Slow-light switching in nonlinear Bragg-grating coupler

We study propagation and switching of slow-light pulses in nonlinear couplers with phase-shifted Bragg gratings. We demonstrate that power-controlled nonlinear self-action of light can be used to compensate dispersion-induced broadening of pulses through the formation of gap solitons, to control pulse switching in the coupler, and to tune the propagation velocity.Comment: 3 pages, 4 figure

Experimental and Modeling Investigation of the Effectof H2S Addition to Methane on the Ignition and Oxidation at High Pressures

The autoignition and oxidation behavior of CH₄/H₂S mixtures has been studied experimentally in a rapid compression machine (RCM) and a high-pressure flow reactor. The RCM measurements show that the addition of 1% H₂S to methane reduces the autoignition delay time by a factor of 2 at pressures ranging from 30 to 80 bar and temperatures from 930 to 1050 K. The flow reactor experiments performed at 50 bar show that, for stoichiometric conditions, a large fraction of H₂S is already consumed at 600 K, while temperatures above 750 K are needed to oxidize 10% methane. A detailed chemical kinetic model has been established, describing the oxidation of CH₄ and H₂S as well as the formation and consumption of organosulfuric species. Computations with the model show good agreement with the ignition measurements, provided that reactions of H₂S and SH with peroxides (HO₂ and CH₃OO) are constrained. A comparison of the flow reactor data to modeling predictions shows satisfactory agreement under stoichiometric conditions, while at very reducing conditions, the model underestimates the consumption of both H₂S and CH₄. Similar to the RCM experiments, the presence of H₂S is predicted to promote oxidation of methane. Analysis of the calculations indicates a significant interaction between the oxidation chemistry of H₂S and CH₄, but this chemistry is not well understood at present. More work is desirable on the reactions of H₂S and SH with peroxides (HO₂ and CH₃OO) and the formation and consumption of organosulfuric compounds

Nonlinear optics and light localization in periodic photonic lattices

We review the recent developments in the field of photonic lattices emphasizing their unique properties for controlling linear and nonlinear propagation of light. We draw some important links between optical lattices and photonic crystals pointing towards practical applications in optical communications and computing, beam shaping, and bio-sensing.Comment: to appear in Journal of Nonlinear Optical Physics & Materials (JNOPM

Experimental and kinetic study on ignition delay times of methane/hydrogen/oxygen/nitrogen mixtures by shock tube

This study aims (1) to analyze the performances among regencies/ cities in Jambi Province, and (2) to categorize the regencies/ cities in Jambi Province based on economic, human resources, and infrastructure development performances. Datas used in this study are secondary data of 2009-2012 from Statistics Indonesia, consists of eight component indicators to assess the performance of economic development, the five component indicators to assess the performance of the components of human resources development, and eight component indicators to assess the performance of infrastructure development. The analytical method used to achieve the objectives of the first research purposes is principal component analysis (PCA) which followed by factor analysis and to achieve the third purpose is cluster analysis. The results showed that (1) Jambi City is ranked first in the overall development performance, followed by of Tanjab Barat and Batang Hari Regencies, (2) four clusters of regencies/ cities in Jambi Province are formed based on the performance of development, namely: cluster I (Kerinci, Merangin, and Tebo Regencies) have lower performance of regional development, cluster II (Tanjab Timur Regency) has average to high performance of regional development, cluster III (Sarolangun, Batang Hari, Muaro Jambi, Tanjab Barat, Bungo Regencies, and Sungai Penuh City) have average performance of regional development, and cluster IV (Jambi City) has high performance of regional development