To establish a technique to measure the wall shear stress with high accuracy, along with the spatial and temporal resolutions, micro-scale sensors are fabricated and their responses to the wall shear stress are investigated. In this study, two types of micro-scale sensors are fabricated: a hot-film (HF)-type sensor and a floating-element (FE)-type sensor. First, the HF sensor is calibrated using a rotating cylinder. The calibration results show that the heating power of a constant temperature circuit (CTC) increases with the wall shear stress. The relationship between the square of the heating power of CTC (E₁²) and the wall shear stress to the 1/3 power (τ_w^1/3) becomes linear in the range τ_w^1/3 > 0.35 Pa^1/3 as theoretically predicted. Second, the calibration of the FE sensor is performed using the Stokes layer excitation method. The calibration results show that the output voltage of the C-V conversion circuit connected to the FE sensor E₂ is almost proportional to the wall shear stress τ_w as expected in the range τ_w > 2.5 × 10^-4 Pa for 100 Hz stokes layer excitation and τ_w > 5.0 × 10^-4 Pa for that of 200 Hz.

View full abstract

The flow around a square-section cylinder was investigated by means of experiments and numerical simulations at a Reynolds number of 1,000. The effects of wall confinement on the flow characteristic were studied. The characteristic relationships between the vortex size in the wake, the vortex shedding frequency and the fluid forces on the cylinder are presented for different values of blockage ratio. As a result, it was observed that presence of wall confinement suppressed the vortices in wake, and increased the vortex shedding frequency and the drag force on the cylinder.

View full abstract

In this study, we used the developed Stokes polarimeter for concurrent measurement of the magnetic-field-induced linear birefringence and dichroism in composite magnetic fluids (CMFs). CMFs were obtained by doping nonmagnetic microspheres into pure ferriferous oxide (Fe₃O₄) MFs. Experimental results show pure Fe₃O₄ MFs of different volume particle concentrations and CMFs doped with polystyrene (PS) microspheres of equal quantity have similar variation trends for the retardance and dichroism under externally magnetic field. The relation between the linear birefringence and dichroism of CMFs doped with PS microspheres of different concentrations and those of pure Fe₃O₄ MF were investigated. It is found that the suppression of both retardance and dichroism increases with the increasing concentrations of PS microspheres in CMFs. One of double doped microspheres as PS in CMFs plays a dominate role than the other microsphere as silica for the suppression of both retardance and dichroism.

View full abstract

A binary temperature-sensitive magnetic fluid (binary TSMF) is a mixture of a temperature-sensitive magnetic fluid and low-boiling point organic solution. An external magnetic field and heat are able to actively control the thermal flow behavior of the binary TSMF. In the present work, we make a miniaturized magnetically-driven heat transport device using the binary TSMF with the diameter of the tube of 1.54 mm, and investigated the flow characteristics at different magnetic field intensities andheating conditions. The results show that maximum flow rate is 1646 μl/min (maximum velocity 14.7 mm/s). The flow rate depends on the external magnetic field intensity, heat flux and the heating position with respect to the magnetic field distribution.

View full abstract

Dispersing fine particles of refining agents uniformly into a molten metal bath plays an important role for enhancing the efficiency of metal refining processes such as the desulfurization process. The densities of the particles are usually smaller than that of the molten metal. Water model experiments are carried out in this study to understand the dynamic behavior of the particles. Low-density spheres made of polypropylene are chosen as the model particle and vertically dropped onto the surface of a water bath. The wettability of each sphere is changed by coating water repellent on its surface. An air cavity is formed behind the sphere under a certain condition. The maximum cavity depth, the time required for the cavity to break up, and the maximum penetration distance are measured using a highspeed camera and compared with their respective empirical equations proposed previously for a single poorly-wetted sphere. These quantities can be correlated in terms of the Froude number similitude.

View full abstract

The conditions which can be acquired the cold gas efficiency of over 70% were experimentally clarified by using porous alumina as bed material in a laboratory-scale hot model gasifier. The tested biomass is wood pellet. As a result, the amount of H₂ formed was more increased by steam reforming of coke and steam gasification of char in steam gasification. The cold gas efficiency of more than 70% was obtained at 973 K in the pyrolyzer, at 1153 K in the gasifier, and 1.6 of S/C which is the molar ratio of the steam feed rate and the carbon content in the raw fuel.

