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Pipeline welds are subjected to pre-straining based on designs for the installations. So, the present work deals with the effects of hydrogen and pre-straining on the mechanical properties of weld metal. According to the results, the weld metal microstructure was mainly comprised of acicular ferrite. Expectedly, the highest diffusible hydrogen belonged to the 33.6% pre-strained specimen which was equal to 5.1E-06 mol cm−3. Due to increase in hydrogen traps, the diffusible hydrogen content elevated at higher pre-straining. The largest variations in hydrogen blistering were observed in the 33.6% pre-strained specimen. The number of hydrogen cracks was increased by 18–23 percent with the most variations in the 33.6% pre-strained specimen. The hardness of weld metal specimen was increased by 5–10 percent at higher pre-straining in the presence of hydrogen. Hence, it could be concluded that the concurrent presence of hydrogen and pre-straining led to increase in the hardness and hydrogen defects into the weld metal.

Atomic hydrogen is a fundamental constituent of galaxies, and is the primary fuel for star formation. Understanding how the atomic hydrogen content of galaxies evolves with time is thus critical to understanding galaxy evolution. In this article, we discuss how one measures the atomic hydrogen content of distant galaxies, and what these measurements tell us about the evolution of our Universe.

Examination of fractures of rolling bearings from steel 8Kh4V9F2-Sh (EI347-Sh) is used to assess the effect of production factors on the operating capacity of bearings under elevated loads. The microstructure and fractures of the steel are analyzed. The compressive stresses and the contents of the general and diffusion-mobile hydrogen are determined. It is shown that a fatigue crack appears in the material of the bearing in service in the case of an elevated hydrogen content and an unfavorable fiber structure.

Pores in the AlSi10Mg products fabricated by laser powder bed fusion (LPBF) decrease the density of components. To study the mechanism of the formation and evolution of hydrogen pores, a model based on molecular dynamics (MD) is built. The influence of initial hydrogen content, heating time, and cooling time on the porosity is analyzed. Low initial hydrogen content, long cooling time, and appropriate heating time are beneficial to decrease the porosity of LPBF-fabricated products. When the heating time is 40 ps, the cooling time is 200 ps and initial hydrogen content is 0.081%; porosity can be reduced to 3.01%.

The hydrogen-assisted cracking susceptibility of modified 9Cr-1Mo steel weld is evaluated by Y-groove and gapped bead-on-plate test. It is found that a combination of pre + post heat is able to prevent cracking. However, the pre + post heat temperature combination determined from G-BOP test to prevent cracking (200 °C) is found to be higher than that in Y-groove test (100 °C). This is attributed to the higher weld restraint experienced in G-BOP than Y-groove test. For both the tests, the weld metal is found to be more susceptible to cracking than the heat affected zone. In addition to the diffusible hydrogen content of the welding consumables, diffusible hydrogen present in the G-BOP specimens prepared with different preheating and combinations of pre + post heat is also estimated by maintaining identical cooling conditions. The diffusible hydrogen in the weld for which no cracking is reported for G-BOP test (200 °C pre + post heat) is less than 1 ml/100 g. Considering the high restraint conditions present in the G-BOP test, it can be concluded that to prevent HAC in P91 steel, the choice of welding parameters (hydrogen content in welding consumable, heat input, pre/post-heating) should be such that diffusible hydrogen in the weld is brought down to below 1 ml/100 g.

JSW Steel Ltd. supplies hydrogen-sensitive rail steels blooms for the manufacture of steel rails for Euro-rail application through AFERPI, Lucchini. The hydrogen distribution in the production of two high-carbon near-eutectoid rail steel grades VAR89S (typically, 0.70%C–0.3%Si–1.1%Mn–0.015%S) and VAR101 (typically, 0.80%C–0.42%Si–1.01%Mn–0.65%Cr–0.005%S) has been examined from the steel making stage to the as-cast blooms. In the steel grade VAR89S, the hydrogen distribution has been examined in the hot-rolled steel rails at different locations. The steel making involves primary steel making using energy optimizing furnace, ladle furnace followed by vacuum degassing. The hydrogen content before secondary steel making varies between 3 and 5.5 ppm H, which decreases to less than 1.5 ppm H after vacuum degassing. The steel picks up hydrogen, when transferred to tundish to a value, less than 2.5 ppm, associated with moisture in spray mass and tundish compound. On solidification in continuous casting, the hydrogen level decreases to less than 1.6 ppm H, which is associated with lowering of hydrogen solubility associated phase transformation of molten steel to solid. When the bloom is converted to steel rails, the hydrogen level further decreases due to the increased surface area-to-volume ratio. The final hydrogen levels in steel rails are

The hydrogen-induced delayed cracking (HIDC) behaviors of two types of 1500 MPa grade hot stamping steels (HSSs) have been investigated by the method of slow strain rate tensile test and hydrogen permeation, where one is manufactured by compact strip production (CSP) process which is a revolution to the traditional HSS and the other by the traditional cold rolling process. The results show that the performance of HSS produced by CSP is superior to that of the traditional HSS, due to lower hydrogen embrittlement index, lower hydrogen diffusion coefficient and lower hydrogen content. It has been found that HIDC behavior is closely associated with inclusions. The inclusions of HSS produced by CSP are mainly spherical Al–Ca–O and CaS, while the inclusions in the traditional HSS are TiN + Al2O3 + MnS with sharp edges and corners. Based on these results, the influence of composition, shape and distribution of inclusions in HSS on HIDC and the mechanism of HIDC from the perspective of inclusions were analyzed and discussed.

