Lithium-air battery attracts great attention because of its high energy density. However, due to the low solubility and diffusivity of oxygen in the electrolyte, oxygen transport to the reaction site of the positive electrode is limited. In this study, experiments using glassy carbon were conducted while changing the contact angle and contact area with the electrolyte in order to shorten the distance of oxygen transport to the electrolyte by thinning the electrolyte covering the reaction surface. As a result, when the electrolyte contact area changed, the thin electrolyte film was formed and the discharge performance was improved.

The effects of flow path structure of a redox flow battery on the discharge performance were investigated, and the cause of the performance difference were examined by measuring the current density distribution. It was confirmed from the current density distribution measurements that the current density decreases at down streams in the interdigitate designs, and that the current density distribution increases with lower SOC and higher average current density. It was confirmed that the effect of flow rate on the current density distribution was very small. This is presumably due to the fact that the average current density increases as the flow rate increases, which may counteract the improvement in performance that results from increasing the flow rate. I plan to measure the current density distribution by changing the electrolyte flow rate at the same average current density. The goal is to elucidate the relationship between the performance and the flow path structure by comparing the results with those of FTD.

A polymer electrolyte fuel cell (PEFC) attracts attention as the next generation of high efficiency energy conversion system due to their excellent starting performance and compact size. In the future, Fuel cell electric vehicles (FCEVs) are being deployed and developed for commercial vehicles, and further output improvement is required for further popularization. Meanwhile, as output increases, the amount of heat generated also increases, so the upper temperature limit of the PEFC must be improved to improve cooling efficiency. The recently developed high-temperature polymer electrolyte membrane fuel cell (HT-PEFC), which uses a high-temperature polymer electrolyte membrane (HT-PEM) that can be used non-humidified and high-temperature conditions, is being considered to solve the operating temperature conditions. While the HT-PEM can generate electricity at higher temperatures, the limiting current density values and power output are small compared to the power generation characteristics of the FCs currently installed in FCEVs. In this study, we evaluate the contribution to the polarization that is dominant in HT-PEFCs, especially the concentration polarization due to the decrease in oxygen concentration caused by high temperatures, by changing the operating conditions. In order to conduct the experiments, we fabricated a device for high-temperature power generation and selected a spring that can maintain a constant surface pressure in order to keep the experimental conditions constant. In addition, we operated the PEFC and evaluated its performance. As a result, generally normal performance was obtained, slightly inferior to the nominal performance of the HT-PEM, but comparable at high current densities.

Polymer electrolyte fuel cell (PEFC) are expected to be the next generation of high-efficiency energy conversion devices. In a PEFC, a thin film (several nm thick) of polymer electrolyte (typically Nafion) in the catalyst layer is responsible for transporting protons, while it also hinders oxygen transport. Therefore, the Nafion thin film is an important component to achieve high performance, but their structure and formation process are still not fully understood. In this study, we evaluate the structure and properties of Nafion using a surface plasmon resonance (SPR) imaging system. The results of the observation of pure water drops on the gold surface showed that the bright and dark areas between the gold-droplet interface region and the gold-atmosphere interface region were visible. Also, observation of the drying process of Nafion dispersion solution (film formation) showed that an agglomeration occurred. Then, a spin-coater deposition was applied as a uniform Nafion deposition method. In addition, as a preliminary step to observe the Nafion film when potential is applied during a power generation, the effect of potential application on the SPR observation was investigated.

In recent years, there has been a worldwide movement toward a decarbonized society in order to curb global warming. One of the ways to achieve a decarbonized society is to discontinue coal-fired power generation and shift to low-carbon energy sources. LNG, with its low CO2 emissions, has been attracting attention, and the demand for LNG has been increasing rapidly worldwide. Therefore, there is a growing need to store LNG of different densities in the same tank in order to increase the flexibility of LNG trading. However, when two or more types of LNG with different densities are stored in the same tank, stratification of the LNG occurs and a rollover phenomenon takes place. This can lead to excessive evaporation gas (BOG =Boil Off Gas), which can lead to LNG leakage and tank damage. Therefore, the final objective of this study is to establish an analysis technique that can predict and realize the rollover phenomenon. In order to improve the accuracy of the numerical analysis, a solid-liquid coupling was taken into account in the analysis. In addition, in order to compare the results of numerical analysis with experimental results, it is necessary to devise an experimental method to measure the amount of phase change and to conduct experiments.

