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This paper describes a consideration of the difference in wheel/rail tangential contact force characteristics between in running tests and in laboratory experiments. To improve the accuracy of vehicle dynamics analysis, it is important to obtain the relationship between the tangential contact force coefficient and the slip ratio under realistic conditions. Since these characteristics cannot be obtained by numerical analysis, running tests on commercial lines and laboratory experiments using a twin-disk rolling machine are carried out. On the other hand, under conditions of high slip ratios, these characteristics differ between cases where the tangential contact force coefficient between wheel/rail remains contact and cases where the tangential contact force coefficient decreases. In this study, focusing on the state of the coefficient of friction between wheel/rail, a 3D-MBD model which can simulate vehicle behavior during braking was constructed on the SIMPACK commercial software, and these different reasons and their relationships were discussed. The result clarified that the difference in these characteristics is due to whether the friction coefficient on the contact surface is constant or fluctuating during the measurement by numerical analysis. That is, the characteristics measured in laboratory experiments can be modeled by Kalker’s rolling contact theory with a constant friction coefficient, and the characteristics measured in running tests can be modeled by combining the characteristics obtained by the Kalker’s theory under the conditions of different friction coefficients at each running distance.

The simultaneously iterative procedure proposed by the authors is applied to elastoplastic problems with damage. From the definition of a coupled problem of the weak form of the equilibrium equation and the constraint conditions for plastic yielding and damage evolution at every material point, the authors develop a numerical procedure based on the block Newton method to solve them with simultaneous linearization. In the proposed block Newton method, the consistent tangent can be derived algebraically, and the internal variables, which consist of the plastic parameter and the damage parameter, can also be updated algebraically without any local iterative calculations. Furthermore, the pseudo-stress for the residuals of both the yield condition and the damage evolution law is incorporated into the linearized weak form of the equilibrium equation. Thus, the proposed approach allows us to simultaneously reduce the residuals in the coupled boundary value problems. Some numerical examples illustrate the validity and effectiveness of the presented procedure for elastoplastic problems with Lemaitre damage model.

This report summarized the results of the tests and observations conducted by the “Development of Antarctic Observation Penetrators and Intensive Observation in the Shirase Glacier and Surrounding Area” team of the 64th Japanese Antarctic Research Expedition (JARE-64) at Syowa Station on the sea ice and ice sheet from 22nd December 2022 to 11th February 2023. The main purpose of the tests is to collect primary data for JARE 65 and 66th as the first year of the three-year project. We conducted five tests to evaluate the three elements, penetration, measurement, and communication, comprising the penetrator system.

Electroforming is a highly specialized electrodeposition process for the manufacture of metal components. Based on a bottom-up approach, the process can accurately replicate the shape of a model, known in the industry as a mandrel. Taking advantage of this process, it has long been used for the reproduction of metal crafts. With the progress of semiconductor processing technology, it has become possible to manufacture mandrels with complex shapes in the nano- and micro-scales. As a result, metal structures with fine shapes can be obtained by electroforming using these advanced mandrels. This development trend has led to the emergence of various MEMS devices. To further improve the functionality of the device, it is necessary to develop a new electroforming process using metals with properties superior to those of conventional electroforming using copper or nickel. This article reviews the historical development of electroforming and MEMS, and also introduces several newly developed electroforming processes that demonstrate high functionality.

In a hot strip finishing mill, an unstable lateral steel strip movement called strip walking causes the strip to crash into side guides placed at the entrance of the stand mill, resulting in a tail pinch where the strip is pressed into a folded state. Therefore, strip walking should appropriately be suppressed to prevent tail pinches, requiring adequate strip steering control. To this end, various strip steering control methods have been proposed. Among them, model predictive control, which explicitly considers the motion of a steel strip and constraints on the actuator’s speed, is expected to be of great practical use. However, the disadvantages of this control are that the model’s accuracy affects control results, state variables must be estimated, and its optimization computation is time-consuming. Hence, this paper proposes a method to overcome such disadvantages by adopting a model describing adequately strip walking, model predictive control using discretized inputs, and a deadbeat current observer to estimate state variables. Subsequently, we demonstrated the effectiveness of the proposed method using several numerical simulations together with setting discrete values for the discretized inputs and setting weights in the cost function to be minimized in the model predictive control. In conclusion, it is clarified here that the selection of a set of discretized control inputs, which maximize the leveling speed in minimum time and the proper selection of weights in the evaluation function are crucial for the practical use of model predictive control to prevent strip walking.

