Wednesday, 26 March 2014

Mother-of-pearl inspires super-strong material


Whether traditional or derived from high technology, ceramics all have the same flaw: they are fragile. Yet this characteristic may soon be a thing of the past: a team of researchers led by the Laboratoire de Synthèse et Fonctionnalisation des Céramiques (CNRS/Saint-Gobain), in collaboration with the Laboratoire de Géologie de Lyon: Terre, Planètes et Environnement (CNRS/ENS de Lyon/Université Claude Bernard Lyon 1) and the Laboratoire Matériaux: Ingénierie et Science (CNRS/INSA Lyon/ Université Claude Bernard Lyon 1), has recently presented a new ceramic material inspired by mother-of-pearl from the small single-shelled marine mollusk abalone. This material, almost ten times stronger than a conventional ceramic, is the result of an innovative manufacturing process that includes a freezing step. This method appears to be compatible with large-scale industrialization and should not be much more expensive than the techniques already in use. The artificial mother-of-pearl, which retains its properties at temperatures of at least 600°C, could find a wealth of applications in industry and reduce the weight or size of ceramic elements in motors and energy generation devices. This work was published on March 23, 2014 on the website of the journal Nature Materials.

Toughness, i.e. the ability of a material containing a crack to resist fracture, is considered to be the Achilles heel of ceramics. To compensate for their intrinsic fragility, these are sometimes combined with tougher materials such as metals or polymers -- generally leading to varying degrees of limitations. For example, polymers cannot resist temperatures above 300°C, which restricts their use in motors or ovens.

A material similar to ceramic, although extremely tough, is found in nature.. Mother-of-pearl, which covers the shells of abalone and some bivalves, is 95% composed of calcium carbonate (aragonite), an intrinsically fragile material that is nonetheless very tough. Mother-of-pearl can be seen as a stack of small bricks, welded together with mortar composed of proteins. Its toughness is due to its complex, hierarchical structure where cracks must follow a tortuous path to propagate. It is this structure that inspired the researchers.






As a base ingredient, the team from the Laboratoire de Synthèse et Fonctionnalisation des Céramiques (CNRS/Saint-Gobain) used a common ceramic powder, alumina, in the form of microscopic platelets. To obtain the layered mother-of-pearl structure, they suspended this powder in water. The colloidal suspension (1) was then cooled to obtain controlled ice crystal growth, causing alumina to self-assemble in the form of stacks of platelets. The final material was subsequently obtained from a high temperature densification step. This artificial mother-of-pearl is ten times tougher than a conventional alumina ceramic. This is because a crack has to move round the alumina "bricks" one by one to propagate. This zigzag pathway prevents it from crossing the material easily.

One of the advantages of the process is that it is not exclusive to alumina.. Any ceramic powder, as long as it is in the form of platelets, can self-assemble via the same process, which could easily be used on an industrial scale. This bio-inspired material's toughness for equivalent density could make it possible to produce smaller, lighter parts with no significant increase in costs. This invention could become a material of choice for applications subjected to severe constraints in fields ranging from energy to armor plating

Researchers suggest to Harvest the Earth's infrared energy

Man has shown considerable ingenuity in seeking out renewable energy – chasing after wind, tides, biomass, sunshine and more. But there is one source that we have not yet tapped – the 10^17 W of infrared thermal radiation emitted by the Earth into outer space as a result of the warmth it receives from the Sun.

"Wherever there is an opportunity to generate energy, scientists should be working on it," says Steve Byrnes of Harvard University in US. "Although there is an enormous amount of infrared energy flowing in the environment, it has not been properly evaluated in the context of energy generation. The rapid improvement in mid-infrared technology over the past 20 years…enables us to imagine new mid-infrared devices and applications."

Byrnes and colleagues at Harvard, including Federico Capasso, co-inventor of the infrared quantum-cascade laser, have investigated two possible ways to make an "emissive energy harvester" (EEH) that could extract some of this infrared power.

• Two possible approaches:
The techniques are broadly comparable to the two types of solar electricity generation, explains Byrnes. "In the first, 'solar thermal', sunlight heats an object and a turbine runs on the temperature difference between the hot object and the cooler environment," he says. "We can make a 'thermal EEH' in an analogous way: an object radiatively cools and a turbine runs on the temperature difference between the cool object and the warmer environment."

The team envisages that such a thermal EEH device would consist of a "hot" plate at the temperature of the Earth and air, with a "cold" plate on top made from a very emissive material that is cooled by radiating heat to the sky. The surface of the Earth, at a temperature of about 275–300 K, is much warmer than the 3 K of outer space.

The team calculated how much power this type of design could generate at a test site at Lamont, Oklahoma, that had measurements of downwelling long-wave infrared radiation. The data for the amount of infrared radiation received helped the researchers calculate the ideal performance of the device given the likely amount of infrared radiation emitted and the temperature conditions.

• Working day and night


Year-round, the devices would produce an average of 2.7 W/m^2 , or 0.06 kWh/m^2 per day, the researchers calculated. "We have found that infrared emissions can generate a substantial amount of energy, during both day and night," says Byrnes.

In principle, the Earth has enough EEH power to supply all of humanity many times over, write the scientists in PNAS , but this power density is quite low for large-scale generation applications. For example, a photovoltaic panel with an efficiency of 1.5% would generate the same total energy at the Lamont site as an EEH. That said, heating the EEH devices with sunlight could boost their power generation by a factor of five. Because the devices work best when there is little downwelling radiation – either when the air is cold and dry (as may be the case in winter), or when the ground is hot (more typical conditions during the summer) – the power output would be roughly the same throughout the year. Over the course of a day, power would be likely to peak in the afternoon and evening, when the ambient temperature is highest.

• Optoelectronic harvesting:
The second option for solar power is "solar photovoltaic", where sunlight is converted directly into electric current. "We can make an 'optoelectronic EEH' in an analogous way," explains Byrnes. "An antenna radiates infrared radiation into the sky and by interacting with a diode it can directly create usable electrical power."

