Tyler O'Neal, Staff Editor CHEMISTRY

SwRI, UTSA win $1.5 million grant to study hypersonic separation events

Southwest Research Institute will advance hypersonics research in collaboration with The University of Texas at San Antonio (UTSA) under a three-year, $1.5 million grant through the University Consortium of Applied Hypersonics. As a subcontractor to UTSA, SwRI will design experiments to push the envelope on what is capable with hypersonic system designs and provide methods to better model complex system behavior during separation events.

Hypersonic speeds are faster than five times the speed of sound or greater than Mach 5. When something is flying that fast, the air around a flying object will chemically decompose. Some points behind the shockwave created by the vehicle are hotter than the surface of the Sun. This strange chemical environment causes whatever is traveling through it to heat up, and even melt and chemically react with the air.

SwRI engineers, led by Nicholas Mueschke, program manager of SwRI’s Computational Mechanics Section, are studying hypersonic separation events when two or more things intentionally come apart.

Separation events are commonplace in many aerospace applications. For example, rocket boosters are ejected during space launches, including some that now return to the launch pad after separation. Military aircraft require safe separation of payloads carried underwing or within storage bays.  Some rocket nose cones are designed to protect launch packages, such as satellites, which split open and separate from the vehicle in flight.

“Flying at hypersonic speeds within the atmosphere makes the aerodynamics and loads experienced by separating structures more difficult to predict and harder to safely design around because the time scales of these events are squeezed into milliseconds,” Mueschke said.

As next-generation hypersonic technology progresses, the ability to support separating components must also advance. A booster that separates from a vehicle, for example, allows for extended range and novel flight corridors. The challenge is designing components that can separate easily, avoid damaging or upsetting the primary vehicle, but also withstand the extreme aerodynamics and thermal environment associated with traveling at hypersonic speeds. Southwest Research Institute’s two-stage light-gas gun simulates hypersonic flight conditions and allows researchers to image objects in hypersonic flight. It will be instrumental in the Institute’s efforts to design experiments that advance knowledge of hypersonic separation events.

SwRI is designing novel experiments to evaluate hypersonic system designs while also providing methods to better model complex system behavior during separation events. To accomplish this, the team is designing tests that can be conducted in the Institute’s two-stage light-gas gun, which simulates hypersonic flight conditions and allows researchers to image objects in hypersonic flight.

“The goal is to generate aerodynamic and kinematic data that will anchor high-fidelity simulation models,” Mueschke said. “We will also leverage some of our advanced simulation capabilities to both design these experiments and evaluate how simulation models can improve future vehicle designs. Ultimately, this work is part of the broader effort to leverage hypersonic technology to deliver operational capability and options to combatant commanders that otherwise don’t exist today.”

Mueschke and his colleagues began work under the new contract in October.

“It’s encouraging to see academia, government, and industry collaborating on multiyear efforts to advance hypersonics research,” Mueschke said. “I hope this effort will open new doors to operational capabilities we haven’t seen before.”

Bristol scientists demo new tool to tackle climate change at COP26

Tyler O'Neal, Staff Editor CHEMISTRY

Leading atmospheric scientists are measuring emissions of the most dangerous greenhouse gases at COP26 and sharing them live online to highlight how rigorous measurement and detailed data reporting are essential in the fight against climate change. Measurements of carbon dioxide and methane are being made at COP26 from the Glasgow Science Centre Tower, as pictured, in central Glasgow. National Physical Laboratory

The initiative, by the University of Bristol, UK, and an international team of scientists deploy sophisticated instrumentation to measure the amount of carbon dioxide (CO2) and methane (CH4) – the main culprits in driving global warming – present in the air in Glasgow, where this year’s United Nations Climate Change Conference is being hosted.

The same technology is used in a wider Bristol-led project in partnership with the Met Office to gather this data from across the UK, called the Deriving Emissions linked to Climate Change (DECC) network. This globally unique system is used to check the accuracy of the UK government’s greenhouse gas emissions report to the United Nations.  

Experts from the team are involved in events and presentations at the 13-day summit to demonstrate how timely measurements present a vital but little-used tool to accurately monitor and effectively tackle climate change.

Prof. Matt Rigby, Professor of Atmospheric Chemistry at the university’s Cabot Institute for the Environment, said: “The UK is world-leading in its evaluation of emissions of greenhouse gases, including the two which pose the biggest threat to our planet. The aim of this work is to demonstrate the huge potential of this technology, and urge other countries to follow, especially the industrial powerhouses of China, the US, and India.”

A feed of the Glasgow data in real-time is available on an online dashboard and the statistics are being carefully analyzed by the team to identify possible trends and issues.

