Mechanical Engineering Commons^™

Order-Disorder Transition Of Aragonite Nanoparticles In Nacre, Zaiwang Huang, Xiaodong Li

Faculty Publications

Understanding nacre’s bottom-up biomineralization mechanism, particularly, how individual aragonite platelets are formed, has long remained elusive due to its crystallographic peculiarity and structural complexity. Here we report that crystallographic order-disorder transition can be triggered within individual aragonite platelets in pristine nacre by means of heat treatment and/or inelastic deformation, offering a unique opportunity to discriminate mysterious aragonite nanoparticles in transmission electron microscopy. Our findings unambiguously uncover why aragonite nanoparticles in pristine nacre have long been inaccessible under TEM observation, which is attributed to the monocrystal-polycrystal duality of the aragonite platelet. The underlying physical mechanism for why an individual aragonite platelet …

Development Of Oxidizer Flow Control For Use In Hybrid Rocket Motors Of The Scientific Sounding Rocket Scale, Luke Saindon

Honors College

To successfully build a rocket engine with variable thrust you must devise a reliable and robust oxidizer flow control system. The goal of this thesis is to contribute to the goal of building a variable thrust (throttled) hybrid rocket engine, which could eventually be used to power scientific sounding rockets. A variable thrust hybrid engine would increase reusability, flexibility, and capability of almost any small rocket.

Specifically, this thesis work regards the development of the closed loop oxidizer flow control system. To do this, a small test rig was built in the lab that consists of all the components in …