Electrode Barrier Research Articles

Investigation on the Regulation of the Combustion Characteristics of a Propane/Air Mixture by Repetitive nSDBD Pretreatment.

This paper investigates the effect of the transient repetitive nanosecond surface dielectric barrier discharge (nSDBD) pretreatment on the combustion characteristics of combustible mixtures. A method of using nSDBD online pretreatment of a combustible mixture to regulate the combustion characteristics of the mixture is proposed. The study is conducted in a constant-volume combustion chamber at atmospheric pressure and temperature using a propane/air mixture as fuel. The discharge characteristics of repetitive nSDBD and the effects of pretreatment discharge energy and interval time between the pretreatment and ignition on combustion rate are discussed. The results show that (1) For 12.5 kHz pulses, the filament length generated with the annular dielectric barrier electrode discharge can reach up to 7 mm, and the number of discharge filaments per pulse can reach 40. (2) Pretreating mixtures using repetitive nSDBD at millisecond time scale can significantly improve the combustion process. (3) Repetitive nSDBD pretreatment can enhance the activity of the mixture near the surface of nSDBD electrode, which leads to obvious wrinkles on the flame surface and significantly improves the combustion rate. (4) The flame rise time decreases with the increase of discharge energy and increases with the increase of the interval time between the pretreatment and ignition. The effect of the repetitive nSDBD pretreatment on flame propagation during the flame development period becomes more pronounced with the increase of the excess air coefficient. The research results of the paper reveal the law of online regulation of combustion characteristics of combustible mixtures by the nSDBD, providing experimental data support for the mechanism research of online regulation of combustion characteristics of combustible mixtures by the nSDBD.

Microdischarge dynamics of volume DBD under the natural convection airflow

The dielectric barrier discharge (DBD) at ambient air conditions exhibits discrete structure and contains thin microdischarge plasma filaments. Understanding the formation, self-interaction, and dynamics of such filaments is crucial towards the generation of uniform diffuse-like DBD in air, and also for the study of the memory effects and self-organized complex patterns. In this paper, the impact of natural convective flow, driven by the temperature gradient between self-heated discharge cell electrodes and ambient air, on the collective dynamics of microdischarges was studied in parallel-plate volume dielectric barrier discharge for the different geometrical arrangements. The horizontal arrangement corresponds to the parallel direction of discharge propagation and convective flow, while in the vertical arrangement buoyancy flow transverse to the discharge propagation column. For the horizontal arrangement, the randomly directed motion of microdischarges was observed. While at the vertical arrangement of the discharge cell, the buoyancy flow initiates the directed motion of the microdischarges following the gas flow. The continuous self-heating of the barrier electrodes during the DBD operation leads to a larger thermal gradient and increasing in the microdischarge channels. The larger thermal gradient results in a more pronounced directed motion of microdischarges with a higher velocity. The velocity of convective flow in the discharge gap was estimated by the simulation and compared with the mean velocity of MD channels obtained by the particle image velocimetry method.

Intrinsic supercurrent non-reciprocity coupled to the crystal structure of a van der Waals Josephson barrier

Non-reciprocal electronic transport in a spatially homogeneous system arises from the simultaneous breaking of inversion and time-reversal symmetries. Superconducting and Josephson diodes, a key ingredient for future non-dissipative quantum devices, have recently been realized. Only a few examples of a vertical superconducting diode effect have been reported and its mechanism, especially whether intrinsic or extrinsic, remains elusive. Here we demonstrate a substantial supercurrent non-reciprocity in a van der Waals vertical Josephson junction formed with a Td-WTe2 barrier and NbSe2 electrodes that clearly reflects the intrinsic crystal structure of Td-WTe2. The Josephson diode efficiency increases with the Td-WTe2 thickness up to critical thickness, and all junctions, irrespective of the barrier thickness, reveal magneto-chiral characteristics with respect to a mirror plane of Td-WTe2. Our results, together with the twist-angle-tuned magneto-chirality of a Td-WTe2 double-barrier junction, show that two-dimensional materials promise vertical Josephson diodes with high efficiency and tunability.

