4,039 research outputs found
Acoustic metafluids made from three acoustic fluids
Significant reduction in target strength and radiation signature can be
achieved by surrounding an object with multiple concentric layers comprised of
three acoustic fluids. The idea is to make a finely layered shell with the
thickness of each layer defined by a unique transformation rule. The shell has
the effect of steering incident acoustic energy around the structure, and
conversely, reducing the radiation strength. The overall effectiveness and the
precise form of the layering depends upon the densities and compressibilities
of the three fluids. Nearly optimal results are obtained if one fluid has
density equal to the background fluid, while the other two densities are much
greater and much less than the background values. Optimal choices for the
compressibilities are also found. Simulations in 2D and 3D illustrate
effectiveness of the three fluid shell. The limited range of acoustic
metafluids that are possible using only two fluid constituents is also
discussed.Comment: 12 pages, 11 figure
Home high above and home deep down below -- lending in Hungary
In Hungary in the pre-crisis period, the bank sector-initiated private credit boom significantly contributed to the accumulation of economic imbalances. Nevertheless, before the 2008 crisis no special regulatory measure was taken to mitigate the foreign exchange lending to unhedged borrowers, which was a main moving force of the credit boom. Depreciation of forint-denominated subsidized housing loans and the increased risk premium significantly deteriorated customers'positions and resulted in rocketing nonperforming loans. A recession, deteriorating portfolios, and lack of efficient workout. The introduction of strict regulation froze banking activity and the danger of recovery without lending emerged. This paper compares the pre- and post-crisis lending activity and analyzes the lack of regulation in the pre-crisis period and the inefficient regulation in the post-crisis period.Debt Markets,Banks&Banking Reform,Currencies and Exchange Rates,Bankruptcy and Resolution of Financial Distress,Emerging Markets
Nonself-adjoint semicrossed products by abelian semigroups
Let be the semigroup \mathcal{S}=\sum^{\oplus
k}_{i=1}\Sc{S}_i, where for each , is a countable
subsemigroup of the additive semigroup \B{R}_+ containing 0. We consider
representations of as contractions on
a Hilbert space with the Nica-covariance property: whenever
. We show that all such representations have a unique minimal
isometric Nica-covariant dilation.
This result is used to help analyse the nonself-adjoint semicrossed product
algebras formed from Nica-covariant representations of the action of
on an operator algebra by completely contractive
endomorphisms. We conclude by calculating the -envelope of the isometric
nonself-adjoint semicrossed product algebra (in the sense of Kakariadis and
Katsoulis).Comment: 14 page
On the renormalization of the bosonized multi-flavor Schwinger model
The phase structure of the bosonized multi-flavor Schwinger model is
investigated by means of the differential renormalization group (RG) method. In
the limit of small fermion mass the linearized RG flow is sufficient to
determine the low-energy behavior of the N-flavor model, if it has been rotated
by a suitable rotation in the internal space. For large fermion mass, the exact
RG flow has been solved numerically. The low-energy behavior of the
multi-flavor model is rather different depending on whether N=1 or N>1, where N
is the number of flavors. For N>1 the reflection symmetry always suffers
breakdown in both the weak and strong coupling regimes, in contrary to the N=1
case, where it remains unbroken in the strong coupling phase.Comment: 13 pages, 2 figures, final version, published in Physics Letters
Open Educational Resources (OER) for Control Systems Engineering: Development Case with LabVIEW, Simulink, and Camtasia
The aim of this paper is to report on the development
of control systems open educational resources. The
paper reports on two control systems education software: 1-
A LabVIEW based Control Systems Analysis Toolkit
(CSAT) which was developed to assist lecturers in teaching
control engineering and students to understand theoretical
concepts, and 2- A Process Control Virtual Laboratory
(PCVL), developed using LabVIEW. Both software have
been created as a stand-alone educational application together
with a detailed manual and learning activities. Existing
Simulink exercises have been enhanced and specific
video tutorials for the Simulink exercises have been developed.
Evaluations have been conducted indicating positive
impact on students
Electronic spectra of linear HCH and cumulene carbene HC
The transition of linear HCH
(A) has been observed in a neon matrix and gas phase. The assignment is based
on mass-selective experiments, extrapolation of previous results of the longer
HCH homologues, and density functional and multi-state CASPT2
theoretical methods. Another band system starting at 303 nm in neon is assigned
as the transition of the cumulene carbene
pentatetraenylidene HC (B).Comment: 7 pages, 4 figures, 5 table
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