Professor Rigby said: “Advanced measurement and tightly-scrutinized evaluation of emissions is imperative to detect any irregularities which may warrant further investigation and to enable countries, including the UK, to meet crucial targets to curb emissions and limit global warming. This approach can help ensure accurate, consistent, and reliable emissions reporting to build and evidence progress.”

Government reporting of Greenhouse Gases (GHGs) is based on “bottom-up” or inventory accountancy methods, which calculate the national total contribution to climate change by estimating emissions from individual gas leaks, cars, cows, etc., and adding up the total number of each contributor. Although comprehensive, they can be subject to substantial inaccuracies. These reports do not generally consider arguably key information: measurements that can indicate the actual amount of greenhouse gas in the atmosphere.

By contrast, the team measures real-time levels of GHGs in the atmosphere across the UK and uses supercomputer models based on meteorological data to produce “top-down” emissions estimates. The UK was the first country to use this measurement-based approach to evaluate its GHG emission reports to the UN and is currently one of only three countries, including Switzerland and Australia, to do so.

Professor Alistair Manning, an atmospheric modeling expert at the Met Office, added: “As the UK government routinely cross-check with their figures against our top-down emissions estimates, the credibility of the UK reporting is greatly enhanced. By raising awareness of these methods at COP26 we hope that other countries will be encouraged to follow the UK’s lead, in turn improving the accuracy of the global emissions reporting system, which needs to become more consistent and robust.”

Hospital for Special Surgery sponsors the DREAM Challenge to develop better ML for assessment of damage in arthritis

Tyler O'Neal, Staff Editor CHEMISTRY

Crowdsourcing has become an increasingly popular way to develop machine learning algorithms to address many clinical problems in a variety of illnesses. Today at the American College of Rheumatology (ACR) annual meeting, a multicenter team led by an investigator from Hospital for Special Surgery (HSS) presented the results from the RA2-DREAM Challenge, a crowdsourced effort focused on developing better methods to quantify joint damage in people with rheumatoid arthritis (RA).

Damage in the joints of people with RA is currently measured by visual inspection and detailed scoring on radiographic images of small joints in the hands, wrists, and feet. This includes both joint space narrowing (which indicates cartilage loss) and bone erosions (which indicates damage from an invasion of the inflamed joint lining). The scoring system requires specially trained experts and is time-consuming and expensive. Finding an automated way to measure joint damage is important for both clinical research and for the care of patients, according to the study’s senior author, S. Louis Bridges, Jr., MD, Ph.D., physician-in-chief, and chair of the Department of Medicine at HSS.

“If a machine-learning approach could provide a quick, accurate quantitative score estimating the degree of joint damage in hands and feet, it would greatly help clinical research,” he said. “For example, researchers could analyze data from electronic health records and from genetic and other research assays to find biomarkers associated with progressive damage. Having to score all the images by visual inspection ourselves would be tedious, and outsourcing it is cost-prohibitive.”

“This approach could also aid rheumatologists by quickly assessing whether there is progression of damage over time, which would prompt a change in treatment to prevent further damage,” he added. “This is really important in geographic areas where expert musculoskeletal radiologists are not available.”

For the challenge, Dr. Bridges and his collaborators partnered with Sage Bionetworks, a nonprofit organization that helps investigators create DREAM (Dialogue on Reverse Engineering Assessment and Methods) Challenges. These competitions are focused on the development of innovative artificial intelligence-based tools in the life sciences. The investigators sent out a call for submissions, with grant money providing prizes for the winning teams. Competitors were from a variety of fields, including computer scientists, computational biologists, and physician-scientists; none were radiologists with expertise or training in reading radiographic images.

For the first part of the challenge, one set of images was provided to the teams, along with known scores that had been visually generated. These were used to train the algorithms. Additional sets of images were then provided so the competitors could test and refine the tools they had developed. The third set of images was given without scores in the final round, and competitors estimated the amount of joint space narrowing and erosions. Submissions were judged according to which most closely replicated the gold-standard visually generated scores. 26 teams submitted algorithms and 16 final submissions. In total, competitors were given 674 sets of images from 562 different RA patients, all of whom had participated in prior National Institutes of Health-funded research studies led by Dr. Bridges. In the end, four teams were named top performers.

For the DREAM Challenge organizers, it was important that any scoring system developed through the project be freely available rather than proprietary, so that it could be used by investigators and clinicians at no cost. “Part of the appeal of this collaboration was that everything is in the public domain,” Dr. Bridges said.

Dr. Bridges explained that additional research and development of computational methods are needed before the tools can be broadly used, but the current research demonstrates that this type of approach is feasible. “We still need to refine the algorithms, but we’re much closer to our goal than we were before the Challenge,” he concluded.