View full abstract

The objective of this study is to improve the lower frequency sound of the sound source, which derives from the diameter and the speed of water-droplets, in the water musical instrument. Their diameter and speed are changed by varying nozzle diameter and water pressure, respectively. As a result, the lower frequency sound based on the vibration of large air bubbles is influenced by the nozzle diameter, but its frequency is not in proportional to the size of nozzle diameter. The quality of the sound radiated from the water musical instrument is improved by matching the diameter of the air bubble to the length of the resonant pipe.

View full abstract

We developed a new method for the fabrication of hollow microcapsule blowing the vapor of moisture curing polymer into water as microbubbles. The fabricated hollow microcapsules have biocompatible shells and are smaller than blood capillaries. Thus, the acoustic behavior of such microcapsules was observed ultrasonically and optically in the flow channel. These experimental results revealed that such microcapsules have the transportability of adhering materials on the surface and can be used in ultrasound imaging.

View full abstract

A micro laminar premixed flame stabilized by an annular pilot flame is observed. The flame is formed even on a burner whose diameter is 0.3 mm. However, the shape of the flame formed on the burner whose diameter is less than 1mm and at around the lowermost flow rate is nearly spherical. It is similar to the appearance of a micro diffusion flame. The flame formed on the burner which has a diameter less than 1 mm is not considered a propagating flame, because a typical laminar propagating flame has a structure thickness that is more than 0.5 mm. The flame structure variation and the uppermost and the lowermost flow rates that the flame could be formed stably were observed. Consequently, it is supposed that the flame formed on a burner with a submillimeter diameter is dominated by the diffusion mixing of oxygen and methane from the main premixture flow, and heat and radicals from the pilot flow. The extinction mechanism of the micro premixed flame was examined and the scale effect on the extinction limit and the flame structure were considered.

View full abstract

Sonochemical process refers to a physical or chemical reaction that uses the high pressure and temperature field in a bubble’s volumetric oscillation induced by an ultrasonic pressure oscillation. We developed a sonochemical reactor using a hollow cylindrical ultrasonic horn capable of generating many microbubbles from the orifice at its end. This reactor can decompose a persistent substance in a liquid because immersion of the horn’s end into the liquid can allow for intense ultrasonic irradiation close to the generated microbubbles. In this paper, we report the influence of the gas flow rate and the surfactant addition on the microbubble-mediated degradation of indigo carmine.

View full abstract

This paper studies the shape of jet diffusion flame, whose burner diameter is less than 1 mm. Previously, it has been assumed that the buoyancy force has little influence on the shape of a flame of such a scale, owing to the large value of associated Froude number.However, little is known on the critical burner diameter over which the buoyancy force begins influencing the shape of flame. The lengths of butane diffusion flames are measured using three burners of different diameters to vary the Froude number. The results are understood on the basis of a flame-length theory developed by the authors.

View full abstract

Background oriented schlieren (BOS) technique is the novel image processing technique which enables us to measure the quantitative density distribution in compressible or convective flow field. The colored-grid background oriented schlieren (CGBOS) technique has been developed in our advanced approach using colored-grid pattern as a background image. The CGBOS computed tomography (CT) method is based on the multi-images of 2D quantitatively integrated distribution data of refractive index gradient around a test model in supersonic flow. These images are calculated by the distortion of the background stripes image. We picked up a square-pyramid nose (asymmetrical) model for our CGBOS experiment. The blowdown-type supersonic wind tunnel of JAXA-ISAS was used, and from 19-2D images of every 5 degrees, we reconstructed the 3D density gradient information from CGBOS and ART-CT technique.

View full abstract

Laser Interferometric Computed Tomography (LICT) measurement is practically useful method to measure quantitatively supersonic unsteady flow field, and threedimensional (3D) density distribution is obtained. In our previous study, the 3D flow fields have been observed by LICT measurement. However, it is still difficult to measure 3D density distribution of the different times in CT reconstruction technique (4D-CT). In this study, to realize the novel 4D-CT measurements, high-speed camera is applied to our LICT measurement. This is because successive images at sufficiently short intervals can be obtained by high-speed camera.

