feb 2007 / greg goebel
* Entries include: power grid infrastructure, short history of life, MySpace fakery, Hillary for president, ZUMWALT destroyer, global warming lawsuits, pythons in Florida, automotive black boxes, Iranian oil drought, traffic roundabouts in Canada, tracking spam, Chinese ecopolis, bizarre warning labels.
* FAKING IT ON MYSPACE: The MySpace social-networking system has made a splash over the last few years, and also created controversy over a supposed rash of sexual predators infesting the site. According to an essay on the MIT TECHNOLOGY REVIEW website by well-known computer columnist Wade Roush, the scandal over MySpace seems to be exaggerated. MySpace has over 116 million subscribers, more than the population of Mexico; the incidence of sexual solicitation on the system is low, and the company is working to give the boot to nuisances. Surveys show that there is a fair amount of peer-to-peer sexual solicitation on the MySpace, but most of the time the recipients simply ignore it.
Rousch claims that the real threat of MySpace to commercialization. Since 2005 it's been owned by Rupert Murdoch's News Corp, which means a focus on the bottom line. Any operation with 116 million clients is going to have marketing clout, and Google has recently inked an exclusive agreement with MySpace to provide search capability and targeted ads on the system.
That MySpace wants to make money is no cause for complaint, but the business model is suspicious in some respects. MySpace was established as a social-networking system in which people set up profiles for themselves for communications and other interactions. The basic concept was derived from earlier social-networking systems such as Friendster, with the profiles containing a user's personal text, photos, videos, and so on, as well as a list of contacts or "friends" and feedback from said friends. MySpace differed somewhat at the outset at being friendly to independent artists like musicians, photographers, digital filmmakers, and the like, giving them a forum to promote their efforts. A band, for example, could provide profiles of its members, publicize concerts, and upload tunes; filmmakers could upload video trailers.
In the early days of the Friendster system, only an individual could set up a profile, but this was clumsy for, say, a band trying to get recognition, and so the company relented, allowing "fakester" profiles to be set up. People also liked to set up fakester profiles for fantasy characters or a pet, and users accepted it. MySpace accepted fakester profiles from day one, and has in fact has taken the idea farther. Now it's easy to set up a profile for a company, a movie, a TV show, new products, and so on, with Pepsi and Burger King having their own fakester profiles -- Burger King's profile had 135,000 friends as of October 2006.
MySpace users go along with this because such brand-affiliation linkages help establish an online identity for a user, listing the cool products a particular user likes. The difficulty is that the system then starts to look less like social networking and more like a highly targeted marketing research system, in which businesses can obtain as elaborate a set of statistics as desired on the customer base, and on the other hand be able to target advertising down to the individual level.
To be sure, as most Amazon.com shoppers know, a "smart" advertising system is a nice thing to have, providing tipoffs to desireable products -- advertising ceases to be a nuisance when it actually promotes products that are interesting. The problem is, as Roush points out, is that MySpace was not designed at the outset to be simply an advertising medium, it was designed to get people together. In turning into something not so different from a TV shopping channel, MySpace may be laying the seeds of its own ultimate irrelevance.
* THE HILLARY QUESTION: When Bill Clinton left the office of president of the United States in 2001, even many of those who had voted for him breathed a sigh of relief, being glad to be done with the personal scandals he had brought down on himself. Those who had hated him all along were downright gleeful to see his backside, and they were at least as glad to see the last of his wife Hillary -- seen as pushy, ambitious, frosty, calculating, elitist, and too much the embodiment of loose-cannon liberalism. Goodbye, Bill and Hillary.
Now New York Senator Hillary Clinton has declared she's in the running for president: Hello, Hillary and Bill? As reported by THE ECONOMIST's American columnist Lexington ("Hating Hillary", 27 January 2007), to absolutely no surprise the Hillary haters are now coming back out of the woodwork, selling Hillary-bashing mugs and T-shirts and writing books accusing her of everything from fascism to leaving the toilet seat up. Such was exactly predictable; the question is: what of it?
The track record of Senator Clinton has demonstrated a person with her eye focused on the prize. Like Hillary Clinton or not, nobody ever sensibly claimed she was stupid or lazy, and she has carefully, methodically trimmed her sails to the centrist line. A bank robber was famously once asked why he robbed banks; he replied "because that's where the money is." A smart politician similarly knows that the center is where the votes are. Senator Clinton has been carefully establishing links with conservative colleagues on issues of common concern, treading carefully on abortion, denouncing flag-burning -- and has been a solid supporter of the war in Iraq. Indeed, she has been so diligent in cultivating her connections to the military community that when she spoke at a meeting of military officers there were worries ahead of time that some of the audience would walk out -- but they gave her a standing ovation instead. Some conservative politicians who once abused her have made retractions, unusual in itself in today's polarized political climate.
No matter what she does, however, there is a large and loud faction that hates her, both for herself and for her husband. The extreme left has also not been happy with her cultivation of the center, in particular for her backing of the war in Iraq. She has been booed at left-wing rallies and antiwar activist Cindy Sheehan has compared her to rightist talk-show host Rush Limbaugh. However, Democrats who are still interested in reality are now coming to realize that she was never quite the left-outfield boogeywoman the conservatives had painted her to be. Even her much-despised health-care plan had support of businesses, she was for welfare reform, and she is a practicing Methodist.
How much will Hillary hatred cost her? As far as the extreme left goes, not much. If she were running against George W. Bush, the only alternative they would have would be to vote for Ralph Nader (again!) It is of course very hard to believe that the Republicans will offer a candidate with approval ratings as low as those of the current resident of the Oval Office, and no matter who wins the next election it is just as difficult to believe the new president won't be trying to put the Iraq fiasco to bed, rationalize the war on terror, embrace environmental issues in a more wholehearted fashion, and perform more effective international diplomacy. After all, no candidate who didn't is going to win. However, still, will the extreme left vote for a Republican? Not likely.
The issue with the hard-core conservative Hillary haters has the virtue of being simple: they will, as the saying goes, vote for a dead yellow dog before they'll vote for Hillary. There aren't enough of them to prevent her from winning by themselves, but they could swing the vote. At the same time it is hard to believe their hatred will sway anyone else. The only people who take any of the rabid Hillary-bashing books seriously are people who already believe it all anyway; as far as everyone else who reads any such book go, the only message they walk away with is that the author is a nut.
In fact, Hillary hatred may actually hand her votes. One of the things that provokes the Hillary haters is that she is a successful, powerful professional woman -- and attacking her even implicitly on that basis will drive many women voters to her side. Indeed, given the fact that the Hillary haters vent their detestation without a moment's thought of who it alienates, Senator Clinton may find their venom has a silver lining.
Senator Clinton is certainly used to being attacked, and knows how to both defend herself from attacks as well as how to turn attacks to her advantage. It's one of the advantages of being calculating. She has a powerful network of contacts and a massive campaign chest. If her husband is, to say the least, something of a mixed asset as far as public appeal is concerned, he is extremely well-connected, and nobody ever claimed that Slick Willie Clinton wasn't a very shrewd political operator. He also has experience in running two successful presidential campaigns.
That does lead back to the notion of Bill Clinton as the prince consort in the White House, an idea that inspires discomfort even among some who think Hillary might well be given her chance. However, the real issue is Hillary Clinton herself. Pushy and ambitious? Yes, but who gets to the White House who isn't? Cool and calculating? After the conviction politics of the current administration, maybe that doesn't seem like such a bad thing.
* A SHORT HISTORY OF LIFE (7): The Silurian period, beginning 435 million years ago, picked up where the mass extinction of the late Ordovician left off. Although the trilobites had suffered badly, they survived, to be joined by another class of arthropods, the "euryptids" or "sea scorpions". They weren't scorpions as we know them, being more closely related to horseshoe crabs, but they did have scorpionlike whip tails -- along with big lobsterlike claws. The sea scorpions are now seen as the "signature" creatures of the Silurian, attracting attention because of their large size, up to over a meter and a half (about five feet).
