Keyboard worrier
Showing posts with label Science & Technology. Show all posts
Showing posts with label Science & Technology. Show all posts

Tuesday, September 10, 2013

Davy Jones' garbage



Look beneath your lid some morning,
See those things you didn't quite consume
The world's a can for
Your fresh garbage . . .

Spirit - Fresh Garbage[1] [2]

I loved that song when I first heard it in 1968, on the compilation LP “The Rock Machine Turns You On”[3] – Jay Ferguson’s distant, lost-sounding, disillusioned tenor voice, perfect for the teenager in turmoil.

It’s still relevant, and the biggest rubbish bin of all is the sea. A lot of this is plastic, not only on shores, where it represents 60% – 80% of all litter (Derraik, 2002[4]) but in vast swirling oceanic garbage patches[5] - and on the sea bed: in 1995 92% of debris on the floor of the Bay of Biscay was plastic[6]. A more recent article by Greenpeace says 70% of plastic litter sinks, and there is an estimated 600,000 tons of it at the bottom of the North Sea.[7]

The debris is unsightly, and can strangle or fill the stomachs of marine wildlife. It’s also toxic, so developing biodegradable versions doesn’t solve the problem – indeed, it could make it worse, since dissolved plastic is much harder to find and nearly impossible to remove.

James Higham posts a picture[8] of a cleanup device still under development. It’s a giant static filter that the inventor, Boyan Slat, hopes will trap surface garbage but allow plankton to pass safely through; work continues.[9] But even if it works perfectly, that still leaves the other, sunken 70% to deal with. Yet again, techno-fixes have limitations.

I can remember when we had shopping baskets and produce wasn’t shrink-wrapped. Will those days ever come again?
 


[1] http://www.metrolyrics.com/fresh-garbage-lyrics-spirit.html
[2] http://youtu.be/k7MQ5rxUZsc
[3] http://en.wikipedia.org/wiki/The_Rock_Machine_Turns_You_On
[4] http://www.caseinlet.org/uploads/Moore--Derraik_1_.pdf
[5] http://en.wikipedia.org/wiki/Category:Marine_garbage_patches. There are in fact more than three of them, as the articles go on to explain.
[6] Derraik, Table 1 (see note 4).
[7] http://www.greenpeace.org/international/en/campaigns/oceans/pollution/trash-vortex/
[8] http://nourishingobscurity.com/2013/09/09/plastic-gobbler-of-the-seven-seas/comment-page-1/#comment-221633
[9] http://www.boyanslat.com/plastic5/

All original material is copyright of its author. Fair use permitted. Contact via comment. Nothing here should be taken as personal advice, financial or otherwise. No liability is accepted for third-party content, whether incorporated in or linked to this blog; or for unintentional error and inaccuracy. The blog author may have, or intend to change, a personal position in any stock or other kind of investment mentioned.

Tuesday, September 03, 2013

Salt Power

Where river meets sea we have an opportunity to extract not just tidal energy, but energy derived from the difference between salt water and fresh. Maybe if energy policies were rational we wouldn’t have such opportunities, but we are where we are.



With pressure retarded osmosis, or PRO, the idea is to take advantage of the osmotic pressure created when river water and sea water are separated by a semi-permeable membrane.

Under these conditions, water molecules from the river pass through the membrane into the sea water, creating a pressure on the sea water side of the membrane which may be used to drive turbines and generate electricity.

A pilot plant in Norway which has been generating a few kilowatts since 2009. As with so many sustainable energy technologies, the problem is one of energy density. There simply isn’t much energy to be extracted from each square metre of membrane.

Huge areas of membrane, in the order of square kilometres may be required to scale up the technology, but these membranes are also prone to fouling, so the technical issues are formidable.
 


A less developed but simpler and perhaps more interesting way to extract energy from seawater and river water is Reverse Electrodialysis or RED.

In the RED approach, the osmotic energy of mixing fresh and salt water is captured by directing the solution through an alternating series of positively and negatively charged exchange membranes. The resulting chemical potential difference creates a voltage over each membrane and leads to the production of direct electric energy.

As with PRO, there are many technical hurdles and much research to be done, but a Dutch company called REDstack B V began work on a pilot plant in July. Both technologies are clean, highly modular and relatively well understood.

Could the Severn estuary be used to generate both tidal power and power from a technology such as PRO or RED?

We certainly have the ingenuity - pity about the politics.