We develop a mathematical model and software module for the evaluation of the accumulation of defects with regard for hydrogen diffusion. The process is modeled by using two methods: by the Kachanov– Rabotnov–Lokoshchenko equations with two parameters (damage and hydrogen content) and the energy approach. For this purpose, we use Bridgman specimens with and without regard for the influence of hydrogen. The results of calculations obtained according to these two approaches are in satisfactory agreement with the experimental data. However, the energy approach gives a twicesmaller error.

Changes to the monotectoid transition in the niobium-hydrogen system due to the substitution of modest amounts of niobium with tantalum have been assessed via differential scanning calorimetry. Specimens of the alloy-hydrogen system, of varying hydrogen content, were analyzed over the temperature range from 323 to 398 K. From differential scanning calorimetric analysis, the phase transition temperature and the energy change due to the phase transition were quantified. The results show that the presence of tantalum significantly alters both the temperature and compositional characteristics of the monotectoid equilibrium. Relative to the niobium-hydrogen system, tantalum caused a decrease to the monotectoid transition temperature and a decrease in the width of the monotectoid horizontal boundary.

Hydrogen content in the diffusible range and beyond a critical level in steel is detrimental to the formation of hydrogen flakes that show up in ultrasonic testing. It is observed that the hydrogen content in any hot-rolled steel has a gradient with lowest hydrogen at the surface and higher towards the core. This is associated with the secondary phase transformation of high hydrogen-soluble austenite phase to a low-soluble ferrite phase, occurring last towards the core. Anti-flaking heat treatment was carried out in a flake-sensitive pearlitic rail steel grade, VAR89S, with an initial hydrogen level of 1.86 ppm at the core and 1.58 ppm in the surface of a 160-mm diameter hot-rolled bar. The heat treatment involved holding at 650 °C for times varying between 8 and 36 h, which decreased the hydrogen content. The decrease in hydrogen during anti-flaking heat treatment was correlated using Fick’s law model which took into account the initial hydrogen gradient across the bar cross section. The model predicted the experimental trend for hydrogen distribution at surface, mid-radius, and core. The hydrogen distribution at surface showed higher than predicted values, which could be attributed to the carbide spheroidization at the surface.

This study uses first-principles calculations to investigate the effect of hydrogen on the chemical driving force of the transformation of iron from the face centered cubic (FCC) to hexagonal close packed (HCP) phase. The minimum energy path from FCC to HCP phases shows that FCC becomes stable with increasing hydrogen content. Furthermore, the energy difference between the FCC and HCP phases is observed to be smaller in Fe2H than in Fe throughout the temperature region. These results clearly explain the observed anomalous suppression of the martensitic transformation in the hydrogen-charged steel.

The experimental evidence for the contraction of volume of gold implanted with hydrogen at low doses is presented. The contraction of lattice upon the addition of other elements is very rare and extraordinary in the solid-state, not only for gold but also for many other solids. To explain the underlying physics, the pure kinetic theory of absorption is not adequate and the detailed interaction of hydrogen in the lattice needs to be clarified. Our analysis points to the importance of the formation of hydride bonds in a dynamic manner and explains why these bonds become weak at higher doses, leading to the inverse process of volume expansion frequently seen in metallic hydrogen containers., Hydrogen can be absorbed into various metals, but generally causes the metals to expand. Here the authors show that when hydrogen is dynamically bound to the lattice, as in dilute Au:H solutions, the gold contracts accordingly.

The quality of rolled product of high-strength low-carbon steel prepared from slabs using an improved reduced heat treatment regime is studied. It is shown that use of this heat treatment regime for slabs of high-strength vessel steel (Cr–4Ni–Mo–V composition), including a high-temperature tempering operation, with a hydrogen content in molten steel not more than 1.8 ppm provides rolled product quality at the level of metal of standard production. The use of the new regime makes it possible to reduce significantly the production cycle duration.

Poisoning the illicit materials by a neutron absorber leads to false detection when the detection is relied on combined thermal neutron activation and fast neutron activation to identify the elements of interest. The use of adjacent transmission thermal neutron detector for verifying the presence of neutron poisons and to trigger an alarm was investigated experimentally and using MCNP calculations. The illicit material of high hydrogen content will affect the detector response in the presence or absence of poisons.

