The lower limb has a complex structure, and the mechanical mechanisms, including the combined action of hard and soft tissues, are not yet fully understood. Additionally, it plays a central role in standing, sitting, and locomotion movements. Because the lower limb supports the body during these activities, it is subjected to loads on the joints and muscles, making it a site where various conditions such as osteoarthritis and muscle strains frequently occur. Understanding lower limb mechanics in these conditions is crucial for disease prevention and ability enhancement. In the field of human motion analysis, several studies have reported that human parts were modeled using finite element method (FEM) to analyze deformation of soft tissues, and modeled as rigid bodies in dynamics simulation system to reveal the dynamic motion behavior. However, FEM is computationally expensive, and rigid body simulations struggle with soft tissue deformation. This study aimed to create a musculoskeletal dynamic model of lower limbs to represent the realistic behavior of joint movement and soft-tissue deformation as a dynamic simulation using a rigid-body model for bones and a soft-body model for soft tissues via a spring-damper-mass system. The model incorporated Hill’s model for muscle contraction and successfully demonstrated detailed hip and knee joint behavior. Additionally, using the constructed simulation system, the strain of the ACL and PCL during knee flexion were measured.

Endoscopists are considered to be at high risk of developing musculoskeletal disorders (MSDs) due to prolonged periods of time in the same posture and twisting positions.Upper Gastrointestinal Endoscopy requires meticulous techniques focusing for hours, through endoscopic images on a monitor, physically draining situations.Therefore, they are sometimes forced to take time off from work due to physical pain.There is currently no research on quantification of the actual physical burden on endoscopists performing upper gastrointestinal endoscopy.Therefore, this study is aimed at quantitatively visualize the differences in muscle tone between standing up and Sitting down endoscopists during upper gastrointestinal endoscopy and to consider the burden on the body.Then, we devised a method for performing an analysis of the physical burden on the surgeon during surgicaloperation using a musculoskeletal mathematical model, which has been proven to be useful in the analysis of physicalmovements of car drivers and athletes. And by using this method, the physical burden on the surgeon during surgery could be quantified, and the purpose of this study could be achieved.

When most people hear the word robot, they probably think of a human-shaped robot. However, software engineers may think of RPA (Robotic Process Automation). Whether it is hardware or software, robots basically operate as instructed by humans and perform human work. In other words, a robot is a servant. This is because the current industrial society brought about by the Industrial Revolution is centered on things, and the amount of work required to do so has increased dramatically over time. As everybody knows, society changes with time. The industrial society is getting close to its end, and now it is time to think about the next society. The biggest problem with the industrial society is that it consumes too much energy, and it is no longer possible to maintain the industrial society. Furthermore, the reason that the industrial society cannot be maintained is the rapid aging of the population, we cannot securea working population. However, the population is increasing in developing countries. But these people are not able to support the industrial society due to the lack of literacy (skills, knowledge). , the Industrial Revolution introduced the division of labor. Before that, we enjoyed a unique characteristic that only human have, i.e., We think about the future, and worked hard to make those dreams come true. This is self-realization, and it allows humans to feel the greatest happiness and sense of accomplishment. However, because of the division of labor, we began to work for others, and to this day we have lived without being able to feel the greatest happiness that humans are originally capable of. A big problem for the elderly, especially men, is that they make friends at work, so when they retire from work, they lose friends and become lonely. Therefore, how to overcome this sense of loneliness and bring tomorrow to the world of the elderly, too, is an important issue. In this presentation, how to tackle this issue will be discussed.

The capability to make unconscious and intuitive judgments for the mechanics aspect of an object is called Mechanical Kansei, and there are attempts to elucidate how this capability is utilized in the realization of structural rationality within the design process. In this study, we focus on the fact that there are many descriptions of the internal force-flow within the structure in explanations of functional beauty and design education; and assume that the ability to intuitively recall the flows without mechanical analysis is based on Mechanical Kansei. We try to reproduce that intuitive process by training a deep learning network model that can generate mechanical loading patterns, e.g. equivalent stress, principal stress, and signed Tresca stress, inside the structure under various conditions without a mechanical model. The obtained network model implies a mapping from structural conditions to the mechanical loading patterns and could help to understand the Mechanical Kansei.

Traditionally, optical motion capture systems have been widely utilized to accurately obtain athletes’ pose data at the laboratory settings. However, it is impossible to use such wearable motion capture in real races to analyze the performance of participating athletes. In this study, we analyzed sprinters’ form using markerless posture recognition technology, specifically OpenPose, and investigated the feasibility of applying pose estimation to sprint running.

This research aims to develop the method for classifying the break-up patterns of PLTFs using a deep learning. First, PLTFs judged to be good at Stage_1 (from after-blink to PLTF break-up) were classified into [Normal_1] class. On the other hand, for bad PLTFs in Stage_1, their images were classified into three classes [Dimple_1], [Line_1], and [TAL_1], where dimples, lines, and thinner aqueous layers (TALs) were produced in Stage_2 (after PLTF break-up), respectively. Then the 4-calss (Normal_1, Dimple_1, Line_1, TAL_1) classification of images in Stage_1 was performed using the transfer learning of VGG19 that is the model developed by the Visual Geometry Group (VGG) at Oxford University. For Stage_2, the images which were judged as the bad PLTF in Stage_1 were classified in the 3-classes of [Dimple_2], [Line_2] and [TAL_2] using the transfer learning of VGG19.

