Detection of cancer cells is important for cancer diagnosis, and it is necessary to distinguish the cancer cells from healthy cells. The cancer cells can be characterized by electric properties, especially membrane permittivity and cytoplasm conductivity. An electrorotation (ROT) technique is often employed to analyze these properties, but the number of measured data in a single device sometimes becomes an issue. In this study, ROT device with orthogonal rotation axis was developed for measuring electric properties of multiple flowing cancer cells in the device by devising the location of the electrodes. In measurement of HeLa and A549 cells, their electric properties were obtained with high throughput and differences of the properties between these cells could be verified.

Infectious diseases are a problem in all departments in the medical field. Therefore, an attempt was made to develop antimicrobial medical materials. Methods reported so far for creating antimicrobial metal surfaces include coating with polymers, blending or covering with antimicrobial silver and laser machining to generate micro-textures to improve water repellency and resistance to biofouling. However, these methods have many problems for practical application in the medical field, such as insufficient antimicrobial resistance and high costs, and there are still issues to be solved.

In this study, microtexture creation by metal fatigue, which is an inexpensive method, was successfully achieved. Antimicrobial properties were confirmed on metal surfaces that were found to be water-repellent.

This study aimed to develop a device for measuring the elastic modulus distribution within collagen gels simultaneously. The device utilized magnetic particles mixed within the gel and measured their displacement using a magnetic field. The experimental setup was constructed on a microscope stage, allowing simultaneous measurement of multiple magnetic particles' displacements. The magnetic susceptibility of the particles was determined using fluid samples of different viscosities. The collagen gels were prepared by mixing collagen solution, concentrated medium, NaOH, and phosphate-buffered saline. The developed device successfully generated magnetic forces and observed the displacement of magnetic particles within the collagen gels. The results provided the volume magnetic susceptibility of the particles and the microviscosity of the gels. This device holds potential for obtaining three-dimensional displacement distributions and acquiring the elastic modulus distribution within collagen gels.

This study aimed to evaluate the effect of the surface modification ratio (the area fraction of the HAp surface modified by the modification polymers) on the hydrolysis properties of HAp/PLA composites. Here, the negatively charged sodium alginate and positively charged chitosan were adsorbed to the positive and negative charge of the HAps, respectively. The surface modification ratio was adjusted to 100 [%], 75 [%], and 50 [%] for the preparation of the hybrid-interface-controlled HAp/PLA. The hybrid-interface-controlled HAp/PLA specimens were hydrolyzed by immersing into the simulated in-vivo conditions for 0, 1, 2, and 4[weeks], and were then subjected to tensile tests. In the case of hybrid-interface-controlled HAp/PLA with the sodium alginate and the chitosan, the tensile strength increased with increasing the surface modification ratio. The decrease in tensile strength due to hydrolysis was the most suppressed under the condition where the surface modification ratio was 100 [%]. This suggests that the optimal design of the molecular structure for the hybrid-interface-control using the sodium alginate and the chitosan could be achieved at a surface modification ratio of 100[%].

In recent years, it has become clear that exercise produces a variety of bioactive substances, called myokines, that help maintain healthy body functions. However, myokines are difficult to assess unambiguously because they are influenced by other hormones. Therefore, in this study, we established a simple in vitro experimental system for myokine research. In this experimental system, artificial skeletal muscle is cultured in different stretching patterns. By changing the structure of the skeletal muscle and the culture medium, we can study the effects of muscle movement patterns on myokine production. Our research group has succeeded in producing artificial skeletal muscle that simulates human muscle from mouse muscle cells. We have designed and developed a culture system to apply different stretch stimuli to the artificial skeletal muscle. Our goal is to quantitatively evaluate the relationship between the amount of myokine secretion and the muscle movement pattern by applying different stretching stimulus patterns to the artificial muscle and investigating the effects on the amount of myokine secretion.

A notched stress concentration part was provided in aluminum alloy A5052 round bar test piece, tensile stress and strain was applied to the bottom. The changing nonlinear acoustic characterization due to strain generated at the bottom of the notch were investigated using Axial-shear-wave EMAT (electromagnetic acoustic resonance), which transmits and receives SH wave propagating in the circumferential direction of a test piece specimen was used. The harmonic components nonlinearity was rapidly increased with tensile stress. The FEM (finite element method) analysis indicates that the increase of strain caused in the stress concentration area corresponds to the change in the harmonic nonlinear. This method may be potentially to capture the microstructural changes in metal materials that occur in the stress concentration area.

