205 research outputs found
Development of Stress Relief Treatments for High Strength Aluminum Alloys Annual Report No. 2, 13 Aug. 1964 - 13 Aug. 1965
Residual stress, strength, and toughness response of high strength aluminum alloys subjected to time-temperature treatment
Plasma Oscillations and Expansion of an Ultracold Neutral Plasma
We report the observation of plasma oscillations in an ultracold neutral
plasma. With this collective mode we probe the electron density distribution
and study the expansion of the plasma as a function of time. For classical
plasma conditions, i.e. weak Coulomb coupling, the expansion is dominated by
the pressure of the electron gas and is described by a hydrodynamic model.
Discrepancies between the model and observations at low temperature and high
density may be due to strong coupling of the electrons.Comment: 4 pages, 4 figures. Accepted Phys. Rev. Let
SCIMPI: A New Borehole Observatory
The Simple Cabled Instrument for Measuring Parameters in-situ (SCIMPI) is a new borehole observatory instrument designed to study dynamic processes below the seafloor. SCIMPI performs time series measurements of temperature, pressure and electrical resistivity at a series of depths, tailored for site-specific scientific objectives. SCIMPI’s modular design enables tailoring of the type, depth distribution, and frequency of measurements based on the study goals and sediment characteristics. The first prototype is designed for 300m below the seafloor in soft sediment and 1500mb.s.l. However, SCIMPI could be tailored for deeper goals. The instrument can be configured for autonomous or cabled observatory deployments and has successfully undergone a number of tests, including pressure, communications, battery life, and interfacing with other drill-ship equipment. Here we discuss the design of the instrument, its capabilities, and the testing process it has passed through during four years of development. SCIMPI was successfully deployed on the Cascadia margin within the NEPTUNE Canada observatory network during IODP Expedition 341S in May 2013
A single hollow beam optical trap for cold atoms
We present an optical trap for atoms that we have developed for precision
spectroscopy measurements. Cold atoms are captured in a dark region of space
inside a blue-detuned hollow laser beam formed by an axicon. We analyze the
light potential in a ray optics picture and experimentally demonstrate trapping
of laser-cooled metastable xenon atoms.Comment: 12 pages, 8 figure
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