Results are given for research aimed at improving the quality of large tonnage flat ingots under RUSAL Joint Company (Krasnoyarsk) conditions as a result of reducing the hydrogen content within them to less than 0.1 cm3/100g. For this purpose, under production conditions the change in molten aluminum alloys series 1XXX hydrogen content is analyzed in the main stages from the aluminum electrolyzer to the casting machine. Production operations are determined within which there is significant melt impregnation with hydrogen. Research precision is provided by using a developed procedure for molten sample collection in the main production operations and considering the specific nature of production. Technical solutions are proposed from research results aimed at reducing melt hydrogen expansion.

The bulk Ti–6Al–4V alloy was hydrogenated at the temperature range of 723–973 K, and the hydrogen absorption characteristics and hydrogen absorption kinetics were investigated. The results show that there are two types of hydrogen absorption characteristics at different temperatures. The hydrogen content decreases, and the time reaching reaction equilibrium is shorten with the isothermal hydrogenation temperature increasing. Meanwhile, the mechanism of the hydrogen absorption kinetics is different at different temperatures. The incubation period exists at the initial hydrogen absorption stage below 823 K, and Ka2 (the reaction rate constant of Stage 2) ≫ Ka1 (the reaction rate constant of Stage 1). And there is no incubation period over 823 K, Ka1 ≫ Ka2.

Superior mechanical properties of copper are needed in industries to meet high application requirement. In this study, an electroformed copper with superior mechanical properties is achieved by using a simple ultra-low-concentration copper sulfate bath containing neither chloride nor organic additives. Copper deposits obtained in the copper sulfate concentrations ranging from 30 to 60 g/L exhibit high tensile strength and elongation simultaneously. A maximum tensile strength of 256 MPa is achieved, with an elongation ratio of 31%, at a copper sulfate concentration of 30 g/L, while a maximum elongation ratio of 43% is achieved, with a tensile strength of 216 MPa, at a concentration of 50 g/L. It has been found that the copper sulfate concentration affected the hydrogen content, grain arrangement and orientation index of copper deposits which determine their mechanical properties. When the copper sulfate concentration is less than 30 g/L, the excessive hydrogen content of the deposits thus produced leads to poor compactness and inferior mechanical properties. At concentrations over 50 g/L, a disordered arrangement of grains and a significant increase in the peak of (111) lead to an increase in the tensile strength but a decrease in the elongation ratio. This approach provides an effective and economical method for the copper deposits achieving superior mechanical properties.

Cracking residual fuel oil separated from a mixture of Azerbaijanian crude oils using catalysts based on aluminum plant sludges containing up to 50-70% Fe2O3 was investigated. It is shown that the yield of liquid products, including motor fuels, upon residual fuel oil cracking at 550 °C rises to 80 and 70 wt. %, respectively. Steam gasification of carbonized and partially reduced catalyst allows production of gas with hydrogen content of up to 72.84 vol. %.

Flake is an irreparable crack type defect in many huge steel products, especially in heavy forging. Lots of previous studies have revealed that flake is usually originated at cavities within heavy forging. In addition, whether it is generated and what size after it is formed both largely depend on the hydrogen pressure within the cavity. However, the most part of previous studies only related cavity hydrogen pressure to steel hydrogen concentration, and few studies considered the metal forming effect. In this paper, the relationship between cavity hydrogen pressure and metal forming process of heavy forging is addressed from a simulation perspective. Different from previous research, this paper wants to emphasize the importance of metal forming process in the flake formation. There are four parts in this paper. We start with a brief introduction to the flake and the importance of cavity hydrogen pressure in its formation. Then, we propose a cavity hydrogen pressure calculation model. After that, the simulation results and discussions are provided. We end the study with the conclusion. We find in our research that metal forming has a great influence on cavity hydrogen pressure, especially with large deformation. Based on these findings, we may conclude that flake formation not only depends on the steel hydrogen content, but also very depends on the way of forming. Admittedly, what we have discussed in this study is far from complete. And some improvements we want to make in our further research include (1) studying the influence of metal forming on flake formation in micro-scale, such as in grain scale; (2) verifying the simulation results with experiment; and (3) considering the hydrogen diffusion process in metal forming process.