Sunday, 23 March 2014

A new algorithm improves the efficiency of small wind turbines

In recent years, mini wind energy has been developing in a spectacular way. However, level of efficiency of small wind turbines is low. To address this problem, the UPV/EHU's research group APERT (Applied Electronics Research Team) has developed an adaptative algorithm. The improvements that are applied to the control of these turbines will in fact contribute towards making them more efficient.

Small wind turbines tend to be located in areas where wind conditions are more unfavourable. "The control systems of current wind turbines are not adaptative; in other words, the algorithms lack the capacity to adapt to new situations," explained Iñigo Kortabarria, one of the researchers in the UPV/EHU'sAPERT research group. That is why "the aim of the research was to develop a new algorithm capable of adapting to new conditions or to the changes that may take place in the wind turbine," added Kortabarria. That way, the researchers have managed to increase the efficiency of wind turbines.

The speed of the wind and that of the wind turbine must be directly related if the latter is to be efficient. The same thing happens with a dancing partner. The more synchronised the rhythms of the dancers are, the more comfortable and efficient the dance is, and this can be noticed because the energy expenditure for the two partners is at a minimum level. To put it another way, the algorithm specifies the way in which the wind turbine adapts to changes. This is what the UPV/EHU researchers have focussed on: the algorithm, the set of orders that the wind turbine will receive to adapt to wind speed.

"The new algorithm adapts to the environmental conditions and, what is more, it is more stable and does not move aimlessly. The risk that algorithms run is that of not adapting to the changes and, in the worst case scenario, that of making the wind turbine operate in very unfavourable conditions, thereby reducing its efficiency.


• Efficiency is the aim:
Efficiency is one of the main concerns in the mini wind turbine industry. One has to bear in mind that small wind turbines tend to be located in areas where wind conditions are more unfavourable. Large wind turbines are located in mountainous areas or on the coast; however, small ones are installed in places where the wind conditions are highly variable. What is more, the mini wind turbine industry has few resources to devote to research and very often is unaware of the aerodynamic features of these wind turbines. All these aspects make it difficult to monitor the point of maximum power (MPPT Maximum Power Tracking) optimally."There has to be a direct relation between wind speed and wind turbine speed so that the monitoring of the maximum point of power is appropriate. It is important for this to be done optimally. Otherwise, energy is not produced efficiently," explained Iñigo Kortabarria.

Most of the current algorithms have not been tested under the conditions of the wind that blows in the places where small wind turbines are located. That is why the UPV/EHU researchers have designed a test bench and have tested the algorithms that are currently being used -- including the new algorithm developed in this piece of research -- in the most representative conditions that could exist in the life of a wind turbine with this power. "Current algorithms cannot adapt to changes, and therefore wind turbine efficiency is severely reduced, for example, when wind density changes," asserted Kortabarria.

A helicopter has just one rotor to provide lift. This machine has 18

If you’re disappointed that you don’t have a flying car in your driveway yet, you can take solace in the news that you soon might be able to test-drive an affordable private helicopter at a nearby dealership.

This past November, engineers at the German start-up e-volo celebrated the maiden flight of their battery-powered “volocopter,” which made several takeoffs and landings within a 72-foot-high hangar. In the coming year, engineers will continue working on the prototype, which the company boasts will be lighter, safer, quieter and greener than any other helicopter in the world.

That’s because a traditional helicopter uses one rotor to provide lift and a tail rotor to prevent the aircraft from spinning in circles. It maneuvers by changing the pitch of the two rotors. The volocopter has 18 small rotors mounted in a configuration that provides lift without causing the vehicle to spin. It navigates by changing the speed of individual rotors.

That design has advantages over a traditional helicopter. For one thing, it’s safer—in the event of a partial mechanical failure, the volocopter could land with as few as 12 operating rotors. And by forgoing large, heavy rotor blades, the aircraft is quieter, lighter and more energy efficient.

E-volo’s goal is to produce a volocopter capable of flying up to one hour before needing to recharge. That’s enough time for most people to commute to work—especially since they won’t be stuck in traffic.

Box-shaped pressure vessel for LNG developed by KAIST research team

Korean researchers successfully showcased the installation and operation of a box-shaped, high-pressure tank for the storage of liquefied natural gas in Pohang, Republic of Korea. The development was the first of its kind in the world.

Pressure vessels have many applications and are widely used within the petrochemical, energy, and other industrial sectors where the transport and storage of many types of pressurized gases and fluids are essential. Pressure vessels must be designed, manufactured, installed, and operated strictly in accordance with the appropriate codes and standards since they can, in cases of leak or rupture, pose considerable health and safety hazards.

Pressure vessels are normally designed in the form of a cylindrical or spherical tank. These shapes are, in principle, highly efficient in withstanding internal pressure, but rather inefficient in terms of space utilization. The tanks fit very poorly within a typically prismatic-shaped room. They cannot be packed closely together, so they do not efficiently utilize the overall space. Moreover, cylindrical or spherical tanks are not easily scalable to very large sizes because the wall thickness of the tank must increase proportionally to its overall radius. Therefore, a large pressure vessel unavoidably will have very thick walls, which are difficult and expensive to manufacture, requiring a great amount of thick-walled steel to be rolled, forged, and welded together.

KAIST researchers, sponsored by POSCO, a multinational steel-making company based in Pohang, Republic of Korea, have taken a turnabout approach to construct a pressure vessel that is neither cylindrical nor spherical. Professors Pål G. Bergan and Daejun Chang and of Ocean Systems Engineering at KAIST developed a box-type, large size pressure vessel for the storage and transportation of liquids such as liquefied petroleum gas (LPG), compressed natural gas (CNG), or liquefied natural gas (LNG).

