science

Robug IV The rise of the machines?

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2012/18/1 Prototype walking robot, Robug IV, designed and made at the Department of Mechatronics, University of Southern Queensland, Australia, 1995-1999. Collection: Powerhouse Museum

The Powerhouse Museum has an impressive and growing collection of robots. From a nineteenth century automaton to the Articulated Head currently featured in the Galleria section of the Museum, the study and collection of robots is something the Museum’s science curators take seriously, but also have an enormous amount of fun with; I mean, they’re robots!
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What’s the link between Apollo 16, a Soviet Moon mission and the Powerhouse Museum?

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40 years ago, Apollo 16 landed in the Descartes region of the central lunar highlands. Image Courtesy NASA

This might sound like the set-up for a joke, but there really is a connection between the museum, NASA’s Apollo 16 mission and the USSR’s Luna 20 lunar sample recovery mission.
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An Australian relic from Leichhardt’s exploration of the interior

Published by Geoff Barker 0 Comments Tags: , , , , , , , , , , , , , .

Drinking cup, used by James Calvert. on Leichhardt’s expedition from Brisbane to Port Essington,1844 -1845, Powerhouse Museum, NN10265

It may be hard to imagine now, but once this cup must have been one of the most important things in the life of James Snowden Calvert. Around 165 years ago this cup travelled with Calvert and Leichhardt on the first overland trip from Brisbane on the east coast of Australia to Port Essendon on the west coast. On this trip across the dry and dusty interior water was often in short supply and the ration handed out to Calvert in this cup must have been one of the highlights of each day. Perhaps this was the reason he kept the cup as a memento of the hardships they shared on this, the first of Leichhardt’s expeditions.

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World Meteorological Day – early meteorology in Australia

Published by Geoff Barker 0 Comments Tags: , , , , , , , , , , , , , , , .

Lightning strikes on the Sydney Harbour, 7 December, 1892. The photograph was exposed over four minutes giving an impression of five separate strikes. Government Astronomer H C Russell calculated the height of the Darling Harbour flash from the cloud to the water to be approximately 1540 feet.

Lieutenant William Dawes, who came out to Australia with the First Fleet, made the first recorded meteorological observations in Australia but the next set were probably made from Parramatta Observatory between October 1822 and March 1824. 

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A fun map for Mercator’s 500th birthday

Published by Debbie Rudder 1 Comment Tags: , , , , , .

Powerhouse Museum Collection. Object A7624.

This map, drawn according to Mercator’s principle in 1795, is part of a board game. Spin a number, embark on a virtual journey heading south-east from the Azores, experience success and setbacks, learn some geography, and perhaps win by being first to arrive in London, the city where Bowles Geographical Game of the World was created.

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A battery that you can ‘refuel’ instantly: the vanadium flow battery

Published by Debbie Rudder 2 Comments Tags: , , , .

This post is part of an ongoing series of energy storage posts by intern Brett Szmajda.

Walking into the Castle Hill stores of the Powerhouse Museum is like walking into the prop warehouse of a Hollywood movie studio. You enter through a nondescript door in a modest, unassuming looking set of buildings, and when you turn around you encounter a cornucopia of steam engines, Mardi Gras floats, flywheels the size of a Mini Cooper, and exotic old X-ray machines that could be used for set dressing in a Frankenstein remake. The air is crisp and clean from the climate control system; the objects are neatly ordered and tagged, on stacks as high as a giraffe. We round a corner, and we come across an object that looks as if a drawer full of hanging files got intimate with the plumbing section at Bunnings.

“Take a look at this.” says Debbie.
“What is it?” I say.
“It’s one of the most promising battery technologies of the last 20 years,” she begins.

The vanadium flow battery.

