scholarly journals Application of an electronegative gas as a third component of the working gas in the Geiger-Mueller counter

2018 ◽  
Vol 33 (3) ◽  
pp. 268-274 ◽  
Author(s):  
Luka Perazic ◽  
Cedomir Belic ◽  
Dalibor Arbutina
Keyword(s):  
Dead Time ◽  
Gas Mixtures ◽  
Operating Point ◽  
Gas Mixture ◽  
Electric Discharges ◽  
Tube Model ◽  
The Third ◽  
Similarity Law ◽  
Font Color

In this paper, the application of three-component gas mixtures as a working gas in Geiger-Mueller tubes was considered. In addition to the noble and quenching gas, an electronegative gas is used, at the same time, as the third component of gas mixture. This paper is mostly experimental. The experiments are carried out on the enlarged Geiger-Mueller counter tube model. By applying the similarity law for electric discharges in gases on the model and commercial Geiger-Mueller counting tubes, the model was verified. The obtained results showed that a small percentage of SF6 gas, in the working gas, stabilize operating point of Geiger-Mueller counter tubes and reduce dead time. <br><br><font color="red"><b> This article has been corrected. Link to the correction <u><a href="http://dx.doi.org/10.2298/NTRP1804417E">10.2298/NTRP1804417E</a><u></b></font>

Composition of Mixtures of Natural Gas Components Determined by Raman Spectrometry

1980 ◽  
Vol 34 (4) ◽  
pp. 411-414 ◽  
Author(s):  
Dwain E. Diller ◽  
Ren Fang Chang
Keyword(s):  
Natural Gas ◽  
Mole Fraction ◽  
Gas Mixtures ◽  
Spectrometric Method ◽  
Gas Mixture ◽  
Raman Intensity ◽  
Raman Spectrometry ◽  
Intensity Measurements ◽  
Hydrocarbon Gas ◽  
Related Line

The feasibility of using Raman spectrometry for determining the composition of mixtures of natural gas components was examined. Raman intensity measurements were carried out on eight, gravimetrically prepared, binary gas mixtures containing methane, nitrogen, and isobutane at ambient temperature and at pressures to 0.8 MPa. The repeatability of the molar intensity ratio, ( I2/ y2)/( I1/ y1), where y1 is the concentration of component 1 in the mixture, and I1 is the intensity of the related line in the mixture spectrum, was examined. The compositions of two gravimetrically prepared methane-nitrogen-isobutane gas mixtures were determined spectrometrically with an estimated precision of about 0.001 in the mole fraction. Typical differences from the gravimetric concentrations were less than 0.002 in the mole fraction. The Raman spectrum of a gravimetrically prepared, eight component, hydrocarbon gas mixture was obtained to show that the Raman spectrometric method has potential for being applicable to natural gas type mixtures.

scholarly journals Phytocenological research into the meadow associations on forest hunting grounds of Serbia

2010 ◽  
Vol 62 (2) ◽  
pp. 363-372
Author(s):  
Zorica Tomic ◽  
Zorica Bijedic ◽  
Dragica Vilotic ◽  
D.P. Gacic
Keyword(s):  
Life Form ◽  
Floristic Composition ◽  
The Third ◽  
Font Color

The floristic composition of meadow associations within the fenced areas of forest hunting grounds was investigated in the spring of 2008 at three sites: Karakusa (Srem), Miloseva voda (Mt. Sokolovica) and Lomnicka reka (Mt. Veliki Jastrebac), Serbia. At the first location three associations were determined (Agrostio-Juncetum effusi Cinc.1959., Trifolio-Agrostietum stoloniferae L. Mark.1973., and Agrostietum vulgaris. Z. Pavl. 1955 sensu lato.); at the second location Festuco-Agrostietum Horv. (1952) 1982. em Trinajest. 1972., and at the third location Agrostio-Festucetum valesiacae Gajic 1961. Hemicryptophytes were the dominant life form in all the sites (ranging from 61.1 to 72.9%). Also, the presence of 24 floral elements was recorded. The largest number of floral elements was determined at the site of Mt. Sokolovica (17), and the lowest at the third site, Mt. Veliki Jastrebac (9). <br><br><font color="red"><b> This article has been corrected. Link to the correction <u><a href="http://dx.doi.org/10.2298/ABS1801217E">10.2298/ABS1801217E</a><u></b></font>

scholarly journals Molecular Simulations of CO2/CH4, CO2/N2 and N2/CH4 Binary Mixed Hydrates

