If you're having trouble viewing this email, you may see it online.

October 2006

Creating a Movie using DROPimage Advanced
DROPimage Advanced uses the Axisymmetric Drop Shape Analysis (ADSA) method for measuring interfacial and surface tensions. Data collected using this method can be particularly compelling when using dynamic volumes. For this type of study we start with a small pendant drop and add volume over time. This is best accomplished using the ramé-hart Automated Dispensing System, but -- with practice -- can also be done with some degree of precision using our manual microsyringe.

To watch a movie created by DROPimage of a dynamic pendant drop, click here: http://www.ramehart.com/goniometers/diadv.htm (or copy and paste the URL into your browser). This particular video is also posted on youtube.com and can be accessed directly here: http://www.youtube.com/watch?v=Pi5CD-GEwJ0  or click the image below.

We created a tutorial for making the video which is available on request. So, if you are currently using DROPimage Advanced and would like a copy, please contact us. The tutorial walks through the steps for creating an experiment which will capture 100 frames over about 20 seconds. The images are captured by DROPimage Advanced and can be replayed using DROPimage or imported into other programs, such as Windows Movie Maker. The initial volume of deionized water is 5uL and is gradually increased 15uL, then reduced back to 5uL.

There are many applications that benefit from a dynamic surface tension study using the generic method outlined above. The study of free surface flows of product for packaging in the food industry is one example. In addition, film and coating processes, paint drying, and the dispensing of ink during the ink jet printing process, are all examples of commercial applications where understanding both surface tension and surface energy are important.

DROPimage Advanced calculates surface tension by capturing the contour of the two-dimensional profile using an edge tracing algorithm. The profile is then analyzed using a method based on a least squares fit to theoretical profiles produced by a numerical integration of the Young-Laplace equation. This method has been published in J. Colloid Interface Science and has been developed for us by Dr. F. K. Hansen.

Retirement of a Legacy
This month we have retired our classic Model 100-00 Manual Contact Angle Goniometer based on the original NRL design by Dr. William Zisman. ramé-hart has been producing this classic tool for the past 40 years. We have sold thousands and many are still in daily use. During the past decade the manual tool has become less relevant as our software-driven tools have become more robust, less costly, and more accurate. We currently offer a fully-featured camera-based Model 120-F0 with DROPimage CA at a price lower than what the Model 100-00 last sold at. Additionally, long-time instrument craftsman Rolf Pfeil is retiring and we no longer have the resources to continue to manufacture the labor-intensive microscope. We will continue to support the classic Model 100 and we will carry spare parts for years to come. Additionally, we have an imaging upgrade kit for both the Model 100 and its smaller sibling, Model 50. For more information on these imaging upgrade kits, please refer to our October 2005 Newsletter here: http://www.ramehart.com/goniometers/newsletters/2005-10_news.htm The imaging upgrade kit includes the F1-series digital camera, software, PC and LCD, and everything else necessary to convert a legacy Model 100 to a current-generation software-driven tool.
Tech Corner
One of the most aggravating problems with Windows is the constant possibility that adding a new program or update or service pack or patch can affect -- sometimes adversely -- system components or other device drivers and applications which, prior to the change, were working properly. We run into these problems as well. Our software-based tools require many system components to be installed and working properly for the entire system to be functional. At times we have customers whose systems become inoperable due to software upgrades and patches as well as malware such as adware and viruses. Suddenly the system stops working or performance may become seriously degraded. One tool that we find very useful for undoing problems like this is Windows System Restore. This utility which was introduced with Windows XP (not available in Windows 2000) creates system restore points on a periodic basis and anytime significant changes are made to your system. At any time (unless System Restore has been manually disabled) you can roll your system back to an earlier date. No data or user-produced files will be deleted or affected by this procedure. Only Windows system files, registry settings, and driver versions are affected. As a result, if you restore past a software upgrade or installation, those changes will be undone -- and in most cases, your system will become operable again.

To access System Restore in Windows XP, click on Start > Help and Support. Then click on System Restore. When the wizard starts, choose "Restore my computer to an earlier time" and next. You will then be presented with a calendar. The bold dates are those you can restore to. In general, you want to pick a date when the system was running well. Don't worry, you can always undo the restore. One you click Next, Windows will restore the system files and registry to that point and reboot your system.

Another common problem is insufficient privileges. In order for Windows and DROPimage to work properly, the user should have administrative rights (for the local machine). Should you have any questions or need help troubleshooting a problem with a goniometer PC, please don't hesitate to call on us.

We appreciate your continued business and look forward to assisting you with your contact angle measurement needs now or in the future. Remember, spare parts are available on our website at: http://www.ramehart.com/shop/. If you have any feedback, we welcome it.


Carl Clegg
Director of Sales
Phone 973-448-0305
Contact us