All original material is copyright of its author. Fair use permitted. Contact via comment. Nothing here should be taken as personal advice, financial or otherwise. No liability is accepted for third-party content, whether incorporated in or linked to this blog; or for unintentional error and inaccuracy. The blog author may have, or intend to change, a personal position in any stock or other kind of investment mentioned.

Monday, September 02, 2013

A question for Ayn Rand followers

What is the point of "rational self-interest"? Everything you do for yourself is lost when you die.

Perhaps it's an observation rather than a precept.

But it needs unpacking - what's the self? What are the drives that count as "happiness"? Are you exercising your freedom by obeying your impulses?

Reminds me of what little I understand of Sartre. Having proved to his satisfaction that man is a futile passion, he then tries to build on the void - you should be brave, honest. Why? When you're gone, you won't be able to applaud yourself or stick any trophies on your ethereal shelf.

The "selfish gene", that I can understand. But that implies that the organism lives for the next generation and for others that share its genes, not itself alone.

We share about half our genes with bananas, I'm told.

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Haunting

http://xkcd.com/1259/
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Sunday, August 25, 2013

Fukushima radiation: "Don't buy Pacific fish"

One of John Ward's scientific correspondents tells him:

"I would also advise your Sloggers, not to buy fish products, salmon, tuna, sushi from the Pacific: as the Caesium plume spreads, the chances of ingesting contaminated fish will grow, and it will be interesting to ascertain what measures government is taking in this regard….”

Back in May, BBC News reported how Pacific tuna have absorbed radioactive material in their oceanic wanderings. The reporter was at pains to say that the fish were still safe to eat. There are further reports here.

I am less inclined to accept scientific reassurances than I used to be. I recall how the UK nuclear reactor at Windscale (since renamed Sellafield to shake off poisonous memories) was thought to be safe, and local schoolchildren would sometimes go up to the site to led condensation droplets fall into their mouths. Later, perhaps after the fire there that was covered up, scientists moved their children away from the nearby school but did it quietly, so as not to scare the general populace. I'm sorry, but although I recall the information I can't now find the references to back this up. The main point is, we don't always know how safe things are and when concerns develop we commoners are not kept abreast.

There are reports of fish - Pacific herring - bleeding from eyes and gills. Now this may have nothing to do with radiation (think of the great swirling garbage patches - there's more than one - in the oceans, and stretches of oxygen-depleted and algae-covered sea); or if there is a connection, it may be indirect, like the way that pesticides may weaken the defences of bees, rather than killing them outright.

A core issue is our degree of trust in the openness and competence of governments and scientific agencies.

All original material is copyright of its author. Fair use permitted. Contact via comment. Nothing here should be taken as personal advice, financial or otherwise. No liability is accepted for third-party content, whether incorporated in or linked to this blog; or for unintentional error and inaccuracy.

Tuesday, August 13, 2013

Would you notice?

From Bloomberg Businessweek

Xerox is now saying that some of its scanners can alter numbers in documents, even at the highest resolution setting. It blames a software bug for which it does not yet have a fix. “We continue to work tirelessly and diligently to develop a software patch to address the problem,” the company said in an Aug. 11 statement.

The problem came to light when German computer scientist David Kriesel scanned a construction plan on a Xerox machine and noticed that it changed numbers on some of the room measurements.


Would you notice such a thing? I'm not sure I would.

All original material is copyright of its author. Fair use permitted. Contact via comment. Nothing here should be taken as personal advice, financial or otherwise. No liability is accepted for third-party content, whether incorporated in or linked to this blog; or for unintentional error and inaccuracy. The blog author may have, or intend to change, a personal position in any stock or other kind of investment mentioned.

Thursday, August 08, 2013

Not enough O2 in the H2O?

Adam Nieman: "Global water and air volume" (Science Photo Library)
Professor Jason Box is continuing his research into the effect on Greenland snow melt of particulates from fossil fuel burning and forest fires, and this set me wondering about how much atmospheric oxygen is being locked up by the same processes.

O2 levels have varied radically during last 600 million years:

(from Wikipedia article "Atmosphere of Earth: Third Atmosphere")

- as corroborated by analysis of ancient gas bubbles trapped in amber.

Writing in the Guardian newspaper in 2008, Peter Tatchell said that research by Professor Robert Berner suggested "humans breathed a much more oxygen-rich air 10,000 years ago", though I can't track down the original statement and suspect Tatchell may have misunderstood. (A paper by Berner on oxygen in the Phanerozoic era can be read here.)

