Addition Of Hydrogen Gas Research Articles

Enhancing diesel engine performance and emission reduction through hydrogen enrichment in algal biodiesel blends.

The introduction of hydrogen into the engine could enhance its combustion efficiency and emission characteristics. The current study examines the attributes of compression ignition (CI) engines by introducing hydrogen into a biodiesel blend derived from algae. The improved thermal properties of hydrogen, when combined with algae biodiesel, significantly affect the performance, combustion, and emissions of dual-fuel engines. A study was conducted to evaluate the impact of hydrogen enrichment levels of 5%, 10%, 15%, and 20% of the nozzle volume on a biodiesel blend fuel. In comparison to diesel, algal biodiesel reduces emissions of unburned hydrocarbons (HC), carbon monoxide (CO), and oxygen (O2) by 5.19%, 3.61%, and 2.83%, respectively, while increasing nitrogen oxide (NO) emissions by 4.73%. In contrast to biodiesel, diesel demonstrated superior brake thermal efficiency (BTE) and lower specific energy consumption (SEC). Injecting hydrogen into A20 blend fuel at volumes of 5%, 10%, 15%, and 20% results in a respective increase in brake thermal efficiency of 2.65%, 2.97%, 3.50%, and 4.15%. The addition of hydrogen gas to biodiesel blends further enhances their combustion qualities, leading to elevated peak cylinder pressure, temperature, and heat release rate. The results indicate that A20H5, A20H10, A20H15, and A20H20 fuel reduced CO emissions by 3.75%, 8.75%, 12.5%, and 16.25%, respectively, compared to the A20 blend. In the same vein, HC emissions decreased by 5.76%, 10.29%, 15.52%, and 18.98%, respectively, as compared to A20 fuel. However, NO emissions rose by 5.36%, 10.20%, 15.28%, and 23.23%, respectively, for A20H5, A20H10, A20H15, and A20H20 test fuels. Ultimately, the utilization of algal biodiesel and hydrogen enrichment in diesel engines was proven to substantially reduce pollutants while increasing efficiency. This study contributes valuable insights into the intersection of renewable fuels, hydrogen enrichment, and engine technology, with the potential to drive significant advancements in sustainable transportation and environmental conservation.

Cross-Linked Polyolefins through Tandem ROMP/Hydrogenation.

Cross-linked polyolefins have important advantages over their thermoplastic analogues, particularly improved impact strength and abrasion resistance, as well as increased chemical and thermal stability; however, most strategies for their production involve postpolymerization cross-linking of polyolefin chains. Here, a tandem ring-opening metathesis polymerization (ROMP)/hydrogenation approach is presented. Cyclooctene (COE)-co-dicyclopentadiene (DCPD) networks are first synthesized using ROMP, after which the dispersed Ru metathesis catalyst is activated for hydrogenation through the addition of hydrogen gas. The reaction temperature for hydrogenation must be sufficiently high to allow mobility within the system, as dictated by thermal transitions (i.e., glass and melting transitions) of the polymeric matrix. COE-rich materials exhibit branched-polyethylene-like crystallinity (25% crystallinity) and melting points (Tm = 107 °C), as well as excellent ductility (>750% extension), while majority DCPD materials are glassy (Tg = 84 °C) and much stiffer (E = 710 MPa); all materials exhibit high tensile toughness. Importantly, hydrogenation of olefins in these cross-linked materials leads to notable improvements in oxidative stability, as saturated networks do not experience the same substantial degradation of mechanical performance as their unsaturated counterparts upon prolonged exposure to air.

Effect of CO2 and H2 gas mixture in cold water immersion on recovery after eccentric loading