Melting convection is a factor that greatly affects the progress of actual melting heat storage, as well as the thermal conductivity of the heat storage material. Generating convection in the molten region of the latent heat storage material significantly reduces the latent heat storage time. However, in latent heat storage, where the phase change from solid to liquid progresses, it is difficult to adopt a mechanical stirring method. Therefore, the heat exchange method adopted in this study is heat transfer in which high-temperature air jets impinge on the latent heat storage material. Therefore, it is possible to generate forced convection in the molten liquid phase during latent heat storage. This paper describes the results of an experimental investigation of the impinging jet melting process of paraffin-based latent heat storage materials.

The proposed system in this study is comprised of a single solid oxide fuel cell (SOFC) unit, Gas Steam Turbine Combined Cycle, and a proton exchange membrane electrolyzer (PEMEC) for hydrogen production equipped with a hydrogen storage system. The system is connected to renewable energy sources, and in this study, is purposed for hydrogen production in the case of extra power. The SOFC is operated in a governor-free mode to adjust output according to the load pattern. The combined cycle power plant is designed to perform combustion on hydrogen fuel and SOFC exhaust heat. The hydrogen fuel is supplied by PEMEC through a hydrogen tank. Study shows that with one unit of SOFC, the power generated is quite responsive to the load demand pattern provided thus providing a power stabilization effect to the system. For a more robust response, it is suggested to increase the amount of SOFC units in the system.

Ti alloys are metallic materials with excellent properties such as high specific strength and corrosion resistance. However, the deformation mechanism is extremely complex, and there are many unresolved points concerning the microscopic deformation mechanism. In this study, crystal plasticity analysis was performed to investigate the redistribution mechanism of stress and strain between regions with deformation. The results showed that, in the early stage of deformation, slip began in areas where the Schmid factor was high, and the high strain regions were discontinuous at this stage. However, in the later stage of deformation, strain increased even in areas where the Schmid factor was not high, leading to formation of band-like high strain regions (HSBs). The cause of this was the development of multiaxial stresses with deformation, and in addition to normal stress in the tensile direction, other stress components had a significant effect on the formation of HSBs.

Critical resolved shear stress (CRSS) determines the ease of slip deformation of metals and the values are different among slip systems. The CRSS ratio among slip systems is an important factor governing the plastic deformation mechanism. Thus, estimation methods for easily evaluating the CRSS ratio will play an important role to understand the deformation mechanisms. While our laboratory has developed a prediction system for CRSS ratios, it has not been sufficiently verified. In this study, the accuracy of the CRSS ratio prediction system was verified using sets of crystal orientations, CRSS ratios, and strain distributions estimated by crystal plasticity analysis. The results showed that when two or more slip systems were active, the CRSS ratios were successfully predicted. However, we found that prediction accuracy decreased under the following three conditions: only one slip system was dominantly active, multiple slip systems were active in the same area, and the distributions of the Schmid factors were similar among the slip systems. Methods to improve the accuracy of their predictions were also discussed.

This study analyzes the environmental performance (fuel consumption rate) based on the Worldwide Harmonized Light Vehicle Test Cycles (WLTC) mode when a conventional internal combustion motor ICEV is used as an FCV by simulation, considering the maximum vehicle speed and one fill trip distance. The relationship between the application, body type, and fuel consumption rate is discussed. The analysis showed that the higher the energy consumed by the vehicle in each driving mode, the lower the combustion consumption rate tends to be, but the difference between different vehicle types and body types decreases as the driving speed increases, such as highway driving. Therefore, the effects of vehicle weight, vehicle type, and body type on fuel consumption rate may be less of an issue when FCVs are used for inter-city travel than when driving in the suburbs. In addition, the fuel consumption rate of FCVs was found to decrease as the driving speed increases. Therefore, considering environmental performance, unlike gasoline vehicles, FCVs should be driven at lower speeds.

In order to achieve carbon neutrality by 2050, it will be necessary to introduce renewable energy for electricity and heat supply. Therefore, this study examines the possibility of supplying energy to Hakodate City from a 722 MW rated offshore wind power generation system planned off the coast of Hiyama in southern Hokkaido. In the proposed system, power from the offshore and onshore wind turbines will be transmitted to a substation near Hakodate City via a transmission line. Substations A, B, and C have different storage methods: substation A uses hydrogen and storage batteries; substation B uses only hydrogen; and substation C uses only storage batteries. These stored hydrogen and electricity will be transmitted to Hakodate City in the event of supply shortages. The analysis results show that the introduction cost is approximately 830 billion yen lower when electricity stored in storage batteries is used preferentially, compared to the case where hydrogen is used preferentially. Therefore, we believe that using electricity stored in storage batteries as a priority, reducing the storage battery capacity and increasing the hydrogen tank capacity, will result in a system with lower installation costs and a higher supply ratio.

