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Week of 3 March 2008

Latest Update: Saturday, 8 March 2008 08:59 -0500

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Monday, 3 March 2008
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07:59 - Dinner last night with Paul and Mary.

I made a small bet with Barbara. I told her that when the food arrived, I was going to announce, "Do you mind if I say grace?" Barbara bet I'd get dumbfounded looks. I bet that one or the other, probably Mary, would reply, "Only if you say it out loud." This is, after all, the woman who used the quote "We've done the impossible, and that makes us mighty" as the headline for her final BluePlanetRun.org blog entry.

Alas, Barbara won. When I asked Mary if she minded if I said grace, she replied, "Do you want to?" What was she thinking?

I'm getting into the home forensics lab book. One of the fun things about writing a book like this is figuring out how to make the procedures and technologies accessible and affordable for home scientists.

For example, right now I'm stubbing out a lab session on using chromatography to analyze drugs. Professional forensics labs indeed use chromatography for this purpose, but ordinarily they use TLC (thin-layer chromatography), GC (gas chromatography), and HPLC (high performance/pressure liquid chromatography). GC requires expensive equipment. LC (if not HPLC) can be done in a home lab using a burette for the column, but requires substrates that are relatively expensive and difficult to come by. Even TLC requires TLC plates, which are available as far as I've been able to determine only in bulk quantities much larger (and more expensive) than are suitable for home labs.

My first thought was to make TLC plates from microscope slides, using albumen (egg white) or Elmer's Glue as the binder and cornstarch, talcum powder, or crushed silica gel from drying packets as the stationary phase. And that actually works pretty well. The problem is that it's time-consuming and picky work, and I don't think the result is worth the time required. So I decided to use simple paper chromatography, which also works pretty well and is as useful to illustrate the principles as the less accessible chromatography methods.

The remaining problem is processing the chromatograms. Most home science chromatography experiments use brightly-colored samples, such as food coloring or inks, so no further processing is required once the chromatograms are developed. For drugs, it's a bit more involved. For example, I plan to separate aspirin, acetaminophen, ibuprofen, naproxen, and caffeine, all of which are common components of OTC painkillers (at least in the US; naproxen is still a prescription drug in most of the world.)

All of those are colorless compounds, at least in the concentrations present on a developed chromatogram. So I need some means to process the developed chromatogram to make the samples visible. I'll probably use UVA (a "black light" BWB tube) and iodine fuming, but I need to do some experiments to verify that those two methods will in fact reveal the samples.

Another lab session from the same chapter is about identifying specific drugs by examining their microcrystalline structure under the microscope. Although white light is somewhat useful for this purpose, what's really needed is polarized light. But if you check out the prices of polarizing microscopes, you'll find they're out of reach for most home scientists.

So, I searched Google for "polarizing film" and found that Edmund Scientific sells 2" (5 cm) squares of polarizing film, two for $7.50. I'll put one of those under the stage somewhere, probably on top of the illuminator or under the condensor. That will be the fixed filter. I'll mount the other piece of film in cardboard and hold it between my eye and the ocular, rotating it as necessary.

Cool. I just came across a page that describes what looks very much like the high-speed camera we used the summer before I left for college to measure how fast I served a tennis ball. I was thinking the name of the camera was something like Hulcher, but this Wollensack Fastax model looks a lot like the camera we used, as best I can remember after nearly 40 years. The text says this camera operated on AC, but I remember that the one we used had a large, heavy battery pack. It also mentions a fixed frame rate of 5,600 frames/second, while I seem to recall that the one we used had variable speeds up through something like 5,000 or 10,000 frames/second. I do remember the screeching noise, though.


Tuesday, 4 March 2008
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08:07 - Here's a disturbing article from Ed Foster's Gripelog. Apparently, most or all current televisions are built with replaceable modules. The problem is, manufacturers produce a very limited number of replacement modules during the production run of the specific model and then stop producing the modules. If your set fails out of warranty, chances are it's not repairable. And it's very likely to fail early because nowadays, thanks to EU regulators, essentially all consumer electronics are built using lead-free solder, which fails early and often catastrophically due to the growth of tin whiskers.