BackgroundThe findings of previous studies support the efficacy of cold water immersion (CWI) with carbon dioxide (CO2) in enhancing muscle blood flow and maintaining aerobic performance efficiency. We hypothesize that the addition of hydrogen gas (H2), known for its antioxidant properties and role in inflammation regulation, to C-CWI can enhance recovery after eccentric exercise. Subjectsand Methods: Thirty-four healthy subjects performed a knee-extensor eccentric exercise. They were randomly allocated into four groups: control, CWI, CO2-rich CWI (C-CWI), and CO2 + H2 gas mixture CWI (CH-CWI). In the three CWI groups, all subjects were immersed in the appropriate bath at 20 °C for 20 min immediately after 60 repetitions of eccentric exercise. Before exercise and after 48 h of recovery, the subjects' maximal voluntary isometric contraction torque (MVC-ISO), maximal voluntary concentric (MVC-CON) contraction torque, countermovement jump (CMJ) height, knee flexion range of motion (ROM), muscle soreness, and muscle thickness were measured. ResultsIn the CH-CWI group only, the MVC-ISO, CMJ height, and ROM did not decrease significantly post-exercise, whereas all of these decreased in the other three groups. Muscle soreness at palpation, contraction, and stretching significantly increased post-exercise in all groups. Echo intensity and tissue hardness did not increase significantly in the CH-CWI group. ConclusionsCH-CWI stimulated recovery from impairments in MVC-ISO torque, CMJ height, knee-flexion ROM, tissue hardness, and echo intensity. These findings indicate that CH-CWI can promote recovery after eccentric exercise.

Prediction of Laminar Burning Speed of Propane/Hydrogen/Air Mixtures Using Power-Law Correlation and Two Machine Learning Models

Abstract Propane (C3H8) and hydrogen (H2) are regarded as alternative fuels that are favorable to the environment. Hydrogen gas's low energy density, storage, and transportation are the main issues with using it as an alternative fuel. Addition of hydrogen gas in the combustion of propane will also improve flame stability, broaden lean flammability limits, and reduces pollutant emissions. Thus, utilizing propane and hydrogen mixtures as fuel is a good choice. Laminar burning speed is a fundamental property of a combustible mixture and can be used to provide information regarding the mixture’s reactivity, exothermicity, and diffusivity. In this study, power-law correlation and machine learning methods were used to create models that predict the laminar burning speed of propane/hydrogen/air mixtures at various states. Two machine learning models are artificial neural network (ANN) and support vector machine (SVM). The data were generated by using CANTRA code and a chemical kinetic mechanism. For a wide variety of input values, the models were able to determine the laminar burning speed with great accuracy. The ANN model yields the best performance. The main advantage of these models is the noticeably faster computing time when compared to chemical reaction mechanisms.

Uji Performa Mesin Bensin dengan Sistem Injeksi Berbahan Bakar HCNG

Compressed Natural Gas (CNG) is an alternative renewable fuel gasoline replacement. However, due to the low heating value, the use of CNG in the engine will reduce its performance. The addition of hydrogen gas in CNG namely hydrogen-enriched compressed natural gas is expected to increase the power of the motor. This study aims to analyze the effect of hydrogen concentration on the performance of a CNG gasoline engine. The research was conducted on the engine with an indirect fuel injection system with a volume of 124,9 cc. The parameter of the engine that measured is torque, effective power, specific fuel consumption, and effective thermal efficiency. The results showed that the small percentage of hydrogen in CNG could increase the power of the gasoline engine. Power and efficiency reach a maximum of 10% hydrogen concentration. Increasing the proportion of hydrogen in CNG fuel above 10% will significantly reduce engine torque and power. Engine performance at optimal conditions with 10% hydrogen results in torque of 2.71 Kg.m at 670 rpm, effective power of 3.28 Ps at 1055 rpm, SFCe 0.17 Kg / Ps. Hours at 770 rpm and 33.62% effective thermal efficiency at 770 rpm

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.

Influence of the Thermodynamic Characteristics of the Combustion Process on Vehicle Emissions in Spark-Ignition Engines

The paper deals with the influence of the thermodynamic characteristics of the combustion process on toxicity in spark-ignition engines using the example of the UIT-85 single-cylinder unit. The studies were conducted on compressed natural gas and compressed natural gas with the addition of hydrogen gas. Also shown is the relationship of exhaust toxicity with the flame conductivity characteristic, reflecting the intensity of the combustion process in the flame front.

