Category: Geek stuff

If it involves physics, math, computer science, electronics or has general geek cachet, this is the place for it.

Energy usage and the US Department of Defence

This article on space solar power (collecting energy from sunlight using one or more satellites in geostationary orbit, then beaming it down to Earth using microwaves) contains some interesting information on American military logistics in Iraq:

The armed forces are America’s single greatest consumer of oil. The Department of Defence delivers 1.6m gallons (7.3m litres) of fuel a day—accounting for 70% by weight of all supplies delivered—to its forces in Iraq alone, at a delivered cost per gallon of $5-20. It also spends over $1 per kWh on electric power (ten times the domestic civilian price) in battle zones, because electricity must often be provided using generators that run on fossil fuels.

This helps explain why militaries have such a keen interest in new energy generation and efficiency technologies.

The information on space solar power is also quite interesting. It actually seems to be a bit less infeasible than I thought, though the launching costs remain a very significant barrier.

Level and rate targets for greenhouse gas mitigation

When greenhouse gas mitigation commitments are made, the standard form is to ‘reduce by a certain percentage below the level in a base year by a target year.’ For example, 5% below 1990 levels by 2012. This can be easily converted into a target in absolute emissions. Say, cutting from 1,000 megatonnes (MT) in 1990 to 950 MT in 2020.

I have criticized the process of target-setting before, arguing that the ability of organization to set targets that look ambitious can obscure the absence of plans to actually achieve those reductions. In the end, it makes sense to focus our efforts on cutting emissions, rather than haggle over whether to cut by 65% or 70% by 2050.

Given that targets won’t be vanishing any time soon, I do have a proposal for improving one aspect of them. Rather than expressing targets are just an absolute level of emissions at a set date, they should be expressed as both an absolute level and a rate of reduction to be achieved by a target date. A financial equivalent would be to say: by 2010, I will have paid off 50% of my mortgage, and will be paying more off at a rate of $10,000 per year. What this avoids is the theoretical situation in which a state or other entity limps across the finish line, meeting a 2020 target with no new ideas and initiatives for reaching their 2050 target. This would be akin to a pharmaceutical company that has all its blockbuster drugs go off-patent simultaneously, at the same time as it has no promising new ones in the pipeline (not a hypothetical scenario for a significant number of drug companies right now).

Having a double rather than a single target doesn’t affect the disjoint between commitments and achievements, but it may help foster the kind of mindset required to build a low-carbon society.

Obama and manned spaceflight

Apparently, Barack Obama is thinking of curtailing NASA’s future manned spaceflight activities. Specifically, there has been talk of canceling the Ares 1 rocket and scaling back the Orion Crew Exploration Vehicle. If true, the news is welcome. There is very little evidence that ongoing manned programs – including the Space Shuttle and International Space Station – are generating useful science or providing other benefits. There is even greater doubt about the usefulness of returning to the moon.

Space exploration is an activity best undertaken by robots. They are cheaper to send up than humans and more capable. Given the very limited value provided by sending live people into space, it is something the United States should discontinue. At the very least, it is something that should be sharply scaled back while the government works to address America’s severe debts and other problems.

Ranking energy technologies, from wind turbines to corn ethanol

Mark Z. Jacobson, a professor of civil and environmental engineering at Stanford, headed up a study to quantitatively evaluate different electricity generation options, taking into consideration their impacts on climate, health, energy security, water supply, land use, wildlife, and more:

The raw energy sources that Jacobson found to be the most promising are, in order, wind, concentrated solar (the use of mirrors to heat a fluid), geothermal, tidal, solar photovoltaics (rooftop solar panels), wave and hydroelectric. He recommends against nuclear, coal with carbon capture and sequestration, corn ethanol and cellulosic ethanol, which is made of prairie grass. In fact, he found cellulosic ethanol was worse than corn ethanol because it results in more air pollution, requires more land to produce and causes more damage to wildlife.

It is naturally very difficult to assess the validity of any particular research methodology, given uncertainties about matters like the future development of technologies, the evolution of the global economy, the availability of fossil fuels, and so on. Nonetheless, it is good to see serious work being done on comparing the overall appropriateness of different energy technologies. Given the unwillingness of many states to impose serious carbon pricing solutions, and the tendency of governments to ‘pick winners’ when it comes to technologies being subsidized, the more high quality data available, the better.

While I haven’t looked over the study in detail, it does seem like the strongest objections raised against nuclear (which is ranked very badly) aren’t really about the environment or economics. The risk Jacobson highlights most is that of nuclear proliferation, and the dangers associated with making fissile material more widely available. Proponents of a nuclear renaissance probably won’t be keen to see discussion of “the emissions from the burning of cities resulting from nuclear weapons explosions potentially resulting from nuclear energy expansion.”

The entire study was published in Energy & Environmental Science, and can be accessed online.

A global response to the threat of asteroids

Climate change is not the only threat to humanity that the United Nations has been called upon to deal with. Another risk that bears consideration is that of the inevitable collisions that will occur between our planet and other big rocks in space. A group called The Association of Space Explorers has raised the issue recently, arguing that the near pass of Asteroid 99942 Apophis in 2036 should prompt some coordinated global thinking on appropriate responses to possible impacts. Their report refers the the Tunguska event of 1908, a three to five megatonne explosion which started fires large enough to engulf New York City. Apophis has a 1-in-45,000 chance of striking the Earth, but would generate a 500 megatonne blast if it did so. On an astronomical timeline, it is inevitable that an object of this magnitude will eventually strike the Earth.