The box-shaped pressure vessel has an internal, load-carrying lattice-type structure. The lattice pattern is modular in all three spatial directions, thereby effectively anchoring and balancing pressure forces on the external walls of the vessel. The modular lattice can easily be adapted to prescribed pressure levels as the overall volumetric dimensions are directly linked to the number of repetitive modules. A giant prismatic pressure vessel with a size of 20,000 m3 and a design pressure of 10 atmospheres (10 barg) can be built simply by scaling up a smaller size pressure vessel. It is interesting to note that the thickness of steel walls remains unchanged and that the weight of steel per unit storage volume goes down as the vessel size increases.

Professor Chang explained the benefit of a prismatic or box-shaped pressure vessel. "If we use cylindrical pressure vessels to supply LNG fuel for a large container ship, for example, many fuel tanks will be needed. Those tanks will take up large and valuable space onboard because the cylinders have to be lined up. In our case, however, much less space is needed. The operation of a ship becomes simpler with one fuel tank rather than with many. Furthermore, our box-type pressure vessel can be designed with dimensions that precisely fit a ship. For a container ship, there may be room for a substantially higher number of containers to be loaded than when using cylindrical vessels. In a case study on a 13,000 TEU container ship, the value of the increased transport capacity tuned out USD 8.4 million for one year of operation for one ship."

Friday, 21 March 2014

Different beautiful eyes of different animals


Mechanical Beauty


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Tuesday, 18 March 2014

Researchers develop new kind of internal combustion microengine

A team of researchers with members from Russia, The Netherlands and Germany has developed a new kind of microengine, based on the possible combustion of oxygen and hydrogen. In their paper published in Scientific Reports , the team describes how they built the new engine, how they think it works, and what it could mean for the development of future microsystems.



As scientists have built ever smaller devices, the need for ever smaller microengines has grown, unfortunately, the science for tiny engines hasn't kept pace. Those based on electrostatic forces aren't able to produce enough power and traditional combustion engines become less and less efficient as they are made smaller. In this new effort, the researchers built a tiny combustion engine in a new way that overcomes the problems of others before it, though they can't say for sure how it works.

The engine is very simple. The team built a tiny pressure chamber with a flexible membrane at one end, they then added wires inside that ran through a saltwater solution. Sending current through the wires caused hydrogen and oxygen in the water to disassociate into tiny bubbles (i.e. electrolysis). That caused an increase in pressure inside the chamber (approximately 3.6 bar) forcing the membrane to bend outwards (approximately 1.4 microns). Turning off the current caused the membrane to return to its natural shape, but oddly, it did so much faster than it should have due to dissipation—the researchers suspect that instead the gas was combusted back into water molecules. In any event, quickly cycling back and forth a membrane can be used as a force mechanism—an engine.

Remarkably, the new microengine is just 100×100×5 microns in size and was fabricated using silicon wafers covered with a layer of silicon rich nitride and platinum electrodes. The membrane was part of the wafer, etched from the back side.

The microengine produces a lot of torque for its size, and thus could very well serve as the basis for very tiny devices that need to either perform physical work (e.g. pump fluid), or move around (perhaps inside human blood vessels). At the same time, it's a certainty that the original team and others will set to work trying to nail down exactly why the engine works and to determine just how small such an engine could be.

Awesome Mechanical Creativity


An Airship The Size of a Football Field Could Revolutionize Travel

A UK design firm recently unvieled the Airlander, a football field-sized aircraft engineered to push the limits of transportation. Unlike planes, it can take off vertically, from just about any locale. And unlike helicopters, it can carry a payload of 50 tons and stay afloat for weeks, long enough to circumvent the globe—twice, creators say.



The Airlander—all 44,000 pounds if it—was designed, from the bottom up, to fill this void. With a full tank of gas, it is expected to stay airborne and operational for as long as three weeks. To boot, the company also says the airship— easily the world's largest aircraft—uses 80 percent less fuel compared to conventional airplanes and helicopters, which should appease the environmentally-conscious set to some degree. This is made possible partly due to the ship's lightweight and semi-rigid hull, which is comprised of special leathery Kevlar material that's flexible, yet strong enough to withstand the impact of a shotgun bullet, Daniels says.

What's a bit surprising, though, is that the entire structure, when filled with helium, is actually heavier than air. While the weight ratio allows it to stay grounded without being tethered, only a small amount of forward speed is required to execute a take-off, thanks to unique wing-shape fins that give it an aerodynamic boost. The company estimates as much as 40 percent of the lift comes from the ship's aerodynamic design and propulsion system working in tandem.

Once aloft, the aircraft can reach a maximum speed of about 100 miles per hour. It lands with the help of vectored propulsors, or in layman's terms, thrusters that gradually push the ship downward, reducing lift by about 25 percent. Beneath the aircraft, an air cushion landing system features amphibious pneumatic tubes that extend downward, enabling it to land just about anywhere. The Airlander, Daniels boasts, can vertically descend onto bodies of water, ice, desert and rugged terrains such as scrubland, making it especially ideal for delivering heavy equipment to remote oil and mining sites.

"The great thing about helium," he points out, "is that with each doubling in length of an airship, you get eight times the lifting capacity."

The original concept for the Airlander was so promising that, four years ago, the U.S. military decided to subsidize its development. However, the fate of the project took a turn. Budget cuts led to officials ultimately abandoning the idea, and the unfinished prototype was eventually sold back to Hybrid Air Vehicles for about $301,000—less than 1 percent of how much it cost to build.

Though the airship passed a flight test in August 2012 in Lakehurst, New Jersey, U.S. government officials determined it was still too heavy to be flown uninterrupted for more than a few days. The next test flight, over the city of Bedford, New Jersey, is scheduled for December. The company, which was recently awarded a £2.5 million ($4.1 million) government grant to build upon its existing technology, also plans to develop different models that can aid delivery in disaster relief or be deployed in hard-to-reach places, such as icy roads close to Canadian mines.