In this paper, a tensile test of single carbon fiber composites was conducted and AE (Acoustic emissions) by fiber breakage were recorded. Two AE sensors were used for detecting AE waveforms to estimate location of the AE source. The location of fiber breakage was also confirmed by polarized visual observation using a video microscope. From the comparison of AE source location and fiber breakage location, it was found that AE occurred in this specimen caused by fiber breakage. The time-frequency analysis using Wavelet transform showed that the fiber breakage AE had two components: one was AE by fiber breakage in a range of 280-400 kHz and another was AE by pull-out in a range of 700-900kHz. The results also showed that it was difficult to detect the high frequency component of pull-out due to attenuation of wave. As for this specimen, it appeared that most of AE waves by fiber breakage involved pull-out component. The duration time had no correlation with loading strain, however the amplitude had positive correlation because the AE power governed by released strain energy at fiber breakage.

This paper proposes a periodic tube-block structure and investigates its application for controlling elastic wave propagation. The elastic wave transmission and resonance in the structure were analyzed by the finite element method. As a result, it was shown that the transmission ratio has many peaks at different frequencies depending on the dimensions of the structure, such as the tube radius. These peaks are associated with local resonance in the structure. Some of them result from tube resonance, and their peak frequencies shift when the outer radius and thickness of the tube are changed. Other peaks appear due to local resonance in the vicinity of the block surfaces, and their peak frequencies vary with the width between tubes. The effect of the joint width between tube and block on the peak behavior is relatively insignificant.

Damage in CFRP has been classified mainly based on frequency-domain features of the waveform using the AE method. On the other hand, AE waves in a CFRP plate propagate as Lamb waves and attenuate and scatter as they propagate. The attenuation and scattering depend on the mode of Lamb waves, frequency, and propagation direction. Therefore, features of AE waveforms change due to attenuation and scattering, making it difficult to classify fracture modes. In this study, the dependence of the attenuation on the frequency, and propagation direction for symmetric and anti-symmetric modes of Lamb waves in a unidirectional CFRP plate was measured to compensate frequency spectra of Lamb waves at different propagation lengths. It was confirmed that the anti-symmetric(A) mode Lamb wave has larger attenuation than the symmetric(S) mode, and the S-mode Lamb wave has a stronger dependence on the propagation direction than the A-mode. Based on the measured attenuation coefficients, we attempted to compensate for the frequency spectra of the waveforms detected by two piezoelectric-type AE sensors with different diameters. The compensation could be performed for the small sensor only.

The wall thickness was measured using the laser ultrasonic method. The results from the finite element analysis show that the ultrasonic waves propagate parallel to the slope of the groove and therefore underestimate the thickness as they approach the apex. In the thermoelastic regime, the second reflection of longitudinal wave is not measured because the transverse wave is stronger than the longitudinal wave, and the first transverse wave is measured at that time. Therefore, if thickness measurements are made using the second reflection of longitudinal wave in ablation, an overestimation occurs, but if thickness measurements are made in the thermoelastic mode, no overestimation occurs.

Photoacoustic microscope makes it possible to observe microstructures and defects of the sample by utilizing the diffraction and reflection phenomena of thermal waves and elastic waves, which have different wave properties. However, the heat conduction equation based on classical Fourier’s law could not reproduce the propagation behavior of the heat wave. Therefore, our group has attempted numerical simulations of thermal and elastic waves using non-Fourier heat conduction equations with time-delay terms and the finite difference time domain method. In this presentation, we report the results of numerical simulation of thermal and elastic waves propagating in three-dimensional space which is including defects.

CFRP is a promising material in various industrial field due to its high specific strength. The interlaminar strength between layers in the CFRP is also important. In this study, the interlaminar strength of CFRP was evaluated with a laser spallation technique. The laser spallation technique allows to exfoliate the interface between the layers by strong longitudinal waves induced by a pulsed laser irradiation. Two cross-ply CFRP plates fabricated with different molding pressure of 0.1MPa (normal) and 0.01 MPa and fiber volume fraction (V_f) of 67% and a unidirectional CFRP with low V_f of 45% were prepared. The interlaminar strength of the low V_f sample was decreased by 20 MPa compared to that of the normal CFRP. The decrease in interlaminar strength was caused by the thicker resin rich area along the interfaces in low fiber volume fraction. On the other hand, the strength of the CFRP molded with the low pressure was the same as that with normal pressure.

In recent years, the demand for higher temperature and higher efficiency in high-temperature equipment such as jet engines and gas turbines has led to the research and development of heat-resistant steels and Ni-based superalloys, which have greatly improved heat resistance. Ti-Al alloys have been attracting attention as advanced heat-resistant materials for further improvement of efficiency and weight reduction. In this study, this research aims to elucidate the creep properties of a wrought Ti-Al alloy, Ti-43Al-5V-4Nb with a triplex microstructure. Nonlinear ultrasonic properties of creep specimens of Ti-Al alloys are measured using electromagnetic ultrasonic resonance and the changes of ultrasonic properties with the progress of creep damage are investigated.

