Search

The article is devoted to the lyrics linguistic examination of the song “We don’t wanna put in” that was to have been the Georgian entry to the Eurovision Song Contest 2009. The purpose of the research was to ascertain the presence of verbal violations of the Contest in the lyrics. The methods of description, text interpretation and discourse analysis of the lyrics enabled package treatment of the song authors’ intentions, finding the linguistic manipulation methods, the conclusion that confirmed the theoretical hypothesis suggested in this paper.

In this paper, a methodology for experimental investigation of chemical and thermal structure of weakly stretched counterflow flames under terrestrial conditions is proposed. The non-premixed counterflow flames are stabilized in a narrow channel between quartz plates, and the flame gases are sampled by a microprobe inserted via a thin slit in one of the quartz plates. The gas samples are then analyzed by mass spectrometry. The results of the measurements of mole fraction profiles of the main components of methane-air non-premixed flames, namely, CH4, O2, H2O, CO2, and CO, are presented. The temperature profiles are also reconstructed using the measurement data for the gas composition. The experimental profiles are compared to the results of the 3D numerical simulations undertaken within the global reaction mechanisms (one- and four-step) and a detailed reaction mechanism (San-Diego). The results of this work clearly show that the thermal and chemical structures of the counterflow flame in the planar channel are essentially non-one-dimensional, and 3D-calculations are necessary to correctly predict the flame behavior in this configuration. The methodology demonstrated in the current work can be successfully employed for the investigation of the low stretched counterflow flames of various hydrocarbon fuels and fuel blends. This will allow verifying and developing the reaction kinetic models capable of quantitative prediction of weakly stretched flame behavior in confined conditions. [ABSTRACT FROM AUTHOR]

In the present paper, the laminar burning velocity and structure of near-stoichiometric premixed laminar flames of methyl methacrylate (MMA) with and without trimethylphosphate (TMP) additives have been studied experimentally and by numerical modeling. The MMA+TMP combustion system is considered as a model system, which simulates gas-phase combustion of polymethyl methacrylate (PMMA) with additive of phosphorus-containing fire retardants (PFRs). The motivation of the present research is to provide a basis for development of a predictive gas-phase chemical kinetic model for inhibition of PMMA by PFRs. The flame sampling molecular beam mass spectrometry was used to determine the spatial variation of the mole fractions of H, OH, PO, PO 2 , HOPO, HOPO 2 and some intermediate hydrocarbons in the one-dimensional burner-stabilized flames. The effect of TMP on the hydrocarbon intermediates in the flames is investigated. The reaction mechanism for combustion of MMA+TMP system has been validated against the novel laminar burning velocity and chemical speciation data. Performances and deficiencies of the kinetic mechanism for MMA flame inhibition are discussed. The sensitivity analysis showed that the insufficiently accurate prediction of mole fraction of H, O and OH results in disagreement for mole fraction profiles of hydrocarbon intermediates in the inhibited flame. Inhibition effectiveness of MMA flame by TMP is compared with that derived from experimental data for other fuels and the observed tendencies are discussed. [ABSTRACT FROM AUTHOR]

Abstract: The flame structure of the premixed H2/O2/Ar mixture (13%/14.5%/72.5%vol.) with and without 0.12vol.% of titanium tetraisopropoxide (Ti(OC3H7)4) has been studied experimentally using the flame-sampling molecular beam mass-spectrometry and the microthermocouple techniques. The flame was stabilized on a flat burner at 1atm. The temperature and concentration profiles for Н2, О2, H2O, and Ti(OC3H7)4 have been measured. The mass peak intensity profiles of the titanium-containing species TiO2, HTiO2, TiO, HTiO, Ti, TiH, Ti2O3, TiO3 have been measured as well. The experimental results were analyzed using kinetic modeling and quantum chemical calculations. It was established that hydrolysis of Ti(OC3H7)4 is the dominating primary reaction of its decomposition in the flame. The rate constant of hydrolysis was estimated to be k =2×1012 exp(−6160/T)mol−1 cm3 s−1. The results of quantum chemical computations support this conclusion. On the basis of concentration profiles of the Ti-containing intermediates, the schematic mechanism of the Ti(OC3H7)4 conversion in the flame has been proposed. [Copyright &y& Elsevier]

