URAWA hydrogen refueling station is as on-site station which products and supplies hydrogen locally, and it is the main station for shipping hydrogen among TOKYO GAS's stations. Hydrogen which is produced at URAWA hydrogen refueling station is used for filling Fuel Cell Vehicles (FCVs), and is shipped to neighboring off-site stations such as NERIMA(tokyo) hydrogen refueling station. As it produces hydrogen by reforming city gas pipeline network, carrying hydrogen is not needed and stable supply can be performed. URAWA hydrogen refueling station is associated to a natural gas station. The station incurs operates more efficiently by sharing some of its equipment with the compressed natural gas station.
The Low temperature differential Stirling engine for a craft workshop was improved. Fine adjustment during assembly is not necessary. In addition, the seal of a displacer rod does not require a grease. Here, the explanation for attendees of a 5-hour-course craft workshop is shown by some pictures.
A Stirling engine operates with temperature difference between a hot and a cold space in the engine. Then the engine is focused as one of the energy saving or environmental technologies, because it can use various heat energy such as biomass fuel, solar energy and exhaust gas of an internal combustion engine. On the other hand, as the Stirling engine has simple structure, one can build a model engine with a little effort. In this paper, characteristics of the model and practical used Stirling engines are discussed. Also the author shows a development example of a Stirling engine generator using waste heat as the heat source.
Drones are expected to revolutionize transportation of goods to geographically isolated areas, especially in natural disasters, such as typhoons or earthquakes. In designing safety measures for drones, designers should evaluate risks of accidents, and determine the level of risk that the society would regard as acceptable. However, it is often difficult to predict how the society would react to an accident. A mock trial may provide guidance for designers because mock trail judges, who are experienced lawyers, could reflect general expectation of the society for safety of new technologies.
In this research, the objective is to reveal the alliance system suitable for products and technologies by extracting and associating the alliance characteristics and the dynamics in the joint development of multiplex products / technologies called the science-type industry in our country. Author's first motivation to this research is to focus on the tips that the product development process of any organizations which may be normally unknown might be able to subject to close analysis based on external public information such as patents and articles, and the second motivation is to focus on the idea that it may be possible to read the characteristics for achieving the objective carefully from the alliance system in cooperative development between different business fields, which is different from the original development carried out by the traditional single organization as well as the joint development inside the same business area. Quantitative expressions of hypotheses (hypothesis construction) are performed by adopting the qualitative expression of hypotheses based on these motivations.
After the Great East Japan Earthquake in 2011, imported fossil fuels, energy cost and greenhouse gas are increasing and then the energy self-sufficiency rate is declining. The government is now promoting the effective use of renewable energy. Since the small hydropower is a clean domestic origin energy resources, it is expected to spread as a stable base load power generation. In this paper, the concrete cases of micro hydropower generation system by using Pump as Turbine, having the advantages for less investment and easier maintenance, applied in irrigation dam and water works, are introduced.
The transonic buffet degrades the aerodynamic performance of the aircraft during cruise. It is a phenomenon that should be avoided absolutely as it may lead to accidents. However, the mechanism of occurrence has yet to be elucidated. To understand this phenomenon, large-scale unsteady data is accumulated using computational fluid dynamics. In contrast, data mining of time series data such as unsteady data is a topic of the future in that field. In this study, we attempted mining unsteady data with capacity exceeding Tera’s order. As a result, the behavior of the physical quantity is suggested to be different from the data just before the transonic buffet occurs. Based on this result, we visualized the data over time, and found that the characteristic change of the viscosity distribution of the wing surface can be seen. This should be a clue to elucidate this phenomenon.