Not that long ago, a television was likely to give good service for a decade or more. Some units failed earlier than that, of course, but they could be repaired. Nowadays, because new modules are no longer available and old modules cannot be repaired, the expected lifespan of a new television set is, what, maybe four or five years? And when it fails your only option is to scrap it and buy a new one, which will be no better than the one you're replacing. Talk about a scam.

This is just one more reason to avoid HDTV. We'll hang on to our 27" analog Panasonic until it gives up the ghost. And we have a 25" unit down in the guest suite, along with a 20" unit (with our only remaining VCR built-in). We could continue watching TV and DVDs on them until they die. At that point, I don't know what we'll do. It may be we'll just decide to stop watching TV entirely.


Wednesday, 5 March 2008
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08:25 - More on TVs dying young.

From: Christensen, Chris (Aspen Research)
  To: Robert Bruce Thompson
Date: Tue Mar  4 11:56:45 2008
  Re: Rohs whining

Robert: From the Ed Foster article, excessive whining. First, the fluid in electrolytic capacitors is not corrosive. It might be poisonous, or a deadly carcinogen, but it has to be a material with a high and stable dielectric constant, i.e., no charge carrying ion species, which eliminates acids and caustics. It's in an aluminum can for pities sake. The electrolytic caps I've failure analyzed used ethylene glycol for a dielectric fluid. Big ones may have used polychlorinated biphenols (in the past).

As far as ROHS compliant (lead free, among other elements/compounds) devices, there are issues, but I know that the disk drive manufacturers (one to my personnel knowledge) have worked very hard on reliability of lead free solder joints. I assume other computer part manufacturers are working diligently to produce reliable devices. There's enormous amounts of literature on succesful implementation of lead free solders. As far as tin whisker formation, that was understood and solved by AMP (tin plated terminals, static switches, etc..) more than 40 years ago. I had the pleasure of being able to consult James Whitley (from AMP, since deceased) back in the 80's about a tin contact problem.

My opinion is that whining about ROHS and lead free solders is a way to distract the end user from the fact that the devices in question are outsourced to countries that don't bother to obtain reliable starting materials (solders, fluxes, etc..), won't read the literature and follow well established procedures to make reliable devices, and won't accept responsibility for their own work. It doesn't matter whose name is on the device if the work is outsourced to the lowest cost gypsy producers that can be found.

Here's nine-inch nails in the coffin of the music labels. Trent Reznor, the front-man for Nine Inch Nails, decided to bypass the music labels entirely for their latest album. Reznor "gets" the Internet, and in fact has admitted to using P2P services to download music himself. The new album is available only directly from the band, and they're offering several options, from a free download to a $300 limited-edition deluxe set. That $300 deluxe set is limited to 2,500 copies, and they sold out within a day of the announcement.

I confess that I know nothing about Nine Inch Nails. As far as I know, I've never heard one of their tracks. But I just finished downloading the nine free tracks, and when I have a moment I'll give them a listen if only to support a band that really gets the Internet. If I like it well enough to pay for it, I'll send them the $5 to get the remaining 27 tracks. Which is the whole idea.

While I was munching around yesterday, I came across the Digital Entertainment Survey 2008 (PDF). It's pretty comprehensive. Although it's based on survey data from the UK, I suspect much of what it concludes is also pertinent for the US. I found this chart fascinating. Notice what's at the upper right of the chart. Reading books is, except for listening to the radio, the most popular activity, and the one that people are most attached to. There may be hope yet.


Thursday, 6 March 2008
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08:45 - Here's some good news: FCC Okays Nudity On TV If It's Alyson Hannigan. Thanks to Brian Bilbrey for the link.

Right now, I'm in research mode for the home forensics lab book, and I'm learning a bunch of new stuff every day. A lot of the books I've bought are old--anything from 1950 back to about 1890--because I need to find out how things were done with wet chemistry back before instrumental analysis methods were available. But I also have quite a few current books, which I'm reading to get up-to-date with current practices.

I was reading one of those yesterday to learn about current state-of-the-art in forensic geology. I was surprised to learn that density-gradient columns, although still in wide use for soil analysis, are no longer considered a definitive forensic test.

