Numerical modeling of 1D transient poroelastic waves in the low-frequency range

Propagation of transient mechanical waves in porous media is numerically investigated in 1D. The framework is the linear Biot model with frequency-independent coefficients. The coexistence of a propagating fast wave and a diffusive slow wave makes numerical modeling tricky. A method combining three numerical tools is proposed: a fourth-order ADER scheme with time-splitting to deal with the time-marching, a space-time mesh refinement to account for the small-scale evolution of the slow wave, and an interface method to enforce the jump conditions at interfaces. Comparisons with analytical solutions confirm the validity of this approach.     

Bounds to the size of halo nuclei

Inspired by the Bertlmann-Martin inequality relating the rms radius of the ground state wave function to the lowest dipole transition energy, we have proposed a dimensional relationship to be used in weakly bound two-body systems. In the present work, it is applied to halo nuclei. Lower and upper bounds to the size of halo nuclei are compared to values obtained from reaction cross sections. The case of the deuteron is also presented. Received: 18 September 1998     

FTIR Emission Spectra, Molecular Constants, and Potential Curve of Ground State GeO

Extensive new high-temperature, high-resolution FTIR emission spectroscopy measurements for the five common isotopomers of GeO are combined with previous diode laser and microwave measurements in combined isotopomer analyses. New Dunham expansion parameters and an accurate analytical potential energy function are determined for the ground X1Sigma+ state. Copyright 1999 Academic Press.     

Estimation of measurement uncertainty in food microbiology: The ISO approach

Given the current interest in measurement uncertainty (MU) in food microbiology, in particular for laboratory accreditation purposes, and the need to have harmonized reference documents specifically in that area at the international level, ISO is conducting works to meet this need. An ISO Technical Specification (ISO/TS 19036) is being prepared on MU estimation for quantitative determinations. A global approach has been chosen, based on the reproducibility standard deviation of the final result of the measurement process. Three possibilities are envisaged for the estimation of the reproducibility standard deviation, in a decreasing order of preference: The intra-laboratory standard deviation, the inter-laboratory standard deviation derived from method validation, and the inter-laboratory standard deviation derived from proficiency testing.The uncertainty of qualitative determinations is still under investigation, and will be covered by a separate ISO publication. Presented at AOAC Europe/Eurachem Symposium March 2005, Brussels, Belgium     

Bioconversion of mixed solids waste to ethanol

A mixed solids waste (MSW) feedstock, comprising construction lumber waste (35% oven-dry basis), alm ond treeprunings (20%), wheat straw (20%), office waste paper (12.5%), and newsprint (12.5%), was converted to ethanol via dilute-acid pretreatment followed by enzymatic hydrolysis and yeast fermentation. The MSW was pretreated with dilute sulfuricacid (0.4% w/w) at 210°C for 3 min in a 4-L stea mexplosion reactor, then washed with water to recover the solubilized hemicellulose. The digestibility of water-washed, pretreated MSW was 90% in batch enzymatic hydrolysis at 66 FPU/g cellulose. Using an enzyme-recycle bioreactor system, greater than 90% cellulose hydrolysis was achieved at a net enzyme loading of about 10 FPU/g cellulose. Enzyme recycling using mebrane filtration and a fed-batch fermentation technique is a promising option for significantly reducing the cost of enzyme in cellulose hydrolysis. The hexosesugars were readily fermentable using a Saccharomyces cerevisiae yeast strain that was adapted to the hydrolysate. Solid residue after enzyme digestion was subjected to various furnace experiments designed to assess the fouling and slagging characteristics. Results of these analyses suggest the residue to be of a low to moderate slagging and fouling type if burned by itself.     

Diffraction-limited polarized emission from a multimode ytterbium fiber amplifier after a nonlinear beam converter

The multimode and depolarized output beam of a highly multimode diode-pumped Yb-doped fiber amplifier is converted to a diffraction-limited, linearly polarized beam by a self-referencing two-wave-mixing process in an infrared-sensitive photorefractive crystal (Rh:BaTiO3). As much as 11.6 W of single-mode output is achieved with a 78% multimode-to-single-mode photorefractive conversion efficiency.     

Spectral analysis of 208Pb muonic atom

We have applied to the ²⁰⁸Pb muonic atom a series of recurrence relations relating the moments of the ground-state density and the energy differences between the 1s level and the states of the line. The large amount of precise experimental data and the electromagnetic character of the interaction allow a detailed test of the method for determining the ground-state density and reconstructing the local equivalent potential. Though the present work is limited to the study of the efficiency for a given trial density, it results in a semi-quantitative analysis with an accuracy better than 1%. Received: 18 December 2000 / Accepted: 18 April 2001     

Coherent beam combination of narrow-linewidth 1.5 μm fiber amplifiers in a long-pulse regime

We report what we believe to be the first experimental demonstration of coherent beam combining of two fiber amplifiers in a 100 ns pulse regime using a signal leak between the pulses. Pulses of ～100 W stimulated-Brillouin-scattering limited peak power are combined with 95% efficiency, a residual phase error of λ/27, and no significant beam quality degradation.     

Untersuchung von Fetten

Ohne Zusammenfassung     

Paramagnetic pyrrole-based semiconductor molecular material

The electrochemical oxidation of hexa-N-pyrrolylbenzene in organic media leads, via intramolecular coupling of the pyrrole residues, to the deposition of a molecular semiconductor film on an electrode surface. In situ electron spin resonance–electrochemical experiments reveal that the semiconductor is endowed with both properties of conducting polymers (i.e., reversible oxidation) and polyaromatic molecular materials (i.e., highly paramagnetic). The material, which is easy to process as soft homogeneous thin film, shows a tunable 0 to 1 spin concentration per molecule at room temperature by controlling the electrochemical potential. Contribution to the Fall Meeting of the European Materials Research Society, Symposium D: 9th International Symposium on the Electrochemical–Chemical Reactivity of Metastable Materials, Warsaw, 17th–21st September, 2007. An erratum to this article can be found at