The first robot that mimics the water striders’ jumping abilities

Engineerblogger

Aug 3, 2012

Credit: American Chemical Society

The first bio-inspired microrobot capable of not just walking on water like the water strider – but continuously jumping up and down like a real water strider – now is a reality. Scientists reported development of the agile microrobot, which could use its jumping ability to avoid obstacles on reconnaissance or other missions, in ACS Applied Materials & Interfaces.

Qinmin Pan and colleagues explain that scientists have reported a number of advances toward tiny robots that can walk on water. Such robots could skim across lakes and other bodies of water to monitor water quality or act as tiny spies. However, even the most advanced designs – including one from Pan’s team last year – can only walk on water. Pan notes that real water striders actually leap. Making a jumping robot is difficult because the downward force needed to propel it into the air usually pushes the legs through the water’s surface. Pan’s group looked for novel mechanisms and materials to build a true water-striding robot.

Using porous, super water-repellant nickel foam to fabricate the three supporting and two jumping legs, the group made a robot that could leap more than 5.5 inches, despite weighing as much as 1,100 water striders. In experiments, the robot could jump nearly 14 inches forward – more than twice its own length – leaving the water at about 3.6 miles per hour. The authors report that the ability to leap will make the bio-inspired microrobot more agile and better able to avoid obstacles it encounters on the water’s surface.

The authors acknowledge funding from the State Key Laboratory of Robotics and System of Harbin Institute of Technology and the National Natural Science Foundation of China.

Source:  American Chemical Society

Additional Information:

• Why Superhydrophobicity Is Crucial for a Water−Jumping Microrobot? Experimental and Theoretical Investigations”

Engineers Devise New Way to Split Water: Nontoxic, noncorrosive, "low-temperature" method makes use of wasted heat

Engineerblogger
June 11, 2012

Providing a possible new route to hydrogen-gas production, researchers at the California Institute of Technology (Caltech) have devised a series of chemical reactions that allows them, for the first time, to split water in a nontoxic, noncorrosive way, at relatively low temperatures.

A research group led by Mark Davis, the Warren and Katharine Schlinger Professor of Chemical Engineering at Caltech, describes the new, four-reaction process in the early edition of the Proceedings of the National Academy of Sciences (PNAS).

Hydrogen is a coveted gas: industry uses it for everything from removing sulfur from crude oil to manufacturing vitamins. Since its combustion does not emit carbon dioxide into the atmosphere, there is some belief that it could even fuel a potential "hydrogen economy"—an energy-delivery system based entirely on this one gas. But since there is no abundant supply of hydrogen gas that can be simply tapped into, this lighter-than-air gas has to be mass-produced.

One way to make hydrogen is by using heat to split water, yielding pure hydrogen and oxygen. Known as thermochemical water splitting, this method is appealing because it can take advantage of excess heat given off by other processes. Thus far, it has been attempted in two ways: using two steps and taking advantage of high temperatures (above 1000°C) associated with solar collectors; or through multiple steps at "lower temperatures"—those below 1000°C—where, for example, the excess heat from nuclear reactors could drive the chemistry.

Davis is interested in this latter approach, which actually takes him back to his academic roots: his first paper as a graduate student dealt with a low-temperature water-splitting cycle, called the sulfur-iodine system, which has since been piloted for use around the world. Although that cycle operates at a maximum temperature of 850°C, it also produces a number of toxic and corrosive liquid intermediates that have to be dealt with. The cycle's high-temperature counterparts typically involve simpler reactions and solid intermediates—but there are very few processes that produce excess heat at such high temperatures.

"We wanted to combine the best of both worlds," Davis says. "We wanted to use solids, as they do in the high-temperature cycles, so we could avoid these toxicity and corrosion issues. But we also wanted to learn how to lower the temperature."

The first thing postdoctoral scholar and lead author Bingjun Xu and graduate student Yashodhan Bhawe did was to prove via thermodynamic arguments that a two-step, low-temperature cycle for water splitting will not be practical. "Nature's telling you 'No way,'" Davis says. "It was really a key point that told us we had to go away from looking for a two-step process, and that guidance directed us down another pathway that turned out to be quite fruitful."

The four-reaction cycle the team came up with begins with a manganese oxide and sodium carbonate, and is a completely closed system: the water that enters the system in the second step comes out completely converted into hydrogen and oxygen during each cycle. That's important because it means that none of the hydrogen or oxygen is lost, and the cycle can run over and over, splitting water into the two gases. In the current paper, the researchers ran their newly created cycle five times to show reproducibility. It will be needed to show that the cycle can run thousands of times in order to be practical. Experiments of this type are beyond the capabilities currently in the Davis lab.

"We're excited about this new cycle because the chemistry works, and it allows you to do real thermochemical water splitting with temperatures of 850°C without producing any of the halides or other types of corrosive acids that have been problems in the past," Davis says. Still, he is careful to point out that the implementation of the cycle as a functioning water-splitting system will require clever engineering. For example, for practical purposes, engineers will want some of the reactions to go faster, and they would also need to build processing reactors that have efficient-energy flows and recycling amongst the different stages of the cycle.

Going forward, the team plans to study further the chemistry of the cycle at the molecular level. They have already learned that shuttling sodium in and out of the manganese oxide is critical in lowering the operating temperature, but they want to know more about what exactly is happening during those steps. They hope that the enhanced understanding will allow them to devise cycles that could operate at even lower maximum temperatures.

Figuring out ways to decrease the operating temperatures is at the heart of Davis's interest in this project. "What we're trying to ask is, 'Where are the places around the world where people are just throwing away energy in the form of heat?'" he says. He speculates that there could be a day when water-splitting plants are able to run on the heat given off by a variety of manufacturing industries such as the steel- and aluminum-making industries and the petrochemicals industries, and by the more traditional power-generation industries. "The lower the temperature that we can use for driving these types of water-splitting processes," he says, "the more we can make use of energy that people are currently just wasting."

 Source: Caltech

•  The PNAS paper, "Low-temperature, manganese oxide-based thermochemical water splitting cycle" is now online. The work was funded by a donation from Mr. and Mrs. Lewis W. van Amerongen.

Photovoltaic Cells Tap Underwater Solar Energy

Engineerblogger
June 8, 2012

Power density of GaInP and crystalline silicon cells, underwater, as a function of depth. (U.S. Naval Research Laboratory) 

Scientists at the U.S. Naval Research Laboratory, Electronics Science and Technology Division, dive into underwater photovoltaic research to develop high bandgap solar cells capable of producing sufficient power to operate electronic sensor systems at depths of 9 meters.

Underwater autonomous systems and sensor platforms are severely limited by the lack of long endurance power sources. To date, these systems must rely on on-shore power, batteries or solar power supplied by an above water platform. Attempts to use photovoltaics have had limited success, primarily due to the lack of penetrating sunlight and the use of solar cells optimized more towards the unimpeded terrestrial solar spectrum.

"The use of autonomous systems to provide situational awareness and long-term environment monitoring underwater is increasing," said Phillip Jenkins, head, NRL Imagers and Detectors Section. "Although water absorbs sunlight, the technical challenge is to develop a solar cell that can efficiently convert these underwater photons to electricity."

Even though the absolute intensity of solar radiation is lower underwater, the spectral content is narrow and thus lends itself to high conversion efficiency if the solar cell is well matched to the wavelength range. Previous attempts to operate solar cells underwater have focused on crystalline silicon solar cells and more recently, amorphous silicon cells.

High-quality gallium indium phosphide (GaInP) cells are well suited for underwater operation. GaInP cells have high quantum efficiency in wavelengths between 400 and 700 nanometers (visible light) and intrinsically low dark current, which is critical for high efficiency in lowlight conditions.

The filtered spectrum of the sun underwater is biased toward the blue/green portion of the spectrum and thus higher bandgap cells such as GaInP perform much better than conventional silicon cells, states Jenkins.

