278,432 research outputs found
Acoustic bubble removal method
A method is described for removing bubbles from a liquid bath such as a bath of molten glass to be used for optical elements. Larger bubbles are first removed by applying acoustic energy resonant to a bath dimension to drive the larger bubbles toward a pressure well where the bubbles can coalesce and then be more easily removed. Thereafter, submillimeter bubbles are removed by applying acoustic energy of frequencies resonant to the small bubbles to oscillate them and thereby stir liquid immediately about the bubbles to facilitate their breakup and absorption into the liquid
Rectification in Y-junctions of Luttinger liquid wires
We investigate rectification of a low-frequency ac bias in Y-junctions of
one-channel Luttinger liquid wires with repulsive electron interaction.
Rectification emerges due to three scatterers in the wires. We find that it is
possible to achieve a higher rectification current in a Y-junction than in a
single wire with an asymmetric scatterer at the same interaction strength and
voltage bias. The rectification effect is the strongest in the absence of the
time-reversal symmetry. In that case, the maximal rectification current can be
comparable with the total current even for low voltages, weak
scatterers and modest interaction strength. In a certain range of low voltages,
the rectification current can grow as the voltage decreases. This leads to a
bump in the - curve.Comment: 14 pages, 4 figures; The latest versio
Fluctuation-dissipation theorem for chiral systems in non-equilibrium steady states
We consider a three-terminal system with a chiral edge channel connecting the
source and drain terminals. Charge can tunnel between the chiral edge and a
third terminal. The third terminal is maintained at a different temperature and
voltage than the source and drain. We prove a general relation for the current
noises detected in the drain and third terminal. It has the same structure as
an equilibrium fluctuation-dissipation relation with the nonlinear response in
place of the linear conductance. The result applies to a general chiral system
and can be useful for detecting "upstream" modes on quantum Hall edges.Comment: detailed proo
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Thermal Modeling and Experimental Validation in the LENSâ„¢ Process
Several aspects of the thermal behavior of deposited stainless steel 410 (SS410) during the
Laser Engineered Net Shaping (LENSTM) process were investigated experimentally and
numerically. Thermal images in the molten pool and surrounding area were recorded using a
two-wavelength imaging pyrometer system, and analyzed using ThermaVizTM software to obtain
the temperature distribution. The molten pool size, temperature gradient, and cooling rate were
obtained from the recorded history of temperature profiles. The dynamic shape of the molten
pool, including the pool size in both travel direction and depth direction, was investigated and
the effect of different process parameters was illustrated. The thermal experiments were
performed in a LENSTM 850 machine with a 3kW IPG laser for different process parameters. A
three-dimensional finite element model was developed to calculate the temperature distribution
in the LENS process as a function of time and process parameters. The modeling results showed
good agreement with the experimental data.Mechanical Engineerin
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