One of the problems with using PMIs for inhalation treatment is that there are cases in which patients fail to spray a dose at proper timing. In order to solve this problem, for this research, we developed an automatic spraying device (automatic inhaler) that automatically sprays according to the monitored timing and studied the changes in inhalation status under the continuous use of the device.As a result, because the subjects were not required to spray a dose at proper timing with the use of the automatic device, we could approximate the inhalation speed and volume to the desired values. Also, as some of the subjects learned the proper timing through the continuous use of the device, they became able to spray a dose at the proper timing even without using the device. However, because the device requires a medicine bottle to be pushed a force of over 50N to spray, even though the subjects started to push their bottles with perfect timing, some ended up missing the optimal timing to spray.

Irregular motion of device tip during endovascular treatment may cause damage to vessel wall. This motion is called jumping phenomenon. The purpose of this study was to detect signs of this motion and to find a method to suppress the occurrence of jumping. A guidewire was inserted into four different vascular phantoms that simulated actual vascular shapes. The guidewire tip is directed to the right or left in the direction of advance. The device motion was recorded by a camera from one direction. Device shapes were extracted from images divided from the video. The distance of guidewire tip moved, the change in strain energy, and the change in local curvature were also calculated. Eight insertion experiments were performed. A total of 23 jumps (2.58 ± 2.05 mm) were observed during these insertion processes. When device tip was directed in the same direction as vascular curve, the frequency of tip stop decreased. During the occurrence of a jump, it was observed that the accumulated strain energy was released. However, even when strain energy was accumulated, sometimes no jump occurred. The change in curvature of the guidewire was greater when a large jump (6.89 mm) occurred compared to when a small jump (2.39 mm) occurred. This change was greater at bends with greater vessel curvature. This suggests that surgeons should focus on bends with greater vessel curvature to detect signs of guidewire jumps.

To clarify the relationship between the amount of sample acquired and the method of needle insertion in endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNA), we rapidly punctured a porcine liver with a needle and measured the mass of the sample acquired under -90 kPa negative pressure. The results showed that a puncture speed of 75 mm/s yielded larger amounts compared to 300 mm/s at a needle tip angle of 18°. Additionally, the amount acquired was greater with a needle tip angle of 90° compared to 18° at a puncture speed of 300 mm/s.

With the increase in the elderly population, diseases such as sarcopenia, which result from a decline in muscle mass, have become a significant concern. However, it is challenging to diagnose and treat these conditions in elderly individuals who have difficulty visiting medical facilities. As a result, research is being conducted to develop diagnostic methods that can be performed at home. In this study, we aim to detect the contours of skeletal muscles by using the automatic region extraction algorithm U-Net on video images captured with a portable, small ultrasound diagnostic device. We will then automatically create three-dimensional images of the skeletal muscles. Following this, we aim to establish an evaluation method for muscle mass based on the created three-dimensional images. Using this system, we created a 3D model of the rectus femoris muscle of an adult male and were able to capture the changes in muscle shape from the insertion to the origin.

In recent years, the population aging rate has increased around the world, and the number of bedridden patients with limb impairments is expected to increase in the future. To improve the quality of life of bedridden patients, we have proposed and developed a drone system that can remotely control an 87g drone using only their eyes. However, the drone needs to be controlled using their eyes even when landing the drone at a charging station for recharging. In this paper, we propose a new drone system with a landing assist function added to reduce the operating burden on the patient when landing the 87g drone at a charging station. By using AprilTag attached to the drone and a camera set on the ground, the position of the drone is detected and the drone is guided to land. In addition, we propose two guiding methods to land the drone. Furthermore, we present experimental results to verify the effectiveness of each guiding method.

The authors have proposed a mechanical brake to improve the safety and power consumption of an elbow joint assist suit. The Assist suit with the mechanical brake supports the forearm of the wearer using an actuator when lifting a heavy object. When the wearer continues to hold the lifted weight, the assist suit supports the forearm of the wearer using the mechanical brake. Since the mechanical brake consists of only passive mechanical elements such as springs, it needs no power supply. If the assist suit’s computer malfunctions and the wearer’s elbow joint is moved at an unexpectedly high speed, the suit’s motor is turned off and the assist suit’s movement is stopped by the mechanical brake. Furthermore, the mechanical brake is designed not to resonate with the repetitive flexion and extension motions of the wearer's elbow joint by using the frequency response analysis. However, we have never checked whether the developed mechanical brake resonates with the repetitive flexion and extension motions of the elbow. In this paper, we describe the developed mechanical brake and the elbow joint assist suit with it. Moreover, we present experimental results to check whether the mechanical brake resonates with the repetitive flexion and extension motions of the elbow joint.