Unveiling atomic structure and chemical composition of the Al/AlOx/Al Josephson junctions in qubits

Qubits incorporating Josephson Junctions are essential for developing quantum computing devices, nevertheless, nanostructure and chemical information of the junction have yet been distinctly understood. To address it, comprehensive investigation is performed to decipher atomic structure and compositional features of the Josephson junction which basically consists of an Al/AlOx/Al tri-layer materials system. It is revealed that the top-Al and the bottom-Al layers are with the thickness of 25.8 ± 0.8 nm and 20.4 ± 1.4 nm, respectively, slightly smaller than the intended thickness of 30 nm, which may be due to the inherent error associated to the measuring method based on cross sectional transmission electron microscopy micrographs. In addition, both the top and bottom crystalline Al layers comprise columnar grains with the size of approximately 20 × 30 nm. The AlOx tunnel layer is roughly 2∼4 nm thick and is composed of amorphous materials. The interfaces between AlOx and Al electrodes are jagged rather than flat, implying thickness inhomogeneity which can be possibly ascribed to the mechanisms of atomic steps and grain boundary grooving. Moreover, EELS spectrum imaging reveals a 0.5 nm-thick interfacial layer at boundary of AlOx barrier and Al electrodes. Unique ELNES features at the interfacial layer, including a −2 eV onset-shift of the O-K edge, are correlated with reduction of electronic properties of the barrier layer. Atom probe tomography reveals that composition of the bottom-Al/Si substrate interface primarily comprises AlO, O, C, Al2O, SiO, SiO2, P, O2 and Al2O2 and small quantities of SiC2, B and AlO2. Furthermore, significant strain, e.g., ∼3% normal and shear strain, can be detected in the bottom-Al layer grains, which probably stems from the uneven Si surface during the qubit fabrication process.

Colossal permittivity of (Tm+Nb) co-doped rutile-TiO2 ceramics with ultralow dielectric loss and excellent thermal stability

(Tm0.5Nb0.5)xTi1−xO2 (x = 0, 0.01, 0.02, 0.04 and 0.06) (TNTO) ceramics were prepared by solid-state reaction method. The effect of (Tm+Nb) co-doping concentration on the phase, microstructure and dielectric properties of the fabricated ceramics were investigated. A ultralow dielectric loss (0.006, at 1 kHz) and colossal permittivity (CP) (2.17 ×104, at 1 kHz) were obtained in the prepared TNTO ceramics (x = 0.01). The dielectric properties of the (Tm0.5Nb0.5)0.01Ti0.99O2 ceramics show excellent temperature- and frequency-stability in the range of − 150–260 °C (Δε′ (T)/ε′30< ± 15%, at 1 kHz) and 20–106 Hz. It was found that, the dielectric properties of (Tm+Nb) co-doped TiO2 ceramics have three significant temperature-dependent relaxations caused by electron-pinned defect-dipoles (EPDD) effect, internal barrier layer capacitance (IBLC) effect and electrode effect, respectively. The reported (Tm+Nb) co-doped TiO2 ceramics with ultralow dielectric loss and excellent thermal stability could be considered as one of the most promising candidates for applications in microelectronics.

Correlation between resistive switching characteristics and density of traps observed in Zr3N2 resistive switching memory devices with TiN barrier electrode

In this study, we present a correlation between the resistive switching (RS) characteristics and the traps of Zr3N2, which is based resistive random-access memory (RRAM) with a TiN barrier electrode, in order to identify the RS mechanism of the trap-based RRAM devices. First, gradual asymmetrical RS properties were discovered in the RS test, which included a current ratio of >2.51 × 102 and a large read margin of 480. As a result of analyzing the trap, the RS characteristics were deeply related to the nitride trap density (Nnt) in the Zr3N2 films as opposed to the interface trap density (Nit) at Zr3N2/p-Si layer. In addition, in the trap evaluation for four different resistance states, we observed that the Nnt was consistently increased with a decreasing resistance. These results indicate that the resistance state of the proposed TiN/Zr3N2/p-Si memory cell is determined by the Nnt, which means that controlling the Nnt is important in order to achieve a stable resistance state.

Giant dielectric response and relaxation behavior in (Tm + Ta) co-doped TiO2 ceramics.

Dielectric materials with huge dielectric constants are attracting attention due to the growing demand for microelectronics and high energy-storage devices. In this work, Tm + Ta co-doped TiO2 ceramics were prepared by a solid-state reaction (SSR) method, and the microstructure and dielectric behavior were investigated. A ultrahigh permittivity (εr ∼ 2.26 × 104) and very low loss (tan δ ∼ 0.011) are achieved at 1 kHz for (Tm0.5Ta0.5)0.01Ti0.99O2 ceramics. XPS analysis confirms that the high dielectric constant and low dielectric loss are attributed to the electron pinned defect dipole (EPDD) response formed by the coupling of Ti3+ and oxygen vacancies. In addition, impedance analysis and frequency dependent dielectric constant under a DC bias indicate that the presence of the internal barrier layer capacitance (IBLC) response and electrode response at low to medium frequencies (<106 Hz) also contribute significantly to the dielectric constant. The findings reported in this work provide valuable insights into the simultaneous realization of a low dielectric loss and high permittivity in Tm + Ta co-doped TiO2 ceramics and other related dielectric ceramics.

