Technology Marches On - Plastic Guns

Last Saturday, Defense Distributed successfully test fired a plastic gun manufactured on a 3D printing machine.  The only non-plastic functional part in the weapon is a common nail used as the firing pin.  The files necessary to drive a 3D printer to produce the parts have been posted to the Web.  The gun is called the Liberator, named after the FP-45 Liberator single-shot weapon designed during WWII as an insurgency weapon to be air-dropped in large quantities behind enemy lines.  The announcement brought a considerable amount of criticism from certain parties, most notably Sen. Chuck Schumer (D-NY).  Criticism mostly falls into one of two categories: that anyone, including criminals, can download the files and print off a copy of the parts over the weekend, and that a plastic gun can be carried through airport metal detectors without setting them off.

Home-built single-shot improvised handguns are nothing new in the United States.  The photo to the left shows such a gun, built around a construction stapler.  Zip guns were popular with urban gangs in the 1950s and 1960s despite their rather alarming tendency to blow up in the user's hand.  Zip guns fell out of favor because it became so easy to acquire real handguns.  According to the United States Congressional Research Service, in 2009 there were approximately 114 million civilian handguns in the US.  A conservative estimate is that 3 million new handguns are sold each year, so 125 million seems like a reasonable estimate of the number "in circulation" today.  Unsurprisingly, people who want a handgun really seem to have no trouble acquiring one.

Building a zip gun requires a small degree of mechanical ability.  It's also straightforward for someone with better but still modest machining skills and access to a metal lathe and a couple of attachments (available cheaply at Harbor Freight stores) to build real guns in their garage.  The Sten submachine gun was designed to be manufactured in exactly such settings — one Danish resistance group during WWII manufactured Stens in a bicycle repair shop.  Detailed drawings and specifications for the Stens are readily available, both online and through public libraries.  Even though production of fully automatic weapons is now illegal in the US without a hard-to-get license, some hobbyists still build Stens secretly, apparently for the joy of going far out into a rural area and firing a submachine gun at least once.

Non-metal guns that can pass through a metal detector have been a goal for various secret services and intelligence organizations for decades.  There have been rumors that ceramic and plastic guns have been developed, but none of those ever seem to be verified.  If you watch the video at the links above, the plastic Liberator is quite bulky — not something that you would expect someone to sneak through on their person in a long security line.  The bulk is inherent in the use of plastic — the plastic material is structurally weak, so the components have to be large in order to withstand the pressures generated when a cartridge is fired.  The device would also show up clearly in a luggage x-ray.  Even if the gun were successfully smuggled onto a plane, it's still a single-shot device.  A terrorist gets one shot before the passengers stomp them.

So, if it's easy to get a real gun for use in a non-secured setting, and still very difficult to smuggle a single-shot and not-very-useful plastic zip gun through airport security, what's to be afraid of?  Well, the scenario that concerns me is the bright ten-year-old who downloads the files and prints off a copy of the weapon on their parents' 3D printer, loads it with a high-powered round out of the box that Dad has neglected to lock up, and the weapon blows up in their hand.  Possibly they lose the hand; there's a substantial risk of losing an eye from flying parts; and while less likely, it's still possible that they die.  Or their friends who are watching are injured or die.  I'm willing to entertain a small wager that we see the injured child long before we see an adult making improper use of a printed zip gun.

Texas' Water Woes

For the last few years, Texas has been held up by conservatives as the example for doing the right things to recover from the Great Recession: keep taxes low, eliminate regulations on businesses, make drastic government budget cuts.  They are fond of pointing out that Texas has led the 50 states in job creation over the last few years, with the corresponding population increases.  What they haven't identified is where the water to support all those jobs and people will come from.

The figure to the left summarizes the current status of the ongoing drought in Texas. 70% of the state is categorized as being in severe drought conditions, or worse.  These are not the worst conditions that have occurred in the last few years.  In October 2011, 70% of the state was in exceptional drought conditions, the most serious level in the measurement scheme.  There is a growing body of archeological evidence that, rather than being unusual, the current conditions are actually a return to normal after a century that has been wetter than the historical average.  The drought has appeared in a variety of news stories.


Wichita Falls, a city of about 100,000 people, is the largest on a list of more than 20 cities that could run out of water within the next 180 days.  The city government there describes the situation as "possible but unlikely".  Some other authorities seem less sure than that.