They were the biggest arthropods ever. It's not hard to see why arthropods never got any bigger, since the requirement that they molt their external exoskeletons is troublesome, and it gets more troublesome as their size increases. When competitors became widespread later, the penalties of molting would cut arthropods back down to size; the biggest we have today are the king crabs. In any case, the sea scorpions shared their environment with aquatic true scorpions -- a peculiar notion, since these days all scorpions are land animals.
At the beginning of the Silurian, the fish were along the same lines as they had been, with armored heads, no jaws, no skeletons, and simple tails for swimming -- though they did become more dartlike and hydrodynamically efficient. The fossil record seems to indicate they were more widespread. Late in the Silurian, "cephalapsids" arose that featured a significant innovation of left and right control fins, providing greater agility in swimming. The late Silurian also saw the introduction of the first "gnathostomes" or jawed fishes, a significant development: they would ultimately push the agnathans into their modern niche existence.
Later in the Silurian, scorpions and some other arthropods ventured out onto land. Plants began to make an appearance out of the sea, though the forms were primitive, lacking leaves, some along the lines of the cactus but lacking spines -- there wasn't much around to graze on land plants in those days, why would spines be needed? They did feature, however, a semi-rigid structure to allow them to stand upright, as well as "vascular" system to transport fluids and nutrients, a distinct change from the limpid sea plants that came before them. [TO BE CONTINUED]
* INFRASTRUCTURE -- THE POWER GRID (3): The power grid that drives electricity across the country is clearly hierarchical, with big power towers carrying AC electricity from power station switchyards, and the power ultimately passed down through city electrical networks to end users like ourselves. The hierarchy of the system is also reflected in higher voltages. Residences use 120 VAC, but the big trunk lines operate at hundreds of thousands of volts. The reason this is so requires another discussion of electrical theory.
All conductors -- in this case, the power lines -- have a certain small resistance of their own. Imagine having the same simple circuit given in earlier installments, with a voltage being driven across a resistive load. Now factor in the resistance of the wiring. If the resistance of the wiring is the same as the resistance of the load, then half the power will be lost in the wiring and won't be available for use in the load.
One way around this is to increase the load resistance. What this does is increase the resistance of the circuit as a whole, meaning that for a given voltage there's less current. Given a constant conductor resistance and less current, that means less power wasted in the conductor resistance. However, load resistance is something of a given, and it's not possible to just change it to whatever is needed. There is, however, a magic trick to make its resistance seem larger. That trick is called a "transformer".
As explained previously, an inductor consists of a coil of wire wrapped around a core. Now imagine wrapping a second coil around the same core. If a current is forced into the original "input" coil, it creates a growing magnetic field; this growing magnetic field then creates an electric current in the second "output" coil. This only works with AC, by the way, since with DC, once the current's stabilized in the input coil there's no changing magnetic field to create a voltage in the output coil.
This might seem pretty useless in itself, but suppose the second coil has ten times as many loops as the input coil. The changing magnetic field now cuts across tens times as many loops and the effect is that the output coil has ten times the voltage. Of course, there's no way to get something for nothing, the power has to remain constant, and so the current is cut to a tenth to compensate.
Now take the simple example circuit, but with the input changed from a DC voltage source to an AC voltage source and then run through a "step-up" input transformer to increase its voltage by a factor of ten for transmission through the circuit. On the output side, the load is connected to a "step-down" output transformer that converts back down by a factor of ten, resulting in the original voltage. From the circuit side of the output transformer, the voltage appears ten times as great while the current appears ten times smaller -- meaning the load resistance appears a hundred times greater. This reduces the current in the circuit and so reduces the power lost in the conductor resistance. Some sources seem to imply that high voltage in itself is responsible for the improved efficiency, but though that's not wrong as such, it's not particularly helpful in making matters clear.
The original electric power distribution system was invented by Thomas Edison and used DC, which won't work with a transformer and could only be distributed at low voltages. George Westinghouse realized the virtues of high-voltage AC and pushed it as a competing system, leading to a bitter war between the two men. Edison insisted that high-voltage AC was inherently unsafe -- it has its hazards, nobody with any sense gets close to a downed high-voltage line -- but his DC system was doomed by its inefficiency. The risks of high-voltage AC proved manageable.
By the way, early US power plants ran at 25 Hz, not 60 Hz. There was a push early on to standardize on 50 Hz, but US electrical equipment makers pressed Congress to legislate 60 Hz here as a trade protection measure. Some early US electric trains ran on 25 Hz power and 25 Hz subnets linger here and there, as does 16 2/3 Hz in Europe. Aircraft and space systems run on 400 Hz; the reason is that transformers get smaller as the frequency gets higher, and the lighter transformers are a big plus on aircraft.
* Not so incidentally, electric power is typically transmitted by triplets of cables, not just two. The problem with AC as just described is that it doesn't make very effective use of the wiring, varying between a peak and zero. In practice, electricity is produced in three "phases", staggered by 120 degrees, with each phase transmitted over two of the three cables, making better use of the wiring. Some industrial equipment will actually use three-phase power, but for general residential use a single phase is "tapped off" from two of the wires.
[TO BE CONTINUED]
* GIMMICKS & GADGETS: According to a comment on a WIRED Online blog, vending machines are starting to go upscale: it is now possible, in large airports, fancy hotels, and the like to buy iPods, headphones, and other electronic gadgets with costs a few orders of magnitude more than normal vending-machine fare with the swipe of a card. It seems the concept has proven very successful, though the iPods of course are delivered with no music or video on them. The next step is to add a music-download kiosk -- just plug in your shiny new iPod and download away. Incidentally, the iPod doesn't fall down into a delivery chute with a CLUNK -- a little mechanical arm grabs it and hands it off in a more considerate fashion.
* A correspondent tipped me off to an interesting operation named "ReVend" that sells ... get this ... "reverse vending machines". They might better be called "smart trashbins", being used to recycle certain specialized discards -- recyclable glass bottles, plastic bottles and cans, and so on -- and providing a payout to the user. They do look have vending-machine cosmetics; it appears they are intended to support vending-machine kiosks.
* Pocket memory modules with a USB interface and a capacity of a gigabyte or two are now commonplace. Disk drive maker Seagate is now trying to do them one better, with a series of "FreeAgent Pro" pocket disk drives with capacities ranging from 320 gigabytes to a whopping 750 gigabytes of data. The drives feature a modular interface system that can accommodate a USB, serial ATA, or dual Firewire link. Prices range from about $200 USD to $420 USD.
Seagate also offers a "FreeAgent Go" series, in a slimline package with a fold-out USB interface and capacities ranging from 80 to 160 GB, for $130 to $190 USD, and even a matchbox-sized USB "FreeAgent Go Small" with 12 GB for $140 USD. The idea is that instead of lugging a laptop PC around, a user can just carry the pocket drive and plug it into the USB port of any handy PC. Obviously this is an idea that would work better if the drive also included a resident software suite, but for now all the modules carry is some data-management software.
* As the saying goes, everything old is new again, and an article on MIT TECHNOLOGY REVIEW Online surveyed a new cyberfad: functional replicas of personal computers from the early days.
For the real hardcore nostalgics, VintageTech sells a clone of the Digital Electronics Corporation's PDP-1 minicomputer. Although it's easy to find PDP-1 software emulators online and the clone is powered by Linux under the hood, the product gives the perfect look and feel of the real thing, allowing the user to "vatchen das blinken lites", as they used to say. It can be used to run SPACEWAR!, the very first two-person computer game, developed by MIT computer scientist Steve "Slug" Russell in 1961.
For those who don't want to go back that far, there's the "Replica 1", a clone of the 1976 Apple I, for only $160 USD. It's not a perfect clone down to the layout of the circuit boards, but it works the same. Those who want their nostalgia but still want to keep their computing power can opt for the Briel Computers AltairPC, which is just a case that makes an ordinary PC look like a MITS Altair, regarded by some as the machine that started personal computing. Download a MITS Altair emulator and it's hard to tell the difference.
* STEALTH DESTROYER: World War II destroyers were intimidating in appearance, bristling from bow to stern with turrets and guns and littered with antennas. As reported in POPULAR SCIENCE ("Invisible Warship" by Gregory Mone, November 2006), the US Navy's latest destroyer, the "DDG1000 ZUMWALT", the first new Navy destroyer design in three decades, is about as featureless as a surface warship could be thought to be, with inward-sloping sides rising seamlessly up into a superstructure in the shape of a truncated wedge, containing the bridge, planar radar and communications antennas, and even the smokestack.
