Determination of toxicity of a gas or gas mixture

A model for unsteady droplet vaporization is presented that considers the droplet temperature range from flash-boiling conditions to normal evaporation. The theory of continuous thermodynamics was used to model the properties and compositions of multicomponent fuels such as gasoline. In order to model the change of evaporation rate from normal to boiling conditions more realistically, an unsteady internal heat flux model and a new model for the determination of the droplet surface temperature is proposed. An explicit form of the equation to determine the heat flux from the surrounding gas mixture to the droplet-gas interface was obtained from an approximate solution of the quasi-steady energy equation for the surrounding gas mixture, with the inter-diffusion of fuel vapor and the surrounding gas taken into account. The model was applied to calculate evaporation processes of droplets for various ambient temperatures and droplet temperatures.

Download Full-text

Determination Of Gas Mixture Components Using Fluctuation Enhanced Sensing And The LS-SVM Regression Algorithm

Metrology and Measurement Systems ◽

10.1515/mms-2015-0039 ◽

2015 ◽

Vol 22 (3) ◽

pp. 341-350 ◽

Cited By ~ 29

Author(s):

Łukasz Lentka ◽

Janusz M. Smulko ◽

Radu Ionescu ◽

Claes G. Granqvist ◽

Laszlo B. Kish

Keyword(s):

Support Vector Machine ◽

Least Squares ◽

Temperature Change ◽

Nonlinear Regression ◽

Ultraviolet Irradiation ◽

Support Vector ◽

Gas Mixture ◽

Gas Concentration ◽

Single Sensor

Abstract This paper analyses the effectiveness of determining gas concentrations by using a prototype WO3 resistive gas sensor together with fluctuation enhanced sensing. We have earlier demonstrated that this method can determine the composition of a gas mixture by using only a single sensor. In the present study, we apply Least-Squares Support-Vector-Machine-based (LS-SVM-based) nonlinear regression to determine the gas concentration of each constituent in a mixture. We confirmed that the accuracy of the estimated gas concentration could be significantly improved by applying temperature change and ultraviolet irradiation of the WO3 layer. Fluctuation-enhanced sensing allowed us to predict the concentration of both component gases.

Download Full-text

Experimental Determination of the Static Equivalent Pressures of Detonative Explosions of Stoichiometric CH4/O2/N2-Mixtures and CH4/O2-Mixtures in Long Pipes

Volume 4: Fluid-Structure Interaction ◽

10.1115/pvp2016-63223 ◽

2016 ◽

Author(s):

Hans-Peter Schildberg

Keyword(s):

Experimental Data ◽

Experimental Determination ◽

Process Design ◽

Pressure Vessel ◽

Gas Mixture ◽

Detonation Pressure ◽

Recent Past ◽

Static Loads ◽

Present Experimental Data

In the recent past (PVP2013-97677, PVP2014-28197, PVP2015-45286) we had started to determine the static equivalent pressures pstat of the eight detonative pressure scenarios in long and short pipes for different detonable gas mixtures. The pstat-values are of vital importance for process design: by assigning static equivalent pressures to the highly dynamic detonative pressure peaks it is possible to apply the established pressure vessel guidelines, which can only cope with static loads, for the design of detonation pressure resistant pipes. One important finding was that the ratio R between pstat at the location where transition from deflagration to detonation occurs and pstat in the region of the stable detonation strongly depends on the reactivity of the gas mixture. In this paper we present experimental data showing the variation of R over the entire explosive range of Methane/O2/N2 mixtures. Qualitatively, the results should be representative for all other combustible/O2/N2-mixtures. Furthermore, recommendations for estimating pstat values of short pipe scenarios on basis of the long pipe scenarios are given.