View full abstract

This paper presents a novel ground-based methodology to investigate an important characteristic of fire in space. Based on the concept of scale modeling - Grashof-number (Gr) similarity -; the transport process found in small-scale fire in low-pressure (on earth) should be similar to that in space. Our similarity approach has successfully achieved to form the nearly-spherical shape of flame over the small rod-shaped combustibles (e.g., electric cable) by adopting the low pressure. Important finding is that the flame spread rate becomes faster in low-pressure than that in the normal-pressure and this is exactly the same with what found in low gravity experiment. This paper demonstrates the advantage of the scale modeling to predict the extraordinary fire in a simple way.

View full abstract

The diffusion flames under the conditions of Re = O(1~2) and Fr >> 1 become spherical shape. Since the size of flames that satisfies the conditions is usually small, they are called microflame. As for microflame, the whole flame zone exists close to the burner tip, typically within a few mm. Such condition is quite different from other conventional burners.The effects of burner condition need to be examined for fundamental understanding of microflames and simulating droplet combustion. The effects of burner size and material on the lower extinction limit of methane diffusion microflame are measured by changing an inner diameter of burner outlet in the range from 0.7 mm to 4.3 mm and by using SUS 304 and copper burner. The burner with smaller thermal conductivity (SUS 304) shows lower fuel flowrate at the lower extinction limit. The lower extinction limit of fuel flowrate decreases with decreasing burner diameter, owing to the effect of smaller heat transfer cross-sectional area, which is more dominant than the effect of thermal conductivity and temperatures of fuel and burner.

View full abstract

This paper presents a method of energy conversion for an electromagnetic oscillation to electrical micro-power using magnetic-elastomer, and this method can efficiently scavenge power generator from low-frequency external vibration. In the present study, we focused on comparing experimental data to theoretical analysis in newly made experimental set up with various magnetic-elastomers. The theoretical analysis is based upon the law of Faraday's electromagnetic induction, in which the induced electromotive force can be estimated from the vibration of the magnetic-elastomer under the magnetic field. From the result of experiment, it was found that the measured peak output power was 5.64 μW at 1.6 Hz. The theoretical analysis revealed that data obtained in the experiment are well explained by means of alternating internal magnetization. Also in the present study experimental results are correlated with non-dimensionalized parameters, which involve all essential material parameters and governing dynamic properties.

View full abstract

The drought risk evaluation of cultivating plants is the most important factor on deficit irrigation (DI). The DI, however, often causes the cavitation and embolism followed by growth inhibition of the plant. Acoustic emissions (AE) detected on a stem are associated with cavitation. Authors proposed the model in which the change in AE behavior against the change in drought stress reflects the embolism risk. Furthermore, a stress wave velocity (SWV) through stem was measured to guarantee the decrease in the drought stress of a soil-cultivated plant. In this study, the hybrid measurement of AE and SWV at stem of miniature tomato was done for controlling DI. The change ratio of SWV caused by irrigation, R_IV depended on the drought stress. The plants suffered severe drought stress showed that the change ratio of AE occurrence rate caused by irrigation, R_IAE was increased. The DI using R_IV and R_IAE was successful to maintain the yield of fruits with high sugar content.

View full abstract

This paper describes the relationship between the strength of a joint created by an ultralow-loading diffusion bonding method and the dimension of unit disk parts machined by an ultra precision lathe. Oxygen-free copper disks of 30 mm diameter were machined by an ultra precision lathe, and the roughness, flatness, and undulation of the surfaces were analyzed. After the disks were subjected to an ultralow-loading diffusion bonding process in a vacuum furnace, the tensile test for the bonded joints was conducted. The configuration measurement showed that flatness was on nanometer order and that undulation could be classified as convex, concave, and straight. Regarding the joint strength, a tensile strength of around 200 MPa was obtained by specifying an initial gap at the two bonding surfaces ranging from 0.1 to 0.2 nm, under a bonding temperature of 973 K and a bonding pressure of around 1/1000–1/3000 of the yield stress of copper at that temperature.

