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04/10/2003
Solder, Diamonds and Fire
On Monday, a fellow morning walker at our local mall remarked,
“It’s a topsy-turvy world.” He was referring primarily to the
imminent April snowstorm, which arrived, as predicted, a few
hours later when I started this column. It was a winter
wonderland outside, but who needed it. It was a rough winter
and, inside, I had just watched the Today Show’s tribute to their
fallen colleague, David Bloom. While Bloom lacked the
resonant voice of a Tom Brokaw or the avuncular authority of a
Walter Cronkite, he came across to me as a truly nice guy who
would have made a great friend or neighbor. It’s a shame that
Bloom did not live to see what I’m witnessing as I write today,
Wednesday, April 09, 2003 – the Iraqis themselves are trying to
topple a statue of Saddam Hussein in Baghdad. It is indeed a
topsy-turvy world.
In keeping with this week’s theme, this will be a topsy-turvy
column. At first, I thought an update on the current status of the
work of diamonds or diamond-like materials in electronics might
be appropriate. However, an item in the March 31 issue of
Chemical and Engineering News turned me off that subject. The
item cited a report in the Syracuse, N.Y., Post Standard about the
most unusual disposition of the remains of a young woman who
died last September of Hodgkin’s disease. As I’ve mentioned in
earlier columns, one way to make diamonds is to subject carbon
to high pressures and temperatures. After cremation, this young
woman’s remains were sent to a Chicago company by the name
of LifeGem. LifeGem reportedly extracted the carbon from the
remains and shipped it to Germany. There, the carbon was
heated and pressed for eight weeks. The resulting six half-carat
diamonds were presented to her family. I’m trying to sort out my
feelings about this marriage of technology and remembrance. It
gives new meaning to the slogan “A diamond is forever.”
These past three weeks, David Bloom and his journalistic
compatriots gave us many scenes of explosions and fires. From
the environmental standpoint, we are fortunate that the number
of oil fields set afire have been few compared to the number of
such fires in Kuwait during the Gulf War. The environmental
consequences of manmade fires and of Nature’s own fiery
machinations are topics that will reclaim our attention when the
Iraq war is over. The controversies will resume concerning the
proper management of our forests to prevent and/or control the
wildfires that garnered so many headlines last year.
In an article titled “Forgotten Fury” by John Steele Gordon in the
April/May 2003 issue of American Heritage, I found that
concern over forest fires is nothing new. You might recall one of
the most horrendous natural disasters in U.S. history, the fire of
1871 in the area of the town of Peshtigo, Wisconsin. Never
heard of Peshtigo? Neither had I until I read the article. Therein
lies a tale.
In the 1800s, the demand for timber for our expanding young
country was prodigious. For example, by 1896 Michigan had
shipped 160 billion board feet of white pine. This left only 6
billion remaining. Wisconsin also had plenty of virgin forests,
some of which bordered the little town of Peshtigo, through
which flowed the Peshtigo River that emptied into Green Bay a
few miles away. Millions of board feet of timber had been
sawed in 1871. Logs were piled up in the forests and mounds of
sawdust and other debris abounded. It was anticipated that the
logs would be carried down river to the mills with the following
year’s spring runoff. However, a severe drought, with no
significant rain since early July that year, brought the area to
tinderbox conditions and by early October there were many fires
smoldering in the ground cover of the forests.
On October 8, a wall of fire descended upon the town and the
lone fire engine proved useless. Everyone ran for their lives,
their only hope being the river, which became filled with people
and animals. Within less than 2 hours, the town was gone. The
surrounding area was hit by not only that fire but also by another
fire on the other side of Green Bay. Nobody knows the exact
toll, but it is estimated that 1,125 people lost their lives. In one
small area, 267 bodies were found. Over a million acres, nearly
2000 square miles, had burned.
Why don’t we remember Peshtigo? It’s the power of the media
and of city folk. On the same day, October 8, 1871, Mrs.
O’Leary’s cow did its thing (possibly?) and a third of Chicago
burned to the ground. However, with 250 killed in the fire, it
was 4 to 5 times less costly in human life than the Peshtigo fire.
Environmentally, I’m sure the Chicago fire did much to
encourage the widespread introduction of more fire resistant
structures as well as more effective firefighting procedures in
cities. With regard to more rural wooded areas, Peshtigo’s
experience seems not to have provided definitive answers on
proper forest management. The scientific/political controversy is
still raging concerning selective cutting of timber as the way to
go to prevent catastrophic forest fires.
Now let’s turn to the topic of solder and soldering. You perhaps
wonder how solder fits in here? I told you it would be a topsy-
turvy column; however, there is an environmental aspect. If you
haven’t personally soldered anything, you must have watched an
electrician or plumber at work with a torch or soldering iron. The
problem with solder, at least with the most common types of
solder, is that solder typically contains lead. Environmentally,
lead is a no-no. We’ve all seen reports of children suffering from
the ingestion of lead, typically from lead-based paint. In the past
few decades, we’ve seen the demise of lead additives in gasoline
and the introduction of lead-free paints. Now the hunt is on for
solders that don’t contain lead but perform as well as lead-based
solders.
This search is also proceeding in the world of microelectronics.
Perhaps you have seen or personally examined a printed circuit
board in a phone or taken from a computer. If you turn the board
over and look at the back you’ll see a large number of soldered
connections. With the huge numbers of electronic devices in our
society these days, there are increasing numbers of printed circuit
boards being thrown out and ending up in landfills. Leaching of
the lead from the solder connections has become a significant
environmental concern.
However, the search for lead-free solders in the electronics
industry is not just an environmental concern, as I learned from
an article in the January 2003 MRS (Materials Research Society)
Bulletin by Darrel Frear and Simon Thomas. As the devices on
your silicon chips have gotten smaller and smaller, they become
more fragile with respect to stray charges, possibly from static
electricity, and to stray particles, cosmic rays for example. These
stray charges or particles may either kill a memory device or,
alternatively, may change the state of the device. If the device is
storing a 1, it may be hit and changed to a 0. This “soft” error
may not sound like much but if it shuts down your computer, it
won’t feel soft to you!
What intrigued me was a statement in the MRS Bulletin article
that all mined lead contains a bit of an isotope of lead, Pb210.
This lead isotope is radioactive and emits alpha particles, which
are essentially just helium atoms stripped of their electrons.
These alpha particles aren’t very energetic so I don’t think we
have to worry that we are being bombarded by them when using
our cell phones or computers. However, in a soldered
connection they are quite close to our memory chips on the
printed circuit boards. If an alpha particle strikes a memory cell
it can flip the cell from a 1 to a 0 or vice versa and your soft error
results.
So, how do you avoid this problem? One way is to go out and
find a sunken ship, an ancient sunken ship! The lead in that ship
was mined so long ago that the troublesome lead isotope has
decayed away. The lead is no longer giving off those alpha
particles. As you might imagine, finding and reclaiming lead
from ancient sunken vessels can be expensive! Better to find a
solder that only contains elements like silver, tin, bismuth or
other metals that do not have radioactive isotopes to blast our
memory cells. The search is on.
So much for this potpourri of environmental and other issues.
The environment outside my window has improved – the four
inches of snow is now just slush. The statue of Saddam is
down. And, welcome back LAMB!
Allen F. Bortrum
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