#BNNT

[starzec]

BNNT, December 2023

[spacetimewithstuartgary]

Space travel: Protection from cosmic radiation with boron nitride nanotube fibers

With the success of the Nuri launch last year and the recent launch of the newly established Korea Aerospace Administration, interest in space has increased, and both the public and private sectors are actively investing in space-related industries such as space travel. However, exposure to cosmic radiation is unavoidable when traveling to space.

A research team led by Dr. Dae-Yoon Kim from the Center for Functional Composite Materials at the Korea Institute of Science and Technology (KIST) has developed a new composite fiber that can effectively block neutrons in space radiation. The work is published in the journal Advanced Fiber Materials.

Neutrons in space radiation negatively affect life activities and cause electronic devices to malfunction, posing a major threat to long-term space missions.

By controlling the interaction between one-dimensional nanomaterials, boron nitride nanotubes (BNNTs), and aramid polymers, the team developed a technique to perfectly blend the two difficult-to-mix materials. Based on this stabilized mixed solution, they produced lightweight, flexible, continuous fibers that do not burn at temperatures up to 500°C.

BNNTs have a similar structure to carbon nanotubes (CNTs), but because they contain a large number of boron in the lattice structure, their neutron absorption capacity is about 200,000 times higher than that of CNTs. Therefore, if the developed BNNT composite fibers are made into fabrics of the desired shape and size, they can be applied as a good material that can effectively block radiation neutron transmission.

This means that BNNT composite fibers can be applied to the clothing we wear every day, effectively protecting flight crews, health care workers, power plant workers, and others who may be easily exposed to radiation.

In addition, the ceramic nature of BNNTs makes them highly heat-resistant, so they can be used in extreme environments. Therefore, it can be used not only for space applications but also for defense and firefighting.

"By applying the functional textiles we have developed to the clothing we wear every day, we can easily create a minimum safety device for neutron exposure," said Dr. Dae-Yoon Kim of KIST.

"As Korea is developing very rapidly in the space and defense fields, we believe it will have great synergy."

TOP IMAGE: Applications of BNNT-based functional fabrics / The BNNT-based composite fibers can be manufactured into fabrics of various shapes and sizes through weaving. The developed fabrics can be utilized in clothing to protect astronauts, crew members, soldiers, firefighters, health care workers, and power plant workers who are expected to be exposed to radiation. The fabric can also be applied to electronic device packaging to prevent soft errors. Credit: Korea Institute of Science and Technology

CENTRE IMAGE: Development of BNNT composite functional fibers for space radiation shielding / If continuous composite fibers containing high content of BNNTs are used as functional fabrics, they can effectively shield neutrons in space radiation to reduce harmful effects on human health and prevent soft errors in electronic devices. These functional fabrics are expected to play an important role in the fields of aviation, space, and national defense. Credit: Korea Institute of Science and Technology

LOWER IMAGE: Development of BNNT composite continuous fibers / By overcoming the low dispersibility of BNNTs through interaction with aramid polymers, stable composite solutions can be prepared. This paves the way for the development of composite fibers that take advantage of the excellent properties of BNNTs and can be effectively utilized in various applications. Credit: Korea Institute of Science and Technology

[materialsscienceandengineering]

In nanotube science, is boron nitride the new carbon?

A technique for synthesizing many “white graphene” nanotubes at a time paves the way for stronger, heat-resistant composites, and membranes for renewable energy.

Engineers at MIT and the University of Tokyo have produced centimeter-scale structures, large enough for the eye to see, that are packed with hundreds of billions of hollow aligned fibers, or nanotubes, made from hexagonal boron nitride.

Hexagonal boron nitride, or hBN, is a single-atom-thin material that has been coined “white graphene” for its transparent appearance and its similarity to carbon-based graphene in molecular structure and strength. It can also withstand higher temperatures than graphene, and is electrically insulating, rather than conductive. When hBN is rolled into nanometer-scale tubes, or nanotubes, its exceptional properties are significantly enhanced.

The team’s results, published today in the journal ACS Nano, provide a route toward fabricating aligned boron nitride nanotubes (A-BNNTs) in bulk. The researchers plan to harness the technique to fabricate bulk-scale arrays of these nanotubes, which can then be combined with other materials to make stronger, more heat-resistant composites, for instance to shield space structures and hypersonic aircraft.

Read more.

[mixellr]

Check out this listing I just added to my Poshmark closet: KEDS RIFLE PAPER PRINT ANKLE SUEDE SNEAKERS.

[fowardfashionfindz]

Check out this listing I just added to my Poshmark closet: All in motion sports bra - tried on never worn (BNNT) - a favorite.