For infrasound monitoring in Antarctica, there is a need for infrasound sensors with low power consumption and high resistance to low-temperature environments. A new-type infrasound sensor (TYPE7744N/5002A) manufactured by ACO Co., Ltd. (Japan) with the cooperation of the Earthquake Research Institute, the University of Tokyo, achieves less than half the power consumption of existing models. To evaluate the applicability of the new sensor to Antarctic observation, we conducted a low-temperature (－30℃) test for four types of sensors, including the new one. We compared the results to those from a room temperature (21℃) test and examined changes in amplitude-phase characteristics based on a reference sensor (Model60Vx2, Chaparral Physics), proven in use in polar regions. There were no problems in the operation of the new sensor during the 30 days of the test. Spectral power ratio to the reference sensor changed up to 19% compared to the room temperature test, suggesting that the sensitivity fluctuates with temperature. Phase characteristics were not significantly affected by low temperatures. Future trials are desired to evaluate the long-term stability of the new sensor, e.g., by conducting experimental overwintering observations at Syowa Station.

A series of numerical material tests based on homogenization theory are carried out to characterize the anisotropic elastoplastic and hardening behavior of thermoplastic resin reinforced in one direction by carbon fibers (UD-CFRTP), and a new constitutive model is proposed to describe the characteristic material behavior. First, macroscopic stress-strain curves are obtained from numerical material tests (NMTs) conducted on a unit cell model, i.e., a representative volume element of periodic microstructures, to which uniaxial and combined stress states are applied under various conditions of stress ratios and stress paths. Using the obtained NMTs results, the initial shape of the yield surface and its evolution are investigated in detail. The results suggest that even if a resin has isotopic hardening characteristics, UD-CFRTP exhibits complex anisotropic post-yielding or, equivalently, hardening behavior. Then, a constitutive model that can describe such material behavior is originally formulated, and a step-wise identification strategy is presented to determine the material parameters. Finally, by carrying out verification analyses, we confirmed that the macroscopic stress-strain curves represented by the proposed model can be fitted to those obtained by NMTs with sufficient accuracy for practical use and that the performance of the proposed model is much better than that of a conventional constitutive law.

Rail corrosion is one of the causes of rail breaks. The relationship between rail corrosion state and fatigue strength is still unclear. Therefore, to accurately estimate the fatigue strength of corroded rails, the prediction method for fatigue strength of corroded rails with pitting corrosion by actual stress and stress gradient was investigated. Bending fatigue tests were performed on the rails with pitting corrosion on the bottom surface. At this time, models based on the shape of the rail bottom surface were created, and actual stresses and stress gradients generated at the rail bottom surface were evaluated by the finite element method. When the fatigue test results were evaluated by the actual stress, the bending fatigue strength appeared to be higher when the fracture origin position was inside of pitting corrosion than when it was outside. This was an apparent phenomenon due to the use of actual stress, which could be explained in terms of stress gradients. Furthermore, using the relationship between the correction factor of time strength q, which expresses the relationship between the fatigue strength of new rails and the apparent fatigue strength of the corroded rails, and the stress gradient χ, it is possible to estimate the number of loading cycles that the corroded rails break in the fatigue tests.

Psychological ownership is one of the fundamental notions in marketing and consumer behavior. This idea has increasingly attracted researchers’ attention over the past decade due to the proliferation of digital goods and the sharing economy, both of which are challenging the conventional understanding of “ownership” of products. In this special issue, we shed light on psychological ownership toward various products, such as digital cash, online content, and pop groups, with the aim of gaining a deeper understanding of the mechanism, antecedents, and consequences of psychological ownership.

Application of segment-structured tetrahedral amorphous carbon (ta-C) film on soft metal substrate is proposed to improve wear resistance of mechanical parts. It was generally considered that continuous structure ta-C film was effective when applied to hard materials because it could not follow deformation of substrate material and the film tended to delaminate. In contrast, by applying segment structure on ta-C film, tribological properties of ta-C film coated on soft substrate were further improved, and sliding surface exhibited excellent wear resistance even under high sliding loads. Effectiveness of the use of brass substrate in improving wear resistance was demonstrated through large-scale wear resistant test of valve-plate used in oil pump of construction machine. Segment-structured ta-C coated brass valve-plate reduced maximum wear by approximately 80 % as compared with uncoated brass plate.

In this study, we develop a vibration isolation system using an air suspension with a variable length slit restriction, clarify its dynamic characteristics and build a system that automatically adjusts an equivalent damping coefficient and an equilibrium position of a supported object. The proposed air suspension can provide an optimum damping coefficient by a damping adjustment mechanism. The optimum damping coefficient, which provides the minimum resonance amplitude, increases as mass of the supported object increases. The damping coefficient can be varied by varying slit length of the restriction. In order to vary slit length, the damping adjustment mechanism consists of a fixed plate, which has a partially circular groove and a rotating flat plate faced to the grooved plate. The variable length partially circular slit is formed by the two plates. The damping coefficient is almost proportional to an adjustment angle of the rotating flat plate in the adjustment mechanism. An optimum adjustment angle which provides the minimum resonance amplitude can be obtained by equation showing a relationship between the supported mass and the optimum adjustment angle. The proposed system consists of the air suspension, two pressure sensors measuring atmospheric pressure and static pressure in the cylinder and the reservoir tank, the damping adjustment mechanism, a servo motor rotating the flat plate to tune the adjustment angle and a micro-computer. The micro-computer calculates the optimum adjustment angle which is obtained from the measured pressure data and controls the servo motor to adjust the damping coefficient. The equivalent damping coefficient of the proposed air suspension does not depend on the amplitude even if the slit length is changed by the damping adjustment mechanism. Even if the mass increases up to three times of the nominal value, the minimum resonance amplitude is achieved by using the damping adjustment mechanism.