Download Full-text

Method and arrangement for acoustic determination of moisture content of a gas mixture

The Journal of the Acoustical Society of America ◽

10.1121/1.2409469 ◽

2006 ◽

Vol 120 (6) ◽

pp. 3455

Author(s):

Erik Cardelius

Keyword(s):

Moisture Content ◽

Gas Mixture

Download Full-text

Effect of analyzer on determination of mixed venous PCO2 and cardiac output during exercise

Journal of Applied Physiology ◽

10.1152/jappl.1995.79.3.1032 ◽

1995 ◽

Vol 79 (3) ◽

pp. 1032-1038 ◽

Cited By ~ 8

Author(s):

L. Hornby ◽

A. L. Coates ◽

L. C. Lands

Keyword(s):

Cardiac Output ◽

Gas Mixture ◽

Arterial Pco2 ◽

Venous Pco2 ◽

The Face ◽

High O2 ◽

Collision Broadening ◽

Rebreathing Methods ◽

Mixed Venous

Cardiac output (CO) during exercise can be determined noninvasively by using the indirect Fick CO2-rebreathing technique. CO2 measurements for this technique are usually performed with an infrared analyzer (IA) or mass spectrometer (MS). However, IA CO2 measurements are susceptible to underreading in the face of high O2 concentrations because of collision broadening. We compared an IA (Ametek model CD-3A) with a MS (Marquette model MGA-1100) to see the effect this would have on mixed venous PCO2 (PVCO2) and CO measurements. After calibration with room air and a gas mixture of 5% CO2–12% O2–83% N2, both devices were tested with three different gas mixtures of CO2 in O2. For each gas mixture, IA gave lower CO2 values than did the MS (4.1% CO2: IA, 3.85 +/- 0.01% and MS, 4.13 +/- 0.01%; 9.2% CO2: IA, 8.44 +/- 0.07% and MS, 9.19 +/- 0.01%; 13.8% CO2: IA, 12.57 +/- 0.15% and MS, 13.82 +/- 0.01%). Warming and humidifying the gases did not alter the results. The IA gave lower values than did the MS for eight other medical gases in lower concentrations of O2 (40–50%). Equilibrium and exponential rebreathing procedures were performed. Values determined by the IA were > 10% higher than those determined by the MS for both rebreathing methods. We conclude that all IAs must be checked for collision broadening if they are to be used in environments where the concentration of O2 is > 21%. If collision broadening is present, then either a special high O2-CO2 calibration curve must be constructed, or the IA should not be used for both arterial PCO2 and PVCO2 estimates because it may produce erroneously low PVCO2 values, with resultant overestimation of CO.

Download Full-text

On the method of precise abundance determination of isotopologues in a gas mixture

Physical Chemistry Chemical Physics ◽

10.1039/c9cp00750d ◽

2019 ◽

Vol 21 (16) ◽

pp. 8464-8469 ◽

Cited By ~ 6

Author(s):

Oleg N. Ulenikov ◽

Elena S. Bekhtereva ◽

Olga V. Gromova ◽

Anastasia S. Belova ◽

Sigurd Bauerecker

Keyword(s):

Isotope Exchange ◽

Gaseous Mixture ◽

Gas Mixture ◽

Partial Pressures ◽

Abundance Determination

A method is presented which allows one to derive partial pressures of isotopologue molecules in a gaseous mixture under the conditions of rapid isotope exchange.

Download Full-text

Determination of Odor Intensity of Binary Gas Mixtures Using Perceptual Models and an Electronic Nose Combined with Fuzzy Logic

Sensors ◽

10.3390/s19163473 ◽

2019 ◽

Vol 19 (16) ◽

pp. 3473 ◽

Cited By ~ 1

Author(s):

Szulczyński ◽

Gębicki

Keyword(s):

Fuzzy Logic ◽

Point Of View ◽

Odor Intensity ◽

Gas Mixture ◽

Electronic Noses ◽

Practical Point ◽

Fuzzy Logic Algorithm ◽

Holistic Analysis ◽

Analyze Data

Measurement and monitoring of air quality in terms of odor nuisance is an important problem. From a practical point of view, it would be most valuable to directly link the odor intensity with the results of analytical air monitoring. Such a solution is offered by electronic noses, which thanks to the possibility of holistic analysis of the gas sample, allow estimation of the odor intensity of the gas mixture. The biggest problem is the occurrence of odor interactions between the mixture components. For this reason, methods that can take into account the interaction between components of the mixture are used to analyze data from the e-nose. In the presented study, the fuzzy logic algorithm was proposed for determination of odor intensity of binary mixtures of eight odorants: n-Hexane, cyclohexane, toluene, o-xylene, trimethylamine, triethylamine, α-pinene, and β-pinene. The proposed algorithm was compared with four theoretical perceptual models: Euclidean additivity, vectorial additivity, U model, and UPL model.

Download Full-text