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in subjects: "Aspect Ratio"  
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Monitoring Permeable Reactive Barriers using Electrical Resistance Tomography

Description: An electrical resistivity tomography (ERT) method is being evaluated as a measurement tool to determine the integrity of permeable reactive barriers (PRBs) during and after construction of the barrier and as a monitoring tool to determine the long-term operational health of the barrier. The method is novel because it inserts the electrodes directly into the barrier itself. Numerical modeling calculations indicate that the ERT method can detect flaws (voids) in the barrier as small as 0.11 m{sup… more
Date: December 8, 2003
Creator: Ramirez, A.; Bratton, W.; Maresca, J.; Daily, W. & Dickerson, W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Progress towards Steady State at Low Aspect Ratio on the National Spherical Torus Experiment (NSTX)

Description: Modifications to the plasma control capabilities and poloidal field coils of the National Spherical Torus Experiment (NSTX) have enabled a significant enhancement in shaping capability which has led to the transient achievement of a record shape factor (S ≡ q95 (Iρ⁄ αΒτ)) of ∼41 (MA m−1 Τ−1) simultaneous with a record plasma elongation of κ ≡ β ⁄ α ∼ 3. This result was obtained using isoflux control and real-time equilibrium reconstruction. Achieving high shape factor together with tolerable di… more
Date: November 8, 2007
Creator: D.A. Gates, J. Menard, R. Maingi, S. Kaye, S.A. Sabbagh, S. Diem, J.R.Wilson, M.G. Bell, R.E. Bell, J. Ferron, E.D. Fredrickson, C.E. Kessel, B.P. LeBlanc, F. Levinton, J. Manickam, D. Mueller, R. Raman, T. Stevenson, D. Stutman, G. Taylor, K. Tritz, H. Yu, and the NSTX Research Team
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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High-Aspect-Ratio Nanophotonic Components Fabricated by Cl(2) RIBE

Description: We describe highly anisotropic reactive ion beam etching of nanophotonic structures in AlGaAs based on the ion beam divergence angle and chamber pressure. The divergence angle is shown to influence the shape of the upper portion of the etch while the chamber pressure controls the shape of the lower portion. This predictable region of parameter space resulted in highly anisotropic nanostructures. Deeply etched distributed Bragg reflectors are etched to an aspect ratio of 8:1 with 100 nm trench w… more
Date: July 8, 1999
Creator: Zubrzycki, W. J.; Vawter, G. A. & Wendt, J. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Physics Results from the National Spherical Torus Experiment

Description: The National Spherical Torus Experiment (NSTX) produces plasmas with aspect ratio A {triple_bond} R/a = 0.85m/0.68m {approx} 1.25, at plasma currents up to 1.5 MA with vacuum toroidal magnetic field up to 0.6 T on axis. The plasmas are heated by up to 6 MW of High-Harmonic Fast Waves (HHFW) at a frequency 30 MHz and by 7 MW of deuterium Neutral Beam Injection (NBI) at an energy up to 100 keV. Since January 2004, NSTX has been operating, routinely at toroidal fields up to 0.45 T, with a new cent… more
Date: July 8, 2004
Creator: Team, M.G. Bell for the NSTX Research
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Three-dimensional poisson solver for a charged beam with large aspect ratio in a conducting pipe

Description: In this paper, we present a three-dimensional Poisson equation solver for the electrostatic potential of a charged beam with large longitudinal to transverse aspect ratio in a straight and a bent conducting pipe with open-end boundary conditions. In this solver, we have used a Hermite-Gaussian series to represent the longitudinal spatial dependence of the charge density and the electric potential. Using the Hermite-Gaussian approximation, the original three-dimensional Poisson equation has been… more
Date: January 8, 2004
Creator: Qiang, Ji & Gluckstern, Robert L.
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Partner: UNT Libraries Government Documents Department
open access

Mechanical Testing of EPON SU-8 With SIEM

Description: High aspect ratio structures are often present in MEMS devices and EPON SU-8 is often used to produce such structures because of its low cost. It is essential to know the mechanical properties of SU-8 for producing reliable MEMS products. However, the mechanical properties of SU-8 may depend on the manufacturing process and the size of the structure, which is in the micron domain. Hence, one needs to test specimens that are similar in size to MEMS structures to determine if the mechanical prope… more
Date: June 8, 2000
Creator: Chang, S.; Warren, J. & Chiang, F. P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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