Tatchell appears to be on firmer ground voicing concerns about air quality in cities, though what's in the air is more worrying than what's absent, as this article from last month's Mail Online India edition says. That said, cities that are prone to temperature inversion layers (e.g. Los Angeles, Beijing) may find that not only is smog locked in, but oxygen not replenished from the surrounding area as fast as it is being consumed.

Globally, there seems to have been a very small decline in atmospheric oxygen since 1990, according to an 18-year longitudinal study by Dr Ralph Keeling. According to a post on the Climate Emergency Institute website, the decline is even less than Keeling had expected, and it's possible that increased CO2 is stimulating the growth of vegetation.

Certainly the self-styled "Rational Optimist" Matt Ridley claims greenery is increasing, but I am inclined to take his professional bullishness with a pinch of salt. Surface spread as seen by satellite misses the third dimension: the UN FAO estimates (2012 forest report) that forest cover has dropped by around a third in the last 10,000 years, and the loss has accelerated from an average of 360,000 hectares per year since civilization began, to 5.2 million annually over the last decade.

Which brings us back to the carbon dioxide-global warming debate. CO2 is a "greenhouse gas" but there are so many other factors affecting the Earth's surface temperature that I don't think anyone can say which way the thermometer is going to move. However, if the sea continues to warm up there is a danger that the level of dissolved oxygen in the oceans will be reduced. A study reported last year in Science Daily says that 15% of the seas are "dead zones" and suggests that an increase of a couple of degrees - as has happened since the end of the last Ice Age - can have significant effects. Again, industrial pollution and waste dumping exacerbate the damage.

http://peswiki.com/index.php/Directory:Oxygen_Depletion

The Tatchell article also refers to a claimed 30% drop in oceanic oxygen-producing phytoplankton in the thirty years since 1980, though this is disputed. Even if true, our gas tank will keep us going for the foreseeable future: the Earth's atmosphere has a total mass of some 5 quadrillion (1015) tonnes, a fifth of which is oxygen. There's so much that the CEI article concludes "even when fossil fuel reserves (mostly coal) are exhausted, the maximum potential loss in oxygen is only small (Broecker, 1970)."

Further, as this 1994 paper by Duursma and Boisson says:

"Oxygen concentrations are ... the consequence of larger terrestrial and aquatic loops in which factors of temperature, light, nutrients and co2 play a role; for longer periods, elements such as sulphur and iron are involved. Hence the present level of 20.946 vol. % of atmospheric oxygen is merely temporary, and will change in the course of millions of years. The question of an optimum concentration for sustaining life on earth is equally time-dependent; but bearing in mind that these changes occur over periods of the order of millions of years, evolutionary processes are likely to keep pace with oxygen changes."
Those evolutionary processes may or may not have a place for humanity in the long run, but we have plenty more pressing threats to worry about. One of which is that the health and productivity (for us) of the seas may be compromised if warming continues and subsurface oxygen is depleted.

All original material is copyright of its author. Fair use permitted. Contact via comment. Nothing here should be taken as personal advice, financial or otherwise. No liability is accepted for third-party content, whether incorporated in or linked to this blog; or for unintentional error and inaccuracy. The blog author may have, or intend to change, a personal position in any stock or other kind of investment mentioned.

Tuesday, August 06, 2013

Driverless trucks and their social implications

"Mish" reports on the development of automated trucks, with what appears to be econohawkish glee - oh, the savings we'll make.

But this will be replicated not just in blue collar jobs but the white collar middle class that until recently felt their college degrees and head-expertise insulated them from the uncertain and lower-paid employment of their socioeconomic inferiors. Even fund managers might easily be replaced by machines, as I understand arm-waving, shouty stock market traders are being right now.

The debates over State benefits and the redistribution of wealth are likely to become more lively in the years to come, and people who used to take one side may surprise themselves by crossing the floor.

Besides, when few have a job, how will the demand for goods and services be affected? Business owners need not be complacent, either.

Is the future in community policing and shopping at LIDL?

All original material is copyright of its author. Fair use permitted. Contact via comment. Nothing here should be taken as personal advice, financial or otherwise. No liability is accepted for third-party content, whether incorporated in or linked to this blog; or for unintentional error and inaccuracy. The blog author may have, or intend to change, a personal position in any stock or other kind of investment mentioned.