View full abstract

This paper presents the transmission ratios of a strain pulse at various types of adhesive joint measured using strain gages. An impact compression load was applied by a pendulum to the joints of polymethylmethacrylate plates, such as a simple butt contact, a butt-bonded joint, a uniform lap-bonded joint, and offset lap-bonded joints. The transmission ratio T_rε of strain is defined as T_rε = ε_t / εi, where εi and εt are the strain pulse amplitudes measured in the incident and transmission plates, respectively. The strains were measured immediately after the arrival of a reflected wave at their measuring points. T_rε for the lap-bonded joints was larger than that for the simple butt contact; however, T_rε did not always increase with increasing lap width. The transmission ratio of the impact stress and the propagation of the stress wave are discussed on the basis of the results of numerical analysis using LS-DYNA software.

View full abstract

In this study, we set a single arm robot and load mass on the center of experimental Quad Rotor Helicopter (QRH). When the robot arm tilts in small angle (~30 degrees), this motion generates load torque to tilt the airframe of QRH, and then attitude control system generates counter torque to cancel the tilt angle. As the result, small inclination exists when counter torque balances to load torque. This small inclination generates moving thrust, and QRH starts to slide. This result means that we can control QRH with external independent devices attached on it.

View full abstract

On March 11 in 2011, a very big earthquake occurred in Tohoku district in Japan. Huge tsunami was generated by this earthquake. Many houses were destroyed by tsunami and a large amount of rubble was generated. At the same time, a large amount of tsunami sludge deposited on land. If the high quality ground materials and cover soils can be produced from waste woods and tsunami sludge, it can be considered that the restoration and reconstruction in the disaster areas will progress greatly. In this study, the mixtures of wood chips and tsunami sludge were modified by Fiber-cement-stabilized soil method, and the strength characteristics of modified soils were experimentally investigated. Furthermore, durability for drying and wetting were investigated in order to use the modified soils as cover soils for radiological contaminated excavated soils in Fukushima Prefecture. It was found through the experiments that modified soils have enough failure strength, failure strain and durability for drying and wetting, and can be used as ground materials or cover soils.

View full abstract

In-plane tensile and through-thickness compressive stress-strain characteristics of Al alloy 2024-T3 and its butt welds made by the friction stir welding (FSW) process are studied. FS welded AA 2024-T3 butt joints are produced under a fixed set of appropriate welding conditions. Microhardness tests are performed to examine the microstructural change occurring during the FSW process. In-plane tensile and through-thickness compressive tests on the base material and the FS welds are carried out in an Instron testing machine. Flat tension specimens are machined perpendicular to the weld line of each FS weld. Cylindrical compression specimens are machined along the thickness direction of the base material, heat-affected zones and nugget regions in the FS welds. It is shown that their tensile and compressive stress-strain behavior can be adequately modeled by a three-parameter Ramberg-Osgood equation.

View full abstract

In this work a material parameter identification procedure is presented which utilizes optical full-field displacement measurement data and digital image correlation. It is based on the Finite Element Model Updating (FEMU) principle and is controlled via an optimization algorithm. The parameters which are identified define the shape of the initial yield surface. The numerical material model is based on an orthotropic elasto-plastic approach at finite strain with a Hill-type yield function. The model is implemented into a commercial Finite Element (FE) simulation software tool. The tested material is a 2.0mm DC04 sheet steel which shows orthotropic characteristics. The objective is to identify the optimal material parameters at minimal experimental costs. The utilization of a biaxial tensile test with a self-designed specimen geometry leads to very well fitting results. The parameters identified with the FEMU procedure are verified through experimental testing by performing uni- and biaxial tensile and compression and shear tests.

View full abstract

Titanium fiber thin plates were formed by a compression shearing method at room temperature. The effect of the fiber aspect ratio on the microstructure, strength properties, and porosity of the formed samples were examined. As a result, the surface roughness was constant at approximately 5.4um, and the patterned indented surface was homogeneous and isotropic. The porosity of the samples was found to increase from about 32.1 to 39.9% by increasing the aspect ratio of the titanium fiber. The elastic modulus of the samples increased with increasing the aspect ratio of the titanium fiber. In addition, the bending elastic modulus and the bending strength remained constant at approximately 50 GPa and 310 MPa, respectively.