Thermal stability and interfacial structure evolution of Bi2Te3-based micro thermoelectric devices

Bi2Te3 based thermoelectric device is the only commercialized thermoelectric module. The thermal stability of the interface between the thermoelectric materials and barrier layer or electrode plays pivotal role for the stability and reliability of micro thermoelectric devices especially for power generation. In this work, the thermal stability, bonding strength and structure evolution of the interface between Bi2Te3 based materials (both n type and p type materials) and Ni barrier layer were systematically investigated. The interface between Ni and Bi2Te3 based materials demonstrates an ohmic contact with the contact resistivity of 3.64 μΩ cm2 and 5.31 μΩ cm2 for p-type and n-type element respectively. The bonding strength of p-type and n-type element with electrode is 13.43 MPa and 17.62 MPa, respectively. Upon annealing at 423 K for 7 days, due to the mass diffusion between Ni and Bi2Te3 based materials, a thin Ni-Te layer is formed. With further extending the annealing time at 423 K to 42 days, the thickness of the diffusion layer increases to 3 µm. The growth of diffusion layer enhances the bonding strength to 19.81 MPa. However, this is accompanied with a sharp increase in the contact resistivity to 14.48 μΩ cm2 for n-type element and to 6 μΩ cm2 for p-type element with Ni barrier. The increase in the contact resistance deteriorates the output power of thermoelectric module especially for the micro-device from 2.60 mW to 2.48 mW under the temperature gradient of 20 K. This work points out that for the application of Bi2Te3 based thermoelectric device in power generation above 423 K, appropriate barrier layer is indispensable and plays significant role for the performance of the device.

Simulations of High Non-Uniform Electric Field in Dielectric Barrier Electrode System

An electric field in the dielectric barrier electrode system is necessary for ozone production because ozone is produced by the electric discharge of O2 under a high-intensity electric field. The gas discharge plasmas contain energetic particles, such as electrons, ions, atoms, and radicals. The recombination of the O atom and O2 in the plasma will form O3. In this paper, the dependence of DC electric field formation on electrode geometry and the gap between electrodes and dielectric materials were examined by using computational modeling. Thus, a set of electrode geometry, gap distance, and dielectric material were obtained for high-intensity and uniform electric field generation. The COMSOL Multiphysics software was used for the modeling. Among the electrode geometries of plate-plate, pin-plate and mesh-plate, the mesh-plate generated high-intensity and uniform electric field. In the modeling, dielectric materials, including quartz, mica, alumina, and water, were compared. The highest intensity of electric field occurred on the water surface. HIGHLIGHTS When the gap distance between two parallel electrodes is less than 100 mm, the electric field in the gap is constant, independent of the space A high-intensity and uniform electric field is generated in the gap between the dielectric and grounded electrodes when a fine mesh high-voltage electrode is utilized With the fine mesh electrode, the electric field is about two times higher than the conventional plate electrodes, whereas the electric field uniformity was about 90 %. Therefore the barrier discharge will be initiated with lower high voltage GRAPHICAL ABSTRACT

Interfacial reactions in Zn4Sb3/titanium diffusion couples

Cheap, environmentally-friendly zinc antimonide is considered more favorable than conventional tellurite-based and skutterudite thermoelectric (TE) materials. Although the highly mobile zinc atoms located in the interstitial sites of the Zn4Sb3 crystalline structure greatly increase the figure of merit (ZT) of TE materials, the high chemical activity of zinc also makes it difficult to find suitable barrier layer and electrode materials. This paper introduces a method of joining titanium with Zn4Sb3 by means of diffusion bonding, in which the critical mutual-interdiffusion phenomenon is prevented. Optimal process parameters for manufacturing TE modules are suggested in this work. The intermetallic compounds (IMCs) that formed at the interface of Zn4Sb3/Ti diffusion couples were proved to be stable at the temperature with the highest conversion efficiency of Zn4Sb3. The growth kinetics of IMCs were also investigated, and the joint strength could be enhanced to 13.9 MPa after long-term reliability tests of 1000 h without deterioration. The results indicated that titanium is feasible barrier layer and electrode material for Zn4Sb3 TE modules.