The oxide scale formed on low carbon steel during hot rolling process is removed with high pressure water jets in its production process. Some researchers reported that the adhesive strength of the oxide scale was depended on structure of the scale and chemical composition in a substrate. However, the adhesive strength is still unclear. In this study, the effect of Cu addition and heat-treatment processes on adhesive strength of the oxide scale on carbon steel was estimated with a laser spallation technique. Estimated adhesive strength of the scale treated by reheating at 380 oC for phase change of the scale after 700 oC to form a scale were around 40 to 50 MPa. The strength of the samples including Cu content of 1 % with reheating process were higher than those without reheating. Whereas the adhesive strength tended to decrease with increasing Cu content and decreased to about 30 to 45MPa at Cu content of 3 to 5 % for all heat-treatment due to Cu precipitation as a layer along the scale/substrate interface.

Crack growth behaviors in pre-cracked elliptical specimens subjected to thermal shock were characterized using Disc-on-Rod tests developed by the authors. The central area of heated specimen was quenched by means of contacting with a cool copper rod. Crack growth with various Mode I/Mode II ratio was obtained by changing the crack angle. The crack path was recorded during tests and introduced into the finite element model. Measured temperature distribution was inserted into the model and thermal stress field was calculated. Fracture mechanical parameters during thermal shock crack growth were then determined using a virtual crack closure method. It was demonstrated that the macroscopically stable crack growth consists of intermittent crack growth with small scale unstable crack and crack arrest. It was also found that crack growth resistance were increased with the crack length. It is worth noting that the larger the grain size was the higher the crack growth resistance was. Consequently, the experimental technique to characterize the fracture mechanical behavior of thermal shock crack was developed in the present study.

The mechanical reliability of products must be assured for scaling up and production of complex-shaped components by spark plasma sintering (SPS) of spray-dried granules. The evolution of morphologies of pores and defects, which control the mechanical strength, is investigated by using synchrotron X-ray multiscale tomography during SPS of alumina granules at 1300 °C. While large defects arising from the hierarchical granule packing structure cannot be removed by pressureless sintering, crack-like defects and branched rodlike defects are almost eliminated by SPS at stresses higher than 30 and 50 MPa, respectively. But, small ellipsoidal porous regions, which may arise from aggregates or dimples of granules, cannot be removed even at a pressure of 50 MPa. A very large defect is also found by using micro-CT. It is supposed that this defect is formed from a large void in loosely packed granules. The shrinkage of large voids and the elimination of crack-like defects are explained by the theoretical prediction based on the continuum theory of sintering.

In the present study, we performed three-dimensional observation and analysis of strain distribution for all-oxide ceramic matrix composite (CMC) using X-ray computed tomography (X-CT) and digital volume correlation technique (DVC). For testing, uni-directionally (UD) reinforced oxide matrix CMC was used for model material. Mechanical properties of the composites fabricated under two different conditions were characterized. Damage evolution during loading was successfully visualized by volumetric image and image analysis combined with deep learning. The results revealed that interlaminar failure occurs during loading. The results of strain distribution is in good agreement with 3D observation.

Metamaterials can develop new properties by controlling their shape. The structure imitating Menger sponge, the self-similar form, has the property that the stress concentration area changes depending on the complexity of the structure. These properties are potentially applicable as metamaterials to control the damage initiation area. In this study, structures imitating H-shaped fractals and Sierpinski gaskets were fabricated, and their stress concentration characteristics were investigated with experiment and finite element method. Artificial design was needed because the original self-similar forms of H-shaped fractal and Sierpinski gasket have areas of zero length or thickness. In the case of Sierpinski gasket, the stress concentration area did not change within the design of this study, however, in the case of H-shaped fractals, the property of changing the stress concentration area was observed when the structures were designed so that the similarity was maintained.

In order to obtain a material having the high-temperature strength, wear resistance and damping capacity, the preforms of VGCF adhered to the surface of short alumina fibers were prepared and infiltrated with molten aluminum alloy using the squeeze casting. The volume fraction of alumina fiber was 15 vol% and that of VGCF was varied from 0~9 vol%. Optical and electron microscopy, wear test under dry sliding conditions and damping tests were carried out. Although there was no agglomeration of the VGCF in the composite when the volume fraction of VGCF was 3 vol%, agglomeration was observed when 6 and more volume percent of VGCF was added. The hardness of the composite with 9 vol% VGCF was smaller than the unreinforced alloy, but that with 3 and 6 vol% VGCF was equivalent to that of the unreinforced alloy. While there was no clear improvement in wear resistance due to the reinforcements under low-sliding velocity, the wear loss of the composites was significantly lower than that of the unreinforced alloy under high-sliding velocity.