The 183 meter (600 foot) long ZUMWALT has been designed for shallow water "littoral" warfare, the Navy not expecting a fight on the high seas these days. The blocky shape of the vessel helps reduce its visibility to radar, with the buried smokestack reducing the ship's infrared signature. The engine room is lined with soundproofing to reduce the acoustic noise signature. The ZUMWALT will be able to get in close to shorelines to dispatch SEAL commandos on assault boats, or on helicopters operating off the flight deck in the rear.
SEALS will receive fire support from the ship's armament after going in. There are two turrets forward, each with a single automatic 155 millimeter gun, and two small turrets aft, each with a single 57 millimeter gun. The 155 millimeter guns will be able to fire rocket-boosted GPS-guided shells at a high rate of fire, giving them long-range punch. For deep strike, antiship attack, or anti-aircraft defense, the vessel carries a real punch with 80 vertical-launch missile silos lining the forward turrets and the aft flight deck.
The ZUMWALT's sophisticated dual-band phased-array radar will give a comprehensive view of the threat environment from the surface to the air to the horizon, capable of cutting through countermeasures and rough seas to spot small targets. The reversed-sloped bow ends in a bulbous underwater nose containing a sophisticated sonar array. Construction of the ZUMWALT is expected to begin in 2007, with the ship commissioned in 2012. Six other members of the class are planned.
* CO2 LAWSUITS: According to an article in BUSINESS WEEK ("Global Warming: Here Come The Lawyers" by John Carey and Lorraine Woellert, 30 October 2006), the rising tide of concern over global warming is now starting to reach into US courts. After the destruction wrought by Hurricane Katrina on the US Gulf Coast in late 2005, some lawyers among the affected decided to take action. Since oceanic storms are produced by warm ocean waters, and global warming is increasing the temperature of the seas, they believe they have a case against industries whose carbon dioxide emissions have contributed to global warming. They are now suing a group of oil companies, coal companies, and utilities for damages.
This may sound bizarre, but it's not a completely unique case, there being over a dozen suits over climate change in the queue for US state and federal courts. It is one of the more extreme -- others involve a suit by the state of Massachusetts against the US Environmental Protection Agency (EPA), charging that the organization needs to work harder to clamp down on emissions, plus a suit being pressed by several Texas cities challenging power plants being planned by utilities, saying the plants don't do enough to cut down emissions. From that angle, the new crop of lawsuits is more focused on persuading the government to take global warming more seriously than it is a hunt for damages.
Some legal efforts along this line -- attempts by cities to hold gunmakers liable for damages due to shootings and crime, and by African-Americans to obtain reparations from slavery -- have been thoroughly shot down, but some, particularly the legal attacks on Big Tobacco, have been only too successful. Payouts over tobacco lawsuits have reached $300 billion USD and the companies have been legally forced to change the ways they do things. Even when the suits get shot down by the courts, the legal pressure often does have an effect on the targets.
Companies that are possible targets of global-warming lawsuits are taking the threat seriously, establishing joint operations for legal defense; some are also doing what they "reasonably" can to reduce emissions and lower their legal profile. Still, some of the plaintiffs have a formidable challenge to get their lawsuits into, much less through, the courts. In particular, the chain of culpability for damage by Hurricane Katrina is extremely flimsy and easily challenged, and the courts have been gradually becoming less open to dubious lawsuits.
However, the lawsuit of the state of Massachusetts against the EPA, based on the state's interpretation of the Clean Air Act and perception that the EPA hasn't been enforcing it, has plenty of legal substance. Ironically, if the state wins, it will cut the ground out from underneath other lawsuits by establishing culpability for the EPA. Other lawsuits seem more muddled: when the state of California tried to pass strong auto emissions regulations, auto manufacturers sued, with the state then pressing a countersuit against the car companies for their emissions. It would seem like a script only a lawyer could love.
* ED: One of the amusing aspects of this scenario is considering that since people exhale CO2, every individual could in principle be sued. I recall Walt Kelly's POGO comic strip, during a period where the inhabitants of Okefenokee Swamp were debating the fact that pollution was caused by people breathing. At one point two of the characters were on their way to visit the local undertaker, a vulture named Sarcophagus Macabre; one character says: "So, where does this vulture stand on the issue of people breathing?" The other answered: "Vultures are usually in favor of those who don't." The final, famous conclusion of the debate was: "We have met the enemy and they is us!"
* A SHORT HISTORY OF LIFE (6): The Ordovician period, beginning 505 million years ago, brought a number of new actors onto the stage. One of the most interesting were the first real fishes.
Actually, it might be more accurate to call them "more or less real" fishes, because they certainly didn't look like any fish we might find today, since they didn't have jaws and had heads covered with bony plates. Such "ostracoderms" were likely slow-moving bottom feeders, cruising along at a slow pace -- with all that bone, they couldn't manage much speed -- vacuuming up food whole for digestion. They had a tail but no auxiliary control fins. Some "agnathans" (jawless fishes) survive today -- both eel-like, the scavenging hagfishes and the parasitic, rasp-mouthed lampreys -- but if the idea of a "living fossil" is inexact in general, it's particularly inexact in the case of these two, since the early ostracoderms had little resemblance to them.
The real "lords of the sea" at the time, at least as far as we can tell now, were the "nautiloids" -- a set of members of the family of "cephalopod" molluscs, which include the squid and the octopus. The nautiloids survive today as the chambered nautilus, which has a spiral shell plugged by a set of tentacles, with an eye on each side of the base of the bundle. Back in the Ordovician, some of them had straight shells, which likely made it easier for them to swim -- cephalods swim by jetting water through a siphon, with the result that the move "backwards", with the tentacles at the rear. One straight-shelled species had a shell 3.5 meters (13 feet) long -- making them the biggest known animals of their era. Nautiloids were actually known from the Cambrian, but they were smaller and apparently not all that common, coming into their own in the Ordovician.
The Ordovician also saw the emergence of the "echinoderms" lower on the food chain, a phylum now including starfishes, sea urchins, sea cucumbers, and crinoids (AKA "sea lillies" or "feather stars", which are sessile filter-feeders). From the looks of them the echinoderms might be thought to be radiolarians, but looks are deceiving: they are born as bilateral larva that generally curve around one side as they grow to form a five-sided symmetry. There were also "bryozoans", creatures that superficially resemble corals but which are a different phylum.
As with the Cambrian, there was no life on land during the Ordovician. Processes of continental drift continued, possibly affecting the climate. Whatever the causes, the climate at the end of the Ordovician did change drastically, with a severe drop in sea levels and another ice age. The number of species that died out in that time is estimated at about 20%. This was the first "mass extinction" in the history of life. It wouldn't be the last. [TO BE CONTINUED]
* INFRASTRUCTURE -- THE POWER GRID (2): The previous installment in this series described basic "direct current (DC)" circuit concepts, as well as the concept of "resistive" loads. However, although battery-operated gear and cars run off of DC, the power grid is "alternating current (AC)". In AC, the voltage is varying all the time in a cyclical fashion, in the form of a sine wave. In the US, the standard power-line frequency is, as mentioned, 60 Hz, while it is 50 Hz outside of North America.
The voltage varies from a maximum of +170 volts to a minimum of -170 volts, but the AC line voltage is actually given as 120 "volts AC (VAC)". This is actually the "root mean square (RMS)" value of the sine wave, or in other words the square root of the square of the average value of the waveform. This is the value that will give the proper conversion of the AC voltage into watts when it's put across a resistor. In fact, using RMS values, everything said about the DC circuit in the previous installment in this series is true for an AC circuit. Put 6 VAC across a 100 ohm resistor, the current is 60 milliamperes, and the power dissipation is 6 * 6 / 100 = 360 milliwatts.
However, AC circuits can involve two other classes of loads besides resistors: capacitors and inductors. A simple capacitor just looks like a pair of plates that are separated by a gap, with a wire lead to each plate. Connect a battery to it, and it will store a charge proportional to the size of the plates and inversely proportional to the gap between the plates. Put certain types of nonconductive "dielectric" materials, usually various kinds of plastics, between the plates, and the charge storage or "capacitance" is multiplied by the "dielectric constant" of the dielectric.
