When the towers fell


The World Trade Center towers (photo: Carol M. Highsmith)

I continue to see bizarre and ill-informed conspiracy theories on the Internet about the 2001 collapse of the World Trade Center towers (above). This is in spite of the detailed investigations of, and voluminous reports on, the event.


Steel softens at temperatures well below the melting point of 1400°C

In fact, it has long been known that structural steel buildings like the World Trade Center can collapse due to fire. In 1967, the structural steel roof of McCormick Place in Chicago collapsed because of softening due to a fire. This collapse began only about 30–45 minutes after the fire was reported.


The World Trade Center under construction (photo: Eric Shaw White)

In the case of the World Trade Center, this fundamental problem with structural steel was combined with building-specific design flaws. Still, in my view, concrete construction is simply safer. Concrete resists fire far better than steel, and locating fire escapes inside a thick concrete core assists evacuation, should that be needed. The 9/11 conspiracy theories are just silly, though.


A concrete tower under construction in Australia (photo: Erin Silversmith,)


Disasters in science #3

Engineers have a moral obligation to take great care with safety-related issues. As Kipling says, “They do not preach that their God will rouse them a little before the nuts work loose. They do not teach that His Pity allows them to leave their job when they damn-well choose.


Disasters in science #2

This “meme” is intended to underscore the fact that engineers have a moral obligation to take great care with safety-related issues. As Kipling says, “It is their care that the gear engages; it is their care that the switches lock.


The magnificent Doble steam car

The video above shows the beautiful 1920s Doble steam car owned by Jay Leno (see this article). This magnificent vehicle represents the pinnacle of a technology that was already dead when it was built. A front-mounted boiler powers four cylinders at the rear, which drive the back wheels via spur gears (see below). There is no traditional gearbox or transmission. The steam is condensed and recycled, so that water does not have to be constantly replenished. All very efficient.

Leno says that “The last days of an old technology are almost always better than the first days of a new technology,” and aesthetically (in spite of my love of solar cars) he is probably right. Something similar can be said about the ultimate examples of castle-building, which occurred when castles were already obsolete (see below). So watch the video of this wonderful vintage car!


How many parts?

The diagram below shows the complexity, in terms of numbers of parts, of some human constructions. Interestingly, there is an approximate complexity plateau which starts at or before the Great Pyramid of Giza (constructed between about 2580 BC and 2560 BC, and composed of around 2.3 million stone blocks). The plateau continues through the dome of Florence Cathedral (brilliantly designed by Filippo Brunelleschi, made up of over 4 million bricks, and completed in 1436). A late member of the plateau is the Boeing 747 (first flown in 1969, and composed of around 6 million parts). The Great Pyramid required the resources of a nation, Brunelleschi’s dome those of a city-state, and the 747 those of a large company.

Somewhat less complex are the Antikythera mechanism and John Harrison’s H1 chronometer (a five-year effort by one man). The PDP-8/S (1966) and the original Apple Macintosh (1984) were widely popular low-cost computers. For those, I’ve interpreted “parts” as either transistors, individual bits of ferrite core memory, or bytes of semiconductor memory.

The recent iPhone 6s stands out from the simpler computers: the A9 processor has over 3 billion transistors, and the phone comes with at least 18 GB of memory. The iPhone 6s puts the power of a mid-80s Cray-2 supercomputer in a handheld device. Producing one requires the resources of an international network of specialised companies, with the processor and memory being fabricated in South Korea or Taiwan, the camera and display in Japan, and the accelerometer in Germany. The software is developed in the USA, and final assembly is mostly done in China. It seem unlikely that any one nation would be able to construct a device as complex as this.

Maybe I should get one.

Infrastructure in the USA

I-35W Mississippi River bridge collapse
I-35W Mississippi River bridge collapse (2007)

The American Society of Civil Engineers has prepared a report card on the USA’s infrastructure. It’s a sobering read. They give the nation an overall rating of D+, noting that, for example, 70,000 bridges are in need of repair, and US$3.6 trillion needs to be spent by 2020. The image above, of the I-35W Mississippi River bridge which collapsed in 2007, illustrates the problem. Another bridge collapsed in Washington state in 2013.

Overall Score D+
Energy D+
Schools D
Public Parks & Recreation C−
Transit D
Roads D
Rail C+
Ports C
Inland Waterways D−
Bridges C+
Aviation D
Wastewater D
Solid Waste B−
Levees D−
Hazardous Waste D
Drinking Water D
Dams D

Scores vary from state to state. Texas gets an overall C (mediocre), for example, and Colorado a C+, while Michigan gets only a D (poor). The Flint water crisis is one of the more notable infrastructure problems in that state.

Addressing these infrastructure problems, although expensive, would certainly restore some of the jobs that the USA has lost over the last few years, and would make the USA more globally competitive. The places with the best infrastructure are Hong Kong, Singapore, the Netherlands, the United Arab Emirates, Japan, Switzerland, Germany, France, the United Kingdom, and Spain.

Damaged highway in Vermont
Damaged highway in Vermont (2008)


Moving on from the World Solar Challenge

Participating in the World Solar Challenge is a great experience for an engineering, mathematics, computer science, marketing, or media student – and a fantastic thing to put on a CV. Since 1987, close to 10,000 students have participated in the race. But what comes next?

Here is a selection of nine WSC alumni who are contributing their talents to the world in a variety of ways:

  • Ian Girard (Stanford, 2009–13, Driver/Mechanical) – now a battery pack designer for Tesla
  • Sam D’Amico (Stanford, 2011, Embedded code lead) – now a hardware engineer at Oculus VR
  • Marlies Hak (Nuon, 2013, Team Leader) – now a project leader at a transport-related IT company
  • Pujith Vijayaratnam (UNSW, 2013, Aerodynamics/Mechanical) – now doing a PhD in the biomechanics of blood flow
  • Amy Gunnell (Team Arrow, 2013–15, Driver/Mechanical) – now an automation engineer in a factory
  • Irene van den Hof (Twente, 2015, Team Leader) – now an intern at a Defence firm
  • Elmar Peters (Twente, 2015, developed the SABINE system which won the technical innovation award) – now runs a small startup developing bluetooth speaker technology
  • Daniel Haynes (Adelaide, 2015, Team Leader) – now a project engineer for an air conditioning company
  • Mark Hupkens (Nuon, 2015, Team Leader) – still heading the team and taking the car to South Africa

The thousands of other WSC alumni are, of course, also doing interesting things. I wonder what the current team-members will move on to after the 2017 race?