Preliminary results at a maximum depth of 9.1 meters reveal output to be 7 watts per square meter of solar cells, sufficient to demonstrate there is useful solar power to be harvested at depths commonly found in nearshore littoral zones.

Source: U.S. Naval Research Laboratory

Nanosheet Catalyst Discovered to Sustainably Split Hydrogen from Water

Engineerblogger
May 10, 2012

This magnified image from a transmission electron microscope reveals details of the unexpected nanosheet structure of the nickel-molybdenum-nitride catalyst, seen here as dark, straight lines.

Hydrogen gas offers one of the most promising sustainable energy alternatives to limited fossil fuels. But traditional methods of producing pure hydrogen face significant challenges in unlocking its full potential, either by releasing harmful carbon dioxide into the atmosphere or requiring rare and expensive chemical elements such as platinum.

Now, scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have developed a new electrocatalyst that addresses one of these problems by generating hydrogen gas from water cleanly and with much more affordable materials. The novel form of catalytic nickel-molybdenum-nitride – described in a paper published online May 8, 2012 in the journal Angewandte Chemie International Edition – surprised scientists with its high-performing nanosheet structure, introducing a new model for effective hydrogen catalysis.

“We wanted to design an optimal catalyst with high activity and low costs that could generate hydrogen as a high-density, clean energy source,” said Brookhaven Lab chemist Kotaro Sasaki, who first conceived the idea for this research. “We discovered this exciting compound that actually outperformed our expectations.”

Goldilocks chemistry

Water provides an ideal source of pure hydrogen – abundant and free of harmful greenhouse gas byproducts. The electrolysis of water, or splitting water (H2O) into oxygen (O2) and hydrogen (H2), requires external electricity and an efficient catalyst to break chemical bonds while shifting around protons and electrons. To justify the effort, the amount of energy put into the reaction must be as small as possible while still exceeding the minimum required by thermodynamics, a figure associated with what is called overpotential.

For a catalyst to facilitate an efficient reaction, it must combine high durability, high catalytic activity, and high surface area. The strength of an element’s bond to hydrogen determines its reaction level – too weak, and there’s no activity; too strong, and the initial activity poisons the catalyst.

“We needed to create high, stable activity by combining one non-noble element that binds hydrogen too weakly with another that binds too strongly,” said James Muckerman, the senior chemist who led the project. “The result becomes this well-balanced Goldilocks compound – just right.”

Unfortunately, the strongest traditional candidate for an electrocatlytic Goldilocks comes with a prohibitive price tag.

Problems with platinum

Platinum is the gold standard for electrocatalysis, combining low overpotential with high activity for the chemical reactions in water-splitting. But with rapidly rising costs – already hovering around $50,000 per kilogram – platinum and other noble metals discourage widespread investment.

“People love platinum, but the limited global supply not only drives up price, but casts doubts on its long-term viability,” Muckerman said. “There may not be enough of it to support a global hydrogen economy.”

In contrast, the principal metals in the new compound developed by the Brookhaven team are both abundant and cheap: $20 per kilogram for nickel and $32 per kilogram for molybdenum. Combined, that’s 1000 times less expensive than platinum. But with energy sources, performance is often a more important consideration than price.

Turning nickel into platinum

In this new catalyst, nickel takes the reactive place of platinum, but it lacks a comparable electron density. The scientists needed to identify complementary elements to make nickel a viable substitute, and they introduced metallic molybdenum to enhance its reactivity. While effective, it still couldn’t match the performance levels of platinum.

“We needed to introduce another element to alter the electronic states of the nickel-molybdenum, and we knew that nitrogen had been used for bulk materials, or objects larger than one micrometer,” said research associate Wei-Fu Chen, the paper’s lead author. “But this was difficult for nanoscale materials, with dimensions measuring billionths of a meter.”

The scientists expected the applied nitrogen to modify the structure of the nickel-molybdenum, producing discrete, sphere-like nanoparticles. But they discovered something else.

Subjecting the compound to a high-temperature ammonia environment infused the nickel-molybdenum with nitrogen, but it also transformed the particles into unexpected two-dimensional nanosheets. The nanosheet structures offer highly accessible reactive sites – consider the surface area difference between bed sheets laid out flat and those crumpled up into balls – and therefore more reaction potential.

Using a high-resolution transmission microscope in Brookhaven Lab’s Condensed Matter Physics and Materials Science Department, as well as x-ray probes at the National Synchrotron Light Source, the scientists determined the material’s 2D structure and probed its local electronic configurations.

“Despite the fact that metal nitrides have been extensively used, this is the first example of one forming a nanosheet,” Chen said. “Nitrogen made a huge difference – it expanded the lattice of nickel-molybdenum, increased its electron density, made an electronic structure approaching that of noble metals, and prevented corrosion.”

Hydrogen future

The new catalyst performs nearly as well as platinum, achieving electrocatalytic activity and stability unmatched by any other non-noble metal compounds. “The production process is both simple and scalable,” Muckerman said, “making nickel-molybdenum-nitride appropriate for wide industrial applications.”

While this catalyst does not represent a complete solution to the challenge of creating affordable hydrogen gas, it does offer a major reduction in the cost of essential equipment. The team emphasized that the breakthrough emerged through fundamental exploration, which allowed for the surprising discovery of the nanosheet structure.

“Brookhaven Lab has a very active fuel cell and electrocatalysis group,” Muckerman said. “We needed to figure out fundamental approaches that could potentially be game-changing, and that’s the spirit in which we’re doing this work. It’s about coming up with a new paradigm that will guide future research.”

Additional collaborators on this research were: Anatoly Frenkel of Yeshiva University, Nebojsa Marinkovic of the University of Delaware, and Chao Ma, Yimei Zhu and Radoslav Adzic of Brookhaven Lab.

The research was funded by Brookhaven's Laboratory Directed Research and Development (LDRD) Program. The National Sychrotron Light Source and other Brookhaven user facilities are supported by the DOE Office of Science.

Source: Brookhaven National Laboratory

Additional Information:

• Scientific Paper: “Hydrogen-Evolution Catalysts Based on Non-Nobel Metal Nickel–Molybdenum Nitride Nanosheets”

Bioalchemy: turning sludge into clear water

Engineerblogger
May 3, 2012

Credit: Youris.com

Biological treatment plus ozone can reduce the amount of sludge coming from wastewater treatment plants by a factor of ten.

The process was developed by the Water Research Institute (WRI) of the Italian National Research Council and tested and scaled-up as part the EU-funded Innowatech project

We know that biological processes offer the cheapest way to treat industrial wastewater. But pollutants from industries such as leather, textiles and pharmaceuticals are not easily broken down by microbes.

WRI scientists have developed an innovative technology where the microbial biomass, which breaks down wastes, grows mainly as granules; the process is known as SBBGR (Sequencing Batch Biofilter Granular Reactor). The granules are trapped in pores between plastic-support material in a reactor and the microbes are stressed so less sludge is produced. This is because the microbes are not given suitable conditions to proliferate, so fewer microbes and less waste results.

Removing one kilo of wastewater through a biological system, produces half a kilo of sludge, which then needs to be disposed of, according to Antonio Lopez, project coordinator at WRI. “With this technology, you produce only 50 grams of sludge.” A treatment plant using this technology could be ten times smaller than usual.

But there can be complicating factors such as what goes into the reactor and biomass concentration, comments Christoph Brepols, wastewater expert at Erftverband, the Erft river water association, in Germany. If the sludge production is decreased by ten times, he believes, this would not necessarily mean that the bioreactor volume can be decreased by the same ratio.

Integrating ozone with the reactor allows effluents from leather and textile processing to be treated. Ozone is a costly but powerful oxidiser and can break down most organic compounds. In the new system, ozone does not completely break down the pollutants but transforms them into more biodegradable compounds. This means less ozone is needed, reducing treatment costs.

