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

When political parties reverse their policy stance, their supporters immediately switch their opinions too

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At least a significant portion of their supporters, according to U of Aarhus researchers.

When two competing political parties in Denmark reversed their policy stance on an issue — suddenly they both supported reducing unemployment benefits — their voters immediately moved their opinions by around 15% into line with their party.

The same thing happened when one of these parties shifted from opposing to supporting ending Denmark’s early retirement.

The researchers were studying how public opinion is formed. Their recent paper sheds light on how much influence political parties have over their supporters, according to the researchers, who surveyed their panel of subjects in five successive waves between 2010 and 2011. They studied the same group of party supporters before, during and after a policy reversal.

“We can see that [the] welfare programs were actually quite popular … and many of the voters of the center-right party were in favor of these welfare programs,” commented one of the researchers, Rune Slothuus. “Nevertheless, we can see that they reversed their opinion from supporting these welfare programs to opposing these welfare programs.”

“I was surprised to see the parties appeared this powerful in shaping opinions,” Slothuus said. “Our findings suggest that partisan leaders can indeed lead citizens’ opinions in the real world, even in situations where the stakes are real and the economic consequences tangible.”

The researchers pondered Western democracy in light of their findings: “If citizens just blindly follow their party without thinking much about it, that should lead to some concern about the mechanisms in our democracy. Because how can partisan elites represent citizens’ views if the views of citizens are shaped by the very same elites who are supposed to represent them?”

Source: How Political Parties Shape Public Opinion in the Real World. Rune Slothuus and Martin Bisgaard. First published: 04 November 2020 https://doi.org/10.1111/ajps.12550

The brain listens for things it is trying to predict

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The brain interprets sounds as they contrast with its expectations; it recognizes patterns of sounds faster when they’re in line with what it is predicting it will hear, but it only encodes sounds when they contrast with expectations, according to Technische U researchers.

The researchers showed this by monitoring the two principal nuclei of the subcortical pathway responsible for auditory processing: the inferior colliculus and the medial geniculate body, as their subjects listened to patterns of sounds which the researches modified so that sometimes they would hear an expected sound pattern, and other times something unexpected.

Source: Alejandro Tabas, Glad Mihai, Stefan Kiebel, Robert Trampel, Katharina von Kriegstein. Abstract rules drive adaptation in the subcortical sensory pathway. eLife, 2020; 9 DOI: 10.7554/eLife.64501

We have a particular way of understanding a room

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When several research subjects were instructed to explore an empty room, and when they were instead seated in a chair and watched someone else explore the room, their brain waves followed a certain pattern, as recorded by a backpack hooked up to record their brain waves, eye movements, and paths. It didn’t matter if they were walking or watching someone else, according to UC researchers led by Dr Matthias Stangl.

The researchers also tested what happened when subjects searched for a hidden spot, or watched someone else do so, and found that brain waves flowed more strongly when they had a goal and hunted for something.

Source: Matthias Stangl, Uros Topalovic, Cory S. Inman, Sonja Hiller, Diane Villaroman, Zahra M. Aghajan, Leonardo Christov-Moore, Nicholas R. Hasulak, Vikram R. Rao, Casey H. Halpern, Dawn Eliashiv, Itzhak Fried, Nanthia Suthana. Boundary-anchored neural mechanisms of location-encoding for self and others. Nature, 2020; DOI: 10.1038/s41586-020-03073-y

Extroverts and introverts use different vocabularies

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Extroverts use ‘positive emotion’ and ‘social process’ words more often than introverts, according to new research conducted at Nanyang Technological U.

‘Love,’ ‘happy,’ and ‘blessed’ indicate pleasant emotions, and ‘beautiful’ and ‘nice’ indicate positivity or optimism, and are among the words found to be used more often by extroverts. So too are ‘meet,’ ‘share,’ and ‘talk,’ which are about socializing. Extroverts use personal pronouns — except ‘I’ — more too, another indication of sociability.

The correlation, however, was small, and the researchers think that stronger linguistic indicators need to be found to achieve their general goal, which is improving machine learning approaches to targeting consumer marketing.

Source: Jiayu Chen, Lin Qiu, Moon-Ho Ringo Ho. A meta-analysis of linguistic markers of extraversion: Positive emotion and social process words. Journal of Research in Personality, 2020; 89: 104035 DOI: 10.1016/j.jrp.2020.104035

WhatsApp is changing today - Users must give the app permission to send their private data to Facebook or lose account

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WhatsApp was bought by Facebook in 2014, but has thrived while promoting itself as a privacy-respecting messaging app that now has 1.5b monthly active users. This week, though, WhatApp sent out an update to users’ phones that they must ‘consent’ to a new policy or lose access.

Whatsapp will now share more of your data, including your IP address (your location) and phone number, your account registration information, your transaction data, and service-related data, interactions on WhatsApp, and other data collected based on your consent, with Facebook’s other companies. Facebook has been working towards more closely integrating Facebook, WhatsApp, Instagram and Messenger.

Users who do not agree to ‘consent’ to the new policy will see their WhatsApp account become inaccessible until they do ‘consent.’ These accounts will remain dormant for 120 days after which they will be ‘deleted.’

The biggest change to the user policy, which many people ignored and clicked ‘agree’ to, thinking it was just another unimportant app update message, now reads,

‘We collect information about your activity on our Services, like service-related, diagnostic, and performance information. This includes information about your activity (including how you use our Services, your Services settings, how you interact with others using our Services (including when you interact with a business), and the time, frequency, and duration of your activities and interactions), log files, and diagnostic, crash, website, and performance logs and reports. This also includes information about when you registered to use our Services; the features you use like our messaging, calling, Status, groups (including group name, group picture, group description), payments or business features; profile photo, “about” information; whether you are online, when you last used our Services (your “last seen”); and when you last updated your “about” information.’

Notably, Elon Musk tweeted on the news, saying that WhatsApp users should switch to Signal, one of several popular privacy-focused messaging apps similar to WhatsApp.

The data sharing policy change doesn’t affect people in Europe due to GDPR data protection regulations.