Since the boiling heat transfer is much affected by the nucleation of bubble and its growth, estimation of such process is essential for the accurate prediction of the heat transfer. Practical solid surface has surface roughness unlike ideal conditions, and nanostructure on solid surface much affects the contact line motion. In this study, molecular dynamics simulation was performed in order to study the effect of the nanostructure on the bubble growth. In this simulation, the pillars were applied to the wall surface periodically and pillar height and we investigated the effect of pillar width and height. The simulation results show that the pinning of contact line to the pillar edge increases apparent contact angle, and the depinning of contact line occurs in two different forms. The first is due to the approach of liquid-gas interface and the pillar edge, where the apparent contact angle decreases to the minimum value. The second is due to the decrease in density in the dent near the contact line, where the apparent contact angle does not decrease to a minimum value and has no fixed value.

In this study, thermal induced flow around a set of rectangular blocks modeled from stepped Al-Ga-As / Ga-As-Si semiconductors set in a microchannel is simulated by solving the Navier-Stokes equation with velocity slip and temperature jump conditions on the wall. The surface temperature on one side of each rectangular block was set higher than that on the other. The simulation results suggest that the pressure increases from low temperature surface to high temperature surface of rectangular blocks stepwise and that the computational model plays the role of a pump by generating thermal induced flow around each block.

In recent years, there has been an increasing number of reports employing the highly efficient photothermal conversion phenomenon known as "plasmonic heating," driven by metallic nanoparticles, as a driving force for optofluidic transport in the micro/nanoscale regime. Plasmonic heating refers to the phenomenon where noble metal nanoparticles with diameters ranging from 5 to 200 nm exhibit extremely efficient light absorption and subsequent heat generation due to the "localized surface plasmon resonance" effect, acting as optical antennas at the nanometer scale. In this presentation, we discuss the application of "plasmonic heating" and its potential in effectively controlling the temperature distribution in nanospaces, particularly focusing on the influence of incident light wavelength and polarization. Specifically, we have obtained numerical solutions by employing the finite element method to solve the Maxwell's equations and the steadystate heat conduction equation. The results reveal the significance of using titanium nitride as a plasmonic material, which possesses superior thermal properties compared to the commonly employed gold, for achieving enhanced plasmonic heating effects.

Desalination technology to obtain fresh water from seawater is currently attracting attention as a solution to the world's water shortages. This study focuses on membrane distillation (MD) utilizing separation membranes, especially direct contact membrane distillation (DCMD). The authors have succeeded in developing a prototype DCMD system and in desalination from 1 wt% brine. In this study, desalination experiments from brine of 3 wt%, a concentration like actual seawater, were conducted, and a theoretical model was used to compare and evaluate the water permeation fluxes. The properties of the membranes used in the experiments were also investigated in combination with the experiments. As a result, 3 wt% brine was successfully desalinated, although the permeation flux was reduced compared to 1 wt% brine. The membranes used in the experiments had uniformly distributed pores with uniform diameters. Therefore, it was inferred that this membrane is suitable for seawater desalination in terms of pore size distribution, although it may not be hydrophobic enough.

In recent years, microfluidic devices have attracted attention in various fields of research. However, its gas permeability is subject to external heating and chemical reaction heat. This leads to bubble formation and blockage of microfluidic channels. We focused on microfluidic devices using polymethyl methacrylate (PMMA), which has high light permeability and gas tightness among polymer resins. We have applied the diffusion bonding technique, which is mainly used for bonding homogeneous metals, to polymer resins and have succeeded in bonding two base materials without deformation. The best maximum temperature for bonding was found to be 100°C. It was also confirmed that the smoothness of the bonding surface has a significant effect on the bonding results. This research aims to mass-produce flexible microfluidic devices using polymethyl methacrylate (PMMA) film. methacrylate (PMMA), which has good light permeability and gas-tightness, for use as heat exchangers, and to establish diffusion bonding as a sealing technology for these devices.

In our laboratory, the self-running mechanism of Leidenfrost-state droplets on a substrate with a sawteeth have been investigated, for the purpose of developing a new power source. In this presentation, the modification of the experimental system will be introduced. And consideration of the mechanism by which the thermal energy supplied to the droplets from the substrate drives the droplet, as described below, will be reported. First, it is assumed that the velocity of the droplet running on the sawteeth substrate becomes constant because the shear stress exerted by the vapor on the bottom surface of the droplets is balanced with the air resistance acting on the front surface of the droplet in the traveling direction, and the velocity (ut) of the vapor that blows off the surface of the droplet in the direction of travel of the droplet was obtained. Comparing with the vapor velocity (us) ejected from the stationary Leidenfrost state droplet surface on a flat substrate, it was found that ut is only about 1% of us at most. In other words, it was found that most of the steam spewed out in a direction that had nothing to do with the direction in which the droplet traveled.

