2,032 research outputs found
Optical Limiting in Single-walled Carbon Nanotube Suspensions
Optical limiting behaviour of suspensions of single-walled carbon nanotubes
in water, ethanol and ethylene glycol is reported. Experiments with 532 nm, 15
nsec duration laser pulses show that optical limiting occurs mainly due to
nonlinear scattering. The observed host liquid dependence of optical limiting
in different suspensions suggests that the scattering originates from
microbubbles formed due to absorption-induced heating.Comment: 10 pages, 5 eps figures, to appear in Chem. Phys. Let
A REAL TIME MONITORING MODEL OF THE CALCIUM CARBONATE FOULING INDUCTION PERIOD BASED ON THE CONDUCTANCE TITRATION
A new method has been developed to monitor the calcium carbonate fouling induction period (CCFIP) in real time. Based on the conductance titration, this paper investigated the forming process of CCFIP by a staticdynamic combined simulation experiment unit. With the help of titration analysis (that is titrimetry), an accurate definition of CCFIP and the corresponding real time monitoring model were built up. The investigation results show that the proposed model applies not only to measure the CCFIP in real time, but also applies to an investigation of the influence of various factors on the CCFIP
Finite Size Scaling for Low Energy Excitations in Integer Heisenberg Spin Chains
In this paper we study the finite size scaling for low energy excitations of
and Heisenberg chains, using the density matrix renormalization
group technique. A crossover from behavior (with as the chain length)
for medium chain length to scaling for long chain length is found for
excitations in the continuum band as the length of the open chain increases.
Topological spin excitations are shown to give rise to the two lowest
energy states for both open and periodic chains. In periodic chains these
two excitations are ``confined'' next to each other, while for open chains they
are two free edge 1/2 spins. The finite size scaling of the two lowest energy
excitations of open chains is determined by coupling the two free edge
spins. The gap and correlation length for open Heisenberg chains
are shown to be 0.082 (in units of the exchange ) and 47, respectively.Comment: 4 pages (two column), PS file, to be appear as a PRB Brief Repor
Optimal behavior of viscoelastic flow at resonant frequencies
The global entropy generation rate in the zero-mean oscillatory flow of a
Maxwell fluid in a pipe is analyzed with the aim at determining its behavior at
resonant flow conditions. This quantity is calculated explicitly using the
analytic expression for the velocity field and assuming isothermal conditions.
The global entropy generation rate shows well-defined peaks at the resonant
frequencies where the flow displays maximum velocities. It was found that
resonant frequencies can be considered optimal in the sense that they maximize
the power transmitted to the pulsating flow at the expense of maximum
dissipation.Comment: Paper accepted to be published in Phys. Rev.
Determination of micro-scale plastic strain caused by orthogonal cutting
An electron beam lithography technique has been used to produce microgrids in order to measure local plastic strains, induced during an orthogonal cutting process, at the microscopic scale in the shear zone and under the machined surface. Microgrids with a 10 μm pitch and a line width less than 1 μm have been printed on the polished surface of an aluminium alloy AA 5182 to test the applicability of the technique in metal cutting operations. Orthogonal cutting tests were carried out at 40 mm/s. Results show that the distortion of the grids could successfully be used to compute plastic strains due to orthogonal cutting with higher accuracy compared to other techniques reported in the literature. Strain maps of the machined specimens have been produced and show high-strain gradients very close to the machined surface with local values reaching 2.2. High-resolution strain measurements carried out in the primary deformation zone also provide new insight into the material deformation during the chip formation process
Fluorescence Efficiency and Visible Re-emission Spectrum of Tetraphenyl Butadiene Films at Extreme Ultraviolet Wavelengths
A large number of current and future experiments in neutrino and dark matter
detection use the scintillation light from noble elements as a mechanism for
measuring energy deposition. The scintillation light from these elements is
produced in the extreme ultraviolet (EUV) range, from 60 - 200 nm. Currently,
the most practical technique for observing light at these wavelengths is to
surround the scintillation volume with a thin film of Tetraphenyl Butadiene
(TPB) to act as a fluor. The TPB film absorbs EUV photons and reemits visible
photons, detectable with a variety of commercial photosensors. Here we present
a measurement of the re-emission spectrum of TPB films when illuminated with
128, 160, 175, and 250 nm light. We also measure the fluorescence efficiency as
a function of incident wavelength from 120 to 250 nm.Comment: 15 pages, 9 figures, Submitted to Nuclear Instruments and Methods in
Physics Research Section A: Accelerators, Spectrometers, Detectors and
Associated Equipmen
The Haldane gap for the S=2 antiferromagnetic Heisenberg chain revisited
Using the density matrix renormalization group (DMRG) technique, we carry out
a large scale numerical calculation for the S=2 antiferromagnetic Heisenberg
chain. Performing systematic scaling analysis for both the chain length and
the number of optimal states kept in the iterations , the Haldane gap
is estimated accurately as . Our systematic
analysis for the S=2 chains not only ends the controversies arising from
various DMRG calculations and Monte Carlo simulations, but also sheds light on
how to obtain reliable results from the DMRG calculations for other complicated
systems.Comment: 4 pages and 1 figur
TRIC-A Prevents Store-Overload Induced Calcium Release Through Interaction with the Cardiac Ryanodine Receptor
Earthquake damage estimation systems: Literature review
Earthquake is an unpredictable natural phenomenon that create a vast amount of damage, affecting communities and their environment. To reduce the effects of such hazards, frameworks like building resilience have emerged. These frameworks target on increasing recovery after such disaster, by introducing new designs, technologies, and components to the building. To calculate the value of such improvements, use of loss estimation systems are essential. This paper compares and contrasts two most widely adopted loss assessment tools available, namely PACT and SLAT. Comparison of these tools mainly focuses on the consequence functions of the two methods. Recommendations are suggested to improve and complement these tools in future use
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