In order to achieve zero carbon dioxide emissions by 2050, there is an urgent need to shift from fossil fuel-based power generation to renewable energy-based power generation. We believe that regional microgrids require new substations that can smoothly introduce renewable energy, disconnect from the power grid in the event of a disaster, and maintain local power transmission. Therefore, this study plans a power distribution system for local production and local consumption of energy using a regional microgrid. This study will require a large power supply system. Therefore, we will construct a microgrid using large-scale photovoltaic power generation as the power source, which can be introduced regardless of the region. In addition, since photovoltaic power generation is subject to large fluctuations, a large-scale storage battery is necessary. Therefore, this research aims to reduce costs by using EV car batteries as a substitute for large-scale storage batteries. Large-scale photovoltaic power generation is expected to experience large fluctuations in power generation. Therefore, in this project, power plants will be distributed throughout the region to level out the amount of electricity generated. Furthermore, the economic feasibility of the project will be evaluated using the DCF method, which allows future cash flows to be calculated taking into account the discount rate, making it possible to evaluate the feasibility of corporate investment as a guideline..

CO₂ hydrates is a promising storage method for high-density, high-pressure CO₂ gas because it is formed at around 0°C and dissociates at 10-20°C under high pressure of several MPa. As a way to increase the storage efficiency of the proposed CO₂ hydrate storage system, if the temperature conditions during CO₂ hydrates generation can be shifted to the room temperature side, more CO₂ hydrates can be generated with less cold heat, and energy-efficient high-pressure CO₂ gas storage will become possible. In this study, we report the results of a CO₂ hydrates generation experiment in which the generation temperature was shifted to the room temperature side when cyclopentane was added.

This study investigates the costs and revenues of an integrated SOFC power generation system with a CO₂ used system during design, construction and operation to determine the economic feasibility of the system in actual operation. The focus of the entire system is to use the carbon dioxide captured by the system to synthesize methanol and methane, and to improve the economics of the system by selling methanol and electricity while obtaining high power generation efficiency. In this study, the discounted cash flow method was used to evaluate the economic performance of the proposed system considering that the system can provide stable cash income. With a unit sales price of 0.36USD/kWh, the proposed system has a simple combined equilibrium payback period of 9 years, a NPV (Net present value) of 10 years, and a DBPD (Dynamic payback period) of 18.89 years. It was determined that the constructed system is economical in actual operation.

To study the airflow control effect of a plasma actuator (PA) on a simulated airfoil (equipped with a passive control wing on the upper edge of a photovoltaic cell), particle image velocimetry (PIV) measurements were carried out in the outdoors. A plasma electrode developed by Asahi Rubber Inc. is installed at the rear end of the passive control wing. As tracers for PIV measurement, we used soap bubbles generated from two types of supply devices (a coaxial triple tube nozzle generator and a rotating cylindrical generator). The former can generate microbubbles with a diameter of about 0.9 mm, and the latter can generate many bubbles with a diameter of about 5 mm. Under the PA_OFF condition, the wind speed measured by the propeller anemometer and the average wind speed measured by the PIV showed good agreement. It was confirmed that outdoor PIV measurement is possible by using soap bubbles as a tracer. We also confirmed the airflow control effect of the plasma actuator in the field.

The flow around the automobile tire house was investigated from numerical analysis, and the effective location of PAs, which can be expected to provide snow protection, was studied from numerical analysis. First, the effect of the ground on the experimental conditions was investigated for the tire house model currently being tested. Next, the location of PA installation was investigated by reproducing the PA effect using a surface velocity model. When the PA was installed behind the tire and driven steadily, the results showed that the flow behind the tire increased in speed, and it was inferred that the PA drive could be expected to provide snow protection.

A special wind tunnel test apparatus is being developed to evaluate the weather resistance of erosion sheets for wind turbines in snowy and cold regions. Mechanisms for feeding sand and snow as erosion sources were investigated; the first is a slope-type feeding device. This device was fabricated with a thermal-melt 3D printer for use with sand grains, but the slope angle was too small to allow the sand grains to stagnate. The second is a brush-type feeding device for snowflakes. Two opposing brushes are rotated in opposite directions to entrain snowflakes. It was found that snowflakes are ejected from the feeder immediately after rotation, but after operation, snowflakes adhere to the brush surface. We plan to improve both feeders and verify their durability against erosion sheets.

