Argon Gas Flow Rate Research Articles

Discharge characteristics of steady-state high-density plasma source based on cascade arc discharge with hollow cathode.

We developed a steady-state high-density plasma source by applying a hollow cathode to a cascade arc discharge device. The hollow cathode is made of a thermionic material (LaB6) to facilitate plasma production inside it. The cascade arc discharge device with the hollow cathode produced a stationary plasma with an electron density of about 1016cm-3. It was found that the plasma source produces a strong pressure gradient between the gas feed and the vacuum chamber. The plasma source separated the atmospheric pressure (100kPa) and a vacuum (100Pa) when the discharge was performed with an argon gas flow rate of 5.0 l/min and a discharge current of 40A. An analysis of the pressure gradient along the plasma source showed that the pressure difference between the gas feed and the vacuum chamber can be well described by the Hagen-Poiseuille flow equation, indicating that the viscosity of the neutral gas is the dominant factor for producing this pressure gradient. A potential profile analysis suggested that the plasma was mainly heated within cylindrical channels whose inner diameter was 3mm. This feature and the results of the pressure ratio analysis indicated that the temperature, and, thus, viscosity, of the neutral gas increased with the increasing number of intermediate electrodes. The discharge characteristics and shape of the hollow cathode are suitable for plasma window applications.

Ultra-Trace Determination of Arsenic by Platinum-Coated Tungsten Coil Hydride Generation (HG) Atomic Absorption Spectrometry (AAS)

A simple, rapid, and sensitive method for the determination of ultra-trace arsenic (III) is reported based on in situ trapping and revolatilization on a platinum (Pt) coated tungsten (W) coil atom trap. First, the analyte species in vapor form were transported by a mixture of Ar and H2 and trapped on the Pt-coated W-coil heated at 60 °C. Next, in the releasing step, the trap was resistively heated to 950 °C; the analyte species are revolatilized and transported to the quartz tube atomizer. The NaBH4 concentration, NaOH concentration, HCl concentration, trapping and releasing temperature, trapping time, and hydrogen and argon gas flow rates were optimized. Using these conditions, a limit of detection of 16 ng L−1 was obtained. The precision was evaluated by relative standard deviation corresponding to 4.8% at 1.0 μg L−1 (n = 11). The surface of the W-coil trap was coated with Pt using electrolytic deposition. Scanning electron microscopy-energy dispersive X- ray (SEM-EDX) analyses were performed to control the surface morphology of the trap. The same trap may be used for at least 350 atomization cycles without losing sensitivity. The accuracy of the proposed method was evaluated by analyzing NIST CRM 1640a (Trace Elements in Natural Water), EnviroMAT (Drinking water), and CRM-023 (Sandy Loam 7) certified reference materials. The measurements of the certified reference materials were in good agreement with the certified values at the 95% confidence level. The developed method was applied to the determination of As in drinking water samples from Muğla province.

Optimization of Atmospheric Pressure Plasma Jet with Single-Pin Electrode Configuration and Its Application in Polyaniline Thin Film Growth.

This study systematically investigated an atmospheric pressure plasma reactor with a centered single pin electrode inside a dielectric tube for depositing the polyaniline (PANI) thin film based on the experimental case studies relative to variations in pin electrode configurations (cases I, II, and III), bluff-body heights, and argon (Ar) gas flow rates. In these cases, the intensified charge-coupled device and optical emission spectroscopy were analyzed to investigate the factors affecting intensive glow-like plasma generation for deposition with a large area. Compared to case I, the intense glow-like plasma of the cases II and III generated abundant reactive nitrogen species (RNSs) and excited argon radical species for fragmentation and recombination of PANI. In case III, the film thickness and deposition rate of the PANI thin film were about 450 nm and 7.5 nm/min, respectively. This increase may imply that the increase in the excited radical species contributes to the fragmentation and recombination due to the increase in RNSs and excited argon radicals during the atmospheric pressure (AP) plasma polymerization to obtain the PANI thin film. This intense glow-like plasma generated broadly by the AP plasma reactor can uniformly deposit the PANI thin film, which is confirmed by field emission-scanning electron microscopy and Fourier transform infrared spectroscopy.