Magnetic flux modulation gear was proposed in 2001, and many researchers have reported its transmission torque density which has increased dramatically compared to conventional magnetic transmissions. It has some unique characteristics not found in mechanical transmissions such as greaseless drive, high efficiency, quiet drive, low backlash, step-out torque and so on. Therefore, it has potential not only to replace existing mechanical gears but to create new value. For example, it is expected to save maintenance time, improve the working environment (factory or office) by making it quieter, increase efficiency of speed up gears for generators. However, only a few studies about detailed transmission characteristics have been reported. Therefore, authors made a prototype and measured the driving efficiency, loss characteristics, backlash, torsional stiffness, and sound pressure level. In this paper, we report the experimental results and suggest potential used for new applications.

This study concerns a method for detecting the structural anomaly of F type support information board from acceleration measurements. The evaluation of structural anomaly is performed by the autoencoder method．By the proposed method, training of the autoencoder is conducted from data of normal conditions, and diagnosis of the structure is conducted from reconstruction error of the autoencoder. To validate the effectiveness of the method, the method is applied to long-term measurement data from actual equipment. To evaluate the detection accuracy and reliability of the method, the method is applied to sites with fluctuating natural frequencies and sites with stable natural frequencies. As a result, the proposed method with the autoencoder is able to correctly evaluate anomalies of the structure with more than 80% detection and a low false positive rate of 5%, and is able to evaluate the normality of the structure stably over a long period of time.

The aim of this study is to examine the potential of value co-creation in the self-service food retail business, which has been suggested to be low in exploratory research at Zero-waste bulk shops. This suggests the need for a new model for the food retail business beyond traditional norms in Japan. In this study, we conducted exploratory research on the value co-creation process of a Zero-Waste bulk shop from the viewpoint of service-dominant logic. Through field research and user interviews, the study revealed the opportunity of value co-creation based on customers’ characteristic purchase behaviors, such as ‘prepare to visit stores’ and ‘measure an amount,’ which have not been seen in traditional self-service retail businesses to date. The results of analysis using M-GTA to clarify the customers’ value proposition revealed three important factors: ‘values regarding contribution to society’, ‘values regarding self-influence’ and ‘values regarding an ideal lifestyle,’ based on the premise that customers comprehend the background information or context of Zero-waste bulk shops without intervention from store staff and actively engage in the system of a bulk shop.

The seismic resistance of nuclear power plants, particularly those using Sodium-Cooled Fast Reactor (SFR) design, is of crucial significance. This paper presents an innovative three-dimensional seismic isolation system developed to address the inherent challenges of SFR design. Given that these designs necessitate components with a thin wall thickness for achieving high-temperature structural integrity, this can inadvertently lead to a disadvantageous seismic design. Hence, reducing seismic forces in both horizontal and vertical directions is crucial to ensure seismic resistance. This isolation system, designed for application to the reactor building, aims to make it an effectively isolated entity within the larger plant structure. It has been developed to manage seismic forces acting on components, thereby balancing the requirements of both seismic and high-temperature structural designs. The feasibility and effectiveness of this design have been verified through static loading tests conducted on a half-scale model of the system, investigating force-displacement relationships in both horizontal and vertical directions. The results demonstrate that the system's horizontal supporting function provides a stable load path. Additionally, it validates the decoupling of force-displacement interactions under the condition of simultaneous horizontal and vertical loading, an essential presumption in the formulation of the design basis ground motion.

This study considers electric circuits for dielectric elastomer generators (DEG) supplying to low-voltage devices such as sensors for wireless networks. The DEG convert the mechanical energy to the electrical one owing to their capacitance change according to the deformation, and they are expected as the generators utilizing low-frequency vibrations. To supply the electric charge to the DEG for power generation, the self-priming circuit (SPC) comprising capacitors and diodes is widely used. To use the DEG as the power source for the low-voltage devices, voltage step-down elements such as Zener diodes are conventionally introduced, however, the energy loss caused by the elements deteriorates the efficiency. Moreover, to quickly boost the voltage to the operational region from the initial state, smaller capacitors are usually used in the SPC. However, the choice makes the generators sensitive to the leakage charge flowing through the dielectric layers, which is problematic especially when the DEG are operated by low-frequency vibrations. This study proposes a DEG with a voltage-difference-type output circuit that utilizes a rectifier as the output circuit elements connected serially between the DEG and SPC, instead of the step-down elements connected parallel to them. The current flow to the load is governed by the voltage difference between the DEG and SPC, hence we can choose larger SPC capacitors because the quick voltage boost is not required. The output charge as well as the voltage increment and the acceptable leakage charge per cycle is precisely analyzed, from which a systematic way to choose the SPC parameters is also deduced. Experimental results show the validity of the derived formulae and the efficiency of the proposed circuit.