Abstract: The applicability of molecular beam mass spectrometry (MBMS) in studying the structure of counterflow flames has been tested by investigating a counterflow flame of CH4/N2 and O2/N2. The thermal structure of the flame was examined using a microthermocouple; the concentration profiles of such stable species as CH4, O2, and CO2 were measured by sampling with a microprobe and MBMS at various positions. The microprobe did not disturb the flame. However, the sonic probe, when inserted into the flame transverse to the burner axis to measure the centerline concentration profiles, produced a significant disturbance of the flame. But no such disturbance was observed when the tip of the sonic probe was located at the periphery of the burner. Good agreement was obtained between the concentration profiles of stable species, as measured using a microprobe and a sonic probe at the periphery of the burner. To verify the applicability of MBMS for detecting radicals and other labile species in a counterflow flame, the concentration profiles of H, OH, and the main phosphorus-bearing species in the counterflow flame doped with trimethylphosphate (TMP) were measured by MBMS at the periphery of the burner and compared with results of modeling using the OPPDIF code and a mechanism for the combustion of TMP, tested previously in premixed flames of methane and oxygen with TMP as an additive. Good agreement was obtained between the measured and simulated concentration profiles for the reagents, as well as for the final and intermediate products with relatively high molecular weights (PO, PO2, HOPO, HOPO2). The measured concentration profiles of species with low molecular weights (H2O, CO2, OH, H) were found to be broader than the calculated ones—in fact, the lower the molecular weight, the wider was the profile. This is probably due to a real flame not being one-dimensional. [Copyright &y& Elsevier]

Abstract: The mechanism of flame inhibition by phosphorus-containing species (PCSs) is known to involve their effect on the recombination of atoms and free radicals in flames. Chemical inhibition of laminar atmospheric methane/oxygen flames by trimethylphosphate over a range of equivalence ratio has been studied experimentally, using the heat flux method for measurement of burning velocity and molecular beam mass spectrometry for measurement of concentration profiles of both stable and labile species, and with numerical modeling using detailed chemical kinetic reaction mechanisms. Concentrations of H and OH in flames with and without the inhibitor were obtained by measurements and modeling. The addition of the inhibitor reduces the maximum concentrations of H and OH (in the reaction zone) in the lean and rich flame. This reduction is much larger in the rich flame than in the lean one. The concentration profiles of PCSs—PO, PO2, HOPO, HOPO2, and H3PO4 were measured and simulated for rich and lean flames stabilized on a flat burner. According to flame speed measurements for inhibited CH4/air flames over a range of ϕ, the inhibition effectiveness E i increases in the range of ϕ =0.8–1.2 and then decreases with a further increase of ϕ. The increase in E i in the range ϕ =0.7–1.2 is attributed to a change of PCSs composition. The reduction in E i for ϕ >1.2 can be explained by a decrease in the concentration of active PCSs due to an increase in the concentration of inactive species, such as CH3PO2 and other products of incomplete combustion of TMP. The inhibition effectiveness E i versus ϕ correlates with change of H and OH concentration at addition of TMP in flame. Validation of the previously developed model for inhibition by PCSs has shown that in spite of some discrepancies it adequately describes many experimental results. [Copyright &y& Elsevier]

Abstract: Flat premixed burner-stabilized H2 +O2 +N2 flames, neat or doped with 300–1000ppm of NO or NH3, were studied experimentally using molecular-beam mass-spectrometry and simulated numerically. Spatial profiles of temperature and concentrations of stable species, H2, O2, H2O, NO, NH3, and of H and OH radicals obtained at atmospheric pressure in lean (ϕ =0.47), near-stoichiometric (ϕ =1.1) and rich (ϕ =2.0) flames are reported. Good agreement between measured and calculated structure of lean and near-stoichiometric flames was found. Significant discrepancy between simulated and measured profiles of NO concentration was observed in the rich flames. Sensitivity and reaction path analyses revealed reactions responsible for the discrepancy. Modification to the model was proposed to improve an overall agreement with the experiment. [Copyright &y& Elsevier]