STUDY OF FLUID DYNAMICS AND SULFUR MASS TRANSFER BETWEEN STEEL AND SLAG IN A LADLE FURNACE CONSIDERING DRAG AND NON-DRAG FORCES

In this work fluid dynamics and a basic study of the sulfur transfer at the steel/slag interface in the ladle during argon gas agitation was developed. Mass transfer and chemical reaction models coupled with Computational Fluid Dynamics (CFD) were employed. The multiphasic simulation was solved using the Eulerian model considering drag and non-drag forces, and the flow pattern was validated through Particle Image Velocimetry (PIV) technique. The sulfur transfer rate was tracked by two approximations: (1) unidirectional constant rate Mass Transfer Model (MTM), and (2) unidirectional constant rate Mass Transfer Model coupled with Chemical Reaction Model (MTM+CRM) using Arrhenius equation. It was found that including the non-drag forces affects the fluid dynamics structure. Otherwise, the desulfurization rates increase as the argon gas flow rate increases, finding that the MTM model predicts ~15% less sulfur in the steel than the MTM+CRM, whose results were compared with plant measurements reports.

Study of the relationship between magnetic anisotropy and composition ratio of Fe oxide to Fe at CoFeB/MgO film interface

Ta (5)/CoFeB (1)/MgO (2)/Ta (2) (in nm) multilayers were deposited on silicon substrates by magnetron sputtering, and the MgO layer was prepared by two methods at the same argon gas flow rate: the radio frequency (RF) sputtering method of MgO target and the reactive sputtering method of direct current (DC) sputtering Mg target with introducing oxygen at the same time. The sample prepared by the former method was denoted as Sample A, and the latter was denoted as Sample B. The results indicate that as-deposited Sample A shows in-plane magnetic anisotropy (IMA) with Keff = -0.79 × 106erg/cm3. However, the as-deposited Sample B shows perpendicular magnetic anisotropy (PMA) with Keff = 1.69 × 106erg/cm3, and the Keff value increases to 3.17 × 106erg/cm3 after annealing at 250℃. X-ray photoelectron spectroscopy (XPS) results illustrate that the films show PMA when the composition ratio (ε) of Fe oxide to Fe in CoFeB/oxide interface of Sample A and B annealed below 300 ℃, is approximately in the range of 0.65–0.75. When ε is beyond the above range, the film shows IMA. Moderate oxidation state at the interface results in the formation of PMA and it was improved by forming effective orbital hybridization of Fe 3d and O 2p. High resolution transmission electron microscopy (HRTEM) analysis reveals that no crystallization appears in CoFeB and MgO layer of the film before and after annealing, and crystallization has no effect on the interface chemical states in this system.

Growth Mechanism of Periodic-Structured MoS2 by Transmission Electron Microscopy.

Molybdenum disulfide (MoS2) was grown on a laser-processed periodic-hole sapphire substrate through chemical vapor deposition. The main purpose was to investigate the mechanism of MoS2 growth in substrate with a periodic structure. By controlling the amount and position of the precursor, adjusting the growth temperature and time, and setting the flow rate of argon gas, MoS2 grew in the region of the periodic holes. A series of various growth layer analyses of MoS2 were then confirmed by Raman spectroscopy, photoluminescence spectroscopy, and atomic force microscopy. Finally, the growth mechanism was studied by transmission electron microscopy (TEM). The experimental results show that in the appropriate environment, MoS2 can be successfully grown on substrate with periodic holes, and the number of growth layers can be determined through measurements. By observing the growth mechanism, composition analysis, and selected area electron diffraction diagram by TEM, we comprehensively understand the growth phenomenon. The results of this research can serve as a reference for the large-scale periodic growth of MoS2. The production of periodic structures by laser drilling is advantageous, as it is relatively simpler than other methods.

