Influence Of Gas Type Research Articles

Influence of Gas Type on Reactive Species Formation, Antimicrobial Activity, and Cytotoxicity of Plasma-Activated Water Produced in a Coaxial DBD Reactor

Influence of Gas Type on Reactive Species Formation, Antimicrobial Activity, and Cytotoxicity of Plasma-Activated Water Produced in a Coaxial DBD Reactor

Influence of Gas Type on Adsorption Performance of Chabazite

Chabazite is a kind of aluminosilicate with special structure. In recent years, a large number of related studies have proved that it has good CO2 adsorption performance. In this paper, the effect of gas species on the adsorption capacity of chabazite at a certain temperature was studied, and the conclusion was drawn: under the temperature of 60℃, the adsorption capacity of chabazite for N2 was 1.0 mmol/g, and the adsorption capacity for CO2 was 2.4 mmol/g, there is a relatively large difference in the adsorption capacity of these two gases.

Influence of gas type, pressure, and temperature in laparoscopy—a systematic review

Influence of gas type, pressure, and temperature in laparoscopy—a systematic review

Influence of Gas Type on the Laser Produced Graphite Plasma

Plasma graphite creation by a pulsed Nd: YAG laser with a wavelength of 1064nm to a target in vacuum in two cases (Argon, Air) with varied gas pressures and the resulting spectrum was diagnosed using optical emission spectroscopy for the wavelength range 320-740nm electron temperature Te and electron density ne Debye lengthλD , and plasma frequency f p were calculated. The results showed that increasing the pulse laser energy causes all plasma parameters of both gases under study to increase, as well as a rise in the emission line intensity. The ionization energy of target atoms determines the presence of an element’s atomic and ionic emission lines in the emission spectrum, increase in pressure decreases the electron temperature, and Debye length, also plasma frequency and electron density increase, as it has been proven that the type of gas does not affect the properties of plasma.

Effect of gas type on insulation recovery performance and repetitive breakdown stability of a corona-stabilized plasma closing switch

The corona-stabilized plasma closing switch, which utilizes the stabilization effect resulted from the movement and accumulation of corona-generated space charge to improve the repetitive performance, has a great potential in repetitive pulsed power systems. In this paper, the influence of gas type on the recovery performance and repetitive breakdown stability of a corona-stabilized plasma closing switch is investigated. The results are analyzed from the memory effect of residual plasma, the development and propagation characteristics of streamer corona, and the thermo-hydrodynamic process of discharge channel. The enhancement effect of residual plasma on corona stabilization of the subsequent breakdown in the repetitive operation of the gas gap with highly inhomogeneous electric field and strong electronegative gas is proposed. The development and propagation characteristics of streamer corona in different gases that can lead to significant differences in the corona stabilization effect of breakdown are clarified. It is also found that the gas with small molecular mass and higher gas velocity exhibits excellent insulation recovery in the gas switch with uniform fields, but displays poor repetitive performance in the corona-stabilized switch with a rod-plate electrode.

High flow nasal cannula: Influence of gas type and flow rate on airway pressure and CO2 clearance in adult nasal airway replicas

BackgroundHigh flow nasal cannula therapy is a form of respiratory support which delivers high flow rates of heated, humidified gas to the nares via specialized cannula. Two primary mechanisms of action attributed to the therapy are the provision of positive airway pressure as well as clearance of CO2-rich exhaled gas from the upper airways. MethodsPhysiologically accurate nose-throat airway replicas were connected at the trachea to a lung simulator, where CO2 was supplied to mimic the CO2 content in exhaled gas. Cannula delivered either air, oxygen or heliox (80/20%volume helium/oxygen) to the replicas at flow rates ranging from 0 to 60 l/min. Five replicas and three cannulas were compared. Tracheal pressure and CO2 concentration were continuously measured. The lung simulator provided breaths with tidal volume of 500 ml and frequency of 18 breaths/min. Additional clearance measurements were conducted for tidal volume and breathing frequency of 750 ml and 27 breaths/min, respectively. FindingsCannula flow rate was the dominant factor governing CO2 concentration. Average CO2 concentration decreased with increasing cannula flow rate, but above 30 L/min this effect was less pronounced. Tracheal positive end-expiratory pressure increased with flow rate and was lower for heliox than for air or oxygen. A predictive correlation was developed and used to predict positive end-expiratory pressure for a given cannula size as a function of supplied flow rate and occlusion of the nares. InterpretationCompared with administration of air or oxygen, administration of heliox is expected to result in similar CO2 clearance from the upper airway, but markedly lower airway pressure.