The utilization of measurement data is becoming attractive in various fields due to the massive growth of sensing and networking technologies boosted by, so-called, the internet of things (IoT). It is expected to utilize such a data-rich environment to improve engineering simulations in computer-aided engineering (CAE). Data assimilation is one of the methodologies to statistically integrate a numerical model and measurement data, and it would be a key technology to take advantage of IoT technologies in CAE. Unlike meteorological data assimilation where the estimation of initial conditions for numerical weather prediction is of primary interest, engineering data assimilation, as it is called, data assimilation-aided engineering (DAE), should focus on other functionalities of data assimilation such as the improvement of a model by parameter estimation and adaptive measurement based on model prediction. In this article, we describe examples of such data assimilation studies applied to engineering problems.
Safety in design, manufacturing and service stages of machines is basically examined by safety factor in the mechanical fields. The safety factors are shown on the standard or codes which usually mean the safety margin against uncertainty such as variability of strength. Typically, allowable stress value is defined by fundamental material strength divided by safety factor. This fundamental concept for safety examination is widely applied for all states of design, manufacturing and service in mechanical fields. This approach is quite simple both for regulator and for designer and has been used for the long time. Recently, drawback of this method is pointed out in order to apply risk management for mechanical structures and the introduction of reliability based design is widely desired. In this forum, application of reliability based design to many industrial fields will be introduced.
In response to the increasing demands for the reliability assessment of mechanical structures, a new standard is being issued from the Japan Society of Mechanical Engineers that provides procedures applicable to mechanical products in general utilizing the Load and Resistance Factor Design (LRFD) method. This standard complies to the requirements of the newly published Japanese Industrial Standard “JIS B 9955:2017 General principles on reliability for mechanical products”, which gives the principles of reliability evaluation of mechanical products. This paper describes the background and technical features of the standard as well as some of the activities on developing related codes and standards.
Japanese mandatory structural design regulations for fixed and mobile cranes are based on the allowable stress design approach. However, ISO8686, the international standard concerning the loads and load combinations for cranes, provides an option to adopt the limit state design approach instead of the allowable stress design approach. This paper describes an outline of the limit state design method stated in ISO8686-1 and ISO8686-2.
This study presents an approach to a rational integrity evaluation method of rules on fitness-for-service based on the quantitative margin evaluation. So-called twice-slope method is being applied with design margin in fitness-for-service code as one of the limit analyses to evaluate collapse or plastic buckling, to reactor internals such as core shroud even when it has cracks. Monotonic and cyclic loading test using cylindrical test specimens simulating core shroud showed conservatism of conventional design margin. In order to evaluate an appropriate design margin quantitatively, potential factors which may have effect on collapse load were identified and the probabilistic distribution of collapse load caused by the variation of these factors was calculated.
Fitness-For-Service (FFS) assessment for the component with metal-loss is desired to reflect the effect of usual maintenance. Introduction of evaluation method based on reliability is one of the effective measures to achieve this. High Pressure Institute of Japan published HPIS Z 109TR:2016 “Metal loss assessment for pressure equipment based on reliability”, which provides methods and technical backgrounds of metal loss assessment for pressure equipment based on reliability. This technical report provides evaluation method for simply evaluating reliability of the pressure equipment with metal loss based on the partial safety factor method. We present outline of the evaluation method based on the partial safety factor method.
Recent additive manufacturing technologies can be used to fabricate porous metals with precise internal pore structures and effective performance. We use topology optimization to derive an optimal microstructure shape with high stiffness that is verified experimentally. The design maximizes the effective bulk modulus and isotropic stiffness, and the performance is compared with Hashin-Shtrikman (HS) bounds. The optimized structure is fabricated via selective laser melting of maraging steel, which is a high-strength, iron-nickel steel that cannot easily be made porous with conventional methods. The optimal porous structure achieved 85% of the performance of the HS upper bound in numerical simulations, and at least 90% of them were realized in compressive testing.
In this study, the selective metal melting technology was used for manufacturing the micro-lattice structure, and the effects of laser condition (laser power, scanning speed) on the mechanical properties of lattice block were investigated. Also, by using X-ray CT, the ratio of microstructural void in the lattice was observed. When the laser power increases, the average strand's diameter increases almost linearly. On the contrary, the diameter has a minimum value as the scanning speed increases. Also, the stress-strain curve of lattice block is sensitive to the laser conditions, which is mainly caused by the change of strand's diameter.
