terça-feira, 25 de novembro de 2014

Gizmag recalls (2012) LiquidPiston 40-bhp X2 rotary engine with 75 percent thermal efficiency

 

The LiquidPiston X2 rotary engine boasts a thermal efficiency of 75 percent

The LiquidPiston X2 rotary engine boasts a thermal efficiency of 75 percent

OCTOBER,21,2012 by David Szondy

Image Gallery (10 images)

The internal combustion engine (ICE) has had a remarkably successful century and a half. Unfortunately, it’s notoriously inefficient, wasting anywhere from 30 to 99 percent of the energy it produces and spewing unburned fuel into the air. Last week, Gizmag interviewed Dr. Alexander Shkolnik, President and CEO of LiquidPiston, Inc. about the company's LiquidPiston X2 – a 40-bhp rotary engine that burns a variety of fuels and requires no valves, cooling systems, radiators or mufflers, yet promises a thermodynamic efficiency of 75 percent. (Update: The engine has a goal of achieving a 57 percent brake efficiency.)

Co-founder of LiquidPiston with his father Nikolay, Dr. Shkolnik believes that the internal combustion engine is at the end of its development cycle. According to Shkolnik, after 150 years the ICE has made as many incremental improvements as it can. Many varieties of ICE, such as the Otto cycle used by petrol engines and the Diesel cycle, have had their successful points, but all fall short of being as efficient at they could be. Even what seem like very efficient engines, like the diesel, aren't as good as they might appear.

The LiquidPiston X2 rotary engine and a comparable diesel engine

“Everyone would say at first glance that the diesel engine is more efficient (than the petrol engine). The truth is that if you had both engines at the same compression ratio, the spark-ignited engine has a faster combustion process and a more efficient process. In practice, it’s limited to a lower compression ratio otherwise you get spontaneous ignition.”

LiquidPiston’s approach to the problem was to go back to the basics of thermodynamics and work forward to develop what Shkolnik calls the “High Efficiency Hybrid Cycle” (HEHC), which combines the features of the Otto, Diesel, Rankine, and Atkinson cycles.

Comparison between the Wankel and X2 engine

The idea is to compress the air in the LiquidPiston X2 engine to a very high ratio as in the diesel cycle and then isolating it in a constant volume chamber. When fuel is injected, it’s allowed to mix with the air and it auto-ignites as in a diesel engine, but the fuel/air mixture isn’t allowed to expand. Instead, it’s kept compressed in a constant volume so it can burn over an extended period, as in the Otto cycle. When the burning fuel/air mix is allowed to expand, it’s then overexpanded to near-atmospheric pressure. In this way, all the fuel is burned and almost all of the energy released is captured as work. Shkolnik calls this use of constant volume combustion “the holy grail of automotive engineering.”

Constant volume combustion and overexpansion provide an HEHC engine like the X2 with a number of benefits. Shkolnik points out that the X2 engine is exceptionally quiet because it burns all of its fuel. In current ICE engines, an alarming amount of fuel goes out the tailpipe. This not only cuts down on fuel efficiency and pollutes the air, it also makes the engine noisy. Since the X2 engine burns its fuel completely, there’s no need for complicated silencing apparatus. (Update: The engine runs quietly due to not needing poppet valves.)

The LiquidPiston engine in operation

The overexpansion used in the cycle also means that there is very little waste heat. An ICE only converts only 30 percent of its heat into work while the X2 engine has a thermal efficiency of 75 percent, so a water cooling system isn’t necessary. Water may be injected into an HEHC engine during compression or expansion for cooling, but doing so also helps to lubricate and seal the chamber and as the water cools the engine it converts into superheated steam, which boosts engine efficiency.

Shkolnik says that the X2 engine is a rotary because piston engines aren’t suitable for the HEHC and a rotary engine provides much more flexibility. Also, the use of a rotary design greatly simplifies the engine with only three moving parts and 13 major components required. That allows the X2 to be one-tenth the size of a comparable diesel engine.

