Triplet lifetime in gaseous argon

MiniCLEAN is a single-phase liquid argon dark matter experiment. During the initial cooling phase, impurities within the cold gas ($<$140 K) were monitored by measuring the scintillation light triplet lifetime, and ultimately a triplet lifetime of 3.480 $\pm$ 0.001 (stat.) $\pm$ 0.064 (sys.) $\mu$s was obtained, indicating ultra-pure argon. This is the longest argon triplet time constant ever reported. The effect of quenching of separate components of the scintillation light is also investigated

Energy Harvesting by Oscillating Heat Pipes

Oscillating heat pipes (OHPs) have been actively investigated since their inception due to their ability to manage high heat/heat fluxes. The OHP is a passive, wickless, two-phase heat transfer device that relies on pressure driven fluid oscillations within a hermetically-sealed serpentine channel structure. The cyclic phase-change heat transfer drives additional sensible heat transfer, and this combination causes OHPs to have high effective thermal conductivities. Many strides have been made, through both experimentation and modeling, to refine the design and implementation of OHPs. However, the main objective in OHP research has been to better understand the thermodynamic and fluid mechanic phenomena so as to enhance OHPs\u27 thermal performance. The current work presents methods for using OHP in thermal-to-electric energy harvesting, which would allow for ‘dual-purpose’ OHP applications in which thermal management can be combined with work output. Energy harvesting occurred when a portion of the thermally-driven fluidic motion was used to generate a voltage either by electromagnetic induction or by a piezoelectric transducer imbedded in an OHP tube. For the induction approach, two methods were used to create the time-varying magnetic field required for induction. In the first, a ferrofluid was used as the OHP working fluid. Because the magnetic dipoles of the nanoparticles are randomly aligned naturally, two static, external ‘bias’ magnets were required to create a uniform magnetic field to align the particle dipoles for a non-zero magnetic flux change through a coaxial solenoid. The second method used a small rare-earth magnet confined inside a set length of an OHP channel that had a coaxial solenoid. As the OHP working fluid moved inside the harvesting channel, a portion of the fluid\u27s momentum was transferred to the magnet, causing it to oscillate. For the piezoelectric approach, a narrow piezoelectric transducer was placed in a bow-shaped configuration along the inside of an OHP channel. Passing fluid would deflect the piezo creating a potential difference across its leads, which protruded out of the channel walls. All three of these methods successfully produced a voltage while retaining the excellent thermal performance synonymous with OHPs

Christian Fundamentalists and Public Opinion Toward the Middle East: Israel's New Best Friends?

Although Christian fundamentalist elites have become increasingly vocal in their support for Israel in the ongoing conflict in the Middle East, it is not clear that this rhetoric has produced differing attitudes about U.S. foreign policy in public opinion. This article examines whether such differences exist, and whether they are rooted in aspects of fundamentalist eschatology. Copyright (c) 2004 by the Southwestern Social Science Association.