Experimental investigations on the drag reduction phenomenon over riblets have been made in turbulent boundary layer under adverse pressure gradients. The local wall shear stress was determined by a direct measurement device, and mean velocity and turbulence intensity profiles were obtained by a single hot-wire probe and a constant temperature anemometer. The error due to the pressure gradients on the wall shear stress measurement is successfully eliminated from analysis of pressure distribution on the lip of the floating element. Under adverse pressure gradients of the order of β ≅ 0.4, the wall shear stress reduction rate of the trapezoidal grooves riblets with dimensions 9.5 < s⁺ < 11.6 agrees with the reduction rate under zero pressure gradients. The logarithmic mean velocity profile can be recognized over riblets and Kármán constant 𝜅 keeps almost the same value for smooth and riblets surface. However, the additive constant is increased by the wall shear stress reduction over riblets. In the streamwise turbulence intensity profile normalized with the wall units, the maximum value is the almost same for smooth and riblets, but the position of the maximum value y⁺ is slightly shifted upwards from the wall to the far side for riblets.

Flow-Accelerated Corrosion (FAC) is a pipe wall thinning phenomenon to be monitored and managed in power plants with high priority. Its management has been conducted with conservative evaluation of thinning rate, and residual lifetime of piping based on wall thickness measurements. In tee joint with a curvature part called a "crotch" in the area where pipes meet, the radius of curvature of the crotch becomes small, especially when the pipe diameter is small, and the flat tip of the probe commonly used in conventional UT (Ultrasonic Testing) measurement cannot sufficiently contact the measurement surface of the crotch, making wall thickness measurement difficult. The purpose of this study is to develop a method for estimating the maximum wall thinning of a tee joint based on detailed wall thinning trends at and around the crotch, and to introduce a multiplication factor necessary for estimating the wall thinning. It was found that depending on the flow pattern, the maximum amount of wall thinning occurs at the crotch. It is suggested that the angular position of the tee joint curvature where the maximum value appears can be determined by the design value of the piping. The trend of the multiplication factor can be arranged according to the design value of the piping, and its maximum value was found to be approximately 1.5.

In a previous study, we had proposed a method for detecting abnormalities using an Autoencoder. It considers the amplitude value of each frequency spectrum while performing the FFT analysis of time-series data. In this study, we applied this method to detect abnormalities in pressure washers. In particular, we verified its detection accuracy on the artificially-generated anomaly data. The results showed a deteriorated detection performance for a varying spectrum amplitude near the resonance frequency. Therefore, in addition to the conventional autoencoder, the proposed method further improves anomaly detection accuracy by treating the spectrum as a lumped spectrum in a predetermined frequency range. The effectiveness of the proposed method was verified using data obtained from equipment anomalies. In conclusion, the proposed anomaly-detection method can robustly cope with frequency fluctuations near the peaks and detect anomalies with a accuracy higher than that of the conventional anomaly detection method, which uses only an autoencoder. Thus, the proposed method can detect anomalies even before factory become aware of them.

Seismic design for equipment and piping systems typically conducts linear evaluations using maximum response accelerations or response spectra of structures. However, gaps exist between structures and support structures in these systems, which can affect their response behavior. This study aimed to confirm the margin between the linear evaluation and the evaluation that considers the effects of these gaps. Vibration experiments were conducted on a beam and support structures with gaps to measure strain and acceleration at the center of a test specimen. The experiment conditions were varied by changing the input acceleration levels and gap sizes. The results indicated that increasing the gap size led to a decrease in strain and an increase in acceleration. To evaluate the effects of gaps, a strain response factor was defined as the ratio of the maximum input acceleration to the strain, and a normalized gap was defined as the ratio of the maximum input displacement to the gap. The relationship between the strain response factor and the normalized gap can be divided into five characteristics, and it was indicated that increasing the normalized gap led to a decrease in the strain response factor. Additionally, an effective acceleration was defined in proportion to the strain, and an effective acceleration response factor was defined to be the ratio of the maximum input acceleration to the effective acceleration. The effective acceleration response factor without a gap was obtained from the response spectrum using input wave. A proposed method was developed to explain the observed behaviors of five characteristics between the effective acceleration response factor and the normalized gap. The evaluation results using the proposed method were compared with the experimental results. The comparison results indicated that the evaluation results can reproduce the experimental results. Therefore, the proposed method provided a way to confirm the mergin between the linear evaluation and the consideration of gap effects in linear seismic design for equipment and piping systems.