Most study of molecular dynamics (MD) simulation on deformation of amorphous alloy have been performed on a viewpoint of plastic deformation of solid. They lack a viewpoint of liquid, namely viscosity. In present study, to clarify both viewpoints, the shear deformation of Zr₅₀Cu₅₀ amorphous alloy is simulated by molecular dynamics method. The shear strain rate is from 0.125 to 4.000 /ns. Thermodynamic quantities, viscosity, shear stress and rigidity are analyzed from simulated data.

At high pressure and temperatures over the critical point, the fluid is in the state of supercritical fluid. In the conventional fluid dtnamics, the fluid is described as continuum. In atom order, the fluid is discrete. In recent years, the MEMS has been developed. In the future, it is expected that nanomachines in the true sense of the term will be put to practical use. In present study, the flow of supercritical Ar at Re 200 around a prismatic object is simulated by molecular dynamics (MD) method with LJ potential. The flow is analyzed in atom or boxel level to obtain the insight into the supercritical fluids in the nanoscale order.

The dynamic contact angle and the interface geometry of ethylene glycol droplet is analyzed by molecular dynamics, in which the ethylene glycol droplet is sheared between two parallel plates with self-assembled monolayers (SAM). The contact angle is increased with the contact line velocity for the case liquid is advancing on the SAM surface. The proportional constant between the shear stress on the interface between ethylene glycol and SAM was also investigated, showing that the proportional constant decrease with the shear rate.

This study proposes a new method for generating silicon substrates with a thickness of less than 100 μm using surface tension and electromagnetic pressure. The authors had previously conducted experiments to generate substrates by applying electromagnetic pressure, but the thickness did not reach the target of 100 μm. In order to solve the problem for the thickness reduction, the shape of the crucible was changed in the substrate generation experiments, and the thickness was successfully reduced to less than 100 μm in some region of the substrate made. In addition, to achieve effective application of electromagnetic pressure, the theoretical formula for electromagnetic pressure used in the previous study was modified, and an evaluation formula was devised to match the authors，experimental system.

Investigation of heat transfer phenomena near the wall in the internal combustion engines contributes to improve the thermal efficiency by reducing the cooling loss. MEMS heat flux sensor is capable of instantaneous measurement of flux with by using the heat conduction analysis. It is theoretically possible to estimate the advection velocity along the wall using three-point heat flux information. However, due to the size of fluctuations and the influence of vertical velocities, the estimated velocity can vary significantly. Therefore, we are attempting to improve the accuracy of advection estimation by adopting only the results with high consistency in estimated values from four or more multi-point heat flux information. We fabricated three types of multi-points sensors : four-points, five-points and seven-points. We measured the heat flux trends from high temperature air flow with the sensors, using three dimensional heat conduction analysis. Estimation of ethe advection velocity was tested by using delay times of adjacent three heat flux trends measured with the seven-points sensor.

Recently, it is necessary to develop technologies for utilizing waste heat, due to problems of global warming and depletion of fossil fuels. Therefore, a new engine with the Leidenfrost phenomenon have been developed in our laboratory. In this study, we investigated how the evaporation time of droplets, especially neat the Leidenfrost point, changes when different amounts of D.I. water or methanol are dropped. D.I. water and methanol have different Leidenfrost points, different behaviors when the volume is changed, and a difference trend of the change of the evaporation time in the temperature range lower than the Leidenfrost point. From the results considering with our knowledge, it is suggested that the difference in vapor film thickness at the target temperature with reference to the boiling point causes such a difference.

It is well known that the Leidenfrost phenomenon occurs when a droplet approaches a hot surface. In our laboratory, targeting droplets of several micrometers size, a system for directly observation of the droplets flying in a high-temperature field have been developed and the analysis of the behavior of such small droplets in the Leidenfrost state have been focused. In this presentation, the problems and improvement of the equipment which is a home-made will be reported. Also, observation results of D.I. water and methanol droplets will be announce. For reference, in general, the droplets of methanol evaporated faster than that of D.I water, because it have a lower boiling points than water, even for minute droplets. which has a lower boiling point than that of water it was confirmed that methanol, which has a lower boiling point than that of water, evaporates faster than D.I. water.

In order to manufacture highly durable solid oxide fuel cell (SOFC) electrodes, a technique is required to accurately assess the thermal stress distribution within porous electrodes. However, the traditional numerical simulation methods, such as the finite element method (FEM), are often computationally expensive and time-consuming. To address this issue, we have developed an efficient deep learning model utilizing Generative Adversarial Networks (GAN), which is capable of predicting the thermal stress distribution generated in porous materials under biaxial constraints. We show that our Pix2pix GAN model predicts the stress concentration regions within the 2D cross-sectional images extracted from their 3D microstructures with high accuracy, particularly by incorporating 3D density information into the training data. Furthermore, we provide an effective method to create more realistic training data by combining the numerical simulations and the existing deep learning techniques. This method allows us to predict the stress concentration regions generated in FIB-SEM actual microstructures with higher accuracy.