“Tannery wastewater is a sort of benchmark in the sector of industrial wastewater,” says Lopez, because its composition is complex and difficult to treat. At a pilot scale facility for treating tannery wastewater, the final effluent from the process looked like tap water, the WRI researchers reported. In Italy alone, leather processing has a turnover of around €5 billion, around 1,500 firms are involved, and about 20,000 workers employed.

Mark van Loosdrecht, environmental biotechnologist at Delft University of Technology, expressed concerns about the use of ozone. Using ozone is technically feasible, but it increases energy usage and treatment costs, so the net benefit for ecosystems is not very clear.

Granular sludge reactors will find their niche, along with other technologies, as there is no “one size fits all” solution to wastewater treatment, noted Brepols.

Sludge output in Europe is on the rise; 5.5 million tonnes of dry solids came from plants in 1992, increasing to 10 million by 2007. It’s expensive business. Each tonne of dry solids costs between 350 and 750 euros to dispose of, so new technology is vital.

Source: Youris.com (European Research Media Center)

Wind Turbine Makes 1,000 Liters of Clean Water a Day in the Desert

Engineerblogger
April 19, 2012

Credit: Eole Water

A cool new concept being tested in the Abu Dhabi desert uses a wind turbine to condense water from the air and pump it into storage tanks for filtration and purification. The technology was created by Eole Water after its founder, Marc Parent, was inspired by the water he could collect from his air conditioner unit while living in the Caribbean. He began thinking of ways that water could be condensed from air in areas without access to grid power and the wind turbine concept was born.

The 30-kW wind turbine houses and powers the whole system. Air is taken in through vents in the nose cone of the turbine and then heated by a generator to make steam. The steam goes through a cooling compressor that creates moisture which is then condensed and collected. The water produced is sent through pipes down to stainless steel storage tanks where it's filtered and purified.

Credit: Eole Water

A prototype of the technology has been installed in Abu Dhabi since October and has been capable of producing 500 to 800 liters of clean water a day from the dry desert air. Eole Water says that volume can increase to 1,000 liters a day with a tower-top system. The system requires wind speeds of 15 miles per hour or higher to produce water.

This technology uses a simple process that has been experimented with in a variety of designs, but this is the first powered by a wind turbine. That component makes it able to produce large quantities of clean water in areas that don't have ready access to it without requiring grid power, which makes it especially promising for remote communities and disaster areas. Eole has already landed 12 industrial partners for manufacturing the turbines.

Source: Treehugger

Additional Information:

• To read more about Eole Water.

Use less water, producing energy and fertilizer at the same time

Engineerblogger
April 18, 2012

At the decentralized urban infrastructure system DEUS 21, the developers contemplate water as a raw material, from the tap to the clarification plant. © Fraunhofer

Water is a valuable resource. New technologies are making it easier to handle drinking water responsibly, purify wastewater effectively and even recover biogas and fertilizer. Fraunhofer researchers will be showing how this is done at the Hannover Fair (23 - 27 April) in the House of Sustainability.

Clean drinking water and basic sanitation are human rights. Yet almost 780 million of the world‘s population still have no access to drinking water and some 2.6 billion people live without sanitary facilities. Water, though, is also an important economic factor: Today, agricultural and manufacturing businesses already use up more than four fifths of this precious commodity. And the demand for water continues to rise. The Organization for Economic Cooperation and Development (OECD) is expecting that by 2050, global water consumption will have risen by more than half. Some 40 percent of the world‘s population will then be living in regions with extreme water shortages - 2.3 billion people more than today.

We have, to date, been wasteful in our use of this valuable resource. In Germany, each and every individual consumes around 120 liters of water per day - they drink only three. Another third is flushed down the toilet. But in some regions of the world, clean water is much too precious to be wasted transporting excrement. New technologies are allowing us to significantly reduce drinking water consumption, purify wastewater effectively and even recover biogas and fertilizer. The researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB and System and Innovation Research ISI have developed the solutions as part of the DEUS „Decentral Urban Water Infrastructure Systems“ project.

Treatment of rainwater
Not all water has to be drinking quality - for watering the garden or flushing the toilet, for instance. Using rainwater and treated wash water for personal needs pays off, especially in arid regions. Fraunhofer researchers have developed a modern water treatment plant for this very purpose. It produces germ-free, usable water that satisfies the requirements of the German Drinking Water Regulation (TVO). „The treated rainwater can be used for showering, washing, flushing the toilet and watering the garden“, explains Dr. Dieter Bryniok from the IGB in Stuttgart.

Vacuum sewage systems reduce water consumption
Vacuum sewage is a key building block. The concept drastically reduces water consumption. Vacuum toilets need only about 0.5 to 1 liter of water per flush. By comparison: Conventional toilets use between four and eight liters.

What‘s more, the investment and maintenance costs are lower than those for conventional sewage systems. Domestic wastewater is biologically purified in an anaerobic, high-performance membrane plant. The heart of the system, fully-mixed anaerobic bioreactors, treat the wastewater without aeration or oxygen and the organic constituents are converted into biogas, a mixture of methane and carbon dioxide.

The bioreactors are combined with rotation disk filters. The wastewater is forced through ceramic filter disks. The rotational movement of the ceramic membranes inhibits the formation of covering layers. So the filtration capacity is maintained over a prolonged period. The purified water drains into the filter plant‘s hollow shaft. The pores in the membrane range in size from 60 nanometers and 0.2 micrometers. All larger particles are routed into the bioreactors. Bacteria are also returned to the reactors, which breakdown the organic waste that has been filtered out. The recovered biogas provides power and heat. The entire plant works in the absence of air. The benefit: there‘s no bad odor.

Recovery of biogas and fertilizer
Another special feature of the disposal concept: As well as domestic wastewater, the wastewater purification plant can also process bio kitchen waste. Kitchens are simply equipped with a waste macerator, accommodated below the sink. The system is connected to the domestic wastewater pipes. As more and more organic waste gets into the wastewater, the biogas yield increases. Bio-waste and wastewater produce another by-product: fertilizer. Nitrogen and phosphorous are converted into ammonium and phosphorous salts and can be recovered through the applied membrane technology.

As Bryniok explains, „The water management concept DEUS 21 benefits mainly those regions that still have no water infrastructure with sewage system and central clarification plant, or in which the old infrastructure can no longer be modified to meet the new challenges posed by climate change or de-population.“ „The system is also ideally suited for export to water-scarce areas, because it can be adapted specifically to the needs of dry and semi-arid regions.“

The latest China project
Fraunhofer researchers involved in the Advanced wastewater treatment in Guangzhou“ project are currently working towards optimizing the DEUS technology in an industrial park in the City of Guangzhou, Guangdong Province to suit the conditions in China.

Source: Fraunhofer-Gesellschaft

Additional Information:

• To read about DEUS 21: DEcentralised Urban infrastructure System

Osmotic power generation: Creating the next generation power stations

Engineerblogger
April 10, 2012

In pressure-retarded osmosis, seawater and fresh water are separated by a semi-permeable membrane which allows the passage of water but prevents that of salt ions. (Photo: Morguefile)

New membrane technology and long-term trials will bring another source of renewable energy one step closer to viability.

Osmotic power generation is a renewable energy source which results in no pollution of the atmosphere and only moderate emissions to the sea.

Globally, the energy generating potential of osmotic generation is estimated at around 1,650 TWh, which corresponds to around 12 times Norway’s annual energy production.

“The energy source is also predictable, compared with wind, wave, tidal and solar generation,” says Edvard Sivertsen, project manager in SINTEF Building and Infrastructure.

He and his colleagues will now collaborate with Statkraft and a number of membrane manufacturers to test and optimise the membranes which form the basis of the technology.

Fresh and salt water mixed

The principle of osmotic power generation is the release of so-called “mixing energy” when fresh water is mixed with salt water. An osmotic generating station uses a semi-permeable membrane to extract this energy.

Sivertsen explains that when fresh water is mixed with salt water, energy is released. To make use of that energy, seawater and fresh water must meet on either side of a membrane and the pressure on the seawater side must be higher.

