Efforts to make superconducting materials more durable have earned Tufts University Assistant Professor of Mechanical Engineering Luisa Chiesa a five-year grant for $750,000 from the U.S. Department of Energy's new Early Career Research Program.
Chiesa's goal is to pursue research and education in superconducting materials and magnet systems for large fusion energy reactors in order to understand their electro-mechanical behavior under low and high temperature conditions.
In fusion, the magnet creates a powerful magnetic field that is essential for containing and forming the very high-temperature plasma. To do this, the magnet and cables used to produce the magnetic field must be cold. "To contain very high temperature plasma that's millions of degrees, you can use powerful magnets made of materials that can only operate if they are really cold," says Chiesa.
Magnets and cables are made of expensive metal compounds. While the process is successful in generating a large magnetic field to confine the plasma from which energy is extracted, it also causes the magnets and cables to degrade. Chiesa will study the mechanical behaviors of superconducting materials to determine how they might be designed to work more efficiently without degradation.
An NSF early career grant was awarded to Valencia Joyner, assistant professor of electrical and computer engineering, for her research into time-resolved near infrared spectroscopy (NIRS). The $541,000 grant is for five years.
Optical methods such as NIRS are emerging as promising non-invasive imaging tools for fundamental study of biological processes and structures, and to examine human tissue to identify disease. However, visibility of superficial and deep structures using optical methods remains fairly poor because of sensor equipment limitations.
Joyner's goal is to develop high-performance optical sensors to capture light that passes through tissue with superior spatial mapping, faster optical response time and simultaneous measurement of multiple light signals to increase the visibility-millimeter structures.
Sameer Sonkusale, assistant professor of electrical and computer engineering, received a five-year $400,000 NSF early career award for his work in developing promising new techniques to assemble and grow nano-sized wires on silicon chips. Nanowires can be used in sensing devices to detect diseases in any bodily fluid, including urine and saliva.
In Sonkusale's two approaches, CMOS chips generate an electrical field that is precisely controlled to position nanomaterials to specific locations on the chip. In his technique for nanoassembly, a solution of suspended nanomaterials is incorporated directly onto a silicon chip. A well-controlled AC electric field is applied on metal electrodes of the chip. By manipulating the electrical field, the researchers can control the location, quantity and quality of the nanowire formation on the chip.
In a second technique, which is known as nanofabrication, Sonkusale has proposed growing nanowires using the template of nanoporous membranes such as anodic aluminum oxide directly on the chip. The nanopores can be dissolved in a solvent after nanowire growth leaving behind free-standing nanowires.
Sonkusale says that his second technique allows nanowires of different types (metal, metal oxides, semiconductors) to be produced faster and at lower costs than conventional photolithography, which uses extreme ultraviolet light to pattern nanowires mostly of a single type on chips.