A parallel Krylov-Schur implementation for large Hermitian and non-Hermitian eigenproblems

This work presents a new implementation of a Krylov-Schur eigensolver in SLEPc (Scalable Library for Eigenvalue Problem Computations), a software library for the solution of large, sparse eigenvalue problems on parallel computers. Some parallel performance results are given, showing better scalability compared to ARPACK. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effect of pH on growth and fatty acid composition ofLactobacillus büchneri andLactobacillus fermentum

Growth and fatty acid composition of two lactobacilli,Lactobacillus büchneri andLactobacillus fermentum, were studied at different pHs of the media in a small-scale fermenter with particular interest in lactobacillic acid production of the cultures. Generally, the total fatty acid content of the bacterial cells increased with increasing culture age. The production of lactobacillic acid was affected in the two lactobacilli by both culture age and pH of the media, but in a very different manner. In L.büchneri cultures, the relative proportion of lactobacillic acid was highest when the pH was lowest (pH 4.5), whereas inL. fermentum cultures, the proportion of lactobacillic acid was highest at pH 7.0. The pH of the medium affected not only the relative proportion of lactobacillic acid, but also biomass production and total fatty acid accumulation of the cultures. Thus, by controlling the pH of the cultures, the volumetric yield of lactobacillic acid could be improved considerably compared to cultures without pH control.     

Reversible water uptake by a stable imine-based porous organic cage

A crystalline porous organic cage molecule, CC3, is shown to adsorb up to 20.1 wt% water reversibly. This was confirmed by both gravimetric sorption and by crystallographic analysis. Crystals of CC3 are stable in boiling water for at least 4 h. The surprising chemical and supramolecular stability of these imine-based molecular crystals suggests scope for practical applications in humid environments.     

Speech production in noise with and without hearing protection

People working in noisy environments often complain of difficulty communicating when they wear hearing protection. It was hypothesized that part of the workers' communication difficulties stem from changes in speech production that occur when hearing protectors are worn. To address this possibility, overall and one-third-octave-band SPL measurements were obtained for 16 men and 16 women as they produced connected speech while wearing foam, flange, or no earplugs (open ears) in quiet and in pink noise at 60, 70, 80, 90, and 100 dB SPL. The attenuation and the occlusion effect produced by the earplugs were measured. The Speech Intelligibility Index (SII) was also calculated for each condition. The talkers produced lower overall speech levels, speech-to-noise ratios, and SII values, and less high-frequency speech energy, when they wore earplugs compared with the open-ear condition. Small differences in the speech measures between the talkers wearing foam and flange earplugs were observed. Overall, the results of the study indicate that talkers wearing earplugs (and consequently their listeners) are at a disadvantage when communicating in noise.     

Approximation in multiscale modelling of microstructure evolution in shape-memory alloys

Various models of microstructure in deformation gradient and its evolution arising in martensitic mechanically-induced isothermal phase transformation are surveyed and scrutinized, focusing on over-bridging of various scales of the problem and its numerical approximation. In particular, numerically efficient model of a relaxed problem is shown to be approximated by conventional but computationally less efficient model based on standard partial differential inequalities.     

The xraylib library for X-ray–matter interactions. Recent developments

This work presents the recent developments of xraylib, an ANSI C library that provides convenient access to a large number of X-ray related databases, with a focus on quantitative X-ray fluorescence applications. The enhancements include improved X-ray fluorescence production cross sections that take into account cascade effects and M-lines, as well as revised line energies, atomic level widths, Compton broadening profiles etc. A full overview of the complete application programming interface is presented.     

Mild Solutions to Time Fractional Stochastic 2D-Stokes Equations with Bounded and Unbounded Delay

Journal of Dynamics and Differential Equations - In this paper, the well-posedness of stochastic time fractional 2D-Stokes equations of order $$\alpha \in (0,1)$$ containig finite or infinite delay...     

Stochastic estimation of flow near the trailing edge of a NACA0012 airfoil

A stochastic estimation technique has been applied to simultaneously acquired data of velocity and surface pressure as a tool to identify the sources of wall-pressure fluctuations. The measurements have been done on a NACA0012 airfoil at a Reynolds number of Re _c  = 2 × 10⁵, based on the chord of the airfoil, where a separated laminar boundary layer was present. By performing simultaneous measurements of the surface pressure fluctuations and of the velocity field in the boundary layer and wake of the airfoil, the wall-pressure sources near the trailing edge (TE) have been studied. The mechanisms and flow structures associated with the generation of the surface pressure have been investigated. The “quasi-instantaneous” velocity field resulting from the application of the technique has led to a picture of the evolution in time of the convecting surface pressure generating flow structures and revealed information about the sources of the wall-pressure fluctuations, their nature and variability. These sources are closely related to those of the radiated noise from the TE of an airfoil and to the vibration issues encountered in ship hulls for example. The NACA0012 airfoil had a 30 cm chord and aspect ratio of 1.