Windmill Software Ltd
Data Acquisition Intelligence

October 2007

The Newsletter for PC-Based Data Acquisition and Control
Issue 111       October 2007
--------------------ISSN 1472-0221----------------------

Welcome to October's issue of Monitor.  I hope you enjoy 
the newsletter but should you wish to cancel your 
subscription you can do so at

* Windmill News: Windmill helps radioactive research
* Excel Corner: Reading X and Y values off Excel Charts
* DAQ News Roundup

Windmill News: Windmill helps radioactive research

Scientists are investigating the flow of radioactive 
material through the Yucca Mountain in Nevada.  To date 
measurements and models have assumed a classical, 
steady-state diffusion.  The researchers wanted to test 
if this was an accurate assumption. 

As part of their experiments they took borehole samples, 
exposed one face of the rock sample to water or tracer 
solution and monitored the liquid uptake over time.  
Core samples of varying height to diameter ratios were 
used to investigate the shape effect. 

They hung the rock sample from a bottom-weighing 
analytical balance to measure the weight change during 
liquid imbibition.  To regularly save the readings to 
computer disk, they downloaded the free Windmill 
from the Windmill web site.

Windmill logged balance readings and to the computer at 
selected time intervals, starting with every second and 
increasing the interval as time went on.  

The Windmill software helped show that the steady-state 
diffusion assumed by previous models cannot be applied 
to the Yucca mountain. 

Yucca mountain is the site of a proposed storage 
facility for radioactive waste.

Further reading: 

Q  Hu, R P Ewing, L Tomutsa and M J Singleton. 
Pore Connectivity, Episodic Flow, and 
Unsaturated Diffusion in Fractured Tuff

More Windmill application stories are at

Excel Corner: Reading X and Y values off Excel Charts

This month we were asked how to obtain the Y value on 
an Excel XY scatter chart, given that the corresponding 
X value was known.  There are three approaches to this.  
The easiest is to use an Excel add-in that has been 
created especially to do this. The second way is to 
generate an equation which accurately describes your 
data, and use that to calculate your values.  Thirdly 
you may be able to use Excel's built in functions to 
calculate the values.

1. Using an Excel Add-In
   An Excel add-in contains code that adds extra 
   features to Excel. Excel is shipped with a variety 
   of add-ins, and there are many third-party add-ins 
   available.  One which solves our problem is provided 
   by Tushar Mehta at

   This creates a dialogue box which when you enter an 
   X value tells you the corresponding Y value, and 
   vice versa.  It also draws dotted horizontal and 
   vertical lines to the Y and X axes from the 
   specified point.

   Another add-in is provided by Advanced Systems 
   Design and Development at
   This provides functions to interpolate, extrapolate 
   and curve fit data rapidly.  Use the Interpolate 
   function to find the Y value at a given X value.

2. Generating an Equation from your XY Scatter Chart
   On your XY Scatter chart insert a trendline that 
   fits your data.  Right-click the data series and 
   select Add Trendline. Click the options tab and 
   choose to display both the equation and the 
   R-squared value on the chart.  The R-squared value 
   shows how closely your data fits the equation.  A 
   value of 1 indicates an exact fit.  Values far 
   away from 1 indicate that your calculations 
   won't be accurate and you should try another 

   Copy the right-hand part of the equation into a 
   cell, replacing the x with a reference to the cell 
   holding your known X value. For example, for a linear 
   trendline the equation Excel displays might be 
   y = 1.97x + 0.1.  If your known X value was in 
   cell H8, you would enter: 

3. Using Excel's Functions
   Excel has a couple of built in functions which you 
   can use to return Y values.
   - For a linear trendline use TREND()
   - For an exponential trendline use GROWTH()

Which is the best method to use? I've found that using 
one of the add-ins gives the best results. 

For more on data acquisition and control using Excel see

DAQ News Roundup

Welcome to our roundup of the data acquisition and 
control news.  If you would like to receive more 
timely DAQ news updates then grab our RSS newsfeed 
at  Read for notes
on how to display the news on your own web site, 
read it via e-mail, mobile phone or a newsfeed viewer.

Smart sheets let gadgets talk through their feet
   Flexible, electronic sheets could be embedded in 
   tables, walls and floors, allowing devices 
   anywhere in the home to communicate.  Plastic 
   transistors and copper wires that snake through 
   the sheets allow gadgets placed on them to form 
   spontaneous connections and swap data.
   Source: New Scientist

New Quantum Dot Transistor Counts Individual Photons
   A transistor containing quantum dots that can 
   count individual photons (the smallest particles 
   of light) has been designed and demonstrated at 
   the National Institute of Standards and Technology.   
   The semiconductor device could be integrated 
   easily into electronics and may be able to operate 
   at higher temperatures than other single-photon detectors.
   Source: National Institute of Standards and Technology

Microwaves offer fat chance to probe supermarket food
   Microwaves used for zapping instant meals can also 
   be used to determine the fat and salt content of 
   supermarket food, according to research carried 
   out at two Manchester universities. Constant real-time 
   monitoring by the microwave sensors during the 
   production process could help reduce waste, maximise 
   yield, reduce laboratory testing and save energy.
   Source: Manchester University

Proximity Sensor Market in North America Being Won by European Vendors
   The North American market for proximity sensors 
   has increased at a moderate single-digit average 
   annual growth rate over the last 15 years. However, 
   during the same period, two European vendors have 
   each achieved approximately double the annual market 
   growth rate, and are now the leading suppliers 
   in the market.
   Source: VDC

* Copyright Windmill Software Ltd
* Reprinting permitted with this notice included
* For more articles see

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Windmill Software Ltd, PO Box 58, North District Office,
Manchester, M8 8QR, UK
Telephone: +44 (0)161 833 2782
Facsimile: +44 (0)161 833 2190
E-mail: [email protected]

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