Effects Of Various Gases Research Articles

Physicochemical process of non-thermal plasma at gas-liquid interface and synergistic effect of plasma with catalyst

An atmospheric-pressure plasma jet (APPJ) was directly irradiated at a gas-liquid interface under ambient conditions. The reactive oxygen species (ROS) like hydroxyl radicals (•OH), hydrogen peroxide (H2O2) and ozone (O3) and also reactive nitrogen species (RNS) such as nitrogen oxides (NOx) and nitric acid (HNO3) formed during the plasma discharge were quantified under various experimental parameters. In a chemical dosimetry method, terephthalic acid (TA) was employed for the quantification of •OH and titanium sulfate was used to quantify the H2O2. Quantitative determination of NO3− was carried out by using Ion chromatography (IC). The changes in the solution pH were studied during the plasma treatment. Strong acidification along with the production of dominant reactive nitrogen species and ozone formation were observed with air. The effect of various gases, gas flow rate, various applied voltage and catalyst were studied to optimize the experimental conditions for the best performance. The influence of catalyst Fe2+ salt, TiO2 on the formation of reactive species were studied. The efficiency of the plasma device for the degradation of crystal violet (CV) was also investigated with TiO2 and Fe2+ salt.

Effect of Selected Components on Combustion of Methane

Abstract Article discusses the effect of various gases on the combustion of methane in LGW 702 combustion engine intended for use in cogeneration unit. The measured results were evaluated for internal, performance and economic parameters of the combustion engine the ideal operating parameters can be set. The aim of the study was to assess the effect of combustible carbon monoxide and carbon dioxide and nitrogen on the parameters.

Real-Time Vision through Haze Based on Polarization Imaging

Various gases and aerosols in bad weather conditions can cause severe image degradation, which will seriously affect the detection efficiency of optical monitoring stations for high pollutant discharge systems. Thus, penetrating various gases and aerosols to sense and detect the discharge of pollutants plays an important role in the pollutant emission detection system. Against this backdrop, we recommend a real-time optical monitoring system based on the Stokes vectors through analyzing the scattering characteristics and polarization characteristics of both gases and aerosols in the atmosphere. This system is immune to the effects of various gases and aerosols on the target to be detected and achieves the purpose of real-time sensing and detection of high pollutant discharge systems under bad weather conditions. The imaging system is composed of four polarizers with different polarization directions integrated into independent cameras aligned parallel to the optical axis in order to acquire the Stokes vectors from various polarized azimuth images. Our results show that this approach achieves high-contrast and high-definition images in real time without the loss of spatial resolution in comparison with the performance of conventional imaging techniques.

Comparative study of air and argon gases between cover and absorber coil in a cylindrical solar water heater: An experimental study

In this study, the effect of various gases filling the space between the cover and the absorber coil on the thermal performance of a cylindrical solar water heater (CSWH) is experimentally investigated. Since the Prandtl number for argon gas is less than that for the air, the thermal performance of the CSWH increases. The experiments are conducted for mass flow rates of 2.5, 3, 3.5 and 4 kg/h. The results show that an increase in the flow rate leads to a decrease in the temperature difference the of water between the inlet and outlet of the coil due to reduction of the residence time of the fluid. The energy efficiency of the collector reaches its maximum at the mass flow rate until 3.5 kg/h, and then reduces at higher values of mass flow rate because the water temperature difference decreases dramatically. Hence, the optimum mass flow rate for a cylindrical collector is reported as 3.5 kg/h. The maximum energy efficiencies for argon and air are 52.14% and 48.17%, respectively. Finally, the constructed cylindrical solar water heater is also economically compared to a flat plate collector (FPC) and an electric water heater with similar thermal efficiency.

Research of the effects of various gases on cavitation-based removal of organic pollutants from distillery wastewater

The tendency to preserve water resources and rationally use natural waters promotes finding new methods and improving the existing methods of wastewater treatment. Using the phenomenon of cavitation to intensify the treatment processes we have proposed saturating the cavitation zone with various gases such as nitrogen, oxygen, and the mixture of nitrogen and oxygen in the ratio of 1:1. The study focuses on the impact of the nature of bubbled gases, both with ultrasonic treatment and without it, on the changes in the chemical oxygen demand (COD). The calculated effective rate constants for the destruction of organic compounds in distillery wastewater have proved that the highest value of 1.2 10 -4 sec -1 is achieved through bubbling nitrogen in the cavitation zone. The use of nitrogen alone allows reaching the effective rate constant value of 0.7 10 -4 sec -1 vs. 0.2 10 -4 sec -1 in case when ultrasound is used alone. The highest degree of water treatment in cavitation conditions (63 %) is achieved in the presence of nitrogen, and the lowest (38.8 %) – of the mixture of nitrogen and oxygen in the ratio of 1:1. The differences in the effects of various bubbled gases on distillery wastewater are revealed depending on the electronic excitation energy of water molecules and the formation rates of radicals H and HO that are strong oxidants of the process. It is determined that the destruction of organic impurities in distillery wastewater can be described with the use of the first-order kinetic equation. The research has confirmed the synergistic effect of the joint action of cavitation and nitrogen in the distillery wastewater treatment. The study has determined the relative series of the effects of the nature of certain gases on the cavitation treatment of distillery wastewater and proved that the most effective nitrogen dioxide can increase the degree of the wastewater treatment by 46 % compared to the effect of ultrasound alone. Given the growing problem of inadequate industrial and domestic wastewater treatment, the development of innovative technologies is particularly important. The use of the proposed cavitation technology for the treatment of wastewater from distillery plants can reduce or even completely eliminate the negative impact of contaminants on the environment.

