Japan
Fabrication of CdS/β-SiC/TiO2 Tri-composites That Exploit Hole- and Electron-transfer Processes for Photocatalytic Hydrogen Production Under Visible Light
Dec 2017
Publication
In this work CdS/SiC/TiO2 tri-composite photocatalysts that exploit electron- and hole-transfer processes were fabricated using an easy two-step method in the liquid phase. The photocatalyst with a 1:1:1 M ratio of CdS/SiC/TiO2 exhibited a rate of hydrogen evolution from an aqueous solution of sodium sulfite and sodium sulfide under visible light of 137 μmol h−1 g−1 which is 9.5 times that of pure CdS. β-SiC can act as a sink for the photogenerated holes b Read More
Numerical investigation of hydrogen leakage from a high pressure tank and pipeline
Sep 2017
Publication
We numerically investigated high-pressure hydrogen leakage from facilities in storage and transportation phases. In storage phase assuming a tank placed in a hydrogen station we examined unsteady diffusion distance up to 100 ms after leakage. A series of simulations led us to develop an equation of unsteady hydrogen diffusion distance as a function of mass flow rate leakage opening diameter and tank pressure. These results helped us develop a safety Read More
Numerical Investigation of Hydrogen Leakage from a High Pressure Tank and its Explosion
Oct 2015
Publication
We numerically investigated the initial behaviour of leakage and diffusion from high-pressure hydrogen storage tank assumed in hydrogen station. First calculations are carried out to validate the present numerical approach and compare with the theoretical distribution of hydrogen mass fraction to the direction which is vertical to the jet direction in the case of hydrogen leaking out from the circular injection port whose diameter is 0.25 mm. Then Read More
The Spread of Fire from Adjoining Vehicles to a Hydrogen Fuel Cell Vehicle
Sep 2011
Publication
Two vehicle fire tests were conducted to investigate the spread of fire to adjacent vehicles from a hydrogen fuel cell vehicle (HFCV) equipped with a thermal pressure relief device (TPRD) : – 1) an HFCV fire test involving an adjacent gasoline vehicle 2) a fire test involving three adjoining HFCV assuming their transportation in a carrier ship. The test results indicated that the adjacent vehicles were ignited by flames from the interior and exterior material Read More
A Panoramic Analysis of Hydrogen Utilization Systems Using an Input-output Table for Next Generation Energy Systems
Apr 2017
Publication
The objective of this study is to analyze a government proposal from a panoramic perspective concerning the economic and environmental effects associated with the construction and operation of hydrogen utilization systems by the year 2030. We focused on a marine transport system for hydrogen produced offshore hydrogen gas turbine power generation fuel cell vehicles (FCVs) and hydrogen stations as well as residential fuel cell systems ( Read More
A Study on the Effectivity of Hydrogen Leakage Detection for Hydrogen Fuel Cell
Sep 2017
Publication
Unlike four-wheel fuel-cell vehicles fuel-cell motorcycles have little semi-closure space corresponding to the engine compartment of four-wheel fuel-cell vehicles. Furthermore motorcycles may fall while parked or running. We conducted hydrogen concentration measurement and ignition tests to evaluate the feasibility of detecting leaks when hydrogen gas leaked from a fuel-cell motorcycle as well as the risk of ignition. We found that the installation of Read More
Localized Plasticity and Associated Cracking in Stable and Metastable High-Entropy Alloys Pre-Charged with Hydrogen
Dec 2018
Publication
We investigated hydrogen embrittlement in Fe20Mn20Ni20Cr20Co and Fe30Mn10Cr10Co (at.%) alloys pre-charged with 100 MPa hydrogen gas by tensile testing at three initial strain rates of 10−4 10−3 and 10−2 s−1 at ambient temperature. The alloys are classified as stable and metastable austenite-based high-entropy alloys (HEAs) respectively. Both HEAs showed the characteristic hydrogen-induced degradation of tensile ductility. Electron backscatt Read More
Prediction of Pressure Reduction Rate in 30 m3 Liquid Hydrogen Tank Based on Experimental and Numerical Analysis
Sep 2019
Publication
Liquid hydrogen (LH2) compared to compressed gaseous hydrogen offers advantages for large scale transport and storage of hydrogen with higher densities and potentially better safety performance. Although the gas industry has good experience with LH2 only little experience is available for the new applications of LH2 as an energy carrier. Therefore the European FCH JU funded project PRESLHY conducts pre-normative research for the safe use of cryoge Read More
Non-steady Characteristics of Dispersion and Ignitability for High-pressurized Hydrogen Jet Discharged From a Pinhole
Sep 2017
Publication
Hydrogen gas concentrations and jet velocities were measured downstream by a high response speed flame ionization detector and PIV (Particle Image Velocimetry) in order to investigate the characteristics of dispersion and ignitability for 40–82 MPa high-pressurized hydrogen jet discharged from a nozzle with 0.2 mm diameter. The light emitted from both OH radical and water vapor species yielded from hydrogen combustion ignited by an electric s Read More
Reversible Ammonia-based and Liquid Organic Hydrogen Carriers for High-density Hydrogen Storage: Recent Progress
Feb 2019
Publication
Liquid hydrogen carriers are considered to be attractive hydrogen storage options because of their ease of integration into existing chemical transportation infrastructures when compared with liquid or compressed hydrogen. The development of such carriers forms part of the work of the International Energy Agency Task 32: Hydrogen-Based Energy Storage. Here we report the state-of-the-art for ammonia-based and liquid organic hydrogen carriers wit Read More