Farmers along the Colorado River (the Texas Colorado River, not the one that carved the Grand Canyon) downstream from Austin have had their irrigation water cut off by the Lower Colorado River Authority. The LCRA gives cities and power plants higher priority access to the reduced amounts of water available.  Lakes Travis and Buchanan, the major Colorado River reservoirs upstream from Austin, are at less than 40% of capacity entering what is typically the hottest, driest part of the year.

Two years ago, Texas filed suit in the US Supreme Court against the state of Oklahoma, demanding that Texas be allowed to purchase a portion of the water that would otherwise flow into the Red River and transport it to northern Texas (and to the rapidly-growing Fort Worth area specifically) by pipeline.  That case was argued before the US Supreme Court this week past.  Most articles described the justices as sounding dubious about the Texas claim on the water.

Earlier this year, Texas filed suit in the Supreme Court against the state of New Mexico, accusing that state of improperly impounding water that would otherwise flow down the Rio Grande to Texas.  If things proceed at their normal pace, this case will be heard in about two years.  As an aside, New Mexico is having its own internal water fights, as farmers with senior rights have made a priority call that would drastically limit the diversions that cities could make.  New Mexico and Texas operate under quite different sets of water law: in New Mexico the long-established farmers have priority, while in at least parts of Texas, farmers are near the bottom of the list.

Various Texas authorities believe that Mexico is failing to meet its obligations for water deliveries into the Rio Grande as set by the "Treaty of the Utilization of Waters of the Colorado and Tijuana Rivers and of the Rio Grande" signed in 1944.  Those authorities are trying to find ways to force Mexico to increase its deliveries.  The International Boundary and Water Commission, an agency of the US federal government with responsibility for negotiating and enforcing such treaties (at least enforcing the US side of things), is not certain that Mexico actually owes Texas more water at this point in time.

Farmers in the Texas Panhandle and other parts of west Texas have been draining the Ogallala Aquifer at an increasing rate.  In response, some water districts in those parts of Texas are imposing withdrawal limits for the first time in history.  Over the last couple of years, restrictions on water withdrawals for the purpose of hydraulic fracturing of oil and gas wells have been imposed on multiple aquifers.

ERCOT, the entity responsible for assuring the reliability of the Texas power grid, has received notice from the national reliability council that Texas does not have the necessary reserve power resources to meet reliability targets.  One of the factors limiting the ability for large new thermal generating plants to come online is the difficulty of identifying sources of water for cooling.  In 2011, multiple Texas power stations came close to having to shut down due to shortages of cooling water.

Probably Just a Coincidence

In the winter, some of us who live along the Front Range of the Rockies (roughly from Casper, Wyoming as far south as Pueblo, Colorado) keep an eye on the mountain snow pack.  That's the water that's going to caught in the reservoirs for use next summer.  A month ago, we were looking at a pretty lean snow pack.  Multiple late-season storms have eased the situation somewhat in parts of the mountains.  Some of the drainages (there's a reason Colorado is sometimes known as the "Mother of Rivers") in the northern part of the state are now above 100% of the 30-year average for the date and all of them are above 90%.  In contrast, the southern drainages, and the southwestern part of the state in particular are in much worse shape.  The Upper Rio Grande is at only 68%; we're not going to be sending much water to New Mexico and Texas this year.  Texas is already busy fighting over water with its neighbors.  The Supreme Court heard a case between Oklahoma and Texas this week.  Earlier this year, Texas filed another Supreme Court case against New Mexico.

This division of Colorado into a relatively wet north and a quite dry south reminded me of another map I had reviewed lately.  This map of North America is taken from the U.S. Global Change Research Program's draft 2013 report to Congress.  This figure shows changes in winter and spring precipitation for later this century under a continued high CO2 emissions scenario (you should be able to "View Image" or similar in your browser to see a larger image).  Blue-green colors indicate increased precipitation, brown shades decreased precipitation, with darker colors indicating greater changes.  Colorado sits roughly in the area where the changes come together -- increased precipitation in the north, decreased in the south, the same sort of pattern that we're seeing in this year's snow pack.

The similarity of the maps is probably just a coincidence.