While there's no target date for when such a model may exist—no companies have commissioned them yet—it isn't unrealistic to imagine the ships could also someday be piloted as an alternative to commercial air travel, which, in its current state, Daniels describes as an "unpleasant means to get somewhere desirable."

Among the most encouraging signs: Bruce Dickinson, lead singer of the rock band Iron Maiden, has since signed on as one of the project's principal financial backers. For a group in need of believers, having the "Futureal" frontman onboard isn't a bad start.

3rd Law of Thermodynamics restored in spin ice films

A group of London-based scientists at the London Centre for Nanotechnology along with a team of researchers from the Universities if Cambridge and Oxford have discovered a process by which to utilize the Third Law of Thermodynamics and renew it within thin films of a magnetic material called spin ice.



Research has determined that thin films of spin ice contain highly practical properties could aid in the furthering of applications of the magnetic mirror of electricity which scientists named “magnetricity”. Previous studies have also established that there’s a limit to just how cold something can get. That limit is reported to be minus 273 degrees centigrade or “absolute zero”.

This is founded on the Third Law of Thermodynamics which is the general notion that absolute zero is equivalent to zero entropy. There is one exception to this law and that is spin ice. Again, at absolute zero, the entropy of any substance, defined as the measure of randomness of the atoms within it, should be zero.

When it comes to spin ice however, the atomic magnetic moments reportedly remain in the drop to absolute zero. For the first time, these scientists have produced a thin spin ice film. It’s only a few nanometers thick.

Professor Steve Bramwell of UCL Department of Physics and Astronomy noted: “Restoration of the Third Law in spin ice thin films adds an unexpected twist to the story of spin ice. How the Third Law (of Thermodynamics) is first violated and then restored in spin ice is an interesting question of basic physics”.

Doctor Laura Bovo of the UCL London Centre for Nanotechnology and leading author of the scientific team’s research paper stated:

“This result shows that we can use strain to drastically alter and control the spin ice state. It opens up new possibilities for the control and manipulation of magnetricity and magnetic monopoles in spin ice.” They added that this scientific revelation can aid in the use of spin ice in magnetic technology such as that found in computer hard disks which are generally built on thin magnetic films.

I Love Mechanical Engineering


Novel membrane reveals water molecules will bounce off a liquid surface.

Consider the nearest water surface: a half-full glass on your desk, a puddle outside your window, or a lake across town. All of these surfaces represent liquid-vapor interfaces, where liquid meets air. Molecules of water vapor constantly collide with these liquid surfaces: Some make it through the surface and condense, while others simply bounce off.



The probability that a vapor molecule will bounce, or reflect, off a liquid surface is a fundamental property of water, much like its boiling point. And yet, in the last century, there has been little agreement on the likelihood that a water molecule will bounce off the liquid surface.

"When a water vapor molecule hits a surface, does it immediately go into the liquid? Or does it come off and hit again and again, then eventually go in?" says Rohit Karnik, an associate professor of mechanical engineering at MIT. "There's a lot of controversy, and there's no easy way to measure this basic property."

Knowing this bouncing probability would give scientists an essential understanding of a variety of applications that involve water flow: the movement of water through soil, the formation of clouds and fog, and the efficiency of water-filtration devices.

This last application spurred Karnik and his colleagues -- Jongho Lee, an MIT graduate student in mechanical engineering, and Tahar Laoui, a professor at the King Fahd University of Petroleum and Minerals (KFUPM) in Saudi Arabia -- to study water's probability of bouncing. The group is developing membranes for water desalination; this technology's success depends, in part, on the ability of water vapor to flow through the membrane and condense on the other side as purified water.

By observing water transport through membranes with pores of various sizes, the group has measured a water molecule's probability of condensing or bouncing off a liquid surface at the nanoscale. The results, published in Nature Nanotechnology , could help in designing more efficient desalination membranes, and may also expand scientists' understanding of the flow of water at the nanoscale.

"Wherever you have a liquid-vapor surface, there is going to be evaporation and condensation," Karnik says. "So this probability is pretty universal, as it defines what water molecules do at all such surfaces."

• Getting in the way of flow:
One of the simplest ways to remove salt from water is by boiling and evaporating the water -- separating it from salts, then condensing it as purified water. But this method is energy-intensive, requiring a great deal of heat.

Karnik's group developed a desalination membrane that mimics the boiling process, but without the need for heat. The razor-thin membrane contains nanoscale pores that, seen from the side, resemble tiny tubes. Half of each tube is hydrophilic, or water-attracting, while the other half is hydrophobic, or water-repellant.
As water flows from the hydrophilic to the hydrophobic side, it turns from liquid to vapor at the liquid-vapor interface, simulating water's transition during the boiling process. Vapor molecules that travel to the liquid solution on the other end of the nanopore can either condense into it or bounce off of it. The membrane allows higher water-flow rates if more molecules condense, rather than bounce.

Designing an efficient desalination membrane requires an understanding of what might keep water from flowing through it. In the case of the researchers' membrane, they found that resistance to water flow came from two factors: the length of the nanopores in the membrane and the probability that a molecule would bounce, rather than condense.

In experiments with membranes whose nanopores varied in length, the team observed that greater pore length was the main factor impeding water flow -- that is, the greater the distance a molecule has to travel, the less likely it is to traverse the membrane. As pores get shorter, bringing the two liquid solutions closer together, this effect subsides, and water molecules stand a better chance of getting through.

But at a certain length, the researchers found that resistance to water flow comes primarily from a molecule's probability of bouncing. In other words, in very short pores, the flow of water is constrained by the chance of water molecules bouncing off the liquid surface, rather than their traveling across the nanopores. When the researchers quantified this effect, they found that only 20 to 30 percent of water vapor molecules hitting the liquid surface actually condense, with the majority bouncing away.

• A no-bounce design:
They also found that a molecule's bouncing probability depends on temperature: 64 percent of molecules will bounce at 90 degrees Fahrenheit, while 82 percent of molecules will bounce at 140 degrees. The group charted water's probability of bouncing in relation to temperature, producing a graph that Karnik says researchers can refer to in computing nanoscale flows in many systems.