2021 ◽  
Vol 83 (3) ◽  
pp. 372-378
Author(s):  
A. A. Sizova ◽  
S. A. Grintsevich ◽  
M. A. Kochurin ◽  
V. V. Sizov ◽  
E. N. Brodskaya
Keyword(s):  
Carbon Dioxide ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Gas Hydrates ◽  
Molecular Simulations ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
Grand Canonical Monte Carlo ◽  
Multicomponent Gas ◽  
Grand Canonical

Abstract Grand canonical Monte Carlo simulations were performed to study the occupancy of structure I multicomponent gas hydrates by CO2/CH4, CO2/N2, and N2/CH4 binary gas mixtures with various compositions at a temperature of 270 K and pressures up to 70 atm. The presence of nitrogen in the gas mixture allows for an increase of both the hydrate framework selectivity to CO2 and the amount of carbon dioxide encapsulated in hydrate cages, as compared to the CO2/CH4 hydrate. Despite the selectivity to CH4 molecules demonstrated by N2/CH4 hydrate, nitrogen can compete with methane if the gas mixture contains at least 70% of N2.

Oxygen Effect in Diamond Deposition at Low Temperatures

1989 ◽  
Vol 162 ◽  
Author(s):  
Y. Liou ◽  
A. Inspektor ◽  
R. Weimer ◽  
D. Knight ◽  
R. Messier
Keyword(s):  
Thin Films ◽  
Low Temperatures ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Gas Mixtures ◽  
Diamond Growth ◽  
Oxygen Effect ◽  
Gas Mixture ◽  
Diamond Thin Films ◽  
Deposited Films

ABSTRACTDiamond thin films were deposited on different substrates at low temperatures (lowest temperature∼ 300°C, estimated) in a microwave plasma enhanced chemical vapor deposition (MPCVD) system. The deposited films were amorphous carbon or diamond films depending on the different gas mixtures used. The growth rate of diamond thin films was decreased by adding oxygen to the gas mixture. The addition of oxygen to the gas mixtures was found to be important for diamond growth at low temperatures. Different concentrations of oxygen have been added into the gas mixture. Without oxygen, the deposited films were white soots and easily scratched off. Increasing the oxygen input improved the quality of the Raman peaks and increased the film transpancy. The diamond films were also characterized by scanning electron microscopy (SEM).

Investigation of Slider Vibrations and Vibration Mode Changes in Helium-Air Gas Mixtures

2014 ◽  
Author(s):  
Zhengqiang Tang ◽  
Frank E. Talke
Keyword(s):  
Numerical Model ◽  
Physical Properties ◽  
Free Path ◽  
Frequency Analysis ◽  
Vibration Mode ◽  
Mean Free Path ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
Air Bearing ◽  
Pitch Mode

A numerical model for the simulation of slider vibrations in helium-air gas mixtures has been developed. The physical properties of the helium-air gas mixture, such as density, mean free path and viscosity, were determined to calculate the dynamic flying characteristics of a slider using the CMRR air bearing simulator. Frequency analysis shows that the helium percentage in the gas mixture can shift the second pitch mode of the slider to a higher frequency.

