Monday, 27 February 2012

By on February 27th, 2012 in science kits

08:13 – We’re down to a dozen chemicals left to package, after which we’ll be ready to start assembling biology kits. Most of those are obnoxious ones in one way or another, and I always leave those for last. For example, the glycerol and sodium dodecyl sulfate solutions are extremely viscous. We’ll probably package those in wide-mouth bottles rather than standard dropper bottles, simply because it’s so hard to get the chemical into (and then out of) the dropper bottles. Then we have stuff like 6 molar solutions of sodium hydroxide, acetic acid, ammonia, and hydrochloric acid, all of which are extremely corrosive and the last three of which emit noxious and choking fumes.

Speaking of kits, I’m also putting together a list of items to go in the forensics kit. I’d like to include a small amount of concentrated nitric acid, which until recently I thought was illegal to ship in any quantity without paying a hazardous material surcharge. It turns out that I may be able to include 30 mL or less under the section 173.4 small-quantity exemption. So I started checking resistance of various materials to 68% nitric acid. It turns out that polyethylene will probably work just fine, which surprised me.

While I was at it, I decided to check resistance to 98% sulfuric acid, which is used in Marquis reagent and Mandelin reagent (presumptive drug test reagents that are essentially 98% sulfuric acid, with tiny percentages of formaldehyde and ammonium metavanadate present, respectively). To my surprise, it appears that 98% sulfuric acid is even tougher on common plastics than is 68% nitric acid.

I’d package those solutions in 10 mL glass bottles packed inside 50 mL polypropylene centrifuge tubes, but the question is what kind of cap to use on the bottles. One option is a PP cap with a PE liner. I have a sample of that bottle and cap, so I’m going to fill it with Marquis reagent and store it for a couple months inverted inside a centrifuge tube to see what the Marquis reagent does to the cap and liner.


16 Comments and discussion on "Monday, 27 February 2012"

  1. SteveF says:

    Suggestion: Don’t put the vial of acid in a centrifuge tube. That’s 50% wasteful of possible outcomes. If the cap doesn’t leak you know how you can ship, but if it does leak you don’t get any good out of it, merely some negative knowledge.

    Instead, invert the vial over a rope. The rope is holding a cage over a piranha-filled river. The cage holds a politician. If the vial doesn’t leak: good! You know how you can ship the acid. If the vial does leak: good! The piranhas eat the politician. If you kind of forget about your experiment and the politician starves to death: good! You’re still rid of the politician.

  2. Raymond Thompson says:

    The cage holds a politician.

    Seems like a waste of rope, acid and cage along with cruel and unusual punishment for the Piranhas.

    And just for your entertainment here is a composite image I did of a senior HS basketball school player. The image is large and is composed of 11 layers with 11 layer masks added the converted to JPG.

    http://www.raymondthompsonphotography.com/KellieBall.jpg

  3. Chuck Waggoner says:

    Wow! That image is sharp. Only took 45 seconds to download here, but then I have AT&T, so I imagine it is quicker for the rest of you. Any reason you use JPG rather than PNG, Ray? I had always heard that PNG preserved resolution better, but maybe that is not/no longer the case?

    Look at those people in the stands. They sure prove Americans are overweight. Of course, it would be hard to find a sample of Germans at a high school basketball game, because the schools do not sponsor sports — that is all done by sport clubs outside the school system. Which is the way it ought to be here in the US: no sports in schools, aside from exercise in physical education. I push that pretty hard around here, and will be lucky to escape these parts alive.

  4. Miles_Teg says:

    http://www.abc.net.au/news/2012-02-28/costa-allegra-drifting-in-indian-ocean-after-fire/3856158

    Boy, I know which cruise ship company I don’t want to utilise.

  5. OFD says:

    Took about the same amount of time to download here with Fairpoint (formerly Verizon); that is pretty cool, Ray.

    So is it just me or is it the case that female b-ball players and track-and-field girls often have spectacular legs but no racks at all?

    Geez, Chuck, there was a coupla people in the stand there that were a tad overweight; you need to hit a Walmart or a Price Chopper. The ones that can walk make the display cases and walls rattle; others ride around in those goddamned golf carts. Or visit one of the chain restaurants that specialize in steaks, chops, burgers, etc. Holy shit, the buggers are humongous. And they eat whole platters of stuff; I am a good-sized guy at 6’5″ and 255 but I almost always take a doggie bag with me after meals at those joints.

  6. Raymond Thompson says:

    Any reason you use JPG rather than PNG, Ray?

    It is probably the most compatible format with all browsers, photo editing software of any kind and for people to use. That format can also be printed at any printing service. And for the kids it will also display properly on all the IPhones and other smart phones.

    When I take the images I use RAW format. After I process them I save them as JPG, generally at about 8, then lose the RAW images. These are not wedding images where absolutely the best quality is required.

    The image on the web site was saved with no compression and is about 4.5 meg in size. The PSD file is 20.5 meg, the JPG 4.7 meg and the PNG is 9.4 meg.