The Reynolds-Averaged Navier-Stokes (RANS) framework has long been the standard tool for engineering computational fluid dynamics (CFD). Most RANS turbulence models rely on the eddy viscosity concept, which omits various physical phenomena inherent to the original Reynolds stress transport equations. Directly modeling the transport equation has been a significant topic within the turbulent flow research community and warrants increased attention, even though complex problems can often be addressed by Large Eddy Simulation (LES) or other advanced CFD techniques. This article presents the author's personal perspective on the future direction of transport equation modeling, diverging from the traditional approach that has focused on the pressure-strain rate tensor for decades. Particular attention is paid to the correlation between the instantaneous pressure gradient and velocity, which directly represents the interaction of vortices, an essential process in turbulent fluid motion. Furthermore, the author emphasizes the need for innovative approaches that incorporate a more comprehensive understanding of turbulent structures and their dynamic interactions, suggesting that advancements in computational power and data-driven methodologies will play a crucial role in the evolution of turbulence modeling. This extended view aims to inspire new research avenues that could lead to more accurate and reliable predictive models in engineering applications.

With the aim of proposing concrete countermeasures to the various issues currently facing Japan, such as global warming and securing domestic energy, we conducted a study on the technology and performance of a next-generation electricity/hydrogen co-production system that applies three key technologies: supercritical CO₂ gas turbine power generation technology (GT-NEXT), which uses recycled carbon dioxide for various high-temperature heat sources such as biomass, geothermal, solar heat, and hydrogen-based thermal power, molten salt technology, and radiation chemistry technology. As a result, it was found that in a direct power generation format in which the Generation III bypass-controlled power generation system GT-NEXT is connected to various high-temperature heat sources, including biomass and hydrogen-based thermal power, the power generation efficiency reaches approximately 60%, the world's highest level for a closed cycle, during operation at around 800°C.

Furthermore, with a 1,400°C-class solar heat source, it was demonstrated that it is technically possible to convert the CO generated by high-temperature pyrolysis of supercritical CO₂ (SCO₂) during GT-NEXT power generation into clean hydrogen gas through the water-gas shift reaction (WGS).

The CO₂ recycling technology reported in this paper, which enables highly efficient power generation from various high-temperature heat sources and the simultaneous production of clean hydrogen energy, is expected to make a significant contribution to Japan's measures to prevent global warming and its policy of achieving domestic energy production. Therefore, in today's society where the global environment is being destroyed, there is an urgent need to develop and commercialize key technologies such as supercritical CO₂ gas turbine power generation technology (GT-NEXT).

With the aim of recycling carbon dioxide, the SCO₂ gas turbine power generation technology GT-NEXT, which is indirectly connected to a high-temperature nuclear heat source such as a nuclear fusion reactor or a hightemperature gas reactor via an intermediate heat exchanger (IHX), has a power generation efficiency of 60% during high-temperature operation at 800°C, the world's highest level for closed-cycle power generation.

Furthermore, it is possible to convert CO produced by the SCO₂/CO radiolysis reaction using hightemperature nuclear heat sources and high-level radioactive waste and radiation into clean hydrogen by reacting it with water as a raw material in the water-gas shift reaction (WGS). By combining these core technologies, electricity/hydrogen co-production systems from various high-temperature nuclear heat sources are in sight.

These technologies for producing electricity and hydrogen simultaneously from high-temperature nuclear heat sources are expected to function effectively as a measure to prevent global warming as a fourth industrial revolution technology following steam power generation, which drove the third industrial revolution.

This paper provides a guideline for restoring the high level of Japanese manufacturing technology characterized by quality and efficiency. First, a review of the author's laboratory activities is given. After discussing the monozukuri of learning from failure, the topic of Japanese monozukuri guidelines is presented. The transmission of skills is also discussed.

What is value? How can we know its essence and fulfil it properly? This paper attempts to provide an answer to this fundamental question of society. On the other hand, the concept of design tends to be discussed within the limited field of engineering and manufacturing, even though it is a very widespread and common thought in society, with the aim of satisfying values. The essence of science is to reveal the truth of events and to organise and systematise the results. On the other hand, the production of artifacts that do not exist in nature is different from this, and is done with the idea of design, which acknowledges the possibility of error. In other words, the purpose of design is not to reveal events, but to realise them. As a result, design education in accordance with this meaning is unfortunately neither developed nor provided sufficiently in engineering education, where the emphasis is on science. This is also the reason why the subject of values has been kept away from engineering and avoided. This paper points out the existence of this contradiction and the importance of its solution from an engineering standpoint, and is written in the hope that this discussion will spread throughout society.

In this presentation, our research topics related to reliability of nano and microscale machines are introduced. To evaluate the mechanical properties in micro and nano scale, specimens with excellent quality are needed to be prepared. With a help of microfabrication technologies, we succeeded in fabricating such specimens and measured their excellent mechanical properties of silicon and related materials. However, these works are often destructive, nano and microstructures with very high quality should be destroyed. From these experiences, we have proposed to use fractures to create a new device, which has excellent surface quality to be able to explore physics in nanoscale gaps.

Despite advances in cancer treatment, the mechanisms of metastasis remain largely unknown. We have developed a rapid method to generate millimeter-sized cancer spheroids using a superhydrophobic substrate. In this study, we applied our technique to analyze epithelial-mesenchymal transition (EMT) protein expression in breast cancer spheroids and escaping cells. Three days after formation, we observed increased expression of α-smooth muscle actin, a mesenchymal marker, in cells escaping from spheroids and in escaped cells. Our results suggest that promoting cell escape from spheroids changes the phenotype of cancer cells within a short period of time.