The vanadium flow battery is a brilliant archetype of the trials and triumphs that accompany research and development. Throughout the development, led by Professor Maria Skyllas-Kazacos at the University of New South Wales in Sydney, research momentum was maintained by the phenomenal theoretical promise of the battery. Imagine a fully electric car that you could ‘recharge’ in a matter of minutes. Imagine a battery that would let small businesses and power companies store cheap energy generated at night, and use that power during the day, when energy is expensive.

A typical rechargeable battery contains two electrodes of differing material, immersed in a liquid electrolyte; chemical reactions occur between the differing metals of the electrodes, mediated by the electrolyte. But in a flow battery, like the vanadium battery, the principal chemical reactions instead occur between two liquid electrolytes. These electrolytes are pumped past one another (hence the name flow battery) in separate chambers that are separated by a thin membrane. As the two electrolytes flow past one another, they exchange ions (charged molecules) across the membrane, and this generates current.

Close-up of the exterior of the vanadium battery cells, where the electrolytes interact with each other.

To understand the difficulty in designing a flow battery, consider how your lungs extract oxygen from the air, and remove waste carbon dioxide from your body. Inhaling causes thin-walled sacs in your lungs (called alveoli) to inflate. Alveoli are surrounded by clusters of blood vessels; oxygen diffuses across the thin alveolar membrane, into the blood. Simultaneously, carbon dioxide diffuses from your blood into your lungs, to be exhaled. It’s critically important that the blood and air are kept in separate compartments (failure to do so would of course be fatal), and only selected molecules — oxygen and carbon dioxide — are allowed to pass through. Analogously, the challenge of designing a flow battery is making a membrane that will allow current to flow between the different electrolytes, but that doesn’t let the two electrolytes mix. The vanadium battery wasn’t the first flow battery, but it was the first to use the same metal in both electrolyte solutions, thus neatly eliminating the problem of electrolytes mixing across the membrane.

Golfcart powered by vanadium battery, used as a prototype during battery development.

The unique strengths of the vanadium battery are a short recharge time and the ability to store charge efficiently for long periods. The vanadium battery can be quickly recharged at high voltages; or — perhaps most attractively — it can be instantly recharged by replacing the electrolyte with fresh, charged electrolyte. Second, by pumping the electrolytes out of the ‘cells’ (where the reactions take place) and into storage vats, the vanadium battery can sit for many hours, with no self-discharge. These two attributes suggested potential commercial applications. For the consumer, there could be electric cars that you refilled with vanadium ‘fuel’ instead of gasoline; and for the business customer, the vanadium battery could be used as energy storage for the electric grid, allowing arbitrage (charge batteries when electricity is cheap, use battery power when electricity is expensive) and providing stability during intermittent drops in power supply.

Vanadium batteries have found a home providing energy storage for power stations, with several stations world-wide trialling the technology. Unfortunately, the harsh light of reality intruded on the dream of vanadium-fuelled cars — vanadium batteries are expensive to manufacture, have problems operating at low temperatures, and no battery to date has an energy density (that is, power per unit weight) that can compete with the fantastic energy density of petrol. But research continues: scientists have recently boasted numerous improvements to the energy density and temperature tolerance of vanadium batteries. Don’t give up on the dreams of the vanadium car.

What Goes Up Must Come Down

Published by Kerrie Dougherty 1 Comment Tags: , , , , .

Satellite fragment, one of 2, titanium / vanadium / aluminium, maker unknown, USSR, found in New South Wales, Australia, 1957-1972,
height 340 and width 379mm. Collection: Powerhouse Museum

Somewhere between 5 and 6am on Monday morning (Sydney time), Russia’s ill-fated Fobos-Grunt space probe disintegrated on re-entry into the Earth’s atmosphere, most likely over the southern Pacific Ocean off the coast of Chile (a summary of information about the Fobos-Grunt re-entry can be found on the Planetary Society blog . This was the third re-entry of a large defunct spacecraft since last September (the other two being NASA’s UARs and the German ROSAT), all of which attracted considerable media attention due to their size and potential to cause serious property damage or injury if their debris impacted in a populated area.

