MECA-OM Images - Page 9

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LWS Author Profile Page

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Reply: 161

PostPosted: August 12, 2008 7:22 AM 

Hi Brian

Re the effects of the landing thrusters I'm not thinking of NH3 or anything else added to the soil being sampled. I'm thinking of soil surface material being modified or blown away by the thrusters. It was very clear that the thrusters moved some rocks a considerable distance and that the affected surface was discoloured. There well might have been some non physical, chemical or biochemical effect that we will never know about because there is no control treatment.

Do we know how the soil outside the thruster affected area behaves? Does it have more or less perchlorate? Is it more or less Cohesive? etc. etc.


brian Author Profile Page

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Reply: 162

PostPosted: August 12, 2008 8:25 AM 

G'day Wimstom.
Emily Lakdawalla did an entry on this concern last year. The link is below.

LWS Author Profile Page

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Reply: 163

PostPosted: August 12, 2008 10:50 AM 

Hi Brian

Great Article!! Thanks!


danajohnson Author Profile Page

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Reply: 164

PostPosted: August 12, 2008 3:50 PM 

Horton, at your #153 entry, with the sol75 assembly you have on Flickr, I saw some odd details, and was hoping someone could help me catch up a little. I quickly took a few of the items, for better ID and a process confusion I have.
As a silicone substrate this has some reflectivity, but is this a 'glass' silicone, or a less dense and reflective surface? I see here a double, with another not yet loaded to my photo host, and this first is a crystal with a flat breakaway platy surface it has been embedded. These are a real treat for anyone who has experience with microscopy, as a 'mess' is what normal viewing provides.
5x size, a very quick processed set of items. Something better later.

Altered in various reductions to try to see better edges, but that's all I get.

Another reflection item. Stereo benefits. 5X.

Altered similar to above to reduce glare and color saturation.

Reduced nearly 35 and 43 points in color saturation, horton. That's a lotta hortacolor!!

hortonheardawho Author Profile Page

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Reply: 165

PostPosted: August 13, 2008 12:59 PM 

sol 77 OM pan:

with links to sol 4 - 77 changes.

This is the very first cell imaged on sol 4 with "droplet like feature".

Follow the links to a 4x ( OK, don't ) crop of the droplet aminated, and read the image comments. ( Or not )

Either this is the first interplanetary practical joke -- or it's a monumental Martian discovery. Since the Phoenix team has not highlighted this image, I am guessing that it is the former.

hortonheardawho Author Profile Page

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Reply: 166

PostPosted: August 13, 2008 2:27 PM 

Sol 73-77 OM pan animation:

Still no AFM images.

I hope that the 73 is NOT a "before sampling" image. If so, I am totally depressed that we will ever sort out what is Martian and what is not.

I was sort'a hoping the blob with the tail was the target -- but it was there also on sol 73.

In fact, a lot of stuff seems to have moved around in 4 sols.

So much for trapping stuff in pits and on poles.

LWS Author Profile Page

Posts: 3062

Reply: 167

PostPosted: August 13, 2008 3:56 PM 

Hi Hort

I was just going to put up my composites of the sol 77 OMs when I saw yours. Thanks very much for the sol 73/77 comparison. It raises some very interesting questions about the OM procedures. here's the data from the mouse overs and the rotation table thats linked to the OM substrates

Sol 73 10680 48911 OM49 Nanobucket substrate
Sol 77 10680 48711 OM49 Nanobucket substrate

The 10680 is the rotational position and 48911/48711 is the focus position.

There is a possibility that the only change was in the focus position. If so it raises some questions about the OM process.

Do the images released on the different sols represent new samples?

If so, are they placed on top of old samples. Since this does not seem likely it seems that the new releases in some cases are only reimaging samples that have already been made some time ago.

If this is so, it would be of great interest if they would indicate when the samples were taken, from which soil area and trench, etc.

The labelling of these images leave a lot to be desired.

That there are so many points of correspondance between the spots on both sols suggest that either they are before and after images or that samples are being placed on substrates that had already been populated earlier.

It is more reasonable to consider that it is the latter case.

If the sol 73 and sol 77 images represent before and after images they would truly be a nightmare for any study of the images. I therefore believe that they are not before and after images, just reimaging at a different focus.

If this is so, and the focal length of the OM is so precise, then several reimagings at different focal lengths for most images seem to be in order and we are going to have to be looking at several such images over the next several weeks.

have to run


LWS Author Profile Page

Posts: 3062

Reply: 168

PostPosted: August 13, 2008 5:33 PM 

Hi Hort et Al

Good news from Ustrax on the UMSF. It looks like AFM Mars images will be posted soon. See


LWS Author Profile Page

Posts: 3062

Reply: 169

PostPosted: August 13, 2008 10:25 PM 

Hi Hort et al

To follow up on my #168. Here's an enhanced version of what is possibly the OM image from which the AFM referenced above was taken.

The image was from sol 68 and was on a nanobucket substrate (OM67). I converted it to 12 bit, magnified it by 2 and sharpened and lightened it in Photoshop.

