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Topic: Measuring Wetness/Spotting/Filming  (Read 4277 times)

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Offline Medwell

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Measuring Wetness/Spotting/Filming
« on: May 24, 2011, 04:24:27 PM »
Hi everyone,

First of all, I'm not sure if this is considered "analytical chemistry" as I have not yet taken a course in this area. Feel free to move this to a more appropriate forum, if necessary.

Anyways, I was wondering if anyone knew of any test methods to quantitatively measure any of the following three things:

(Note: These aren't theoretical questions, I am looking for tangible laboratory solutions to these problems)

Wetness
Suppose you have a collection of several identical objects with different amounts of water on them - how could you quantitatively evaluate the amount of water on each?

Spotting
Suppose you have a collection of several identical, uniformly colored objects. They are subjected to a process in which they develop varying amounts of "spots" of another color on them - how could you quantitatively evaluate the spotting on each?

Filming
Suppose you have a collection of several identical, uniformly colored objects. They are subjected to a process in which they develop varying levels of a coating "film" how could you quantitatively evaluate the filming on each?

Thanks in advance!

Offline enahs

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Re: Measuring Wetness/Spotting/Filming
« Reply #1 on: May 24, 2011, 04:27:23 PM »
It depends on what you are starting with.

The wetness one is the easiest, as you can measure the starting mass and remove the water by heat/and or vacuum and measure after, and see how much water was removed.

The other, it depends on so much more.

Offline rucik5

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Re: Measuring Wetness/Spotting/Filming
« Reply #2 on: May 24, 2011, 05:11:44 PM »
It's quite hard for me to approach this problem, since I don't know anything about the 'objects' themselves.
-If you put your sample into a beaker of acetonitrile (10ml) stirr, all the water dissolves and distributes evenly. Then, maybe you could use Karl-Fischer water titration test to quantify it? You put a known amount of liquid into the sampler and get your water content-hence concentration of water in solvent. Would have to check how wet acetonitrile is wet to start with and how quick does it absorb moisture from the air. If not, then use mass: maybe oven--desiccator--vacuum or microwave drying?

-I'm not sure about the spots. Would making a table of, for example: average number of spots A per 1mm^2 etc... be any useful? That would probably introduce a substantial amount of error though. Size of the spots could be important as well, patterns, shapes.

-Filming...well, it again largely depends what the object is made of, how thick the film would be, what it's made from. Really not sure how could you quantify here.
Don't know if these are 'tangible laboratory solutions', but anyway ;) Good luck!

Offline Medwell

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Re: Measuring Wetness/Spotting/Filming
« Reply #3 on: May 25, 2011, 11:19:51 AM »
Thanks to those who replied!

I'm looking into measuring the water by weight, as enahs suggested.

rucik5 (and anyone else reading this), the objects are approximately the size of a fist. Also, the size of the spots do matter (as well as the number); the shapes and patterns, not so much. Finally, I'm looking to minimize the amount of human interpretation involved in evaluating these quantities, so I'd rather if the measurement was done by a machine (i.e. weighing something with a scale rather than judging how heavy it feels).

I really appreciate your input, though!

Offline Stepan

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Re: Measuring Wetness/Spotting/Filming
« Reply #4 on: May 25, 2011, 06:48:50 PM »
Just a few ideas:

Spotting - if colour of the spot is different from background, you can quantify total area of the spots by reflective spectroscopy. 

Filming - depends what what are materials of the object and film. For micron thickness - google for "coating measurements". Automotive industry uses 100's different instruments. If the film is 100's microns of more and quite different from the object, you can try to measure mechanical properties like hardness, or electrical like conductivity of the film, or spectral if the film is coloured

 

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