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Solid-Phase Extraction of Polar Compounds From Water

A solid-phase extraction (SPE) process has been developed for removing alcohols, carboxylic acids, aldehydes, ketones, amines, and other polar organic compounds from water. This process can be either a subprocess of a water-reclamation process or a means of extracting organic compounds from water samples for gas-chromatographic analysis.

Posted in: Physical Sciences, Briefs

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Efficient Computational Model of Hysteresis

A useful approximate model applies to quasistatic displacements. A recently developed mathematical model of the output (displacement) versus the input (applied voltage) of a piezoelectric transducer accounts for hysteresis. For the sake of computational speed, the model is kept simple by neglecting the dynamic behavior of the transducer. Hence, the model applies to static and quasistatic displacements only. A piezoelectric transducer of the type to which the model applies is used as an actuator in a computer-based control sys- tem to effect fine position adjustments. Because the response time of the rest of such a system is usually much greater than that of a piezoelectric transducer, the model remains an acceptably close approximation for the purpose of control computations, even though the dynamics are neglected.

Posted in: Physical Sciences, Briefs, TSP

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Verifying the Safety of a Radioactive Waste Container With Simulation Software

Simulating drop tests helped ensure structural integrity of a contaminated glovebox. As part of decommissioning the U.S. Department of Energy (DOE) Hanford Site — an inactive nuclear facility in southeastern Washington — a contaminated apparatus called a glovebox (a steel isolation chamber with built-in gloves that allow personnel to remotely manipulate radioactive materials) needed to be removed and transported to the on-site Environmental Restoration Disposal Facility (ERDF) landfill, and then buried safely without exposing people or the environment to harmful radiation.

Posted in: Physical Sciences, Briefs

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Gauges for Highly Precise Metrology of a Compound Mirror

High precision is achieved through careful attention to details of complex designs. Three optical gauges have been developed for guiding the assembly and measuring precisely the reflecting surfaces of a compound mirror that comprises a corner-cube retroreflector glued in a hole on a flat mirror. In the specific application for which the gauges were developed, the compound mirror is part of a siderostat in a stellar interferometer. The flat-mirror portion of the compound mirror is the siderostat mirror; the retroreflector portion of the compound mirror is to be used, during operation of the interferometer, to monitor the location of the siderostat mirror surface relative to other optical surfaces of the interferometer. Nominally, the optical corner of the retroreflector should lie precisely on the siderostat mirror surface, but this precision cannot be achieved in fabrication: in practice, there remains some distance between the optical corner and the siderostat mirror surface. For proper operation of the interferometer, it is required to make this distance as small as possible and to know this distance within 1 nm. The three gauges make it possible to satisfy these requirements.

Posted in: Physical Sciences, Briefs, TSP

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Improved Electrolytic Hydrogen Peroxide Generator

Energy efficiency exceeds that of a prior electrolytic H2O2 generator. An improved apparatus for the electrolytic generation of hydrogen peroxide dissolved in water has been developed. The apparatus is a prototype of H2O2 generators for the safe and effective sterilization of water, sterilization of equipment in contact with water, and other applications in which there is need for hydrogen peroxide at low concentration as an oxidant. Potential applications for electrolytic H2O2 generators include purification of water for drinking and for use in industrial processes, sanitation for hospitals and biotechnological industries, inhibition and removal of biofouling in heat exchangers, cooling towers, filtration units, and the treatment of wastewater by use of advanced oxidation processes that are promoted by H2O2. The apparatus is an electrochemical cell in which the electrodes are located on opposite sides of a commercially available polymeric membrane, which separates the electrolytes of the two electrolytic half-reactions.

Posted in: Physical Sciences, Briefs

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Modified Penning-Malmberg Trap for Storing Antiprotons

One set of electrodes is used for both transmission and reception.

Posted in: Physical Sciences, Briefs

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Tumbleweed Rovers

Lightweight balls containing scientific instruments are propelled across terrain by wind.

Posted in: Physical Sciences, Briefs, TSP

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