This paper describes a practical wheel/rail tangential contact force model for railway dynamics analysis under running in rainy conditions. In our previous studies, it was confirmed that experimental results of tangential contact force measurement are agree well with Kalker’s rolling contact theory under dry condition with low humidity around contact surfaces. Here, it can be considered that if the ambient humidity around the contact surface become high infinity, the contact surface is under wet lubrication conditions. On the basis of this assumption, in this study, a practical estimation model for characteristics of tangential contact force under running in rainy conditions is proposed by combining the relationship between the adhesive coefficient and velocity measured on running experiments using actual railway vehicles and Kalker’s linear rolling contact theory. Therefore, to verify the proposed model, the tangential contact force measurement experiment using a twin-disk rolling sliding machine was carried out. As a result, it is confirmed that estimated formulae based on the proposed model are well agreed with experimental results even under different velocity conditions, comparing the relationship between tangential contact force coefficient and slip ratio. From these verified results, the proposed model is considered to be a practical wheel/rail tangential contact force model for vehicle dynamics analysis under rain conditions, because the proposed model has the advantage of low calculation cost and can be easily applied to vehicle dynamics analysis based on multi-body dynamics theories.

In this study, we aim to develop individual sloper prototypes offering adaptive comfort to arbitrary parts of the body using personalized torso models created from symmetrized body scan data. This study is categorized by the following three features: (1) adaptive comfort that can be configured for any part of the body, (2) the use of personalized torso models, and (3) the use of two-dimensional triangular polygons rather than one-dimensional measurements. Triangular polygons encompassing the shape of the torso were used to create prototypes. The amount of space was determined by shifting the reference line and reference points on the reference line away from the torso. Personalized prototypes were sewn from sheeting and evaluated with a trial fitting. Both the trial fitting and survey results yielded positive results, confirming the efficacy of the personalized prototypes. [ABSTRACT FROM AUTHOR]

This study describes a method for probabilistically predicting the acoustic properties of porous sound-absorbing materials. Porous materials consist of complex microstructures, and homogenization methods can predict their dynamic properties. However, it is difficult to consider the randomness of the microstructure as in actual porous materials. This randomness affects the acoustic characteristics of the sound-absorbing material. Therefore, we propose a method to consider randomness in the homogenization unit cell and calculate the probability distribution of the sound absorption characteristics. The balance of computational cost with prediction accuracy is essential in predicting stochastic behavior in the multiscale simulation. Thus, we propose a Bayesian approach to achieve both computational cost and prediction accuracy. Random variables are assumed to be the microstructure shape parameters. The product of these probability density functions and the sound absorption coefficient is integrated to calculate the probability distribution of the sound absorption coefficient. The function of the sound absorption coefficient is approximated to calculate this integral by Gaussian process regression. This integral value follows a gauss distribution, and its variance is evaluated as the correctness of the approximation of the integral value. We define this variance as an acquisition function and adaptively obtain additional sampling points where it is minimized. Then, the sound absorption coefficient is recalculated with multiscale simulation at additional points to update the approximate model. Repeating these processes allows the probability distribution to be approximated with reasonable accuracy.

Strip walking is an unstable lateral movement in a hot strip finishing mill that causes the strip to crash into the side guides, resulting in a tail pinch where the strip is rolled in a folded state. Strip walking should be appropriately controlled to prevent tail pinches, and an adequate mathematical model is essential to design the strip steering control. In this paper, the traditional model and a recently proposed model representing strip walking are numerically compared, and the latter is shown to characterize the details of the actual phenomenon. Such a mathematical model derivation makes it possible to use model predictive control to optimally control the strip walking, considering the rate limit constraint of the actuator. However, model predictive control requires time-consuming optimization computation. Thus, control performance deteriorates with longer control periods. In this paper, we propose a new model prediction control method to reduce optimization computation time with discretized control input that enables fast discrete optimization instead of slow continuous optimization. It is also shown that fixing the misalignment between the roll and steel strip centers is insufficient to prevent the tail pinch. Moreover, it is vital to suppress the rotational motion of the steel strip by using numerical simulations.

