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Preparation and Properties of In-Situ Devices Using the SALD and SALDVI Techniques
One of the many advantages of Selective Area Laser Deposition (SALD) and Selective
Area Laser Deposition Vapor Infiltration (SALDVI) is that they can be used to embed in-situ
micro-sensors within macro-components. A single-point SiC/C thermocouple sensor embedded
within a SiC macro-component and electrically insulated with silicon nitride layers has been
demonstrated. In many applications, multi-point sensors within a single component are needed,
e.g., in monitoring the temperature gradient and distribution at different positions. In this paper,
multi-point thermocouple devices are demonstrated. The macro-component is a SiC bulk shape
made by infiltrating vapor deposited silicon carbide into a silicon carbide powder bed using the
SALDVI technique. Multiple SiC/C thermocouples are embedded in-situ in the SiC bulk shape
using the SALD technique. The transient and steady state responses ofthe embedded
thermocouples are compared to reference thermocouples probing the surfaces of the bulk shape.Mechanical Engineerin
Artificial electric field in Fermi Liquids
Based on the Keldysh formalism, we derive an effective Boltzmann equation for
a quasi-particle associated with a particular Fermi surface in an interacting
Fermi liquid. This provides a many-body derivation of Berry curvatures in
electron dynamics with spin-orbit coupling, which has received much attention
in recent years in non-interacting models. As is well-known, the Berry
curvature in momentum space modifies naive band dynamics via an artificial
magnetic field in momentum space. Our Fermi liquid formulation completes the
reinvention of modified band dynamics by introducing in addition an "artificial
electric field", related to Berry curvature in frequency and momentum space. We
show explicitly how the artificial electric field affects the renormalization
factor and transverse conductivity of interacting U(1) Fermi liquids with
non-degenerate bands. Accordingly, we also propose a method of momentum
resolved Berry's curvature detection in terms of angle resolved photoemission
spectroscopy (ARPES)
Wave-like Solutions for Bianchi type-I cosmologies in 5D
We derive exact solutions to the vacuum Einstein field equations in 5D, under
the assumption that (i) the line element in 5D possesses self-similar symmetry,
in the classical understanding of Sedov, Taub and Zeldovich, and that (ii) the
metric tensor is diagonal and independent of the coordinates for ordinary 3D
space. These assumptions lead to three different types of self-similarity in
5D: homothetic, conformal and "wave-like". In this work we present the most
general wave-like solutions to the 5D field equations. Using the standard
technique based on Campbell's theorem, they generate a large number of
anisotropic cosmological models of Bianchi type-I, which can be applied to our
universe after the big-bang, when anisotropies could have played an important
role. We present a complete review of all possible cases of self-similar
anisotropic cosmologies in 5D. Our analysis extends a number of previous
studies on wave-like solutions in 5D with spatial spherical symmetry
Economic Analysis of a Traveling Gun for Feedyard Dust Suppression
Dust created in feedyards can adversely affect cattle performance. Dust suppression can be accomplished by moistening pen surfaces with traveling gun(s) sprinklers, solid-set sprinklers, and water trucks. This study specifically addresses the fixed and operational costs associated with a traveling gun sprinkler system for various sized feedyards.traveling gun, dust suppression, fixed costs, operational costs, Livestock Production/Industries,
An exact self-similar solution for an expanding ball of radiation
We give an exact solution of the Einstein equations which in 4D can be
interpreted as a spherically symmetric dissipative distribution of matter, with
heat flux, whose effective density and pressure are nonstatic, nonuniform, and
satisfy the equation of state of radiation. The matter satisfies the usual
energy and thermodynamic conditions. The energy density and temperature are
related by the Stefan-Boltzmann law. The solution admits a homothetic Killing
vector in , which induces the existence of self-similar symmetry in 4D,
where the line element as well as the dimensionless matter quantities are
invariant under a simple "scaling" group.Comment: New version expanded and improved. To appear in Int. J. Mod. Phys.
Propagating EUV disturbances in the solar corona : two-wavelength observations
Quasi-periodic EUV disturbances simultaneously observed in 171 Ć
and 195 Ć
TRACE bandpasses propagating outwardly in a fan-like magnetic structure of a coronal active region are analysed. Time series of disturbances observed in the different bandpasses have a relatively high correlation coefficient (up to about 0.7). The correlation has a tendency to decrease with distance along the structure: this is consistent with an interpretation of the disturbances in terms of parallel-propagating slow magnetoacoustic waves. The wavelet analysis does not show a significant difference between waves observed in different bandpasses. Periodic patterns of two distinct periods: 2-3 min and 5-8 min are detected in both bandpasses, existing simultaneously and at the same distance along the loop, suggesting the nonlinear generation of the second harmonics
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