Manufacturing Bits: Aug. 13

Exascale supercomputers; gold nanosheets; gold glue.


Exascale supercomputers
The Department of Energy’s National Nuclear Security Administration (DOE/NNSA) has signed a contract valued at $600 million with Cray to build NNSA’s first exascale supercomputer.

The system, called El Capitan, is expected to be shipped in late 2022. El Capitan will be housed at Lawrence Livermore National Laboratory (LLNL), and will perform research to maintain the U.S. nuclear weapons stockpile.

It will achieve a sustained performance of more than 1.5 exaFLOPS, or 1.5 quintillion calculations per second, and substantially outpace LLNL’s Sierra system, which is currently the world’s second most powerful supercomputer at 125 petaFLOPS of peak performance.

El Capitan will be DOE’s third exascale-class supercomputer, following Argonne National Laboratory’s “Aurora” and Oak Ridge National Laboratory’s “Frontier” system. All three DOE exascale supercomputers will be built by Cray utilizing their Shasta architecture, Slingshot interconnect, and new system software platform

Recently, Hewlett Packard Enterprise agreed to acquire Cray for $35 a share in cash, with the transaction valued at about $1.3 billion, net of cash. The proposed merger would add supercomputing system technology to HPE’s product portfolio, expanding its offerings in high-performance computing (HPC).

Cray also announced a new, open and extensible software platform to address the growing need for supercomputing across government and private industries.

Thin gold nanosheets
The University of Leeds has developed what researchers say are the world’s thinnest gold nanosheets.

Using a new process, researchers have synthesized gold nanosheets with a thickness of only 0.47nm, which is just two atomic layers thick. The technology could one day be used for medical devices, electronics and catalysts. The process could also enable other types of materials.

Gold nanosheets are synthesized using a one‐step aqueous approach. First, researchers placed a chemical called methyl orange in a small glass beaker. The chemical is used as a confining agent.

Then, two aqueous solutions are sequentially mixed into the methyl orange solution at 20 °C. The solution was kept undisturbed for 12 hours, according to researchers. Then, it underwent a centrifugation process. The samples were washed several times.

This electron microscope picture shows the gold atoms’ lattice structure (Source: University of Leeds)

The resulting products transformed into thin gold nanosheets. “Gold is a highly effective catalyst. Because the nanosheets are so thin, just about every gold atom plays a part in the catalysis. It means the process is highly efficient,” said Stephen Evans, a professor of Leeds’ Molecular and Nanoscale Research Group. “Our data suggests that industry could get the same effect from using a smaller amount of gold, and this has economic advantages when you are talking about a precious metal.

“I think with 2D gold we have got some very definite ideas about where it could be used, particularly in catalytic reactions and enzymatic reactions. We know it will be more effective than existing technologies – so we have something that we believe people will be interested in developing with us,” Evans added.

Molecular nanocages
The Institute of Nuclear Physics of the Polish Academy of Sciences has developed new and complex molecular nanocages using gold glue.

Molecular nanocages are hollow and porous nanoparticles. They range in size from 10nm to over 150nm. Nanocages are used in various applications. For example, gold nanocages are especially effective in terms of transporting therapeutic drugs into a living organism.

Molecular cages are polyhedral structures, which are made up with smaller parts like protein molecules. In simple terms, the molecules are bonded or glued together using gold atoms.

Technically, the geometry of molecular polyhedrons is limited to three solid figures, according to researchers. However, researchers from Institute of Nuclear Physics built a tiny cage, which is similar in shape to a sphere out of eleven-walled proteins.

“Each of the walls of the new nanocages was formed by a protein ring from which eleven cysteine molecules stuck out at regular intervals,” according to researchers. “It was to the sulphur atom found in each cysteine molecule that the ‘glue’, i.e. the gold atom, was planned to be attached. In the appropriate conditions, it could bind with one more sulphur atom, in the cysteine of a next ring. In this way a permanent chemical bond would be formed between the two rings.”

Tomasz Wrobel from the Cracow Institute of Nuclear Physics of the Polish Academy of Sciences, added: “In the Spectroscopic Imaging Laboratory of IFJ PAS we used Raman spectroscopy and X-ray photoelectron spectroscopy to show that in the samples provided to us with the test nanocages, the gold really did form bonds with sulphur atoms in cysteines. In other words, in a difficult, direct measurement, we proved that gold ‘glue’ for bonding protein rings in cages really does exist.”

Scientists from the Malopolska Biotechnology Centre of the Jagiellonian University in Cracow, the Japanese RIKEN Institute in Wako and others contributed to the work.

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