This project will investigate a new class of materials, cryogenic electrorheological (ER) fluids. The research will determine the effective viscosity, shear stress, response time, column formation, and structure of these fluids. The program will examine the dynamic process of field-induced solidification an explore electro- and magneto-rheological properties of cryogenic ER fluids made of superconducting particles. The experimental and concurrent theoretical investigation is aimed at addressing fundamental science of ER fluids: the physical mechanisms and rheological and electrical properties of ER fluids. If successful, the results will form the basis for new technology employing cryogenic ER materials. %%% Electrorheological (ER) fluids are often referred to as intelligent fluids: Their rheological properties can be rapidly changed by an electric field. Hence, ER fluids have a wide variety of applications, such as shock absorbers, suspension systems, and clutches. This project will investigate cryogenic ER fluids which consist of fine dielectric particles, including superconducting particles, suspended in liquid nitrogen or liquid helium. The research will determine physical and a mechanical properties of the cryogenic ER fluids and dynamic structure formation. The comparison between cryogenic ER fluids and ER fluids at room temperature will provide significant new information about the fundamental physics of the ER effect. Moreover, the project may potentially establish the foundation for a low temperature technology based on ER phenomena and lead to practical applications in fluids engineering. ***