The ventilation behavior of a natural convection ventilation system with an external flow that ventilates the room by the ventilation effect of natural wind and the circulation action of the natural convection of the heat source was investigated by unsteady CFD analysis. The buoyantPimpleFoam of blueCFD-Core 2020 was used in combination with the scalar mass transport equation. The analysis target was a room of 4m (length) x 3m (width) x 2.5m (height), and two ventilation holes with a diameter of 150mm were provided at both the inflow and outflow. As a result of investigating the diffusive advection of the scalar amount under the condition of the outside air wind speed of 2m/s, it was confirmed that the scalar amount was diffusively ventilated more than 90% within 50 minutes. It was reconfirmed that this system, which uses wind as a driving source and body temperature as a stirring energy source, is very useful from the viewpoint of energy saving.

Japan's infrastructure facilities are faced with a huge inspection area and a shortage of inspection personnel. Therefore, efficient inspection is required, and the development of robots that can inspect pipes and wall surfaces is needed. However, most of these robots are designed for a single environment, and there has been no progress in the development of robots that can handle multiple environments. In this report, we focus on the development of a leg mechanism equipped with a detachable suction mechanism that can move not only on a flat surface but also on pipes and walls. We also fabricated a robot equipped with the leg mechanism, conducted walking experiments in various environments, and confirmed the usefulness of the leg mechanism based on the experimental results.

We have examined a pipe traveling robot using microwave guided-modes propagating along PVC pipe-wall. It was confirmed that the effect of the guide that restricted the flexibility with the spring which produced a pipe traveling robot.

In recent years，accidents such as road subsidence have occurred due to the breakage of water pipes caused by aging. In order to prevent such accidents，ground-penetrating radar surveys are used to investigate water pipes. In order to reduce the burden of this survey，a cart equipped with an omni-directional moving mechanism is being considered. However，the omni-directional moving mechanism is vulnerable to bumps and slopes，which poses a problem when operated outdoors. Therefore，this study aims to reduce the burden on the operator by applying a power assist to the omni-directional moving mechanism. For this purpose，a cart equipped with an omni-directional moving mechanism w that can run outdoors was fabricated，equipment for power assist was selected，and a power assist control method was studied and implemented. We also conducted running experiments using the implemented power assist system and measured the data. As a result，it was found that power assist is possible for the omni-directional moving mechanism. One of the issues was the large difference from the target value of the assist due to insufficient motor torque．

The Center for Winter Sports Science at the Kitami Institute of Technology has a "SkyTech" ski simulator. In the experiment, the pressure sensor "Pedar" installed on the sole of the ski boot and the "internal inclination angle measurement device" attached to "SkyTech" were used to measure the plantar pressure and internal inclination angle during the turning motion. In this study, we first conducted a questionnaire survey on the players' perceived strengths and weaknesses of left-right turns. Then, we calculated various parameters to numerically evaluate left-right turn movements from the data obtained from the plantar pressure sensor and the internal inclination angle measurement device in an experiment using the "SkyTech" ski simulator, and examined the indexes of the obtained parameters and the players' turn awareness. The results of the experiment tended to be close to the results of the questionnaire. We believe that a clear trend will become apparent when the number of subjects and experiments are increased in the future.

Research Center for Winter Sports Science of Kitami Institute of Technology was established in 2016. Curling and alpine skiing are researched at this center located in a snowy and heavy cold area. The center has been promoting the design and development of a ski boots that will improve the Japanese skiers’ speed in alpine ski competitions. Previous experimental studies have shown that attaching parts to the underside of the footbed inside the ski boot changes the inclination angle and inclination angular velocity. In this study, we used the ski simulator "SkyTech" at this center and "the real-time experimental data collection system" with a pressure sensor and the inclination angle measuring devices, and performed an experiment to adjustment of optimal depression angle. As a result, the evaluation parameters were improved by changing the angle of elevation of the subject's footbed. Research Center for Winter Sports Science of Kitami Institute of Technology can numerically adjust each athlete's ski boots optimally.

When preparing the manuscript, read and observe carefully this sample as well as the instruction manual for the manuscript of the Transaction of Japan Society of Mechanical Engineers. This sample was prepared using MS-word. We are conducting experiments and measurements using the “Sky Tech” ski simulator at Research Center for Winter Sports Science of Kitami Institute of Technology. Previous experimental studies have shown that skiers with high skill levels who reach the goal in a short downhill time have a large maximum inclination angle during turns. From this, it became clear that the large inclination angle and a fast inclination angular velocity during turns have a great influence on the improvement of downhill speed in alpine skiing^{(1) ~ (6)}. In addition, it was found that the slight deformation of the footbed, which is a part inserted in the ski boots, is involved in the increasing the inclination angle. In this study, we performance an experiment using the“SkyTech”ski simulator that was varied the angle of depression on the footbed.