Performance Tests of Catalysts for the Safe Conversion of Hydrogen Inside the Nuclear Waste Containers in Fukushima Daiichi
Sep 2019
Publication
The safe decommissioning as well as decontamination of the radioactive waste resulting from the nuclear accident in Fukushima Daiichi represents a huge task for the next decade. At present research and development on long-term safe storage containers has become an urgent task with international cooperation in Japan. One challenge is the generation of hydrogen and oxygen in significant amounts by means of radiolysis inside the containers Read More
Cost Optimization of a Stand-Alone Hybrid Energy System with Fuel Cell and PV
Mar 2020
Publication
Renewable energy has become very popular in recent years. The amount of renewable generation has increased in both grid-connected and stand-alone systems. This is because it can provide clean energy in a cost-effective and environmentally friendly fashion. Among all varieties photovoltaic (PV) is the ultimate rising star. Integration of other technologies with solar is enhancing the efficiency and reliability of the system. In this paper a fuel cell–sol Read More
A Production and Delivery Model of Hydrogen from Solar Thermal Energy in the United Arab Emirates
May 2022
Publication
Hydrogen production from surplus solar electricity as energy storage for export purposes can push towards large-scale application of solar energy in the United Arab Emirates and the Middle East region; this region’s properties of high solar irradiance and vast empty lands provide a good fit for solar technologies such as concentrated solar power and photovoltaics. However a thorough comparison between the two solar technologies as well as Read More
Comparative Technical and Economic Analyses of Hydrogen-Based Steel and Power Sectors
Mar 2024
Publication
Decarbonizing the current steel and power sectors through the development of the hydrogen direct-reduction iron ore–electric arc furnace route and the 100% hydrogen-fired gas turbine cycle is crucial. The current study focuses on three clusters of research works. The first cluster covers the investigation of the mass and energy balance of the route and the subsequent application of these values in experiments to optimize the reduction yield of iron or Read More
Alloy Optimization for Reducing Delayed Fracture Sensitivity of 2000 MPa Press Hardening Steel
Jun 2020
Publication
Press hardening steel (PHS) is widely applied in current automotive body design. The trend of using PHS grades with strengths above 1500 MPa raises concerns about sensitivity to hydrogen embrittlement. This study investigates the hydrogen delayed fracture sensitivity of steel alloy 32MnB5 with a 2000 MPa tensile strength and that of several alloy variants involving molybdenum and niobium. It is shown that the delayed cracking resistance can be larg Read More
Crack Size Dependency of Shear-mode Fatigue Threshold in Bearing Steel Subjected to Continuous Hydrogen Charging
Jun 2019
Publication
Premature delamination failure characterized by the white structure flaking (WSF) or the white etching crack (WEC) often occurs in rolling element bearings and it deteriorates the durability of bearing substantially. It is known that this failure is caused by shear-mode (Mode II and Mode III) crack growth in conjunction with evolution and invasion of hydrogen into material during operation. To ensure the structural integrity associated with rolling eleme Read More
Effect of Defects and Hydrogen on the Fatigue Limit of Ni-based Superalloy 718
Dec 2019
Publication
Tension-compression fatigue tests were performed on two types of Ni-based superalloy 718 with different microstructures to which small artificial defects of various shapes and sizes were introduced. Similar tests were also conducted on hydrogen-charged specimens with defects with a solute hydrogen content ranging from 26.3 to 91.0 mass ppm. In the non-charged specimens in particular the fatigue strength susceptibility to defects varied significantly a Read More
Removing the Bottleneck on Wind Power Potential to Create Liquid Fuels from Locally Available Biomass
Jun 2021
Publication
In order to reduce global greenhouse gas emissions renewable energy technologies such as wind power and solar photovoltaic power systems have recently become more widespread. However Japan as a nation faces high reliance on imported fossil fuels for electricity generation despite having great potential for further renewable energy development. The focus of this study examines untapped geographical locations in Japan’s northern most prefecture Ho Read More
Effects of Thermomechanical Processing on Hydrogen Embrittlement Properties of Ultrahigh-Strength TRIP-Aided Bainitic Ferrite Steels
Jan 2022
Publication
The effects of thermomechanical processing on the microstructure and hydrogen embrittlement properties of ultrahigh-strength low-alloy transformation-induced plasticity (TRIP)-aided bainitic ferrite (TBF) steels were investigated to apply to automobile forging parts such as engine and drivetrain parts. The hydrogen embrittlement properties were evaluated by conducting conventional tensile tests after hydrogen charging and constant load four-point Read More
Effects of Hydrogen Pressure, Test Frequency and Test Temperature on Fatigue Crack Growth Properties of Low-carbon Steel in Gaseous Hydrogen
Jul 2016
Publication
Fatigue crack growth (FCG) tests for compact tension (CT) specimens of an annealed low-carbon steel JIS-SM490B were performed under various combinations of hydrogen pressures ranging from 0.1 to 90 MPa test frequencies from 0.001 to 10 Hz and test temperatures of room temperature (RT) 363 K and 423 K. In the hydrogen pressures of 0.1 0.7 and 10 MPa at RT the FCG rate increased with a decrease in the test frequency; then peaked out. I Read More
No more items...