research (86)

Beneficent Adversaries...

Petty Officer Third Class Robert H. Goodwin, WWII veteran

Topics: Nanofluidics, Nanotechnology, Research, STEM, Thesis

I passed my Thesis defense in Monday. I have a Masters in Nanoengineering.

After many weeks of running experiments, parsing data and writing preliminary conclusions, I had to stand before my committee: my advisor (chemist) and my nano physics professor, the department chair (mechanical engineering) and defend my research. In hindsight, it was the committee on steroids.

I bought coffee and donuts; water for the committee as is the tradition. That exposed me to 95 degree heat and North Carolina humidity. I ended up defending without my suit jacket.

There is the public defense part where you get questions from either the panel or the audience. Then the grueling begins when the audience is encouraged to leave and you are alone with your committee.

I was challenged on my understanding of the data, not in an accusatory way but to foster a better rewrite when I turn in my written product to the Graduate College. Those are due next Wednesday. I should be able to fulfill that request on review with my advisor. The committee also suggested further experiments I could do to verify what I thought I was seeing. After an intense 40 minutes of questioning, I was asked to leave as the committee conferred. For what seemed like an eternity, my advisor came out and shook my hand: "congratulations." I then went in to the committee to get their final suggestions and signatures for completing the process.

I am also moving...within Greensboro mind you, but to a house we own outright versus a rental apartment we don't.

It reminded me of my father proudly burning the last payment record as we owned our modest home - two bedrooms, one bath and less than a thousand square feet - in East Winston-Salem off Cleveland Avenue.

For the move, I had to parse through memorabilia that traveled with us from Texas to New York to North Carolina. It was time to make some decisions.

I found the program and invitation to my mother's graduation from Practical Nursing School in Philadelphia, Pennsylvania. I imagined the trip for her and my father probably took a lot of back roads and the Green Book during that time period.

I found my parents' invitations sent for my high school graduation as well as my acceptance letter saying I had been accepted to North Carolina A&T State University for the fall semester, 1980. I found my first karate promotion certificates from Dr. Casterlow as part of the A&T Dojo.

I found a short story my father kept I had written for catharsis called "The Decision." It was when Pop left it to me to decide the fate of my dog, a Cocker Spaniel named Fala, named after FDR's dog. He was aged, tired and had stopped eating. The gist of the story was "sometimes as a man, you have to make difficult decisions." I was twelve. I didn't own a dog again until I was an adult with sons of my own. Parting with each four-legged friend has never gotten easier.

I found a lot of family photos that will go in albums and on a flash drive soon.

I also found the corroborating evidence I had read on the GI Bill like the New Deal before it was discriminatory to African Americans. My father passed a college entrance exam with only a sixth grade education formally, due to the fact he and my uncle Moses, Jr. went to work for my grandmother to help out the household. The GI Bill for white soldiers and sailors paid for a college education and loans encouraging home ownership, building a wealth gap that has persisted for generations. Many white service members went on to become professionals and professors. The GI Bill for my father and his fellow WWII veterans of color only covered vocational training, like barber school. So that's what he learned. Pop often cut my hair in the kitchen of our home  in a segregated neighborhood crafted by redlining legislation. He faced the indignities of working for a textile company - routinely getting passed over for promotions and getting called "boy" or n-word then his name. He smoked in a chair in his bedroom before he engaged with the family every evening after work. That was his way of coping. It eventually led to lung cancer, the contributing cause of his death.

I sadly had to throw away his literature books he bought for me: I read The Iliad and the Odyssey from that collection. I read snippets of Milton and I meant to read Thomas Paine. They alas were molded and mildewed; unrecoverable. I plan to replace the collection once we're settled in.

Announcing the good news on Facebook numbered in the thousands on the Kappa Alpha Psi page; hundreds on my main feed. It was good to see others, near and far, celebrate this achievement with me.

I passed my Masters Thesis defense.

I like to think I redeemed my father's dreams as well.
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Ionic Clock...

Physics World: A brief history of timekeeping

Topics: Atomic Physics, Laser, NIST, Quantum Mechanics, Research

By confining single ions of aluminum and magnesium in an electric trap, cooling them to near absolute zero and probing them with laser beams, physicists at the National Institute of Standards and Technology (NIST) in Boulder, Colorado have built what is in effect the world’s most accurate clock. Having fractionally improved on the performance of another clock at NIST, the researchers have shown that their device would neither gain nor lose a second in 33 billion years (if it could run for that long). Such accurate timekeeping, they say, could boost geodesy and lead to new insights in fundamental physics.

The clocks that currently underpin atomic time rely on precisely measuring the frequency of microwaves emitted during a specific transition in cesium atoms. But such devices are limited by the relatively low frequency of that radiation. To keep time even more accurately, and eventually introduce a new definition of the second, physicists are developing clocks based on higher-frequency optical transitions.

The latest work at NIST features what is known as a quantum-logic clock. Built by Samuel Brewer and colleagues, it uses a positive ion of aluminum-27 as its timekeeper. When exposed to ultraviolet laser light at wavelength 267 nm, the ion undergoes a transition with a very narrow line width – making its frequency very well defined. What is more, that transition is largely immune to sources of external noise – such as blackbody radiation – that in other types of optical clock shift the frequency away from its true value.