A capacitor can be used in a DC circuit, placed in parallel with a load to provide a "surge tank" of electric charge when it's needed. A large capacitor is generally used in DC power supplies in a PC or the like to perform this task. Of course, placing a capacitor in series with a load in a DC circuit is silly -- after the capacitor charges up, no more current flows through the circuit.
An inductor simply looks like a coil of wire, often looped around a core of iron or an iron-based compound called "ferrite". One of the basic rules of electricity is that a current flowing through a wire will generate a magnetic field. Switch a current through a wire and a compass will be turned by it. The other basic rule is that if a changing magnetic field is passed over a wire, it will set up a voltage in it. Switching a current into an inductive coil causes a growing magnetic field that cuts through the loops of the coil, creating a voltage that resists the current. This is called a "back-EMF". Once the current is stable, then shutting off the current flow causes the magnetic field in the coil to collapse, creating a voltage that tries to keep the keep the current going. This current will easily arc across a gap, which is how a classic automotive distributor / spark plug system works.
An inductor is said to be something like the electrical equivalent of a flywheel. The faster the change in current, the greater the back-EMF, which means that an inductor tends to block out high-frequency noise. This is why it's common to have cylindrical ferrite slugs or "chokes" on various types of cables used on computer gear and the like -- the choke makes sure high-frequency noise won't make it through the cable.
A full description of the operation of capacitors and inductors in AC
circuits would be too difficult to consider here, and it's not necessary. A
few simple considerations will suffice. In an AC circuit, a capacitor in
series will not act like an open circuit -- it will act like a load that
obeys ohm's law, except that instead of resistance it provides a "capacitive
reactance" or:
capacitive reactance = voltage / current
An inductor will similarly provide an "inductive reactance". In both cases,
the reactance differs from a resistance in that no energy is dissipated --
it's stored during one part of the cycle and released in the other. This
implies that voltage across and current through a capacitor or an inductor
are not in phase -- and (just take my word for it) -- the phase difference
for a capacitor is in the opposite direction of that for an inductor, or in
other words if a capacitor and inductor of the appropriate relative sizes are
placed in a circuit together, they can cancel out and the overall circuit has
current and voltage in phase.
Generally, when considering the power grid, it's not necessary to worry much about capacitive or inductive loads, since the whole thing can be generally modeled in a simple way as a resistive circuit, but there are some features that would be hard to understand without a little knowledge of them. [TO BE CONTINUED]
* SLITHER: Visitors to the US Southeast quickly become aware of a green vine named "kudzu" that carpets the landscape. It was a Japanese import that found the climate there to its liking and decided to take over. According to a brief article in THE ECONOMIST ("Burmese Days", 2 December 2006), a patch of the South, the great swamp complex of the Everglades in Florida, is dealing with a less pervasive but somewhat more alarming invader: the Burmese python.
Nobody's quite sure how the damn things got there, the assumption being that they started out as exotic pets that got loose, but over the last few years they have been increasing in number and size, occasionally making meals of pets of Miami residents. The snakes like the Florida climate and breed quickly, making them a particular threat to the wildlife of the Everglades.
Wildlife authorities are trying to exterminate the snakes and have come up with a few ingenious tricks. One is to catch female pythons, tag them with radio transmitters, and release them, in hopes of tracking them to nesting areas. Another scheme is to use female python pheromones -- odors produced at breeding time -- to trap male snakes. Dogs are being trained to track the pythons as well. The Florida legislature is considering new regulations to handle the threat, for example requiring permits to own such creatures -- though some suggest the pythons should be simply banned, period.
* ED: After reading this little article I had to double-check the date on the magazine to make sure it wasn't April 1st -- THE ECONOMIST has a tradition of April Fool's articles. It brings back a little nostalgia for THE X-FILES: "Mulder, you can't honestly believe that the cultists were eaten by pythons, can you?" "The truth is out there, Scully."
* AUTOMOTIVE BLACK BOX: Everybody's familiar with the fact that cars generally have computerized boxes under the hood. What everybody isn't so aware of is that, according to TIME ("Psst, Your Car Is Watching You" by Margot Roosevelt, 14 August 2006), such boxes could be used to provide evidence to legally incriminate drivers.
About a third of the cars on the roads of the USA, and about two-thirds of the new cars being sold here, contain "event data recorders (EDRs)", which will record about 20 seconds of vehicle operational data up to a crash. Two New York City teenagers who got into a street race, one driving a Corvette and the other a Mercedes, ended up plowing into a Jeep, killing a woman and her fiance. One of the teens told detectives that the cars hadn't been going faster than 55 MPH, but the Corvette's EDR said that it had been going 139 MPH when the race came to its disastrous end. The two teens ended up in prison for three years on manslaughter charges.
There is an ongoing debate over EDRs, with advocates claiming they improve automotive safety and the critics claiming they are unacceptably intrusive. The US government likes them and in fact is passing regulations to standardize them so they can all be read, by a laptop computer or whatever, using the same interface and software. Some advocates are pushing for laws to make EDRs mandatory for every car.
The critics have been vocal enough to push the US National Traffic Safety Administration to call for regulations specifying that dealers must disclose if a car has an EDR. Several US states already have this as a law, and also mandate that EDR contents cannot be downloaded without the owner's permission. Some state legislators have pushed for a law that would modify EDR systems so the owners could turn them off.
There is a concern that EDRs could be used to spy on people's driving habits. A standard EDR doesn't have the memory capacity to be much of a spy, but transport companies often fit their trucks with full-fledged black boxes to monitor driving habits over the longer term. Corporate fleet car operations also sometimes have comparable black boxes, and they are even available for, say, parents who want to make sure their teenagers aren't racing around behind their backs, with the box capable of issuing warnings when the driver speeds. The critics worry that expanded EDRs with wireless links might allow the police to bust drivers for infractions nobody witnessed, or let insurance companies adjust their rates depending on driving habits. In fact, some insurers are starting to push ideas along this line.
EDR data is currently admissible as evidence in 19 US states, and has led to a number of convictions. The political quarrel over EDRs continues. For now, everyone agrees that drivers should realize that their car may be keeping tabs on them.
* IRAN RUNNING DRY: The current regime in Teheran has been a persistent annoyance to the West, but as discussed in an article in BUSINESS WEEK ("Surprise: Oil Woes In Iran" by Stanley Reed, 11 December 2006), opponents of Iran can take some comfort in the fact that the country is now finding it harder and harder to pump oil.
At 137 billion barrels of oil, Iran has the second biggest deposits in the world, after Saudi Arabia. However, the rate at which the Iranians have been pumping that oil has been steadily declining. In 1974, five years before the Islamic Revolution, Iran was pumping 6.1 million barrels a day; now it's only pumping 3.9 million. About 60% of Iran's fields are more than 50 years old and are starting to run dry. Officials of the National Iranian Oil Company (NIOC) know there's a problem and have been warning the government that unless things change, Iran's oil flow will continue to dwindle.
Underinvestment is the key to the problem. Iran funds NIOC at about $3 billion USD a year, which is about a third of what's needed. Gasoline prices are set at only 35 cents a gallon, guaranteeing high consumption -- in fact, so high that national gasoline use has outstripped Iranian refinery capabilities. Iran imported about 40% of its gasoline in 2006 at a cost of $5 billion USD. The subsidy on gasoline is part of the general problem that the current Iranian government under President Mahmoud Ahmadinejad has been bracing up public support by lavish public spending. To an extent that generosity has been boosted by high oil prices, but oil prices have been falling and the Teheran government could find itself in a nasty pinch.
The government also seems to have mixed feelings about obtaining foreign help to pump oil. To be sure, the Iranians have good cause to be suspicious of foreigners involved in their oil industry, having been handed some raw deals in pre-revolutionary days, but the truth of the matter is that Iran needs the help. Xenophobia and revolutionary bureaucracy have choked off deals, as have international sanctions -- which are likely to get tougher as long as Iran continues to flaunt its nuclear program. Iran shares a huge offshore natural gas field with Qatar, but while the Qataris have been signing huge deals to tap into the field, Iranian efforts have been moving along at a crawl at best.
