Geek stuff – Page 89 – a sibilant intake of breath

Carbon-neutral aviation

The climatic impact of aviation

At present, virtually all freight and passenger-carrying aircraft operate in one of two ways: burning kerosene to turn a propeller, generating thrust that the wings partially convert to lift, or generating thrust by burning kerosene in a jet engine. Virtually all of that kerosene is produced by refining petroleum. As such, burning it adds to the stock of greenhouse gasses in the atmosphere. These include carbon dioxide (CO2) (a basic product of the combustion) and other greenhouse gasses (GHGs), like nitrous oxide (NO2). It is also possible that aircraft have an effect on cloud formation (both by producing vapour trails and inducing cirrus cloud formation), but my understanding of the science is that scientists aren’t sure whether that has a net warming or a net cooling effect. The latest IPCC report says:

Moreover, the uncertainties on some aviation forcings (notably contrail and cirrus) are still high, such that the overall radiative forcing consequences of changing cruise altitudes need to be considered as a time-integrated scenario, which has not yet been done. (p. 355)

Helpfully, the report does identify that, if contrails prove to be a significant problem, they “can be easily avoided – in principle – by relatively small changes in flight level, due to the shallowness of ice supersaturation layers.” There is also some uncertainty about the relative emissions of short-lived but potent GHGs like nitrous oxide, compared with long-lived but less potent ones like carbon dioxide. All told, the report does conclude that aviation has a “larger impact on radiative forcing than that from its CO2 forcing alone.”

Carbon neutral possibilities

A couple of logical possibilities exist for making air travel carbon-neutral, though they differ in practicality. Electric planes are conceptually possible, and small versions exist. As I understand it, the big problem is storing enough energy in light enough batteries. My sense is that we are nowhere near being able to do this for large commercial aircraft. Similar issues exist for hydrogen aircraft, in term of storage, and there is the added question of where we get the hydrogen. To me, biofuels seem like the most plausible near-term option. That being said, there are technical issues to be overcome within aircraft themselves, such as the gelling of biofuels at the low temperatures found at high altitudes. While some airlines have tested multi-engine planes with a single engine running on a biofuel/kerosene mix, as far as I know nobody has flown such a plane exclusively using biofuels.

Additionally, not all biofuels are carbon neutral. Ethanol derived from corn might actually represent more greenhouse gasses than an equivalent amount of gasoline, once you factor in fertilizer production, emissions from farming and farm equipment, ethanol fermentation, etc. The same might be true of palm oil derived biofuels, given how their production can lead to the destruction of rainforests that are major carbon sinks.

My sense is that the air travel industry has yet to demonstrate that it will be able to exist in a carbon neutral world, regardless of how expensive tickets become. That being said, it does make sense to displace emitting activities in order from lowest cost to highest cost. If we can replace fossil fuelled ground vehicles with electric vehicles running on renewable power, we should do so first before pouring enormous effort into trying to produce a carbon neutral aircraft. That being said, there does seem to be a strong moral imperative to reduce emissions generally, including by limiting the amount of long-distance travel we undertake.

As usual, I expect any mention of aviation to produce a lively discussion.

The Desertec solar plan

As reported in The Economist, Munich Re has invited 20 large companies to form a consortium, intended to build concentrating solar power stations in Africa and the Middle East, as well as the high voltage direct current (HVDC) lines required to bring that power to Europe. The stations will use molten salt heat storage, so as to be able to generate power day and night. Munich Re, the world’s largest reinsurer, is motivated by concern about its exposure to climate change. Fully implemented, the scheme would cost $560 billion and provide 15% of Europe’s projected energy demand in 2050. The complete system would cover 17,000 square kilometres of territory.

Desert solar as a renewable energy option has come up here before.

All told, the plan is very promising. It is refreshing to see companies thinking strategically about the long-term harm climate change could do to them, as well as the long-term opportunities associated with renewable energy. A report produced by the Wuppertal Institute for Climate, Environment and Energy and the Club of Rome determined that the project could produce 240,000 jobs in Germany, as well as €2 trillion worth of electricity by 2050.