Improving the biomethane yield from food waste by boosting hydrogenotrophic methanogenesis

Anaerobic digestion of food waste is usually impacted by high levels of VFAs, resulting in low pH and inhibited methane production from acetate (acetoclastic methanogenesis); however, this could be harnessed for improving methane production via hydrogenotrophic methanogenesis (biomethanation). In this study, batch anaerobic digestion of food waste was conducted to enhance biomethanation by supplying hydrogen gas (H2), using a gas mixture of 5%-H2 and 95%-N2. The addition of H2 influenced a temporal microbial shift in substrate utilisation from dissolved organic nutrients to H2 and CO2 and was perceived to have enhanced the hydrogenotrophic methanogenic activity. As a result, with the release of hydrogen as degradation progressed (secondary fermentation) hydrogenotrophic methanogenesis was further enriched. This resulted in an enhancement of the upgrading of the biogas, with a 12.1% increase in biomethane (from 417.6 to 468.3 NmL-CH4/gVSadded) and 38.9% reduction in CO2 (from 227.1 to 138.7 NmL-CO2/gVSadded). Furthermore, the availability of hydrogen gas at the start of the process promoted faster propionate degradation, by the enhanced activity of the H2-utilisers, thereby, reducing likely propionate-induced inhibitions. The high level of acidification from VFAs production helped to prevent excessive pH increases from the enhanced hydrogenotrophic methanogenic activity. Therefore, it was found that the addition of hydrogen gas to AD reactors treating food waste showed great potential for enhanced methane yield and biogas upgrade, supported by VFAs-induced pH buffer. This creates the possibility to optimise hydrogenotrophic methanogenesis towards obtaining biogas of the right quality for injection into the gas grid.

Photocatalytic hydrogenation of nitroarenes using Cu1.94S-Zn0.23Cd0.77S heteronanorods

Catalytic hydrogenation is an important process in the chemical industry. Traditional catalysts require the effective cleavage of hydrogen molecules on the metal-catalyst surface, which is difficult to achieve with non-noble metal catalysts. In this work, we report a new hydrogenation method based on water/proton reduction, which is completely different from the catalytic cleavage of hydrogen molecules. Active hydrogen species and photo-generated electrons can be directly applied to the hydrogenation process with Cu1.94S-Zn0.23Cd0.77S semiconductor heterojunction nanorods. Nitrobenzene, with a variety of substituent groups, can be efficiently reduced to the corresponding aniline without the addition of hydrogen gas. This is a novel and direct pathway for hydrogenation using non-noble metal catalysts.

Determination of vibration characteristics of a compression ignition engine operated by hydrogen enriched diesel and biodiesel fuels

Biodiesel is a renewable fuel that is produced from vegetable oils and animal fats. The main advantage of biodiesel is its cleaner characteristic after the combustion. Due to its promising effect on the environment, the use of biodiesel is increasing day by day. Therefore, other effects of biodiesel fuels on internal combustion engine must be investigated by researchers. Mechanical vibration of a machine is a highly important phenomenon for safety. Moreover, in some applications, it directly influences human comfort. The vibration of a vehicle through its internal combustion engine has gained great importance due to the effect on vehicle structure parts and passenger comfort as well as driving safety. In this study, a diesel engine was fuelled with alternative fuel and conventional diesel fuels. Pure conventional diesel fuel was selected as reference fuel to compare vibration characteristics of the engine with respect to various biodiesel fuels. In the study, biodiesel was produced from waste cooking oil. Hydrogen was also added through intake air through experiments. The results indicated that addition of biodiesel in conventional diesel fuel lowered the engine block vibration. Moreover, the addition of hydrogen gas further decreased the engine vibration both with conventional diesel engine and biodiesel blend.

Photocatalytic hydrogenation of furan to tetrahydrofuran in alcoholic suspensions of metal-loaded titanium(iv) oxide without addition of hydrogen gas.

The use of metal co-catalysts broadens the application of photocatalytic reduction without the use of dihydrogen (H2) gas. We examined photocatalytic hydrogenation of furan, a representative heterocyclic compound and a compound derived from biomass, in alcoholic suspensions of metal-loaded titanium(iv) oxide (TiO2) under a H2-free condition and we found that furan was almost quantitatively hydrogenated to tetrahydrofuran with a high apparent quantum efficiency of 37% at 360 nm when palladium was used as a co-catalyst. Effects of different metal co-catalysts, different amounts of the co-catalyst, the type of TiO2, the type of alcohol, light wavelength and reusability for furan hydrogenation were investigated. Based on the results, the functions of TiO2 and the co-catalyst and the reaction process are discussed.

Development of a Dual Plasma Desorption/Ionization System for the Noncontact and Highly Sensitive Analysis of Surface Adhesive Compounds.