Those tempted to gloat about Iran's fumblings in the oil business should probably not take their glee too far, however. The Iranians were able to substantially boost oil production during the Iran-Iraq War of the 1980s without any foreign assistance, and the Iranians have shown they can be enterprising, for example having developed a local arms industry capable of building sophisticated weaponry. There's no law of physics to prevent Iran from turning around its oil industry -- though the critics of the current government can find some hope in the thought that such a turnaround may imply at least a regime less focused on grandstanding and causing trouble, and more focused on taking care of business.
* As another case in point, a BBC WORLD TV report indicated that Iran is suffering the worst "brain drain" of any major country on the planet. Young educated Iranians are leaving the country in mass to seek a better life elsewhere. Their motivations are not particularly ideological: it's just that unemployment is high in Iran and there's no work for them, an unpleasant circumstance adding to the impression that the current government is theatrical but incompetent.
Recent elections showed reformists regaining some of the ground they had lost to the conservatives, but again, those who might gloat should find it useful to remember that past hopes for a kinder, gentler Islamic Republic of Iran have consistently led to disappointment -- and given that current US attitudes towards Iran are, with some good reason, not exactly kind and gentle themselves, doesn't give an excessive basis for optimism.
* A SHORT HISTORY OF LIFE (5): After about three billion years of what might be called modest and incremental progress, with the beginning of the Cambrian period, 570 million years ago, life shifted gears into HIGH with a vengeance.
The most distinctive citizens of the Cambrian were the "trilobites", which were early representatives of the "arthropods" -- the phylum which in modern days is represented by crustaceans (crabs and lobsters), arachnids (spiders and scorpions), and insects. The arthropods have external "exoskeletons" and can only grow by shedding them every now and then. The trilobites are often compared to modern woodlice (AKA pill bugs) or horseshoe crabs, but they represented a family of their own, one which would not survive to the present. (Incidentally, horseshoe crabs are not really crabs, being more closely related to spiders.)
There were also "brachiopods", which most people would call "clams" on sight, but they're a phylum of their own, no more closely related to clams than trilobites are. In particular, their shell halves are clearly different. Brachiopods survive today, mostly as small forms in arctic waters. Small molluscs -- what we know today as the true clams, snails, and so on -- also made their appearance.
The trilobites and brachiopods are noticeable in the Cambrian fossil record because they had hard body parts. However, soft-bodied animals also left their traces in Cambrian stone, most significantly in the "Burgess shale" deposits of the Canadian Rockies. The 120 or so creatures found in the Burgess shale range from various kinds of sea worms to utterly bizarre creatures -- one animal that looked like a caterpillar with spines is even called Hallucigenia, the paleontologist who found it being perfectly amazed at the thing.
The soft-bodied creatures also included animals ancestral to fish, represented by the "living fossil" -- with the usual qualifications attached to that term -- know as a "lancelet" or "amphioxus". A modern lancelet actually looks a bit like a minnow, with a streamlined shape and a swimming tailfin, but though it has a spinal nerve cord, it has nothing that faintly resembles bones and has the most rudimentary excuses for eyes and a brain. However, the ancestral lancelets of the Cambrian were clearly a pattern that could be elaborated on in time.
At the time, the map of the Earth didn't look anything like it did today. It was discovered in the 20th century that continents drift slowly over the surface of the Earth, a finding that explained a lot of mysterious geology, and during the Cambrian the continents were arranged differently. One continent, Rodinia, was splitting up at the time, breaking off fragments, while two others, Gondwana and Laurasia, were in the process of colliding, forming a "supercontinent" named Pangea, partly enclosing the equatorial Tethys Sea. The land was empty, but the seas were widespread and provided plenty of space for life to flourish.
* Exactly why was there such a burst of enthusiasm at the beginning of the Cambrian? The matter is hotly debated. It is known that the Earth's atmosphere finally acquired oxygen concentrations similar to those of modern times, after aeons in which oxygen was in relatively short supply. The availability of oxygen permitted more aggressive growth of life in general. Some have speculated that the "invention" of shells and of effective eyes led to an "arms race" that pushed natural selection into high gear.
One point of view is that the changes weren't so abrupt as has been made out. The Cambrian saw the emergence of shelled animals, which left better fossils than their soft-bodies predecessors, and so get higher billing in the fossil record. Even shelled animals might not have been such an abrupt innovation, possibly having been preceded by very small Precambrian shelled animals that have generally escaped attention. In addition, although some paleontologists have claimed the Cambrian was marked by large numbers of entirely unique phyla -- Stephen Jay Gould pushed this idea in his book WONDERFUL LIFE -- critics accuse them of exaggerating, pointing out that supposedly unique life-forms of the era can actually be generally accommodated in known phyla.
The squabbling over the matter hardly seems surprising. Once again, taxonomy is inherently troublesome, and all the more troublesome for life-forms hundreds of millions of years old, found only as shadows in the stone. Despite all the quarreling and debate, paleontologists are united in one opinion on the matter, emphatically rejecting assertions by critics of Darwin that the Cambrian explosion can't be accounted for by evolutionary theory. In fact, Darwin's advocates find it more of an exciting playground than a dire threat. [TO BE CONTINUED]
* INFRASTRUCTURE -- THE POWER GRID (1): Chapter 6 of Brian Hayes' book INFRASTRUCTURE focuses on the power grid that delivers electricity from power plants to end users.
It's useful here to first explain some very elementary electrical theory. There are four forces in the Universe: two of them, the strong and weak nuclear forces, only operate at the subatomic level and we don't notice them directly at our level. We do, however, notice the other two, gravity and electromagnetism.
We generally have an intuitive grasp of gravity, and it's useful to give it a quick outline here since it its operation is similar to that of electromagnetism in many ways. Gravity is an attractive force between two masses, proportional to the product of the two masses and inversely proportional to the square of the distance between them. Down here on the surface of the Earth, we see gravity in a simpler fashion, being a force exerted on any mass we try to lift that would accelerate it at 9.81 meters per second squared if the mass were released, and which is constant with height -- or at least it seems to be from our ant's point of view, a rucksack weighing for all practical purposes the same at the bottom of a mountain as it does at the top. (The Earth's gravitational force is effectively exerted as if all the mass of the planet were at its center, and the distance climbing up the mountain is so much smaller than the radius of the Earth as to make the change unnoticeable, though it's not unmeasurable.)
The most useful example of gravity in this context is water falling down a pipe. The taller the pipe, the greater the energy acquired by the water per unit mass as it falls down: double the height, double the energy. The height of the pipe can be said to correspond to the gravitational "potential" of the flow, with the potential increasing with the height of the pipe. Of course, the total energy, not just the energy per unit mass, is proportional to the cross-section of the pipe and the amount of water that flows down the pipe: double the cross section, double the energy. Double both the height and the cross section, get four times the energy.
This is the physical basis of a hydropower station, with the amount of power obtained from a turbine proportional to the height or head of water flowing into it and the flow rate of that water. Incidentally, power is the rate of energy, or energy per second. If a hydropower station was to empty a reservoir with a given amount of water in it, the result would be the same amount of energy no matter how quickly it was done, but the power would depend on the rate at which the water was drained. Double the flow rate, double the power -- but the reservoir is emptied twice as fast and the total energy remains the same.
Electromagnetism is similar to gravity in that it is a force between two objects with a quantity of what is called "electric charge", with the force proportional to the product of the charges of the two objects and inversely proportional to the square of the distance between them. It differs from gravity in that there are two types of charge, "positive" and "negative", and the force can operate in two directions, not just one: like charges repel, unlike charges attract.
So what exactly is a "charge"? It is difficult to define since it's a fundamental concept. What's a charge? It's what creates the electromagnetic force. What's the electromagnetic force? It's what's created by charges. In practice, we can think of a charge as consisting of a collection of subatomic particles called "electrons", each of which has a single fundamental unit of (negative) electric charge. The more electrons, the greater the charge. There's more than a little fine print to this description -- one distinction being that electrons aren't charges, they are particles that have charge -- but such issues will be ignored here for the sake of simplicity, and we can think of an electric charge as just being an accumulation of electrons.
