|
ramé-hart instrument co.
July 2013 Newsletter |
| Temperature Logging and Control |
|
The past few months we've been busy
updating our flagship
DROPimage
Advanced program and expanding and updating our array of modular
accessories. In
May we announced our new
Peltier Environmental Chamber (100-30). In
June we announced our new
Temperature Logger (100-32). This month we are now pleased to
announce an upgrade to our
Temperature Controller (100-50). All of these accessories now sport
a serial interface which permits them to communicate via a USB
connection with our DROPimage software for temperature control and
logging. In the video below (or go to http://youtu.be/0v6_1DGOoLI), we are using DROPimage Advanced v2.7 to demonstrate how temperature control works with our newly updated Temperature Controller (100-50) which in turn is controlling our Environmental Chamber (100-07). We first show you (0:20) how to turn on the Temperature Control feature in DROPimage Advanced. Next we see (0:29) how the current chamber temperature and the set point are displayed on the tool bar along the top of the program interface. We then use the Temperature Control dialog (0:38) to change the set point from 40.0° to 100.0° C. With the temperature increasing, we begin a saved experiment (0:53) that will measure surface tension as a function of time. We then observe graphically (1:47) the expected behavior which is that as the temperature increases, surface tension decreases. The temperature control shown in the video works the same for the Peltier Environmental Chamber (100-30) as it does for the Temperature Controller (100-50). In the case of the Peltier Environmental Chamber (100-30), however, the controllable temperature range is from -50° to 150° C. With the Temperature Controller (100-50), the controllable range is from ambient to 300° C when used with standard Environmental Chamber (100-07). Note that the Temperature Controller (100-50) is also used with the Elevated Temperature Syringe (100-11) and Advanced Chamber with Temperature Control (100-26-T). With the Temperature Logger (100-32), no set point is used as the purpose of this device is to capture the current temperature and then pass it onto DROPimage for logging and reporting purposes. If you have any questions regarding our
new temperature control and logging capabilities, are interested in a
new system or upgrading an existing setup, please
contact us
for answers and more details on our products and the best fit for your
application. |
| Why Does Surface Tension Decrease as Temperature Increases? |
|
If you watched the video from the article
above, you may be wondering: Why does surface tension decrease as the
temperature rises? If you think of a pendant drop of water as having a
very thin elastic skin holding it all together -- which is how it
behaves, this outermost membrane (which is actually made up of water
molecules) is held together by cohesive forces (such as hydrogen
bonding). As the temperature increases, the molecular thermal activity
causes a decrease in these cohesive forces. You could say that the thin
elastic skin is weaker and can be more easily stretched. As the cohesion
decreases and the skin stretches, the surface tension decreases. |
|
Regards,
Carl Clegg |