Colossal permittivity of (Gd + Nb) co-doped TiO2 ceramics induced by interface effects and defect cluster

Material with high dielectric constant plays an important role in energy storage elements. (Gd + Nb) co-doped TiO2 (GNTO) ceramics with giant dielectric permittivity (>104), low dielectric loss, good temperature and frequency stability in broad range of 30–150 °C and 102–106 Hz have been systematically characterized. Especially, a low dielectric loss of 0.027 and a giant dielectric permittivity of 5.63 × 104 at 1 kHz are attained for the composition with x = 0.01. Results of complex impedance spectroscopy, I–V curve and frequency dependent dielectric constant under DC bias indicate that internal barrier layer capacitance (IBLC) effect, electrode effect and electron-pinned defect-dipole (EPDD) effect contribute to the colossal permittivity (CP) property simultaneously.

High energy efficient degradation of toluene using a novel double dielectric barrier discharge reactor

A double dielectric barrier discharge (DDBD) reactor was established to decompose toluene with high energy efficiency. Differences in discharge characteristics including visual images, voltage-current waveforms, Lissajous figures, and temperature variation, were determined between the DDBD and SDBD reactors. Removal efficiency, mineralization rate, CO2 selectivity, and energy yield were used to evaluate the toluene abatement performance of the two reactors. Compared to the SDBD reactor, the DDBD reactor exhibited more uniform and stable discharges due to a change in discharge mode. In addition, the DDBD reactor’s dissipated power and reactor temperature (including the gas, barrier and ground electrode) were significantly lower than those in the SDBD reactor. At 22−24 kV, the DDBD reactor showed a higher toluene removal efficiency and mineralization rate, while at 14−16 kV, the SDBD reactor exhibited higher respective value. The energy efficiency of the DDBD was 2.5–3 times that of the SDBD reactor, and the overall energy constant koverall of the DDBD reactor (1.47 mL/J) was significantly higher than that of the SDBD reactor (0.367 mL/J) as revealed by the kinetics study. Lastly, a plausible toluene degradation mechanism in the DDBD and SDBD reactors was proposed based on organic intermediates that formed during toluene decomposition.

Effect of Lattice Distortion on the Magnetic Tunnel Junctions Consisting of Periodic Grating Barrier and Half-Metallic Electrodes**Supported by the National Natural Science Foundation of China under Grant Nos. 11704197 and 61574079, and the NUPTSF under Grant No. NY217046.

A spintronic theory is developed to study the effect of lattice distortion on the magnetic tunnel junctions (MTJs) consisting of single-crystal barrier and half-metallic electrodes. In the theory, the lattice distortion is described by strain, defect concentration and recovery temperature. All three parameters will modify the periodic scattering potential, and further alter the tunneling magnetoresistance (TMR). The theoretical results show that: (1) the TMR oscillates with all the three parameters; (2) the strain can change the TMR about 30%; (3) the defect concentration will strongly modify the periodic scattering potential, and further change the TMR about 50%; and (4) the recovery temperature has little effect on the periodic scattering potential, and only can change the TMR about 10%. The present work may provide a theoretical foundation to the application of lattice distortion for MTJs consisting of single-crystal barrier and half-metallic electrodes.

Evolutionary dynamics of single-multiple columns in atmospheric helium dielectric barrier discharge

Dielectric barrier discharge is widely used as a low-temperature plasma source in industry. Columnar discharge is an important form of dielectric barrier discharge. However, its discharge theory has not been clear yet. In this paper, the dielectric barrier discharges in helium at atmospheric pressure are carried out between parallel dielectric barrier electrodes to study the evolutionary dynamics of single-multiple columns. By reducing the applied voltages to a value lower than the initial discharge voltage, the pattern of the columnar discharge evolves from a single column into multiple columns. Discharge images from the bottom are taken to observe the evolution of discharge and measure the diameter of discharge column and spacing between columns. The applied voltage, the Lissajous figure, the discharge current, and the discharge transferred charge are measured in order to calculate the Coulomb force and the magnetic field force exerted on the column by the other columns. It is found that in columnar discharge, there is a dynamic evolution process that the single columnar discharge evolves into the two-layered columnar discharge when the applied voltage slightly decreases instantaneously. On the one hand, the column diameter is different in different layer: the column diameter increases from the center to the outer layer. On the other hand, as the applied voltage decreases, the diameter of the center column grows and the spacing between the center column and its adjacent column decreases. The calculations show that the Coulomb force is far greater than the magnetic field force when the evolution is stable, which indicates that, as mentioned in the established knowledge, there is a confinement potential to balance the Coulomb force, thereby keeping the distribution of discharge columns stable. Furthermore, the results also show that the Coulomb force on the discharge columns at different voltage and position is different. The strength of Coulomb force on column is different at different layer: it decreases from the outermost layer to the center column, which is zero on the center column. Based on the balance between the Coulomb force and the confinement potential in columnar discharge, it is suggested that the strength of the latter may also follow the same law. In addition, as the applied voltage decreases, the charges accumulated on the surface of the dielectric and the number of discharge columns both increase, which results in the increase of the maximum of the Coulomb force. The confinement potential may increase as well and follow the same law.

