Category Archives: Science

Iranian Homebrew Fission- Fait Accompli? Rev 1.1

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Iranian progress towards nuclear fuel processing seems to have everyone twittered. Recently on NPR a guest raised the question as to whether or not Iran has enough reactor capacity to consume the potential output of their nascent uranium enrichment program.  Good question.

The refinement of fissile materials offers hazards that are poorly understood outside the actinide community.  One of them is the “criticality” hazard.  In the US nuclear program, there have been a few criticality events leading to heavy radiation dosages and even death in a few cases, i.e., Louis Slotin.  Slotin’s case is unusual in that he was manipulating a subcritical bomb assembly rather than a uranium solution. A recent example is the criticality event at Tokai-mura.  According to the literature, numerous elements (in addition to beryllium) absorb alpha’s and then emit neutrons.

One wonders if the Iranians have the infrastructure to safely perform this activity.  A nuclear state needs a health physics community, sensitive and accurate radiation detection systems, and the ability to handle hazardous radioactive materials that are chemical hazards as well. Then there is the matter of what to do with high level rad waste.  The US is still struggling with its rad waste inventory generations after the Manhattan project began.  Who knows, maybe NIMBY isn’t an issue in modern Persia.

Nuclear weapons seem so secular for hyperorthodox nations. But these things do capture the fancy of many people- even followers of the worlds major Iron Age religions. Among scientists, the explosive runaway potential was considered not long after it was discovered that nuclear fission released two neutrons per fission.  The human brain seems constructed to find extrema.

I wonder how the Iranians will validate their weapon’s design? I assume their program is not an ab initio project.  No doubt they have culled design information from somewhere (Pakistan?).  Eventually they have to assemble their weapon and tighten the wingnuts on the casing.  But how will they know if it has enough thump?  Will they be able to resist performing a test shot?  Israel, to its credit, has not performed a test of theirs, though I have no doubt that considerable super computer time has been dedicated to validating their design.

How will these sons of Xerxes construct the chain of command for the release of nuclear weapons?  What kind of fail-safe mechanisms will they put into place to safeguard against inadvertant or unauthorized arming and detonation? Even martyrs have to be careful.

Nuclear weapons have their military uses, but they are primarily a political amplifier used by states to project their voice on the world stage.  But what happens when a religion gets hold of nuclear weapons?  Clearly, the Islamic Republic of Iran is interested in more than mere self defense.  They seem compelled to promulgate standards and doctrines given to them in the form of revealed truth.  A nuclear weapon is as much about prestige and credibility as firepower. 

The Iranians are very pragmatic people.  They know that the US can easily rain nuclear destruction on them and then bounce the rubble a few times for good measure.  They’ll use the bulk of the uranium for electrical power generation.  But they’ll be sure to use a part of it for politcal power generation.

Purchasing Chemicals from China

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I’m having to search far-off China for raw materials much more frequently these days. The availability of many US manufactured chemicals is slowly falling off.  Especially for really basic materials.  I’m not referring to those mundane elements like iron or soda ash or copper. No no. materials from the folds and deep recesses of the periodic table. Elements with relativistic electrons.  There are short term economic pluses and minuses to this migration of manufacturing.

On the plus side, Chinese prices are often, well,  quite low. Even with multimodal freight charges from across the Pacific. When you pay peasants fresh off the farm $40/month (or whatever insane wage it is), you can undercut nearly everyone in pricing. 

But there is a down side to spot buying from China.  This is to be distinguished from contract purchasing.  In contract purchasing, you work out an agreement with a manufacturer and you lock in quality, price, and delivery in exchange for long term business.  Spot buying, however, is much more risky. What do I mean by that?

Spot buying is where you find a merchant supplier who can furnish material without the fuss and obligations of a contract.  Either they have it in inventory, they can source it quickly, or they themselves will make it pronto.  A supply contract has to be managed or enforced.  For raw materials that are less than critical, finding a spot supplier makes sense. 