Micropatterning substrates have been pivotal in mechanobiological studies, offering insights into cellular responses to various topologies. Nagashima's group introduced a bio-inspired hierarchical wrinkle patterned substrate, prompting investigation into its effects on cellular behavior and function. In this study, using polydimethylsiloxane (PDMS) substrates with hierarchical wrinkle patterns, undifferentiated human mesenchymal stem cells were cultured for 3 days. Cell attachment and gene expression were evaluated using staining and real-time PCR, respectively. Hierarchical wrinkle patterns induced cellular alignment along the wrinkle pattern, unlike cells on flat surfaces. Moreover, gene expression analysis revealed up-regulation of tenocyte differentiation markers on wrinkle-patterned PDMS, even without differentiation supplements. These findings underscore its potential as a novel approach for directing stem cell fate towards tenocyte lineage without exogenous differentiation agents. Hence, this study sheds light on the significance of topographical cues in regulating stem cell behavior, offering new avenues for tissue engineering and regenerative medicine applications.

Cell behaviors such as morphology, proliferation, and differentiation, are influenced by mechanical strain applied to cells. To study these mechanical responses, cells are often cultured on an elastic membrane and deformed by stretching the membrane. Traditionally, mechanical stimuli involve repetitive stretching and contracting in the same direction. However, in vivo tensile forces can vary in direction. To address this, we developed a "rotational strain field" where the tensile direction rotates. We created a device and a square elastic chamber with an elastic membrane at its bottom to apply this strain field to an osteoblastic cell line MC3T3-E1. Unexpectedly, the cells aligned in the directions parallel to the chamber edges to form a cross pattern, suggesting that the strain field was not uniform. Analysis revealed that the chamber deformed anisotropically, with strains in the direction of the edges being only one-third of those in the diagonal direction, due to lateral bending of the chamber wall. To achieve an isotropic rotational strain field, we redesigned the chamber by adding rigid rods along the edges to prevent the bending. This adjustment resulted in nearly uniform deformation of 8.7% to 9.9% across all directions. When MC3T3-E1 cells were subjected to an isotropic rotational strain field at 60 rpm counterclockwise, they exhibited random orientation, contrasting with the aligned pattern seen under anisotropic conditions. Future research will involve detailed quantitative analysis of cell morphology changes, the effects of rotational direction and speed, and how variations in cell tension influence responses.

Bone remodeling, a process that maintains homeostasis through the activities of osteoclasts and osteoblasts in response to mechanical stimuli, is still not fully understood. This study aims to elucidate a part of this mechanism by establishing osteoblast-like cells derived from the skulls of transgenic mice expressing FRET-based tension sensor, assessing their proliferative and calcification capabilities, and evaluating changes in intracellular tension induced by osteogenic induction medium. Cells were isolated from the calvaria of neonatal FRET mice and passaged in normal medium. A FRET1-MC8 line, which showed superior proliferative capacity, was selected. Calcification capability was evaluated using real-time PCR for bone markers and Alizarin Red S staining. Increased expression of Col1 and Opn under osteogenic condition indicated enhanced differentiation. After two weeks in osteogenic induction medium, calcification was also confirmed via Alizarin Red S staining. Furthermore, intracellular tension changes were monitored by measuring FRET efficiency, which significantly decreased over three days in osteogenic induction medium, indicating an increase in intracellular tension. This cell line expressing the FRET-based tension sensor is expected to contribute to understanding the mechanisms of bone remodeling and to the development of regenerative medicine and treatments for bone diseases.

The development of decellularized organs has attracted attention among regenerative medicine technologies to address the shortage of organs for transplantation. Decellularization is a technique that removes cells from organs while preserving the extracellular matrix. This study focuses on the decellularization process at low-temperature conditions to improve quality and efficiency to investigate the causes of vascular occlusion, specifically through changes in the viscosity of perfusion solutions containing 1% SDS. Using the vascular perfusion decellularization method, we performed a decellularization experiment on kidneys and collected the effluent during the decellularization process to measure the viscosity using a rheometer. The experimental results showed that the pressure inside the vessels increased rapidly during 1% SDS perfusion. Furthermore, effluent viscosity measurements suggest that the 1% SDS solution forms a large number of micelles at low temperatures, which mix with cell debris and cell membranes in the vasculature, increasing viscosity and leading to vascular occlusion.

Zirconia is attracting attention as a biomaterial because of its biocompatibility and mechanical properties. In this study, we focused on the surface roughness and surface geometry of Alumina Toughened Zirconia (ATZ) with approximately 20 mass% alumina, and tried to improve the bioactivity by controlling them. The effects of surface topography on cell differentiation as well as cell adhesion and proliferation were also investigated using Alkaline Phosphatase Assay. Experimental results showed that cell morphology was highly dependent on surface topography. The rate of bone formation increased with surface roughness, whereas there was no difference in calcification between the ground and roughened surfaces. The specimens were autoclaved on the ground and roughened surfaces, and their strength was evaluated in a biaxial bending test.

