CSC Scientific Blog

A blog about test equipment

CSC Scientific Blog

How Wide Is The Moisture Measurement World?

Posted by Art Gatenby on May 13, 2014 6:26:00 PM

At one end of the spectrum of the moisture world is the classic Speedy Moisture Tester where you use the reaction of water with calcium carbide to cause a mini explosion resulting in a moisture measurement reading. This method is used frequently for soils, concrete, and other like materials.

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Topics: Moisture Sorption Isotherm, Moisture Analysis, Water Activity, Karl Fischer, Loss-On-Drying

Moisture Content and Water Activity - What Are They?

Posted by Art Gatenby on May 30, 2013 1:23:00 PM

Many accessing our web site ask questions such as:

  • “How does water content affect water activity?”

  • "How is water activity different from water content?”

  • ”Can I convert from moisture to water activity?”

I previously commented on water activity and now hope to clarify the differences between water activity and moisture content. Given that both of these measurements deal with water connected to a material, we must first understand of water content in a product.

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Topics: Moisture Sorption Isotherm, Moisture Analysis, Water Activity, moisture content, moisture measurement, water activity measurement, water content measurement

Moisture Content - Water Activity – Are They the Same Thing?

Posted by Art Gatenby on Mar 6, 2012 4:19:00 PM

The other day, I woke up with a lingering quandary: Are the concepts of

Moisture Content and Water Activity the same thing?

As usual, I’ve decided to take on the task of clarifying the difference.  I hope I pull it off.

From the perspective of someone who supplies instruments that measure moisture content, water activity has not been a primary consideration.  However, I believe that comparison and contrast of these important concepts will be useful.

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Topics: Moisture Sorption Isotherm, Infrared Moisture, Moisture Analysis, Water Activity, Moisture Testing

Loss-on Drying and Other Moisture Mysteries - Part V: Drying

Posted by Art Gatenby on Jun 15, 2011 12:55:00 PM

Just over six months ago, I began this journey explaining the simplest approach to measuring or determining moisture: Loss-on Drying. Little did I know how involved and esoteric it would become.

This voyage has taken me down mysterious paths through spooky theories, back to age-old chemistry concepts and into the vagaries of thermodynamics related to evaporation, vapor pressure, bound water and water activity. I have come full-circle; back to explaining Loss-on Drying -- a form of drying that I had assumed would be the simplest of all.

I thought the first four topics [evaporation, vapor pressure, bound moisture, water activity] were tough, complex, confounding and less-than-obvious. Drying -- defined as “the mass-transfer process of removing water (or other solute) by evaporation from a solid, semi solid or liquid” -- seemed easy.

As is often the case, reality makes “easy” a non-operative word. Such has turned out to be so with respect to the issue of drying.

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Topics: Free Moisture, Moisture Sorption Isotherm, Moisture Analysis, Moisture Testing, Loss-On-Drying

Loss-On-Drying Moisture Analysis and Other Moisture Mysteries Part IV: Water Activity

Posted by Art Gatenby on Mar 31, 2011 3:39:00 PM

Loss-On-Drying moisture analysis seemed like a simple process until, in a state of naïve bliss, I promised to look at evaporation, vapor pressure and bound water. While I was otherwise occupied with these realities, I offered to enter the world of witchcraft and folklore; water activity.

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Topics: Bound Moisture, Moisture Sorption Isotherm, Moisture Analysis, Water Activity, Loss-On-Drying

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