Download Rational Equation Calculator (Excel file)
Download Rational Equation Calculator (Executable file)
The Rational equation is the simplest method to determine peak discharge from drainage basin runoff.
Rational Equation:  Q=ciA The Rational equation requires the following units: Q = Peak discharge, cubic meter/second c = Rational method runoff coefficient i = Rainfall intensity, mm/hour A = Drainage area, ha
The Rational method runoff coefficient (c) is a function of the landuse, soil type and drainage basin slope. (Check Table here for calculating c, Rational method runoff coefficient) Source: Batelaan and Woldeamlak  (2007)

Calculator for Sun Earth Angles
Very User friendly Program. This program can calculate all the solar earth angles by taking some input parameters.

Download link

User has to give input parameter as 

1. n, i.e. number of days starting from January 1; 
2. phi, Latitude Angle; 
3. Solar Time; Gamma, 
4. Surface Azimuth Angle, 
5. Reflectivity of ground; 
6. Turbidity factor of surface.            

Output parameters include (19 parameters)

1. Declination Angle, 
2. Hour Angle, 
3. Zenith Angle, 
4. Solar Azimuth Angle, 
5. Iext (Extra Terrestrial Radiation), 
6. In (Normal Irrad in Terrestrial region), 
7. Incident Angle, 
8. Flux of Beam Radiation on horizontal surface(Ihb), 
9. Flux of Diffuse radiation on horizontal surface(Id), 
10. Flux of Beam Radiation on inclined surface (Ib'), 
11. Amount of diffuse radiation available on inclined surface (Id'), 
12. Reflected component of Total solar radiation on inclined surface (IR'), 
13. Total solar radiation falling on inclined surface of absorber plate at solar noon (Ii), 
14. Ratio of apparent width of the horizontal absorber plate intercepted by sunrays to apparent width of the inclined absorber plate intercepted by sunrays (Wh / Wi), 
15. Ratio of total radiation flux on inclined surface to global radiation flux on horizontal surface (Ii / Igh), 
16. Ratio of intensity of beam radiation on horizontal surface to beam radiation flux on normal surface (Ihb / In), 
17. Ratio of beam radiation flux on inclined surface to beam radiation flux on normal surface (Ib' / In), 
18. Optimum angle of the reflector mirror with vertical for horizontally placed cooker (λ), 
19. Optimum angle of the reflector mirror with horizontal for optimally inclined cooker (ψ).

Download Colour Picker

Colour Picker is a portable program for Windows Platform. Easy-to-use and highly functional tool for anyone working with color. 
Colour Picker is a program for web designers and programmers. It identifies and represents colors in hex colour code format and RGB format. 

Two features are provided in the program:

1. Select the eyedropper control, and move the cursor to any location on the screen. The hex color code for the selected color will be automatically displayed and can be copied. The RGB values will be displayed in the status bar.

2. Select the colour button to open the colour palette to select a particular colour and get the Hex code and RGB values.