Material advantage: new metal matrix may cause marine engineers to switch

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Metal sea wreckage might be made to float

The development of a new metal matrix composite foam may tip the balance back towards metal materials in the construction of marine vehicles — in addition to offering heat resistance well beyond that of the fiberglasses common in the industry today. According to NYU engineers, the first lighter-than-water metal construction foam can withstand significant pressure and three times as much heat as fiberglass.

“This is the first time anybody has been able to achieve density of the composite lower than that of water to create naturally buoyant materials,” explained New York University Polytechnic School of Engineering’s Dr. Nikhil Gupta.

Dr. Nikhil Gupta
Dr. Nikhil Gupta

The metal matrix composite is a magnesium alloy reinforced with spherical silicon carbide particles. The density — 0.92 grams per cubic centimeter versus water’s 1.0 – still allows the material to withstand 25,000 pounds per square inch of pressure before rupturing.

Some of the strength of the material is due to the hallow particles embedded in the material, which absorb energy during a fracture. With different measures of spheres added to the matrix, various densities can be created.

“The spheres are manufactured by our industrial partner Deep Spring Technology, Toledo, OH, USA,” noted Gupta, an expert in mechanical and aerospace engineering.

GUP_3482Spheres were the shape of choice for the foam. “This company also has capabilities of manufacturing hollow particles of many other shapes,” said Gupta, who referred to two other types of particle shapes — made of silicon carbide [gray color] and alumina [white color].

GUP_3486 - Copy“Spherical particles have advantage that their properties are the same from any side. Particles of different shapes need to be used with more caution with regard to loading them along their strongest direction.”

The light-weight heat-resistant material is also expected to offer potential improvements in fuel economy for land transportation. The ability of metallic materials to withstand high temperatures is one of the main selling points, Gupta noted.

“Some of the competing materials are polymer matrix composites, commonly known as ‘fiberglass.’ One of the limitations of fiberglass materials is that they cannot be used over 150 degrees Celsius because polymer will degrade or burn. In addition, fire, smoke, and toxicity are concerns when polymers are exposed to high temperature. Magnesium and Magnesium matrix composites can be used up to about 500 degrees Celsius. Automotive components such as pistons, connecting rods, exhaust systems and structural components can be made of lightweight Mg matrix composite materials. High temperature in many of these components prohibits use of polymer matrix composites.

“The Magnesium-hollow sphere composites that we have developed also absorb a large amount of energy under compression. This property is desirable in automotive energy absorber components in cursing zones. These foams can also be filled in A and B-pillars of cars, and doors for side impact energy absorption.”

The technology may be put into use in prototype automobiles and boats within three years, as well as in amphibious vehicles developed by the US military, where currently the trend is toward other materials, although experts consider that the new lightweight product may again give metals a material advantage.

“Weight reduction in transportation applications can help in reducing the fuel consumption,” Gupta told us. “In addition, the high energy absorption capability per unit mass in these materials can also help in making vehicles safer. However, one material cannot be used to make all components, we need to find the components that will benefit the most from these new materials.

The report, “Dynamic Properties of Silicon Carbide Hollow Particle Filled Magnesium Alloy (AZ91D) Matrix Syntactic Foams,” was completed by Harish Anantharaman, Vasanth Chakravarthy Shunmugasamy, Oliver M. Strbik III, Nikhil Gupta and Kyu Cho, and was published in the International Journal of Impact Engineering.

By Sid Douglas

Possible new law of nature on the way

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The world of physics is excited about strong but early evidence about the behavior of muons, paricles identical to electrons only 200x more massive (heavier), which once born take 2.2 microseconds to decay into an electron, and which spin like tops. In a new, extremely precise measurement, they were made to wobble using magnetic fields but they unexpectedly wobbled quite significantly faster than the Standard Model suggests they would. They might spin so fast due to an unknown force caused by an unknown particle, and this is what is so exciting.

“We found that a muon … is not in agreement with our current best theory of physics at the subatomic level, and … it potentially points to a future with new laws, new particles and new forces in physics which we haven’t seen to date,” said Professor Mark Lancaster at U of Manchester.

“The main goal of the experiment is to make the measurement and compare with the theory, and if they disagree then it’s telling us that there’s something in nature which is not in the theory,” explained James Mott at Fermilab.

The four known forces of nature (gravity, electricity, two nuclear forces: strong and weak interactions) have left scientists without an answer for some observed phenomena, such as the speed at which galaxies spin (faster than the best model suggests). Therefore, they continue to search for glitches in their already-tight models which might point them things they don’t yet know about.

The most recent work was done at Fermilab (Muon g-2 experiment), but a similar experiment was already done earlier at the Large Hadron Collider. These tools accelerate particles in large rings at close to the speed of light.

The evidence needs more tests for greater certainty, particularly to rule out the possibility of a systematic error, and particularly with a new, independent experiment, but physicists will be chasing this line of experiment eagerly.

“This is outstanding confirmation of experimental technique, and very, very suggestive of the possibility of new physics,” noted scientist David Hertzon of U of Washington.

By the editors

#AnomalousMagneticDipoleMomentOfTheMuon #QuantumElectrodynamics

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People in Kachin state demonstrate against China

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YANGON, Myanmar – The people in the Pharkant area of Kachin state demonstrated against China this week, drawing a cross on the Chinese flag and burning a picture of Myanmar’s military leader Min Aung Hlaing.

“China stands with the military leader,” shouted the demonstrators.

By Htay Win
Photo credit Aye Yarwaddy

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Myanmar military council arrests the artist Zarganar

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YANGON, Myanmar – The artist Zarganar was arrested by the Myanmar military council from his home in Tarmwe township, Yangon this morning.

Zarganar is not only a director but also a comedian famous for political jokes since the 1988 democratic revolution.

Zarganar was arrested by the Myanmar military many times before 2010.

By Htay Win
Photo credit Zarganar page

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Kayin IDPs struggle to get for food

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YANGON, Myanmar – Kayin internally displaced people are desperate for food, clothing and shelter, hiding in the forest from the air strikes of the Myanmar military.

The IDPs fled to neighboring Thailand, but Thai government turned them back. However, Wednesday morning the Thai government opened Maeseli jetty in Maehaungsaung district to sending rations and medicines over the border to Kayin state, according to a Thai media.

By Htay Win

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Twenty Myanmar celebrities charged with incitement

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YANGON, Myanmar -They were charged under the country’s media law with inciting government employees to join the popular civil disobedience movement (CDM) through social media.

Celebrities took part in the NLD election campaigns and are thought to have played a large part in influencing the public, particularly Myanmar’s youth, to vote for Aung San Suu Kyi.

By Htay Win
Photo credit Myanmar celebrity

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