Effect of Mold Width on the Flow Field in a Slab Continuous-Casting Mold with High-Temperature Velocity Measurement and Numerical Simulation

In this paper, the effects of the width of the mold on the surface velocity, flow field pattern, turbulent kinetic energy distribution, and surface-level fluctuation in the mold were studied with measurement of the flow velocity near the surface of the mold at high temperature with the rod deflection method and numerical calculation with the standard k-ε model coupled with the discrete-phase model (DPM) model for automobile exposed panel production. Under the conditions of low fixed steel throughput of 2.2 ton/min, a nozzle immersion depth of 140 mm, and an argon gas flow rate of 4 L/min, as the width of the mold increases from 880 mm to 1050 mm and 1300 mm, the flow velocity near the surface of the mold decreases. The flow direction changes from the positive velocity with the mold widths of 880 mm and 1050 mm to the unstable velocity with the mold width of 1300 mm. The calculated results are in good agreement with the measured results. The turbulent kinetic energy near the submerged entry nozzle (SEN) gradually increases, and the risk of slag entrainment increases. Under the conditions of high fixed steel throughput of 3.5 ton/min, the SEN immersion depth of 160 mm, and the argon gas flow rate of 10 L/min, as the width of the mold increases from 1600 mm to 1800 mm and 2000 mm, the velocity near the mold surface decreases. The flow velocity at 1/4 of the surface of the mold is positive with the mold width of 1600 mm, while the velocities are negative with the widths of 1800 mm and 2000 mm. The calculated results are basically consistent with the measured results. The high turbulent kinetic energy area near the nozzle expands to a narrow wall, and the risk of slag entrainment is significantly increased. In both cases of low and high fixed steel throughput, the change rules of the flow field in the mold with the width are basically the same. The argon gas flow rate and the immersion depth of SEN should be adjusted reasonably to optimize the flow field in the mold with different widths under the same fixed steel throughput in the practical production.

Study of ZrO2 coatings on 316L SS as a function of sputtering gas flow rate for biomedical applications

Coatings have attracted much attention because they improve the surface properties while retain favorable bulk properties. For the development of coatings in biomedical applications, the combination of the mechanical characteristics, tribological properties, corrosion behavior, and biocompatibility should be noticed. The present work addresses the mechanical and tribological characteristics and corrosion resistance of ZrO 2 coatings on 316L SS as a function of sputtering gas flow rate for biomedical applications. DC reactive magnetron sputtering technique was employed to deposit the coatings at different argon gas flow rates (5–20 sccm). X-ray diffraction method (XRD) and atomic force microscopy (AFM) were used to characterize the crystallographic structure and surface morphology . Mechanical and tribological properties of the coatings were evaluated by nanoindentation and scratch tests. The electrochemical behavior of the samples was also studied in Hank's solution at a physiological temperature (37 °C). The growth mechanism of the coatings was analyzed and subsequently, its effect on structure, morphology, and different properties was investigated. The results showed that the coatings deposited at lower sputtering gas flow rates (≤10 sccm) are more resistant to plastic deformation, wear, and corrosion in Hank's solution than those deposited at higher rates (>10 sccm) due to their dense structure as well as smooth and crack-free surface. • ZrO 2 coatings were used to improve the properties of 316L SS. • The coatings were deposited by DC reactive magnetron sputtering technique. • The growth mechanism of the coatings was analyzed as a function of sputtering gas. • The coatings deposited at lower flows were more resistant to plastic deformation. • The coatings deposited at lower flows were more resistant to wear and corrosion.

