Hydrogen Gas Addition Research Articles

High Speed Ashing of Ion Implanted Photoresist by Microwave Excited Water Vapor Plasma with Powered Substrate

This study examined a substrate bias voltage introduced into a microwave excited water vapor plasma to enable fast ashing of photoresist implanted with high-dose ions without occurring popping. The ashing rate at the center of the ashing distribution for the photoresist implanted with boron with an implantation dose of 1×1016 atoms/cm2 was estimated as 1.0 μm/min. Results of plasma emission diagnostics suggest that rf bias application effects generated a plasma rich in excited hydrogen and oxygen atom near the substrate surface. This plasma is presumed to assist the removal of the hardened layer of ion implanted photoresist and to affect hydrogen gas addition. A self-bias voltage during bias application was sufficiently low, approximately －30 V, at a peak-to-peak voltage of 1 kV at 1 MHz.

Effect of oxy hydrogen gas addition on combustion, performance, and emissions of premixed charge compression ignition engine

Premixed Charge Compression Ignition (PCCI) is one of the well-known ways to achieve low NOx and Soot emissions in Internal Combustion engines. However, this strategy has shown limited scope to bring down the Carbon Monoxide (CO) and Hydrocarbons (HC) emissions. To overcome this drawback, a novel attempt had been made to use oxy hydrogen gas as fuel additive in the PCCI engine. The conventional CI engine was converted into PCCI engine by Port Fuel Injection of diesel fuel and preheating of air. The comparison was made between Conventional Diesel Combustion (CDC) and PCCI mode with and without use of oxy hydrogen gas. Due to accelerated chemical reactions, Indicated Mean Effective Pressure and Indicated Thermal Efficiency improved. Due to the addition of the oxy hydrogen gas the average reduction in CO emission was 26.19% at 25% load and 18.88% at 50% load. In the case of HC, the average emission reduction was 19.27% at 25% load and 23.74% at 50% load. NOx emissions were within the range of 10 ppm even after the addition of oxy hydrogen gas. The oxy hydrogen gas addition resulted in almost negligible Smoke and oxides of nitrogen emissions even without the use of exhaust gas recirculation.

Optimization of Sludge Fermentation for Volatile Fatty Acids Production

AbstractPrefermentation of primary solids can produce volatile fatty acids (VFAs), and operational strategies may affect the propionic acid content. In this study, three prefermenter phases were used to optimize VFAs using three separate strategies. The phases were (i) glycerol (biodiesel by-product) co-fermentation with primary solids, (ii) the effect of mixing energy on the co-fermentation of glycerol and primary solids and (iii) the effect of hydrogen gas addition on the co-fermentation of glycerol and primary solids. The Phase 1 data showed that glycerol increased the VFAs production 1.2× over the possible value from the added glycerol alone (427 mg-COD/l), implying that the glycerol addition stimulated additional fermentation of primary solids. In Phase 2, low mixing energy in glycerol increased the VFAs production by 80% while slightly favoring propionic acid over acetic acid compared to the higher mixing energy. The addition of hydrogen gas in Phase 3 did not increase the VFAs total production but significantly increased the concentration of propionic acid by 41%. All three optimization approaches performed well and were able to increase the VFAs production and/or increase propionic acid concentration relative to acetic acid.

Effect of hydroxy and hydrogen gas addition on diesel engine fuelled with microalgae biodiesel

Owing to high growth rate, being non-edible, and environmental friendliness; microalgae is a promising third generation biodiesel raw material. In this study, hydrogen and hydroxy gas aspirated compression ignition engine which was fuelled with microalgae biodiesel and low sulphur diesel fuel blend were investigated in order to evaluate their combined effect. The results showed that the brake power and torque output of the test engine decreased with microalgae biodiesel usage. Moreover, microalgae biodiesel addition results in lower carbon monoxide and nitrogen oxides emissions, and higher carbon dioxide. The introduction of hydrogen and hydroxy gas compensated the decrement of torque and power output and increment of carbon dioxide emission. The study enlightened that usage of microalgae biodiesel with hydrogen and hydroxy gas addition is a very promising combination from the environmental viewpoint.

Effect of hydrogen gas addition on combustion characteristics of pulverized coal

A promising approach to decrease CO2 emissions from blast furnaces during ironmaking is to blow a reducing gas containing hydrogen into blast furnaces from their tuyeres. However, the combustion behavior of pulverized coal in the presence of a hydrogen-containing gas has not been elucidated. In this work, the combustion experiments of pulverized coal using a drop tube furnace were carried out to investigate the effect of H2 gas addition on the combustibility of pulverized coal. The combustion ratio of char particles in the presence of H2 gas (when introduced at a flow rate of 0.10L/min) was larger than that in the absence of H2 gas. This is because of the enhanced release of volatile matter from coal and the combustion of char due to an increase in the temperature of the coal particles, which was caused by the drastic combustion of H2 gas. The combustion ratio of char particles when H2 gas was added at flow rates higher than 0.21L/min was considerably smaller than that obtained when H2 gas was not added. It was found that the combustibility of coal was enhanced when an optimum H2 gas flow rate was used.