Elemental mercury removal from syngas by nano-ZnO sorbent

Nano-ZnO sorbents synthesized by a homogeneous precipitation method were characterized by BET (Brunauer-Emmett-Teller), XRD (X-ray diffraction) as well as XPS (X-ray photoelectron spectroscopy) analysis. The adsorption of elemental mercury by nano-ZnO under nitrogen and simulated gas atmosphere was studied on a bench-scale fixed-bed apparatus. The effect of various gases on Hg0 removal performance by nano-ZnO was analyzed. The results show that the mercury removal efficiency of the nano-ZnO is relatively poor in nitrogen atmosphere. The presence of H2S promotes the Hg0 removal by nano-ZnO observably and the mercury removal efficiency can be maintained for a long time even after stopping pass into H2S. The presence of CO and H2 promote the Hg0 removal by promotion of nano-ZnO desulfurization. As the temperature increases, the formation of elemental sulfur in the surface of the nano-ZnO gradually reduces, leading to suppress the removal of Hg0.

Two relaxation time lattice Boltzmann model for rarefied gas flows

In this paper, the lattice Boltzmann equation (LBE) with two relaxation times (TRT) is implemented in order to study gaseous flow through a long micro/nano-channel. A new relation is introduced for the reflection factor in the bounce-back/specular reflection (BSR) boundary condition based on the analytical solution of the Navier–Stokes equations. The focus of the present study is on comparing TRT with the other LBE models called multiple relaxation times (MRT) and single relaxation time (SRT) in simulation of rarefied gas flows. After a stability analysis for the TRT and SRT models, the numerical results are presented and validated by the analytical solution of the Navier–Stokes equations with slip boundary condition, direct simulation of Monte Carlo (DSMC) and information preservation (IP) method. The effect of various gases on flow behavior is also investigated by using the variable hard sphere (VHS) model through the symmetrical relaxation time.

The Influence of O2, Hydrocarbons, CO, H2, NO x , SO2, and Water Vapor Molecules on Soot Combustion over LaCoO3 Perovskite

The effect of various gases (O2, hydrocarbons, CO, H2, NOx, SO2, and H2O vapor) presenting in the diesel exhaust on soot combustion using LaCoO3 as a catalytic material was investigated in this paper. A significant promotion of the combustion rate was found following a trend of 10% H2O addition > 3,000 ppm NOx > 1% H2 or 3,000 ppm C3H6 addition, while the improvement in soot oxidation due to the introduction of 3,000 ppm CO or 3,000 ppm CH4 into the reactant gas is relatively less. The wet pretreatment of LaCoO3 with 10% steam before soot oxidation hardly affects the combustion behavior. Interestingly, 10% water vapor in the reaction feed produced a significant promoting effect on combustion. In contrast, 30 ppm SO2 treating led to an obvious deactivation likely owing to the coverage of active sites by sulfate compounds.

Inactivation of Bacteria in Oil Field Injection Water by Non-thermal Plasma Treatment

Microbial pollution commonly causes serious pipe corrosion in oil field injection water system. This paper reports on the application of non-thermal plasma to inactivate bacteria in oil filed injection water. As an efficient inactivation technology, pulsed streamer discharge plasma method injects energy into solution through a plasma channel formed by discharge between electrodes and produces various active species in solution with physical effects (electric field, UV etc.) occurring. Saprophytic bacteria, iron bacteria and sulfate reducing bacteria are used as target. The effects of various gases bubbling (oxygen, nitrogen and air) as well as aeration intensity are investigated. Experimental results show that the inactivation efficiency is greatly enhanced by gas bubbling. After 150 s discharge with oxygen bubbling (667 m3 (m3 h)−1), the inactivation efficiencies of saprophytic bacteria, iron bacteria and sulfate reducing bacteria achieve 1.85, 4.51 and 5.70 log reduction, respectively. The possible mechanism of bacteria inactivation is also discussed.