There are many small spheres of roughly 1 uM in diameter that are in the 5 uM buckets on the left side of the image. Many of those spheres seem to be also present (usually covered)in the irregularly shaped ubiquitous globs that are also captured by the strong and weak magnets. I don't see any particular particle that stands out as there are so many. There are also a number of Hort's transparent/translucent blobs but these seem to be a bit bigger than 1 uM.



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Reply: 170

PostPosted: August 13, 2008 11:40 PM 

re 166, I don't think it is a surprise that some particles would move around. The substrate wheel revolves, and when new samples are added to the wheel the existing, loaded substrates would get a real shakeup. Perhaps this is a good thing since this will give new material/aspects to image in filled cells following a load sequence.

165 looks like a clean before shot. Couldn't find the 4x link you refer to?

hortonheardawho Author Profile Page

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Reply: 171

PostPosted: August 14, 2008 6:51 AM 


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Reply: 172

PostPosted: August 14, 2008 9:07 AM 

On Sol 4 they imaged some cells from the calibration set and this single cell from set 3. So there must have been something special about ot that they wanted to get a calibration shot of. From this act I would guess that they knew about the deformity in the substrate, deliberate or accidental in manufacture. It is OM 24 silicone.

The animation doesn't seem to show anything other than a lighting change. Probaby a pre loading shot of the cell, maybe, perhaps.

hortonheardawho Author Profile Page

Posts: 3465

Reply: 173

PostPosted: August 14, 2008 11:53 AM 

Er, you can't "see" the distorted continuation of the bright lines behind the perfectly round circle and the corresponding brightening of the lines when the lighting direction changed??

Guess not.

A release of the pre flight and cruise OM images of all the cells would settle the matter.

Er, speaking of which:

sol 78 1/2 frame OM - position 2411 ( Silicone ):

According to the sample wheel table this was also imaged on sol 4. Er, can anyone find the sol 4 image?

While I was looking I discovered that I hadn't posted this sol 67 OM montage:

It is interesting in that I tried a simple visual translation alignment of the images.

The idea was to eliminate the mucking around and bit fiddling intrinsic to all panorama software.

This one, according to the table, is also a Silicone substrate - not imaged before sol 30.

I will add the substrate information to any new OM images.


Posts: 1

Reply: 174

PostPosted: August 14, 2008 8:09 PM 

Hort, re: 171. Last year I spilled some beer on my garage floor. It all evaporated except one drop that landed on a small oil spot. It was a spherical droplet that persisted for HOURS. It was gone when I checked the next day. Is the droplet you posted an anomaly? When it DOES evaporate, will there be a residue?


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Reply: 175

PostPosted: August 14, 2008 8:15 PM 

John, is it light beer? If it is no.



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Reply: 176

PostPosted: August 14, 2008 10:10 PM 

Actually, Fred, I am quite serious about the post. How does surface tension affect evaporation? Explain it to me, please.


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Reply: 177

PostPosted: August 14, 2008 10:19 PM 

Well John,

I do know a little about evaporation I suppose. Surface tension has nothing to do with it.



Posts: 708

Reply: 178

PostPosted: August 14, 2008 11:51 PM 

Hi John,
Oil will from a coating over the droplet surface and slow down any evapourative processes. So yes surface tension in this scenario is a contributing factor.

In the OM I think we just have a semi transparent blob of silicon. There is also a spread out coating very evident in 165. Not even a sniff of manure from the pony.


Posts: 638

Reply: 179

PostPosted: August 15, 2008 12:08 AM 


All mediums have a specific surface tension. To change that you would need to add an agent, like oil. Now you can have several agents but without knowing the agent you are speculating. If it is cloudy it is cooler too.



Posts: 57

Reply: 180

PostPosted: August 16, 2008 12:02 AM 

Re your comment in reply 177.

I stand to be corrected but I think you could be a bit off the mark in your statement that 'Surface tension has nothing to do with it'.

The classical picture of evaporation is still down to the statisical distribution of energy amongst the molecules of the fluids concerned.

As I picked it up at college ( over 30 years ago hence subject to error never having had to apply or use this since, being an Old Electrical engineer who spent his career in communications technology).

At any given temperature a proportion of the molecules have a certain energy and hence velocity which allow them to escape from the liquid or solid. Having 'achieved' the speed, velocity becomes relevant since direction determines wether the molecule escapes from the liquid or not. To physically escape through the liquid/gas barrier and enter the gas region the molecule must have enough energy to overcome both the attractive forces within the liquid region and enter the gaseous region. Attractive forces within the solid or liquid region are balanced by the lack of attraction between gaseous molecules (at least below 250 bar or so in the case of O2 and N2. Surface tension ie attractive force between the molecules of the liquid therefore represents a barrier which must be overcome and the stronger it is the smaller the rate at which molecules can escape to the gaseous region.

The rate of evaporation is also dependent on the pressure of the gas, at lower pressure more molecules can enter the gas region, but as the saturation of the gas increases a balance arises whereby the rate of escaping molecules equates with the portion of those in the gas region capable of re-entering the liquid/solid region. In both leaving or re-entering the liquid or solid region the molecule must penetrate the surface tension barrier. As a result higher surface tension slows the rate of evaporation but also increases the saturation value of the gas phase.

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