The gaseous reduction of magnetite ore concentrates was studied using CO-CO2 and CO-CO2-H2 gas mixtures at different temperatures and gas compositions. The reduction of magnetite ore by CO-CO2 gas mixture was examined at temperatures 973 K to 1173 K (700 °C to 900 °C) at CO/CO2 ratio 80/20, and at varied CO/CO2 ratio from 60/40 to 85/15 at 1023 K (750 °C). In the reduction of magnetite ore by CO-CO2-H2 gas mixture, temperature was 1173 K (800 °C) and hydrogen content changed from 5 to 25 vol pct at constant CO/CO2 ratio of 80/20. Reduction of magnetite ore did not go to completion in both CO-CO2 and CO-CO2-H2 gas mixtures. Addition of H2 to the CO-CO2 gas mixture accelerated the reduction in the first 10 to 30 minutes of reaction. However, the degree of reduction by gas containing 5 to 25 vol pct H2 after 60 to 120 minutes of reaction was in the range 60 to 65 pct, while the degree of reduction by CO-CO2 gas (80 vol pct CO) after 120 minutes of reaction was close to 70 pct. Significant swelling of magnetite ore pellets was observed in the reduction by CO-CO2 gas mixture. Addition of H2 to the CO-CO2 gas mixture decreased swelling. Swelling of magnetite ore during the reduction was attributed to the breakout of iron layer caused by the increase of the inner pressure in the voids at the wustite/iron phase boundary.

Iron and steels are extensively used as structural materials, and have three primary phase structures: Body-centered cubic (bcc), face-centered cubic (fcc), and hexagonal closed-packed (hcp). Controlling phase stabilities, especially by the use of interstitials, is a universal method that provides a diverse variety of functional and mechanical properties in steels. In this context, hydrogen, which can act as an interstitial species in steels, has been recognized to promote phase transformation from fcc to hcp. However, we here report a dramatic effect of interstitial hydrogen that suppresses this hcp phase transformation. More specifically, the fraction of hcp phase that forms during cooling decreases with increasing diffusible hydrogen content. This new finding opens new venues for thermodynamics-based microstructure design and for development of robust, strong, and ductile steels in hydrogen-related infrastructures.

Continental rifting is thought to occur in particularly hydrous plates. Magnetotelluric images of the East African Rift, however, reveal that the rift is anhydrous, implying that hydrogen content is not a primary control on plate strength.

In the frame of reference fluence measurements with a proton recoil telescope, solid layers with an areal density up to 25 mg cm−2 and with well-known and stable hydrogen content above 12 % were requested on circular tantalum discs. Tristearin layers with an areal density of 10 mg cm−2 were prepared by physical vapour deposition. The thickness was determined by accurate weighing. The hydrogen content of both starting and deposited material was measured by combustion analysis and the accuracy of this characterization method was good enough to demonstrate that the hydrogen content remains unchanged under thermal treatment.

Hydrogen plays an important role in the formation of quench cracks of structural steels. To clarify hydrogen absorption and desorption during heat treatment of AISI 4140 steel, thermal desorption spectrometry (TDS) analysis was carried out for the specimens in the as-rolled, as-quenched, and quenched and tempered conditions. Results show that hydrogen content increased from 0. 127 × 10−6 in the as-rolled specimen to 0. 316 × 10−6 in the as-oil-quenched specimen. After tempering at 200 °C, the hydrogen content in the oil-quenched specimen decreased to 0. 155 × 10−6, and the peak temperature of hydrogen desorption increased from 200 to 360 °C. From the dependence of hydrogen content in the as-quenched specimens on austenitizing time, it can be deduced that hydrogen absorption occurs during austenitizing. The simulation of hydrogen absorption contributes to a better understanding on the distribution of hydrogen during the heat treatment in structural steels.

As a promising candidate material for hydrogen storage, ammonia borane (NH3BH3) has attracted significant interest in recent years due to its remarkably high hydrogen content. Subjecting this material to high pressure not only enables the formation of novel phases and compounds with exotic properties, but also improves our basic understanding of material’s behavior at different levels of atomic and molecular interactions. This review focuses on the perspective of high-pressure chemical hydrogen storage related to NH3BH3-based materials. Four main aspects are discussed: the structures and bonding of NH3BH3 over a wide pressure–temperature space, thermolysis of NH3BH3 at high pressure, the formation of a novel high-pressure H-rich compound as a result of storage of additional molecular H2 in NH3BH3, and the potential rehydrogenation of the thermally decomposed NH3BH3 under the extreme of pressure.

The influence of temperature on the hydrogen diffusion behavior in X80 pipeline steel during stacking for slow cooling was studied using electrochemical penetration method, the temperature field and the hydrogen diffusion in this pipeline steel during stacking for slow cooling were simulated by ABAQUS finite element method (FEM) software. The results show that in this process there is a reciprocal relationship between the natural logarithm of hydrogen diffusion coefficient and temperature. The cooling rate decreases gradually with the increase of steel plate thickness. The hydrogen content is higher at high temperature (500–400 °C) than that in low temperature region (300–100 °C). The FEM simulation results are consistent with the experimental ones, and the model can be used to predict the hydrogen diffusion behavior in industrial production of X80 pipeline steel.