The LiquidPiston X2 rotary engine

When asked whether the X2 engine isn’t just an updated Wankel, Shkolnik pointed out that though both are rotary engines, the Wankel is very different. For one thing, it uses a straightforward Otto cycle like a piston engine and operates at a much lower compression rate than the X2. In comparison, the X2 engine is almost the opposite of a Wankel. “It’s almost like the Wankel engine flipped inside-out,” said Shkolnik.

Not only does the X2 engine work on a different principle from the Wankel, but it doesn't suffer from the same limitations. The X2 engine has a better surface to volume ratio, it doesn’t have the thermodynamic limitations of the Otto cycle and it doesn't have the emissions problems of the Wankel. The Wankel has apex seals that are carried around with the rotor and need to be lubricated. To do this, oil has to be sprayed on them, which means that the Wankel is burning oil as it runs, resulting in the high emissions that have recently curtailed its use. The X2 engine, on the other hand, moves the seals from the rotor to the housing, so no special lubrication is required.

Power curve of the HEHC cycle

Another way that the X2 engine differs from the Wankel is that Shkolnik has no intention of it sharing the same fate as the Wankel, which turned into an automotive also-ran when put head to head with the ICE or hybrid electrics to power motor cars, (though he admits that the X2 engine would be an excellent range extender for hybrids). Instead, he plans to go after niche markets that can use the X2’s peculiar strengths.

One place where the X2 engine may have an advantage is in auxiliary power units (APUs). Shkolnik said that an enormous amount of diesel fuel is wasted by lorry drivers for “hotel” purposes. That is, when they stop overnight they leave their engines idling to provide power for the living amenities of their long-distance rigs. Small, lightweight diesel power units with high fuel efficiency, he believes, would be particularly attractive.

Power curve of the HEHC cycle compared to the Otto and Diesel cycles

Another area is military applications. The U.S. military has a need for APUs that can run on heavy fuels, which the X2 engine can. Also, the Pentagon is very keen on developing robots. According to Shkolnik, “you can do amazing things with robots, but ask a robot to carry this giant engine and there’s problems.” He believes that the X2 engine may be the answer to these problems. In addition, the military has need of APUs for tanks, which suffer from extremely bad fuel efficiency from idling to run electronics.

Currently, LiquidPiston is running its original X1 engine in tests, which has been built after only a year from its first design concept. This month, the company unveiled the X2, which is a more fully integrated engine with a simpler construction, at the DEER Conference in Dearborn, Michigan. Shkolnik says that the X2 will be available for partner tests in 2013 as a new round of financing is launched and he hopes to have a preproduction prototype by 2014.

Source: LiquidPiston

Update:

The story has been modified in some places to clarify some technical points.

 

Michelin opens first plant dedicated to production of airless tires

 

Michelin has announced the opening of its newest North American plant, which it says is th...

Michelin has announced the opening of its newest North American plant, which it says is the first in the world dedicated to the manufacture of airless tires

Image Gallery (8 images)

A punctured tire is the definition of a bad day, but Michelin is taking some of the sting out as it announces the opening of its newest North American plant, which the company says is the first in the world dedicated to the manufacture of airless tires called "Tweels". The US$50 million plant will be used to make the Michelin X Tweel Airless Radial Tire and others for commercial and agricultural applications.

The Tweel is a combined tire and wheel that was introduced by Michelin as a concept in 2005. It consists of a molded-tread rubber band similar to that of a conventional tire mounted on a steel shear beam that acts as a contact patch. Between this and the hub is a series of energy-absorbing polyurethane spokes connected to an inner rim structure, which can be adjusted based on the expected loads with the tread also able to be customized.

According to Michelin, the Tweel lasts three times as long as conventional tires and has high lateral stiffness and low lateral stiffness, both of which can be adjusted independently. Unlike conventional tires, the tread can be replaced without having to replace the entire unit, so there is less waste of material. In addition, since the design doesn't need to retain air, it can be made to shed water quickly, which reduces hydroplaning. The company says that the Tweel is easy to install, damage resistant, and provides increased operator comfort.

Diagram of the Tweel

Currently, Michelin is aiming its advanced airless radial tire at the agricultural and construction markets, which suffer from significant downtimes from punctures. However, the performance of the Tweel indicates that it has applications in many other fields.