Odds and ends

Today I'm going to try to pull several bits and pieces together.  Last week I was involved in an interesting on-line discussion about the future of electricity supplies in the US.  One of the positions I took is that areas heavily dependent on coal for generation have a problem: the stuff is steadily becoming less popular politically, where "politically" means "in voters minds."  Several of the people in the discussion made the argument that essentially unlimited cheap natural gas would take up the slack for a very long time.

The EIA recently published a brief piece stating that so far in 2013, use of gas for electricity generation is down significantly from 2012 levels.  The piece attributes the decline to the rising wholesale price for natural gas.  The choice of whether to dispatch coal-fired or gas-fired generation is very sensitive to the relative prices of the fuel.  The EIA piece includes the fuel cost chart shown to the left showing that coal and natural gas prices (measured per MWh of delivered electricity) have recently begun to overlap, mostly due to increasing gas prices.

There have been a number of articles lately (for example, here) that summarize a number of trends that suggest production of gas from tight sources is going to decline, further driving up prices.  Over the last several months, a number of companies with large tight-gas holdings have written down billions of dollars in the worth of those holdings, reflecting lower estimates of the amount of gas that can be extracted, and the price of extracting it.  The number of rigs drilling in the various shale plays has been declining slowly.  Evidence for the rapid decline in production rates from shale gas wells continues to pile up.  I interpret all of this to suggest that the producers aren't making a profit at current prices, so will reduce supplies until the prices are high enough to be profitable.  It would not be surprising if there is a bankruptcy or acquisition or two somewhere down the road.

A recently published Duke University study of the effect of new EPA clean-air standards will drive a shift from coal to natural gas, even though coal may be cheaper, due to the large capital costs of complying with the standards.  Certainly there have been a lot of complaints about the cost of complying with proposed new standards for sulfur- and nitrous-oxides and fine particulates.  One of the points that I often try to make is that such impacts may not be uniform across the US.  The EPA's Cross-State Air Pollution Rule (CSAPR, currently on hold after a federal court decision) only affected states in the Eastern and Texas Interconnects; none of the Western states were affected [1].  In light of the Duke study, the threshold at which the affected generators switch from natural gas to coal may be at a higher price than considered above.

The bottom line on this is, IMO, that for some parts of the country, electricity is going to get steadily more expensive.  In particular, I look for prices in the Eastern and Texas Interconnects to rise more rapidly than prices in the Western.


[1]  There are multiple reasons for this.  One of the reasons is that western states are big on average, with (outside of California) relatively low populations.  Cross-state effects are understandably smaller.  A second reason is that some of the bigger western coal-fired plants have already improved their emission profiles.

But Which Math...?

The League of Ordinary Gentlemen is having a symposium series of posts about higher education in the 21st century.  James K, one of the regular front page authors, put up a post on the question of "Yes, But Which Arts?" with regard to what should go into a degree in the liberal arts.  One of the other regulars expressed the opinion that stopping at College Algebra was sufficient to "conceptually understand higher mathematical concepts, even if you have no idea how to work them."  James disagreed; I disagreed much more strongly.  Stopping at algebra leaves you woefully ignorant of almost all of the powerful ways that math can be used to think about the world.

I admit to being prejudiced on the subject: I'm an applied math guy and have spent essentially all of my adult life using math as a tool to think about the world.  Not the only tool, but an important one.  Several of the other commenters display their own prejudices (in the non-derogatory sense of that word).  Some advocate learning at least one, if not two, foreign languages.  Some emphasize philosophy.  Some English Lit.  I found the number of different reasons for including English Lit to be interesting, since they covered a gamut from analysis to composition.  I'm absolutely an advocate of a composition requirement, but would prefer for it to be done absent the literature component.  My high-school composition class was enormously valuable: writing every day, with requirements to write a variety of things, and feedback on what you had written.  If pressed, I'm on the side that says no one should be allowed to graduate with a four-year undergraduate degree without taking such a class.

James' question prompted me to think about what math material should a well-rounded college education include?  To put limits on things, I assumed six semester-hours, and six topics to be covered.  I also assumed a mastery of algebra as a prerequisite, on the theory that anyone starting a four-year degree program without that much high-school math is deficient.  In no particular order, here's my first cut at a list of six topics.

• Enough probability to understand why my favorite bar bet is a sucker bet: We'll go around this crowded bar and ask people their birthdays (month and day, ignore the year).  I'll bet that at least some two of them will have the same birthday.  Loser buys the next round.  If you take me up on it, I'll be buying less than a third of the time.  Why?