Highly efficient as-synthesized and oxidized multi-walled carbon nanotubes for copper(II) and zinc(II) ion adsorption in a batch and fixed-bed process

In this work, the optimization of temperature, argon gas flow rate, acetylene gas flow rate and time effect on the yield of as-synthesized multi-wall carbon nanotubes (AS-MWCNTs) using a novel iron-nickel/biochar catalyst was investigated. Subsequently, the AS-MWCNTs were functionalized to obtain oxidized multi-wall carbon nanotubes (OX-MWCNTs). The nanoadsorbents were applied for Cu(II) and Zn(II) ions adsorption from wastewater in a batch and fixed-bed process. Remarkably, the results revealed optimum AS-MWCNTs yield (280%) at the following experimental conditions; temperature (725 °C), argon gas flow rate (250 mL/min), acetylene gas flow rate (180 mL/min) and time (75 min). OX-MWCNTs demonstrated higher surface area of 1210 m 2/g compared to AS-MWCNTs (1140 m 2/g). The optimum removal of Cu(II) and Zn(II) ions were obtained at pH (6), contact time (30 min), adsorbent dosage (20 mg/L), initial metal concentration (Cu(II) (75 mg/L) and Zn(II) (80 mg/L)) and temperature (45 oC). Maximum adsorption capacities for Cu(II) and Zn(II) ions removal by AS-MWCNTs were obtained as 364.66 and 347.01 mg/g, while OX-MWCNTs produced higher maximum adsorption capacities of 416.47 and 411.88 mg/g. The experimental data were better fitted by Langmuir isotherm and pseudo-second order kinetics, while thermodynamic investigation revealed a favorable and spontaneous chemisorption controlled adsorption of metal ions. Furthermore, the breakthrough curves of Cu(II) and Zn(II) ions was suitably modelled by Thomas kinetic model. Accordingly, AS-MWCNTs and OX-MWCNTs indicate a promising choice to eliminate Cu(II) and Zn(II) ions in wastewater due to its stability, high efficiency, environmental friendliness and excellent recyclability capacity.

Analysis of Discharge Characteristics of Cold Atmospheric Pressure Plasma Jet

In this article, the investigation has been carried out for the characterization of the proposed tapered geometry of dielectric barrier discharge (DBD)-based cold atmospheric pressure plasma jet (C-APPJ) on the basis of optical emission spectroscopy (OES) and imaging for different operating parameters, such as argon gas flow rates, applied voltages, and frequencies. The detailed characteristics for the formation of the plasma plume using argon as a working gas have been presented for a wide range of flow rates [1–3 standard liter per minute (SLM)] and frequencies (15–25 kHz). Increasing the pulse frequency, the length and the diameter of the plasma plume increase, while the length of the plasma plume increases when increasing the gas flow rate up to 2 SLM. Time-integrated images have been captured using the intensified charge couple device (ICCD) camera, which illustrates that the plasma plume comprises different emission layers of definite patterns. The propagation dynamics and formation of different emission layers of the plasma plume have also been investigated using the COMSOL Multiphysics simulation. It has been observed that the local electric field of 6 kV/cm is responsible for the propagation of the plasma bullet and the generation of the electron with an average energy of ~9 eV. OES has also been performed to understand the plasma chemistry and identify the reactive species in the C-APPJ. The discharge analysis and characteristics performed through experiment and simulation would certainly be helpful for the design and development of C-APPJ sources.

Impact of Ar:O2 gas flow ratios on microstructure and optical characteristics of CeO2-doped ZnO thin films by magnetron sputtering

In this study, a radio frequency magnetron sputtering technique was applied to deposit eminently oriented ZnO thin films on stainless steel (SS316L). The effect of different ratios (Ar:O2) of gas flow ((20:0), (15:5), (10:10), (5:15), (0:20)) on optical and structural properties of CeO2-doped ZnO thin films has been examined. The increase in grain size of thin films was observed with a partial increase in the Ar:O2 sputtering gas at substrate temperature of 673 K. The average surface roughness of the thin films has increased with sputtering gas. The photoluminescence peak exhibited a broad green-yellow band spiked at 467 nm for all the samples of CeO2-doped ZnO thin films and a wide band of visible light focused in the 500–600 nm range. Intensity reduction of deep level emission peaks of ZnO films was observed. The refractive index of undoped and CeO2-doped ZnO thin films with various sputtering gas ratios (Ar:O2) were also investigated. The optimized argon gas flow rate findings allow us to choose the deposition conditions for CeO2-doped ZnO thin films for solar thermal applications.