The Effects of Gas Composition on the Atmospheric Pressure Plasma Jet Modification of Polyethylene Films**supported by the Fundamental Research Funds for the Central Universities of China (Nos. JUSRP1044 and JUSRP1045), National Natural Science Foundation of China (Nos. 51203062 and 51302110), and the Cooperative Innovation Fund, Project of Jiangsu Province, China (Nos. BY2012064, BY2013015-31 and BY2013015-32)

Polyethylene (PE) films are treated using an atmospheric pressure plasma jet (APPJ) with He or He/O2 gas for different periods of time. The influence of gas type on the plasma-polymer interactions is studied. The surface contact angle of the PE film can be effectively lowered to 58° after 20 s of He/O2 plasma treatment and then remains almost unchanged for longer treatment durations, while, for He plasma treatment, the film surface contact angle drops gradually to 47° when the time reaches 120 s. Atomic force microscopy (AFM) results show that the root mean square (RMS) roughness was significantly higher for the He/O2 plasma treated samples than for the He plasma treated counterparts, and the surface topography of the He/O2 plasma treated PE films displays evenly distributed dome-shaped small protuberances. Chemical composition analysis reveals that the He plasma treated samples have a higher oxygen content but a clearly lower percentage of −COO than the comparable He/O2 treated samples, suggesting that differences exist in the mode of incorporating oxygen between the two gas condition plasma treatments. Electron spin resonance (ESR) results show that the free radical concentrations of the He plasma treated samples were clearly higher than those of the He/O2 plasma treated ones with other conditions unchanged.

Key elements of space charge compensation on a low energy high intensity beam injector

Space charge effect (SCE) along the beam line will decrease beam quality. Space charge compensation (SCC) with extra gas injection is a high-efficiency method to reduce SCE. In this paper, we will report the experimental results on the beam profile, potential distribution, beam emittance, and beam transmission efficiency of a 35 keV∕90 mA H(+) beam and a 40 keV∕10 mA He(+) beam compensated by Ar∕Kr. The influence of gas type, gas flow, and injection location will be discussed. Emphasis is laid on the consideration of SCC when designing and commissioning a high intensity ion beam injector. Based on measured data, a new definition of space charge compensation degree is proposed.

Effects of Gas Type and Hopper Pressure on the Discharge of Pulverized Coal

The influence of gas type (air and CO2) and hopper pressure (0–400 kPa) on the discharge of the pulverized coal was investigated. For aerated discharge, fluidization in the hopper is the initial state of the discharge process; the state of gas–solid fluidization affects the subsequent hopper discharging significantly. Compared to air, CO2 showed a weaker ability to fluidize the pulverized coal, and thus it was more difficult to improve the hopper discharge at atmospheric pressure. On the other hand, increasing the hopper pressure did not affect the basic discharge law but increased the discharge rate to a certain degree. In addition, with the increase of the hopper pressure, the discharge differences between the air and CO2 aeration series reduced, because the discharge rate had a larger promotion from atmospheric pressure to 400 kPa for the CO2 case.

Influence of gas type on velocity splitting of ablated particles

The transport dynamics of the ablated particles is simulated via Monte Carlo simulation. The influences of ambient gases (He, Ne, and Ar dummy gas) on velocity splitting of the ablated particles under 100 Pa are investigated. The results show that the velocity splitting appears in four types of gases. The formation times of velocity splitting of the ablated particles decrease in sequence of He, Ne, dummy gas and Ar. The influences of the mass and radius of ambient gas molecule on the velocity splitting are also investigated. The formation time of the velocity splitting decreases with mass/radius of ambient gas molecule increasing. The intensity is the smallest when the two velocity peak intensities are equal. The formation time of velocity splitting is explained by the underdamping oscillation model and the inertia fluid model. These results give a good foundation for the further study of the Si nanoparticle growth.

Effect of gas type on the fluidization and discharge characteristics of the pulverized coal

The influence of gas type (air, He, H2 and CO2) on the fluidization and discharge characteristics of the pulverized coal was investigated in this paper. It was concluded that the gas viscosity was dominant over the gas density in influencing the fluidization quality. The increase of gas viscosity improved the fluidization uniformity, delayed the visible bubbling and promoted the discharge stability. Compared with air, a higher proportion of H2 rises through the coal bed while a higher proportion of CO2 escapes through the hopper outlet during the discharge process. Experimental results show that the discharge rate increases with the addition of H2 in the whole experimental range and CO2 always corresponds to the minimum discharge rate. In spite of the very different effects produced by the various gases, the relationship between the discharge rate and the pressure difference does not change a lot. Nedderman's mode was used to predict the discharge rate, which agreed well with the experimental data with the error kept below 20% except individual points at low aeration rate.

Influence of Gas Type on the Thermal Efficiency of Microwave Plasmas for the Sintering of Metal Powders