To increase the power output of polymer electrolyte fuel cells (PEFCs), careful water management is important, and a micro-porous layer (MPL) suppresses water accumulation near the catalyst layer (CL). This study applied the MPL added with larger size pores to promote the water removal, and investigated the effecs using the extended limiting current analysis developed by the authors. In this method, the increase in oxygen transport resistance due to water accumulation is separated into pressure-dependent and -independent components by introducing two indices determining the condensed water effects. The components approximately correspond to the transport resistances outside and inside of the CL respectively. The results showed that adding larger size pores reduces increases in the oxygen transport resistance under flooded conditions. The extended limiting current analysis revealed that the suppression in the resistance increases is mainly caused by smaller pressure-dependent component. Further, the observation of water distributions by a freezing method and cryo-SEM indicated that condensation of produced water in the large pores inhibits that in the normal pores.

In order to improve the performance of all-solid-state lithium ion batteries, understanding the diffusion properties of lithium ions in solid electrolyte and cathode active material are necessary. However, because the diffusion properties of lithium ions are nanoscale phenomenon, and polycrystalline materials with grain boundaries are often used in the experiments, it is difficult to evaluate the physical properties of materials in ideal bulk crystal states. In this study, molecular potential models are constructed and simulations by molecular dynamics method are performed to analyze the diffusion properties of lithium ions in the solid electrolytes.

In this study, basic experiments were conducted to apply a light-curing 3D printer that uses resin cured by a certain wavelength of light to the fabrication of solid oxide fuel cells (SOFC). When using this method, the volume fraction of ceramic powder mixed in the resin has a great influence on the feasibility of the molded object. The upper limit of the volume fraction to obtain a compact of the target size by 3D printer is 22%, and the lower limit of the volume fraction to obtain a compact of the target size by 3D printer is 22%. The lower limit of the volume fraction that can maintain the shape after firing is determined to be 20%. However, the fired compact is very brittle when the volume fraction is less than 20%, so further improvement is needed to increase the volume fraction.

The aim of this study is to detect defects in polymer electrolyte fuel cells (PEFCs) stack containing two layers of MEA (Membrane Electrode Assembly) by a non-invasive method in a simple and instant manner. In this study, the magnetic flux density calculated by electromagnetic field analysis by the 3D-finite element method was analyzed by inverse problem analysis based on sparse modeling, and the current distribution inside the fuel cell was estimated. Assuming a two-layer stack consisting of a defective MEA with a defect of 10 mm × 10 mm in the electrode of a 50 mm × 50 mm MEA and a normal MEA, the current distribution of each MEA is estimated by inverse problem analysis based on sparse modeling theory. As a result, the estimated current value of the defect position in the defective MEA was 0.00A, and the estimated current value of the other positions was 0.12A, and the defect position could be clearly identified.

Lithium-ion rechargeable batteries are the high-performance batteries in use today. However, there are three problems with the cathode material lithium cobaltate. First, they generate heat during charging. Second, they tend to change their structure during charging, resulting in a decrease in capacity. Third, the cobalt used for the material is expensive and scarce. In order to produce a battery that can compensate for these three points, this study focused on zeolite, which has a strong three-dimensional structure and can store lithium ions within its structure. The incorporation of valence-changeable transition metals into the zeolite's framework structure enables the transfer of lithium ions. Among transition metals, when an element with a large valence change when becoming an ion, such as Mn, is incorporated into the three-dimensional structure of a zeolite and synthesised, the number of lithium ions entering and leaving a single pore increases, making it possible to increase battery capacity. As the crystal structure of the zeolite does not change before and after charging, there is no decrease in capacity, and the higher porosity reduces the amount of heat generated. And the material is cheaper than lithium cobaltate because no rare metals are used. The aim of this research is to develop a new cathode material for lithium-ion batteries that incorporates manganese within the zeolite framework and has a higher capacity and longer life than conventional materials. In this study, Si-Mn-based NaP1 zeolites were synthesised by a melting method. The crystal structure and elemental analysis of the composite using XRD showed that NaP1 zeolite may be formed.

The objective of this study is to investigate in detail the basic combustion characteristics and abnormal combustion characteristics in the engine cylinder during drop-in of a synthetic fuel, dimethyl carbonate, at varying content rates to an existing fuel, Primary Reference Fuel (PRF). An optically accessible engine capable of flame propagation velocity analysis was used for the experiment, and combustion analysis was performed by visualization in the engine cylinder and in-cylinder pressure data acquisition. As a result, the experiments showed that the flame propagation velocity in the actual engine slowed down as DMC was included. Next, under the condition of 40% DMC content and less influence of residual gas, the knock resistance was not improved, and the knocking intensity was higher than that of the existing fuel. Finally, under conditions with 80% DMC content and high residual gas in the cylinder, combustion variation and misfire cycles were found to increase. The cause was found to be a prolonged initial combustion period.