The metal powders suitable for the additive manufacturing have four properties high purity, flowability, high bulk density and correct particle size distribution. The shapes of metal powders used for the metal additive manufacturing are spherical in order to achieve uniform thickness and high bulk density of powder layers in powder-bed-based processes. In order to control the powder shape spherically, various atomization, classification and surface modification processes have been developed. For the advances in metal additive manufacturing technology, the characteristics of the metal powders that affect process stability and the quality of build parts are investigated and controlled.
In this study, our objective was to describe a technique for the conservation of national treasures. Hanging scrolls are one of the national treasures of Japan. Hanging scrolls are a type of traditional Japanese ornamental art and include paintings and calligraphy. The conservation of hanging scrolls can be categorized into 10 processes. In this report, the effectiveness of the beating technique in the subsidiary lining process has been described. The beating procedures employed by an expert and non-expert were analyzed using a 3D motion capture system. The expert had a shorter working time and fewer numbers of beatings. The expert used both hands alternately to hasten the beating and the range of the beating position was wider than the actual paper, suggesting that the load was evenly loaded when finished.
A highly reliable joint structure, composed of a “nano-spring” layer, for a power-semiconductor device was developed. The nano-spring layer is a structure composed of multiple nanoscale springs made by the glancing angle deposition method. In the case of the developed structure, the die has a nano-spring layer on its surface and that layer is bonded to a metallic circuit by soldering. Thermal stress in the structure is reduced because the nano-spring layer absorbs the difference between the thermal deformations of the die and the metallic circuit.
Aircraft fuel expense accounts for a high proportion of total operating expense. Accordingly, reduction of aircraft drag affects directly airline’s operation. Moreover, stringent numerical targets for reduction of noise, CO2 and NOx emission were set by ICAO. To this end one of the technologies to enhance such environmental performances a morphing technology in which wing configuration varies seamlessly without gaps and kinks. In this paper R&D activities on the morphing technology in Japan are introduced and challenges to be solved and strategy aimed at proposal on collaborative projects are discussed.
Recently, degradation of the aged infrastructures is becoming serious problem in Japan. Because of the economic reason, method of preserving based on economic rationality is important. Risk based method is one of the statistical rationalization method. Risk based rationalization method for inspection/maintenance is called as Risk Based Inspection(RBI)/Risk Based Maintenance(RBM). In this paper, introduction for the RBM and the method for risk evaluation from smart structure are explained.
Recently a mobility system been changed dramatically in many aspects, such as the improvements of energy efficiency of prime mover, self-driving technology and security-related technology. In this paper the environmental burden of mobility system is picked up and discussed briefly from the viewpoint of LCA(Life Cycle Assessment).
The next-generation vehicles which include the Electric Vehicles and Hybrid Electric Vehicles (HEV) are researched and expected to reduce CO2 emissions in the future. To evaluate the emission and fuel economy for the next-generation HEVs, the high accuracy certification test method is necessary. Therefore, new HILS (Hardware-In- the-Loop-Simulator) test method was produced. The new HILS system, which called the extended-HILS, was consisted of the real engine and the HILS, which was modeled by the virtual drive train and vehicle. In this report, the evaluation for the next-generation HEVs (for example, Plug-in HEV, HEV with the electrically heating catalyst) was introduced.
The three great inventions were done in Japan. These were, Nd-Fe magnet for a motor, Li-ion battery and GaN transistor for an inverter. These technologies are matured to be used for electric vehicles, to realize high performance, comfortable and low cost electric vehicles. The way to use these technology is another importance. In-wheel motor including inverter and a new concept Li-ion battery are indispensable for wide spread of electric vehicles. 700km range per charge with 35kWh battery, wide space in the cabin and high drive performance will be possible by adopting all the technology.
