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In experiment, two optical and pressure-based methods are frequently used to evaluate laminar burning velocity of a combustible mixture. In the currently reported work, the pressure-based method was utilized to find the laminar burning velocity using the measurement of pressure variations during the combustion process in a spherical bomb and analyzing them through a multi-zone quasi-dimensional model. To check the results of the method, isooctane–air mixtures were used at equivalence ratios of 0.85 and 1.0 and initial pressures of 95 and 150 kPa with 343 K initial temperature. The time history of the bomb pressure during the combustion event, initial pressure and temperature, fuel type, and equivalence ratio were applied as input to a Fortran program written by the author based on the multi-zone combustion model; and, flame radius-time, flame speed, and laminar burning velocity at different pressures and temperatures were evaluated assuming spherical flame growth. The obtained results were compared with those of some other researchers and a reasonable agreement was observed. The wall effect on the laminar burning velocity at the end of the combustion process was clearly highlighted and a reliable range of burning velocity was distinguished. The results showed that the evaluated laminar burning velocity was not reliable at the late part of the combustion process due to possible local contact of flame front and the bomb wall, the wall effect on the reacting species, flow to small crevices, and the boundary layer effect. 相似文献
304.
Doria S. Badawy Ebrahim Abdel-Galil Ezzat M. Kandeel Wahid M. Basyouni Tamer K. Khatab 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2799-2812
A combination of tetrachlorosilane and zinc chloride in dichloromethane as an efficient and ambient binary reagent to promote a one-pot amidoalkylation reaction of enolizable ketones, aromatic aldehydes with acetonitriles, or benzonitrile have been developed. The newly synthesized β-acetamidoketones 3 and β-benzamidoketones 5 were obtained in good yields. 相似文献
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Abbas Zarifkar Afsaneh Falahatpisheh Mohammad Kazem Moravvej-Farshi Ebrahim Mortazy 《光学学报》2003,23(Z1)
A comparison between intensity noise spectra and also the line shapes of gain-guided, weakly-index-guided, and strongly-index-guided semiconductor lasers are made using numerical solution of Maxwell-Bloch equations including spontaneous emission noise. 相似文献
307.
Intensity noise including Mode Partition Noise (MPN) and Mode Hopping Noise (MHN), and Phase/Frequency Noise Spectrum (FNS) are calculated for a two-mode semiconductor laser. RIN is derived considering of MPN and MHN effect. 相似文献
308.
Mediterranean Journal of Mathematics - This work is concerned with the existence and uniqueness of positive solutions to a nonlinear boundary value problem with fractional q-derivative:... 相似文献
309.
Ebrahim Hashemi 《Journal of Pure and Applied Algebra》2007,211(2):374-382
For a monoid M, we introduce M-quasi-Armendariz rings which are a generalization of quasi-Armendariz rings, and investigate their properties. The M-quasi-Armendariz condition is a Morita invariant property. The class of M-quasi-Armendariz rings is closed under some kinds of upper triangular matrix rings. Every semiprime ring is M-quasi-Armendariz for any unique product monoid and any strictly totally ordered monoid M. Moreover, we study the relationship between the quasi-Baer property of a ring R and those of the monoid ring R[M]. Every quasi-Baer ring is M-quasi-Armendariz for any unique product monoid and any strictly totally ordered monoid M. 相似文献
310.
Seyed Ebrahim Hashemi Mahmood Payehghadr Zarrin Es'haghi Hadi Kargar 《International journal of environmental analytical chemistry》2013,93(12):1148-1163
ABSTRACTIn this approach, a new carbon paste electrode modified with N,N′-bis(5-bromo-2-hydroxybenzylidene)-2,2-dimethylpropane-1,3-diamine Schiff base ligand (L) was synthesised for selective and effective determination of Hg2+ ions in aqueous environmental samples using cyclic and square wave anodic stripping voltammetric methods. First, the selective detection of mercury ion was confirmed by evaluating the stability constants of metal complexes formed between the Schiff base ligand (L) and some desired cations by conductometric measurements. Afterwards, by preparing an effective carbon paste electrode modified with L, the experimental and instrumental parameters affecting the performance of modified electrode were investigated. Square wave anodic stripping voltammograms were obtained after applying an accumulation potential ?0.5 V and accumulation time 150 s in Britton–Robinson buffer solution at pH 2.0. The optimal square wave parameters found are pulse amplitude 75 mV, frequency 50 Hz and step potential 6 mV. The procedure exhibited linear range from 0.4 to 120 μg L?1 Hg2+ with a limit of detection of 0.042 μg L?1. The proposed electrode was proved to be highly selective in the presence of various cations and anions and was successfully used for determination of mercury in tobacco and several water samples. 相似文献