The danger from space debris to any individual is actually quite low, since a re-entering satellite is more likely to disintegrate over the oceans than over the land, and large tracts of the Earth’s land masses are very sparsely inhabited. In fact, dead satellites, spent rocket stages and other items of space debris regularly re-enter and burn up without creating any hazard, although fragments of space debris large enough to survive re-entry and reach the ground are not uncommon, with a handful of finds reported every year. These pieces of space junk are often found in remote areas or washed up on beaches after impact in the sea and can be quite perplexing for their discoverers. The Powerhouse receives a couple of enquiries every year from people who think they may have found a piece of space debris, or are just not sure what the strange piece of burnt material or slagged metal they have discovered might be. I recall one enquiry from a person who thought they had found a piece of space junk in the bush-but it turned out to be a dumped chunk of catalytic converter from a car engine!

94/254/1Space debris, Skylab space station, titanium/fibreglass, McDonnell Douglas Astronautics Co, USA, 1970-1972, height 810, width 1120 and depth 900mm. Collection: Powerhouse Museum

In its collection, the museum holds a piece of the Skylab space station, which re-entered over the Indian Ocean and Western Australia in 1979. I’ve written about this artefact and the unusual story of its discovery in a previous post. Another piece of space debris is currently in display in the Space exhibition, one of two fragments that the museum acquired as a donation from the finder in 1972. This partly-melted metal sphere is one of three similar objects that were found on Dobikin merino stud, near Bellata in northern NSW, in 1972. Two spheres were found in late September of that year, with the third being discovered in mid-October. At two of the impact sites, scorched and burned grass testified that the spheres were extremely hot when they landed.

In the 1960s and early 70s there were several finds of space debris in Australia. A report on the Bellata spheres from the Weapons Research Establishment (which is part of the documentation provided to the museum by the donor, Dobikin stud manager Mr. J. T. Vickery), lists seven ‘space objects’ that had been found and reported between 1963 and 1973. This is perhaps not surprising as Australia’s landmass covers a wide horizontal swath of the Earth’s surface. All these items were spherical pressure vessels, their shape better suited aerodynamically to survive the stresses of re-entry, and showed varying degrees of melting and other re-entry damage. They would have originally contained gases or cryogenic liquids.

When the first ‘space ball’ was found on Boullia Station in far western NSW in 1963, media speculation as to its origins ranged from evidence for an advanced ancient lost civilisation in Australia, to debris from a damaged UFO and “Boullia Ball” became a nickname for this type of spherical object found in Australia and New Zealand (some were found across the Tasman in 1972). However, investigations of the Boullia Ball and later space debris finds by the Weapons Research Establishment (WRE), Australia’s defence science agency and forerunner of today’s Defence Science and Technology Organisation (DSTO), demonstrated that they were of definite terrestrial origin, mostly from US launch vehicles.

The first two “Bellata Balls” were sent to the WRE for examination and it was established, on the basis of the type of weld used in their construction, and lettering on one ball in the Cyrillic alphabet, that the pressure vessels had originated in the USSR. In the Cold War environment of the time, the Embassy of the USSR in Canberra declined the WRE’s invitation to inspect the balls and confirm their origin, but there is little doubt about the identification. After examination, the WRE forwarded the two balls to the museum in 1973, in accord with Dobikin manager Mr. Vickery’s wish to donate them to the Museum of Applied Arts and Sciences. The third ball discovered remained in Mr. Vickery’s possession.

The two Bellata balls donated to the museum are made of a titanium/vanadium/aluminium alloy, a relatively light but strong metal. The sphere on display in the Space exhibition is the most complete of the two, although it was partially melted away and shows a jagged rim slagged with congealed metal. The body and interior of the ball are spattered with other blobs of metal slag, but it is otherwise reasonably intact. The other sphere was burned through in two places, so the WRE decided to cut it into pieces for examination and analysis: only a segment of the original now remains, stenciled with lab markings.