We developed a dual plasma desorption/ionization system using two plasmas for the semi-invasive analysis of compounds on heat-sensitive substrates such as skin. The first plasma was used for the desorption of the surface compounds, whereas the second was used for the ionization of the desorbed compounds. Using the two plasmas, each process can be optimized individually. A successful analysis of phenyl salicylate and 2-isopropylpyridine was achieved using the developed system. Furthermore, we showed that it was possible to detect the mass signals derived from a sample even at a distance 50 times greater than the distance from the position at which the samples were detached. In addition, to increase the intensity of the mass signal, 0%–0.02% (v/v) of hydrogen gas was added to the base gas generated in the ionizing plasma. We found that by optimizing the gas flow rate through the addition of a small amount of hydrogen gas, it was possible to obtain the intensity of the mass signal that was 45–824 times greater than that obtained without the addition of hydrogen gas.

Graphene Films Prepared Using Energetic Physical Vapor Deposition

ABSTRACT Carbon films were energetically deposited onto copper foil using the physical vapor deposition technique filtered cathodic vacuum arc. Raman spectroscopy and x-ray absorption spectroscopy showed that high quality graphene films of uniform thickness can be deposited onto copper foil at temperatures of 850 °C. The films can be prepared at high deposition rates (∼1 nm/min) and were comparable to graphene films grown at 1050 °C using chemical vapor deposition. This lower growth temperature was made possible by the energetic carbon flux which assisted the arrangement of carbon atoms into graphene layers on the Cu growth surface. Floating substrate potential was found to produce the highest quality graphene and the addition of hydrogen gas during film growth resulted in more defective films.

Hydrogen protects auditory hair cells from cisplatin-induced free radicals

Cisplatin is a widely used chemotherapeutic agent for the treatment of various malignancies. However, its maximum dose is often limited by severe ototoxicity. Cisplatin ototoxicity may require the production of reactive oxygen species (ROS) in the inner ear by activating enzymes specific to the cochlea. Molecular hydrogen was recently established as an antioxidant that selectively reduces ROS, and has been reported to protect the central nervous system, liver, kidney and cochlea from oxidative stress. The purpose of this study was to evaluate the potential of molecular hydrogen to protect cochleae against cisplatin. We cultured mouse cochlear explants in medium containing various concentrations of cisplatin and examined the effects of hydrogen gas dissolved directly into the media. Following 48-h incubation, the presence of intact auditory hair cells was assayed by phalloidin staining. Cisplatin caused hair cell loss in a dose-dependent manner, whereas the addition of hydrogen gas significantly increased the numbers of remaining auditory hair cells. Additionally, hydroxyphenyl fluorescein (HPF) staining of the spiral ganglion showed that formation of hydroxyl radicals was successfully reduced in hydrogen-treated cochleae. These data suggest that molecular hydrogen can protect auditory tissues against cisplatin toxicity, thus providing an additional strategy to protect against drug-induced inner ear damage.

Fabrication of Titanium-Based Hard Coatings by Atmospheric Microplasma-Metal Organic Chemical Vapor Deposition Using Titanium Tetraisopropoxide

The atmospheric microplasma metal organic chemical vapor deposition (AP-MOCVD) using titanium (IV) tetraisopropoxide (TTIP) as a metal alkoxide titanium source was investigated for depositing TiC and TiN hard coatings on stainless steel rods for improving the tool life of electroplated diamond tools. The components and morphology of the coating deposited by microplasma AP-MOCVD with several gas sources and different processes was observed and analyzed. The titanium-based hard coatings composed of TiC, TiN, and TiO2 was successfully obtained by microplasma AP-MOCVD using TTIP as a metal alkoxide titanium source with mixed gases (CH4, N2, H2, and Ar). For the fabrication of titanium-based coatings (TiC, TiN) by microplasma AP-MOCVD, it is important that the carbon and oxygen content, which are components of TTIP, are reduced. The addition of hydrogen gas in the microplasma AP-MOCVD process, followed by nitriding effectively reduces the carbon and oxygen content in the coating.

Formation of nanodiamonds at near-ambient conditions via microplasma dissociation of ethanol vapour

Clusters of diamond-phase carbon, known as nanodiamonds, exhibit novel mechanical, optical and biological properties that have elicited interest for a wide range of technological applications. Although diamond is predicted to be more stable than graphite at the nanoscale, extreme environments are typically used to produce nanodiamonds. Here we show that nanodiamonds can be stably formed in the gas phase at atmospheric pressure and neutral gas temperatures <100 °C by dissociation of ethanol vapour in a novel microplasma process. Addition of hydrogen gas to the process allows in flight purification by selective etching of the non-diamond carbon and stabilization of the nanodiamonds. The nanodiamond particles are predominantly between 2 and 5 nm in diameter, and exhibit cubic diamond, n-diamond and lonsdaleite crystal structures, similar to nanodiamonds recovered from meteoritic residues. These results may help explain the origin of nanodiamonds in the cosmos, and offer a simple and inexpensive route for the production of high-purity nanodiamonds.