A series of reduction experiments of iron ore pellets with hydrogen, carbon monoxide and their mixture were carried out in a laboratory scale shaft furnace. The sticking behavior accompanying reduction of iron ore pellets was investigated. And morphology of the sticking interface forming during reduction was analyzed by SEM equipped with EDS. In order to evaluate the effects of the temperature and gas composition on sticking properties, reduction of iron ore pellets were conducted at 800–1000 °C. The results show that the sticking strength of the pellets increases with temperature, however, decreases with hydrogen content in reducing gas. For an efficient shaft furnace operation in direct reduction (DR), relative prevention of sticking such as coating of pellets was also developed to solve sticking problem. The results show that CaO is a suitable material for the coating method.

Experimental and numerical studies were carried out for the behavior of hydrogen in a three-phase electroslag furnace using double electrode series technique during electroslag remelting (ESR) process. The effect of water vapor content of furnace gas on the hydrogen content of ingots was studied through the “gas-slag-metal” osmosis experiment. Based on the experimental results, a mathematical model was set up for the behavior of hydrogen pick-up during ESR process. Then the flow of furnace gas during ESR process was studied through a commercial code FLUENT, and the relationship between the water vapor content of furnace gas and argon gas flux in practical production was derived. Finally, the desired reasonable argon gas flow for controlling the hydrogen content of ingots below 2×10 −6 in practice was obtained.

Calcium borohydride is a potential candidate for onboard hydrogen storage because it has a high gravimetric capacity (11.5 wt.%) and a high volumetric hydrogen content (∼130 kg m(-3)). Unfortunately, calcium borohydride suffers from the drawback of having very strongly bound hydrogen. In this study, Ca(BH₄)₂ was predicted to form a destabilized system when it was mixed with LiBH₄, NaBH₄, or KBH₄. The release of hydrogen from Ca(BH₄)₂ was predicted to proceed via two competing reaction pathways (leading to CaB₆ and CaH₂ or CaB₁₂H₁₂ and CaH₂) that were found to have almost equal free energies. Using a set of recently developed theoretical methods derived from first principles, we predicted five new hydrogen storage reactions that are among the most attractive of those presently known. These combine high gravimetric densities (6.0 wt.% H₂) with have low enthalpies [approximately 35 kJ/(mol(-1) H₂)] and are thermodynamically reversible at low pressure within the target window for onboard storage that is actively being considered for hydrogen storage applications. Thus, the first-principles theoretical design of new materials for energy storage in future research appears to be possible.

This paper entails the results of the investigations undertaken to assess the oil potential of two lignite deposits, Rajpardi and Vastan, from Gujarat, western India. They are ‘Low rank B’ type lignite. Petrographically, they are enriched in huminite and are low in liptinite and inertinite. Their elevated hydrogen content, in relation to carbon, has probably made them perhydrous in nature and oil prone. The reactivity of these coals during liquefaction has also been discussed in the light of petrofactor. Good correlation has been noticed between oil yield and conversion (r2 = 0.999) in both the lignite deposits. The VRr (0.24–0.35% in both lignites), H/C atomic ratio (0.11–1.39 in Rajpardi and 1.09–1.88 in Vastan), reactive maceral content (91.6–99.8 vol % mmf in Rajpardi lignite and 75.5–99.7 vol % in Vastan lignite) and VMdaf (64.8–67.9 wt % in Rajpardi lignite and 42.1–80.0 wt % in Vastan lignite) of these lignites have a favourable range required for a coal to generate oil. Huminite is seen to play a vital role in conversion and maintains a good correlation with it. The calculations show that these lignites have a high conversion (> 95%) and oil yield (> 65%).

A shaft suddenly suffered fracture during the test of loading in three directions. The shaft was made from 30CrMnSiA steel. The failure cause was analyzed by visual, stereo, and scanning electron microscopic observations of appearance and fracture surface of the shaft, micro-area composition inspection, metallographic examination, and measurement of the hydrogen content. The results showed that the failure mechanism of the shaft was fatigue fracture resulting from hydrogen-induced intergranular microcracks. The hydrogen-induced cracks were mainly caused by abnormal pickling during production of the shaft.

The effects of hydrogen on the structure of Zr-based bulk metallic glasses were investigated by positron annihilation lifetime spectroscopy. Three lifetime components are identified, indicating the presence of three distinct size ranges for open volume defects in the glass. The concentration of the smallest sites identified as tetrahedral interstitial holes in the densely packed and the intermediate sites identified as flow defects, changes with hydrogen addition. The concentration of tetrahedral interstitial holes in Zr55Cu30Ni5Al10 alloys initially increases with the increase of hydrogen content. When Zr55Cu30Ni5Al10 alloys were prepared in Ar + 10%H2 atmospheres, the concentration of tetrahedral interstitial holes reaches a maximum, which may provide a more dense random-packed structure. For Zr57Al10Cu15.4Ni12.6Nb5alloys, the increase of hydrogen content causes a decrease in the concentration of tetrahedral interstitial holes and an increase in the concentration of flow defects.