B2093-2 Satellite fragments (2), titanium / vanadium / aluminium, maker unknown, USSR, found in New South Wales, Australia, 1957-1972, height 195, width 390 and depth 360mm. Collection: Powerhouse Museum

Finds of space debris, tangible items that have been in space and thus are imbued with the mystique of space exploration (however mundane their actual role) continue to fascinate the public and the media. They are also important reminders of an issue that is assuming increasing significance-the dangers to operational satellites from the remnants of old satellites littering the most useful orbits. This is a topic that I’ll address in a future blog post.

A hot topic: Solar Thermal Power

Published by Debbie Rudder 1 Comment Tags: , , , .

This post is part of an ongoing series of energy storage posts by intern Brett Szmajda.

When I say ‘solar power’, most people conjure up images of the thin, iridescent blue panels that make a patchwork quilt out of the roofs of suburban houses. But photovoltaic solar power — converting the sun’s rays directly to electricity — is a youngster in the field of solar energy. Its great, great grandfather is solar thermal power; and with the looming threat of climate change, heat from the sun could be a significant part of Australia’s renewable energy transformation.

Solar Heater by Lawence Hargrave

The principle behind solar thermal power should be familiar to anyone who has ignited dry leaves with a magnifying glass. Solar thermal power utilises the heat from the sun’s rays to do useful work. This object from the collection, invented by Lawrence Hargrave, illustrates the Australian inventor’s early attempts to heat water using the sun’s heat. Sunlight is focused by the conical dish onto the central pipe, which is closed at one end so it can hold a small volume of water. As best as we can tell, this was a hobby or proof-of-concept by Hargrave, who was also making small steam engines. However, around the same time as Hargrave was toying with solar, inventors on the other side of the world were patenting larger solar water heaters that could heat water for a household.

Utility companies have taken these basic small-scale ideas and supercharged them, creating solar thermal power stations to yoke the sun’s heat and turn it into electricity. (There are many alternative designs; most involve a lot of mirrors). For example, ‘power tower’ solar thermal power plants use several hundred mirrors to concentrate the sun’s rays on a central tower containing a column of water; this causes the water to boil, producing steam that drives a turbo-generator.

A 'power tower' solar thermal station. Image by Flickr user afloresm, reproduced under Creative Commons licence.

The big problem for solar thermal power generation is that sunlight isn’t constant — a solar thermal plant must contend with clouds, inclement weather, and of course, nightfall. The Solar Tres power plant (a ‘power tower’ design) in Andalusia, Spain has overcome this using a novel form of energy storage: molten salt. Instead of heating water directly, sunlight is concentrated onto a column containing a mix of 60% sodium nitrate and 40% potassium nitrate. The heat from the molten salt boils water and turns a turbine, as usual. The advantage of this additional step is that the molten salt can store the accumulated heat (for the electronics junkies in the audience, it’s almost like a ‘heat capacitor’). So when the sun goes behind the clouds or night falls, the heat from the molten salt continues to boil water, turning the turbine and keeping the power flowing. The simple addition of molten salt to the system allows 15 hours of heat storage, meaning that Solar Tres can run around the clock.

Solar thermal plants have been rolled out in a number of locations world-wide, but the uptake in Australia has been limited to two small plants: a 1.5 MW demonstration solar thermal plant has been added to the coal-fired Liddell Power station, and CSIRO has a 0.5 MW solar thermal power station in Mayfield. The biggest recent development was in June 2011, when a 250 MW solar thermal/gas hybrid plant (Solar Dawn) was given 464 million dollars of government funding as part of the Australian Government’s Solar Flagships program. Solar power is a natural fit to the Australian climate, so I’d expect some considerable growth in this sector. Until then, we’re left to wonder why Germany has invested more in solar infrastructure than Australia, when the majority of Australia has more sunshine hours per day than the German average.