Fresh water will then permeate through the membrane to the seawater side, resulting in an increase in pressure on this side of the membrane. The increased water pressure is used to drive a turbine and generate electrical energy.

“The challenge is getting the membrane to allow the passage of water while keeping salt out. In other words, a good membrane will have ‘conflicting’ properties,” says Sivertsen.

Other challenges will be to create a membrane which is both effective enough and durable enough to tolerate operation over a long period.

This is no simple task: an osmotic power station corresponding to a moderate-sized hydroelectric plant will need membranes which are many times larger than the largest desalination installations so far constructed.

Compact solution

Sivertsen says to achieve the required energy efficiency, as much as five million square metres of membrane will be needed to operate an osmotic generating plant with a production output of 25 MW.

He points out that this will be achieved by packing membranes in special modules, with each cubic metre of module containing up to 1000 square metres of membrane. This makes it possible to construct compact generating plants which make efficient use of area.

Hunting for the right properties

The researchers are now working on investigating the characteristics of membranes to determine their technical performance.

Sivertsen says the membranes are around a tenth of a millimetre thick and consist principally of two layers.

One layer has the separating characteristics which enable water to pass through, while salt does not. The other layer acts as a supporting structure for the separating membrane.

The SINTEF research has demonstrated that the supporting structure of a membrane has more influence on the efficiency of the membrane than initially assumed.

“We have a laboratory which was constructed for the purpose of testing membranes,” says Sivertsen. “We have also developed modelling applications which describe the transport of water and salt through a membrane.”

The combination of experimental testing and modelling of the results provides valuable knowledge of the properties of the various membranes.

However, it isn’t only the membrane that affects the energy production of an osmotic power station: among other things, organic material in the water used in the plant may also cause problems.

Water in rivers and lakes contains both dissolved substances and particulate matter which can cause fouling of the membrane.

“One of the main activities in this project will be to carry out testing both in the field and under controlled conditions in the laboratory,” explains Sivertsen.

This will provide knowledge of the effect such contamination has on the efficiency of the membrane over a period of time.

Old idea

The idea of osmotic power generation arose around 1950, and about 20 years later a number of theories were published regarding the energy generation potential of the method.

This attracted the interest of two SINTEF research scientists, Thorleif Holt and Thor Thorsen, who began looking into the concept in the early 1980s and who have since been working to create a viable method of producing renewable energy based on osmosis.

“The first research project began at SINTEF in 1997,” says Geir Brekke, technical manager for osmotic power generation in Statkraft.

Since then activities have carried on continuously in the field of osmotic power generation and SINTEF currently has world-leading expertise in this field.

Recognition of expertise

During the last five years, the number of research establishments studying membrane applications using osmosis and pressure-retarded osmosis has increased significantly worldwide.

The new project has a budget of €1.5 million and will be financed by Statkraft and the Research Council of Norway’s RENERGI programme.

Source: ScienceNordic

Jellyfish inspires latest ocean-powered robot

Engineerblogger
March 21, 2012

American researchers have created a robotic jellyfish, named Robojelly, which not only exhibits characteristics ideal to use in underwater search and rescue operations, but could, theoretically at least, never run out of energy thanks to it being fuelled by hydrogen.

Constructed from a set of smart materials, which have the ability to change shape or size as a result of a stimulus, and carbon nanotubes, Robojelly is able to mimic the natural movements of a jellyfish when placed in a water tank and is powered by chemical reactions taking place on its surface.

“To our knowledge, this is the first successful powering of an underwater robot using external hydrogen as a fuel source,” said lead author of the study Yonas Tadesse.

The creators of Robojelly, from Virginia Tech, have presented their results today, 21 March, in IOP Publishing’s journal Smart Materials and Structures.

The jellyfish is an ideal invertebrate to base the vehicle on due to its simple swimming action: it has two prominent mechanisms known as “rowing” and “jetting”.

A jellyfish’s movement is down to circular muscles located on the inside of the bell – the main part of the body shaped like the top of an umbrella. As the muscles contract, the bell closes in on itself and ejects water to propel the jellyfish forward. After contracting, the bell relaxes and regains its original shape.

This was replicated in the vehicle using commercially-available shape memory alloys (SMA) – smart materials that “remember” their original shape – wrapped in carbon nanotubes and coated with a platinum black powder.

The robot is powered by heat-producing chemical reactions between the oxygen and hydrogen in water and the platinum on its surface. The heat given off by these reactions is transferred to the artificial muscles of the robot, causing them to transform into different shapes.

This green, renewable element means Robojelly can regenerate fuel from its natural surroundings and therefore doesn’t require an external power source or the constant replacement of batteries.

At the moment, the hydrogen-powered Robojelly has been functioning whilst being clamped down in a water tank. The researchers admit that the robot still needs development to achieve full functionality and efficiency; however, the potential can be seen in the video below where the robot is powered by electricity.

“The current design allows the jellyfish to flex its eight bell segments, each operated by a fuel-powered SMA module. This should be sufficient for the jellyfish to lift itself up if all the bell segments are actuated.

“We are now researching new ways to deliver the fuel into each segment so that each one can be controlled individually. This should allow the robot to be controlled and moved in different directions,” Tadesse continued.

This study is part of the MURI program sponsored by Office of Naval Research.




Source: IOP Institute of Physics

NRL Tests Robotic Fueling of Unmanned Surface Vessels

Engineerblogger
March 21, 2012

Positioned alongside a stationary platform, under simulated sea conditions, the USV Sea Fox receives fuel from a robotic fluids transfer arm via magnetic refueling fitting (shown here mounted in the forward bow section of the vessel). Photo: U.S. Naval Research Laboratory

Engineers from the NRL Spacecraft Engineering Department (SED) successfully demonstrate the robotic fluids transfer from a stationary platform to an Unmanned Surface Vehicle (USV) in wave heights greater than three feet. The Rapid Autonomous Fuel Transfer (RAFT) project exhibits the ability to track the motion of a Sea Fox naval vessel, safely emplace a magnetic refueling fitting to an on-board refueling receptacle and successfully complete fluids transfer.

Under current circumstance, USV refueling demands that a grappled connection, usually by hand, be made between the USV and the refueling vessel.

"Refueling a USV at sea, particularly in adverse weather or in high sea states, can prove difficult and often dangerous," said Dr. Glen Henshaw, Attitude Control Section, SED Control Systems Branch. "Transferring our extensive knowledge and proven success of robotic spacecraft servicing can prove equally successful in reducing risks at sea."

Providing the host ship the capability to refuel USVs without the need to bring them aboard ship enhances mission efficiency and reduces host ship exposure. This works to improve the effectiveness of naval USV missions and decrease risks to personnel and potential damage to vessels and equipment.

Experimenting with both fully autonomous and human-controlled operations at the U.S. Army Aberdeen Test Center wave simulator facility, NRL engineers completed approximately 60 trial refueling attempts at sea states ranging from zero, or calm seas, to 3.25, or maximum wave heights in excess of three feet, with a demonstrated high rate of success.

Funded by the Defense Advanced Research Projects Agency (DARPA), the Rapid Autonomous Fuel Transfer (RAFT) project teamed NRL with Clemson University, Science Applications International Corporation (SAIC) and Space and Naval Warfare Systems Command (SPAWAR). NRL was the lead robotics integrator and designed the robotics system.

Further robotic transfer tests will possibly include land-based autonomous HMMV (High-Mobility Multipurpose Wheeled Vehicle) applications without the need to stop driving and on-air Unmanned Aerial Vehicle (UAV) refueling.

The USV Sea Fox was developed for Navy missions to provide force protection with more flexibility in Enhanced Maritime Interdiction Operations and safer Intelligence, Surveillance and Reconnaissance (ISR) gathering to aid in threat assessment, decision-making, and situational awareness, prior to escalation to lethal actions.

The U.S. Naval Research Laboratory's Spacecraft Engineering Department (SED) serves as the focal point for the Navy's in-house spacecraft bus capability. Research and development activities range from concept and feasibility studies through initial on orbit space systems operation. SED's Robotics Engineering and Control Laboratory serves as a national test bed to support research in the emerging field of space robotics including autonomous rendezvous and capture, remote assembly operations, and machine learning.