Analysis of Current on Mechanical Properties and Microstructure of A53 Gr B Material with Gas Tungsten Arc Welding Process

The welding use correct process parameters will produce joint with optimum in mechanical properties. The current is a very important process parameter in welding. Gas Tungsten Arc Welding process carbon steel A53 Gr B uses current variations can be an option to get the best quality joints. The purpose of this research is to get optimum mechanical properties and microstructure by varying the current. The experimental method uses GTAW process by varying current in welding A 53 Gr B using a single V butt joint and a 5G welding position, the Argon protective gas flow rate of 15 liters per minute with filler rod ER 70 S-6. This process also uses 11-13 Volt voltage with DCEN polarity and current 70, 90, and 110A. Based on ASME Section IX, the test results show that the specimen with a current of 90A gives optimum results with a tensile strength of 480 MPa and a hardness value of 190 HV, whereas specimens with welding current of 70A bring incomplete penetration defects in the weld area. The use of welding current 90A in this research provides welding results with better mechanical properties and microstructure compared to the use of currents of 70 and 110A

The Characterization of hydrocarbon compounds in bio-oil produced by pyrolysis of biomass from the essential oil distilled residue using ZSM-5 and YSZ catalysts

The main hydrocarbon containing in petroleum and natural gas are important feedstocks for various kinds of fuel and petrochemical products, but these non-renewable resources will diminish their supply over time and that is why the development of environmentally friendly hydrocarbon resources whose more secure should be driven. One of the origins could become the residue of the distillation process of essential oils using catalytic pyrolysis that would produce the hydrocarbon distribution products. The use of acid catalysts such as ZSM-5 can improve the hydrocarbon in bio-oil. However, the use of zeolites can mainly accelerate the cracking of long molecules to make hydrocarbon molecules simpler by forming carbonium ions from the carbon-carbon chain. Thus, requiring a modification of the catalyst with adds YSZ catalyst, which can cut off oxygen from the hydrocarbon group is needed to improve the results of catalytic pyrolysis. The results of this study showed that the maximum temperature at 550 °C was able to increase the yield of steam products and the production of non-oxygenated hydrocarbon compounds. Similarly, the optimization condition of the argon gas flow rate is 100 mL/min. In that condition, the fluidization of biomass material occurs maximally, and the occurrence of the heat transfer process is very fast. While the optimum ratio of YSZ/ZSM-5 catalyst was achieved by a 3:2 ratio. YSZ is very effective at 550 °C in assisting ZSM-5 to form non-oxygenated hydrocarbon compounds. It can be proofed by GC-MS results that non-oxygenated compounds produced such a group of non-oxygenated hydrocarbon cyclic, paraffin, and aromatic compounds are dominant.

Preparation and performance of an Al/TiB2 + 10%Ti4O7/β-PbO2 as a composite anodic material for electrowinning of non-ferrous metals