To get a more practical notion of electricity, consider the simplest possible electric circuit, consisting of a battery with a resistor "load" wired across its terminals. The battery is a source of electricity, provided at a given "voltage" or "electro-motive force (EMF)". Voltage is given in "volts" and formally defined as the "energy per unit charge", but more intuitively it can be seen as analogous to the "height" of a flow of water falling under a gravity, and in fact voltage is also called "electrical potential". The electrons pouring out of the battery form a "current" given in "amperes", flowing by convention from the "+" to the "-" terminals of the battery -- though this convention exists for historical reasons, the electrons actually flowing from "-" to "+".
Anyway, just like with a hydropower station, in which the power of the flow
is given by the height times the current flow, in our little electric circuit
the electric power is the voltage times the current flow:
power in watts = voltage * current = volts * amperes
That is, given a 3 volt battery driving 2 amperes, the output power is 6
watts.
Batteries operate at a more or less fixed voltage output. What determines
the current for that voltage is the size of the resistive load. It's just
like having a pipe of one diameter or another at our hydropower station, able
to support more or less current flow depending on that diameter. In fact,
one definition of resistance is that it gives the ratio of current to
voltage:
resistance in ohms = voltage / current
That is, given a 3 volt battery and 2 amperes of current, the resistance
value is 1.5 ohms. (This is a very small value of resistance.) This
equation can of course be rearranged into two other useful forms:
voltage = current * resistance
current = voltage / resistance
That is, push a current of a half an ampere through a 100 ohm resistor, the
voltage across the resistor is 50 volts. Similarly, if 3 volts is placed
across a 100 ohm resistor, then the current is 30 milliamperes.
Actually, although the definition of resistance as the ratio of voltage to
current is true, as described later it's a bit oversimplified, and there's an
important and not-to-be-forgotten distinction in the definition of
resistance, in that the energy pumped into the resistor is entirely consumed
by it -- that is, a resistance is a circuit load that converts electrical
energy into other forms. (This is not true for all circuit loads.) For
example, the heating elements of a toaster or electric stove are essentially
just resistors that convert electrical energy into heat. A traditional
electric light bulb is a resistor that converts electric energy into heat and
light. Since:
power = voltage * current
voltage = current * resistance
current = voltage / resistance
-- then by a little algebra, the electric power burned up in a resistor is
given by:
power = current^2 * resistance
power = voltage^2 / resistance
That is, drive half an ampere through a 100 ohm resistance, the power output
is 25 watts. Put 3 volts across a 100 ohm resistance, the power output is 90
milliwatts.
It might be nice here to point out the definitions of an "open circuit" and a "short circuit". As implied above, electricity has to flow in a complete loop or circuit; put a switch in the circuit described above and open it, then no current flows through the circuit -- "open circuit". However, attempting to wire across the load in this circuit -- "short circuit" it -- and the resistance drops to a very low level. If the voltage is constant, then the result is a large current and usually a bit of fireworks.
The current that flows in a short circuit is limited by the amount of current the source can produce. A small battery cannot produce much current, so usually shorting one out doesn't create much ruckus, though it at the very least drains the battery. Electrical engineers like to think of a source as having an "internal resistance", sort of like a resistor magically integrated into the battery, with the resistance value given by the open-circuit voltage divided by the short-circuit current.
A source that can produce a lot of current has a low internal resistance -- a good example being an automotive battery. People will often say they got a shock off of a car battery, but one could put a thumb on each terminal of a car battery and not feel a thing, the voltage is too low to drive a perceptible current through the body's resistance. However, one terminal of the battery is connected to the car chassis while the other is connected to automotive systems like the starter, and if a mechanic clumsily places a wrench from a "hot" element to the chassis "ground", the result is a short circuit and sparks. An automotive battery can source a lot of current, it has a low internal resistance, and that is why it's not a good idea to wear a watch with a metal band when working under the hood of a car.
Incidentally, high voltages are not necessarily dangerous in themselves. The static shock one gets after scuffing one's shoes on a pile carpet actually has a surprisingly high voltage -- it has to be to throw off a spark, which is due to the ionization of molecules in the air -- but the total charge is low and the spark carries little power. [TO BE CONTINUED]
* CANADA ROUNDABOUT: As discussed in THE ECONOMIST ("Joining The Rotary Club", 11 November 2006), over the past few years, Canadian drivers have become accustomed to the roundabout, where instead negotiating a four-way stop the drivers turn right into a loop and then turn right again to go on their way. The notion of a roundabout wasn't entirely new to the country, the idea having been implemented many decades ago, but the old roundabouts were much bigger and had a peculiar feature: the vehicles entering the loop had right-of-way over vehicles in the loop. From a modern perspective, this was obviously the wrong approach, making the roundabout into a traffic obstruction instead of a benefit.
The bad taste lingered for a long time. The modern roundabout was invented in the UK in the 1960s and caught on in Europe, but Canada and the US -- which had gone through much the same experience as the Canadians -- were leery. However, the Americans started adopting roundabouts in the early 1990s, and the Canadians finally began to take notice. Canadian traffic engineers did a detailed study of the US experience and concluded that roundabouts eased traffic flow, were safer than four-way stops, improved gas mileage, and reduced emissions. They also worked even when the traffic lights were down.
Now there are traffic roundabouts all across Canada. Canadian drivers haven't had much trouble with them, though one driver who turned left instead of right ended up going in reverse around the loop. There have been problems in big cities like Montreal with drivers refusing to let pedestrians get across, but now drivers are being heavily fined if they don't yield to foot traffic. There were concerns about snow, but snowplows seem to be able to keep the roundabouts working by simply going round until the snow is all cleared away.
* ED: Traffic roundabouts are still not the norm in the US, mostly being found in new shopping malls and housing developments. Retrofitting them to existing street systems is expensive and so it's taking time to put them in place. A roundabout was installed at a somewhat tangled street intersection a stone's throw from my house to straighten out the traffic flow, and it seems to work well.
I really like roundabouts. Not only do they eliminate the petty confrontations, frustration, and occasional stupid screwups of a four-way stop, but they gives a slight fun feeling from way back of being on one of those theme-park kiddie-car rides that go in circles and circles -- not that I've ever been inclined to keep going around and around in the loop, though on rare occasions a traffic conflict can force me to do another 360. There's also a tendency to landscape the roundabout center nicely or even put statuary and fountains in it, the most spectacular example being the roundabout in Idaho Falls I mentioned in the travelogue for my last road trip.
* SPAM HUNTERS: Last spring, the BBC conducted an investigation of a particular series of spam email messages trying to sell pharmaceuticals. According to the report on the exercise ("Spam Trail Uncovers Junk Empire" by Mark Ward) the investigators uncovered some interesting details
The spam under scrutiny was originally sent out during April and May 2006. The emails were typical of spam hawking pharmaceuticals, except for the fact that the volume was unusually heavy, with about 100 million emails sent out every 14 days. Many of the emails had citations from JRR Tolkien's classic fantasy novel THE HOBBIT, with the text included to try to convince spam filters that the emails were legitimate. This is a common trick among spammers; what was more interesting was that there were about 2,000 variations in the content of the messages, with the content changed a few times an hour during the distribution to prevent spam filters from getting wise.
Tracking the origin of the emails uncovered a "zombienet" of about 100,000 compromised PCs in 119 different nations, with most of the PCs centered in Europe. Since spam filters will target particular PCs that are sources of spam, the zombienet tended to acquire new PCs on a regular basis and discard old ones. To allow customers to buy the drugs, the spam network included 1,500 different web domains, with some of the domains run by ISPs who advertise themselves as "bullet proof" -- meaning they resist attempts to shut down their hosted websites, making them friendly to cybercrooks. The links vectored potential customers to websites that looked like slick, legitimate businesses, even with street addresses and other physical data, though they were inevitably "virtual" -- complete fabrications.