[kunstarmy]

#amazing #performance #music #noise #improvisation #drumming #tribal #rooted #post #energy #art #warsaw #bnnt @ninateka_pl

[anthologiealeatoire]

[TEASER] L'Aléatoire de janvier 2018

[if-you-fan-a-fire]

February 16, 2019: a new episode of The Anatomy Lesson at 11pm EST on CFRC 101.9 FM. Word salad. Music by Matteo Valliceli, Spa Moans, Wetware, Circa Tapes, Braeyden Jae, @tei-mei, Wetware, Lily Konigsberg & Ulysses + more. Tune in at 101.9 on your FM dial, stream at http://audio.cfrc.ca:8000/listen.pls or listen to the finished show on cfrc.ca or an archive here: https://www.mixcloud.com/cameronwillis1232/the-anatomy-lesson-february-16-2019/

Braeyden Jae - “Brutal Joy” False Flags (2018) Michael Beharie & Teddy Rankin-Parker - “Fake Money” A Heart From Your Shadow (2018) Meitei 冥丁 - “Sankai 山怪” Kwaidan 怪談 (2018) Gohan - “Beauté Accidentelle” Peur (2012) Circa Tapes - “Locks and Guts” Love and Venom (2017) Matteo Vallicelli - “Futuro” Primo (2017) Wetware - “The Luxury of Declining” Automatic Drawing (2018) Potter Natalizia Zen - “Unsystematic Waves” Shut Your Eyes on the Way Out (2018) ubik mcdxcii - “Ocean / Forest Son” Echoes of a Dead Planet (2017) Spa Moans - “Throat” Obedient Vibrations (2017) Lily Konigsberg & Ulysses - “I Can’t Stop Feeling So Good” Borglin (2015) Zos Kia / Coil - “Truth” Transparent (1984) BNNT - “Sickness Begins When One Begins To Think” Multiverse (2017)

[starzec]

BNNT @ Pogłos, 2020

[koffeina]

http://www.bnnt.pl http://moonmadness.eu/bnnt/

[smithm3]

[literallymechanical]

How do you test the purity/look for structural defects in CNTs? SEM?

Short answer: Yes, among other things.

Long answer: Carbon nanotubes (CNT's) are long, straight tubes of pure carbon, with the atoms arranged like rolled-up sheets of hexagonal chicken wire. Sometimes an atom or two will be misplaced, introducing a defect. The easiest kind of defect to visualize is a kink, like this:

(Source)

This is an AFM (atomic force microscope) image of a nanotube on a glass wafer, placed across four gold electrodes. That sharp kink in the tube is a weak spot.

(Side note: you can tell it's an AFM image because it's got really chunky raster lines. AFM's are fun. You drag an atomically-sharp diamond needle across a surface and measure the needle deflection with a laser. You can get the resolution down to less than a nanometer, if you hold your breath. I once spent a summer internship doing nothing but poking at graphene in an AFM for two months. Very repetitive work, but I got two publications out of it!)

However, it's rarely useful to look at individual CNT's outside of pure research. I worked with nanotube yarn in large-scale production. Large, twisted bundles of tubes, similar to this:

(Source)

This is an SEM (scanning electron microscope) image of high-quality nanotube yarn. Each of those thin whispy strands is probably a couple hundred nanotubes, and the entire structure is twisted smoothly together out of hundreds of thousands. At this point, you're less interested in the quality of individual tubes and more interested in the bulk properties of the yarn itself.

So, once you've verified it visually by SEM, the easiest way to characterize the strength of your nanotube yarn is to pull on it until it breaks.

(Source: High-strength carbon nanotube fibers by twist-induced self-strengthening)

This is a thick ribbon of compressed CNTs, twisted into a chunky pseudo-yarn. The graph shows that the fiber snapped at around 3.7 gigapascals of stress. That's five or six times stronger than steel, and four-ish times stronger than spider silk. Boron nitride nanotubes (BNNT) would be stronger, but that's a post for another day.

Anyway, this might seem impressive, but tbh those are rookie numbers. Twisted-ribbon "yarn" is a cheap and easy way to make strong nanotube fibers, but not nearly as good as a true yarn.

Don't tell the authors I said that.

The other point you brought up is testing for purity.

(source)

This picture is about twenty years old, back when we really had no idea what we were doing. By modern standards, this is hideously embarrassing. It's covered in blobs of leftover iron catalyst. It's an ugly garbage nanotube.

Don't tell the authors I said that.

There can be all sorts of contaminants. Bits of catalyst (usually iron or nickel) random ceramic or metal junk from your furnace, even leftover acid (chlorosulfonic acid is one of the only things that will un-stick carbon nanotubes, though it's an extremely bad chemical that hates you). It's always important to characterize how much nanotube is in your nanotubes.

Handily enough, the best way to test for purity is with the same electron microscope!

One effect of sweeping an electron beam across a target is that the target will emit x-rays as its electrons jump around. These x-rays are extremely predictable, and will have an energy that directly corresponds to the atom that produced them. So assuming that your SEM also has the right kind of x-ray sensor, you click a button and switch over the EDX mode, energy-dispersive X-ray spectroscopy.

(source)

This EDX graph shows high concentrations of iron (Fe), oxygen, and carbon in the sample (the silicon is likely from a glass mounting slide). If this were a bunch of CNT's, you'd hope to see almost entirely carbon, with maybe a little bit of iron or nickel. Uh oh!

Happily, this isn't nanotubes.

(source)

It's Rimicaris exoculata, a deep-sea shrimp that lives on hydrothermal vents and builds itself a little shell of iron oxide. Isn't that fun?

[mixellr]

Check out this listing I just added to my Poshmark closet: KEDS RIFLE PAPER PRINT ANKLE SUEDE SNEAKERS.

[haropro-confessions]

Busu ni Naranai Tetsugaku is my favorite all-H!P single. All for One & One for All was okay and YEAH YEAH YEAH is a boring unison ballad, but Busu ni Naranai Tetsugaku is a slammer and Kacchoi Uta is fun af. In 5-6 years when they make another all-H!P single I hope it's jazzy and unique with amazing solo/duets like BnNT has.