Source: U.S. Naval Research Laboratory

Engineer Launches Robotic Planetary Lake Lander

Engineerblogger
March 20, 2012

The lake lander TEX II is the latest component of Wolfgang Fink's autonomous planetary exploration fleet.

Wolfgang Fink of the University of Arizona department of electrical and computer engineering has developed an autonomous robotic lake lander that could be used to explore this planet and others.

Fink unveiled the lake lander, named Tucson Explorer II, or TEX II, in a paper titled "Robotic Lake Lander Test Bed for Autonomous Surface and Subsurface Exploration of Titan Lakes," which he presented March 8 at an aerospace conference organized by the Institute of Electrical and Electronics Engineers in Big Sky, Mont.

Fink presented TEX II as an autonomous exploration vehicle that potentially could be used to explore the lakes of liquid hydrocarbon known to exist on Saturn's largest moon, Titan.

TEX II is the second vehicle designed by Fink as part of his NASA-award-winning concept of future planetary exploration, which he calls "tier-scalable reconnaissance." The first vehicle was a land-based planetary rover(video below).

Fink envisions future planetary research being conducted by a hierarchy of intelligent, autonomous robots that could include satellites, airships or blimps, and a fleet of rovers and lake landers.

His humans-excluded vision is that an orbiting satellite would direct atmospheric blimps to scan potentially interesting areas of a planetary surface. The blimps would then order surface-based rovers and lake landers to investigate geological features in detail and collect samples in situ.

Fink's aim is to endow robots with curiosity. He wants them to want to investigate certain situations and environments, and then learn from those investigations so they can make increasingly smarter choices about where to go and what to investigate next.

A mission to Titan is many years away, but Fink made it clear that TEX II is close to being ready for more earthly duties. Like his planetary rovers, in its current configuration TEX II can be controlled from anywhere in the world via an Internet connection, and will soon be fully autonomous.

"TEX II is ready to deploy on missions related to defense and security, such as harbor surveillance and cleanup operations of littoral munitions dumps and mines," Fink said. It is also ideal for search and rescue operations in oceans, lakes, and hazardous environments, as well as for environmental research projects, he added.

For example, Tokyo Electric Power acknowledges that cleanup at the Fukushima Daiichi nuclear plant could take 40 years. The sea around the plant is known to contain radioactive elements, and the necessary extensive sampling and monitoring could be achieved more safely and thoroughly with a fleet of autonomous vehicles such as TEX II.

"Another potential application of this lander is oceanographic research into currents and marine pollution," Fink said.

Millions of tons of plastic and other debris are dumped into our oceans every year, and rotating ocean currents known as gyres accumulate this refuse at their center. Dumped plastics can act as a chemical sponge by absorbing and concentrating pollutants, which are ingested by animals and birds and introduced into the food chain.

These accumulations of debris are often referred to as "garbage patches," and a huge amount of oceanographic research remains to determine their size and toxicity, and how big an environmental, indeed existential, threat they pose.

"TEX II is currently fitted with onboard cameras and sonar that can penetrate up to 100 meters," Fink said. Other sensors could be added, he said, to detect pathogens, toxins, explosives, radiation, and so on.

TEX II is highly modular and portable and was designed as a catamaran for enhanced stability and to allow the various onboard sensors easy access to the surface and subsurface of the water, or other liquid, upon which it is deployed. It weighs about 100 pounds and its central raised deck can carry a 150-pound payload of computers, batteries and sensors. The twin hulls are each 6 feet long and set about 5 feet apart.

Air-propellers mounted at the back of each hull are powered by electric motors that can switch rotational direction to drive TEX II backward or forward, which makes the craft highly agile and maneuverable: For example, TEX II can pivot in position, which no single-engine water craft can do.

The propellers are set as far apart as possible so they deliver maximum torque to the chassis during turning. "Top speed depends on the size of the motors attached," Fink said. "But the important point is that sonar works best at speeds up to 5 knots."

The shallow draft of the fortified Styrofoam hulls decreases perturbation in the water around TEX II, which minimizes interference with subsurface telemetry from the onboard sensors. The entire chassis and sensor deck can be decoupled from the catamaran hulls and attached to an alternative propulsion system.

The Styrofoam hulls of TEX II have a significant advantage over other hull types – inflatable hulls, for example – in that they can sustain hull damage without jeopardizing buoyancy.

Fink is an associate professor in the UA department of electrical and computer engineering and the department of biomedical engineering. He holds the Edward and Maria Keonjian Endowed Chair in the UA College of Engineering, and directs the Visual and Autonomous Exploration Systems Research Laboratory.

Fink is a fellow of the American Institute for Medical and Biological Engineering, and holds joint appointments in the UA departments of systems and industrial engineering, and ophthalmology and vision science.



Source: Arizona University

Unique salt allows energy production to move inland

Engineerblogger
March 2, 2012

Microbial reverse dialysis test cell. Credit PSU

Production of energy from the difference between salt water and fresh water is most convenient near the oceans, but now, using an ammonium bicarbonate salt solution, Penn State researchers can combine bacterial degradation of waste water with energy extracted from the salt-water fresh-water gradient to produce power anywhere.

"We are taking two technologies, each having limitations, and putting them together," said Bruce E. Logan, Kappe Professor of Environmental Engineering. "Combined, they overcome the limitations of the individual technologies."

The technologies Logan refers to are microbial fuel cells (MFC) -- which use wastewater and naturally occurring bacteria to produce electricity -- and reverse electrodialysis (RED) -- which produces electricity directly from the salinity gradient between salty and fresh water. The combined technology creates a microbial reverse-electrodialysis cell (MRC). The researchers describe MRCs in today's (March 1) edition of Science Express.

RED stacks extract energy from the ionic difference between fresh water and salt water. A stack consists of alternating ion exchange membranes -- positive and negative -- with each RED membrane pair contributing additively to the electrical output. Unfortunately, using only RED stacks to produce electricity is difficult because a large number of membranes is required when using water at the electrodes, due to the need for water electrolysis.

Using exoelectrogenic bacteria -- bacteria found in wastewater that consume organic material and produce an electric current -- reduces the number of stacks needed and increases electric production by the bacteria.

Logan, working with Roland Cusick, graduate student in environmental engineering, and postdoctoral fellow Younggy Kim, placed a RED stack between the electrodes of an MFC to form the MRC.

While the researchers previously showed that an MRC can work with natural seawater, the organic matter in water will foul the membranes without extensive precleaning and treatment of the water. Seawater use restricts MRC operation to coastal areas, but food waste, domestic waste and animal waste contain about 17 gigawatts of power throughout the U.S. One nuclear reactor typically produces 1 gigawatt.

Rather than rely on seawater, the researchers used ammonium bicarbonate, an unusual salt. An ammonium bicarbonate solution works similarly to seawater in the MRC and will not foul the membranes. The ammonium bicarbonate is also easily removed from the water above 110 degrees Fahrenheit. The ammonia and carbon dioxide that make up the salt boil out, and are recaptured and recombined for reuse.

"Waste heat makes up 7 to 17 percent of energy consumed in industrial processes," said Logan. "There is always a source of waste heat near where this process could take place and it usually goes unused."

The researchers tested their ammonium bicarbonate MRC and found that the initial production of electricity was greater than that from an MRC using seawater.

"The bacteria in the cell quickly used up all the dissolved organic material," said Logan. "This is the portion of wastewater that is usually the most difficult to remove and requires trickling filters, while the particulate portion which took longer for the bacteria to consume, is more easily removed."

The researchers tested the MRC only in a fill and empty mode, but eventually a stream of wastewater would be run through the cell. According to Logan, MRCs can be configured to produce electricity or hydrogen, making both without contributing to greenhouse gases such as carbon dioxide. The MRC tested produced 5.6 watts per square meter.