The investigators used a one-shot credit card to make a purchase, and actually got the product they ordered, though the expectation was that the exercise was a credit-card ripoff operation. The orders were fulfilled by a pharmaceutical firm in India; the drugs were sent for testing to see if they were what was advertized, though the results hadn't come back by the time the story went to press. The investigators have been trying to hunt through the cybermaze further, and have passed on data to the US FBI on a US-based hosting firm noted to have been associated with spam and cybercrime efforts in the past.
* A later BEEB Online article claims that cybercrime gangs are taking a longer view of their activities, with students enrolled in university computer science programs being given "scholarship" by the gangs to help them obtain degrees -- and giving them a guaranteed job after graduation. The gangs also surf forums and chat rooms to find young "helpers", sometimes no older than 14, to run errands while being groomed for greater efforts later. The gangs also attempt to recruit corporate personnel to help line up very profitable "inside jobs".
A report in CNET Online News says the London Metropolitan Police have stated that local police forces in the UK are now being swamped with complaints about cybercrimes, while very few hackers and virus-writers end up in the dock. The recommendation was to establish a national cybercrime unit to take up the load.
* ED: On my personal cybercrime front, I recently got an email to ask me to check my Paypal account. It was an obvious scam, one giveaway being it didn't refer to me by name, another being that it came into an email account that Paypal knows nothing about. What was amusing was that when I brought up the email in Outlook, the banner described the character set as "Cyrillic" -- hmm, missed a trick there, Russky boy.
The email did have a good trick in providing what would seem to be a completely valid hyperlink to "http://www.paypal.com". My initial reaction was: "Huh?" How could they pull off a scam referring me to the legitimate PayPal website? The answer immediately popped into my head: It was a label for a link, not the link itself, hiding the scam link underneath.
* GREEN CHINA: An article in THE ECONOMIST ("Visions Of Ecopolis", 23 September 2006) provided a detailed tour of one of China's latest efforts to bring the country up to the leading edge of the modern world: a new city designed from the ground up with the environment in mind.
The new city, Dongtan, is being built on Chongming, an island of silt in the estuary of the Yangzi River, with Shanghai, at 9.5 million people China's biggest city, on the south bank of the river. The plan is to open Dongtan to the first residents in 2010; the city will be self-sufficient in energy and water, and will use fuel-cell powered buses as well as other "green" transport systems.
Right now Chongming, which is about 80 kilometers long and 17 kilometers wide (50 by 11 miles) has a population of about 650,000, mostly farmers. Some of the farmland will be turned into forest, the rest being adapted to organic farming methods. Wetlands will be converted into parks, with wide buffers to prevent development from encroaching on them. Dongtan will be at the downstream end of the island; only about a fifth of the island will be urbanized. The island will operate as a pleasant resort for Shanghai residents.
Shanghai has been growing rapidly, with glittering skyscrapers often built by foreign firms. Government authorities have been becoming increasingly uneasy with the breakneck growth, and are enthusiastic about Dongtan as a way of assessing alternatives. Foreigners are helping with Dongtan, too, with Arup, a British construction firm, assisting in the program.
The Arup plan sees Dongtan growing in three phases, with phase 1 to be complete by 2010 and providing living space for 25,000 people. By 2040, the city will accommodate a half-million souls. It will be an ecotopian paradise, combining classic Chinese design with the latest technology. Energy will be provided by wind turbines and biofuels made from agricultural waste. Most of the city's trash will be recycled, and sewage will be processed to be fed back into the farm system. All farming will be organic, and "green building" technologies will cut the amount of energy used to heat and cool buildings by 70%.
Dongtan will be compact, making it easy to get around. Public transport will include solar-powered water taxis cruising the city's canals, and fuel-cell-powered buses. No internal combustion ground vehicles will be normally allowed in the city.
This sounds like a environmentalist's notion of a Disney theme park, and that's what it could end up being. Shanghai plans to host the World Expo in 2010 and wants Dongtan open by then to draw in tourists. The authorities still insist that they are serious, and point out that if Dongtan may not be an actual vision for a world that could exist in practice, it will provide an experimental laboratory for ideas that could catch on elsewhere. Even critics have to admit: it's worth a shot.
* A SHORT HISTORY OF LIFE (4): The rise of single-celled eukaryotic cells in the Precambrian led, it seems quickly, to the development of multicellular life-forms. In some ways, it seems like an obvious evolutionary gambit. One life-form that could be seen as a sort of "living fossil" is the "volvox", a colony of protist algae that takes on a neat spherical form. Obviously, it was not such a big step to develop more sophisticated organizations.
Or was it? Beyond the volvox and other colonies of protists, a multicellular organism is much more devious than a big mass of cells. It has to know the trick of starting out with a single cell whose genetic "program" knows how direct the organization of all successor cells, with cells taking on different forms, in effect running their own modified versions of the "program" as the organism takes shape, with all the cells cooperatively shaping the whole: a place for everything, and everything in its place. Even multicellular protists never figured out how to generate different types of cells. This is a difficult stunt and we're still learning a great deal about how it works, but it appears that life-forms were beginning to acquire the trick as far back as 1.2 billion years ago.
By the late Precambrian, the multicellular bandwagon had got rolling well enough to have produced early members of the three most familiar kingdoms of life: the plants, which could photosynthesize; the fungi, which digest their food from the external environment; and the animals, which ingest their food for digestion. Incidentally, there's a tendency to consider fungi like mushrooms to be plants, but they're really no more plants than we are. Certainly anybody who's ever had a fungal infection on their toes might wonder what kind of plant it is that eats away living flesh.
In any case, multicellular life forms were thriving by the late Precambrian. The overall kingdom of animals is the "metazoa", with three different groups of phyla or "superphyla":
The most famous late-Precambrian fossil bed is in the Ediacara Hills of South Australia, with the creatures found there sometimes referred to as "Ediacaran" life-forms. Their classification is controversial, to no surprise. Taxonomists have enough trouble trying to organize life-forms that they can get their hands on, and it's far more troublesome to figure it out when all that they have is a shadow in stone. An insubstantial creature like a jellyfish doesn't even leave much of a shadow, so it's very difficult to figure out how to pigeonhole the creatures of the Precambrian. Is a particular organism a precursor of some modern form, or does it represent an early experiment that went to a dead end?
It's difficult to know one way or another, but it does seem that by the late Precambrian what we would call "simple" multicellular organisms were well established -- animals, simple plants, and fungi. The world seems to have been a harsh place late in the Precambrian -- heavily covered with glaciers, with some suggesting that maybe the entire planet froze over -- but it didn't slow down the elaboration of life-forms on Earth. In fact, it would soon undergo a spectacular explosion. [TO BE CONTINUED]
* INFRASTRUCTURE -- POWER PLANTS (7): Much fuss about renewable energy is being made in these days of expensive energy. To an extent, we've been making extensive use of renewable energy, in the form of hydropower from dams, for over a century. In fact, in the 1930s, hydropower provided about 40% of the electricity for the USA, but now the proportion is only about 15% -- electricity demand has grown and the number of sites where hydropower is cost-effective is limited, meaning that most of the good sites are already in use.
The power from a water flow is a product of the head, the height the water has to fall, and the total volume of water flow. Given a high head but low volume, the best conversion scheme is the "Pelton wheel". The Pelton wheel -- insiders call it a "runner", not a "wheel" -- spins in air on a horizontal shaft; water is forced through nozzles against buckets on the rim to spin it around at a high rate, driving a generator system. The Pelton wheel is regarded as a form of "impulse turbine".
For low head and large volume a "reaction-wheel turbine" works better. It spins on a vertical shaft immersed in the water flow inside a snail-shaped chamber. While the Pelton wheel can run at the 3,600 RPM needed for 60 Hz power, the reaction-wheel turbine runs much more slowly, at 60 RPM; to generate 60 Hz power, then the reaction-wheel generator must have 60 sets of windings. Not surprisingly, the generators are in the form of wide flattened drums, rotating around the vertical axis above their turbines.
In some dams, the powerhouse is built at the base of the dam, but in other cases it's in a separate powerhouse, fed by wide penstock pipes, and possibly kilometers away. In that case, there will be a "surge tank" somewhere along the penstock run, kept about half-full to provide more water if the gates to the turbines are opened, or soaking up "water hammer" if they are closed. It is much easier to adjust the power output of a hydropower plant than an steam power plant, and so hydropower is convenient for handling peak loads.