• Enough statistics to understand that all of the questions you should be asking involve "What's the distribution?"  In the real world, descriptive statistics almost always provide an incomplete picture; you want to know about the distribution.  If there are 30 people in the bar, and one of them is Bill Gates, asking questions about wealth and income really do require you to know about Bill.

• Enough differential calculus to understand basic optimization.  I'm not particularly concerned about whether or not you can solve the problems; can you set them up?  An individual license for Mathematica doesn't cost much more than a high-end graphing calculator.  In addition to doing everything that the calculator can, Mathematica is also far better at taking derivatives or integrals than you or I will ever be.

• Enough integral calculus to understand the "infinite summing up" aspect.  I've always felt that this was the important aspect of the integral as applied to real life.  You can answer an enormous range of "how much" questions this way.

• An introduction to something like discrete dynamic systems, including feedback loops.  I think that sort of thing is much more accessible than writing systems of differential equations.  For some of the packages implementing this type of discrete model, there are graphical tools that help put things together.

• Finally, a module on graph theory with an emphasis on algorithms.  A lot of graph theory problems are "non-math" math -- no numbers involved at all.  I think it's important that non-mathematicians understand that math doesn't have to be just about numbers.

SCOTUS Predictions and Same-Sex Marriage

Yesterday the Supreme Court of the United States (SCOTUS) heard arguments regarding California's Proposition 8 (the amendment to the state constitution that made same-sex marriages illegal in California).  Today the Court heard arguments on the constitutionality of one portion of the federal Defense of Marriage Act (DOMA).  Lots of Internet discussion about what all the questions and comments asked/made by the justices meant.  I see the problem somewhat differently than most of what I've read: in some fashion, Chief Justice Roberts needs to find a majority (or majorities) that will produce coherent consistent decisions about three things: DOMA, Prop 8, and the fact that several states have now passed laws allowing same-sex marriage.  The last one wasn't argued in either of this week's cases, but it's still a pretty big elephant in the room.

To start, why do I think the burden is on Roberts?  My perception is that he is desperate to avoid going down in history as the Chief Justice under whom the SCOTUS became a blatantly partisan beast.  He voted with the four liberal justices for a strained compromise over the Patient Protection and Affordable Care Act (PPACA) last year.  I also have another opinion about the Chief Justice: whatever the decision, he wants it to benefit big corporations.  The PPACA decision certainly seems to provide benefits to large business interests.  Big insurance gets millions of new policy holders.  Big hospitals get reimbursed for what has been until now charity care (the remaining states will come around on the Medicaid expansion when the hospitals lean on the governors and legislators hard enough).  More insured patients has to be good for big pharma.  And it is at least the beginning of the light at the end of the tunnel for employers no longer having to provide employees with subsidized access to group health plans.

So, where does the large corporate interest lie in same-sex marriage?  The only one that comes immediately to mind is consistency in treatment of marriage from a benefits perspective.  As part of a corporate acquisition, I retired from a large company for which I had never actually worked.  That company acquired, along with the instantly-retired me, legal obligations to provide a variety of retiree benefits to me [1].  These obligations are quite different than those the company provides to its own long-term employees who retire.  Human resources absolutely hates the small group of us who receive special treatment [2].

If that's the corporate interest, then the outcome will be Roberts and the four liberal justices ruling in the two cases that the 14th Amendment's equal protection clause makes it improper to treat same-sex couples any differently than different-sex couples with respect to civil issues.  The federal government, state governments, and employers will be required to recognize same-sex couples as "married" couples.  Can't leave the decisions up to the states if the goal is HR consistency; and probably can't outright ban same-sex marriages because of the partisan thing. Religious organizations will be allowed to pick and choose the couples for whom they will perform a ceremony (as they do today), but will be stuck with the same kind of situation they're struggling through over abortion and birth control when they act as an employer in the civil sense.

The other four justices will just be stuck writing whiny dissents.


[1] As an aside, most of those obligations had followed me through three previous corporate reorganizations.  The original plan terms were broadly set by a company that had long since ceased to exist.  A few other things had been tacked on as the plan and I (and the people in the same situation) moved along.  Most of those add-ons were attempts to make retirement attractive enough that we would take it.

