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Darnell M. Cage
University of Missouri-Columbia
Department of Mechanical and Aerospace Engineering
Advisors: William G. Zhao and Gary L. Solbbrekken
Department of Veterinary Pathobiology
Advisors: John K. Critser and Xu Han
Abstract
This research is focused on improving the design of vials for cryopreservation. Traditional vials used for cryogenic storage of biological specimens such as blood and cells are generally constructed out of plastic or glass and can be sealed to offer a pathogenic barrier. The vials also are transparent and of low cost. Unfortunately, they have poor heat transfer characteristics. Of particular note is the relatively low thermal diffusivity of biological samples and the cylindrical geometry employed by current vials creates a spatially non-uniform cooling environment. This leads to spatially non-uniform cooling rates of the samples.
The numerical heat transfer simulations show conventional cylindrical vials have significant non-uniformity of temperature and cooling rates when the vial is assumed to be plunged into liquid nitrogen. Numeric simulations of the vials confirmed the spatially non-uniform temperature and cooling rates. Simulations on new geometric configurations of vials with larger surface-area-to-volume ratios showed spatially more uniform temperature distributions and cooling rates. This paper will review the results of those models as well as experimental measurements taken on an off-the-shelf cylindrical vial and a geometrically modified vial. The experiments were conducted by placing a thermocouple with a 25 micro-meter bead at various locations in the vials. The vials were then plunged into liquid nitrogen while a high-speed data acquisition system measured the transient thermocouple temperature response. The measurement results are compared with the model responses.
Darnell Cage hails from Saint Louis, MO and is currently a freshman undertaking Mechanical Engineering with an Aerospace emphasis at the University of Missouri - Columbia (Mizzou). He is working with Dr. Gary Solbrekken and the Mechanical Engineering department of the College of Engineering on his research entitled "Numerical Simulations and Experimental Evaluations of Heat Transfer Performance of Improved Cryogenic Vials for Cryopreservation". At Mizzou, Darnell is involved in the Mizzou Black Male's Initiative, National Society of Black Engineer, American Society of Mechanical Engineers, and Diversity in Engineering. He is also a George C. Brooks scholar, Diversity in Engineering scholar, Chamber's scholar in engineering, Gates Millennium scholar, William L. Clay scholar, and William Pablo Feraldo scholar. This summer, he plans to intern with Pratt and Whitney in Middleton Connecticut. After graduating with his Bachelor's degree in Mechanical Engineering, he plans to attend graduate school to further his education with hopes of opening his own engineering firm.
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