Category: Research

Each year, the DOE’s Advanced Scientific Computing Research program, or ASCR, dedicates roughly 30% of the computing resources at its three supercomputing facilities to projects pursuing DOE mission research. The yearlong ASCR Leadership Computing Challenge (ALCC) awards, which begin July 1, aim to advance clean energy technologies, to better understand climate and environmental systems, and to respond to potential disasters.
ASCR recently awarded 19 new ALCC projects a total of 1.64 billion core-hours at the Argonne Leadership Computing Facility, expanding both the scope of scientific simulation research happening at ALCF and the community of researchers that will be capable of using a leadership-class system. Read more about the individual projects here.
Image: Christopher Knight, Argonne National Laboratory

A team of scientists has, for the first time, calculated several fundamental properties of the carbon-12 nucleus using one of the world’s fastest supercomputers, setting the stage for more reliable neutrino detector calibrations and better supernovae explosion simulations.
The work, published last summer in Physical Review Letters, involved researchers from Argonne, Los Alamos, and Jefferson national laboratories, Middle Tennessee State University, and Old Dominion University. The team, led by Argonne Senior Physicist Steven Pieper, was one of 16 that were granted early access to Mira last year, and used their core-hour allocation to prepare the Green’s function Monte Carlo (GFMC) code for the new machine’s scale and architecture in order to run the carbon-12 simulations.
In the past 15 years, researchers have developed the GFMC algorithm as a powerful and accurate method for computing properties of light nuclei. Understanding the many-body interactions within the nucleus is critical to a real understanding of the physics of nucleonic matter. Electron scattering experiments in the quasi-elastic regime, where the dominant process is knocking a single nucleon out of the nucleus, are underway at Jefferson Lab for a range of nuclei. Using Mira, the team has included new, complex interactions within the nucleus and predicted the results of a Jefferson Lab experiment, bringing theoretical prediction closer to experimental data in the high-momentum transfer tail. Read more about the work here.

The discovery last year at CERN of the Higgs boson — a particle that may well be responsible for all the mass in the universe — was momentous to physicists everywhere. The revelation of Higgs is critical to validating a nearly five-decade-old fundamental physics theory, known as the Standard Model, which accounts for all known subatomic particles and their interactions. Scientists, meanwhile, continue their search for answers to weighty unexplained physical phenomena such as the existence of dark matter and what happened to all the antimatter since the Big Bang.
Fermilab theoretical physicist Paul Mackenzie is leading a multiyear project at the ALCF to shed light on the mysterious particles and forces associated with “physics beyond the Standard Model.” According to Mackenzie, the Standard Model has many complex and peculiar features that have led to the nearly universal belief that there is new, as yet undiscovered physics which will explain these features.
Mackenzie heads a national effort to leverage HPC resources to advance quantum chromodynamics (QDC), the study of how quarks and gluons interact. Supercomputers like Mira enable scientists to study quarks and gluons in situations that are not possible in accelerator and cosmic ray experiments, and have the computational power needed to give quark-antiquark pairs their proper, very light masses for the first time — removing one of the largest remaining uncertainties involved in QCD calculations. Read more about Mackenzie’s research at the ALCF here.

In many ways, biofuel research is like modern day alchemy. The transmutation of biomass materials — which includes anything from kitchen and latrine waste to stalky, non-edible plants — into a sustainable and renewable energy source involves catalysts and chemical reactions. The process promises to help meet the world’s critical energy challenges.
Biofuel research can also be thought of as the ultimate multi-scale, multi-physics research problem. It represents several interesting biological supply-chain management problems. Not surprisingly, biofuel research spans several domains here at Argonne, and takes place in wet labs and joint institutes across the lab campus. There is also an exciting INCITE research project going on in the ALCF aimed at finding a more effective way to convert plant materials that contain cellulose, such as wood chips and switchgrass, into sugars, and then converted into biofuels.
A science team from the National Renewable Energy Laboratory is using Mira to conduct large-scale simulations of the complex cellulose-to-sugar conversion process. Researchers are able to obtain data, such as the level of an enzyme’s binding free energy, which is difficult to obtain through conventional experimental approaches, helping to accelerate the process of screening and testing new enzymes. With such information, researchers will be able to identify potential enzyme modifications and then feed their discoveries into experiments aimed at developing and validating improved catalysts. Read the full research highlight here.

The ASCR Leadership Computing Challenge projects that make up roughly 30% of the time awarded on ALCF supercomputers each year go to support “high-risk, high-payoff” simulations of interest to the DOE. Stanford’s Parviz Moin used his 60 million hour award to make a new and potentially industry-changing discovery about the source of supersonic jet noise. No ear protection needed.
Moin and his team ran large eddy simulations on Intrepid to determine the source of crackle in hot supersonic jet engines. Crackle is a major source of engine noise that causes hearing damage and impacts fuel efficiency. This particularly irritating phenomenon is associated with shock-like “N-shaped” acoustic waveforms consisting of sudden strong compressions followed by more gradual expansions. Because crackle occurs in the direction of peak jet noise, its elimination has the potential to help meet the U.S. Navy’s near-term jet noise reduction goal of 3 dB in the peak noise.
One way to make jets less noisy is to modify the shapes of the engine exhaust nozzles using pointed cutouts, called chevrons. Past ALCF allocations to Moin enabled a comprehensive study of the physical mechanisms by which chevrons affect the jet mixing and shock-associated noise. His current allocation was used to complete the simulations capturing crackle events and to develop new methods to identify and save such events for further study. Furthermore, with the source of the crackle noise now identified, new nozzle designs can be simulated.