The Seebeck coefficient of vapour grown carbon fibres and carbon fibres made from polyacryolytrile precursor has been studied as a possible parameter to control hydrogen storage inside. The sign of the Seebeck coefficient gives the sign of the dominant charge carriers in the fibres, and when hydrogen is absorbed by the carbonaceous material, mainly as H +, it acts as a positive charge carrier. A simple two-band electronic model has been considered to explain the influence of hydrogenation on the Seebeck's coefficient of these carbon microfibres. The most favourable condition for hydrogen adsorption is a moderately low pressure of hydrogen. Furthermore, it was observed that outgassing is more pronounced than expected in some types of fibres, thereby supporting the proposed presence of hydrogen generated during the manufacturing process. © Springer Science+Business Media, LLC 2012., The authors would like to thank the Spanish Ministry of Science and Innovation for funding via the Consolider Program (Project NANOTHERM CSD2010-00044).

The phase structure and hydrogen storage properties of LaMg3.70Ni1.18 alloy were investigated. The LaMg3.70Ni1.18 alloy consists of main LaMg2Ni phase, minor La2Mg17 and LaMg3 phases. The alloy can be activated in the first hydriding/dehydriding process, and initial LaMg2Ni, La2Mg17, and LaMg3 phases transfer to LaH2.34, Mg, and Mg2Ni phases after activation. The reversible hydrogen storage capacity of the LaMg3.70Ni1.18 alloy is 2.47 wt.% at 558 K, which is higher than that of the LaMg2Ni alloy. The pres sure-composition-temperature (PCT) curves display two hydriding plateaus, corresponding to the formation of MgH2 and Mg2NiH4. However, only one dehydriding plateau is observed, owing to the synergetic effect of hydrogen desorption between MgH2 and Mg2NiH4. The uptake time for hydrogen content to reach 99% of saturated state is less than 250 s, and 90% hydrogen can be released in 1200 s in the experimental conditions, showing fast kinetics in hydriding and dehydriding. The activation energies of the LaMg3.70Ni1.18 alloy are -51.5±1.1 kJ/mol and -57.0±0.6 kJ/mol for hydriding and dehydriding, respectively. The hydriding/dehydriding kinetics of the LaMg3.70Ni1.18 alloy is better than that of the Mg2Ni alloy, owing to the lower activation energy values.

The hydrogen content in aluminum melts at different temperature was detected. The structure in aluminum melts was investigated by molecular dynamics simulation. The first peak position of pair correlation function, atomic coordination number and viscosity of aluminum melts were calculated and they changed abnormally in the same temperature range. The mechanism of hydrogen absorption has been discussed. From molecular dynamics calculations, the interdependence between melt structural properties and hydrogen absorption were obtained.

The FLAPW-GGA band method is used to analyze the structural, electronic, and magnetic properties of rhodium hydrides RhHx depending on the hydrogen content (x = 0.25, 1.00, and 1.33). The RhH monohydride is a magnetic metal. A decrease in the hydrogen content in the system or formation of vacancies in the Rh sublattice results in a transition of RhHx to the non-magnetic state

Although many experiments have been performed to reduce the lunar soil by hydrogen, no systematic thermodynamic analysis has been developed to design and optimize these experiments. Applying a thermodynamic model to the system of simulant lunar soil and hydrogen, this study analyzes and discusses the thermodynamic behavior of the system in detail. The calculations demonstrate that iron is the only metal that can be extracted significantly from the lunar soil. The amount of hydrogen in the system drastically affects the processes of iron extraction and water production. However, the effect of system pressure can be neglected in the process. The yields of metallic iron and water from the lunar soil as functions of temperature and hydrogen content are investigated in this study. Additionally, the calculations explain the metallic iron on the surface of the moon from the thermodynamic point of view.

An artificial neural network (ANN) model has been developed to analyze and predict the correlation between tensile property and hydrogenation temperature and hydrogen content of hydrogenated Ti600 titanium alloy. The input parameters of the neural network model are hydrogenation temperature and hydrogen content. The output is ultimate tensile strength. The accuracy of ANN model was tested by the testing data samples. The prediction capability of ANN model was compared with the multiple linear regression approach and response surface method. The combined influence of inputs on the tensile property is also simulated using ANN model. It is found that excellent performance of the ANN model was achieved, and the results showed good agreement with experimental data. Moreover, the developed ANN model can be used as a tool to control the tensile property of titanium alloys.