A discrete model of the combustion process for controlling an HCCI engine is developed, and its prediction accuracy of crank angle, pressure and temperature is evaluated. The combustion process is discretized at several points based on the mass burning rate. The model is designed to calculate the state in the cylinder at each point by a formula that follows the physics laws as much as possible. As a result, the complex heat release and pressure history of the combustion process of an HCCI engine can be predicted with some accuracy and a light computational load without using a complete statistical equation such as the Wiebe function. But the prediction accuracy of the entire model is still not good and needs to be improved in some parts. In particular, the changes in the cylinder condition immediately after ignition are not well predicted. The model immediately after ignition needs to be re-examined.

One of the methods to operate a gas engine with high efficiency is the use of an pre-chamber, which enables stable combustion of lean fuel mixture. Models have been developed to control the pre-chamber gas engine; however, there is room for improvement in terms of computational accuracy. Therefore, in this study, we focused on the control of pre-chamber gas engine and conducted the construction and evaluation of a combustion model from the closing timing of the intake valve in the pre-chamber to the end of combustion in the pre-chamber chamber. The results showed that the predictive accuracy of the constructed model was not enough. However, considering factors such as cooling losses at the engine walls and the inflow of gas between the pre-chamber and main-chamber, it is anticipated that the predictive accuracy can be enhanced.

Soot particles were formed at 0.1MPa and 1333K using a micro-flow reactor fueled with 2% propane diluted with nitrogen, and the particle size distributions were measured. The peak of the distribution shifted to the larger particle size side as the reaction time increased. Furthermore, we tried to calculate the particle size distributions by the sectional method. The value of Ca (van der Waals enhancement factor) in the collision frequency function in the particle coagulation process was varied from 1 to 3 and compared with the measured distributions. As a result, it was found that the calculation results close to the measured distributions were obtained around Ca =2.5 to 3.0.

This paper reports a novel method of energy harvesting by exploiting thermoacoustic self-excited oscillations in a looped tube filled hermetically with atmospheric air. The oscillations are excited spontaneously by imposing a temperature gradient on a porous stack made of ceramics sandwiched by hot and cold (ambient) heat exchangers. A pair of identical stacks is placed in the tube at diametrically opposite positions so that the temperature gradient may be in the same direction. A single Wells turbine with a DC generator connected coaxially is installed inside the tube near a pressure node of the 1st mode or the 2nd mode of oscillations. The turbine starts to rotate spontaneously and generates a voltage from oscillatory airflow of 24 Hz (1st mode) or 49 Hz (2nd mode). The maximum voltage of about 10 volts is generated across two open terminals of the generator, while the maximum power of about 1.3 W is extracted at 6.4 V when a resistor of 30 Ω is loaded for the 1st mode of the oscillations. It is found that the Wells turbine, which was originally developed for energy harvesting from an oscillating water column of low frequency, can be applied to generate electricity from the thermoacoustic oscillations of high frequency.

Realization of reliable hydrogen combustion aero engines enables small UAVs(Unmanned Aerial Vehicles) to choose various types of power sources. Some trial runs of a micro reciprocating engine with hydrogen fuel were conducted. We used an FG-11 4-stroke gasoline engine for radio-controlled model airplanes, which have a displacement of 10.9 cm³. The engine showed excellent startability. Hydrogen-air premixture immediately ignited after supplying hydrogen fuel. When the equivalence ratio of the premixture was under 0.2, the continuous operation was achieved. At higher equivalence ratio, the engine speed gradually decreased, and it stopped eventually. Another type of lubricant which have higher flash point was used to prevent burning itself, but the problem was not resolved. The temperature distribution near the combustion chamber was increased when stopping. This suggests the clearance between piston and cylinder becomes not appropriate at higher equivalence ratio.

Tohoku Electric Power Co., Inc. has systematically promoted the replacement of aging thermal power stations and has developed the latest thermal power sources that are cost-competitive and contribute to the reduction of environmental impact.

Joetsu thermal power station No. 1 uses the JAC (J-series-air-cooled) gas turbine, which is the latest model of the J-series gas turbine with a turbine inlet temperature (TIT) of 1,600°C upgrade to TIT of 1,650°C, and started commercial operation in December 2022.

This thermal power station incorporates the latest technologies and knowledge throughout the plant, achieving the world's highest plant thermal efficiency of 63.6%. Compared to conventional gas turbine combined cycle power generation facilities, we have achieved improvements in facility operability such as shorter plant start-up time, faster power generation output change speed, and lower minimum output.