Mass spectrometric study of various coated targets utilizing the PUPR Mirror/Cusp plasma machine for the NASA Solar Probe space mission

The NASA Solar Probe space mission will be a historic operation, flying for the first time into one of the last unexplored regions of the solar system, the Sun's atmosphere or corona; hopefully revolutionizing our knowledge of the physics of the origin and evolution of the solar wind phenomenon. The spacecraft's most prominent feature is the thermal protection system (TPS), composed of a large carbon–carbon conical shield, designed to withstand the Sun's violent temperatures. Thermal testing will be conducted on various coatings on the carbon–carbon targets in order to study mass loss components using mass spectrometry. Mass spectrometry is an analytical technique used to measure the mass-to-charge ratio of ions. It is more generally used to find the composition of a physical sample by generating a mass spectrum representing the masses of sample components. By using a quadrupole mass spectrometer, the effects of plasma on various coated targets were analyzed and the effects of various gases on the plasma were studied on the PUPR Mirror/Cusp (M/C) plasma machine. A series of five tests was performed for this experiment; the first four tests consist of creating plasma with four different gases, and studying the effects of each gas on the plasma using mass spectrometry, in order to decide which plasma resembles the Sun's atmosphere or corona. The fifth test consists of introducing various coated targets, which represent the spacecraft's shield, inside the PUPR M/C plasma machine, to study how the different coatings react with the plasma that best bears a resemblance to the Sun's atmosphere, for approximately 12 h of exposure. After studying the results for the first four tests, it is evident that each gas has a distinctive effect on the plasma. For the fifth test following the study of the mass spectrometry results, it is clear that the quadrupole mass spectrometer was able to detect mass loss components for the introduced targets, and the presence of the coatings were successfully identified inside the PUPR M/C plasma machine, therefore assisting in the shield coating selection for the solar probe aircraft.

Effect of various gases and chemical catalysts on phenol degradation pathways by pulsed electrical discharges

The processes of phenol degradation by pulsed electrical discharges were investigated under several kinds of discharge atmospheres (oxygen, argon, nitrogen and ozone) and chemical catalysts (ferrous ion and hydrogen peroxide). The temporal variations of the concentrations of phenol and the intermediate products were monitored by HPLC and GC–MS, respectively. It has been found that the effect of various gases bubbling on phenol degradation rate ranked in the following order: oxygen-containing ozone > oxygen > argon > nitrogen. The high gas bubbling flow rate was beneficial to the removal of phenol. It was found that the degradation proceeded differently when in the presence and absence of catalysts. The phenol removal rate was increased when ferrous ion was added. This considerable enhancement may be due to the Fenton's reaction. What's more, putting the chemical additives hydrogen peroxide into the reactor led to a dramatic increase in phenol degradation rate. The mechanism was due to the direct or indirect photolysis and pyrolysis destruction in plasma channel. Furthermore, the intermediate products were monitored by GC–MS under three degradation conditions. More THBs were generated under degradation conditions without gases bubbling or adding any catalyst, and more DHBs under the condition of adding ferrous ion, and more carboxylic acids under the condition of oxygen-containing ozone gas bubbling. Consequently, three distinct degradation pathways based on different conditions were proposed.

Plasma treatments of indium tin oxide anodes in carbon tetrafluorinde (CF 4)/oxygen (O 2) to improve the performance of organic light-emitting diodes

The effects of various gases employed for plasma treatments of indium–tin oxide (ITO) anode surfaces have been studied on the performance of organic light-emitting diode (OLED) devices. Compared with those using pure oxygen (O 2) or pure carbon tetrafluoride (CF 4), the plasma treatment of the ITO surface using CF 4/O 2 mixture significantly improved the OLED device performance by enhancing the hole injections from the anode. The effects of the CF 4/O 2 ratios and the pressure of the plasma treatments were also studied. X-Ray photoelectron spectroscopy (XPS) results indicated that the carbon contaminants were more efficiently removed by CF 4/O 2 mixture plasma from the ITO surface than the conventional O 2 plasma. XPS results also suggested that the fluorine bonded directly to indium or tin on the ITO surface effectively reduced the hole injection barrier, improving the device performance.

The evolution of microstructure and surface bonding in SiO 2 aerogel film after plasma treatment using O 2, N 2, and H 2 gases

In this work, we investigated the effects of various gases (O 2, N 2, and H 2) plasma treatment on SiO 2 aerogel films in order to strengthen the film and improve the surface chemical bonding nature of the film. The plasma treatments could reduce the density of silanol (SiOH) and ethoxy (SiOR) groups. The physical, chemical, and electrical properties of SiO 2 aerogel film through curing with various plasma gases were evaluated. The modification of SiO 2 aerogel film by plasma gas treatment was related to the physical impingement effect of ions, chemical reaction, and irradiated vacuum UV.