A Power-Law Mixing Rule for Predicting Apparent Diffusion Coefficients of Binary Gas Mixtures in Heavy Oil

2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Hyun Woong Jang ◽  
Daoyong Yang ◽  
Huazhou Li
Keyword(s):  
Diffusion Coefficient ◽  
Apparent Diffusion Coefficient ◽  
Heavy Oil ◽  
Diffusion Coefficients ◽  
Gas Mixtures ◽  
Gas Diffusion ◽  
Gas Mixture ◽  
Mixing Rule ◽  
Heavy Oils ◽  
Apparent Diffusion

A power-law mixing rule has been developed to determine apparent diffusion coefficient of a binary gas mixture on the basis of molecular diffusion coefficients for pure gases in heavy oil. Diffusion coefficient of a pure gas under different pressures and different temperatures is predicted on the basis of the Hayduk and Cheng's equation incorporating the principle of corresponding states for one-dimensional gas diffusion in heavy oil such as the diffusion in a pressure–volume–temperature (PVT) cell. Meanwhile, a specific surface area term is added to the generated equation for three-dimensional gas diffusion in heavy oil such as the diffusion in a pendant drop. In this study, the newly developed correlations are used to reproduce the measured diffusion coefficients for pure gases diffusing in three different heavy oils, i.e., two Lloydminster heavy oils and a Cactus Lake heavy oil. Then, such predicted pure gas diffusion coefficients are adjusted based on reduced pressure, reduced temperature, and equilibrium ratio to determine apparent diffusion coefficient for a gas mixture in heavy oil, where the equilibrium ratios for hydrocarbon gases and CO2 are determined by using the equilibrium ratio charts and Standing's equations, respectively. It has been found for various gas mixtures in two different Lloydminster heavy oils that the newly developed empirical mixing rule is able to reproduce the apparent diffusion coefficient for binary gas mixtures in heavy oil with a good accuracy. For the pure gas diffusion in heavy oil, the absolute average relative deviations (AARDs) for diffusion systems with two different Lloydminster heavy oils and a Cactus Lake heavy oil are calculated to be 2.54%, 14.79%, and 6.36%, respectively. Meanwhile, for the binary gas mixture diffusion in heavy oil, the AARDs for diffusion systems with two different Lloydminster heavy oils are found to be 3.56% and 6.86%, respectively.

scholarly journals Explosion waves and shock waves III-The initiation of detonation in mixtures of ethylene and oxygen and of carbon monoxide and oxygen

1935 ◽  
Vol 152 (876) ◽  
pp. 418-445 ◽  
Author(s):  
William Payman ◽  
H. Titman ◽  
Jocelyn Field Thorpe
Keyword(s):  
Shock Wave ◽  
Carbon Monoxide ◽  
Shock Waves ◽  
Detonation Wave ◽  
Wave Speed ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
And Shock Waves ◽  
Long Run ◽  
Detonating Gas

This series of papers has so far dealt mainly with non-maintained or partially maintained atmospheric shock waves, and only incidentally with the fully maintained "detonation" wave. It is generally accepted that the detonation wave in an explosive gas mixture is a shock wave produced by the rapid combustion of the mixture, sufficiently intense to cause almost instantaneous ignition of the gas through which it passes, and continuous maintained by the combustion thereby started. An account of some preliminary experiments, using the "wave-speed" camera to record the movement of the flame and of the invisible shock waves in front of the flame in gas mixtures prior to detonation, has already been given by one of us. Those experiments related mainly to hydrogen-oxygen and methane-oxygen mixtures whose aptitude to detonate may be regarded as moderate, for the continuation of the work, mixtures with oxygen have again been used, but a more readily detonating gas, ethylene, was chosen. Experiments were also made with carbon monoxide, because the flame usually requires a comparatively long run before detonation is established. These two gases have the advantage, not shared by hydrogen and methane, that their predetonation flames are sufficiently actinic for good records to be obtained by direct photography for comparison with corresponding "wave-speed" records. All gas mixtures used were saturated with water vapour.

