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Full-Text Articles in Physics

Droplet Evaporation And Deformations In An Amplitude Modulated Ultrasonic Field, Nihad E. Daidzic, Rene Stadler, Adrian Melling Apr 1996

Droplet Evaporation And Deformations In An Amplitude Modulated Ultrasonic Field, Nihad E. Daidzic, Rene Stadler, Adrian Melling

Aviation Department Publications

The aim of the report presented is the measurements of droplet oscillations.


Synthesis And Characterization Of Boron-Containing Polymeric Materials For Neutron Shielding Applications, Michael B. Glasgow Jan 1996

Synthesis And Characterization Of Boron-Containing Polymeric Materials For Neutron Shielding Applications, Michael B. Glasgow

Dissertations, Theses, and Masters Projects

The development of boron-containing polymeric materials for neutron shielding applications was undertaken. Three types of materials were characterized for physical and thermal properties: boron powder-filled epoxy composites, carborane polyamides having boron chemically bonded into the polymer, and boron-loaded polyimide thin films. Addition of amorphous submicron boron powder did not affect significantly the thermal performance of the epoxy. The 17% boron loading produced a 26% increase in compressive failure strength and a 68% increase in the compressive modulus. 0.125 inch thick specimens containing 17% boron absorbed 92% of incident neutrons from a 5-Curie Pu/Be source compared with {dollar}<{dollar}1% for the neat epoxy. Dispersion of the boron in the epoxy was improved with the addition of larger size crystalline boron powders. Carborane polyamides containing up to 35% boron were thermally stable up to 400{dollar}\sp\circ{dollar}C in air. The polymers had hydrogen/boron ratios from 2.0 to 3.8 and were soluble in several organic solvents. Polymer solutions were processed into clear, colored thin films. Boron-filled polyamic acid solutions of a PMDA-ODA polyimide containing up to 10% boron were processed into thin films. Neutron absorption of the opaque films measured in a 5-Curie Pu/Be neutron source was linear with boron concentration and film thickness. The fraction of neutrons absorbed varied linearly with boron concentration and film thickness. The applicability of boron-containing materials to the aerospace, nuclear power and accelerator industries was investigated.