Electrodes are the key material in the electrolysis of non-ferrous metals, and their selection and preparation can be a difficult problem in the hydrometallurgical industry. In this paper, starting from the selection of electrode materials and structural design, an Al/TiB2 + 10%Ti4O7-coating composite material was prepared by plasma spraying technology, and a β-PbO2 coating was prepared by electrochemical deposition. The phase composition of the coating was analyzed by X-ray diffractometer, and the structure of the coating was observed by scanning electron microscopy. Results show that the electrode prepared by electrodeposition at a current density of 0.03 A cm−2 has a more compact structure and more uniform grain size. Through steady-state polarization curve, cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy, the electrochemical performance of the electrode was studied. Through porosity measurements, it was found that the composite electrode material prepared by the plasma spraying method under the parameters of a spraying power of 36 kW, powder feeding rate of 30 g/min, spraying distance of 105 mm, and argon gas flow rate of 2.6 m3/h greatly reduces the charge resistance in the double-layer structure on the electrode surface, thereby accelerating the charge transfer rate. Plasma spraying and electrochemical deposition have been used to successfully prepare Al/TiB2 + 10%Ti4O7/β-PbO2 composite electrode materials with good corrosion resistance and electrochemical catalytic activity. Compared to Ti/β-PbO2 and Pb-(0.5 wt%)Ag/β-PbO2, the corrosion resistance and polarization potential increased by 83.6% and 93.0% and negatively shifted by 517.37 mV and 587.12 mV, respectively, and the catalytic activity was also significantly improved.

Analysis of Tungsten-Alumina Nanocomposite Thin Films on SS304 Substrate

Higher solar absorptance and lower thermal emittance are the key factors for solar collectors. The use of thin films that are having mechanically resistant coatings are common practice in industries. The primary motivation of carrying this research work is to lower thermal emittance and maximize solar absorptance on SS304 substrate material. W-Al2O3 composite coatings are developed using magnetron sputtering process by considering the process parameters. The experimental plan is achieved based on Taguchi L9 orthogonal under various levels for deposition parameters. The tungsten and alumina thin films deposited using a co-sputtering were characterized using 410 - solar instrument for measuring solar absorptance and ET 100 Emissometer for measuring thermal emittance. The optimization for process parameters on thermal emittance and absorptance were carried out. It was found that for deposition parameters of DC power 750W, RF power 1050W and Argon gas flow rate of 250 sccm, absorptance of 0.758 with thermal emittance of 0.061 is observed with deposition was carried out on SS304 substrates.

An accurate analytical method for the determination of antimony in tea and tap water samples: photochemical vapor generation-atom trapping prior to FAAS measurement

A sensitive and accurate sonication-assisted gas liquid separator-photochemical vapor generation-T-shaped slotted quartz tube with seven exit holes-atom trapping-flame atomic absorption spectrophotometry (SA-GLS-PVG-T-SQT-AT-FAAS) system was developed for the quantification of antimony at trace levels in daphne tea and tap water samples. A comprehensive univariate optimization was utilized to evaluate experimental conditions in terms of flame type, hydrogen gas flow rate, argon gas flow rate, trapping period, type of T-SQT and height of T-SQT. Under the conditions optimized, limit of detection (LOD) and limit of quantification values for the proposed method were figured out as 28.4 and 94.5 µg/L, respectively. Increment in detection power was recorded as 96-folds when LOD values of the FAAS, and the SA-GLS-PVG-T-SQT-AT-FAAS systems were compared to each other. Spiking experiments were also carried out for the evaluation of the method’s applicability and accuracy. Percent recovery results for both samples were found in the range of 90.2–108.0% using the SA-GLS-PVG-T-SQT-AT-FAAS system.

Studying of Plasma- Polymerized Pyrrole at Variable Gas Flow Rates Via Plasma Jet

In this manuscript has investigated the synthesis of plasma-polymerized pyrrole (C4H5N) nano-particles prepared by the proposed atmospheric pressure nonequilibrium plasma jet through the parametric studies, particularly gas flow rate (0.5, 1 and 1.5 L/min). The plasma jet which used operates with alternating voltage 7.5kv and frequency 28kHz. The plasma-flow characteristics were investigated based on optical emission spectroscopy (OES). UV-Vis spectroscopy was used to characterize the oxidization state for polypyrrole. The major absorption appears around 464.1, 449.7 and 435.3 nm at the three flow rate of argon gas. The chemical composition and structural properties of the contained samples which synthesized at 0.5 L/min as a argon flow rate were analyzed by scanning electron microscopy (SEM), Fourier transformation infrared spectroscopy (FTIR), Raman spectroscopy and X-ray diffraction (XRD). SEM point to a uniform distribution of polypyrrole (PPY) nanoparticles matrix. XRD technique showed a semicrystalline pattern for PPY)thin film. It is expected, that the high-quality plasma polymer grown by atmospheric pressure plasma jet method contributes to serving as conducting materials.