The physical mechanism underlying wire rope cut-in in multilayer drums was experimentally investigated. Although the wire rope appears to be correctly spooled on the drum, hoisting the load can cut the spooling wire rope into multiple layers, leading to mis-wrap or entanglement. Such irregularities may result in rope damage or reverse winding, necessitating repairs. The hand winch testing results indicated that LEBUS drums exhibit greater resistance to cut-in compared to ungrooved drums; in particular, LEBUS drums require a lower pre-tension load to prevent cut-in than ungrooved drums. Moreover, in the LEBUS, the spooling wire rope typically cuts through in a single layer, whereas in ungrooved drums, the spooling wire rope cuts deeper through multiple layers, increasing the likelihood of entanglement or reverse winding. The simultaneous slipping of several wraps in the surface layer was observed as a contributing factor to cut-in in LEBUS drums.

The purpose of this study is to elucidate the origin of the additional response signals arising from the surface topography of samples during piezoresponse force microscopy (PFM) measurements. Periodic mountain-shaped protrusions with triangular cross-sections were fabricated on the surface of a silicon single crystal, a material with no inherent piezoelectricity, and PFM measurements were performed. The results indicated that when the measurement sensitivity direction of the PFM and the ridge direction of the protrusions formed specific angles, piezoelectric response images influenced by the surface topography were generated. Two-dimensional electrostatic field analysis confirmed that the contribution of converse flexoelectricity to this phenomenon was very small and negligible. Conversely, PFM measurements conducted both in-plane and out-of-plane on the sample, as well as measurements on a conductive material, revealed that the additional piezoelectric response - which was dependent on the surface topography - was induced by electrostatic forces due to the charging of the sample surface. The signal intensity was found to increase as the angle between the direction of the inclined plane and the in-plane sensitivity direction became smaller, as the tip diameter increased. These findings highlight the importance of accounting for the dominant influence of electrostatic forces in the interpretation of piezoelectric response data. Furthermore, they provide valuable insights into the effect of sample topography on PFM measurements.

We have repeatedly considered Holographic Neural Network (HNN) emerged by Sutherland ,J. G. as a causable machine learning. As a result, we developed FQHNN (Fuzzy Quantification Theory Embedded Holographic Neural Network) which has been already applied to various problems successfully because of its causality and versatility. It is important for the system itself to grasp the concentration of the driver especially in the case of auto-driving level 3 where the driver must appropriately respond to requests to intervene for driving from the system. We are progressing the research of the auto-driving car from the point of cooperation between the system and the driver with the thought that the system must continue the driving depending on the situation of the concentration of the driver. To carry out this research, it is realized that the causable machine learning holds the key of the success and here we develop FQHNN to the time series problem. It is confirmed the excellence of the FQHNN in the time series against LSTM (Long Short- Term Memory). We try to develop concentration confirmation system with facial expression analysis based on FQHNN in the time series. At last, we discuss whether the system can be applied to judge the concentration of the driver of auto-driving car in real time.

In recent years, efforts to promote energy conservation have become more active, and there is an increasing demand for high-efficiency motor coils. The efficiency of permanent magnet motors is closely related to manufacturing engineering. By winding copper wire at high density, not only coil resistance but also energy losses due to coil heating can be reduced. However, manufacturing defects reducing coil density can occur in the winding process. When they occur, rewinding of copper wires must be performed aligning several parameters based on the experience of operators. Therefore, this paper proposes a simulation method for the dynamic deformation of copper wire in the winding process to predict defects in the motor coil manufacturing process. First, the copper wire is assumed to be an elastic-plastic body and modeled discretely as a set of mass points connected by springs. The deformation of the copper wire is considered to be expansion, contraction, bending, and twisting. In particular, an object coordinate system for each mass point is introduced to express the twisting deformation. Next, to maintain the consistency of the copper wire, constraints between the spatial coordinates of each mass point and the direction of the object coordinate system are formulated. Under these constraints, the equations of motion are solved to predict the dynamic behavior of the copper wire. In this paper, the simulation domain of the winding process is limited to speed up the calculation. Since the copper wire is supplied from outside the simulation domain, constraints on the supply point are also formulated. Finally, a simulation of winding the copper wire around a rectangular core was performed. The simulation results showed that the defect of loose winding, called "bulging" is related to the rotation speed of the core and the tension of the supplied copper wire.

