Revision History for OF 2001-0045

by Larry G. Mastin

A simple calculator of ballistic trajectories for blocks ejected during volcanic eruptions

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Report Version 1.2 ... (November 2009)
	1)   Report version 1.2 is identical to report version 1.1 except for the correction of a typo in eq. 14
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Program Version 1.2 … (June 2002) 
1)	Corrects errors from version 1.0.0 in the calculation of block size and frontal area for cubes.  Version 1.0.0 incorrectly calculated block volume as the cube of the half-width of the block, rather than the cube of the block width.  In addition, the frontal area of cubes was incorrectly calculated as the frontal area of a sphere. Thanks to Mark Cranness of New Zealand for pointing out these bugs.
2)	Modifies radio buttons for block shape so that they are now undimmed when the “constant drag coefficient” radio button is chosen.  Users can now specify a constant drag coefficient and choose different block shapes.

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Program Version 1.3 … (March 2004)
1)	Corrects a glitch that prevents trajectories from being plotted when the landing point is below the takeoff point
2)	Added a radio button that allows users to specify the block’s frontal area rather than its diameter or width.  When a radio button is clicked, the number in the text box is converted from frontal area to diameter or width (or vice versa) for the specified block geometry.
3)	Added gridlines to the plot and a legend indicating which line colors correspond to which model runs.
4)	Corrected a glitch in which the incorrect temperature at the takeoff point was written to the output file.
5)	Added temperature and air density to the list of parameters written to output file.
6)	Added a radio button allowing users to plot trajectories for a sphere, high cube, low cube, and shell in rapid succession.  Using this option, the program writes output to for all four trajectories to a single output file.
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Program Version 1.4 ... (February 2008)
1)  Corrected a glitch that caused the air density at the starting point to be slightly overestimated at high altitude.


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