Locating a spot supplier in China that you can trust is problematic. I’m not suggesting that Chinese suppliers are dishonest.  I am saying, however, that culling out a supplier from a list of unfamiliar names from the other side of the world without the benefit of a site visit or a Dunn and Bradstreet report can be risky. Spot buying anywhere is risky, but when it is complicated by international transactions, the risk multiplies a bit.

It is relatively easy to find contacts on the web that will reply to an RFQ (request for quotation) by email (often “hotmail” accounts) and make an offer.  But what you find is that you may be in contact with an agent of some description in an office suite in Shanghai, far from the factory.  Indeed, it is hard to tell just what the relationship is between the factory and your contact.  To salve over some of the uncertainty westerners may have, it is common now for these web contacts take on western names. 

Brokering goods is common in some parts of the world and scarce in others.  In the USA, brokering chemicals is fairly uncommon.  Most US companies prefer to do bulk business with the manufacturer or a catalog house.   Sigma Aldrich, for instance, is both a catalog company and a manfacturer of bulk and semi-bulk materials.  Purchasing from a broker (as opposed to a distributor) rather than the manufacturer will add costs to the transaction.  A broker is someone who connects the purchaser with the supplier.  Usually they perform drop shipments to the purchaser directly from the manufacturer.  A broker is a sort of “free agent” sales group.

I have found that there is a greater reliance on brokering in Asia and to a lesser extent, the EU.  The internet has made life a bit trickier for brokers in that a search for manufacturers is a lot less painful than it used to be.

A company will work through a broker for several reasons. Brokers are usually specialists, so a company can tap into considerable expertise in supply chain management.  And, the broker only gets paid if they find a qualifying supplier, so a manufacturer could conceivably keep the head count down. Brokers might be better at the intricacies of negotiation as well.  There are a lot of tough guys running companies out there who are actually poor negotiators.

These agents seem to work in organizations that carry on the sales and marketing activity for a factory or a series of factories.  In addition to unfamiliar business practices, there is the matter of payment.  Many Chinese companies want prepayment- they do not automatically offer 30 days net.  This makes company controllers and project managers nervous.  Since this is an international transaction, customary business laws covering remedies are not applicable. In other words, you can get royally screwed. But from their perspective, it is the same issue.  So settling into a supply relationship can take time.

Ullage Motors

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If the reader is interested in the history of aerospace or rocketry, I’d like to recommend the book Saturn, by Alan Lawrie and Robert Godwin, Apogee Books, 2005 (ISBN 1-894959-19-4).  Lawrie is the author and Godwin produced the DVD that is included. The book is a comprehensive history of the Saturn V launch vehicle. 

Flipping through the book I happened to land on page 59 and a section on Ullage Motors.  If you have ever handled bulk liquids in drums or tankers, you know that there must be a certain fraction of the tank capacity left unfilled with liquid.  This gas space, or ullage, prevents rupture of the vessel by expansion of the liquid contents.

Ullage motors were used to get around certain problems associated with using liquid phase propellants in weightless conditions. The contents of a liquid propellant tank always include a volume of ullage.  In free fall it is possible for void spaces to form near the propellant transfer lines. 

Saturn V ullage motors were ammonium perchlorate solid rocket motors externally mounted on the lower part of the second stage.  Immediately after first stage engine cutoff, the first stage would separate and for a short time the upper stages would be in free fall.  To prevent transient fuel starvation problems during engine start it was desirable to force propellant to the bottom of the fuel tank prior to the engine start.  To accomplish this, a group of small solid rockets were fired to provide a bit of acceleration to force the liquid propellant to the bottom part of the tank. The eight ullage motors burned for 4 seconds and each generated a reported 22,500 lbs of thrust. 

Curiously enough, there are a reported 46 intact ullage motors in earth orbit.  The authors conclude that these remnants of the Proton 4 rocket represent explosion hazards. 

To the Moon!

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It is hard for most of us to tell but the US is in the early phases of a moon project.  It has adopted the same configuration of command module and lander as the Apollo program.  NASA intends to make a few exploratory missions lasting a week or so and then develop the capability for 180 day missions to the moon. This lunar “base” project is really a local rehearsal for a more ambitious manned Mars landing.  It is called the Constellation Mission. 

