Stop Voicing and F0 Perturbation in Pahari

The present study has been carried out to investigate the perturbation effect of the voicing of initial stops on the fundamental frequency (F0) of the following vowels in Pahari. Results show that F0 values are significantly higher following voiceless unaspirated stops than voiced stops. F0 contours indicate an initially falling pattern for vowel [a:] after voiced and voiceless unaspirated stops. A rising pattern after voiced stops and a falling pattern after voiceless unaspirated stops is observed after [i:] and [u:]. These results match Umeda (1981) who found that F0 of a vowel following voiceless stops starts high and drops sharply, but when the vowel follows a voiced stop, F0 starts at a relatively low frequency followed by a gradual rise. The present data show no statistically significant difference between the F0 values of vowels with different places of articulation. Place of articulation is thus the least influencing factor.

Effective π-electron number and Symmetry Perturbation Effect on the Two-photon Absorption of Oligofluorenes

Fluorene-based molecules present significant nonlinear optical responses, multiphoton absorption in the visible, which, combined with the high fluorescence quantum yield in organic solvents, could make this class of materials potentially...

Quantitative Experimental Investigation on the Flow Characteristics of Nanofluids in Turbulent Flow

In addition to the increase of thermal conductivity, heat transfer enhancement mechanism for nanofluids also includes the changes of the flow characteristics, therefore it is needed to take an in-depth research on nanofluids flow characteristics. In this paper, the flow characteristics of H2O and SiO2-H2O nanofluids in a rectangular convex channel (channel composed of continuous staggered rectangular convex platform) at the Reynolds numbers 2300, 2500, 3000 and 4000 are studied by the quantitative PIV method (Fig. 1a). The rectangular convex channel (Fig. 1b) has periodic perturbation effect on the fluid flow, so that the flow direction is changed for several times, and vortexes are generated, which makes turbulence enhanced. In this way, flow is in the intense turbulent state under a low flow rate. Results show that the flow fields becomes more chaotic by the addition of nanoparticles (Fig. 2 and 3). Both the number and the size of vortices increase observably. The vorticity of nanofluids is also enhanced compared with H2O, and with the increase of Reynolds number, the increased ratio in the vorticity magnitude is getting higher (Fig. 4). At different Reynolds number, the pressure loss of nanofluids increases by 2.27%, 2.23%, 1.5% and 14.7%, respectively. As shown the flow resistance does not increase significantly compared to base fluids, especially at low Reynolds number. It can be concluded that the interaction between nanoparticles and the basic fluid strengthens the flow field disturbance, which is benefit to the heat transfer of nanofluids.

Design of Digital Filter by Differential Evolution

This methodology for stable and robust design of FIR filters. Differential evolution (DE) is taken as a global search technique and it uses local search algorithm to find the optimal solution for the design. DE is implemented here to design low pass, band pass as well as high order filters and results which are obtained can also be applied to higher order filters. The recombination approach involves the creation of new candidate solution components based on the weighted difference between two randomly selected population members added to a third population member. This perturbs population members relative to the spread of the broader population. In conjunction with selection, the perturbation effect self-organizes the sampling of the problem space, bounding it to known areas of interest