This paper describes the relationship between a tangential contact force and a slip ratio under various wet condition. In previous studies, the effect of difference in watering amount on the tangential contact force characteristics under wheel/rail contact condition has not been clarified quantitatively. In this study, to investigate the effects of various experimental condition such as circumferential velocity of a test wheel, the amount of water, and contact pressure on the tangential contact force characteristics, a tangential contact force measurement experiment was conducted under the condition of maximum circumferential velocity of 130km/h. As a result, if a small amount of water intervenes on the contact surface, we confirm that the tangential contact force under wet condition sharply becomes small about 30% or less of that under dry condition until the circumferential velocity increases to 30km/h; also, we confirm that the faster the circumferential velocity is the smaller the decrease in tangential force becomes. This tendency is the same under all contact pressure conditions and is qualitatively consistent with the actual phenomenon. Furthermore, to investigate the relationship of tangential contact force characteristics between on laboratory experiments and on test runs, we evaluated the relationship using Polach’ evaluation formula with wet model parameters and an adhesive coefficient planning formula. As a result, it is clarified that tangential contact force characteristics of wheels/rails under wet condition can be estimated on laboratory experiments by correctly evaluating a water film on the contact surface between actual wheels and rails.

Due to the emergence of the online C2C (consumer-to-consumer) marketplace, the new consumer behavior of temporary ownership is gaining popularity. Temporary ownership is defined as consumer behavior of selling products that they own temporarily, which were purchased for self-use. In this paper, the author envisions, explicates, and delineates temporary ownership behavior. Then, the paper highlights the similarities and differences with concepts such as liquid consumption, access-based consumption, collaborative consumption, and sharing economy. Finally, the paper debates the future research directions regarding temporary ownership relating to consumer decision making and psychological ownership, and discusses the managerial implications.

In recent years, the development of technologies for "connected factories" based on the Internet of Things (IoT) has become important, and industrial robots are required to operate autonomously based on sensing technologies and their data. In this paper, we focused on the polishing work with a cooperative robot, and discussed a method to integrate the technology of the developed wireless vibration monitoring system with the internal information of the servo. In particular, we attempted to construct a novel finishing system that utilizes the internal information of the force sensor installed in the base of the cooperative robot not only to detect human contact but also to improve the accuracy of machining. We estimated the rough-endmilling state from the in-process monitoring the vibration with a wireless tool holder system and the internal information of the servo obtained during endmilling operation, and also integrated the finishing process using the newly developed system considering rough endmilling information with a cooperative robot.

Thermoplastic resins, which can be used for matrix materials in fiber reinforced thermoplastics (FRTP), have distinctive nonlinear characteristics that depend on temperature and strain rate compared to conventional materials such as metals and thermosets. Therefore, in order to use FRTP as a structural material, it is necessary to properly measure its material behavior, adopt an appropriate constitutive law, and accurately identify the material parameters. Conventionally, although there have been reports on the nonlinear behavior of thermoplastic resins, most of them employ a single constitutive law such as plasticity or creep using data measured under specific conditions. In this study, adopting a viscoelastic-viscoplastic-damage constitutive law to represent the material behavior of thermoplastic resin, we propose a hybrid identification method that can determine the material properties of by the combined use of the results of dynamic mechanical analysis and uniaxial cyclic loading-unloading test. Specifically, material parameters for viscoelasticity are identified from the complex moduli of elasticity obtained from the dynamic mechanical analysis, and those for viscoplasticity as well as the damage and time-temperature shift factor in low temperature range are identified from the uniaxial cyclic loading-unloading test. Differential Evolution, one of the optimization algorithm, is adopted to identify the parameters. Conducting some material tests, we confirm the effectiveness of the proposed method in reproducing the nonlinear material behavior of three typical thermoplastic resins: polycarbonate, acrylic resin and thermoplastic epoxy resin. In addition, the identification accuracy is significantly improved by the modification of the time-temperature shift factor, which has been determined by dynamic mechanical analysis, using the results of uniaxial cyclic loading-unloading tests in the low temperature range.

The simultaneously iterative procedure proposed by the authors is extended to hyperelastic shells. The weak form of the equilibrium equation and the plane stress condition at every material point are defined as a coupled problem, and a numerical procedure based on the block Newton method to solve them with simultaneous linearization is developed in this paper. In the proposed block Newton method, the tangent moduli can be constructed algebraically by eliminating the internal variables, which are also updated algebraically without any local iterative calculations. In addition, the pseudo-stress for the residuals of plane stress state is incorporated into the linearized weak form of the equilibrium equation. Hence, the proposed procedure enables us to decrease the residuals in the coupled boundary value problems simultaneously. Some numerical examples demonstrate the validity and the effectiveness of the procedures in hyperelastic shells.