    I will upload the PNG file at http://www.raymondthompsonphotography.com/KellieBall.png

    I seriously doubt you will see any difference in the images.

  7. Chuck Waggoner says:

    You are right — I detect absolutely no difference at all. I figure if there is a difference to be seen, it would be apparent in the lettering on the basketballs, but after aligning them perfectly and switching back and forth, there is no difference whatever.

  8. Roy Harvey says:

    So is it just me or is it the case that female b-ball players and track-and-field girls often have spectacular legs but no racks at all?

    I think it is the way sports bras are designed, which is to keep them in place by pressing them to the body. From what I understand they are considered to be a great advance by those who need them and engage in sports.

  9. Raymond Thompson says:

    You are right — I detect absolutely no difference at all.

    For all the claims about JPG being inferior I have never really found where JPG was inferior to other formats. As long as JPG is compressed to 80 or better you are generally OK. Other formats have advantages, PSD keeps the layers, TIFF is 16 bit (vs JPG 8 bit) so you have marginally better colors, PNG is supposedly lossless but is larger, RAW has maximum detal and 12 bit color and can be easily white balanced, DNG is Adobe (may be a disadvantage).

    I used to use JPG when memory was limited in my cameras. Now with 16 gig cards I can take 400+ RAW images or about 1,200 JPG images. The advantage to RAW, and this is substantial, is that Lightroom allows me to color correct the images quite easily and (this is invaluable) adjust the exposure 1 stop either way without affecting the image quality. The dynamic range is much larger with RAW than JPG. I can go two stops but that starts degrading the image quality.

    So I use RAW to capture the initial image, white balance the image and exposure correct the image as that is the superior format for that use. After that is done I will correct issues with the image such as removing unwanted items, applying effects, etc. using a TIFF format because of the 16 bit which is a nice step up from 12 bits providing no loss in color. After all that is done I save the images as JPG. Weddings get minimal compression, others such as sport pictures get 80 (mild compression).

    For clients that want the images the JPG is fine and when I create the media I don’t have to do any conversion. JPG is all the clients receive as that is the most universal.

    There are a lot of myths about images that stem from issues years ago. These are no longer true. Some photographers still insist on using PRO labs because they think their services are better. They advocate that PRO labs will color balance and exposure correct the image. Hello!! Is that not the job of the image taker? Truth be told PRO labs use the same machines as Walgreens, SAMS or Walmart. When printing images at these places you can now request that no corrects be applied to the images. So in my opinion PRO labs offer no substantial advantage until you start getting into 20×30 and above in print sizes.

  10. Raymond Thompson says:

    I think it is the way sports bras are designed, which is to keep them in place by pressing them to the body.

    That is indeed the case. The bras are designed to dramatically restrict breast movement, same as jock straps for male testicles. You just don’t see guy’s junk all mashed up.

  11. OFD says:

    Ah, I knew this was the place to get the straight griff on young female athletes’ chests. Good on me. Thanks, mates!

    And if one did see a guy’s junk all mashed up, chances are good that said guy would be on his hands and knees on the floor bellowing in agony and spewing whatever he last ate, if not actually dying. And here’s another question: when did we all start referring to the marvelous male apparatus as “junk?”

  12. SteveF says:

    when did we all start referring to the marvelous male apparatus as “junk?”

    Despite the apparent claims of television and other popular culture, as well as white American high schoolers, not all aspects of poverty-stricken, crime-afflicted, dysfunction-ridden inner-city culture are good, with “good” meaning beneficial, uplifting, or promoting success.

  13. Miles_Teg says:

    I’d like to contribute to this discussion but since, alas, I am not an authority on women’s underwear I’ll have to pass.

  14. OFD says:

    Well then, sir, I sincerely hope you are not alternatively an authority on MEN’s underwear…not that there’s anything wrong with that….

    So I get that “good” may likely not mean what it used to mean, but how come our glorious manhood is now “junk?”

    I mean, that is like, sick, man—-oh wait, “sick” actually means “good” now, doesn’t it….

  15. Chuck Waggoner says:

    Thanks for that info, Ray. I was still suffering from the delusion that JPG was an inferior format. Dealing with video sometimes involves making a choice between PNG or JPG images. I had just assumed PNG was the better choice, but now I know.

    For all the complexities, it really is a wonder video works at all. Choices that were made in the past — like interlace scanning (tracing even lines on one pass, then odd lines next pass), chosen because of the quick fade-out rate of phosphors in the early days of television — would not even be a consideration if devising TV from scratch today. Results of just stringing together still frames in fast sequence (like filmed movies) are now perfectly acceptable.

  16. Raymond Thompson says:

    Choices that were made in the past — like interlace scanning (tracing even lines on one pass, then odd lines next pass), chosen because of the quick fade-out rate of phosphors in the early days of television — would not even be a consideration if devising TV from scratch today.

    The addition of the chroma signal to get color, vertical blanking intervals with repeated spikes to sync it all up, horizontal retrace that in old TV’s was used to generate the high voltage, odd/even frames. It is amazing that it worked in an analog world with remarkable results. Now I have no idea what is involved in the digital signal of today.

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