Pipe wall thinning is an important issue for aging management of nuclear and fossil power plants. The Japan Society of Mechanical Engineers (JSME) published a guideline on pipe wall thinning management in 2005 and management codes in 2006, which is based on inspection using UT. In JSME, research committee for the improvement of pipe wall thinning management has been held since 2008, where state of the arts technical knowledge was investigated. In this committee, research for new technical knowledge for the mechanisms of wall thinning, evaluation methods, new inspection methods etc. Regarding the evaluation methods, how it is reflected to the management codes is considered. Risk based management and criteria for local wall thinning are also investigated.
Pipe wall thinning is an important issue for aging management of nuclear and fossil power plants. The Japanese Society of Mechanical Engineers (JSME) published a guideline on pipe wall thinning management in 2005 and since then, thinning of pipe wall thickness has been managed based on non-destructive inspection of pipe wall thickness. In JSME, research committee for the improvement of pipe wall thinning management has been established in 2008. In this committee, surveillance studies have been conducted on concerned technical area including wall thinning prediction and inspection method to revise a technical knowledge report attached to the JSME guideline. This paper summarizes recent advances of technical knowledge regarding flow accelerated corrosion and liquid drop impingement.
In the wall thinning management based on "Rules on Pipe Wall Thinning Management for PWR Power Plants", the period to reach the thickness shell requirement is evaluated by using the thinning rate based on the pipe wall thickness measurement result. In order to realize the safe and reasonable piping thinning management, developments of more advanced inspection technology are required. Furthermore, in overseas nuclear power plant, piping materials compositions are measured in in-service or Pre-service. More optimum wall thinning management has been carried out by inputting the measured values as analysis parameter. Even in Japan, it will be possible to reduce the variability of the wall thinning rate evaluation by considering the composition of the piping material composition. In JSME research committee, latest knowledge concerning pipe wall thinning phenomena and state of the inspection technologies of wall thickness have been surveyed and reviewed. In this paper, pipe wall thinning monitoring technologies and chromium measurement technologies are introduced.
In JSME, research committee for the improvement of pipe wall thinning management had been held for 6 years in three phases since FY2008. In this committee, research and surveillance have been conducted on concerned technical area. Succeedingly, the 4th phase started from FY2015 and under this committee, new working group called “Management Rule Revision WG” was set up to review practical application and standardization of the developed relevant technique, especially prediction method. In this WG, implementation of prediction method to the management rule is mainly being discussed. So far in its activities, concept of adding new “Chapter D” providing option of utilizing prediction method to PWR/BWR technical rule has been proposed.
As one of the major activities of the JSME research committee for the improvement of pipe wall thinning management, latest knowledge concerning pipe wall thinning phenomena and state of the inspection technologies of wall thickness have been surveyed and reviewed. Although a complete management of pipe wall wastage consists of prediction, inspection and evaluation, survey of the evaluation part has been running late compared to the prediction and inspection parts. Survey of “Risk-Informed Inservice Inspection (RI-ISI)” was recently initiated in the research committee. In this paper, investigation results about the risk assessment procedure which was developed by the Electric Power Research Institute (EPRI) is introduced. In EPRI's RI-ISI procedure, leakage risk due to pipe failure is evaluated by consequence categories and pipe failure potential. The risk is categorized into seven level and the inspection method or input resources of inspection are determined according to the risk level.
Many overseas countries adopt local thinning criteria that calculate minimum thickness according to the thinning area because pipe wall thinning phenomena caused by flow accelerated corrosion (FAC) and liquid drop impingement (LDI) decrease pipe wall thickness locally. On the other hand, power generating facilities codes in Japan adopt conservative criteria that postulate general thinning. Now the introduction of reasonable pipe wall thinning management that adopts local thinning criteria is highly expected. In Japan Society of Mechanical Engineers (JSME), Management Rule Revision Working Group has been held under the research committee for the improvement of pipe wall thinning management and reviews the application of update knowledge to pipe wall thinning management. This paper introduces the study of domestic and overseas codes that adopt local thinning criteria, the examples of local thinning analysis applying these codes and future issues to adopt local thinning criteria in Japan.