"Differentiating us from competitors, the Tweel airless radial tire is the industry’s first commercialized airless radial solution and verifies Michelin’s leadership for the next generation of mobility," says Ralph Dimenna, head of Michelin Tweel Technologies. "The Tweel airless radial tire enables Michelin to enter new markets and expand its reach in existing business segments within the low-speed application category. The industry is hungry for solutions contributing to productivity, safety and bottom lines."

 

Source: Michelin via The Telegraph

 

Guy Finds a Baby Squirrel On the Streets… What He Does Next is Beyond Amazing

 

This man was walking to work when he saw this little baby half dead on the ground in the Florida sun. He took her in but he had no idea what to do. He turned to the Internet for help, but he was told by others that he didn’t have enough experience to save her and ultimately, she would die. As it turns out, they were all wrong.

This man named this Southern flying squirrel Biscuits, and he found Biscuits baking in the Floridan sun. 
cool-baby-squirrel-hand-sick
Biscuits was so tiny, that the man had trouble telling what it was. 
cool-baby-squirrel-half-dead
The Internet told him that Biscuits would die for sure. 
cool-baby-squirrel-surviving-saving
But he refused to give up hope.
cool-baby-squirrel-little-head
And that was all Biscuit needed to survive. 
cool-baby-squirrel-fighting-life
He showed love and devotion to save Biscuit’s life.
cool-baby-squirrel-tiny-tail
Slowly, Biscuits opened her eyes  and took the man as her new daddy. 
cool-baby-squirrel-rehabilitating
She also became a rebellious at time, but she was still a sweetheart. 
cool-baby-squirrel-cute-nose
Her recovery is one of the cutest things. 
cool-baby-squirrel-resting-belly
She also made new friend’s with the man’s dog. 
cool-baby-squirrel-dog-smelling
They soon became the best of friends. 
cool-baby-squirrel-dog-friend
Guess, who just had dinner? 
cool-baby-squirrel-dirty-mouth
The man hand fed Biscuits for each meal, and Biscuits soon grew up to be big and strong. 
cool-baby-squirrel-feeding-milk
The man felt like Biscuits was always hungry.
cool-baby-squirrel-feeding-pocket
She was slowly turning into a beautiful flying squirrel.
cool-baby-squirrel-cute-eyes
He even taught her how to skateboard. 
cool-baby-squirrel-skateboarding
…and help with complex Excel calculations. 
cool-baby-squirrel-cute-love-devotion
He also learned how to sail the 7 seas. 
cool-baby-squirrel-sailor-hat
He loved staying in the man’s breast pocket. 
cool-baby-squirrel-inside-pocket
Just to think that everyone gave up on Biscuits except for this man.
cool-baby-squirrel-cute-owner
Now you wouldn’t have known that this squirrel was on the edge of survival. 
cool-baby-squirrel-cage-happy
This is biscuits and her daddy: best friends for life.
cool-baby-squirrel-cute-pocket-happy

It is amazing how a little hope can go a long way.

Source: The Meta Picture

Snap 2014-11-25 at 20.09.08

Physicists and chemists work to improve digital memory technology

 


 

The improvements in random access memory that have driven many advances of the digital age owe much to the innovative application of physics and chemistry at the atomic scale.

Accordingly, a team led by UNL researchers has employed a Nobel Prize-winning material and common household chemical to enhance the properties of a component primed for the next generation of high-speed, high-capacity RAM.

The team, which published its findings in the Nov. 24 edition of the journal Nature Communications, engineered and tested improvements in the performance of a memory structure known as a ferroelectric tunnel junction.

The junction features a ferroelectric layer 100,000 times thinner than a sheet of paper, so thin that electrons can "tunnel" through it. This layer resides between two electrodes that can reverse the direction of its polarization -- the alignment of positive and negative charges used to represent "0" and "1" in binary computing -- by applying electric voltage to it.

The researchers became the first to design a ferroelectric junction with electrodes made of graphene, a carbon material only one atom thick. While its extreme conductivity makes graphene especially suited for small-scale electronics, the authors' primary interest lay in how it accommodated nearly any type of molecule -- specifically, ammonia -- they placed between it and the ferroelectric layer.