Centenary of Mawson’s 1911 Antarctic Expedition – Part 2 – The riddle of the sledges

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Australian-made sledge used on the 1911-14 Mawson Expedition, Powerhouse Museum Collection, H8143, Gift of Australian Museum, 1967.

What do Douglas Mawson, aviation pioneer Lawrence Hargrave, a Sydney car body builder and the Klondike gold rush have in common? They are all part of the riddle of the Museum’s sledges.

In my last post I wrote about the Norwegian sledge in the Museum’s collection used on Mawson’s 1911-14 Australian Antarctic Expedition. According to Mawson’s “The Home of the Blizzard” he not only took 20 Norwegian-made sledges but 17 sledges made in Sydney. The Museum has 3 sledges used on this expedition, one has a manufacturer’s plate indicating it was made by L. Hargan of Norway but the other two are quite different in appearance.

During my research on the sledges I found the documentary evidence on the Australian-made sledges was patchy and inconclusive. Perhaps the sledges themselves could help explain their origins. Sue Gatenby, the Museum’s Conservation Scientist enlisted the help of botanical expert, John Ford, to analyse all the sledges in our collection. In fact we have six, three from Mawson’s expedition and another three said to be from Captain Robert Falcon Scott’s ill-fated 1912 expedition.

Botanist, John Ford, taking timber samples from the Museum’s sledges. Photo Powerhouse Museum Collection.

The botanical expert took very tiny samples for later analysis. He verified that Mawson’s Norwegian sledge was hickory, another was also hickory but the third was Corymbia (Eucalyptus) maculata or spotted gum, an Australian hardwood. But who on earth would have made a sledge of Australian gum trees? The very idea of making Antarctic sledges here in sunny Sydney seems as bizarre as an Icelandic manufacturer making surf boards or bikinis.

With his tiny torch, the botanist carefully examined the grain of the sledges. While running his eye along one of the cross pieces he asked “Does the name Worsfold mean anything to you?” Yes! I was so excited! By chance the week before one of our archivists, Jill Chapman, who knew I was researching the sledges, sent me a photocopy of a 1915 letter in the Museum’s Archives from one Alexander Worsfold, a car body builder of King Street, St Peters, an inner Western Sydney suburb. But I wondered at the time how did he fit in? (Trove wasn’t then online.) I should add that the sledges had all been out of the store and thoroughly cleaned and repaired in our conservation labs during the 1980s and photographed several times in the studio yet no-one had ever notice the name Worsfold impressed into the timber.

Alexander Worsfold’s letterhead advised that he was a “wholesale manufacturer of motor and carriage ware, especially wheels and bodies”. This was when motor car bodies were still hand-built of timber. His printed letterhead further confirmed his involvement in supplying several Antarctic explorers as it notes: “Specialities: Designer and Manufacturer of Sleighs, Skis, Toboggans and Antarctic Appliances for Dr Mawson’s Expedition, Captain Scott’s Relief, Professor David’s Magnetic Discovery”. Added in pen at the end of this list is: “Shackleton Expd 1914″.

In 1915 Worsfold had written to the Museum seeking support for his application to help the War effort as he had specific knowledge of Australian timbers. He enlisted in the AIF and went into the 9th Australian Field Ambulance where he designed a portable stretcher which looks remarkably like a sledge. Worsfold was also involved with Lawrence Hargave and his timber cellular box kites.

The timber for Worsfold’s sledges was supplied by Allen Taylor & Co. who had numerous timber mills all over New South Wales. They were also “powellised” or heated to rapidly season and preserve them. At this time there was great interest, and research undertaken, at the Museum regarding the commercial use of Australian timber. But who had knowledge in Sydney at the time to design sledges? It is said to have come from Alfred Charles Samuels who’d been at the Canadian 1896-1901 Klondike gold rush. His nickname was Klondike Dick and he ironically ended up being Mayor of the beachside suburb of Manly.