Four distinct resistive states in van der Waals full magnetic 1T-VSe2/CrI3/1T-VSe2 tunnel junction

Two-dimensional (2D) intrinsic magnets have been successfully utilized to make the multifunctional van der Waals (vdW) spintronic devices. In this work, we design a vdW magnetic tunnel junction (vdW MTJ) formed by a ferromagnetic (FM) monolayer CrI3 barrier sandwiched between two 2D FM 1T-VSe2 electrodes and investigate the magnetic anisotropy and the tunneling magnetoresistance (TMR) effect of this vdW MTJ by using first-principles calculations. It is found that different from the conventional MTJs, four different magnetic configurations can be achieved in the vdW MTJ based on 1T-VSe2/CrI3/1T-VSe2 heterostructure when the magnetic moments of top electrode are pinned to be [0 0 1] axis. Moreover, the conductance of vdW MTJ based on 1T-VSe2/CrI3/1T-VSe2 heterostructure is the highest (lowest) when the magnetic moments of barrier and bottom electrode are all along [0 0 1] ([001¯]) axis, and a highest TMR ratio of 178% can be obtained in this vdW MTJ. The large changes of tunneling conductance with different magnetic configurations originate mainly from the large variation of the effective majority- and minority-spin transmission channels of FM 1T-VSe2 for different magnetic configurations. Our results suggest that vdW MTJ based on 1T-VSe2/CrI3/1T-VSe2 heterostructure holds great potential in multi-states magnetic storage for spintronics.

Inhibition of microbial growth by cold atmospheric plasma compared with the antiseptics chlorhexidine digluconate, octenidine dihydrochloride, and polyhexanide

The inhibition of microbial growth is the first step toward avoiding the formation of biofilms. Therefore, this study aimed to compare the microbiostatic activity of cold atmospheric pressure plasma (CAP) with three commonly used antiseptic agents to find an alternative to or supplementary concept for antiseptic treatment. The efficacy of two CAP generating devices − the plasma jet kINPen09® and a hollow dielectric barrier electrode (HDBD) − both working with argon with or without admixture of 1% oxygen, was compared with chlorhexidine digluconate (CHG 0.0001 and 0.00000625%), polyhexanide (PHMB 0.0001 and 0.000025%) and octenidine dihydrochloride (OCT 0.0002 and 0.00005%). The antiseptics were added to the planktonic stage of the biofilm‐forming strains Pseudomonas aeruginosa SG 81, Staphylococcus epidermidis RP 62A, Streptococcus mutans DSM 20523 and Candida albicans ATCC 10231 resp. SC 5314. The antiseptics were present during the subsequent cultivation period (32.5 h), whereas CAP was applied for only 60 s with the same cultivation period after the exposition. During the cultivation period, growth was measured every hour by optical density and analyzed with the calculated area under the curve (AUC) to determine the delay of exponential growth. Except for the higher resistance of C. albicans against PHMB and S. mutans against CHG, P. aeruginosa was the most resistant test organism against the other antiseptic treatments. OCT 0.0002% was the most effective among the tested antiseptic agents. The plasma jet did not differ from OCT in its efficacy against C. albicans and S. mutans. Against P. aeruginosa and both Candida strains, the plasma jet was more effective than against both Gram‐positive test strains. In terms of efficacy against Candida spp., the HDBD (dielectric barrier discharge plasma) did not differ significantly from the plasma jet with argon plasma; in contrast, the bacteriostatic efficacy was significantly higher. While the addition of 1% O2 did not change the efficacy of the plasma jet, the efficacy of the HDBD against S. epidermidis increased significantly. The antimicrobial efficacy of CAP as demonstrated in earlier studies was confirmed with planktonic microorganisms showing delayed growth during cultivation for 32.5 h after a single application of CAP for 60 s. Short treatment with CAP could be an effective alternative or supplement to conventional antiseptics, for example, to inhibit the growth of microorganisms in an infected wound. OCT in the concentration used here showed the best microbial growth inhibitory results among the antiseptics.