On the Heat Transfer Enhancement of Turbulent Gas Floes in Short Round Tubes Engaging a Light Gas Mixed With Selected Heavier Gases

2011 ◽  
Author(s):  
Neda Mobinipouya ◽  
Omid Mobinipouya
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Free Convection ◽  
Constant Pressure ◽  
Gas Mixtures ◽  
Global Maximum ◽  
Gas Mixture ◽  
Kinetic Theory Of Gases ◽  
Gas Composition ◽  
Convection Coefficient

A unique way for maximizing turbulent free convection from heated vertical plates to cold gases is studied in this paper. The central idea is to examine the attributes that binary gas mixtures having helium as the principal gas and xenon, nitrogen, oxygen, carbon dioxide, methane, tetrafluoromethane and sulfur hexafluoride as secondary gases may bring forward. From fluid physics, it is known that the thermo-physical properties affecting free convection with binary gas mixtures are viscosity ηmix, thermal conductivity λmix, density ρmix, and heat capacity at constant pressure. The quartet ηmix, λmix, ρmix, and Cp,mix is represented by triple-valued functions of the film temperature the pressure P, and the molar gas composition w. The viscosity is obtained from the Kinetic Theory of Gases conjoined with the Chapman-Enskog solution of the Boltzmann Transport Equation. The thermal conductivity is computed from the Kinetic Theory of Gases. The density is determined with a truncated virial equation of state. The heat capacity at constant pressure is calculated from Statistical Thermodynamics merged with the standard mixing rule. Using the similarity variable method, the descriptive Navier-Stokes and energy equations for turbulent Grashof numbers Grx > 109 are transformed into a system of two nonlinear ordinary differential equations, which is solved by the shooting method and the efficient fourth-order Runge-Kutta-Fehlberg algorithm. The numerical temperature fields T(x, y) for the five binary gas mixtures He-Xe, He-N2, He-O2, He-CO2, He-CH4, He-CF4 and He-SF6 are channeled through the allied mean convection coefficient hmix/B varying with the molar gas composition w in proper w-domain [0, 1]. For the seven binary gas mixtures utilized, the allied mean convection coefficient hmix/B versus the molar gas composition w is graphed in congruous diagrams. At a low film temperature Tf = 300 K, the global maximum allied mean convection coefficient hmix,max/B = 85 is furnished by the He-SF6 gas mixture at an optimal molar gas composition wopt = 0.93. The global maximum allied mean convection coefficient hmix,max/B = 57 is supplied by pure methane gas SF6 (w = 1) at a high film temperature Tf = 1000 K instead of the He-SF6 gas mixture.

Enhancement of O-atom density through collisions with Ne by laser-produced plasma in Ne–O2 gas mixtures and possible energy transfer mechanism

2019 ◽  
Vol 33 (18) ◽  
pp. 1950198
Author(s):  
Muhammad Ibrahim Khan ◽  
Muhammad Aslam Khan ◽  
Muhammad Iqbal Zaman ◽  
Najeeb ur Rehman ◽  
Asad Masood ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Laser Energy ◽  
Focal Length ◽  
Gas Mixtures ◽  
Transfer Mechanism ◽  
Gas Mixture ◽  
Energy Transfer Mechanism ◽  
Stark Broadening ◽  
Line Intensities ◽  
Laser Produced Plasma

Laser-produced plasma in Ne and O2 gases and Ne–O2 gas mixture with different O2 fractions have been investigated. The plasma were produced by focusing a laser beam of 5 ns pulse duration from a Nd:YAG laser ([Formula: see text] = 1064 nm) through a lens of 5 cm focal length into the chamber filled with different gas species at different pressures. Possible enhancement in O-atom densities through collisions with metastable Ne atoms by the laser-created plasma in Ne–O2 gas mixtures and possible energy transfer mechanism was studied. Study of energy transfer through collisions was carried out by comparisons of the line intensities of the emitted spectra from laser-created plasma in gas mixtures and pure gases with the technique of optical emission spectroscopy (OES). Strong evidence of energy transfer from Ne to O was recorded. From the result, it was suggested that the high-lying metastable levels of Ne were responsible for enhancement of O-atoms density in gas mixture and Ne also play important role in energy transfer mechanism through collision. Also, behaviors of the line intensities under different laser energies were studied. Behaviors of line intensities and line widths were the main parameters measured. Stark broadening of lines in Ne with different laser energies was recorded. The electron temperature T[Formula: see text] and number density N[Formula: see text] were found to be 1.01 eV and 9.44 × 10[Formula: see text] cm[Formula: see text] in Ne at different laser energy/pulse with total pressure of 1000 mbar.

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