In the plastic deformation of polymer materials, the necking propagation phenomena is often observed. Considering this deformation machanism from the perspective of mechaniacal strength, the necking area of a specimen should be hardened as compared with non-necking area (=the necking propagation condition). Based on this idea, the aim of this study is to clarify the effect of mechanical strength on necking propagation phenomena for polypropylene material and to identify the cause of softening. The authors conducted tensile tests of thin strip specimens and measured the longitudinal and lateral strains by DIC method. From the result, it was confirmed that the necking propagated through the parallel area of a specimen. At the referenc e point of DIC method where the necking was just propagating, the true stress increased gradually with increasing the true strain. The prediction of mechanical strength derived from this result was consistent with that based on the necking propagation condition. Next, Micro-Vickers hardness measurement for a gauge length was performed to clarify the strength distribution of a specimen. From the measuring results, it was found that the necking propagating area was softer than any other area in the parallel part of the specimen. This result contradicts the necking propagation condition. Therefore, the authors attempted to perform hardness tests while a specimen was kept in tension, and the authors also considered the idea that the yield stress at reloading which was lower than the stress just before unloading caused the contradictions in specimen strength, --- namely, the posibility that Vickers hardness may reflect the mechanical strength at this re-yielding point.

Vehicle ride comfort is constantly being conducted from various perspectives. Knowing the characteristics of seat materials is essential to pursue a comfortable ride. Urethane foam is commonly used in vehicle seats because of its excellent cushioning and durability. Soft materials such as urethane foam have both elastic and viscous properties that vary with frequency and temperature. Dynamic viscoelastic measurements are effective for investigating the vibrational characteristics of such materials. Although there have been many studies on the viscoelastic properties of urethane foam, no prior research has focused on dynamic viscoelastic measurements during compression to simulate the condition of a person sitting on a seat. In this study, dynamic viscoelastic measurements were performed on compressed urethane foam.

The Cold Spray method, in which powder materials are impacted onto a base material below melting temperature and at high velocities, is one of the coating technologies that can form a dense and strong film with relatively little influence of heat or atmosphere. In order to elucidate the film formation mechanism of the Cold Spray method, in this study, we experimentally researched the stress-strain relationships of pure nickel, Inconel 718, and Inconel 600, which are often used in the Cold Spray method. Compression tests are conducted in a wide range of strain rates from quasi-static strain rates (10⁻³/s) to ultra-high strain rates (10⁴/s) to identify the strain rate dependencies of these materials. From the obtained results of these stress-strain relationships, we formulated a constitutive equation that can estimate the stress-strain relationship at any strain rate employed in the Cold Spray method. Since the results of pure nickel and Inconel 718 have already been shown in previous reports, in this study, the results of Inconel 600 are presented.

PF-PC/VGCF is formed by heating at a temperature below the melting point, as in powder metallurgy, to soften only the surface of the base material powder (PC powder) and bond the adjacent base material powders together. In this case, VGCF will exist between the base resin powders. The volume of this bond between base resin powders depends on the molding temperature. By changing the molding temperature, the softened region of the PC powder surface changes, which may change the strength of the composite material. Since VGCF and PC have poor wettability, the bonding strength between PC powders may decrease depending on the molding temperature. In this study, with the aim of clarifying the mechanical properties of PC/VGCF produced by powder compression molding, we clarified the bonding force between PC powders by varying the molding temperature while keeping the amount of VGCF constant. As a result, the bonding strength between PC powders was clarified by changing the molding temperature while keeping the amount of VGCF added constant. The bending strength of PF-PC/VGCF decreased when the forming temperature was low, and increased when the forming temperature was high, and was comparable to PC. Even when the forming temperature changed, the flexural modulus remained almost unchanged. As the local VGCF content of PC/VGCF changes due to changes in molding temperature, it is necessary to mold at an appropriate molding temperature.

The effect of filler addition on the thermal properties of hybrid filler-reinforced polypropylene (PP) composites reinforced with talc fillers and cellulose nanofibers was investigated by numerical analysis. Multiscale finite element analysis based on homogenization theory was performed to clarify the effect of filler content on the thermal properties of PP composites in injection molded materials. Furthermore, a unit cell model of 3D printed heterogeneous structure were constructed, and the effect of thermal deformation suppression was clarified for 3D fused deposition modeling.

The effect of adding cellulose nanofibers (CNF) to piezoelectric filler-dispersed polymer-based composite materials, that is expected to be used in flexible and printable devices, was investigated. Barium titanate particles were used as the piezoelectric filler and polypropylene was used as the matrix, and test specimens were produced through mold forming. It was found that the addition of CNF changed the elastic modulus, dielectric constant, and piezoelectric properties of the matrix, and that at a certain piezoelectric filler content, the piezoelectric properties of composites improved by more than 50%.

The mechanical properties of cellulose fiber-reinforced polymer composites with reversible cross-linking were investigated atomistically as matrix that simultaneously satisfies the two properties of sustainability and toughness. 2-hydroxypropyl acrylate and 2-methoxyethyl acrylate were employed as the primary and secondary polymers， respectively. Citrate-acid modified cellulose (CAC) was used as the reinforcing fiber, and reversible crosslinking with β-cyclodextrin as the host molecule and adamantane as the guest molecule was introduced to toughen the matrix. First-principles calculations based on density functional theory were used to analyze the bonding forces between the constituent molecules in the CAC composite. First-principles calculations provided atomistically consistent explanations of the experimental results and elucidated the strengthening mechanism of the CAC composites.