There are many vehicles passing through on main road. On main roads, various safety countermeasures are constructed for securing traffic safety of a large number of vehicles. For example, separate sidewalks and driveways, or constructing median strips to prevent a head-on collision with vehicles going in the opposite direction, etc. On the other hand, the width of the residential areal road is narrow and the center line that separates the round-trip traffic of vehicles is not drawn. In addition, the separation of sidewalks and driveways is incomplete. Therefore, the residential areal road is not suitable for many vehicles passing through. For these reasons, under normal traffic conditions, many drivers choose to drive on main roads. However, when traffic jams occur on the main road, the number of vehicles flowing from the main road to the residential areal road increases in order to avoid the traffic jam. In a previous study, the authors have clarified that the traffic volume of parallel residential areal roads increases during the time when the length of traffic jams or the time required to pass the intersection becomes long on the main road during the morning and evening commuting hours. Then, it was clarified that the frequency of sudden braking on the residential areal road and the frequency of "dangerous experiences" by junior high school students passing through are increasing. In this study, we investigated the section where traffic jams occur during the morning and evening commuting hours of National Highway No. 2 in Fukuyama City, Hiroshima Prefecture, and the residential areal roads parallel to this section. Then, the authors verified that the residential areal road is a loophole of National Highway No. 2 by performing a traffic route analysis using ETC2.0 data. In addition, by analyzing the traffic accidents that occur on this residential areal road , we clarified the dangers hidden in this road used as a loophole, importance appropriately.

Diesel or gasoline particulate filters are included in almost all vehicles to clean emission gas from internal combustion engines. On the other hand, a new regulation for vehicle noise emission has been into operation, and noise from exhaust system must be reduced. Although mufflers with expansion chambers and sound-absorbing material are mainly applied to reduce noise emission, diesel or gasoline particulate filter can reduce noise transmitted through the filter. In this study, sound transmission loss of diesel or gasoline particulate filter is measured and some amount of sound transmission loss is found to be obtained. Then, we propose a method to predict sound transmission loss of diesel and gasoline particulate filters from a microstructure model of ceramic porous material that is applied for filters. Homogenization method for sound-absorbing poroelastic material based on the asymptotic expansion approach is applied in this study. This method was proposed by one of the authors of this study. Microscopic structure images are obtained by scanning electron microscope, and the size of pores are identified by image analysis. Homogenized properties, such as equivalent density and bulk modulus are calculated by performing microscopic analysis with unit cell finite element model. Finally, sound transmission loss is obtained by macroscopic calculation with homogenized properties. Numerical sound transmission loss agrees well with sound transmission loss measured by acoustic tube and simplified exhaust system.

This study aims to establish a loading test method on test tracks composed of a single rail fastening at rail joints. The authors construct FEM models for railway tracks which represent the rail joint parts accurately and perform the FEM analysis. The FEM results are in good agreements with the results of a loading test on a test track composed of plural rail fastenings. Based on the FEM model, the authors proposed the loading test method on test tracks composed of a single rail fastening and compared the test results of a single rail fastening and plural rail fastenings. As a results, it becomes clear that rail head displacements and rail tilting angles obtained from a single rail fastening are in good agreement with those obtained from the plural rail fastenings. Therefore the proposed method of loading test on a test track composed of a single rail fastening based on the FEM model is available to evaluate the performance of the rail fastenings systems of rail joints.

At Tokyo Metropolitan Vocational Skills Development Center, job trainings are provided for job seekers to attain basic skills for employment. We carried out 20 years manufacturing competition for improvement of the skill and interest to manufacturing. The competition was divided into four branches and the teaching material of the machine course is a Stirling engine. At the machine course of the Itabashi school, we worked on the production of Stirling engine to acquire the digital manufacturing technology. The digital manufacturing technology is a design technology by the 3D CAD, programing for the NC machine and operation of the NC machine. We reported the class situation, the production of Stirling engine for five years from 2007 to 2012. And we verified the class effect by the acquisition degree investigation and the questionnaire survey from students. As a result, those class training succeeded considerably in their job search. It was made clear those class training had the good effects for the students to acquire the skill of digital production technology. And we researched company about the introduction situation of the digital production technology and completion students about the situation after the employment passing for a certain period of time about 10 years.