And how did Mawson find the Australian sledges in Antarctic? In “The Home of the Blizzard” he noted that the ones “built in Sydney, of Australian hard woods, included mountain ash which tended to split and spotted gum which was strong but heavy.” I can tell you that the runners on our Norwegian sledge are considerably worn but the Australian ones showed little wear.

This all goes to show that object research can be a work in progress. We add bits and gradually build up the story.

How do you bottle the wind?

Published by Debbie Rudder 0 Comments Tags: , , , .

Image: Powerhouse Museum

“The final perfection of the storage battery, which I believe has been accomplished, will in my opinion bring about a multitude of changes and improvements in our business and social economy.”
— Thomas Edison
North American Review, 1902

The Clean Energy Act recently passed into law. This carbon pricing legislation heralds a broad transformation in the electricity industry in Australia: increased investment in renewable energy will prompt a revision of our energy infrastructure, and a key focus of this restructuring will involve adding energy storage to the electrical grid.

Energy storage is exactly as the name implies: you take energy, usually electricity, and convert it to another form to save it for later use. The electronics industry has been revolutionised by innovations in energy storage: iPhones, portable GPS, and ultra-slim laptops would not exist without batteries that efficiently convert electricity into chemical energy, and back again. You might expect that the electrical grid, which brings power to homes and industry, has been similarly transformed by these innovations in energy storage. The reality is a very different matter. Bill Gates wonderfully summarised this in a 2010 talk: if we connected all the batteries in the world, including all batteries from the consumer electronic devices I mentioned above, this monumental collection of batteries would be able to store — wait for it — ten minutes of the world’s energy demands.

Given the ubiquity of batteries in our everyday lives, it may seem odd that we do so little grid-scale energy storage. The reason for this is historical: the technology for generating energy outpaced the technology for storing it efficiently. As a result, today’s electricity grid is the ultimate ‘just in time’ system: electricity supply is generated to match demand, as perfectly as possible, as demand varies across each day and season. To facilitate this, some power stations (coal or nuclear) generate continuously 365 days a year, while others switch on and off as demand fluctuates (natural gas or hydroelectric power stations). 

As we transition to renewable forms of power generation — e.g. solar and wind — the design of our electricity grid hits a roadblock, because most renewable power plants are intermittent generators. The sun doesn’t shine all the time, and the wind doesn’t blow all the time; and the times when these renewable plants are generating lots of electricity might not correspond to times when we, the electricity-consuming public, are demanding more power. As a result, renewable power plants can’t be on all the time (and compete with coal power) and can’t be switched on and off at will (and compete with demand-following power plants like natural gas). This limits the market uptake of renewable power technologies, and makes the energy they generate more expensive than energy from other sources.

The answer to both these problems? Energy storage. First and most obviously, storing energy when it is in surplus lets renewable power plants deliver power to consumers when the sun isn’t shining and the wind isn’t blowing. With energy storage, renewable power plants can compete with continuously operating power stations like coal power plants. Secondly, integrating energy storage into renewable power stations allows the owners of these plants to engage in arbitrage: producing energy when a station can generate it most cheaply, and selling it at a premium when customers demand it. With energy storage, renewable power plants can also compete effectively with demand-following plants like natural gas power plants.

Improving competitiveness in both these ways will mean that renewable power plants are a more attractive investment, and it will drive down the cost of the energy they produce. This is a good thing for both the environment and your wallet.

There are many more benefits to grid-scale energy storage, but I hope I’ve sold you on at least two reasons why storing electricity is a good idea. (Those interested in other applications of grid-scale energy storage should see Appendix C of this 2002 Sandia report — be forewarned that it’s a little dry and technical). In the coming weeks, I’ll be writing a number of blog posts about various forms of energy storage that we might see commercialised within the next ten years. Batteries are just the starting point: ultracapacitors, flywheels, molten metal, compressed air, and even hydrogen are all forms of grid-scale energy storage that are being considered by utility companies worldwide. Bottling the wind will soon be something that we rely on every day.

This piece was written by Brett Szmajda, intern at the Powerhouse Museum.