Even more importantly, it could demonstrate the feasibility of the desert concentrating solar / HVDC option, which could be extended to the Southern US and elsewhere. As David MacKay explains, this is one of the renewable options where the figures add up, and it could be possible to generate the kind of energy societies demand. Here’s hoping the Desertec plan helps lead the way.

Insight into Google

For someone who produces a site which covers a broad variety of topics, Google is an especially critical source of traffic (because people interested in one topic are unlikely to follow a site with a bunch of other random topics included). In my case, more than 60% of the traffic I received in the last year came as the result of Google searches. No other search engine produces more than 3.5%, and only 12% of visitors actually type in the URL, rather than clicking a link from a page of search results or another site.

Given the importance of Google, it is worth knowing a bit about how the organization operates. Over at All Things Digital, there are three interesting articles. The first covers the human evaluators Google uses to evaluate the effectiveness of their various search algoriths. The second discusses the attempts people make to game the system (inevitable, given the sheer amount of money that can be gained or lost by rising or falling in Google rankings). The third describes how Google intends to improve future search results.

One interesting fact mentioned in the first piece is that the option Google offers for users to hide results in their searches is used to refine their search algorithms. For instance, I am personally annoyed by websites that try to scrape together an identity page on someone, by grabbing snippets from here and there that seem related to them. Sites that do this include pipl.com, 123people.co.uk, zoominfo.com, and others. It is a bit encouraging that if enough people hide their unsolicited and error-prone amalgamations, their overall page rankings may eventually suffer.

Differential electricity pricing

Some forms of differential prices based on time are entirely artificial: for instance, telephone companies that charge more for calls made before 6:00pm or 7:00pm. They do this because it is profitable. It lets them charge high prices during the day to business users, while offering cheaper plans to social users later. That being said, there are situations where the economic basis for prices varies considerably depending on time of day (and year). Electricity production is one.

In the future, spikes in electricity demand may be partially mitigated through the combination of variable pricing and smart appliances that can inform users about the costs of operating at different times, or even make autonomous choices to stay within a budget. This video from General Electric provides more information.

While getting rid of daytime minutes would have little real effect on cell phone networks, shifting electricity demand from high-demand to low-demand times could have a significant impact on the electrical system, partly by reducing the need for inefficient ‘peaker’ plants, which top up supply during periods of maximum strain.

Ophcrack and Windows passwords

As mentioned before, rainbow tables are a mechanism that can be used to reverse hash functions, revealing information that was intended to be hidden. For instance, they can take the hashed contents of a Windows password file and turn them into a password you can use. This limitation largely exists because Windows does not use the technique of ‘salting,’ which would make rainbow tables unmanageably large. Unix-based operating systems, like Mac OS X, have been salting passwords since the 1970s.

Ophcrack is a piece of free software that exploits precisely this vulnerability. As explained here, it comes as a bootable CD, which can be used to circumvent the password on a Windows XP, Vista, or 7 computer.

Among other things, this means that having a password-protected user account isn’t an adequate way to protect your data from anyone who can get their hands on your computer: from customs agents to burglars. If you have anything sensitive in there, it would be sensible to further protect it with some strong encryption.

Numerical puzzle

Simon Singh, several of whose books I have reviewed before, had a mathematical contest where he was seeking numbers that fit this pattern:

A^(B+C)=BCA

For example, 5^(1+2)=125.

The contest closed yesterday, but it is still something people might want to play with. I found three additional solutions, listed below in AES (with the key ‘answers’). I also proved that there are no solutions other than the one above and those below. Continue reading “Numerical puzzle”

Don’t bring cameras to concerts, bring binoculars

Going to see Neko Case and Ani DiFranco at Bluesfest reminded me how, these days, 1/3 of the audience will be trying to capture everything on their cell phone cameras, while another 1/3 will be trying to do so with low-cost digital SLRs and cheap zoom lenses. It is only fair to point out that neither will produce photos of remotely comparable quality to concert images of the artist you could find using Google or Wikipedia in a couple of minutes.