Titanium is known as a relatively lightweight metal with high corrosion resistance. It also exhibits high corrosion resistance to seawater, which is superior to other major corrosion-resistant metals. According to the JIS standards, materials are divided into 1, 2, 3, and 4 class types depending on their impurity content. The JIS 2 class type materials are widely used because they have a good balance between strength and workability. Products formed by plastic working are often subjected to processing that involves minute deformation or heat treatment. Materials that have been work-hardened through plastic working such as forging or rolling are subjected to heat treatment to remove internal strain. In other words, the work-hardened metal structure is improved while maintaining the plastic deformation caused by plastic working. However, there are few studies investigating the effects of microfabrication heat treatments with different processing histories on pure titanium. In the present study, heat treatment was performed on pure titanium that had been subjected to micro-deformation by rolling and tensile deformation, and the effect of thermomechanical treatment on tensile properties was investigated. Test material was JIS 2 class type and has a thickness of 1 mm. The shape of the workpiece was half size of JIS13B. The tensile speed was 1 mm/min. A rolling mill with a roll diameter of 50 mm was used for rolling. It was found that heat treatment after micro-deformation by rolling improves elongation at break.

The disposal of resin materials places a heavy burden on the natural environment. It is therefore necessary to improve the accuracy of strength design methods in order to minimize the amount of resin materials used. It is essential to accurately estimate the stress-strain relationship at arbitrary strain rates and temperatures. Methods for predicting the stress-strain relationship of plastic materials at arbitrary combinations of strain rate and temperature have not been sufficiently investigated. Therefore, we conducted tensile tests at room and elevated temperatures to clarify the effects of temperature and strain rate on Young's modulus and flow stress. Tensile tests showed that flow stress decreased with increasing strain rate and with increasing temperature. Young's modulus increased with increasing strain rate and decreased with increasing test temperature. Compared to the Young's modulus of PC, the Young's modulus of POM is slightly larger, and the strain rate dependence is more sensitive for POM than for PC.

The strengthening mechanism of electrodeposited nanocrystalline (nc) iron (Fe) – nickel (Ni) alloy by multilayering in which Ni-rich and Fe-rich alloy layers were alternately stacked was investigated, to obtain a electrodeposition process of high strength and ductile nc materials. The electrodeposition was conducted using a sequence-controlled DC power supply. The multilayer Fe-Ni alloys having layers from 3 - 75 were produced and their tensile property was compared to the monolayer Fe and Ni. The strength and elongation of nanocrystalline Fe-Ni alloy increase with increasing number of layers. multilayer Fe-Ni alloy with 51 layers shows the maximum values of the ultimate tensile strength and elongation of 2.1 GPa and 12.5 %, respectively.

Effect of grain boundary character distribution (GBCD) on the tensile property in SUS430 ferritic stainless steel was investigated using grain boundary engineered (GBEed) specimen with high fraction of low-energy grain boundaries, especially low-angle GBs in comparison with commercially-available 409L. The control of GB microstructure was carried out by cold rolling of 88 % and subsequent annealing at 973 K for 600 s. The GBEed specimens possessed the texture oriented to {001} – {111} and high fraction of low-angle GBs of more than 30 %. The GBEed specimens showed the higher tensile strength and larger elongation than as-received (non-GBEed) materials.

The purpose of this study is to establish a process to control the multilayer and stacking ratio of nanocrystalline Fe-Ni alloys, and to investigate the effect of stacking ratio on tensile properties of multilayered nanocrystalline Fe-Ni alloys. For the electrodeposition of multilayer nanocrystalline Fe-Ni alloys, an electrodeposition bath with ferric chloride and nickel sulfamate as the main components was used. In the multilayering process, Fe and Ni layers were electrodeposited alternatively at predetermined deposition times based on the deposition ratio of both layers. Fe layer was formed at a constant voltage of 3.4V, while Ni layer was formed using pulse-wave form voltages ranging from 3.0 to 3.8V. The Fe/Ni multilayered alloys possessing different stacking ratio from Fe : Ni = 1 : 9 to 9 : 1were obtained. The maximum ultimate tensile strength of 1.53 GPa and the muximum plastic elongation of 8 % were obtained when the stacking ratio of Fe and Ni layers was 7 : 3.

Nickel-based superalloys used in gas turbine disks are required to operate under frequent and random fluctuations in power output at elevated temperatures. Under such high-temperature creep-fatigue loading conditions, the crystallinity near grain boundaries deteriorates rapidly, and intergranular cracking occurs, significantly reducing material life. In this study, the acceleration mechanism of intergranular cracking observed in GH4169, which is one of the typical nickel-based alloys for jet engines, was investigated using molecular dynamics. At temperatures above 650°C, the γ"(Ni₃Nb) phase of the dispersion strengthened precipitation structure coarsens, and the more stable δ(Ni₃Nb) phase precipitates mainly in needle-like form near the grain boundary. In MD (Molecular Dynamics) simulations modeling the δ-phase precipitated near the grain boundary of the nickel matrix, the formation of a local stress concentration field near the interface between the δ-phase precipitates and the nickel matrix under creep loading induced the generation of dislocations between the precipitates and the unstable grain boundary. A large lattice mismatch at the interface between the δ-phase and the nickel matrix causes the formation of this stress concentration field. The stress concentration field at the interface between the δ-phase adjacent to a grain boundary and the matrix phase increased the instability of the grain boundary, accelerating the degradation of crystallinity near the grain boundary and deteriorating the grain boundary strength.