* Wind power has also been around for a long time, in the form of wind-driven pumps and mills. The traditional Dutch windmill is something of a stereotype around the world, but those of us who live in the Western USA and Canada are familiar with the common Aeromotor-type farm windmills, which are still spinning away on the prairies, pumping water indefinitely.
Now Westerners are generally familiar with the modern "wind turbines" that increasingly dot the plains and ridgelines, with their three-bladed rotors spinning around in a hypnotic fashion. They have the same relationship to an Aeromotor windmill that a jetliner has to a covered wagon, both in sophistication and scale. Wind turbines have a control system to keep the rotors pointed into the wind; it might seem easier to have them point away from the wind, but the wind passing around the pylon sets up a "wind shadow" that will unbalance the rotation of the turbine.
The rotor blades generally have variable "pitch" to ensure that the rotor spins at a constant RPM; in really powerful winds that could tear the turbine apart, the blades are "feathered" to prevent them from catching the wind. Some designs used deployable "spoiler" surfaces on the blades to ruin their aerodynamics and slow them down instead. There is an emergency brake if all else fails. Wind power is on a roll in the US and Europe, but even its most enthusiastic backers admit that it will never provide more than 10% or so of power needs. Wind power also tends to be somewhat inconstant, though turbines are of course set up in places that tend to be consistently breezy. Still, with high energy prices wind power looks like a very good deal.
* The sexiest, and so far most disappointing, renewable energy source is solar power. Solar power has a major limitation, in that it only works during the day, meaning that on the average it's operational for only half the time. It also doesn't work well in bad weather.
Solar water heating has been around for a long time, involving water-filled pipes looped through glass-topped, black-painted boxes set up on rooftops. Experience with such schemes has been mixed, since the heating can be uneven and the maintenance troublesome.
Solar electric-power systems are a more modern invention. There are two main approaches: solar thermal and photovoltaic (PV). Solar thermal involves focusing sunlight with mirrors on pipes filled with oil or the like, the heat obtained then being dumped by heat exchangers into a steam-driven power turbine system. So far, solar thermal has been limited to demonstrator plants, and there is some skepticism that it's the right way to go.
There's a lot more enthusiasm about PV, which involves solid-state devices mounted on a rooftop panel to convert sunlight directly into DC electricity. The technology was originally used in the 1960s for spacecraft, but now it's in widespread use, as cost has come down and efficiencies have gone up. However, there's a tradeoff between cost and efficiency, or in other words cheap PV panels aren't all that efficient and efficient PV panels aren't all that cheap, and despite improvements PV is still an expensive form of power.
Still, it's nothing unusual to see remote stations for communications or traffic control and the like with PV panels for power, and in third-world countries cheap PV panels are popular, allowing citizens with little or no access to a reliable power grid to charge up a battery to run a TV or radio or cellphone charger. Solar keeps on getting cheaper and more efficient and obviously has a bright future, though given its vulnerability to nightfall, it seems hard to figure out how it could handle all electricity needs. Some have imagined building huge solar-power satellites in high orbit that stay in the sunlight 24:7:365, beaming their power down to the Earth on microwave beams, but though all the elements of such a scheme are technically feasible, that's obviously an option for a later generation when the costs of spaceflight are much cheaper than they are now.
* Geothermal power is another alternative energy source that's been around a long time, with steam from hot underground wells used to drive a generator system. It has an obvious limitation: it requires locations that have geothermal activity, meaning it works very well in Iceland and in various locales dotted around other countries, but it's almost irrelevant to the rest of the planet.
If the steam is hot enough, it can be used to drive a turbine directly, though the output has to be cooled and pumped back underground again: not surprisingly it's sulfurous, meaning it wouldn't do just to vent it, and the underground reservoir would be depleted quickly if it weren't. A geothermal plant that operates on such "dry steam" will inevitably have a cooling tower system.
It is possible to generate power using cooler sources, which produce hot water and steam instead of just steam, but it requires a more complicated approach, for example using the hot water and steam to drive a secondary loop filled with ammonia to drive a turbine. That increases expense. In any case, a geothermal plant will have a lot of thick piping, much of it wrapped in thick insulation to keep the heat from leaking away uselessly, and featuring inchworm-like expansion loops to allow the pipes to expand or contract. [END OF SET 5]
* YOU HAVE BEEN WARNED: According to a BBC WORLD Online article, ("Wacky
Warnings Rewarded in the US"), the "Michigan Lawsuit Abuse Watch (M-LAW)", an
interest group focused on reform of civil lawsuits, has released its tenth
annual listing of the "wackiest warnings" on products. The winner was on a
washing machine:
DO NOT put any person in this washer.
The second prize was a label on an engine that read: "Never use a lit match
or open flame to check fuel level." Third prize was a tie, with a warning
not to try to dry mobile phones in microwave ovens matched by a warning not
to iron lottery tickets. Honorable mention went to a phonebook that warned:
"Please do not use this directory while operating a moving vehicle".
The warnings were compiled by M-LAW and put to a popular vote by a Detroit radio station. A spokesman for the manufacturer of the washing machine replied that the company had been sued by parents whose toddlers had climbed into washing machines. No doubt that was actually the point of the M-LAW exercise, demonstrating how absurd the law was to even consider lawsuits over such things. After all, any adult mad enough to put a toddler in a washing machine won't heed warning labels, and as far as toddlers go -- they can't read.
* ANOTHER MONTH: I had a little pocket money left over last month and decided to buy a cheap MP3-CD stereo system. It was an RCA unit, with a cost of about a hundred bucks, with a five-disc carousel and AM/FM radio. I thought it was maybe more than I needed, but once I had it set up I appreciated it. There's the old phenomenon of "buyer remorse", that is the sense of regret in buying something that doesn't measure up to expectations, but there's also "buyer gratification", the sense of pleasure that comes in buying something that turns out better than anticipated. Though I'm no longer at the age of wanting to shake the windows of my house, I liked the relatively high power of the 300 watt sound system, and once I saw that the five-disk changer gave me over three gigabytes of music, I realized that I couldn't have purchased a music pod with that capacity for that money.
I got to thinking about the advance of consumer technology and realized that the box would have been a marvel of technology and capability in 1970, and in 1970 dollars would have cost less than fifty bucks. I also got to thinking about the fact that, on taking the product out of the carton and setting it up, all I had was a plastic box with cryptic lights and buttons -- but a day later I was operating it using its ordinary features with perfect comfort.
Now it hardly takes a brainiac to dope out a cheap stereo system, but the exercise did show how much context the ordinary modern consumer has upstairs for use of what amounts to high technology. One of my favorite sci-fi novels when I was a kid was Poul Anderson's THE HIGH CRUSADE, which envisioned a group of medieval knights and their people being picked up by a scout ship from an alien invasion force -- to then turn the tables on the invaders and set up a galactic empire.
It was a fun book, the premise being that our ancestors didn't have our level of knowledge but weren't stupid, with medieval nobility having a particularly refined understanding of the art of intrigue. However, the book said something that I swallowed at the time but all later experience would prove was five-star stupid: that medieval peasants would quickly adapt to the use of advanced technology. They were used to dealing with complicated mechanical devices, and in contrast pushing buttons would be trivial.
The thing about a mechanical device is that all its workings are more or less visible, which is not the case for an electronic box. One wonders how long a medieval peasant would have to puzzle with my cheap RCA stereo system before he could figure it out. The first thing he'd have to understand was what the damn thing actually did -- and then operating it would be another challenge. He might well get it working eventually, but it would take a lot longer than a day -- and something like a personal computer would be a challenge ten, a hundred times bigger. Anybody who's a technophile occasionally runs into unfortunate people who simply have no affinity with technology; confronted with a complicated gadget, they freeze up like a deer trapped in a spotlight. A medieval peasant would be even worse off -- after all, almost none of them could even read.
Most modern consumers have a certain model upstairs about how technology works and how to operate it, and so getting on board a new product is generally straightforward. It is easy to take it for granted that this model is the product of a lifetime of experience, and forget that someone from a different environment, no matter how intelligent, doesn't have that context.