Say you want to engage with the experience using hardware that will produce output of good optical quality. There are at least two routes open to you:

1) Still camera:

Buy a crazy lens. Two options to consider are the Canon EF 100-400mm f/4.5-5.6L IS USM (US$1,575) and the Canon EF 600mm f/4L IS USM (US$$7,650).
Buy a good quality filter to protect the expensive front element ($60-80).
Buy a camera body that produces good images at high ISO. An excellent option would be the Canon 5D Mark II (US$3,900).
Attach your 1.4kg lens to your 820g body.
Get both past security people wary of commercial photographers.
Worry a lot about the $5,000 to $10,000 worth of gear around your neck, as well as spinal damage from the 2kg weight.
Get fairly close to the stage, and spend the concert concerned about AE correction for changing backdrops, flare from stage lights, etc. Worry also about the limited dynamic range of your digital sensor, white balance issues, and the fact that most photos of people singing come out looking awkward.

In short, unless you are being paid to document the concert, or happen to already own the appropriate gear, this isn’t a terribly appealing option.

2) Binoculars:

Buy some moderately priced binoculars. Good options include Bushnell 8×25 Binoculars (C$50) or, even better, Pentax 8×21 UCF-R Mini Binoculars (C$58).
Carry your 200g binoculars through security.
Find a spot about a bus-length from the performer.
Enjoy watching them in high resolution, full frame, full motion video.
Note, also, that they will be in three dimensions, with an even more flattering depth of field effect than the monocular version offered by the best zoom lenses.

For less than the cost of a filter to protect a crazy lens, you can buy an optical instrument that can contribute more to engagement and enjoyment than the whole photo setup. Concert lighting is set up to look good to human eyes (the relevant sensor when using binoculars), not digital sensors (the ultimate target of photos flying through your expensive photo rig). Wearing your crazy photo rig, you will feel like part of the paparazzi. With good binoculars, you will feel like a falcon.

While you will probably never be able to take a better photo of a performer than you can readily find online, you can quite easily watch them with your own wonderful eyes at a much higher quality level.

P.S. Neko Case is a very strong live performer. Her on-stage renditions of songs are remarkably similar to her studio albums. I found that Ani DiFranco is really amazing on stage, even though I am less familiar with her music. She has wonderful spirit, lots of technical skill, and a notable ability to engage with the crowd.

The JFK library’s Apollo tribute

The John F. Kennedy Presidential Library has come up with a pretty cool way to mark the 40th anniversary of the Apollo 11 mission: they are making a real-time re-creation available at WeChooseTheMoon.org, complete with historic footage, photos, and interactive elements.

The site is definitely rather slick, and includes some material I hadn’t seen elsewhere before. The Boston Herald has a more detailed description.

‘Sexy’ studies, the media, and scientific certainty

A post on RealClimate identifies some problematic aspects of science reporting, such as how the media preference for new and surprising information means that spectacular and unreproduced studies can get more attention than those that have been carefully examined and replicated:

The more mature and solid a field, the less controversy there is, and thus the fewer news stories. Ironically, this means the public is told the least about the most solid aspects of science.

The whole post is worth reading.

The consequences of this tendency are probably pretty serious. For one thing, it makes science seem less credible than it otherwise would. One day, scientists say red wine is good for you, the next day they seem to say something else. We would all be better off if the most authoritative studies, such as the work of the Intergovernmental Panel on Climate Change or the systemic reviews undertaken by the Cochrane Collaboration, were represented as such in the mainstream media, as well as if individual unconfirmed studies were described with an appropriate focus on methodology, and an awareness that those studies which are new, surprising, and contradict well-established hypotheses are often later shown to be incorrect or of limited application or importance.