Effect of multilayering of nanocrystalline Fe-Ni alloys with different Ni compositions on tensile strength and ductility was investigated to obtain a clue to development of nanocrystalline material with high ductility. Pulse-electrodeposition using an electrolyte mainly composed of ferric chloride and nickel sulfamate was employed to produce multilayer nanocrystalline Fe-Ni alloy with different number of layers. The ultimate tensile strength (UTS) and elongation increased with increasing number of layers in the range of less than 155 layers. The multilayer nanocrystalline Fe-Ni alloy possessing 155 layers showed the maximum values of UTS of 2.63 GPa and elongation of 6 %

Nuclear power plants promise to play an essential role in achieving carbon neutrality. Under such circumstances, the Generation IV reactor currently under development uses liquid sodium as the coolant, and the operating temperature is 550°C, surpassing that of conventional reactors. Stainless steel SUS316LN, known for its high corrosion resistance to liquid sodium, is a potential material for the pressure vessel and piping in this reactor. However, the accelerated formation and accumulation of voids and dislocations around grain boundaries in elevated-temperature creep-loading conditions lead to significant deterioration of fracture life due to intergranular cracking. In this study, elevated-temperature creep tests of stainless steel SUS316LN were conducted to investigate the grain boundary damage process. The degradation process around grain boundaries was then evaluated using KAM (Kernel Average Misorientation) values obtained from EBSD analysis. The KAM values around the grain boundary increased monotonically with increasing loading time and test temperature, confirming the damage accumulation process around grain boundaries. The activation energy of the increase in KAM values caused by creep loading was evaluated using an Arrhenius plot, and the increase in KAM values was quantitatively explained by a modified Arrhenius equation that considers the stress-induced change in the activation energy of Fe atom diffusion. Therefore, the formation and accumulation processes of voids around grain boundaries under creep loading can be evaluated based on the atomic diffusion accelerated by the local strain field around grain boundaries caused by the superposition of a loading stress and lattice mismatch between grains.

Aluminum has been used in automobiles because of its light weight and high specific strength. Tribological technology is important for improving the efficiency and evaluating the life of these materials, and it is essential to understand the contact behavior between solids. In this study, pressure tests were conducted using two small blocks made of pure aluminum with smooth contact surfaces, and the changes in the contact surface properties before and after the tests were measured. Moreover, the relationship between the Schmid factor difference and the change in the height distribution on the contact surface before and after the test was also investigated. Although surface height distribution after the pressure test could be predicted from Schmid factor difference evaluated based on the crystal orientations of grains facing to each other, the effect of neighboring grains was not negligible.

Bulk metallic glasses exhibit viscous flowability in the supercooled liquid state. Bulk metallic glasses transitions to a supercooled liquid state between glass transition temperature T_g and crystallization temperature T_x. AuCuAgSi bulk metallic glasses is known to have T_g below 373 K (100 °C), which is extremely low compared to other bulk metallic glasses. For the purpose of decreasing T_g and increasing stability, AuCuAgSiGe bulk metallic glass was developed. The stability and the viscosity in the supercooled liquid state were evaluated.

Low-cycle fatigue tests and X-ray diffraction measurements were carried out using uncharged and hydrogen-charged specimens of austenitic stainless steel JIS-SUS316 in order to investigate effects of hydrogen on strain induced martensitic transformation in low-cycle fatigue tests. The specimens were polished with buff and introduced small artificial holes whose diameter was 100 μm and 300 μm. Low-cycle fatigue tests were carried out up to 100 cycles under reversed torsional loading and circular loading. The strain range was 1 %. After the fatigue tests, X-ray diffraction measurements were conducted in order to investigate the amount of martensitic phase. The experimental results showed that the equivalent stress range of the hydrogen-charged specimens increased, compared to the uncharged specimens. Hydrogen may have been promoted cyclic hardening. The amount of martensite of the uncharged and hydrogen-charged specimens increased in fatigue tests when the amount of martensite before the tests was less than 11 %. On the other hand, the amount of martensite of the uncharged and hydrogen-charged specimens decreased in fatigue tests when the amount of martensite before the tests was more than 11 %. The cause may be that surface polishing affected on strain-induced martensitic transformation. Therefore, it is necessary to consider the possibility that residual stress due to surface polishing may have affected the amount of martensite.

In order to investigate effects of hydrogen on strain-induced martensitic transformation of austenitic stainless steel JIS-SUS316L in tensile tests, the relationship between plastic strain and the amount of strain-induced martensitic was measured using hydrogen-charged and uncharged specimens by X-ray diffraction analysis. The experimental result of the quantitative analysis by the RIR method showed that 0 % pre-strained hydrogen-charged specimen had more martensite than 0 % pre-strained uncharged within plastic strain 5 %. However, the 0 % pre-strained uncharged specimens had more martensite than 0 % pre-strained hydrogen-charged for ε_p=5 %～60.4 %.10 % pre-strained uncharged specimen had more martensite than 10 % pre-strained hydrogen-charged specimen. The X-ray profiles show that the martensitic α' (110) and ε(101) peaks of 0 % pre-strained hydrogen-charged specimen were stronger than those of 0 % pre-strained uncharged specimen. The austenite γ(200) peak of 10 % pre-strained hydrogen-charged specimen was significantly strong.

