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*****************************  fluids.sh  ******************************
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                                                            May 15. 2013
CONTENTS:

- CONCEPT
- IMPORTANT NOTE!
- INSTALLATION
- USAGE
- CITATION
- HISTORY

									
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CONCEPT

fluid.sh is a shell script which utilized 'wget' to acquire fluid properties 
from the NIST Chemistry WebBook (http://webbook.nist.gov/chemistry/) in a 
format suitable for further processing with shell scripts or e.g. xmgrace.
It supports the full functionality provided by the website!

The script takes the same input as command line arguments you need to
enter on the web forms. It produces a ASCII text file containing the
respective data points in columns headed by a well readable description.
The advantage is that you do not need to "click" through three web pages
and export the result - you can do it with _one_ command in the shell!
This makes it possible to introduce it in shell scripts to automatize the
analysis of other data, to compare or just to save time.


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IMPORTANT NOTE!

Every usage of 'fluids.sh' produces traffic on the NIST web server.
So please be careful, especially if you add a call to 'fluids.sh' in a 
script (even in a loop!).

Till yet this service is provided from NIST for free. So please be fair!
If you need to access this data on a daily basis or within a commercial background,
you should consider to buy 'NIST Reference Fluid Thermodynamic and Transport 
Properties Database (REFPROP)' [http://www.nist.gov/srd/nist23.cfm]!

									
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INSTALLATION

 0. Requirements:
    
    The script is written to be interpreted with the Bourne shell (sh),
    which is usually available on all Unix/Linux platforms.
    Despite the standard command line tools (cat, tail,...) the only
    dependency is 'wget' to request and retrieve the data from the 
    NIST web server.
    
    
 1. Installation:
    
    Just copy the 'fluids.sh' file in a folder which is included in your
    $PATH or add the folder to the $PATH variable.

									
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USAGE

 0. General:
 
    Just type 'fluids.sh -h' to get the help message.
    You need to specify the substance of interest by an ID. To get a list
    of available substances and the respective ID, type 'fluids.sh -show'.
    For further information about the handling of the units of the input
    and output quantities type 'fluids.sh -units'.
    
    
 1. Example:
 
 	 Calculate an isotherm (-it) of water (-id C7732185) for T/K=725.5
	 from p/MPa=1.0 to 10.0 with p.increment/MPa=0.5 and use SI units:

    fluids.sh -id C7732185 -it -T 725.5 -pl 1.0 -ph 10.0 -i 0.5 -si


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CITATION

Please cite properly!
In general you should cite

  "P.J. Linstrom and W.G. Mallard, Eds., NIST Chemistry WebBook,
   NIST Standard Reference Database Number 69, 
   National Institute of Standards and Technology,
   Gaithersburg MD, 20899, http://webbook.nist.gov, (retrieved <date>)"

for the source.

If you make use of particular data in a publication (paper, thesis,..)
you should have a look at the respective 'NIST Chemistry WebBook/
Fluid properties' [http://webbook.nist.gov/chemistry/] website to refere 
to the individual publication regarding the property of interest.


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HISTORY

1     First non-public release.
1.01  First public release: cleaning up the code.