Erratum to: Effect of various gases on the column flotation of fine coal

The correct authors should have been: A. Raichur, X.H. Wang and B.K. Parekh. A. Raichur is now with the Indian Institute of Science, Bangalore, India; and X.H. Wang is now group leader with BetzDearborn Paper Process Group. Jacksonville, FL.

Nonbiological Complete Differentiation of the Enantiomeric Isomers of Amino Acids and Sugars by the Complexes of Gases with the Eutectic Compounds of Alkali Chlorides and Water

We have found that eutectic compounds of sodium chloride and water form complexes with oxygen, hydrogen sulfide and carbon dioxide in the aqueous 0.1 M NaCl solution. The oxygen complex differentiates between the enantiomeric isomers of amino acids and sugars. The direction of this differentiation agrees with that of biological systems in nature where only the L-isomers of amino acids are used to form proteins, while D-form sugars form polysaccharides. These results represent the first complete differentiation of enantiomeric isomers in an inorganic system, and were achieved without the aid of any in vivo biomaterials, such as enzymes. Other alkali chlorides were also examined. The eutectic compound of potassium chloride and water forms a similar oxygen complex which also differentiates the isomers of amino acids and sugars. However, the direction of this differentiation is opposite that in the case of sodium chloride. These results call for the special attention to the fact that the concentration of potassium ions in living cells is higher than that of sodium ions. The mechanism of these observations is not yet clear, but is likely to involve the structure of an aqueous solution of a specific concentration (0.1 M) of salt. The effects of various gases were also examined. Like oxygen, hydrogen sulfide also forms a complex with the eutectic compound of sodium chloride and water. This complex differentiates the isomers of amino acids and sugars in a similar manner to the way the oxygen complex dose. This finding suggests that the enantiomeric isomers of amino acids and sugars could be differentiated in an inorganic environment. Carbon dioxide also forms a complex with the eutectic compound of sodium chloride and water, but does not differentiate the isomers.

Effect of various gases on the column flotation of fine coal

Column flotation has proven to be the most effective technique for the flotation and recovery of ultrafine coal. The commercial application of columns in the coal industry is steadily increasing (Parekh et al., 1990; Yoon et al., 1992). For the flotation of coal or mineral air is used for generating bubbles. Using a conventional flotation cell, Miller and Mishra (1985) compared froth flotation behavior of fine coal using air, nitrogen and carbon dioxide gas. They concluded that carbon dioxide gas provided a higher rate of recovery and a lower ash content. The objective of the present study was to investigate the effect of various gases such as compressed air, nitrogen, argon, and carbon dioxide on the column flotation of fine coal.

Sealed mini-chamber of variable depth for direct observation and extended evaluation of sperm motility under the influence of various gases

A new chamber for microscopical observation of living cells, e.g. spermatozoa, under hermetically sealed conditions and over an extended period is described. Motile spermatozoa were serially observed for several hours and the effect of various gases on sperm motility has been studied. The chamber could also be used to study the effect of various toxic gases in the fields of microbiology and toxicology.

Tribochemical Effects of Various Gases and Water Vapor on Thin Film Magnetic Disks With Carbon Overcoats

Friction tests on thin film magnetic disks with carbon overcoats were performed using commercial read/write heads as sliders. The results provide evidence that the thin film overcoats wear through chemical means in the presence of gaseous oxygen, and through mechanical means in the absence of oxygen. When small concentrations of water are present, friction behavior resembling that of an oxidizing environment is observed, suggesting oxidation of the carbon film preceded by dissociation of adsorbed water.

家禽の死後硬直に関する生理学的研究:各種ガス処理の影響

家禽の死後硬直に関する生理学的研究:各種ガス処理の影響

The effect of gases on the emission currents from metallic micropoints in ultra-high vacuum

The effect of various gases on prebreakdown electron emission in vacuum is studied from metallic micropoints and with gas compositions that are typical of ultra-high-vacuum systems. It was found that the presence of the gas changes preferentially the pre-exponential factor of the Fowler-Nordheim characteristics, which is related to the size of the emitting surface. The observed phenomena indicate that the combined action of several gases may create a dynamical system of adsorption and desorption leading to characteristic effects (instabilities, deviation from linearity of the Fowler-Nordheim plots, unrealistic values of the field enhancement factor) which are often ascribed to nonmetallic functions. Thus, metallic micropoints which occur in extended cathodes after sparking or arcing are possible candidates as emission sites. Since minute breakdowns are not always detectable, this statement may also hold for situations where the electrodes are thought to be virgin.