Convenient templates for calculating the standard compound-interest factors used in engineering economics and in finance: present value, future value, uniform series of payments, gradient series, and geometric series.  This file has three tabs, one for discrete compounding, one for continuous compounding of discrete cash flows, and one for continuous compounding of continuous cash flows.  Easier to use than a hand-held financial calculator and at a fraction of the cost.

 Spreadsheets for calculating the principal stresses, principal angle, maximum in-plane shear stress, and stresses acting on a plane inclined at an angle with respect to the coordinate axes, all for a state of plane stress.  Faster, easier to use, and less prone to errors than using your calculator—with the spreadsheet you never have to re-enter your data and formulas to double-check your answer.

 WinTri is a standalone computer program (not a spreadsheet) for the reduction of data arising from trilateration surveys; in particular, WinTri calculates the coordinates of stations.  The program is general in that it will handle any control figure that a user might specify.  Data validation is a key feature of the program.  Input data from surveys are extensively checked for errors, and warning messages are displayed on the screen when an error is encountered.  In calculating results, WinTri employs least-squares adjustment.  

WinTri Help screens provide complete, annotated examples of all required input files.  Sufficient explanation is given so that someone who has never used the program before can prepare all input data solely by studying the Help screens.

In addition to the executable module that can be installed and run on the user's computer, the source code, consisting of about 5,000 statements in Visual Basic 6.0, is provided in case the user wants to customize the program to meet special needs.

Download and Installation:  Note that this download is a standalone program not an Excel spreadsheet.  After you download the file, "WinTri.zip," you need to unzip it to a folder which you should set up for this program. After unzipping the files, click on setup.exe and follow the instructions on the screen to install the program on your computer. 

You may get a warning from your browser stating that the file is an exe file and asking if you want to continue.  The file is safe and does not contain any viruses.

This is a pdf version of the book, "Biological Wastewater Treatment Process Design Calculations", which includes information about Activated Sludge, MBBR, and MBR wastewater treatment processes and example calculations.