Mathcad Plus

Taking the upward direction as positive, when both Fy < 0 and Fs<0, represents a co-current downflow operation, if Fs < 0, but Fy > 0 means a counter-current operation. The rest of the equation defining the system can be seen in Berty (1997). Integration was done by the Romberg method as is used in Mathcad PLUS 6 (1996) software. 

Mathcad Plus 6, of MathSoft, Inc. was used) Independent Variables on log scale... 

V. F. Ochkov, MathCAD PLUS 6.0 for Students and Engineers (Computer, Moscow, 1996)... 

Multiple regression analysis can be executed by various programs. The one shown in the Appendix is from Mathcad 6 Plus, the regress method. Taking the log of the rates first and averaging later gives somewhat different result. 

Before closing this section it should be mentioned that most of the methods discussed above can be solved using commercially available programs such as symbolic computation (Mathematica, Maple, or Mathcad 3.0), equation solvers (TK Solver Plus or Mathcad 3.0), spreadsheets (e.g., Lotus 123, Quattro Pro, Microsoft Excel, or Wingz), simulators (Extend or Stella), or Microsoft FORTRAN 5.0. For example, one can introduce the idea of molecular mechanics on model systems using a spreadsheet. Actual applications of molecular mechanics are much better carried out on a software package designed for that purpose, however. 

Nonetheless, this numerical problem can be accomplished on a spreadsheet, Stella, TK Solver Plus, Mathcad, etc. 

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