Flow Field in Slab Continuous Casting Mold with Large Width Optimized with High Temperature Quantitative Measurement and Numerical Calculation

In this paper, the rod deflection method was applied to quantitatively measure velocity near the mold surface at high temperatures and the k-ε model coupled with a discrete phase model (DPM) was adopted to simulate the flow field in the mold. The calculated results match very well with the measured results under all the present conditions. Under the conditions of the large mold width of 1800 mm, 1.1 m/min casting speed and 140 mm submerged entry nozzle (SEN) immersion depth, the velocity near the mold surface decreases with increasing the argon gas flow rate. When the argon gas flow rate is 6 L/min, the flow pattern is the double roll flow (DRF). When the argon gas flow rate is increased to 10 L/min and 14 L/min, the flow pattern is the single roll flow (SRF), and the risk of slag entrainment increases. With an argon gas flow rate of 10 L/min, and an immersion depth of 160 mm, the velocity near the mold surface sensitively increases with increasing the casting speed. When the casting speed is 1.1 m/min, an intermediate flow (IF) is formed with the intensified mold surface fluctuation, which can easily result in slag entrainment defects. When the casting speed is only increased to 1.2 m/min, the velocity near the mold surface changes drastically and is close to the upper limit velocity of 0.4 m/s. When the casting speed is 1.1 m/min, and the argon gas flow rate is 10 L/min, the velocity near the mold surface is obviously increased with increasing the immersion depth. When the immersion depth of the nozzle increases from 140 mm and 160 mm to 180 mm, the flow pattern changes from SRF or IF to DRF. When the bottom shape of the SEN changes from mountain to well, the velocity near the mold surface decreases. We suggest adopting the well-bottom nozzle to reduce the risk of slag entrainment.

Comprehensive assessment of hydrogen production in argon‐water vapors plasmolysis

AbstractA simultaneous investigation of simulation and experimental analysis of hydrogen production from argon‐water vapor mixture as a function in DBD plasma applied voltage were studied. The H2 concentration results of two Ar‐H2O simulation kinetics models were compared with the experimental results. The simulation analysis was implemented for Ar‐H2O models with and without the dissociative attachment reaction (H−). The effects of argon flow rate, input water vapor temperature, and water vapor flow rate on the H2 concentration from the Ar‐H2O mixture were investigated. Furthermore, the effect of argon addition and reactor temperature on the hydrogen production from water vapor plasmolysis was performed. It was found that the hydrogen concentration was enhanced with the argon gas flow rate and plasma voltage increase. Moreover, the H2 concentration results of the water vapor simulation model selecting the dissociative attachment reaction (H−) were nearly the same as that obtained from the experimental results. Also, it was observed that the energy efficiency was enhanced with the plasma input power increased. Moreover, the comparison showed that the hydrogen concentration of argon gas addition was lower than that obtained from water vapor plasmolysis at PTR heating temperature of 90°C.

Simple annealing process for producing unique one-dimensional fullerene crystal named fullerene finned-micropillar

We propose a process for easily fabricating a unique one-dimensional fullerene crystal, i.e., a fullerene finned-micropillar (FFMP). To fabricate a one-dimensional fullerene crystal more easily than when using current processes, fullerene was first annealed at 1173 K for 1 h with an argon gas flow of 0.5 L/min. We then examined how the FFMP structure changed when the fabrication process conditions, such as temperature, annealing time, and argon gas flow rate, were varied. FFMPs can be prepared within a short time and may have the same electrical characteristics as other one-dimensional crystals, e.g., fullerene nanowhiskers, so they are expected to be very useful for field-effect transistors, organic photovoltaics, and so on in the near future.