Rongchao Jin and his group have found a way to control the lifetime of the quantum states of gold nanoclusters by three orders of magnitude, which could lead to improvements in solar cell and photocatalysis technologies. Their study is published in the April 18 issue of Science.
In the news
John Keith, assistant professor of chemical and petroleum engineering at the University of Pittsburgh Swanson School of Engineering, has received two awards to fund a 10-month collaboration with a researcher at the University of Luxembourg.
Dr. Keith received the equivalent of $89,000 from the Luxembourg National Research Fund as well as a $26,746 NSF Travel Award supplement to support a 10-month visit to the University of Luxembourg, where he will work with Prof. Alexandre Tkatchenko, a world expert in developing atomistic machine learning methods that use artificial intelligence to make computer simulations faster and more accurate.
Together, the researchers will study complex reaction mechanisms, such as carbon dioxide conversion into fuels and chemicals, and environmentally green chemical design of molecular chelating agents.
The researchers also plan to develop a modern textbook on quantum chemistry and contemporary methods to study chemical bonding that would educate the next generation of computational researchers.
Written by Maggie Pavlick.
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Jill Millstone is the 2019 recipient of the Award for Career Excellence in the Chemical Sciences from the Pittsburgh Women Chemists Committee. This award recognizes the achievements of female chemists and chemical engineers in the greater Pittsburgh area who have a record of accomplishment in their field.
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The nuclear industry in the U.S. is at a crossroads, as several plants are scheduled for permanent shutdown, including three in Pennsylvania, the second-largest nuclear energy-producing state. However, Heng Ban, director of the Swanson School’s Stephen R. Tritch Nuclear Engineering Program, sees opportunity ahead for students, alumni and faculty researchers.
“Nuclear energy is one of the cleanest power resources and is a vital component not only of our nation’s energy portfolio, but also the U.S. naval nuclear fleet and several countries around the world. Research is ongoing into additive manufacturing of nuclear components, smaller reactor systems as well as sensors and controls for reactor safety and machine learning for facility maintenance,” Dr. Ban says.
Dr. Ban adds that since many of those engineers are nearing retirement, there is a great need for a new generation of nuclear employees.
“From Bettis, Westinghouse, Bechtel Marine and so many other in the supply chain, employers are telling us not only that they need engineers, but are helping us structure the curriculum so that we educate the best engineer for the field.”
“As long as nuclear energy remains a reliable, clean, efficient and safe energy resource, we will have a greater need for the engineers who can be competitive in the global nuclear energy marketplace, as well as who can develop the next ground-breaking technologies,” Dr. Ban says. “And the Swanson School is at the nexus of this industry that is a critical part of our national safety, from power generation to defense, and a major contributor to reducing carbon emissions worldwide.”
Feng Xiong and Jonathan Malen, received a $500,000 award from the National Science Foundation to develop a thermoelectric semiconductor using tungsten disulfide to convert waste heat into energy. Using a novel doping approach, they will enhance the tungsten disulfide’s electrical conductivity while lowering its thermal conductivity—it will be able to efficiently conduct electricity without conducting heat. Tungsten disulfide is thin and flexible, making it a promising new option with diverse potential uses.
The project length is three years, with a possible extension into a fourth. The award is split between Dr. Xiong’s lab ($270,000) and Dr. Malen’s lab ($230,000). The team will work closely with local communities to encourage students from all backgrounds to explore engineering careers and foster interest in nanotechnology. Outreach efforts will include lab demonstrations, summer internships and career workshops.
The ability to combine continuously tunable narrow-band terahertz (THz) generation that can access both the far-infrared and mid-infrared regimes with nanometer-scale spatial resolution is highly promising for identifying underlying light-matter interactions and realizing selective control of rotational or vibrational resonances in nanoparticles or molecules. Here, we report selective difference frequency generation with over 100 THz bandwidth via femtosecond optical pulse shaping. The THz emission is generated at nanoscale junctions at the interface of LaAlO3/SrTiO3 (LAO/STO) that is defined by conductive atomic force microscope lithography, with the potential to perform THz spectroscopy on individual nanoparticles or molecules. Numerical simulation of the time-domain signal facilitates the identification of components that contribute to the THz generation. This ultra-wide-bandwidth tunable nanoscale coherent THz source transforms the LAO/STO interface into a promising platform for integrated lab-on-chip optoelectronic devices with various functionalities.
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Peyman Givi, developer of the Filtered Density Function (FDF) used in very high fidelity numerical simulation of chemically reactive flow fields, will co-chair a mini symposium on the subject at the 17th International Conference on Numerical Combustion (NC19) in Aachen, Germany from May 6-8, 2019. The mini symposium “Filtered Density Function Methods for Turbulent Reactive Flows” will include 60 participants and 28 presented papers. According to Dr. Givi, participants will learn the latest developments and innovations in enhancing the computational and predictive capabilities of the FDF methodology.
Sangyeop Lee is co-author of a recent article, “Survey of ab initio phonon thermal transport” in Materials Today Physics (vol. 7, 2018, pp. 106-120, DOI 10.1016/j.mtphys.2018.11.008). This article provides a comprehensive survey of first-principles Peierls-Boltzmann thermal transport as developed in the literature over the last decade, with particular focus on more recent advances. This review will demonstrate the wide variety of calculations accessible to first-principles transport methods (including dimensionality, pressure, and defects), highlight unusual properties and predictions that have been made, and discuss some challenges and behaviors that lie beyond.
Dr. Lee, who joined Pitt in 2015, studies nanoscale thermal transport in solid materials, and his research is currently focused on hydrodynamic phonon transport in graphitic materials and thermal transport in fully or partially disordered phase. His group utilizes Boltzmann transport theory, Green's function method, and molecular dynamics simulation, all of which use interatomic force constants calculated from density functional theory. He earned his BS and MS in mechanical and aerospace engineering from the Korea Advanced Institute of Science and Technology, and PhD in mechanical engineering from MIT.
Written by Paul Kovach.
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To advance the understanding of micro- and nano-surfaces and to engineer more stable nanoparticles, the National Science Foundation has awarded the University of Pittsburgh’s Tevis Jacobs a $500,000 CAREER Award, which supports early-career faculty who have the potential to serve as academic role models in research and education and to lead advances in the mission of their department or organization. Dr. Jacobs, assistant professor of mechanical engineering and materials science at Pitt’s Swanson School of Engineering, will utilize electron microscopy to directly study and measure adhesion properties of nanoparticles and their supporting substrates.
Dr. Jacobs noted that current processes to counter nanoparticle coarsening utilize stabilizing materials, but matching the most effective stabilizer to a nanoparticle is a time-consuming and costly trial-and-error process. The CAREER award will enable Dr. Jacobs and his lab group to develop new methods to measure the attachment and stability of nanoparticles on surfaces under various conditions, allowing researchers to enhance both surfaces and nanoparticles in tandem to work more effectively together.
Written by Paul Kovach.
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Hrvoje Petek, R.K. Mellon Professor in the Department of Physics and Astronomy, has received the Ahmed Zewali Award in Ultrafast Science & Technology from the American Chemical Society. Petek will be honored during an awards ceremony April 2 during the 257th ACS national meeting in Orlando.