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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.
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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.
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Tech Corner |
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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. |
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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. |
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Regards,
Carl Clegg
Director of Sales
Phone 973-448-0305
www.ramehart.com
Contact us |
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