Computer program ETC improves computation of elastic transfer matrices of Legendre polynomials P/0/ and P/1/

Computer program ETC improves computation of elastic transfer matrices of Legendre polynomials P/0/ and P/1/. Rather than carrying out a double integration numerically, one of the integrations is accomplished analytically and the numerical integration need only be carried out over one variable

ETC - A Fortran 4 program for computing the multigroup P/0/ and P/1/ elastic transfer coefficients

Fortran 4 program for calculating multigroup elastic transfer coefficient

Expanding the toolbox for nanoparticle trapping and spectroscopy with holographic optical tweezers

We have developed a workstation based on holographic tweezers to optically trap, move and characterize metal nanoparticles. Our advanced darkfield imaging system allows us to simultaneously image and take spectra of single trapped metal nanoparticles. We take advantage of the beamshaping abilities of the spatial light modulator and correct for aberrations of the trapping optics. We monitor the improvement of the optical trap with video-based nanoparticle tracking. Furthermore we theoretically assess the capabilities and limitations of video-based tracking for nanoparticle position detection, in particular with respect to acquisition frequencies below the corner frequency

Preparation of microscopic cross sections of U235 for reactor calculations

Preparation of microscopic cross section of uranium 235 for high temperature reactor calculation

Single-level resonance parameters fit nuclear cross-sections

Least squares analyses of experimental differential cross-section data for the U-235 nucleus have yielded single level Breit-Wigner resonance parameters that fit, simultaneously, three nuclear cross sections of capture, fission, and total

Turbulence and turbulent mixing in natural fluids

Turbulence and turbulent mixing in natural fluids begins with big bang turbulence powered by spinning combustible combinations of Planck particles and Planck antiparticles. Particle prograde accretions on a spinning pair releases 42% of the particle rest mass energy to produce more fuel for turbulent combustion. Negative viscous stresses and negative turbulence stresses work against gravity, extracting mass-energy and space-time from the vacuum. Turbulence mixes cooling temperatures until strong-force viscous stresses freeze out turbulent mixing patterns as the first fossil turbulence. Cosmic microwave background temperature anisotropies show big bang turbulence fossils along with fossils of weak plasma turbulence triggered as plasma photon-viscous forces permit gravitational fragmentation on supercluster to galaxy mass scales. Turbulent morphologies and viscous-turbulent lengths appear as linear gas-proto-galaxy-clusters in the Hubble ultra-deep-field at z~7. Proto-galaxies fragment into Jeans-mass-clumps of primordial-gas-planets at decoupling: the dark matter of galaxies. Shortly after the plasma to gas transition, planet-mergers produce stars that explode on overfeeding to fertilize and distribute the first life.Comment: 23 pages 12 figures, Turbulent Mixing and Beyond 2009 International Center for Theoretical Physics conference, Trieste, Italy. Revision according to Referee comments. Accepted for Physica Scripta Topical Issue to be published in 201

Assembly and force measurement with SPM-like probes in holographic optical tweezers

We report a high fidelity tomographic reconstruction of the quantum state of photon pairs generated by parametric down-conversion with orbital angular momentum (OAM) entanglement. Our tomography method allows us to estimate an upper and lower bound for the entanglement between the down-converted photons. We investigate the two-dimensional state subspace defined by the OAM states ±ℓ and superpositions thereof, with ℓ=1, 2, ..., 30. We find that the reconstructed density matrix, even for OAMs up to around ℓ=20, is close to that of a maximally entangled Bell state with a fidelity in the range between F=0.979 and F=0.814. This demonstrates that, although the single count-rate diminishes with increasing ℓ, entanglement persists in a large dimensional state space

Pressure containment tests in support of the nuclear Brayton cycle heat exchanger and duct assembly /HXDA/, phase 2

Plate-fin heat exchangers for nuclear reactor Brayton cycl

Increasing trap stiffness with position clamping in holographic optical tweezers

We present a holographic optical tweezers system capable of position clamping multiple particles. Moving an optical trap in response to the trapped object's motion is a powerful technique for optical control and force measurement. We have now realised this experimentally using a Boulder Nonlinear Systems Spatial Light Modulator (SLM) with a refresh rate of 203Hz. We obtain a reduction of 44% in the variance of the bead's position, corresponding to an increase in effective trap stiffness of 77%. This reduction relies on the generation of holograms at high speed. We present software capable of calculating holograms in under 1ms using a graphics processor unit. © 2009 Optical Society of America