Microwave plasmas have enormous potential as a rapid and energy efficient sintering technology. This paper evaluates the influence of both plasma atmosphere and metal powder type on the sintering temperatures achieved and the properties of the sintered powder metal compacts. The sintering is carried out using a 2.45 GHz microwave-plasma process called rapid discharge sintering (RDS). The sintering of three types of metal powder are evaluated in this study: nickel (Ni), copper (Cu) and 316L stainless steel (SS). An in-depth study of the effects of the plasma processing parameters on the sintered powder compacts are investigated. These parameters are correlated with the mechanical performance of the sintered compacts to help understand the effect of the plasma heating process. The substrate materials are sintered in four different gas discharges, namely hydrogen, nitrogen oxygen and argon. Thermocouple, pyrometer and emission spectroscopy measurements were taken to determine the substrate and the discharge temperatures. The morphology and structure were examined using scanning electron microscopy and X-ray diffraction. The density and hardness of the sintered compacts were correlated with the plasma processing conditions. As expected higher densities were obtained with powders with lower sintering temperatures i.e. nickel and copper when compared with stainless steel. Under the power input and pressure conditions used, the highest substrate temperature attained was 1,100°C for Cu powder sintered in a nitrogen atmosphere. In contrast under the same processing conditions but in an argon plasma, the temperature achieved with SS was only 500°C. The effect of the plasma gas type on the sintered powder compact chemistry was also monitored, both hydrogen and nitrogen yielded a reducing effect for the metal in contrast with the oxidising effect observed in an oxygen plasma.

Effects of gas type and temperature on fine particle fluidization

The influence of gas type (helium and argon) and bed temperature (77-473 K) on the fluidization behaviour of Geldart groups C and A particles was investigated. For both types of particles tested, i.e., Al 2O 3 (4.8 μm) and glass beads (39 μm), the fluidization quality in different gases shows the following priority sequence: Ar > He. In the same gaseous atmosphere, the particles when fluidized at an elevated temperature usually show larger bed voidages, higher bed pressure drops, and a lower u mf for the group A powder, all indicating an enhancement in fluidization quality. Possible mechanisms governing the operations of gas type and temperature in influencing the fluidization behaviours of fine particles have been discussed with respect to the changes in both gas properties and interparticle forces (on the basis of the London-van der Waals theory). Gas viscosity (varying significantly with gas-type and temperature) proves to be the key parameter that influences the bed pressure drops and u mf in fluidization of fine particles, while the interparticle forces (also varying with gas-type and temperature) may play an important role in fine-particle fluidization by affecting the expansion behaviour of the particle-bed.

Effect of gas pressure on reactive pulsed laser ablation of a silicon target

Hydrogenated silicon and silicon nitride films are synthesized by reactive pulsed laser ablation of a silicon target in hydrogen or nitrogen gas. A correlation between gas pressure and morphology or bonding configuration of deposits was investigated. With increasing gas pressure, the surface morphology abruptly changed from film to an assembly of nanoparticles at 30 Pa in hydrogen and 20 Pa in nitrogen gas. The content of Si–H and Si–N bonds in the deposits was maximized at 50 and 5 Pa in hydrogen and nitrogen gas, respectively. The influence of gas type on nanoparticle formation and reaction between silicon and ambient gas are discussed.

Dynamic Photocurrent Images of a Gas Sensing Surface

A high-speed surface photovoltage technique which uses a numerically processed parallel lock-in amplifier was applied to obtain olfactory images. This high-speed system has measurement time short enough to allow the observation of the time evolution of gas response patterns. Representative images are presented and some of their characteristic features, such as the influence of gas type and the direction of gas flow, are discussed. Possible directions for further improvement of the system are also discussed. The capability to obtain dynamic photocurrent images is an important step towards real-time visualization and further development of olfactory camera technology.

The effect of sorbed gas on the strength of coal – an experimental study

This paper examines the influence of sorbed gas type and pressure on the strength of coal. Particular attention is focused on the influence of gas type and pressures on drillability characteristics of coal and particle size distribution of drill cuttings. Drillability of coal has a strong bearing on the strength properties of coal. Based on fracture mechanics and mechanical rock cutting, weaker rocks are easier to drill and the drill cuttings produced are generally coarse in size. Accordingly a specially designed precision drill was used to drill coal samples under both normal atmospheric and confined gas pressure conditions. Indications of changes to coal strength as a result of increased sorbed gas pressure were examined by analysing the particle size distribution of the drill flushing. A laser controlled Malvern Mastersizer S particle size analyser with measuring range between 0.05 μm and 900 μm was used to study the particle size distribution. This paper demonstrates that there is a definite variation in the range of particle size distribution with particles obtained from drilling coal samples not subjected to gas pressures in comparison with those obtained from samples drilled under confined gas pressure. Gas types also have an influence. Higher proportions of coarse particles were produced when the confined gas was changed from CH4 to CO2. A change in the rate of drilling under varying confining pressure and gas type was also evident. The rate of drilling in air (at normal atmospheric conditions) was slower than at higher confining pressures. The highest drill rates were obtained with CO2 confinement.

Influence of Gas Type and Injection System on Simultanous Reduction of Soot and NOx in IDI Diesel Engine.

Modification has been made to one of the prechambers of a 4-cylinder, IDI diesel engine used to study the combustion process, for the purpose of reducing emissions. With the provisions for optical assessment of the combustion process in the prechamber, the effect of high-pressure gas injection into the prechamber during injection has been carried out. Results of this work indicate that high-pressure gas injection during combustion can affect simultaneous soot and NOx reduction with a reasonably low amount of emission of other diesel engine pollutants. An optimum chamber type is suggested based on analysis of the effect of air, argon and nitrogen injection.