NASA has announced the development of two rockets for this mission- the Ares I and the Ares V.  The Ares I uses an in-line single solid rocket booster (SRB) for the first stage and a liquid propellant second stage to boost a 55,000 pound payload into low earth orbit.  Ares I is equipped with a emergency escape rocket in a tractor configuration analogous to Apollo.  As stated in the website, Ares I will be used to put the crew module in orbit for rendezvous with the ISS or cargo modules. 

The Ares V uses two SRB motors strapped to a liquid first stage engine in a fashion similar to the space shuttle. But the crew module will not be on this system.  Ares V is a cargo lifter and will carry 286,000 lbs of mass into low earth orbit.

NASA will be retiring the space shuttle system in a few years. The next man-lifter will be Ares I.  Evidently their faith in the SRB system is high.

That sucking sound heard around NASA these days is the sound of money being pulled from all over the agency and being dumped into this program. We’re going back to the moon, but with no real increase in funding.  Program managers are nervous. 

Wherein Gaussling Laments the Demise of Chemical Photography

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A sad day it will be when the last image is captured on a photographic emulsion. The transition from chemical photography to digital photography is well underway.  Indeed, it is clear by a simple visit to a big box store that the amount of shelf space given to film cassettes vs digital cameras & accessories is rapidly tipping in favor of the digital.  Consumer demand is well past the cautious early-adopter stage in its evolution.  Many people are several generations into digital photographic equipment. 

I own a low end Hewlett Packard Model P.O.S.  digital camera with a 4.1 megapixel chip.  I suppose I’d be happier with it if it still worked.  Even when it did work, it was a P.O.S.  As long as nothing moved, the image was sharp and the colors were true.  But given the slow shutter response, the slow shutter speed, and the heavy power demand on the battery, using it was a maddening experience. Evidently a capacitor has failed because the flash fails to fully charge. 

Printing is still a chemical process, one way or other.  Printing consumables like paper and inks/dyes are a major cash cow for all of the manufacturers of printers. 

I do not consider photocopier xerography to be strictly digital imaging.  I consider it to be a form of chemical photography because, despite the use of computer driven laser arrays and electrostatics in image formation, there remains a deep and intricate art in the chemistry of the toner composition.  I have actually done some color toner R&D and can attest to the high art required in that field.

Th’ Gaussling laments the demise of chemical photography, at least on the camera side, because of the highly advanced color chemistry knowledge that will inevitably be lost. Lost because skilled practitioners in the manufacture of color films will retire, labs and plants will be shuttered, and the use of color films will dwindle to low volume.  Soon, say 20 years from now, only eccentric purists and “hobbyists” will capture images on emulsions.  Drug stores will sell off their developing equipment to people who drive VW Beetles in Guatemala and fill the space with racks of diabetic candy, NASA diapers, and $4.99 DVDs. 

Soon, the experience of dodging a poorly exposed image under the projector, swishing print paper in developing solution under red light, and experiencing the magic of seeing an image appear will be lost to future generations.  The smell of acetic acid and the darkroom clutter of wet film hanging from string will be but a distant memory of the “old ones”. 

When I get to the nursing home I’ll regale my fellow geezers and codgers with harrowing tales of nights spent outside at the telescope shooting time exposures with hypersensitized Tri-X.  They’ll nod off in boredom and I’ll switch on a Star Trek rerun and fall into a deep slumber while Kirk and Spock contend with the Tholian Web.  ZZzzzzz.

Infotainment, Chemistry, and Apostasy

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In the normal course of things Th’ Gaussling gives school chemistry talks or demonstrations a couple of times per year and until recently, I had been giving star talks at a local observatory more frequently.  The demographic is typically K-12, with most of the audience being grades 3-8.  From my grad student days through my time in the saddle as a prof, I was deeply committed to spreading the gospel of orbitals, electronegativity, and the periodic table. I was convinced that it was important for everyone to have an appreciation of the chemical sciences.  I was a purist who knew in his bones that if only more people were “scientific”, if greater numbers of citizens had a more mechanistic understanding of the great intermeshing world systems, the world would somehow be a better place. 