Farmer uses scraps of metal to make his own homemade helicopter…parts include a joystick for a motorcycle and stainless steel tubes

Farmer Li Housheng, 52, from Ganzhou Village in Miluo, China, is determined to get his DIY aircraft flying. He started building his very own two-rota engines last year using a dismantled motorbike. Skeletons are made of angle iron and stainless steel tubes and each rotor is simply a welding of four steel plates.



During a test flight, Li claims he managed to get the ramshackle contraption a staggering 40cm off the ground.

His friends keep telling him it will never take off. But in the face of those who doubt him, farmer Li Housheng, 52, is determined to get his makeshift helicopter off the ground. He began building the twin-rota aircraft at his home in Ganzhou Village of Baitang Township in Miluo, China, last year, using an engine from an agricultural motorcycle. The skeletons are made of angle iron and stainless steel tubes while each rotor is simply a welding of four steel plates. It even includes an accelerator, a clutch and a joystick, all of which come from an agricultural motorcycle.

The helicopter recently completed a test flight with the fuselage hopping a staggering 40cm off the ground, according to Li.

Friday, 14 March 2014

Soft robotic fish moves like the real thing New robotic fish can change direction almost as rapidly as a real fish

Soft robots -- which don't just have soft exteriors but are also powered by fluid flowing through flexible channels -- have become a sufficiently popular research topic that they now have their own journal, Soft Robotics . In the first issue of that journal, out this month, MIT researchers report the first self-contained autonomous soft robot capable of rapid body motion: a "fish" that can execute an escape maneuver, convulsing its body to change direction in just a fraction of a second, or almost as quickly as a real fish can.



"We're excited about soft robots for a variety of reasons," says Daniela Rus, a professor of engineering, director of MIT's One Science Department and Artificial Intelligence Laboratory, and one of the researchers who designed and built the fish. "As robots penetrate the physical world and start interacting with people more and more, it's much easier to make robots safe if their bodies are so wonderfully soft that there's no danger if they whack you."

Another reason to study soft robots, Rus says, is that "with soft machines, the whole robotic planning problem changes." In most robotic motion-planning systems, avoiding collisions with the environment is the highest priority. That frequently leads to inefficient motion, because the robot has to settle for collision-free trajectories that it can find quickly. With soft robots, collision poses little danger to either the robot or the environment. "In some cases, it is actually advantageous for these robots to bump into the environment, because they can use these points of contact as means of getting to the destination faster," Rus says. But the new robotic fish was designed to explore yet a third advantage of soft robots: "The fact that the body deforms continuously gives these machines an infinite range of configurations, and this is not achievable with machines that are hinged," Rus says. The continuous curvature of the fish's body when it flexes is what allows it to change direction so quickly. "A rigid-body robot could not do continuous bending," she says.

• Escape velocity:
The robotic fish was built by Andrew Marchese, a graduate
engineer in MIT's and lead author on the new paper, where he's joined by Rus and postdoc Cagdas D. Onal. Each side of the fish's tail is bored through with a long, tightly undulating channel. Carbon dioxide released from a canister in the fish's abdomen causes the channel to inflate, bending the tail in the opposite direction. Each half of the fish tail has just two control parameters: the diameter of the nozzle that releases gas into the channel and the amount of time it's left open. In experiments, Marchese found that the angle at which the fish changes direction -- which can be as extreme as 100 degrees -- is almost entirely determined by the duration of inflation, while its speed is almost entirely determined by the nozzle diameter. That "decoupling" of the two parameters, he says, is something that biologists had observed in real fish.

"To be honest, that's not something I designed for," Marchese says. "I designed for it to look like a fish, but we got the same inherent parameter decoupling that real fish have." That points to yet another possible application of soft robotics, Rus says, in biomechanics. "If you build an artificial creature with a particular bio-inspired behavior, perhaps the solution for the engineered behavior could serve as a hypothesis for understanding whether nature might do it in the same way," she says.

Marchese built the fish in Rus' lab, where other researchers are working on printable robotics. He used the lab's 3-D printer to build the mold in which he cast the fish's tail and head from silicone rubber and the polymer ring that protects the electronics in the fish's guts.

• The long haul:
The fish can perform 20 or 30 escape maneuvers, depending on their velocity and angle, before it exhausts its carbon dioxide canister. But the comparatively simple maneuver of swimming back and forth across a tank drains the canister quickly. "The fish was designed to explore performance capabilities, not long-term operation," Marchese says. "Next steps for future research are taking that system and building something that's compromised on performance a little bit but increases longevity."

A new version of the fish that should be able to swim continuously for around 30 minutes will use pumped water instead of carbon dioxide to inflate the channels, but otherwise, it will use the same body design, Marchese says. Rus envisions that such a robot could infiltrate schools of real fish to gather detailed information about their behavior in the natural habitat.

"All of our algorithms and control theory are pretty much designed with the idea that we've got rigid systems with defined joints," says Barry Trimmer, a biology professor at Tufts University who specializes in biomimetic soft robots. "That works really, really well as long as the world is pretty predictable. If you're in a world that is not -- which, to be honest, is everywhere outside a factory situation -- then you start to lose some of your advantage."

The premise of soft robotics, Trimmer says, is that "if we learn how to incorporate all these other sorts of materials whose response you can't predict exactly, if we can learn to engineer that to deal with the uncertainty and still be able to control the machines, then we're going to have much better machines." The MIT researchers' robot fish "is a great demonstration of that principle," Trimmer says. "It's an early stage of saying, 'We know the actuator isn't giving us all the control we'd like, but can we actually still exploit it to get the performance we want?' And they're able to show that yes, they can."