A junction's polarity determines its resistance to tunneling current, with one direction allowing current to flow and the other strongly reducing it. The researchers found that their graphene-ammonia combination increased the disparity between these "on" and "off" conditions, a prized outcome that improves the reliability of RAM devices and allows them to read data without having to rewrite it.

"This is one of the most important differences between previous technology that has already been commercialized and this emergent ferroelectric technology," said Alexei Gruverman, a Charles Bessey Professor of physics who co-authored the study.

Ferroelectric materials naturally boast the quality of "non-volatility," meaning they maintain their polarization -- and can hence retain stored information -- even in the absence of an external power source. However, the infinitesimal space between the positive and negative charges in a tunnel junction makes maintaining this polarization especially difficult, Gruverman said.

"In all memory devices, there is a gradual relaxation, or decrease, of this polarization," he said. "The thinner the ferroelectric layer is, the more difficult it is to keep these polarization charges separate, as there is a stronger driving force in the material that tries to get rid of it."

Gruverman said the team's graphene-ammonia combination also shows promise for addressing this prevalent issue, significantly improving the stability of the junction's polarization during the study.

Gruverman's UNL co-authors included Haidong Lu and Dong Jik Kim, postdoctoral researchers in physics and astronomy; Alexey Lipatov, a postdoctoral researcher in chemistry; Evgeny Tsymbal, George Holmes University Professor of physics and astronomy; and Alexander Sinitskii, assistant professor of chemistry. The study was also authored by researchers from the University of Wisconsin-Madison and the Moscow-based Kurnakov Institute for General and Inorganic Chemistry.

The team's research was conducted with the assistance of UNL's Materials Research Science and Engineering Center -- part of a nationwide network of MRSECs sponsored by the National Science Foundation -- and also received support from the U.S. Department of Energy.


Story Source:

The above story is based on materials provided by University of Nebraska-Lincoln. The original article was written by Scott Schrage. Note: Materials may be edited for content and length.


Journal Reference:

  1. H. Lu, A. Lipatov, S. Ryu, D. J. Kim, H. Lee, M. Y. Zhuravlev, C. B. Eom, E. Y. Tsymbal, A. Sinitskii, A. Gruverman. Ferroelectric tunnel junctions with graphene electrodes. Nature Communications, 2014; 5: 5518 DOI: 10.1038/ncomms6518

 

These 32 Mineral Specimens Are Stunningly Beautiful

 

Snap 2014-11-25 at 18.19.19

Tree fossils with Opal growth rings

Source: etsy.com

Uvarovite

Source: flickr.com

Fluorite

Source: roywmacdonald.com

Kammererite

Source: exceptionalminerals.com

Hematite, Rutile, and Feldspar

Source: mindat.org

Torbernite (this one is radioactive)

Source: imgur.com

Clinoclase

Source: mindat.org

Vanadinite crystals on white Barite

Source: flickr.com

Fossilized egg? No it’s an Opal geode

Source: reddit.com

Blue Callaghanite on white Hydromagnesite

Source: mindat.org

Silver Stibnite with Barite

Source: wikimedia.org

Chalcanthite

Source: tumblr.com

Karpatite

Source: flickr.com

Cacoxenite

Source: scientificcomputing.com

Fluorite

Source: atlantisqueen.co

Labradorite

Source: carionmineraux.com

Black Opal

Source: reddit.com

Cuprosklodowskite (also radioactive)

Source: flickr.com

Blue Halite and Sylvite

Source: mindat.org

Fluorite

Source: reddit.com

Bismuth

Source: periodictable.com

Source: reddit.com

Tourmaline

Source: saphiraminerals.com

Bayldonite

Source: mindat.org

Osmium (the densest natural element)

Source: wikimedia.org

Malachite

Source: mindat.org

Emmonsite

Source: mindat.org

Aquamarine on Muscovite

Source: mindat.org

Pallasite Meteorite

Source: tumblr.com

Boleite

Source: tumblr.com

Crocoite

Source: awminerals.com