44,079 research outputs found
Contamination Control Handbook for Ground Fluid Systems Final Technical Publication
Handbook for contamination control of aerospace ground fluid systems and portable equipmen
Fluoride solid lubricants for extreme temperatures and corrosive environments
Fluoride solid lubricants for extreme temperature and corrosive environment
Thermal decomposition of a honeycomb-network sheet - A Molecular Dynamics simulation study
The thermal degradation of a graphene-like two-dimensional triangular
membrane with bonds undergoing temperature-induced scission is studied by means
of Molecular Dynamics simulation using Langevin thermostat. We demonstrate that
the probability distribution of breaking bonds is highly peaked at the rim of
the membrane sheet at lower temperature whereas at higher temperature bonds
break at random anywhere in the hexagonal flake. The mean breakage time
is found to decrease with the total number of network nodes by a power law
and reveals an Arrhenian dependence on temperature .
Scission times are themselves exponentially distributed. The fragmentation
kinetics of the average number of clusters can be described by first-order
chemical reactions between network nodes of different coordination. The
distribution of fragments sizes evolves with time elapsed from a
-function through a bimodal one into a single-peaked again at late
times. Our simulation results are complemented by a set of -order
kinetic differential equations for which can be solved exactly and
compared to data derived from the computer experiment, providing deeper insight
into the thermolysis mechanism.Comment: 21pages, 9 figures, LaTeX, revised versio
Remote Detection of Saline Intrusion in a Coastal Aquifer Using Borehole Measurements of Self-Potential
Funded by NERC CASE studentship . Grant Number: NE/I018417/1Peer reviewedPublisher PD
Driving light pulses with light in two-level media
A two-level medium, described by the Maxwell-Bloch (MB) system, is engraved
by establishing a standing cavity wave with a linearly polarized
electromagnetic field that drives the medium on both ends. A light pulse,
polarized along the other direction, then scatters the medium and couples to
the cavity standing wave by means of the population inversion density
variations. We demonstrate that control of the applied amplitudes of the
grating field allows to stop the light pulse and to make it move backward
(eventually to drive it freely). A simplified limit model of the MB system with
variable boundary driving is obtained as a discrete nonlinear Schroedinger
equation with tunable external potential. It reproduces qualitatively the
dynamics of the driven light pulse
Bank liquidity creation and risk taking during distress
Liquidity creation is one of banks' raisons d'être. But what happens to liquidity creation and risk taking when a bank is identified as distressed by regulatory bodies and subjected to regulatory interventions and/or receives capital injections? What are the long-run effects of such interventions? To address these questions, we exploit a unique dataset of German universal banks for the period 1999 - 2008. Our main findings are as follows. First, regulatory interventions and capital injections are followed by lower levels of liquidity creation. The probability of a decline in liquidity creation increases to up to around 50 percent when such actions are taken. Second, bank risk taking decreases in the aftermath of regulatory interventions and capital injections. Third, while banks' liquidity creation market shares decline over the five years following such disciplinary measures, they also reduce their risk exposure over this period to become safer banks. --Liquidity creation,bank distress,regulatory interventions,capital injections
Thermally activated breakdown in a simple polymer model
We consider the thermally activated fragmentation of a homopolymer chain. In
our simple model the dynamics of the intact chain is a Rouse one until a bond
breaks and bond breakdown is considered as a first passage problem over a
barrier to an absorbing boundary. Using the framework of the Wilemski-Fixman
approximation we calculate activation times of individual bonds for free and
grafted chains. We show that these times crucially depend on the length of the
chain and the location of the bond yielding a minimum at the free chain ends.
Theoretical findings are qualitatively confirmed by Brownian dynamics
simulations
Diffusion of a Janus nanoparticle in an explicit solvent: A molecular dynamics simulation study
Molecular dynamics simulations are carried out to study the translational and
rotational diffusion of a single Janus particle immersed in a dense
Lennard-Jones fluid. We consider a spherical particle with two hemispheres of
different wettability. The analysis of the particle dynamics is based on the
time-dependent orientation tensor, particle displacement, as well as the
translational and angular velocity autocorrelation functions. It was found that
both translational and rotational diffusion coefficients increase with
decreasing surface energy at the nonwetting hemisphere, provided that the
wettability of the other hemisphere remains unchanged. We also observed that in
contrast to homogeneous particles, the nonwetting hemisphere of the Janus
particle tends to rotate in the direction of the displacement vector during the
rotational relaxation time.Comment: Web reference added for
animations:http://www.wright.edu/~nikolai.priezjev/janus/janus.htm
Debt maturity, risk, and asymmetric information
We test the implications of Flannery’s (1986) and Diamond’s (1991) models concerning the effects of risk and asymmetric information in determining debt maturity, and we examine the overall importance of informational asymmetries in debt maturity choices. We employ data from more than 6,000 commercial loans from 53 large U.S. banks. Our results for low-risk firms are consistent with the predictions of both theoretical models, but our findings for high-risk firms conflict with the predictions of Diamond’s model and with much of the empirical literature. Our findings also suggest a strong quantitative role for asymmetric information in explaining debt maturity.
BEC-BCS crossover in a cold and magnetized two color NJL model
The BEC-BCS crossover for a NJL model with diquark interactions is studied in
the presence of an external magnetic field. Particular attention is paid to
different regularization schemes used in the literature. A thorough comparison
of results is performed for the case of a cold and magnetized two-color NJL
model. According to our results, the critical chemical potential for the BEC
transition exhibits a clear inverse magnetic catalysis effect for magnetic
fields in the range . As for the BEC-BCS
crossover, the corresponding critical chemical potential is very weakly
sensitive to magnetic fields up to , showing a much smaller
inverse magnetic catalysis as compared to the BEC transition, and displays a
strong magnetic catalysis from this point on.Comment: 15 pages, 8 figures; v2 PRD versio
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