In a driverless future, drivers will do anything else

Brew an espresso, watch a movie on a large screen, surf the Internet or simply sit and chat with friends? As automakers and technology firms steer towards a future of driverless cars , a Swiss think tank is at the Geneva Motor Show previous week showing off its vision of what vehicles might look like on the inside when people no longer have to focus on the road.



"Once I can drive autonomously, would I want to watch while my steering wheel turns happily from left to right?" asked Rinspeed founder and chief executive Frank Rinderknecht.

"No. I would like to do anything else but drive and watch the traffic. Eat, sleep, work, whatever you can imagine," he told AFP at the show, which opens its doors to the public Thursday.

Google is famously working on fully autonomous cars, and traditional carmakers are rapidly developing a range of autonomous technologies as well. With analysts expecting sales of self-driving, if not completely driverless, cars to begin taking off by the end of this decade, Rinderknecht insists it's time to consider how the experience of riding in a car will could be radically redefined.

Patting his shiny Xchange concept car, Rinderknecht says he envisages a future where car passengers will want to do the same kinds of things we today do to kill time on trains an airplanes.

So Rinspeed has revamped the interior of Tesla's Model S electric car to show carmakers how they might turn standard-sized vehicles into entertainment centres, offices and meeting spots wrapped into one.

The seats can slide, swivel, and tilt into more than 20 positions, allowing passengers to turn to face each other or a 32-inch screen in the back.

Up front too, an entertainment system lines the entire length of the dashboard, and the steering wheel can be shifted to allow passengers a better view of the screens.

Espresso anyone?
And of course there is an espresso machine. While brewing coffee, video conferencing and keeping an eye on your email at 120 kilometres an hour may sound like a fantasy today, Rinderknecht is convinced it could happen in the not too distanced future.

"We think this is what things could look like in a few years time," he said. Driving, he said, is on the cusp of being redefined, allowing people to take the wheel for pleasure, for instance while going over an Alpine pass, but handing over control of the car on tedious stretches.

"If I have to go three hours from Geneva to Zurich and it's congested, I'm not doing anything… I want to be doing something else," he said.

Carmakers at the Geneva Motor Show seemed to agree that vehicles that drive themselves, at least to a certain extent, are on the horizon.

Artificial muscle made of fishing line is 100 times stronger than yours

By taking simple sewing thread and fishing wire and giving it a twist, scientists have created artificial muscle that's 100 times stronger than human or animal sinew. The invention, described in the journal Science, could be useful for prosthetic limbs, humanoid robots, implanted medical devices and even wearable clothing. This wouldn't be the first artificial muscle out there: there are carbon nanotube yarns and metal wires, but they're often expensive or store relatively low amounts of energy compared to their competitors, scientists said.



These new high-strength polymer fibers, made out of cheap, everyday materials that cost about $5 per kilogram, draw their strength from their geometry. In experiments led out of the University of Texas at Dallas in Richardson, scientists took these thin fibers that were just a few hundred micrometers long and twisted them until they began to coil. (You can see this same effect yourself if you take a rubber band and twist it until it starts to collapse into larger loops.) As it coils, the twisted fiber cable becomes shorter and thicker, and then the researchers heat-treated it to make it set. The scientists found that if they made the fiber coil in the same direction as the twist, the fiber cable would contract. If the fiber was forced to coil in the opposite direction of its twist, the fiber cable would expand.

When they applied an energy source to the fibers-typically heat-the scientists got different versions of their artificial muscle fibers to contract by 49 percent. or to expand by 67 percent. They even produce 7.1 horsepower per kilogram, about the same power as a jet engine (when scaled down for size). And the fibers can last through millions of these cycles, making them very durable, reusable devices.

"Despite their small diameter, the fibers can be indefinitely long and used in large structures," Jinkai Yuan and. Philippe Poulin, scientists from the. University of Bordeaux in France who. were not involved in the paper, wrote in a commentary.

The scientists think this could be useful for a number of applications that need muscle fibers , whether getting the. faces of humanoid robots to move with more human-like expressions or getting prosthetic limbs better muscle. They could be used to automatically open and shut blinds in response to the outside climate. The researchers already have created a textile with pores that expand and contract in response to heat-which could lead the way to adaptable, breathable clothing.

Tuesday, 11 March 2014

Push Rod Valve Gear And OveShaft Cam Shaft.


German engineers develop interactive simulator for vehicle drivers

Maximize mileage, safety, or operating life? Driving behavior behind the wheel has a big influence on the vehicle. Fraunhofer researchers have developed a drive simulator designed to make the "human factor" more calculable for vehicle engineers.



Simulations are an important development tool in the automobile and utility vehicle industries -- they enable engineers to see into the future. The properties of vehicle components, such as how they respond in an accident, their reliability, or their energy efficiency can be investigated using simulations before the first component is manufactured. To continue to maintain the prediction power of the results, however, all of the influences that the vehicle is exposed to later on in actual operation must be taken into account -- including those of drivers and operators.

Researchers at the Fraunhofer Institute for Industrial Mathematics ITWM in Kaiserslautern, Germany, have developed an interactive driving simulator using RODOS (robot-based driving and operation simulator) with which realistic interaction between human and vehicle can be analyzed. "Driving behavior is a key factor that is often insufficiently accounted for in computational models," according to Dr. Klaus Dreßler of ITWM. No doubt there are algorithms that are supposed to represent the "human factor" in simulations -- however, these do not properly reflect the complexity of human behavior. For this reason, researchers at ITWM have shifted to a hybrid design for simulation. Hybrid here means a real person interacts with a simulation environment -- a well-known example of this is a flight simulator, in which pilots regularly practice extreme situations. In the automotive and utility-vehicle sector, only a few manufacturers have had this kind of facility at their disposal, as its development involves a lot of effort and expense.