Density-gradient columns are simple conceptually. You start with two tall glass cylinders and two liquids of different densities, most commonly bromoform (density 2.89) and bromobenzene (density 1.499). You prepare the two cylinders identically. For example, you might start by pouring 50 mL of bromoform into each cylinder. You then make up a solution of 45 mL of bromoform and 5 mL of bromobenzene, which has a density slightly lower than pure bromoform. You carefully pour 50 mL of this solution into each cylinder, being careful not to mix the second solution with the first. The goal is to end up with two layers in each cylinder. Then you make up a solution of 40 mL of bromoform with 10 mL of bromobenzene, and add it as a third layer to each cylinder. You repeat that process with 50 mL each of bromoform/bromobenzene solutions mixed 35/15, 30/20, 25/25, 20/30, 15/35, 10/40, 5/45, and finally pure bromobenzene.

You then allow the two cylinders to sit undisturbed overnight, or sometimes for 24 to 48 hours. During that time, the solutions blend and you end up with cylinders full of liquid whose density varies smoothly from 1.499 at the top to 2.89 at the bottom. You then prepare the unknown sample and a known sample for comparison by drying them and sifting them to obtain subsamples with similar particle sizes. You add equal masses of the unknown to one cylinder and the comparison known to the other cylinder and allow the samples to settle.

Once the samples finish settling, you end up with two cylinders full of fluid with horizontal striations where the different components of each sample have achieved density equilibrium, essentially providing a "fingerprint" of each sample.

This all sounds very scientific, and frankly I don't see anything at all wrong with it conceptually. People have been convicted of major crimes based solely on density-gradient column evidence, and even now some forensic scientists testify to such evidence in court. The problem is, the density-gradient column method is not definitive but at most suggestive. No less an authority than the world-renowned forensic geologist Raymond C. Murray has stated, "But some professionals still emphasize the advantages of the density-gradient column method: you can train any idiot to do it, it produces pretty pictures for a jury, and nobody has to think."


Friday, 7 March 2008
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07:59 - I ordered a microscope from Home Science Tools yesterday. The model I decided on is the National Optical 161, which is a dual-head microscope. I need the second head for shooting images. I already have a microscope adapter for our Pentax DSLRs, so it looks like I'll be learning something about photomicroscopy.

After talking it over with Mike, my contact at National Optical, I ordered the 161-ASC model, which has upgraded objectives. I also ordered the 965-160 eyepiece reticle.

Why National Optical? Obviously, if my budget was unlimited, I'd have bought a German or Japanese scope from Leitz, Zeiss, Nikon, Olympus, or one of the other top brand-name manufacturers. Unfortunately, prices for those scopes start in the low- to mid-four figures and rapidly head up into five figures. That not's practical for me. Even more important, it's not practical for my readers.

I needed a microscope that offered good optical and mechanical quality at a reasonable price, and nowadays that means buying a Chinese scope. As is generally true of Chinese products, Chinese microscopes range in quality from quite good to incredibly poor. I did some checking around and found that National Optical has a reputation for offering the best Chinese microscopes available, and at reasonable prices. The model I ordered, for example, retails for about $725 and has a street price about $100 lower. That's not inexpensive by most people's reckoning, but it sure beats the $2,000 or more that a similar German or Japanese model would cost.

And this is actually more microscope than my readers will need. When I told Mike that the market for the book was middle- and high-school students and home science enthusiasts, he pointed out that the Model 161 is a university-level scope, and more than my readers would really need, even without the upgraded objectives. It was when I pointed out that I needed to shoot images good enough to be published in a book that Mike suggested going with the upgraded objectives, because photography is much less forgiving than visual work.


Saturday, 8 March 2008
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08:59 - I got the first of the QC2 galley proof PDFs yesterday. I've posted the Preface and chapters 1 through 3 on the subscribers' page. Others will follow as I receive them. There are some minor changes to be made, but these are pretty much what the printed book will look like. If you take a look at them, please let me know if you see any problems. (I've already told me editors about the hanging paragraph problem in the volumetric glassware section in chapter 3, so you needn't point that one out.)

We're getting very close now. There'll be only minor corrections to the galley proofs, after which the book will go to the printers. As far as I know, the projected date for availability is still 1 April, although that's really pushing it, particularly for a 4-color book. My guess is that it'll be more like 1 May, but we'll know soon enough.


Sunday, 9 March 2008
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Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Robert Bruce Thompson. All Rights Reserved.