[2] Hate as an organizational thing.  The human-resource representatives with whom I have interacted over the last decade have been uniformly courteous and helpful.  It's just that instead of being able to be helpful immediately, it sometimes takes several days because they have to go research if and how my special status changes the normal answer.  Even longer if they have to go get an opinion from the legal staff.

Energy-Economics Models

Dave Summers at Bit Tooth Energy comments on ExxonMobile's new Outlook for Energy publication (PDF). I particularly like his last paragraph:

If I can put it another way. At the beginning of the report, after projecting a reasonable estimate of global growth over the next 25 years, EM put in a very optimistic level of improvement in energy efficiency in order to significantly lower energy demand. Then, to balance supply to that lower level of demand, they seem to have picked the most optimistic of assumptions about potential growths in that supply. I rather suspect that they are seeing the writing on the wall, but obfuscating it with optimism beyond the bounds of realistic expectation.

I want to write briefly today about dividing various energy-and-economics forecasting models into two camps.  The ExxonMobile model falls into the first camp, as do the models used by the EIA and the IEA.  The basic structure of these models is to: (1) assume a global economic growth rate (2.8% per year in ExxonMobile's case); (2) calculate the amount of energy required to support that growth; and (3) allocate the necessary energy production across various sources.  As Dave points out, one of the sources ExxonMobile has depended on heavily in this year's forecast is energy efficiency.  Despite those improvements, the 2040 forecast when compared to 2010 figures calls for a 30% increase in global liquid fuel consumption and an 85% increase in global electricity consumption.  Models in this camp are optimistic: they predict continued rapid global economic growth for the duration of the time frame they examine.

Call the second camp the Limits to Growth models, as that one is probably the best known.  These models work in the reverse direction from those in the first camp: (1) estimate the resources that are available; (2) estimate how effectively those resources can be used; and (3) calculate the economic growth (either positive or negative) that results.  Other models in this group include those done by Robert Ayres and Benjamin Warr.  In the Ayres-Warr models, the critical resource is high-quality energy.  The models in this camp are quite pessimistic about the future: pretty much all of them predict a global economic collapse of some sort within a few decades (some sooner than others) as population outgrows a shrinking resource base.

Given the drastic differences in the predictions, it seems reasonable to ask how well the two camps have done at forecasting the future.  The figure to the left [1] compares the standard run of the model published in Limits to Growth in 1972 with actual data from the 30 years following.  The pastel solid lines from 1900 to 1970 are the historical data that went into model; dotted lines are the results from the standard run; and the bold solid lines from 1970 to 2000 are estimates of how the variables actually changed over those 30 years.  The predictions have held up quite well.  Non-renewable resources have not declined as rapidly as predicted, and food-per-capita has grown somewhat faster, but the differences are still relatively small.

The models in the first camp have, IMO, not done nearly so well.  For example, it has become sort of an annual tradition in some forums to compare the IEA's forecasts to what actually happened over time (and make fun of the predictions).  For example, in the IEA's World Energy Outlook 2001, they forecast that conventional oil supplies should be adequate to meet global demand through at least 2020. They predicted that in 2010 demand would be 96 million barrels per day at a price of $21 per barrel, increasing in 2020 to 115 million barrels per day at a price of $28 per barrel.  Looking back from today, we know that conventional oil production peaked at around 75 million barrels per day around 2004.  Total liquid fuels production in 2010 (conventional oil, plus unconventional oil, plus natural gas liquids, plus biofuels including ethanol) was about 87 million barrels per day.  As I write this, the price for Brent crude is above $107 per barrel.  Oil prices below $30 per barrel appear to be gone for good (well, absent a very large global economic collapse): this past week, the oil ministers for Saudi Arabia and Kuwait said publicly that $100 per barrel is a reasonable price for oil.

So the pessimists appear to be winning.  I admit to being a pessimist, but not as much of a pessimist as the Limits to Growth group.  The reason I'm not that pessimistic is because I think looking at global numbers is not the right way to do things.  Different regions have different characteristics, with different population growth rates and different endowments of both renewable and non-renewable resources.  As limits on the availability of liquid fuels make the world a bigger place, those regional differences will matter.  Collapse in one region need not spill over into other regions.  I really need to put time into building my own model, where it's possible to look at the projected outcomes for specific regions of my own choosing.


[1] The figure is taken from the Smithsonian.com web site piece titled "Looking Back on the Limits to Growth".