The simulation facility's structure at ITWM consists of a real vehicle interior where the test driver can operate the steering wheel, accelerator, and brakes as usual. The vehicle interior is integrated into a 6-axis robotic system that looks like a gigantic gripper arm and can simulate acceleration, braking, or tight curves by leaning and rotating. "We have much greater room to maneuver than with the kinematic systems usually employed today. At the same time, the space requirements are comparatively quite low," according to project manager Michael Kleer.
For test drivers to behave authentically, they must have the feeling they are actually situated in a moving vehicle. If movements of the simulator do not match the visual impressions, this not only influences driver reactions, it can also lead to symptoms like kinetosis. Simulator sickness is triggered by contradictory sensory perceptions, the same way motion sickness or sea sickness is. "To prevent these unpleasant side effects, we have developed our motion cueing algorithms that generate the control signals for the robot in close cooperation with researchers in cognition," explains Dreßler. On the basis of this interdisciplinary knowledge, the motions of the simulator can be matched to visual input so they are perceived as very natural by the test drivers. At the same time, an enormous projection dome provides the external impression of real driving. 18 projectors provide a realistic 300 degree view of the situation for the driver. "You can imagine it as resembling an IMAX theater," according to Dreßler.

Driving simulations that also take into account the human effects on a vehicle may become more important in future. The increasing number of driver assistance systems will themselves make the human-machine interface in automobiles increasingly important. The demands placed on simulations will thus become increasingly more specific. "That is where we have an additional advantage with our approach: all the algorithms are proprietary in-house developments -- so we therefore can match the individual algorithm parameters to project-specific problems," says Kleer.

The simulation facility at ITWM has been in operation since July 2013 -- and two projects in collaboration with the Volvo Construction Equipment company are presently underway. From April 7 to 11 the technology will be shown at the Hannover Messe trade fair.

Friday, 7 March 2014

A Spacesuit for the Deep Ocean

An advanced diving suit could free deep-sea exploration from the confines of a submarine, making biological discovery and deep-sea construction easier than ever before.
 
The Vancouver-developed atmospheric diving system, or ExoSuit, is essentially a 530lb metal space suit re-designed for use underwater. Complete with 18 red rotary joints the Exosuit is a flexible, pressurized environment that simulates the atmospheric conditions found at sea level. Featuring a 1.6 horsepower engine, any user has the ability to “swim” while wearing the suit and can control their motion via thrusters that can propel them in any direction.



First used in 2012 by contractors J.F White, the $600,000 ExoSuit was originally put to work in the still ongoing construction of New York City’s 10.5 mile long Water Tunnel 3. While the ExoSuit has since been employed in the commercial world this summer it will join the Blue Water Expedition, an academic venture studying the bioluminescent fish off the coast of New England.

Lead by a consortium of Universities, the American Museum of Natural History (AMNH) and the J.F. White Company, the Blue Water Expedition will allow biologists to investigate many species without removing them from their native environment. This unprecedented feat – coupled with the ability to interact with and probe the alien environment of the deep ocean – could lead to a greater understanding of bioluminescence as a whole. Armed with a fiber optic cable tethered to a nearby vessel, a researcher within the suit will be able to communicate with colleagues immediately through the use of both cameras and microphones embedded within the suit.

 In a recent statement John Sparks, curator of the AMNH’s Department of Ichthyology said, "Our access to these deeper open-water and reef habitats has been limited, which has restricted our ability to investigate the behavior and flashing patterns of bioluminescent organisms, or to effectively collect fishes and invertebrates from deep reefs … The Exosuit could get us one step closer to achieving these goals."

In the end, the ExoSuit may prove to be a game changer for the biologists involved. With scientists speculating that only one third of oceanic species have been discovered the ExoSuit might be exactly what scientists require to spur on future discovery.  Given the extreme conditions that exist within the deep ocean researchers might stumble upon morphologies that advance our understanding of design and engineering, along with a better understanding of bioluminescence.

During Casting


Monday, 3 March 2014

World's Largest Thermal Solar Plant Opens in California's Mojave Desert

A sea of 350,000 mirrors the size of garage doors is rippling across the Mojave Desert, reflecting solar energy onto 40-story towers and blazing a path for the growing solar industry as the world’s largest solar power plant of its type. The Ivanpah Solar Electric Generating Station, located along five square miles of federal land on the California-Nevada border southwest of Las Vegas, officially opened Thursday.



But the achievement for renewable energy has some downsides: Besides costing more per household than conventional coal or natural gas plants, it jostles a balance between clean-energy and harming wildlife and its habitat. The technology is killing birds with the scorching heat it bounces upward and threatens desert tortoises and bighorn sheep by tapping scarce water sources.

The $2.2 billion “power tower” solar-thermal plant, owned by NRG Energy Inc (NYSE:NRG), Google Inc. (NASDAQ:GOOG) and BrightSource Energy Inc., received a $1.6 billion federal loan guarantee. Mirror panels reflect sunlight onto boilers on three towers, heating water into steam that drives power generators to light up about 140,000 homes in a year and avoiding 400,000 metric tons of carbon dioxide per year, equal to removing 72,000 vehicles from the road.

Renault unveils Kwid concept car that comes with its own drone

Concept cars are great. They allow designers to play with ideas and forms that would never work in the real world. Take, for instance, the new Renault Kwid, the first Renault concept unveiled outside of Europe. It has a unique. design, with the driver in the middle of the front row, internal webbed seats, but most interestingly—a flying drone camera, all of its own.



The Kwid stores a mini drone in its roof, with the idea that it could be used to snap photos, help you park, check for accidents, keep an eye on traffic, and more. The Kwid was debuted at the Delhi Auto Show 2014, and is aimed at developing markets, such as India, and Brazil.

Here's the thing, this car will never be made. Not in its current form. It's designed to look like an off-roader, despite being two-door, and two-wheel drive. The bird's nest interior would be impossible to clean. And a drone that size simply wouldn't be able to keep up with a car zooming down the highway at full speed.

But given the fact that cars can now come with built-in rear cameras to make sure you're not going to back over anyone, and settings to parallel park for you, this is an interesting glimpse of mechanical engineering at what cars of the future might one day be able to do.

