Professor Robert Hyers of the Mechanical and Industrial Engineering (MIE) Department has received a $600,000, four-year grant from NASA for a project investigating “Thermophysical Properties and Transport Phenomena Models and Experiments in Reduced Gravity.”
“In plain language, the objective of the project is to advance our understanding of the manufacturing of a family of nonlinear optical crystals,” explains Hyers. “These crystals can be used to construct a wide range of devices, including three-dimensional holographic storage. However, manufacturing problems limit the performance and availability of these devices. This project will examine some theories about the origin of the manufacturing problems, taking us one step closer to widespread availability of these devices.”
Professor Jong Lee from the MIE department is co-investigator on this project, and there are also international collaborators from Japan, Germany, and Korea. The project proposed by Hyers will take advantage of the Electrostatic Levitation Furnace and the reduced gravity on the International Space Station to perform experiments that could never be conducted effectively on Earth.
Hyers’ project was developed to answer a NASA request for projects in the Materials Science MaterialsLab of the International Space Station dealing with “Thermophysical Property Measurements, Materials Processes Affecting Microstructure and Composition, Biomaterials, and Biofilms Liquid Crystals.”
As Hyers explains, photorefractive materials have the property that their refractive index is changed by exposure to light. Such devices allow the control of light by light, enabling dozens of new kinds of photonic devices ranging from holographic storage to adaptive optics. Photorefractivity is characteristic of materials that are both photoconductive (light excites mobile charge carriers) and electro-optic (the index of refraction changes under an electric field). Two of the most promising host materials for these devices are Bismuth Sillenite and the corresponding Bismuth Germanate.
These materials have been the topic of thousands of technical articles over the past 35 years. However, commercialization of devices based on these materials is currently limited by the homogeneity of the host crystals, according to Hyers.
The ultimate objective of the proposed program is the commercial development of new photonic devices.
The program proposed by Hyers will consist of four major elements:
- continued development of novel non-contact methods for measuring thermophysical properties, including using electrostatic levitation in reduced gravity;
- application of these methods to materials of interest to industry and the international scientific community;
- application of the measured properties to produce accurate models of fluid flow and heat and mass transfer in the levitated samples;
- and application of the measured properties and models to test theories about the effect of processing on microstructure and material characteristics of a family of nonlinear optical crystals.
Hyers notes that the proposed elements vary in scope from the development of methods which are broadly applicable to measurement of thermophysical properties such as density and viscosity, to measurement of the properties of samples proposed by the Hyers team and other investigators in MaterialsLab, to models for specific experiments. Through the insight into the transport phenomena inside the samples, the experiment-specific models enable experiments that would otherwise be impossible.
“Similar models are currently in use for model enabled experiments on the International Space Station,” says Hyers. “The results of the model-enabled experiments will advance the scientific understanding of the effect of processing on the properties of non-linear optical crystals, moving them closer to commercial production and sale here on Earth.” (August 2016)