This study concerns an anomaly identification method that uses CNN classification of bridge vibration spectrogram images. A spectrogram displays both frequency and time characteristics in a single image. Damage to a bridge has different effects on vibration depending on the type. The effects of the occurrence of damage occur in frequency characteristics and damping characteristics. In this paper, the influence of the characteristic frequencies and time components of bridge vibrations shown in the spectrogram on the identification accuracy is considered, and a method for creating a spectrogram that effectively improves accuracy is clarified.

Recently, the demand for WPCs (wood plastic composites) an alternative to plastic technology has been increasing exponentially since its utility was recognized. On the other hand, CNF (cellulose nanofiber) is currently on the rise as one of the leading reinforcing fibers for resin matrix composites, which is a nanocellulose extracted physically or chemically from microfibrils of woody or herbaceous plants. Although it is lightweight, the tensile strength exceeds 3GPa, making it extremely tough. CNF is also a sustainable material because of its biodegradability, and therefore the addition of CNF to WPC is expected to replace carbon and glass fibers, which are the mainstream reinforcing fibers.

The purpose of this study is thus to produce a thin WPC (wood plastic composite) film reinforced with CNF and to evaluate its mechanical properties. Tensile test results show that values close to 40 MPa can be obtained by selecting the appropriate production temperature.

The operating temperature of aircraft jet engines has been increased to improve thermal efficiency for addressing global warming by reducing greenhouse gas emissions. The Ni-based superalloy GH4169 (IN718) is used in aircraft components because of its high-temperature strength, fracture toughness, and oxidation resistance. In GH4169, which has a higher Nb content (about five mass%) than other nickel-base alloys, the γ"(Ni₃Nb) phase coarsens at temperatures above 650°C and precipitates as the more stable δ-phase in needle-like form near grain boundaries. Under high-temperature creep loading, fine voids accumulate near the interface between the δ-phase precipitated around grain boundaries and the matrix phase and accelerate intergranular cracking, indicating that the effect of δ-phase precipitates on creep damage evolution should be considered when this alloy is used in a high-temperature condition. In this study, intermittent creep tests were conducted around 800°C on GH4169. Scanning electron microscopy (SEM) observations were performed on the interrupted creep specimens to quantitatively evaluate the δ phase content and the temperature and stress dependence of the precipitation rate.

There have been many studies on low-cycle fatigue of steel under axial loading, such as quantitative studies on small crack propagation and studies on the effect of grain size on fatigue strength. However, in the case of low-cycle fatigue of steel in torsion, there are not many studies that quantitatively evaluates crack propagation and examines the effect of grain size, although there are some studies that continuously observe crack initiation and propagation. In this study, cyclic torsional low-cycle fatigue tests were performed on S10C specimens with different grain sizes, and the effect of grain size on small crack propagation and the validity of the small crack propagation law in torsional low-cycle fatigue were investigated, focusing on cracks with lengths up to 1 mm. Fatigue tests were conducted in a torsion testing machine (490 Nm capacity) at room temperature in air and controlled torsional angle for a given total strain range. Cracks were observed using the replica method, and replicas of the specimen surface were taken at regular intervals in each total strain range and observed with an optical microscope. The results showed that the small crack propagation law was established in torsional low-cycle fatigue, and that the larger the grain size, the shorter the crack propagation life.

The metal engraving technique "KEBORI" as the traditional arts and crafts was reproduced using the latest machining technology with a 6-axis control machining center. In the machining center, the 6th axis control for rotation control of the spindle was installed on a 5-axis machining center. In the previous study, the authors investigated the possibility of processing engraving patterns on a curved surface, which was thought to require more complicated axes control for the machining center. In this paper, machining errors were examined and their factors were analyzed in terms of the motion behavior of each axis.

Currently, drones are capable of beyond visual line-of-sight (BVLOS) operations in populated areas, requiring more advanced piloting skills. This study aims to elucidate the techniques of experienced pilots in both visual line-of-sight (VLOS) and BVLOS operations using a ladder navigation task. The participants included seven certified pilots and six beginners. The movements of the DJI drone were tracked using the MAC 3D SYSTEM (Motion Analysis) optical motion capture system. The results showed that experienced pilots could fly the drone in a similar amount of time across tasks. Additionally, the flight paths of less experienced pilots tended to be more linear.

Magnesium is a lightweight material among practical metals and has a lower density than other metals. In addition, the alloy has several attractive properties such as high strength-to-weight ratio, good machinability, good electromagnetic shielding properties, and recyclability. However, most magnesium alloys require improved corrosion and wear resistance. In the present study, the joining of magnesium alloys to dissimilar metal foils by shot peening was investigated to improve surface properties. In the experimental method, several types of magnesium alloys were commercially available extruded round bars. The alloy type was AZX611, and the metal foils were pure titanium. Shot peening was performed on a centrifugal shot peening machine. The shot media was cast steel with an average diameter of 1.0 mm. The peening velocity and peening time were 60 m/s and 10 s, respectively. The substrate and metal foils were heated at 300 oC and 350 oC. After joining, no voids or cracks were observed at the joining interface. In bending test, the metal foil did not peel off even when the substrate was broken. In addition, the bondability of dissimilar metal foils was improved by heat treatment at 450 °C. This method was effective for surface modification of magnesium alloys.