Physicist proposes a thermodynamic explanation for the origins of life

A 31-year-old researcher from MIT believes he's figured out the basic physics behind the origin and evolution of life in the universe, a provocative new theory of life that borrows heavily from 19th century science.



According to physicist Jeremy England, the origin and evolution of life are processes driven by the fundamental laws of nature — namely the Second Law of Thermodynamics (Details of this law can be found in book of Thermodynamics in Mechanical Engineering). He's come up with a formula showing how a group of atoms, when driven by an external source of energy (like the sun) and when surrounded by a heat bath (like the ocean or atmosphere), can sometimes restructure itself as a way to dissipate increasing rates of mechanical energy. "You start with a random clump of atoms, and if you shine light on it for long enough, it should not be so surprising that you get a plant," England was quoted in Quanta Magazine.

• Here's how Natalie Wolchover describes his work:

At the heart of England's idea is the second law of thermodynamics, also known as the law of increasing entropy or the "arrow of time." Hot things cool down, gas diffuses through air, eggs scramble but never spontaneously unscramble; in short, energy tends to disperse or spread out as time progresses. Entropy is a measure of this tendency, quantifying how dispersed the energy is among the particles in a system, and how diffuse those particles are throughout space. It increases as a simple matter of probability: There are more ways for energy to be spread out than for it to be concentrated. Thus, as particles in a system move around and interact, they will, through sheer chance, tend to adopt configurations in which the energy is spread out. Eventually, the system arrives at a state of maximum entropy called "thermodynamic equilibrium," in which energy is uniformly distributed. A cup of coffee and the room it sits in become the same temperature, for example. As long as the cup and the room are left alone, this process is irreversible. The coffee never spontaneously heats up again because the odds are overwhelmingly stacked against so much of the room's energy randoml concentrating in its atoms. Although entropy must increase over time in an isolated or "closed" system, an "open" system can keep its entropy low — that is, divide energy unevenly among its atoms — by greatly increasing the entropy of its surroundings. In his influential 1944 monograph "What Is Life?" the eminent quantum physicist Erwin Schrödinger argued that this is what living things must do. A plant, for example, absorbs extremely energetic sunlight, uses it to build sugars, and ejects infrared light, a much less concentrated form of energy. The overall entropy of the universe increases during photosynthesis as the sunlight dissipates, even as the plant prevents itself from decaying by maintaining an orderly internal structure...

...[England] derived a generalization of the second law of thermodynamics that holds for systems of particles with certain characteristics: The systems are strongly driven by an external energy source such as an electromagnetic wave, and they can dump heat into a surrounding bath. This class of systems includes all living things.

England then determined how such systems tend to evolve over time as they increase their irreversibility. "We can show very simply from the formula that the more likely evolutionary outcomes are going to be the ones that absorbed and dissipated more energy from the environment's external drives on the way to getting there," he said. The finding makes intuitive sense: Particles tend to dissipate more energy when they resonate with a driving force, or move in the direction it is pushing them, and they are more likely to move in that direction than any other at any given moment.

Artificial muscle made of fishing line is 100 times stronger than yours

By taking simple sewing thread and fishing wire and giving it a twist, scientists have created artificial muscle that's 100 times stronger than human or animal sinew. The invention, described in the journal Science, could be useful for prosthetic limbs, humanoid robots, implanted medical devices and even wearable clothing. This wouldn't be the first artificial muscle out there: there are carbon nanotube yarns and metal wires, but they're often expensive or store relatively low amounts of energy compared to their competitors, scientists said.



These new high-strength polymer fibers, made out of cheap, everyday materials that cost about $5 per kilogram, draw their strength from their geometry. In experiments led out of the University of Texas at Dallas in Richardson, scientists took these thin fibers that were just a few hundred micrometers long and twisted them until they began to coil. (You can see this same effect yourself if you take a rubber band and twist it until it starts to collapse into larger loops.) As it coils, the twisted fiber cable becomes shorter and thicker, and then the researchers heat-treated it to make it set. The scientists found that if they made the fiber coil in the same direction as the twist, the fiber cable would contract. If the fiber was forced to coil in the opposite direction of its twist, the fiber cable would expand.

When they applied an energy source to the fibers-typically heat-the scientists got different versions of their artificial muscle fibers to contract by 49 percent. or to expand by 67 percent. They even produce 7.1 horsepower per kilogram, about the same power as a jet engine (when scaled down for size). And the fibers can last through millions of these cycles, making them very durable, reusable devices.

"Despite their small diameter, the fibers can be indefinitely long and used in large structures," Jinkai Yuan and. Philippe Poulin, scientists from the. University of Bordeaux in France who. were not involved in the paper, wrote in a commentary.

The scientists think this could be useful for a number of applications that need muscle fibers , whether getting the. faces of humanoid robots to move with more human-like expressions or getting prosthetic limbs better muscle. They could be used to automatically open and shut blinds in response to the outside climate. The researchers already have created a textile with pores that expand and contract in response to heat-which could lead the way to adaptable, breathable clothing.

Peugeot to launch hybrid car that runs on air next year

Hold your breath! French car maker Peugeot is all set to sell the first air-powered hybrid car from next year. With new ‘Hybrid Air’ engine system – the first to combine petrol with compressed air – the firm says the car could reduce petrol bills by 80 percent when driven in cities. “Air power would be used solely for city driving, automatically activated below 43mph,” said Peugeot in a press release.




The system combines a gasoline engine with an air engine which is used at speeds under 70mph. This enables it to run on petrol or air, or a combination of both. According to the company, by 2020, the car could achieve an average of 117 miles a gallon.

The new engine system is a breakthrough for hybrid cars because expensive batteries would no longer be needed. Cars fitted with Hybrid Air system would be cheaper to buy than current hybrid models. Drivers never run the risk of running out of compressed air because the car would have a sophisticated device that ensures it replenishes itself automatically, added Peugeot.

Innovative


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