Effects of ammonia borane on the combustion of an ethanol droplet at atmospheric pressure

Adding compounds rich in hydrogen to liquid fuels has the potential to change combustion behavior and enhance performance. One potential additive is ammonia borane (AB), which contains 19.6wt.% hydrogen and can be dissolved in anhydrous ethanol (up to 6.5wt.%). The particular system studied here would have limited use due to energy density and stability but is studied as a model system. Single droplet combustion experiments were performed with AB concentrations in ethanol varying from 0 to 6wt.%. Measurements performed using high speed (5kHz) planar laser-induced fluorescence (PLIF) indicate that hydrogen gas addition from the decomposition of AB continues throughout the droplet burning process. The hydrogen addition leads to an increase in the D2 law rate constant, k0, of up to 16%. While AB (and residual material) participates throughout the combustion process, it dramatically impacts the combustion behavior at the end of the droplet lifetime as the concentration of AB residual grows within the droplet. This results in droplet shattering, causing fine atomization and rapid combustion of the remaining fuel. Boron is also oxidized in this short period of time, increasing the energy released. In combustors, droplet shattering could enhance mixing and increase combustion efficiency. Thus, the approach of adding compounds rich in hydrogen is a promising method to introduce H2 gas to practical combustion systems, while enhancing performance.

Low temperature synthesis of ITO thin film on polymer in Ar/H 2 plasma by pulsed DC magnetron sputtering

Indium tin oxide (ITO) films were synthesized on polymer (PES, polyethersulfone) at low temperature less than 100 °C by pulsed DC magnetron sputtering. The microstructure evolution of ITO thin film was investigated by employing the hydrogen gas in Ar discharge. The discharge behavior with hydrogen gas addition was analyzed by optical emission spectroscopy (OES) and microstructure change was investigated by XRD and TEM. It could be confirmed that the discharge with a mixture gas of hydrogen and Ar made an effect on the ionization of indium and oxygen gases as measured by OES and also significantly promoted the formation of crystallites of ITO in amorphous matrix. As a result, the resistivity of ITO film was significantly improved to 5.27 × 10 − 4 Ω·cm at 0.026 Pa of hydrogen partial pressure below 100 °C in comparison with 2.65 × 10 − 3 Ω·cm under hydrogen free condition.

Effects of bromoethansulphonic acid and monensin on in vitro fermentation pattern of non-fasted rabbits

Effects of bromoethansulfonic acid (2-BES) and monensin (M) on caecal fermentation pattern of fasted (F) and non-fasted (NF) rabbits (14 in total), were studied using in vitro batch incubations. In the first experiment, caecal contents were collected from 4 F (24 h) and 4 NF conventional rabbits (70–77 days old). They were incubated for 24 h at 39°C under 100% CO 2 or 50% CO 2 +50% H 2 atmosphere with 2-BES (1–20 mM) and monensin (50 mg/kg) and net production of volatile fatty acids (VFA) and methane (CH 4) was measured and hydrogen recoveries (2Hr) calculated. In fasted rabbits, 2-BES addition (1 mM) caused a slight decrease in CH 4 (14%) without changing the fermentation pattern whereas M caused a decrease in CH 4 (51%) accompanied by a decrease in total VFA production (29%), mainly butyrate (B) (37%) and acetate (A) (33%). In NF rabbits, 2-BES (20 mM) depressed CH 4 (93%) while M induced a surprising increase in CH 4(56%) coupled to a decrease in total VFA (16%), mainly B (34%). The consequent increase (31%) in the calculated hydrogen recoveries (2Hr) was hypothesized to be due to a decrease in acetogenic and reductive acetogenic bacteria. In the second experiment, hydrogen gas addition to caecal contents from 3 NF rabbits increased total VFA production (12%), mainly butyrate (32%) and monensin induced an increase in CH 4 production (33%) and changed the fermentation pattern towards lower total VFA, lower B and higher P. As microbial counts did not reveal a decrease in acetogenic and reductive acetogenic bacteria when monensin was added, it was hypothesized that the increase in CH 4 was due to a depression of their autotrophic activity, leaving more H 2 available for methanogenesis and reductive acetogens survived than heterotrophically.

The effect of hydrogen addition to some HCN laser active mixtures on the C.W. output power at 337 μm

An experimental investigation has been carried out in order to find out the effect of hydrogen gas addition to the basic HCN laser fuel on the continuous output power of the laser at 337 μm. The experiment has been performed by adding hydrogen to the striated discharge at a constant flow rate, pressure and external glass tube temperature, and for stabilized currents ranging from 0.2 to 0.9 A. With the exception of the ethylene-nitrogen mixture, the output power of the laser decreased for hydrogen enriched mixtures regardless of the magnitude of the hydrogen percentage added to the basic constituents. However, the alteration of the chemical composition of the gaseous mixture led to the variable mode supression at 337 μm for the fundamental transverse and the next higher mode.