The group has released a fifty page report entitled Asteroid Threats: A Call for Global Response (PDF). It covers both some technological options for deflecting incoming asteroids and decision-making processes through which such plans could be put into action. It makes a strong case that the probability of successful deflection is much higher if action is taken early. An extension of that is the need to take decisions before it is certain a collision will occur: a situation that significantly increases the probability that such a decision will need to be made within the foreseeable future.

Deleting images in iPhoto

Whoever designed the photo deletion interface in iPhoto rather botched the job. The system in both versions of iPhoto I have used (’08 and ’04) has been confusing and very easy to use incorrectly.

When you select a photo in an album and hit delete, it gets removed from only that album, not the photo library. This is sensible enough, though there should be an easier way to delete the image from both locations. What is much odder is that when you delete a photo from the library, it doesn’t go into the Mac OS trash. Instead, it goes into a custom iPhoto trash folder.

What is really unforgivable is that if you go into the trash folder, select an image, and hit delete, it actually gets returned to its original location. There have been plenty of occasions where I have gone through the photos from an entire trip (probably hundreds of images), removing the botched and boring ones. If you then hit the wrong key while looking at the trash folder, they all jump back to their original locations, and you need to repeat the whole selection process.

It would be far more sensible for iPhoto to behave like iTunes. When you delete a photo from the library, it should ask if you also want to delete it from your hard drive. Then, there is no need for an independent trash folder. Removed images would either get taken out of the iPhoto file management system but left in their original hard drive location, or they would be put into the general Mac OS trash. It should also be possible to delete images straight from smart folders. When a photo in such a folder is selected for deletion, it should automatically be moved to the Mac OS trash.

New tripod

For several years now, I have been wondering about the fate of the Manfrotto tripod that I purchased back near the very beginning of my photographic hobby. I remember the aluminum tripod and ball head costing more than my first SLR and lens: a Pentax MX Super with a manual 50mm lens. I left the tripod in a closet when I went to Oxford and haven’t seen it since, despite a fair bit of concerted searching during a couple of the periods when I was in Vancouver.

Due to a holiday promotion, I have bitten the bullet and picked up a new Manfrotto tripod. This one – a 725B Digi – is a bit smaller and lighter than my old one, through the overall design and construction is very similar. The two biggest things it lacks, in comparison to the one I hopefully still have in some obscure Vancouver corner, are (a) the ability to position the legs at any of three stable angles (due to push-in aluminum blocks) and (b) the option to invert the centre column for use very close to the ground. The biggest advantages are the somewhat smaller overall dimensions and lesser weight. Other differences include (a) a lever rather than a screw for tightening the centre column, (b) a different design for the lever that secures the ball head, and (c) four-segment legs rather than three-segment ones. The two models are different enough that I will not be annoyed if the old unit does turn up in the course of future rummaging.

Given the reality that I will be at work during most of the daylight hours between now and the spring, having a tripod on hand makes a lot of sense. It is also nice that this model is compatible with the tripod plates from the previous stabilizer, including those affixed to the bottom of my Elan 7N and Rebel G.

What Do You Care What Other People Think

This sequel to Richard Feynman’s Surely You’re Joking covers some of the same ground as the prior book, though it is focused on the inquiry conducted after the Challenger space shuttle disaster. The book includes an appendix to that report, written by Feynman exclusively. Apparently, he was going to remove his name from the findings on account of his section being censored. Eventually, they printed something largely identical to his final copy.

As he explains it, the solid rocket booster failure that destroyed Challenger was largely the result of disjointed and poor communication between layers of administration at NASA and its supplier companies. The statistical modeling of the behaviour of the O-rings in the boosters was very poorly done. Information on the vulnerabilities of the shuttle either did not reach the most senior levels or was paid insufficient heed there. In any case, it seems likely that even if cold weather and design problems hadn’t caused this specific failure, something would have eventually gone wrong anyhow. For example, Feynman describes in detail some technical and procedural issues associated with the main engines. Such problems are not really surprising, given the overall complexity of the vehicle, the ‘top-down’ manner in which it was constructed (designing whole systems before testing individual components), and its fundamentally experimental nature. That being said, Feynman’s assessment probably has continuing relevance for other projects with similar associated risks and management structures. In particular, the contrast he draws between the strong protocols used in programming the shuttle’s computer – as compared with the protocols for sensors and engines – demonstrates that it is possible to do things well, provided sufficient attention and resources are devoted to the task.

Overall, the previous book is more entertaining and shows more of Feynman’s character. Aside from a section on Feynman’s first marriage, as well as the illness and death of his first wife, this book focuses on the details of Feynman’s investigation, including his famous demonstration with the O-ring and glass of ice water. All told, I found the earlier book more diverse and interesting. This book may be more useful for those whose professional work involves dangerous machines.

Lens selection survey

Fellow photographers: if you had the following collection of SLR bodies and lenses, which piece of glass would you aspire to next?

Bodies:

  • Canon Rebel G film SLR
  • Canon Elan 7N film SLR
  • Canon Rebel XS digital SLR

In practice, I expect to be using the Rebel XS far more than the film bodies, from this point on.

Lenses:

  • Canon 50mm f/1.8
  • Canon 28-105mm f/3.5-4.5 USM II
  • Canon EF-S 18-55mm f/3.5-5.6 IS

Ideally, it should be useful for both full-frame and 1.6x factor, APS-C sized cameras. The APS-C equivalent focal lengths for those lenses are 80mm, 44.8-168mm, and 28.8-88mm. In general, I prefer the wide-angle look to the telephoto look, though I would be interested in anything that significantly expands the potential or usefulness of the SLRs above.