140 research outputs found
Sovereign illiquidity and recessions
Motivated by the striking increase in sovereign spreads and the subsequent recession in Europe during 2011, I examine the importance of sovereign debt liquidity in a New Keynesian environment with wage rigidities and nancial frictions a la Kiyotaki and Moore (2012). My main ndings imply that, independently of credit risk, a decrease in the liquidity of government bonds has signi cant detrimental e ects on output, employment, investment, and equity prices. Therefore, this framework suggests that ECB policies taken in 2012 aimed at introducing liquidity seem to be the desired measures, at least temporally until conventional monetary policy became e ective again
Compound strip method for the analysis of continuous elastic plates
Item deaccessioned after digitization.A finite strip method (FSM) is developed for the analysis of Iinear elastic flat plate systems which are continuous over deflecting supports. The approach presented incorporates the effect of the support elements in a direct stiffness methodology. The stiffness contribution of the support elements have been derived and are given In the form of strip matrices which are directly added to the plate strip stiffness matrix at the element level. This summation of plate and support stiffness contributions constitutes a substructure which is termed a compound strip. The validity of the compound strip method is demonstrated in several illustratlve problems which include single and muitlpanel plates continuous over flexible and rigid beams and columns. The FSM and finite element method (FEM) compare favorably for displacement and moment. The rate of convergence of the compound strip method was studied and results are given for a continuous multipanel system. The FSM is shown to be computationally more efficient than the FEM when maximum values for moment or deflection are required. The FEM exhibits favorable convergence characteristics in locations where the magnitudes of displacement and moment are relatively small
Angular correlation of scattered annihilation photons, to test the possibility of hidden variables in quantum theory
Angular correlations of the annihilation photons, Compton scattered by plastic scintillators and detected by means of NaI (T1) crystals, have been measured in order to test the possibility of deviations of the experimental results from the predictions of the quantum theory
Repair of Full-scale Timber Bridge Chord members by Shear Spiking
The addition of vertically-oriented shear spikes (fiberglass reinforced polymer rods) was shown to increase the effective stiffness of the stringers of a full-scale timber bridge chord specimen. Results found from the flexural load testing of a full-scale timber bridge chord laboratory specimen are presented. Reinforcement was provided with 19 mm diameter shear spikes bonded to the wood by an epoxy resin. The bridge chord specimen was intentionally damaged to simulate degradation. Shear spikes were then installed from the top of the member into pre‑drilled holes to provide horizontal shear resistance and to improve the flexural effective stiffness. Results from the testing showed that with the insertion of five sets of shear spikes the average flexural effective stiffness recovered in the four stringers of the chord was 91.6%
Composite Wood–Concrete Structural Floor System with Horizontal Connectors
The concept of horizontal shear connection utilization on wood–concrete beams intends to be an alternative connection detail for composite wood–concrete decks. The volume of sawn-wood is over three times more expensive than concrete, in Brazil. In order to be competitive in the Brazilian market we need a composite deck with the least amount of wood and a simple and inexpensive connection detail. This research project uses medium to high density tropical hardwoods managed from the Brazilian Amazon region and construction steel rods. The beams studied are composed of a bottom layer of staggered wood boards and a top layer of concrete. The wood members are laterally nailed together to form a wide beam, and horizontal rebar connectors are installed before the concrete layer is applied on top. Two sets of wood–concrete layered beams with horizontal rebar connectors (6 and 8) were tested in third-point loading flexural bending. The initial results reveal medium composite efficiency for the beams tested. An improvement on the previously conceived connection detail (set with six connectors) for the composite wood–concrete structural floor system was achieved by the set with eight connectors. The new layout of the horizontal rebar connectors added higher composite efficiency for the beams tested. Further analysis with advanced rigorous numerical Finite Element Modeling is suggested to optimize the connection parameters. Composite wood–concrete decks can attend a large demand for pedestrian bridges, as well as residential and commercial slabs in the Brazilian Amazon. © 2014, The Author(s)
Action at a distance as a full-value solution of Maxwell equations: basis and application of separated potential's method
The inadequacy of Li\'{e}nard-Wiechert potentials is demonstrated as one of
the examples related to the inconsistency of the conventional classical
electrodynamics. The insufficiency of the Faraday-Maxwell concept to describe
the whole electromagnetic phenomena and the incompleteness of a set of
solutions of Maxwell equations are discussed and mathematically proved. Reasons
of the introduction of the so-called ``electrodynamics dualism concept"
(simultaneous coexistence of instantaneous Newton long-range and
Faraday-Maxwell short-range interactions) have been displayed. It is strictly
shown that the new concept presents itself as the direct consequence of the
complete set of Maxwell equations and makes it possible to consider classical
electrodynamics as a self-consistent and complete theory, devoid of inward
contradictions. In the framework of the new approach, all main concepts of
classical electrodynamics are reconsidered. In particular, a limited class of
motion is revealed when accelerated charges do not radiate electromagnetic
field.Comment: ReVTeX file, 24pp. Small corrections which do not have influence
results of the paper. Journal reference is adde
Kinematics and hydrodynamics of spinning particles
In the first part (Sections 1 and 2) of this paper --starting from the Pauli
current, in the ordinary tensorial language-- we obtain the decomposition of
the non-relativistic field velocity into two orthogonal parts: (i) the
"classical part, that is, the 3-velocity w = p/m OF the center-of-mass (CM),
and (ii) the so-called "quantum" part, that is, the 3-velocity V of the motion
IN the CM frame (namely, the internal "spin motion" or zitterbewegung). By
inserting such a complete, composite expression of the velocity into the
kinetic energy term of the non-relativistic classical (i.e., newtonian)
lagrangian, we straightforwardly get the appearance of the so-called "quantum
potential" associated, as it is known, with the Madelung fluid. This result
carries further evidence that the quantum behaviour of micro-systems can be
adirect consequence of the fundamental existence of spin. In the second part
(Sections 3 and 4), we fix our attention on the total 3-velocity v = w + V, it
being now necessary to pass to relativistic (classical) physics; and we show
that the proper time entering the definition of the four-velocity v^mu for
spinning particles has to be the proper time tau of the CM frame. Inserting the
correct Lorentz factor into the definition of v^mu leads to completely new
kinematical properties for v_mu v^mu. The important constraint p_mu v^mu = m,
identically true for scalar particles, but just assumed a priori in all
previous spinning particle theories, is herein derived in a self-consistent
way.Comment: LaTeX file; needs kapproc.st
Dipolar origin of the gas-liquid coexistence of the hard-core 1:1 electrolyte model
We present a systematic study of the effect of the ion pairing on the
gas-liquid phase transition of hard-core 1:1 electrolyte models. We study a
class of dipolar dimer models that depend on a parameter R_c, the maximum
separation between the ions that compose the dimer. This parameter can vary
from sigma_{+/-} that corresponds to the tightly tethered dipolar dimer model,
to R_c --> infinity, that corresponds to the Stillinger-Lovett description of
the free ion system. The coexistence curve and critical point parameters are
obtained as a function of R_c by grand canonical Monte Carlo techniques. Our
results show that this dependence is smooth but non-monotonic and converges
asymptotically towards the free ion case for relatively small values of R_c.
This fact allows us to describe the gas-liquid transition in the free ion model
as a transition between two dimerized fluid phases. The role of the unpaired
ions can be considered as a perturbation of this picture.Comment: 16 pages, 13 figures, submitted to Physical Review
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