-align:right; padding-right: 1em;" |

and by varying the padding value "1em" when necessary with an appropriate fraction as for example "1.5em" to increase the right indent in order to correctly align the decimal point.

Calculation of the drilling debris mass
For: Talk:2010 Copiapó mining accident.

Calculation of the volume of drilling debris to be evacuated by the miners themselves.

This is in fact the quarter or the half of the 3000 to 4000 tons erroneously reported in the WikiNews article:

Race to save Chilean miners trapped underground from spiralling into depression continues

"Quotation from WikiNews (as seen on September 4th, 2010)":
 * "But over the weekend, The New York Times reported that the "miners who have astonished the world with their discipline a half-mile underground will have to aid their own escape — clearing 3,000 to 4,000 tons of rock that will fall as the rescue hole is drilled, the engineer in charge of drilling said Sunday ..."

In fact, the miners will have to remove by themselves a total mass of fine rock debris (drilling cuttings) estimated between 700 and 1500 tons considering a borehole diameter of 70 cm or 1 m respectively, with a depth of 688 m and a rock density of 2.7 ton per cubic meter. See the table below for the volume and mass calculations easy to verify.

And it is already a large mass to be continuously evacuated by the miners.

Calculation of the drilling debris mass

PBS
137 mM NaCl, 2.7 mM KCl, 10 mM sodium phosphate dibasic, 2 mM potassium phosphate monobasic and a pH of 7.4

Glycerol use in the laboratory
Glycerol can also serve as thickening substance to increase the viscosity of the fluid of the reference electrode compartment in pH and Eh (redox) electrodes. Gelified pH electrodes may release high concentration of glycerol is solution and affect the solution composition. To minimise the glycerol release, electrodes should not be immersed in solution during a too long period of time.

Onsager reciprocal relations
New table to make here

Alkali-silica reaction equations aligned in a table
See soda lime reactions compared with the alkali-silica reaction équations.

In line equations:


 * reaction 1: SiO2 + NaOH → NaHSiO3


 * reaction 2: NaHSiO3 + Ca(OH)2 → CaSiO3 + H2O + NaOH


 * sum 1 + 2: SiO2 + Ca(OH)2 → CaSiO3 + H2O

Equations aligned by means of a table:


 * {| class="wikitable"| border = 0


 * reaction 1:||  || align = "right" | SiO2 + NaOH    ||   || → ||     || NaHSiO3||   ||(silica dissolution)
 * reaction 2:||  || align = "right" | NaHSiO3 + Ca(OH)2 ||   || → ||   || CaSiO3 + H2O + NaOH ||     ||(C-S-H precipitation)
 * sum (1+2):||  || align = "right" | SiO2 + Ca(OH)2 ||   || → ||   || CaSiO3 + H2O ||     ||(Pozzolanic reaction)
 * }
 * sum (1+2):||  || align = "right" | SiO2 + Ca(OH)2 ||   || → ||   || CaSiO3 + H2O ||     ||(Pozzolanic reaction)
 * }
 * }

Analogy with the soda lime reaction

 * {| class="wikitable"| border = 0


 * reaction 1:||  || align = "right" | CO2 + 2 NaOH   ||   || → ||     || Na2CO3 + H2O||   ||(CO2 trapping by NaOH: high pH)
 * reaction 2:||  || align = "right" | Na2CO3 + Ca(OH)2 ||   || → ||   || CaCO3 + 2 NaOH ||     ||(calcite precipitation and regeneration of NaOH)
 * sum (1+2):||  || align = "right" | CO2 + Ca(OH)2 ||   || → ||   || CaCO3 + H2O ||     ||(global reaction = carbonation reaction catalysed by NaOH)
 * }
 * sum (1+2):||  || align = "right" | CO2 + Ca(OH)2 ||   || → ||   || CaCO3 + H2O ||     ||(global reaction = carbonation reaction catalysed by NaOH)
 * }
 * }

Global warming potential
The global warming potential (GWP) depends on both the efficiency of the molecule as a greenhouse gas and its atmospheric lifetime. GWP is measured relative to the same mass of and evaluated for a specific timescale. Thus, if a gas has a high GWP on a short time scale (say 20 years) but has only a short lifetime, it will have a large GWP on a 20 year scale but a small one on a 100 year scale. Conversely, if a molecule has a longer atmospheric lifetime than CO2 its GWP will increase with the timescale considered.

Carbon dioxide has a variable atmospheric lifetime, and cannot be specified precisely. Recent work indicates that recovery from a large input of atmospheric from burning fossil fuels will result in an effective lifetime of tens of thousands of years. Carbon dioxide is defined to have a GWP of 1 over all time periods.

Methane has an atmospheric lifetime of 12 ± 3 years and a GWP of 72 over 20 years, 25 over 100 years and 7.6 over 500 years. The decrease in GWP at longer times is because methane is degraded to water and CO2 through chemical reactions in the atmosphere.


 * Nitrous oxide has an atmospheric lifetime of 114 years and a GWP of 289 over 20 years, 298 over 100 years and 153 over 500 years.
 * CFC-12 has an atmospheric lifetime of 100 years and a GWP of 11000 over 20 years, 10900 over 100 years and 5200 over 500 years.
 * HCFC-22 has an atmospheric lifetime of 12 years and a GWP of 5160 over 20 years, 1810 over 100 years and 549 over 500 years.
 * Tetrafluoromethane has an atmospheric lifetime of 50,000 years and a GWP of 5210 over 20 years, 7390 over 100 years and 11200 over 500 years.
 * Hexafluoroethane has an atmospheric lifetime of 10,000 years and a GWP of 8630 over 20 years, 12200 over 100 years and 18200 over 500 years.
 * Sulphur hexafluoride has an atmospheric lifetime of 3,200 years and a GWP of 16300 over 20 years, 22800 over 100 years and 32600 over 500 years.
 * Nitrogen trifluoride has an atmospheric lifetime of 740 years and a GWP of 12300 over 20 years, 17200 over 100 years and 20700 over 500 years.

Examples of the atmospheric lifetime and GWP for several greenhouse gases are given in the following table:

The use of CFC-12 (except some essential uses) has been phased out due to its ozone depleting properties. The phasing-out of less active HCFC-compounds will be completed in 2030.

style="text-align: center; width: 200px; height: 200px;" align="center" | align="left" | align="right" | colspan="3" | rowspan="2" |

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