An SOFC triple combined cycle power generation, consists a solid oxide fuel cell and gas turbine combined cycle is revealed to give efficiency improvement while reducing the amount of emissions in power generation. It comes from the fact that the exhaust heat generated from a cycle is further utilized for power generation in the next cycle. Studies concerning its designs and optimizations have been investigated, including the load-following response of the SOFC- TCC system. The hydrogen fuel consumed will be provided by a hydrogen generation system of proton exchange membrane electrolyzer (PEMEC). The SOFC- TCC system is interconnected with a substation of renewable energy for green hydrogen prodcution, where surplus energy from the renewable is utilised to power the electrolyzer. The system shows adequate load-following response of G/T ans S/T. Whereas SOFC load-following response of SOFC needs to be improved for it directly affected the system’s frequency, specifically frequency deviation. The hydrogen generated by the PEMEC is insufficient to fuel the whole system which leads to consideration of other hydrogen generation and/or supply method.

This study investigates a combined solid oxide fuel cell (SOFC) CO2 utilization system that employs green hydrogen methanolization and methanation to utilize the CO2 captured by the system. The system is able to efficiently utilize the CO2 generated from power generation and effectively reduce CO2 emissions from power plants. Carbon dioxide is separated from the exhaust gases of the system and is captured, stored and efficiently utilized through methanation and methanolization. The synthesized methane is used for SOFC power generation and the synthesized methanol is sold. The economic benefits of the proposed system were evaluated using a discounted cash flow approach. With a unit electricity price of $0.36/kWh (rated output = 750 MW, PV capacity = 151.3 MW, discount rate = 3%, methanization reactor share = 50%) and considering periodic replacement of equipment over time, the simple integration of the system has a balanced payback period of 9 years, a NPV of 10 years, and a dynamic payback of 18.86 years, which indicates that the proposed system is economically viable. This indicates that the proposed system is economically feasible.

In snowy regions, a substantial amount of revenue is spent on snow removal. Snow removal is essential due to the risks it poses, such as traffic congestion and building collapses. Using a Stirling engine with snow as a low-temperature heat source can potentially achieve both snow melting and carbon neutrality. The Stirling engine operates based on expansion/compression phenomena when air is heated/cooled. It is known that the Stirling engine achieves higher thermal efficiency with larger temperature differentials. In this study, high-temperature sectionof the engine was heated with concentrated sunlight using Fresnel lenses so as to get higher temperature on that section. The results showed an average power generation of 173 W, and the exhaust heat from the engine could be used to melt the snow. The challenges identified include the need for continuous solar tracking for optimal power generation and the prevention of heat loss in the high-temperature section of the engine. We are planning to continue conducting further studies to achieve more efficient power generation and snow removal, moving towards practical implementation.

The OME (polyoxymethylene dimethyl ether) synthesized from CO₂ captured by carbon recycling technology and H₂ generated from renewable energy, is of interest as a carbon-neutral automotive fuel. The OME is expected to be an alternative diesel fuel because it has oxygen atoms in its molecule and no C-C bond. It has consequentially showed a positive effect in extremely low soot emissions compared with diesel fuel. However, there have been no comprehensive studies of the effects of multi-hole nozzle injection on OME spray and combustion characteristics. In this study, the effects of multi-hole nozzle injectors on spray, combustion, and emission characteristics are investigated by performing OME spray simulations that would accurately reflect the characteristics of each nozzle-hole injection quantity. In order to obtain the parameters necessary for simulation model, spray visualization and injection rate measurement were carried out using a constant volume vessel and momentum method respectively. The experimental result showed that the variation in spray penetration length and injection rate between nozzle holes increased in the enlarged nozzle hole injector. In numerical simulation, our simulation method accounting the injection rate of each hole was applied which was different from the conventional method using a single injection rate representing multi-hole quantities. The ignition delay time measured from the conventional simulation method was found to be 0.025 MS equivalent to 0.30 CAD at 2000 rpm and shorter than that using our method.

Today, there are strict environmental regulations for automobiles, including noise control. Although, there are numerous studies focused on diesel engine noise, research on noise generated by fuel injection has been relatively limited. Therefore, it was promoted the scope of this study. In diesel engines, common rail system has been introduced to increase injection pressure to improve combustion. Currently injection pressure of 100 MPa ~ 200 MPa is available, resulting in higher impact and oscillation of fuel line pressure during injection. Therefore, the noise from injection system may be also enlarged. Hence this study aims to reveal mechanisms of noise generated from pressure fluctuations by diesel engine injection system. Firstly, a mathematical model imitating fuel pressure fluctuations on an injector and a fuel-delivery pipe was constructed. Secondly, the noise generated from injection system during an engine running was recorded and used to spectrum analysis. By comparing the numerical calculations from the model with the noise characteristics, the mechanisms of pressure pulsation generation were analyzed.