A novel treatment method based on anaerobic digestion and in-situ electrohydrolysis of dairy bio-sludge was investigated in this article. The electrohydrolysis was carried out inside the anaerobic reactor using graphite anode and stainless steel cathode. The electrons released by the graphite anode combines with the proton released due to electrohydrolysis of fatty acids which resulted in the formation of hydrogen gas. The experiments were conducted using a DC power source under continuous and intermittent mode of input voltage ranging from 0.5 to 2.5 V for varying influent volatile solids concentration at a pH 5.3 ± 0.2. The results favored intermittent mode of input voltage rather than continuous supply. For an influent total solid concentration of 7% (64,120 mg/L VS), intermittent input voltage of 2 V, and a hydraulic retention time of 15 days resulted in a volatile solids and soluble COD removal efficiency of 83 and 74%, while the cumulative gas generation was 1,051 L with a hydrogen content of 72%.

This international round robin test served to scrutinize the procedures specified in ISO/DIS 3690:2009 for determining the diffusible hydrogen content in weld metals with bcc-lattice structure. It was specifically intended to check in what respect the specifications defined in the indicated standards for specimen preparation, storage and hydrogen analysis provide comparable measurement results. The round robin test is presented comprising comparative measurements at various degassing temperatures using hot extraction techniques and a thermal conductivity detector (TCD). A major focus of this investigation was the examination of the maximum degassing temperature for analysing the diffusible hydrogen in materials with bcc-lattice structure. The analyses were performed using two different stick electrodes and three different filler wires. As a significant result it was found that no deviations or increases, were detected in the measured contents of diffusible hydrogen for the investigated degassing temperatures ranging between 45 °C and 400 °C. Hydrogen analyses for contents below HD = 1.5 ml/100 g with the hot extraction techniques in conjunction with TCD applied in this study led to considerable relative standard deviations.

In this study, the effect of hydrogen on fatigue strength of high strength steels in the very high cycle fatigue regime was further discussed. It is found that the calculated results of fatigue strength by modified Murakami's expression are in good accordance with the experimental results in +/- 15% error band. The relationship between fatigue life (N(f)) and the ratio of granular-bright facet (GBF) to inclusion size (root A(GBF)/root A(inc)) for quenching and tempering (QT) specimens and pre-charged specimens by soaking (SK) and cathodic (CD) charging can be approximately expressed by root A(GBF)/root A(inc) = R(GBF)/R(inc) = 0.25N(f)(0.125); however, the value of root A(GBF)/root A(inc) for specimens pre-charged by high-pressure thermal hydrogen charging is obviously greater than that for QT specimens and pre-charged specimens by SK and CD charging at an identical N(f). The stress intensity factor range at the periphery of the GBF, Delta K(GBF), was calculated in this work. It is found that value of Delta K(GBF) is not a constant but approximately proportional to (root A(GBF))(1/3). Besides it is also found that Delta K(GBF) decreases with the increase of hydrogen content.

In order to explore the reason for the frequency explosion of spontaneous combustion coal gangue dump and get to know their explosion mechanism, established the experiment platform about spontaneous combustion coal gangue dump interoperable water. The gangue dump was heated using the external heat source, and rainy weather through water mist was simulated. Simulated experiment about explosion of spontaneous combustion coal gangue dump was carried out on the different conditions of the rainfall or not. The unusual gases produced in the course of gangue combustion and the changes in temperature were observed, and their impacts on the explosion of gangue dump were analyzed. The experimental results show that overall warming phenomenon of the gangue dump after watering occurred, the amount of H2 is three times than that before watering, and the amount of CO is far greater than that on the conditions of no-watering, at the same time combining with local observation and tests. It is found that the content of the oxygen reduce with the temperature increasing; however, gangue dump internal hydrogen content increase unusually on the rainfall conditions at 90°C, but the local measuring points reach the explosion limit. The existence of the CO and H2 is the main reason for inducing the explosion of spontaneous combustion coal gangue dump.

Experimental and calculated detonation characteristics of powerful insensitive explosives are given. Features of explosives with a high hydrogen content are discussed. The relationship between the power and sensitivity characteristics of explosives and the structure of their molecules are considered. Prospects for the development of powerful explosives are discussed.

To study the circumferential tensile properties of fuel claddings under a simulated high burn-up environment, ring tensile tests were carried out at both room temperature and 350 °C for Zr-Nb based fuel claddings such as Zr-Nb based HANA-6 (Zr-1.10Nb-0.05Cu), HANA-4 (Zr-1.50Nb-0.40Sn-0.20Fe-0.10Cr) and Zircaloy-4 (Zr-1.26Sn-0.23Fe-0.12Cr) cladding after they had been differently charged with hydrogen up to 2,850 ppm. The results showed that the HANA-6 cladding maintained more than a 20% circumferential elongation at room temperature without a decrease in its maximum strength when it was charged with hydrogen up to about 1,500 ppm, although the maximum circumferential strength and elongation of the Zircaloy-4 cladding decreased with increasing hydrogen content above 500 ppm. The circumferential elongation of the above claddings decreased as the hydrogen content increased at both room temperature and 350 °C but the strength increased a little with the hydrogen content at 350 °C. The maximum circumferential strength of the HANA-4 cladding also increased with the hydrogen content up to a level of 1,109 ppm, even at room temperature. It seemed that the Nb in the matrix contributed to better circumferential elongation and resistance to hydrogen embrittlement in the Zr-Nb based HANA-4 and HANA-6 claddings than was present in the Zircaloy-4 cladding.