The thermal shrinkage technique, which uses shrinkage strain and shrinkage zone to calculate welding distortion, is expected as a simple simulation to predict the welding distortion of large weld structures. In previous studies, parametric study was performed for bead-on-plate welding and optimum input data settings was clarified, which were the shrinkage strain of −0.012 and a shrinkage zone in which the maximum temperature reached 500°C or more for structural steel. In this research, the thermal shrinkage technique with established input data settings was applied to a construction machinery structure to validate whether the input data settings obtained in the previous study for test specimens is applicable to large weld structures. The analytical model is a construction machinery structure with dimensions of 3.9 m in length, 2.7 m in width, and 0.9 m in height, and has a 40-pass fillet welded joint. The welding distortion analysis using thermal shrinkage technique was conducted with the optimum input data settings. Thermal elastic-plastic analysis considering moving heat source was also performed to compare the numerical results by the thermal shrinkage technique and thermal elastic-plastic analysis. Numerical results revealed that the displacement distribution after 40-pass welding of the construction machinery structure obtained by the thermal shrinkage technique was in good agreement with that obtained by thermal elastic-plastic analysis. A more detailed evaluation showed that the displacement in each welding pass obtained by the thermal shrinkage technique accurately reproduced that obtained by thermal elastic-plastic analysis. The calculation time of the thermal shrinkage technique was 1/7 for the construction machinery compared with thermal elastic-plastic analysis, which clarified that calculation time could be shortened. Our results show that the thermal shrinkage technique with optimum input data settings could be applicable to large weld structures to predict welding distortion.

Due to the emergence of online flea market apps, consumers have begun to shop in retail shops with the intention of reselling in the future. In this paper, the author examines the effect of secondary market options on the shopping behavior in the primary market. More specifically, the paper examined the attractiveness of resale conditions, such as resale price and duration until settlement, at the secondary market using conjoint analysis. The analysis results indicate that although price and product attributes are important in decision-making at the primary market, the conditions at the secondary market also have positive utility. Moreover, the sellers on the online flea market app have relatively low price sensitivity at the primary market, and marginal willingness-to-pay of the conditions in the secondary market is higher compared with other user segments. The presence of a secondary market has the potential to raise consumer’s willingness-to-pay at the primary market.

This report describes the results of meteorological observations at Syowa Station from February 1st, 2014 to January 31st, 2015, carried out by the Meteorological Observation Team of the 55th Japanese Antarctic Research Expedition (JARE-55). The observation methods, instruments, and statistical methods used by JARE-55 were the same as those used by the JARE-54. Remarkable weather phenomena observed during the period of JARE-55 are as follows: 1) The number of occurrences of the blizzard was 23 times, which was smaller than 24.6 of annually average times from 1981 to 2010. Blizzard occurred in January 2015, the maximum wind speed (10-minute average) was 41.8 m/s, the maximum instantaneous wind speed was 51.4 m/s, both records for this month and during the period of JARE-55. Blizzard occurred every month except November. 2) The monthly sunshine duration in February 2014 was only 114.6 hours, a record low for this month. 3) On March 18th, 2014, the daily low relative humidity was 18%, which was the same value on July 11th, a record low since February 1981. 4) The amount of total ozone over Syowa Station from mid-August to mid-November was often less than 220 m atm-cm used as a target for the ozone hole for most of this period. The value for October 7th was 139 m atm-cm, which marked the minimum value of year 2014.

Rocks generated from tunnel construction projects for roads and railways throughout Japan have often leached out hazardous trace elements, such as arsenic (As) and selenium (Se). In nature, the oxyanionic species of As and Se have a variety of chemical species, so speciation is one of the crucial factors in their migration through natural geologic media. In this study, column experiments consisting of four types of crushed rock samples containing As and Se, and a river sediment (RS) as an adsorbent obtained near the tunnel construction site were conducted to evaluate the leaching and adsorption behavior of arsenite (As (III) ), arsenate (As (V) ), selenite (Se (IV) ), and selenate (Se (VI) ). The results showed that the dominant speciation of As and Se in the effluent from the rock layer was As (V) and Se (VI), and that the addition of a bottom RS adsorption layer or the mixing of RS with the rock layer decreased the leaching concentrations of As (III), As (V), Se (IV), and Se (VI). Cumulative leachability (CL) for each speciation through the column experiments was calculated to evaluate the amounts of As and Se retained in RS. The calculated CL showed that the bottom RS layer or mixing of RS with the rock reduced the CL of As (III), As (V), Se (IV), and Se (IV) ranging from 60 to 89%, 73 to 89%, 9 to 75%, and 36 to 60%, respectively; however, mixing of RS with the rock layer was ineffective in decreasing CL of Se (VI). The reduction of CL may be due to adsorption and/or coprecipitation by iron and/or aluminum oxides contained in RS. These results indicated that utilization of RS for the bottom adsorption layer was effective in reducing As and Se concentrations irrespective of their speciation, although that of mixed with rock layer was effective only in reducing As concentrations irrespective of their speciation.

