Massachusetts Institute of Technology

Exxon Research and Engineering Company

The Dexter Corporation

Illinois Superconductor Corporation, Inc.

Lewis Erwin

Neil F Newman

William M Davis

Ronald C Kowalski

Justin Whitney

Elizabeth C Leonard

John Arimond

John J Sparapany

Keith Crandell

Kevin J Prey

Jeffrey L Dohner

A cryogenic level sensor assembly. A sensor assembly includes a continuous length of high temperature ceramic superconductor material, an exterior housing for holding the length of ceramic superconductor material, a support material disposed between the ceramic superconductor material and the exterior housing, and a resilient retention material disposed opposite the ceramic superconductor material for holding the superconductor material while allowing expansion and contraction thereof during thermal cycling.

Cryogenic fluid level sensor

A process for etching polytetrafluoroethylene (PTFE) is disclosed herein which comprises defluorinating the surface layer of PTFE. The process includes exposing a sample of PTFE to the vapors of an alkali metal such that a layer of the fluoride of the alkali metal is formed on the surface of the PTFE sample and removing the fluoride of the alkali metal from the surface of the PTFE sample.

Process for etching polytetrafluoroethylene

A method of preparing a plurality of thermoset resin preforms by extruding a rod, cooling the rod to retain its dimensional uniformity and to reduce further curing of the resin, forming a plurality of grooves in the rod, and fracturing the rod at the grooves to yield the preforms.

Method of manufacture preforms

Liquids of different viscosity are mixed together more rapidly and with less energy consumption by elongating drops of the more-viscous liquid prior to mixing them into the less-viscous surrounding liquid. The more-viscous drops are elongated past a critical aspect ratio that is a function of the ratio of the viscosities of the two liquids and of the relative volume fractions they occupy. The rate at which the more-viscous drops mix into the surrounding liquid is dependent on the amount of shear strain required to stretch the drops to their critical aspect ratio, and thus, if the drops begin the mixing process already elongated, the rate of mixing is greater. In polymer blending operations, wherein a tumbled mixture of polymer pellets are melted and blended, the more-viscous pellets are elongated in the pelletizing operation. The mixing technique can be applied whenever the more-viscous drops are distributed discontinuously through a mixture, i.e., whenever they do not form a continously connected matrix. This occurs most often when the more-viscous liquid is in the minority, but may occur when it is in the majority.

Mixing liquids of different viscosity

Continuous halogenation of polymers is achieved by contacting polymer and halogenating agent in a continuous flow device in which the reactants are present as either co-continuous phases or wherein the halogenating agent is present as a continuous phase and the polymer is present as a discontinuous phase, the polymer is subjected to deformation during reaction and in which means are provided for disengaging reaction by-products and unreacted halogenating agent from the reaction mixture. In a preferred embodiment the polymer passes through three extruder-reactor zones under controlled conditions to achieve halogenation: feed, reaction (preferably vented), neutralization, and optionally a wash and exit zone. A continuous halogenating agent phase is achieved during reaction by avoiding complete filling of the reaction zone with polymer. Various halogenated polymers are produced, for example, halogenated linear low density polyethylene and halogenated butyl rubber.

Process for the manufacture of halogenated polymers

An apparatus and method for measuring particle agglomeration or dispersion in fluid mixtures, such as polymer melts, resides in a piezoelectric transducer, a spherical fused quartz lens, and a fluid housing. A repetitive, broadband, ultrasonic wave is produced by the transducer and is sent into the lens, which also serves to isolate the transducer from the mixture. The ultrasonic wave meets a spherical dimple at the end of the lens which focuses a portion of it into a diffraction limited spot or 'interrogation zone'. Since the intensity of the wave is large in the interrogation zone, small changes in the impedance of the fluid in this zone, caused by passing agglomerates, will cause large fluctuations in the intensity of the back scattered wave, which is monitored by the transducer between pulses and displayed by associated electronic elements.

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Winnetka, IL, United States of America

Lewis Erwin