Logan also said not having to process wastewater would save about 60 gigawatts.

The King Abdullah University of Science and Technology supported this work.

Source: Pennsylvania State University

Hydrogen from Acidic Water: Researchers Develop a Potential Low Cost Alternative to Platinum for Splitting Water

Engineerblogger
Feb 10, 2012

Using a molybdenite complex and the PY5Me2 ligand, Berkeley Lab researchers synthesized a molecule that mimics catalytically active triangular molybdenum disulfide edge-sites. The result is an entire layer of catalytically active material. Molybdenum atoms are shown as green, sulfur as yellow.

A technique for creating a new molecule that structurally and chemically replicates the active part of the widely used industrial catalyst molybdenite has been developed by researchers with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). This technique holds promise for the creation of catalytic materials that can serve as effective low-cost alternatives to platinum for generating hydrogen gas from water that is acidic.

Christopher Chang and Jeffrey Long, chemists who hold joint appointments with Berkeley Lab and the University of California (UC) Berkeley, led a research team that synthesized a molecule to mimic the triangle-shaped molybdenum disulfide units along the edges of molybdenite crystals, which is where almost all of the catalytic activity takes place. Since the bulk of molybdenite crystalline material is relatively inert from a catalytic standpoint, molecular analogs of the catalytically active edge sites could be used to make new materials that are much more efficient and cost-effective catalysts.

“Using molecular chemistry, we’ve been able to capture the functional essence of molybdenite and synthesize the smallest possible unit of its proposed catalytic active site,” says Chang, who is also an investigator with the Howard Hughes Medical Institute (HHMI). “It should now be possible to design new catalysts that have a high density of active sites so we get the same catalytic activity with much less material.”

Says Long, “Inorganic solids, such as molybdenite, are an important class of catalysts that often derive their activity from sparse active edge sites, which are structurally distinct from the inactive bulk of the molecular solid. We’ve demonstrated that it is possible to create catalytically active molecular analogs of these sites that are tailored for a specific purpose. This represents a conceptual path forward to improving future catalytic materials.”

Chang and Long are the corresponding authors of a paper in the journal Science describing this research titled “A Molecular MoS2 Edge Site Mimic for Catalytic Hydrogen Generation.” Other authors are Hemamala Karunadasa, Elizabeth Montalvo, Yujie Sun and Marcin Majda.

Molybdenite is the crystalline sulfide of molybdenum and the principal mineral from which molybdenum metal is extracted. Although commonly thought of as a lubricant, molybdenite is the standard catalyst used to remove sulfur from petroleum and natural gas for the reduction of sulfur dioxide emissions when those fuels are burned. Recent studies have shown that in its nanoparticle form, molybdenite also holds promise for catalyzing the electrochemical and photochemical generation of hydrogen from water. Hydrogen could play a key role in future renewable energy technologies if a relatively cheap, efficient and carbon-neutral means of producing it can be developed.

Currently, the best available technique for producing hydrogen is to split water molecules into molecules of hydrogen and oxygen using platinum as the catalyst. However, with platinum going for more than $2,000 an ounce, the market is wide open for a low cost alternative catalyst. Molybdenite is far more plentiful and about 1/70th the cost of platinum, but poses other problems.

“Molybdenite has a layered structure with multiple microdomains, most of which are chemically inert,” Chang says. “High-resolution scanning tunneling microscopy studies and theoretical calculations have identified the triangular molybdenum disulfide edges as the active sites for catalysis; however, preparing molybdenite with a high density of functional edge sites in a predictable manner is extremely challenging.”

Chang, Long and their research team met this challenge using a pentapyridyl ligand known as PY5Me2 to create a molybdenum disulfide molecule that, while not found in nature, is stable and structurally identical to the proposed triangular edge sites of molybdenite. It was shown that these synthesized molecules can form a layer of material that is analogous to constructing a sulfide edge of molybdenite.

“The electronic structure of our molecular analog can be adjusted through ligand modifications,” Long says. “This suggests we should be able to tailor the material’s activity, stability and required over-potential for proton reduction to improve its performance.”

In 2010, Chang and Long and Hemamala Karunadasa, who is the lead author on this new Science paper, used the PY5Me2 ligand to create a molybdenum-oxo complex that can effectively and efficiently catalyze the generation of hydrogen from neutral buffered water or even sea water. Molybdenite complexes synthesized from this new molecular analog can just as effectively and efficiently catalyze hydrogen gas from acidic water.

“We’re now looking to develop molecular analogs of active sites in other catalytic materials that will work over a range of pH conditions, as well as extend this work to photocatalytic systems” Chang says.

Adds Long, “Our molecular analog for the molybdenite active site might not be a replacement for any existing catalytic materials but it does provide a way to increase the density of active sites in inorganic solid catalytic materials and thereby allow us to do more with less.”

This research was supported by the DOE Office of Science, in part through the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub.


Source: Lawrence Berkeley National Laboratory

Development of Material for Quick, Simple Removal of Toxic Arsenic in Drinking Water

Engineerblogger
Jan 19, 2012

Prof. Dr. Sherif A. El-Safty, a Principal Researcher of the Materials Recycling Design Group, Research Center for Strategic Materials, National Institute for Materials Science developed a nanomaterial which enables simple detection and removal of arsenic from drinking water

Prof. Dr. Sherif El-Safty, a Principal Researcher of the Materials Recycling Design Group (Group Leader: Dr. Kohmei Halada), Research Center for Strategic Materials, National Institute for Materials Science (President: Prof. Sukekatsu Ushioda) developed a nanomaterial which enables simple detection and removal of arsenic from drinking water. This nanomaterial responds to warnings that as many as 60 million people live in contaminated areas in Southeast Asia without safe drinking water.

The nanomaterial is a further developed for heavy metal ion sensors for lead (Pb), mercury (Hg), etc. and adsorbent materials, which Dr. El-Safty developed previously for a rare metal adsorption/recovery materials such as cobalt (Co), palladium (Pd), etc. and radioactive element adsorbents for cesium (Cs), strontium (Sr), etc. As a Principal Researcher whom he originally livid at the Middle East, where a clean water is particularly precious, Dr. El-Safty devoted himself to the development of this material in order to save the world’s drinking water.

Groundwater in Asia, South America, and Africa is now widely contaminated with arsenic. Arsenic contamination of the drinking water for 35 million people in Bangladesh is especially well-known. Long-term ingestion of this water causes serious disorders of the skin, nervous system, and cardiovascular system, and can also cause health problems in the form of frequent development of cancers. Although the United Nations and the governments of individual nations have taken countermeasures over many years, it was difficult to develop an arsenic removal method that is inexpensive, simple, and easy to use in treatment of everyday drinking water.

In the developed technology, the inner walls of nanoporous substances, namely a high order mesoporous (HOM) structures, are densely packed with a functional group which is sensitive and selective for capturing arsenic. When even a trace amount of arsenic is present in water, these nanomaterial captors can quickly adsorbed and removed arsenic. As a distinctive feature, the detection/removal of arsenic can easily be confirmed because the color of the nanomaterial captors changes in the adsorption stage with the same frequency of human eyes, showing the user that the removal has occurred.
As one particular advantage of this technology, the potential use is not limited to large-volume water treatment plants. Because its features include high sensitivity, low cost, visualization of results, light weight, and high speed, it can also be used easily by individual persons. As a result, the threat of arsenic can be greatly reduced when the development of new water sources in the developing countries and elsewhere is achieved. Efforts will be made to popularize this new device in many urgent regions, as a technology that can secure the safe water on an everyday basis.


Source:  National Institute for Materials Science (NIMS)

Project to pour water into volcano to make power

Engineerblogger
Jan 16, 2011

In this May 16, 2008, file photo, Newbery Crater project drilling manager Fred Wilson stands near a drilling rig at the Newberry Crater geothermal project as he describes the work near LaPine, Ore. Geothermal energy developers plan to pump 24 million gallons of water into the side of the dormant Central Oregon volcano this summer to demonstrate new technology they hope will give a boost to a green energy sector that has yet to live up to its promise. (AP Photo/Don Ryan, File)

Geothermal energy developers plan to pump 24 million gallons of water into the side of a dormant volcano in Central Oregon this summer to demonstrate new technology they hope will give a boost to a green energy sector that has yet to live up to its promise.