Insertion of nanocrystalline diamond film and the addition of hydrogen gas during deposition for adhesion improvement of cubic boron nitride thin film deposited by unbalanced magnetron sputtering method

Cubic boron nitride (c-BN) thick film growth was attempted by the addition of hydrogen for residual stress reduction and by using a nanocrystalline diamond (NCD) buffer layer for stabilizing the turbostratic boron nitride interfacial layer. The c-BN films were deposited by the unbalanced magnetron sputtering method. Thin (100μm) Si strips (3×40mm2) were used as substrates. A boron nitride target was used, which was connected to a radio frequency power supply at 400W. High frequency power connected to a substrate holder was used for self-biasing of −40V. The deposition pressure was 0.27Pa with a flow of Ar (18sccm)–N2 (2sccm) mixed gas. Hydrogen gas of 2sccm was added to the Ar–N2 mixed gas. The effect of the addition time of the hydrogen to the Ar–N2 gas during deposition was investigated and found to be critical to the occurrence of the delamination of the c-BN film on the NCD buffer layer. As the addition of the hydrogen was delayed, the delamination started later. C-BN film of 3μm thickness adherent to the substrate was obtained.

Rhodium catalyzed hydroformylation with formaldehyde and an external H2-source

The efficiency of the syngas-free rhodium catalyzed hydroformylation of olefins with formaldehyde can be significantly improved by the addition of hydrogen gas or formic acid.

Field emission techniques for studying surface reactions: Applying them to NO–H2 interaction with Pd tips

The adsorption of NO and its reaction with H(2) over Pd tips were investigated by means of field ion microscopy (FIM) and pulsed field desorption mass spectrometry (PFDMS) in the 10(-3)Pa pressure range and at sample temperatures between 400 and 600K. By varying the H(2) partial pressure while keeping the other control parameters constant, the NO+H(2) reaction over Pd crystallites is shown to exhibit a strong hysteresis effect. The hysteresis region narrows with increase in temperature and the H(2) pressures delimiting this hysteresis decrease as well. Abrupt transformations of the micrographs are observed by FIM from bright to dark patterns and vice versa. These transformations define the hysteresis region. The collected data allow establishing a novel kinetic phase diagram of the NO+H(2)/Pd system within the range of temperatures and pressures indicated. The observed features are correlated with a local chemical analysis by means of field pulses. NO(+) seems to be the dominating imaging species under all conditions. At high relative H(2) pressures (the "hydrogen-side"), H atoms seem to diffuse subsurface. This process is blocked at lower H(2) pressure (the "NO-side") due to NO(ad) and O(ad) accumulation on the surface. Probe-hole measurements with field pulses indicate that the Pd surface undergoes oxidation as revealed by the occurrence of PdO(2)(+) species in the mass spectra.

Effects of deposition temperature on the effectiveness of hydrogen doping in Ga-doped ZnO thin films

Gallium-doped zinc oxide thin films were prepared on glass substrates by dc magnetron sputtering under various hydrogen contents in sputtering ambient. The carrier concentration of the films deposited at low-temperatures (80 and 160 °C) was increased due to the incorporation of hydrogen atoms, acting as shallow donors. A low resistivity of 4.0×10−4 Ω cm was obtained for the film grown at 160 °C with H2 10%, which has a carrier concentration of 8.2×1020/cm3. The beneficial effect of hydrogen doping was not observed for the films deposited at 270 °C. Both carrier concentration and mobility were decreased by the addition of hydrogen gas in the sputtering ambient. Variations in the electrical transport properties upon vacuum annealing showed that the difference is attributed to the thermal stability of interstitial hydrogen atoms in the films. The hydrogen incorporation was found to induce the lattice expansion and the free carrier absorption in near infrared range. The investigation of the structural and optical properties of the films upon annealing also revealed that the incorporated hydrogen atoms are unstable at high temperature, which is consistent with the results obtained in the electrical properties.