Understanding the characteristics of nano mineral oil under nonstandard oscillatory impulse voltage

This paper illustrates the breakdown strength of oscillatory impulse voltage for different barrier electrode gap with the dispersed titania (Tio2) nanoparticles in the mineral oil. The breakdown strength varies with addition of surfactant added in the nanoparticles and with different frequencies. Comparison is done by undergoing breakdown tests using alternating current (AC), direct current (DC), and lightning impulse voltages. Tests are to be done to prove that sin bidirectional oscillatory impulse voltage (SBOIV) provides higher breakdown strength when titania is dispersed in mineral oil and higher than other standard voltages.

Fast and flexible strategy to produce electrochemical paper-based analytical devices using a craft cutter printer to create wax barrier and screen-printed electrodes

This paper describes a simple, low-cost, and highly flexible rapid prototyping method to construct electrochemical paper-based analytical device (ePAD) for multiplexed analyte determinations. The ePAD was composed of two electrochemical cell (EC) compartments, separated by hydrophobic barriers of wax, and screen-printed electrodes (SPEs) deposited directly over the surface of the filter paper. The ePAD was entirely constructed using an inexpensive craft cutter printer with no needed of a wax printer. The rapid prototyping method involves two steps: the deposition of the SPEs and the creation of the wax barriers. In this case, the SPEs were screen-printed on filter paper by using adhesive tape as mask by cutting the electrodes pattern with the cutter printer. Following, the wax barriers were created using stamps made of filter paper also cut with the printer and impregnated with wax. In the ePAD, each ECs containing an array of 4-working electrodes, allowing up to 4 replicates in a single measurement. Both ECs shared one counter and one reference electrodes, permitting the simultaneous multianalysis. The ePAD was successfully applied to simultaneous detection of paracetamol (PAR), caffeine (CAF), and ascorbic acid (AA) in drugs. PAR and CAF were detected in a sample using one EC and AA was detected, in a different sample, on the other EC, both with no chemical modifications in the working electrodes. Limits of detection of 0.04 mmol L−1 for PAR, 0.22 mmol L−1 for CAF, and 0.40 mmol L−1 for AA were obtained. The construction process proposed provide an easy way to implement screen-printing electrodes and wax barriers in filter paper to create electrochemical devices for fast and simultaneous multianalysis.

Dielectric barrier discharge plasma application to convert used cooking oil into biodiesel

Plasma research on used oil (waste cooking oil) processing into biodiesel using Dielectric Barrier Discharge (DBD) has been conducted. Plasma technology can process used oil into biodiesel without using chemical catalysts. The DBD reactor in this research was formed by inside electrode, barrier and outside electrode components. The inside electrode is screw stainless steel with diameter 0,79 cm. The barrier is pyrex tube with thickness 0,25 cm. The outside electrode is copper wire which is wound into the pyrex tube. Plasma was flowed by argon gas with debit rate 2 L/minutes. In plasma reactor was connected AC voltage 1,6 kV. The oil mixed with methanol by volume ratio 6:1. Both materials were inserted into a reactor with the time variation of 30, 60, 90, 120, 150 min. The optimum result was obtained at 30 minutes treatment. The oil which was resulted has density 0.87 g/cm3, viscosity 4.1 mm2/s, acid number 0. 56 mg KOH/g, iodine number 31.64% -mass and 16.01% are mono-alkyl ester compound, and it was classified in National Indonesian Standard (NIS).

An Experimental Study of Plasma Cracking of Methane Using DBDs Aimed at Hydrogen Production

We report the results of an experimental campaign about the production of hydrogen from methane cracking using a non-thermal plasma. Experiments have been performed using a nanosecond pulse high-voltage generator in a cylindrical dielectric barrier electrode setup. Our experiments show that high methane conversion could be achieved by pulsed electrical discharges in DBD configuration. Conversion could be as high as 60%, with a hydrogen yield of about 25%. The energy costs lie in the range 30–40 eV for molecule. Another set of experiments using a traditional sinusoidal dielectric barrier discharge reactor suggests that argon dilution could improve the performances of plasma methane reforming. A similar suggestion could be inferred by analyzing the results of numerical simulations of the gas-phase chemical kinetics evolution under pulsed electrical discharge conditions.