I also like the rule of thumb the post attributed to Richard Feynman: “the last data point on any graph should be discounted because, if it had been easy to obtain, there would have been another one further along.”

In Mortal Hands

Stephanie Cooke’s In Mortal Hands: A Cautionary History of the Nuclear Age is a four hundred page account of the major problems with the global nuclear industry, both civilian and military. It argues that the costs associated with both nuclear weapons and nuclear energy have been hidden by self-interested governments and organizations, and that nuclear energy should not be part of our future energy mix, despite concerns about climate change and energy security. The book’s unceasingly critical position leaves one longing for a more comprehensive account, where arguments in favour of nuclear energy would at least be more comprehensively rebutted. Nonetheless, Cooke’s book does a good job of reminding the reader of the many special dangers associated with nuclear energy, and the risks associated with re-embracing it, due to our concerns about fossil fuels.

In Mortal Hands argues convincingly that most of the costs associated with nuclear energy are hidden, and not borne by the utilities that provide it or the people that use it. These costs include wastes, contaminated sites, decommissioning of plants and related facilities, risks of accident, nuclear proliferation, providing targets to enemies and terrorists, routine radioactive emissions, the redirection of capital and expertise from potentially more positive uses, and the further entrenching of secrecy and self-serving pro-nuclear entities within government and industry. Certainly, the issue of secrecy is an important one. Along with concealing costs and subsidies, it is demonstrated that the nuclear industry has misled policy-makers and the public about the risks associated with the technologies, timelines and costs associated with the emergence of new technologies like reprocessing and ‘breeder’ reactors, and the number and severity of nuclear accidents. The industry knows that another Chernobyl or Three Mile Island could undue their anticipated ‘renaissance,’ so they are arguably less likely than ever to disclose accurate information on dangers, or on incidents which do occur. Governments that authorize, encourage, and fund new nuclear facilities will be in a similar situation, in terms of the harm awareness of risks and accidents could do to them politically.

Cooke raises a number of important points about regulation, both nationally and internationally, and the conflicts that exist between commercial pressures to get reactors sold and keep them running and concerns about safety and proliferation. None of the big nuclear states has a good record on preventing sales to states secretly working on nuclear weapons. Lack of toughness on the part of international and national regulators is a major reason why countries like Israel, South Africa, and North Korea have been able to use the cover of civilian nuclear programs to get themselves nuclear weapons. Lack of rigour is also clearly evident in nuclear programs, in terms of making sure facilities have been built and operated properly, bombs are secure, and the massive contamination is avoided.

The book is arguably weakest in its discussion of technical matters, which are not discussed at great length or in a way that seems entirely credible and convincing. Opportunities to elaborate and justify claims made about technical matters are often missed, and the book includes at least a few claims that seem likely to be erroneous. For instance, Cooke misrepresents where most of the energy in a thermonuclear explosion comes from, and fails to point out that the START-II agreement never went into effect. More than a discussion about the physics and engineering of nuclear technology, this book focuses more on the regulatory, political, and economic aspects. While that might annoy those with more technical inclinations, it is probably the right approach for a volume with the ultimate intention of informing public policy choices about whether to use nuclear energy for electricity production.

Cooke’s response to the question of how the energy currently being provided by nuclear plants could be replaced is especially unsatisfying. Essentially, it is: “Wind energy is growing very quickly, and perhaps distributed microgeneration could be the solution.” Some consideration of scale, such as that provided by David MacKay, is essential here. Small wind turbines on the roofs of houses as not a viable alternative to gigawatts worth of reactors. At the very least, those who advocate using renewables in place of nuclear need to recognize the enormous scale of deployment that would require, and the various associated costs. While Cooke’s book does not provide a sufficiently broad-minded basis for reaching a final judgment on nuclear energy, it is a convenient antidote to some of the current industry messaging that new plants will be safe and cheap, proliferation isn’t much of a concern, and even Chernobyl wasn’t so bad.