They hope the water comes back to the surface fast enough and hot enough to create cheap, clean electricity that isn't dependent on sunny skies or stiff breezes—without shaking the earth and rattling the nerves of nearby residents.

Renewable energy has been held back by cheap natural gas, weak demand for power and waning political concern over global warming. Efforts to use the earth's heat to generate power, known as geothermal energy, have been further hampered by technical problems and worries that tapping it can cause earthquakes.

Even so, the federal government, Google and other investors are interested enough to bet $43 million on the Oregon project. They are helping AltaRock Energy, Inc. of Seattle and Davenport Newberry Holdings LLC of Stamford, Conn., demonstrate whether the next level in geothermal power development can work on the flanks of Newberrry Volcano, located about 20 miles south of Bend, Ore.

"We know the heat is there," said Susan Petty, president of AltaRock. "The big issue is can we circulate enough water through the system to make it economic."

The heat in the earth's crust has been used to generate power for more than a century. Engineers gather hot water or steam that bubbles near the surface and use it to spin a turbine that creates electricity. Most of those areas have been exploited. The new frontier is places with hot rocks, but no cracks in the rocks or water to deliver the steam.

To tap that heat—and grow geothermal energy from a tiny niche into an important source of green energy—engineers are working on a new technology called Enhanced Geothermal Systems.

"To build geothermal in a big way beyond where it is now requires new technology, and that is where EGS comes in," said Steve Hickman, a research geophysicist with the U.S. Geological Survey in Menlo Park, Calif.

Wells are drilled deep into the rock and water is pumped in, creating tiny fractures in the rock, a process known as hydroshearing.

Cold water is pumped down production wells into the reservoir, and the steam is drawn out.
Hydroshearing is similar to the process known as hydraulic fracturing, used to free natural gas from shale formations. But fracking uses chemical-laden fluids, and creates huge fractures. Pumping fracking wastewater deep underground for disposal likely led to recent earthquakes in Arkansas and Ohio.

Fears persist that cracking rock deep underground through hydroshearing can also lead to damaging quakes. EGS has other problems. It is hard to create a reservoir big enough to run a commercial power plant.

Progress has been slow. Two small plants are online in France and Germany. A third in downtown Basel, Switzerland, was shut down over earthquake complaints. A project in Australia has had drilling problems.

A new international protocol is coming out at the end of this month that urges EGS developers to keep projects out of urban areas, the so-called "sanity test," said Ernie Majer, a seismologist with the Lawrence Berkeley National Laboratory. It also urges developers to be upfront with local residents so they know exactly what is going on.

AltaRock hopes to demonstrate a new technology for creating bigger reservoirs that is based on the plastic polymers used to make biodegradable cups.

It worked in existing geothermal fields. Newberry will show if it works in a brand new EGS field, and in a different kind of geology, volcanic rock, said Colin Williams, a USGS geophysicist also in Menlo Park.
The U.S. Department of Energy has given the project $21.5 million in stimulus funds. That has been matched by private investors, among them Google with $6.3 million.

Majer said the danger of a major quake at Newbery is very low. The area is a kind of seismic dead zone, with no significant faults. It is far enough from population centers to make property damage unlikely. And the layers of volcanic ash built up over millennia dampen any shaking.

But the Department of Energy will be keeping a close eye on the project, and any significant quakes would shut it down at least temporarily, he said. The agency is also monitoring EGS projects at existing geothermal fields in California, Nevada and Idaho.

"That's the $64,000 question," Majer said. "What's the biggest earthquake we can have from induced seismicity that the public can worry about."

Geologists believe Newberry Volcano was once one of the tallest peaks in the Cascades, reaching an elevation of 10,000 feet and a diameter of 20 miles. It blew its top before the last Ice Age, leaving a caldera studded with towering lava flows, two lakes, and 400 cinder cones, some 400 feet tall.

Although the volcano has not erupted in 1,300 years, hot rocks close to the surface drew exploratory wells in the 1980s.

Over 21 days, AltaRock will pour 800 gallons of water per minute into the 10,600-foot test well, already drilled, for a total of 24 million gallons. According to plan, the cold water cracks the rock. The tiny plastic particles pumped down the well seal off the cracks. Then more cold water goes in, bypassing the first tier, and cracking the rock deeper in the well. That tier is sealed off, and cold water cracks a third section. Later, the plastic melts away.

Seismic sensors produce detailed maps of the fracturing, expected to produce a reservoir of cracks starting about 6,000 feet below the surface, and extending to 11,000 feet. It would be about 3,300 feet in diameter.

The U.S. Bureau of Land Management released an environmental assessment of the Newberry project last month that does not foresee any problems that would stop it. The agency is taking public comments before making a final decision in coming months.

No power plant is proposed, but one could be operating in about 10 years, said Doug Perry, president and CEO of Davenport Newberry.

EGS is attractive because it vastly expands the potential for geothermal power, which, unlike wind and solar, produces power around the clock in any weather.

Natural geothermal resources account for about 0.3% of U.S. electricity production, but a 2007 Massachusetts Institute of Technology report projected EGS could bump that to 10% within 50 years, at prices competitive with fossil-fuels.

Few people expect that kind of timetable now. Electricity prices have fallen sharply because of low natural gas prices and weak demand brought about by the Great Recession and state efficiency programs.

But the resource is vast. A 2008 USGS assessment found EGS throughout the West, where hot rocks are closer to the surface than in the East, has the potential to produce half the country's electricity.

"The important question we need to answer now," said Williams, the USGS geophysicist who compiled the assessment, "is how geothermal fits into the renewable energy picture, and how EGS fits. How much it is going to cost, and how much is available."

Source: The Associated Press

Millennium Project: The Falkirk Wheel

Engineerblogger
Jan 12, 2012

 

As the Falkirk Wheel approaches its 10th anniversary, its owners couldn't be more delighted in how the one-of-a-kind boat lift has transformed Scotland's once-forgotten and neglected canal system into a thriving recreational and tourist attraction. The 35-m-high, 1,500-tonne structure, internationally recognized as an engineering marvel, reconnects the Forth & Clyde Canal and the Union Canal, a vertical drop of 18 m, and provides water transport between Edinburgh and Glasgow.

Conceived in the 1990s as part of the United Kingdom's Millennium Project, its owners, British Waterways Scotland, were seeking a novel, landmark design to take an Industrial Revolution-era project into the new century. The two canals had been connected through a series of 11 locks that were taken out of service in the 1930s when overland transport by road and rail supplanted the canal system. The canals were closed altogether in the 1960s. The Falkirk Wheel, a rotating lift operating through what BWS Business Development Manager Richard Millar calls a "simple and elegant design," move two gondolas on opposite arms from one level to the other. Each gondola, or caisson, contains at least 250,000 L of water and can carry up to eight boats at a time.
  

Synchronous gears placed within the wheel ensure that the gondolas stay in the horizontal plane during lifting.

Locks and Lifts

To reach the wheel, boats moving through the Union Canal must still negotiate two locks, sail through a tunnel excavated beneath the Roman-era Antonine Wall, and proceed through a stretch of reinforced-concrete aqueduct . All are part of the overall £78-million Millennium Project. Still, there is a height difference of 11 ft between the wheel and the main channel of the Union Canal; the aqueduct could not be positioned higher because of its location to the Antonine Wall, which marks the northernmost boundary of Rome's empire in Brittania. The lift then lowers one gondola to a loading basin and entry to the Forth & Clyde Canal, and raises the other to the aqueduct and the Union Canal.

Design is meant to resemble a Celtic cross.