In recent years, as measurement devices have advanced due to sensor and information technology, we have been able to measure bat swing data just after baseball impact. Therefore, the purpose of this study was to examine the characteristics of a batter’s swing using batting skill assessments from baseball coaches with significant experience. Finally, the practicality and effectiveness of baseball coaching methods, particularly for batting, were verified through this study. The subjects were 25 male university baseball players (age: 19.8 ± 1.0 yrs, body height: 174.5 ± 5.4 cm; body weight: 72.8 ± 5.1 kg). The participants were instructed to hit the ball placed on a tee stand. Nine types of tee-batting positions (course / height) were set for each participant depending on the upper and lower limits of the strike zone according to the baseball rules. Our main findings were as follows: 1) The swing characteristics (Depth: swing time and vertical bat angle, Height: head speed, rolling angular velocity, bat radius of rotation, horizontal bat angle, and vertical bat angle, Course: rolling angular velocity) varied with respect to ball positions, 2) Through batting skill assessment by two baseball coaches with significant experience, a good batter’s swing can be characterized as high bat speed, short swing time, and high efficiency of rotational movement around the vertical axis. Additionally, the coaches suggested that for a good batter’s swing, the vertical bat angle should be stable and smaller than 9°. These results provide useful information on assessment of bat swing training methods and exercises to hit the ball to different positions. Furthermore, this study can aid baseball coaches and/or players to objectively analyze a bat swing of a player.

A high speed electric motor with a small reducer and high power transmission efficiency realizes a powertrain system with high power density because electric motors can be miniaturized to increase the rotational speed. The transmission performance and behavior of meshing gears or traction drive transmission elements with a high-speed reducer have not been clarified at such high rotational speeds due to experimental difficulty. Therefore, a high-speed transmission tester was designed and built to enable experiments at 50,000 rpm, without the use of special motors or measuring instruments, by increasing the speed using the ratio of the test roller or gear radii. The measurement results almost agree with the known values and trends, confirming that this tester can be used to perform measurements at high speed. Because the traction coefficient and transmission efficiency do not decrease drastically at high rotational speed, discontinuity was not found in the mechanism of traction expression. At high rotational speed and low torque, a traction drive has a higher transmission efficiency than that of gears, and this is more pronounced at higher rotational speed. At low speed and high torque, gears are more efficient. Therefore, this study demonstrates that gears are suitable as transmission reduction elements below 25,000 rpm, and traction drives are suitable for rotation speed reduction above 25,000 rpm.

Quantitative evaluation of uncertainty in acoustic properties is an essential issue to improve product quality. The acoustic properties of porous materials, such as sound absorption coefficient, are affected by variations in microstructure and material properties during manufacturing. In particular, the microstructure uncertainty significantly affects the variation of the sound absorption coefficient, and a trial-and-error approach using prototypes is necessary for its evaluation. This study proposes a method to obtain the probability distribution of the sound absorption coefficient by combining the homogenization method with the probabilistic approach under the microstructure uncertainty. Defining the porosity and the homologous deformation of the unit structure as random variables, the probability distribution of the sound absorption coefficient was calculated using the homogenization method and the Monte Carlo simulation or perturbation method. The result by the perturbation agrees well with the Monte Carlo simulation result, and the uncertainty of the sound absorption coefficient can be evaluated with our proposed method. Using the method developed in this study, the effect of microstructure variation on the sound absorption properties of porous materials by simulation can be predicted. Our method can contribute to the development of new sound-absorbing materials.

More than a decade has passed since the emergence of major social media services such as Twitter and Facebook, and these services have attracted considerable attention from both practitioners and academics. The aim of this special issue is to re-examine the impact of social media in marketing. Consumer engagement behavior on social media was expected to enhance the marketing activities of firms in various areas, including advertising, customer support, and new product development. Along with these high expectations, the negative impacts of social media, such as backlashes against certain people or brands, spread of fake news and fake reviews have also affected firms and consumers. In this special issue, we shed light on various aspects of social media, including consumer enthusiasm and collective behavior, the resulting positive and negative bursts in social media, product reviews and their helpfulness, and usage patterns of social media by user segment.

In this paper, the simple dynamic model for calculation of the axle-box acceleration (ABA) is established for conveniently detecting rail breakage on trains. Track circuit based signaling system, whose functions are detection of vehicles and rail breakage, is tend to be replaced by Communication Based Train Control system because it is expected to reduce the cost for maintaining equipment along railways. In order to maximize the advantage of reduction in costs, the way to detect rail breakage on the vehicles should also be established. The running tests on the rupture part of rails on a ballasted track and a ballasted ladder track are conducted, and the ABAs obtained in each test are analyzed. The dynamic models corresponding to two types of tracks consist of beams on elastic foundation are established. Subsequently, simple vibrating models are derived from beams so as to consider the frequency characteristics of coupled vibration with tracks and vehicles. The results show that the difference of boundary conditions on rails changes the masses and springs contributing to vibration of the systems, changing the eigenvalues of vibration. These changes are reflected to the ABAs in such a way that a peak of resonant frequency of them gets lower when a vehicle running through broken rails. It is assumed that the rail breakage can be detected without wayside infrastructures by acquiring the ABAs and monitoring the change of them in the frequency domain.