A magnesium-25 ion is used to cool the aluminum down to the very low temperatures needed to minimize thermal noise. Cooling involves the absorption of photons at another specific frequency, but practical limitations mean that this cannot be done using the aluminum itself. This is because the required frequency in is too high for any practical laser. By entangling the two ions, the magnesium cools the aluminum via Coulomb interactions. This process also allows the quantum state of the aluminum ion to be read-out following exposure to the clock laser.


Entangled aluminum ion is world’s best timekeeper, Edwin Cartlidge, Physics World

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Sonic Tractor Beam...

Sound image: the acoustophoretic display reproduces the logo of the University of Bristol. (Courtesy: A Marzo, B Drinkwater and colleagues)


Topics: Acoustic Physics, Holograms, Research, Star Trek

A midair visual display that uses a single acoustically-levitated particle has been unveiled by researchers in Spain and the UK. Dubbed an “acoustophoretic display”, the image is created by using two ultrasound transducer arrays to levitate the particle and manipulate it to trace out the desired graphic at high speed.

In 2015, Asier Marzo at the Public University of Navarra and Bruce Drinkwater at the University of Bristol created a sonic tractor beam that used ultrasound to levitate, rotate and move objects. Using a single grid of 64 off-the-shelf loudspeakers controlled by a programmable array of transducers the device created 3D fields of sound – acoustic holograms – that could hold and manipulate a small polystyrene particle in mid-air.

Since then, the field has progressed and earlier this year Marzo and Drinkwater revealed an acoustic levitation device that used two grids of speakers to hold and individually manipulate up to 25 polystyrene balls at the same time. This opened up the possibility of new applications for sonic tractor beams, including visual displays created with multiple levitated particles.

According to Marzo, such acoustic generated images, which he calls acoustophoretic displays, would offer an advantage over current holograms as they would not suffer from clipping. “[With holograms] the image can only be viewed from determinate angles and the frame of the display occludes the image, it is like looking inside a window,” he explains. “With the acoustophoretic displays the images reside in the physical space and can be observed without clipping from 360°.”

Ultrasound guides particle in a midair display, Michael Allen, Physics World

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Peekaboo Parts...

A transparent human brain by Dr. Ali Ertuerk, Munich, Germany, April 23, 2019.


Topics: 3D Printing, Biomedicine, Research

MUNICH (Reuters) - Researchers in Germany have created transparent human organs using a new technology that could pave the way to print three-dimensional body parts such as kidneys for transplants.

Scientists led by Ali Ertuerk at Ludwig Maximilians University in Munich have developed a technique that uses a solvent to make organs such as the brain and kidneys transparent.

The organ is then scanned by lasers in a microscope that allows researchers to capture the entire structure, including the blood vessels and every single cell in its specific location.

Using this blueprint, researchers print out the scaffold of the organ. They then load the 3D printer with stem cells which act as “ink” and are injected into the correct position making the organ functional.

German scientists create see-through human organs, Ayhan Uyanik, Reuters

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Good Vibes...

Sounding off: theoretical force patterns for an underwater Chladni plate at two different frequencies. The force arrows illustrate why glass beads accumulate at the plate antinodes (shown in yellow and red). (Courtesy: K Latifi, H Wijaya and Q Zhou/Physical Review Letters)


Topics: Acoustic Physics, Applied Physics, Research

The behaviour of some particles on the vibrating surfaces of Chladni plates is reversed underwater, a new study reveals. The discovery was made by Kourosh Latifi, Harri Wijaya, and Quan Zhou at Aalto University in Finland. They observed that glass beads on a submerged vibrating plate move towards antinodes, where the plate’s amplitude of vibration is highest. The underwater effect could be useful in a variety of medical and biological applications, including the manipulation of living cells.

In 1787 the German physicist Ernst Chladni put sand on a vibrating plate and observed that the grains settle on the nodal lines where the plate’s amplitude of vibration is zero. In contrast, he observed that finer particles move towards the plate’s antinodes where the amplitude is a local maximum.

A century later, Michael Faraday explained both behaviours. He concluded that the vibrations cause the larger grains to move laterally across the plate until they reach a node – where they no longer get lateral kicks and therefore remain in place. As for why the smaller particles did the opposite, Faraday argued that air currents just above the plates tend to push the lighter particles towards the antinodes – an effect known as acoustic streaming.


Vibrations guide tiny glass beads through an underwater maze
Sam Jarman, Physics World

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Distant Cousins...

Callao Cave, Luzon Island, The Philippines

Image credits:
Callao Cave Archaeology Project


Topics: Biology, DNA, Evolution, History, Research

(Inside Science) -- In a jungle cave in the Philippines, scientists have discovered fossils of what may be a new human species they call Homo luzonensis. The newfound teeth and bones combine primitive and modern traits in a way never previously seen together in one species, and suggest much remains to be discovered about human evolution outside Africa.
Image Source: Homo luzonensis

Although modern humans, Homo sapiens, are now the only surviving branch of the genus Homo, other species of humans once roamed across Earth. For example, previous research suggested Homo erectus, the most likely ancestor of modern humans, made its way out of Africa by at least 1.8 million years ago. In contrast, modern humans may have only begun dispersing from Africa roughly 200,000 years ago.

Fifteen years ago, scientists revealed an unusual extinct human species from the Indonesian island of Flores -- Homo floresiensis, often called "the hobbit" due to its diminutive size, which lived on Earth during the same time as modern humans. This finding hinted that other hominins -- any relatives of modern humans dating from after our ancestors split from those of chimpanzees -- might await discovery in Southeast Asia.

Researchers Find a New Ancient Human Species in the Philippines
Charles Q. Choi, Live Science

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