In regard to this ideology that everyone should know something about chemistry, I now fear that I am apostate.  I’m a former believer.  What has changed is a newer viewpoint based on some observations.  

Chemical knowledge is highly “vertical” in its structure.  Students take foundation coursework as a prerequisite for higher level classes.  Many of the deeper insights require a good bit of background, so we start at the conceptual trailhead and work our way up. But in our effort to reach out to the public, or in our effort to protect self esteem, we compress the vertical structure into a kind of conceptual pancake.  True learning, the kind that changes your approach to life, requires Struggle.

What I find in my public outreach talks on science- chemistry or astronomy- is the  expectation of entertainment. Some call it “Infotainment”.  I am all in favor of presentations that are compelling, entertaining, and informative.  But in our haste to avoid boredom, we may oversimplify or skip fascinating phenomena altogether. After all, we want people to walk out the door afterwards with the answers. We want Science to be accessable to everyone, but without all the study.

But I would argue that this is the wrong approach to science.  Yes, we want to answer questions.  But the trick is to pose good questions.  The best questions lead to the best answers.   People (or students) should walk out the door afterwards scratching their heads with more questions.  Science, properly introduced, should cause people to start their own journey of discovery. Ideally, we want to jump-start students to follow their curiosity and integrate concepts into their thinking, not just compile a larger collection of fun facts. 

But here is the rub. A lot of folks just aren’t very curious.  As they sit there in the audience, the presentation washes over them like some episode of Seinfeld.  I suspect that a lack of interest in science is often just part of a larger lack of interest in novelty.  It is the lack of willingness to struggle with difficult concepts.  But that is OK.  Not everyone has to be interested in science.

Am I against public outreach efforts in science?  Absolutely not.  But the expectation that everyone will respond positively to the wonders of science is faulty.  It is an unrealistic expectation on the 80 % [a guess] of other students who have no interest in it.   I’m anxious to help those who are interested.  It’s critical for students interested in science to find a mentor or access to opportunity.  But, please God, spare me from that bus load of 7th graders on a field trip. 

What we need more than flashier PowerPoint presentations or a more compelling software experience is lab experience.  Students need the opportunity to use their hands beyond mere tapping on keyboards- they need to fabricate or synthesize. You know, build stuff. 

It is getting more difficult for kids to go into the garage and build things or tear things apart.  Electronic devices across the board are increasingly artifacts of microelectronics.  It is ever harder to tear apart some kind of widget and figure out how it works.  When you manage to crack open the case what you find is some kind of circuit board festooned with cryptic resin-encased devices. 

The emphasis on information technology bypasses the fact that we still need to build things.  Kids need to develop their mechanical skills. And they do that by building things. 

Friday Link-o-Rama

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The Russian cruise missile submarine Kursk went down in the Barents Sea, killing all aboard.  The first link has interesting pictures of the remains of the sub after it had been recovered. The second has interesting background information.

Need a spectrograph for your backyard telescope?  Check out this cool instrument from SBIG.  The good folks at Brookhaven have a table of nuclides online as well as a “Nuclear Wallet Card“. Golly, maybe one day we’ll have electricity too cheap to meter…

Check out the Deep Space Exploration Society- DSES.  They have resurrected a pair of dishes for the purpose of amateur radio astronomy.  They have been doing a sky survey at 1420 MHz.

Looking for something more refractory than the head of Karl Rove?  Check out FiberFrax.

Boron Cosmochemistry

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Next time you wash your laundry with borax, pause for a moment and consider the path those boron atoms took to get to your dirty shirts.  The Big Bang started the universe with H, He, and maybe a bit of Li.  The rest of the periodic table had to be produced by nuclear reactions within the core of a star or during the explosion of a star.  This occurs through either the fusion of charged nuclear particles (nuclei included) or absorbed neutrons to nuclei, perhaps followed by a decay cascade.  Note to reader: astronomers are in the habit of referring to elements heavier than helium as a “metal”. 