The wheel actually consists of two sets of opposing arms designed to resemble a double-headed Celtic axe. Designed by architect RMJM, they extend 15 m from the 3.5-m-diameter central axle and are placed 25 m apart. Each is fitted between the arms with a diametrically opposed water-filled caisson, or gondola, mounted on bearings riding on a circular rail. When one caisson is lowered, its opposite rises (see video of the Falkirk Wheel).

Simplicity

The weight in each of the gondolas remains the same, no matter how many boats are being lifted or lowered. The mechanics follow the Archimedes principle of displacement: the mass of the vessels moving into the gondola will displace an exactly proportional volume of water. This keeps the wheel balanced, allowing both gondolas to rotate 180 degrees in just five and one-half minutes. The efficiency of the design allows it rotate using very little power, just 22.5 kW to power the electric motors.

MG Bennett & Associates, Rotherham, UK, known now as Bennett Atkins and a part of Atkins Global, designed the mechanical and electrical systems for the project, working with structural engineer Tony Gee and Partners under a contract with Butterley Engineering. Butterley was awarded the contract to design and construct the wheel from Bachy/Solentanche and Morrison Construction Joint Venture, which won the overall contract to design and build the new canal section, tunnel, and aqueduct as well as the wheel and receiving basin.

Aqueduct for the Union Canal leads to the upper portion of the Falkirk Wheel.

The existing design was refined from one that envisioned four gondolas with an interlocking gear system. "The interesting thing about the Falkirk Wheel is it is an integration of different areas of engineering," says Nicholas Cooper, who led the work for Bennett and now is engineering director for Atkins' energy business. "It is a machine held together by a structure."

Engineering Integration

To make it work, Bennett drew on its experience in tunneling and undersea engineering to design a drive system based on those of tunnel-boring machines as well as air-lock doors to provide seals at each end of the gondolas and the canal gates.

Hydraulic rams are used to open and close the gates, release the seals and stabilize the gondolas. As the gondolas contain no power units, Bennett drew on its subsea pipeline experience to design a hydraulic connection to the ram using a "hot stab," an external link that extends from the structure into a port in the gondola where it connects the hydraulic circuit.

A pair of 4-m-diameter, three-row slewing bearings are incorporated into the drive system. Located at the ends of the axle, the outer rings of the bearings are bolted to the fixed support structure and the inner rings are bolted to the tubular axle. The inside diameter of the inner ring has gear teeth that mesh with a gearbox within the axle.

Finally, to ensure the gondolas remain stable and in the horizontal plane during rotation, the designers used a series of synchronous gears cut with a shallow involute angle commonly found in old clocks. The concept allows the gears to accept structural deflection as the gondolas move.

And they move enough to handle 130,000 to 150,000 people traveling the canals annually, says Millar. The wheel takes 15 minutes to move boats from one level to the next, compared to the half-day traverse of the old 11-step lock system.

"We were looking for something to grab the people's imagination," says Millar. "We were looking for something that would take us to the 21st Century."

A recent inspection showed the structure is aging gracefully as it enters its second decade of operation. With its 125-year design life and robust popularity, the Falkirk Wheel is fulfilling its owner's desire.

Source: ASME

Metal oxide simulations could help green technology

Engineerblogger
Jan 12, 2012

Computer simulations show that metal oxides in water go through many short-lived shapes and structures. (William Casey/UC Davis graphic)

University of California, Davis, researchers have proposed a radical new way of thinking about the chemical reactions between water and metal oxides, the most common minerals on Earth. Their work appears in the current issue of the journal Nature Materials.

The new paradigm could lead to a better understanding of corrosion and how toxic minerals leach from rocks and soil. It could also help in the development of “green” technology: new types of batteries, for example, or catalysts for splitting water to produce hydrogen fuel.

“This is a global change in how people should view these processes,” said William Casey, UC Davis professor of chemistry and co-author of the study with James Rustad, a former geology professor at UC Davis who now works as a scientist at Corning Inc. in New York.

Previously, when studying the interactions of water with clusters of metal oxides, researchers tried to pick and study individual atoms to assess their reactivity. But “none of it really made sense,” Rustad said.

Using computer simulations developed by Rustad, and comparing the resulting animations with lab experiments by Casey, the two found that the behavior of an atom on the surface of the cluster can be affected by an atom some distance away.

Instead of moving through a sequence of transitional forms, as had been assumed, metal oxides interacting with water fall into a variety of “metastable states” — short-lived intermediates, the researchers found.

For example, in one of Rustad’s animations, a water molecule approaches an oxygen atom on the surface of a cluster. The oxygen suddenly pulls away from another atom binding it into the middle of the cluster and leaps to the water molecule. Then the structure collapses back into place, ejecting a spare oxygen atom and incorporating the new one.

The U.S. Department of Energy and the National Science Foundation sponsored the research.

Source: University of California, Davis

Eco Wave Power Company is Taking the Fast Track to Success

Engineerblogger
Jan 9, 2012

Test Pool: Credit: Eco Wave Power

Eco Wave Power has completed the construction and testing phase of its first sea wave energy generation models the "Wave Clapper", and the "Power Wing".

The testing took place in the wave pool of the Hydro-Mechanical National Institute of Kiev . The "wave pool", 2.5 meters depth, and 18 meters length, provided Eco Wave Power with the perfect conditions for testing the unique wave energy generation technologies under controlled wave heights and wave periods.

Among the different tests, Eco Wave Power has examined the characteristics of 8 different unique floaters shapes (all with the same volume), through the following experiments: Measuring Voltage output in different wave heights, and different wave periods, Measuring the influence of side waves on the floaters and the connections, Examining different effects originating from the floaters' shapes, Connecting the floaters to different electric devices and showing a stable electric supply (with and without an accumulator), Examining the influence of floaters in proximity to each other, Examining the option to unite all floaters to one electric grid and charge a common accumulator, as well as -Examining the floaters' storm-protection Mechanisms.

All the experiments were monitored by officials from the Hydro-Mechanical Institute, and some remarks were made with regard to potential improvements to the shapes of the floaters. Eco Wave Power has immediately applied such remarks and the tests results were determined to be successful.

The Protocol submitted to Eco Wave Power, by the Hydro-Mechanic Institute, has concluded the experiments as following: "All floaters of Eco Wave Power Company have proved their workability… According to the results of the tests, we have reached a decision to recommend continuing the development of the green energy generation system that is based on such principles, and enlarge the model to greater sizes."

Therefore, it has been decided to move on to the following stage, which is the construction and testing of the medium scale model, capable of producing 5KW from each floater. The model will be composed of one "Wave Clapper" floater, and one "Power Wing" floater, in the size of 2.5 meters each. The construction of the medium scale models has already begun, and the testing will be taking place in early 2012.

As can be seen at Eco Wave Power's website, the company has already secured funding for three ocean energy generation models, the last of which will be a full-size commercial scale power plant, with the ability to supply electricity to at least 1000 households.

Mr. David Leb , the founder of the company, has stated that: "We are a young and innovative company in the field of ocean energy. As a result, we believe in a fast, yet reliable, progress. Our competitors in the ocean energy sphere had spent 5 to 15 years researching the ocean energy field, resulting with no commercial scale devices available for sale and implementation. We want to be different. We want to be able to offer our commercial scale devices within the shortest time frame, and for the most attractive prices."

As said by John Henry Newman : "Nothing would be done at all if a man waited until he could do it so well that no one could find fault with it."

Our system is being developed to produce electricity for a cheaper price than traditional energy generation methods such as coal, gas and oil and also cheaper than renewable energy generation methods such as wind or solar. This will be achieved by using low cost materials, low maintenance prices and low maintenance periods, still yielding-long life expectancies.

3D illustration. Credit: Eco Wave Power

 The Eco Wave Power wave energy converter is a simple and inexpensive technology to harvest wave energy from high and low waves. It is designed to be simple and robust while offering technical advantages over other renewable energy generation systems.

A short video presentation of the sea wave energy generation unit test.



Source: PR Newswire