In the manufacturing industry, knowledge transfer from experts to beginners is getting to be important issue because of decreasing number of experts. To support knowledge transfer, various support systems have been developed. However, it is difficult to present knowledge that matches the user's skill level. On the other hand, techniques for judging user's skill level using biological information such as EEG (Electroencephalography), HRV (Heart rate variability), and gaze have been developed. In this study, we focused on the gaze, which is easier to measure than EEG and HRV. It has been reported that the content of work and skill level were estimated using machine learning from the features of gaze. However, the features of the gaze used differ depending on the subject. In this study, we focused on gaze and pupil size to evaluate the differences between expert, intermediate, and beginner in a task of searching for vortices in fluid simulation images. As a result of comparing the gaze and pupil size of 8 experts, 8 intermediates and 8 beginners, it was found significant differences in the fixation duration, the number of fixations, and the number of gaze movements. Although there was no significant difference in pupil size, which indicates cognitive load, between experts and intermediates, both groups had larger pupil sizes compared to beginners. Experts explore vortices with high cognitive load over long periods and many gaze movement, intermediates explore vortices with high cognitive load over short periods and few gaze movement, and beginners explore vortices with low cognitive load over short periods and few gaze movement. We used Random Forest to learn the fixation duration, number of fixations, number of gaze movements, and pupil size, and classified the skill level with the accuracy of 83.1 ± 11.6% using the features with high importance. These results imply the gaze shows the difference in the users' skill levels and show the prospect of presenting appropriate knowledge to the user of the design support system by using the gaze-measurement result.

The intracellular actin cytoskeleton binds to non-muscle myosin II to form stress fibers (SFs) with a diameter of several hundred nanometers, which generate intracellular tension and control cell shape and movement. SFs generate a contractile force and transmit it to focal adhesions, which is essential for regulation of cell adhesion to extracellular matrix and cellular sensing of extracellular mechanical environments. Although several studies have been reported on the mechanical and contractile properties of SFs, it has not been clear how completely severed SFs are repaired and regenerated. In this study, SFs located at the periphery of living myoblasts (C2C12) were severed using a pulsed laser and their contraction and repair process were analyzed by fluorescence observation. SFs immediately contracted after their severing. The contraction process of SFs was accurately fitted using the first order lag model, indicating viscoelastic behavior. We found that SFs have a potential to repair their structures: in approximately 80% of the cells, the structure of severed SFs was gradually repaired over several minutes with contraction behavior (Repaired group), but not in some cells (Unrepaired group). The contraction rate α and contraction time constant τ of the SFs in the unrepaired group tended to be larger than those of the repaired group. These results suggest that the repair process of the severed SFs is possibly affected by the intrinsic mechanical tension of the SFs and viscous resistance from the intracellular components around the SFs which is generated by the sliding motion caused by the fiber contraction.

In recent years, railway operators have been promoting the construction of unmanned stations, and the ratio of unmanned stations is increasing year by year. However, unmanned stations have a disadvantage for passengers who need assistance when boarding and disembarking, in that they cannot receive on-demand assistance. It has been reported that the rate of unmanned stations is higher on regional lines than in urban areas. Since many local routes are not electrified, most of the trains operated are diesel railcars. Diesel railcars are vehicles powered by diesel engines, and because the engine is mounted under the bogie floor, access to the vehicle floor is via a step structure that is raised one step from the vehicle entrance. For wheelchair users, the accessibility to the multi-level entrances/exits of diesel railcars via existing grooves in station platforms is significantly reduced. In this paper, we propose a mechanism and its control system to assist wheelchair users in getting on and off public transportation vehicles. This mechanism has a mobility function that combines lifting and lowering with a ground arm and a running function with wheels, and consists of an arm mechanism with two degrees of freedom and a running mechanism that can be added to the front and rear of an existing wheelchair. This paper demonstrates the feasibility of using this mechanism to enable a wheelchair user to board and disembark from a diesel railcar, and also discusses step-crossing motion that quantitatively suppresses the jerking motion that occurs when going up and down steps.