In the core of a star there exists a complex kinetic circus of multiple simultaneus synthetic channels involving both atomic weight buildup and disintegration.  Nuclei less sensitive to the reaction conditions may accumulate and delicate nuclei like boron have but a fleeting existance and are consumed.  In addition to stability to the reaction conditions, particular combinations of protons and neutrons tend to be more stable and accumulate if only by the lack of propensity to decay. 

While the elements C, N, and O are cosmically quite abundant, at least in comparison to the rest of the elements (3 to 92), the elements Li, Be, and B (LiBeB) are relatively scarce. 

Because boron was too heavy for Big Bang nucleosynthesis and too reactive to accumulate in a stellar core, it’s cosmic abundance is low.  What little that is found did not arise as simple boron ejecta mechanically boosted into the interstellar medium by an explosion or as entrained mass from stellar wind.  It was formed from more abundant elements like CNO that had already been ejected- elements that would be subjected to a barrage of highly energetic particles.

LiBeB are thought to be “spallation” products from interstellar CNO collisions with cosmic rays.  From the linked chart, we can see that C, N, and O are relatively abundant.  So over a multibillion year timeframe of stellar evolution, early massive stars can live and die, dispersing metals into nearby space.  Accumulated heavy elements can then be exposed to cosmic ray fragmentation.  The source of the cosmic ray particles in these collisions is somewhat up in the air.  Some of the latest thinking suggests that these energetic cosmic rays yielding spallation products are from especially energetic sources like Wolf-Rayet stars or type II supernova events.  There is an indication that boron can come from two spallation channels- cosmic ray and neutrino-induced spallation of carbon. 

So, the picture thus far- boron arises from the energetic collision of particles outside of a star.  Heavier nuclei will fragment under cosmic ray bombardment and some combination of B-11 and B-10 are formed.  What is interesting is that this is a dispersive phenomenon.  By contrast, on earth, boron is found in deposits as the hydrate of the alkali metal salt of the oxide- Borax.  There are a variety of distinct mineral compositions that contain boron.  On earth, a bit of the dispersed boron was somehow concentrated into ore bodies.  This is where geology kicks in.

Hydrothermal action near subduction zones can dissolve borates in hot, pressurized water and deposit them at the surface where the solid borates come out of solution on cooling.  This process evidently partitions the isotopes of Boron slightly.  Over time the process continues until geological events interrupt the deposition process.  If the solubility of the borates is relatively low at surface temperatures and pressures, then weathering will not further disperse them into the hydrological cycle.  Thus they form a deposit.  Layers of sediment accumulate over the borax deposit and eventually geological processes move the layer underground. Eventually, uplifting, weathering, and mining makes the deposit accessible.  Through the miracle of marketing, distribution, and 18-wheeler trucks, this spallation product can be used to clean that unsightly mustard stain from your shirt.

News Flash! Most energetic supernova ever observed was detected in the galaxy NGC-1260 by Chandra.

A beautiful day in the neighborhood

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This early May morning was crisp and sunny in our small neighborhood wetland park. Looking west through polarized lenses, the scattered cumulus clouds stood out against an azure blue sky and above fresh snow in the high country. The drone of a Cessna overhead lowered in pitch as the pilot throttled back to decend a bit.  Gonna buzz somebody’s farm from the sound of it.  The fresh layer of snow covers the front and back ranges of the Rockies down to what I’d estimate as the 6000 ft level just a few miles west.  Missed snow by a thousand feet of elevation yesterday.

In the marsh, last seasons cattail stems bounce enthusiastically as red-winged blackbirds jump from stem to stem, pausing for a moment to make their call.  As they sing the long black triangle of their beaks bisect open and a shrill call issues.  As they call their splayed tails drop in unison with the sound, causing the cattail to nod in time with their song. 

These birds are scrappy buggers.  Frequently they join in squabbling groups while in flight to settle some kind of dispute known only to them.  As quickly as it started it is finished and the individuals disperse.