An analysis is performed of the energy properties of solid high-energy systems containing ultrahigh-enthalpy polynitrogen compounds as the only component and in combination with other substances required to produce compositions with necessary operational characteristics. Special attention is given to the restriction of the combustion temperature by introducing substances with a high hydrogen content and a binder into the compositions. Such systems are compared with the best versions of real energetic compositions. As examples, calculations are given for compositions containing both hypothetical compounds (tetraazatetrahedrane N4, octaazacubane N8, trioxyhexazine N6O3, etc.) and real (derivatives of pyrroles, pyrazoles, triazoles, tetrazoles, and other polynitrogen high-enthalpy compounds).

The ultimate goal of the hydrogen economy is the development of hydrogen storage systems that meet or exceed the US DOE’s goals for onboard storage in hydrogen-powered vehicles. In order to develop new materials to meet these goals, it is extremely critical to accurately, uniformly and precisely measure materials’ properties relevant to the specific goals. Without this assurance, such measurements are not reliable and, therefore, do not provide a benefit toward the work at hand. In particular, capacity measurements for hydrogen storage materials must be based on valid and accurate results to ensure proper identification of promising materials for further development. Volumetric capacity determinations are becoming increasingly important for identifying promising materials, yet there exists controversy on how such determinations are made and whether such determinations are valid due to differing methodologies to count the hydrogen content. These issues are discussed herein, and we show mathematically that capacity determinations can be made rigorously and unambiguously if the constituent volumes are well defined and measurable in practice. It is widely accepted that this occurs for excess capacity determinations and we show here that this can happen for the total capacity determination. Because the adsorption volume is undefined, the absolute capacity determination remains imprecise. Furthermore, we show that there is a direct relationship between determining the respective capacities and the calibration constants used for the manometric and gravimetric techniques. Several suggested volumetric capacity figure-of-merits are defined, discussed and reporting requirements recommended. Finally, an example is provided to illustrate these protocols and concepts.

LiBH4 possesses a high hydrogen content, and though it is highly stable, its restoration from LiH+B+H2 can only be accomplished under unacceptable high temperature and pressure conditions (650 °C and 15 MPa). Recently, it has been reported that destabilizing LiBH4 by, i.e., MgH2, transition metal oxides and chlorides presents a promising approach to exert its potential for hydrogen storage. In the present study, we find that simple mechanical milling with Al in a mole ratio of 2:1, markedly improves the reversible dehydrogenation performance of LiBH4. The system possesses a theoretical capacity of 8.5 wt. % and could be reversibly operated at 400–450 °C. The combined property and phase examinations suggest that the observed property improvement should be associated with the formation of AlB2 in the dehydriding process. Further cyclic examination found that the system suffered from a serious capacity loss in the dehydriding/rehydriding cycles. A better understanding of the degradation mechanism may provide a means for further material property improvement.

Results are reported from the production of two trial heats of alloy steel in which the cast slabs were cooled in a thermostatted chamber and in a dense stack. It is shown that cooling slabs in such a chamber makes it possible to reduce the hydrogen content of the steel 30% compared to slabs that are cooled while stacked.

A new test method called “Bead Bend Test” for evaluation of the hydrogen-assisted cold cracking — (HAC) susceptibility of multi-layer welds will be presented. The main advantage of this test is the possibility of evaluation of weldments that are established by using real welding procedures. Also, different on-site stress conditions can be taken into account by variation of the clamping system. The test results can be used for theoretical investigations, but also for practical recommendations regarding the necessary minimum interpass temperatures to prevent HAC under consideration of the plate thickness, the materials strength level, and the diffusible hydrogen content of the weld metal. As an example, the HAC behaviour of high strength cellulosic pipeline weldments are discussed. An additional feature of this test procedure is the HAC evaluation of joints built up by a combination of different electrode types; e.g., cellulosic and basic types which are shown in a second example.

Current trends in the production of railroad wheels show the use of some promising techniques: a reduction in the carbon content of the finished steel; degassing the steel in a vacuum to decrease its hydrogen content; more efficient deoxidation and alloying of the steel. When used together, these measures are ensuring that the finished steel has the mechanical and service properties prescribed for wheel steel. Studies and factory testing of a new technology for making wheel steel have shown that the oxygen content of the steel can be reduced by its self-deoxidation during vacuum degassing. This approach also helps lower the steel’s hydrogen content while saving deoxidizers. Researchers have discovered certain laws that govern the relationship between the characteristics of wheel steel and its contents of sulfur and gases. The amount of sulfur and gases in this type of steel can be reduced by using efficient parameters for the treatment that is administered outside the steelmaking furnace.