View full abstract

With the aim of estimating the collision speed of a vehicle in a pole side impact accident, dynamic lateral local compression (D-LLC) and dynamic three-point bending (D-3PB) modeling tests were carried out. These tests were performed using rectangular metal tube specimens, and the deformation results were compared to those of an experiment vehicle during pole side impact. The results indicated the possibility to estimate vehicle deformation during pole side impact by D-LLC and D-3PB testing of rectangular metal tube specimens.

View full abstract

A pendulum-type viscoelastic spectroscopy is developed to experimentally measure loss tangent and the magnitude of dynamic modulus of solid materials. The experimental apparatus consists of the Helmholtz coils to generate torsion and pure bending moments on the cantilever beam specimen. A permanent magnet is attached to the free end of the specimen to interact with the magnetic field generated by the Helmholtz coil. Sinusoidal driving signals are adopted for measuring complex modulus, and dc bias driving for creep tests. Deformation is monitored by the laser-based displacement measurement system. In the sub-resonant frequency regime, the complex modulus can be obtained by directly analyzing Lissajous stress-strain curves, provided the phase angle is not extremely small. At the structural resonant frequency, the Lissajous method fails, and hence the full-width-at-half-maximum (FWHM) method or lorentzian curve fitting method is adopted. In the low frequency limit, the loss tangent can be calculated from measured creep compliance with the Kramer-Kronig relationship.

View full abstract

The hexagonal digital moiré method for analyzing the planar structural information of hexagonally assembled micro/nano structures is presented in detail. The structure of a micro hexagonal mesh fabricated by ultraviolet nanoimprint lithography is characterized. A three-way grating is constructed as a reference grating, whose pitches in three directions are close to those of the 1D arrays of the micro hexagonal mesh. The pitches and the orientations of the three 1D arrays in three directions are simultaneously measured. This method is effective in evaluating the fabrication quality of a hexagonally assembled structure in a large view field.

View full abstract

The effects of non-stoichiometric curing on the dynamic compressive properties of bisphenol A-type epoxy resins were investigated experimentally to take into consideration the relation between mechanical properties and network structures in the epoxy resin. The yield stresses were found to be approximately linear to the strain rate regardless of crosslinking densities. Stress after yielding was clarified to rapidly reduce in epoxy resins with lower crosslinking densities and for higher strain rates.

View full abstract

The effects of strain rate and testing temperature on the compressive behavior of a Mesoalite (Meso10 alloy) have been investigated. In both the quasi-static and impact test, the flow stress decreased with increasing testing temperature. In addition, an increase in compressive strength with strain rate did not occur in the impact test, in comparison with the quasi-static test. Furthermore, application of the thermal activation theory showed that the deformation of Meso10 alloy obeys a single thermal activation process.

View full abstract

The static and dynamic compressive properties of polypropylene/Degra-novon polymer blends after outdoor (natural) weathering and accelerated weathering tests were measured using a universal testing machine and a split Hopkinson pressure bar. Degra-novon in polyolefins, such as polypropylene and polyethylene, accelerates the environmental degradation process by providing a directly digestible component, facilitating oxidation and/or photodegradation of the polymer chains. The relationship between the mechanical properties, differential scanning calorimetry results, and Fourier transform-infrared spectroscopy data were also examined.

View full abstract

This paper reports the development of a multiple microphone system for measuring acoustic cavity resonance of a tire model. Distribution of sound pressure level is measured in the tire model by the multiple microphone system. This system is composed of 32 condenser microphones mounted concentrically on the upper side of the model. The first and second modes of acoustic resonance were observed by the system.

View full abstract

Porous materials are very unique materials that have many characteristics such as light weight, filtering, shock absorbing properties, etc. Especially, a porous material is thought to be a multi-functional material which has shock absorbing and damping properties. In this study, the local deformation during a short-time deformation of a porous metal was observed by the moiré method using a digital high-speed camera. A 50µm square grid made of stainless steel or a polymer was placed on the surface of the porous metal and polymer for the model grid and an image sensor from a digital high-speed camera was used for the master grid of the moiré method. The impact test (dropping weight test) was used to measure the deformation of the porous materials during a very short time and was obtained from the moiré fringe produced by this method. The strain caused in a very short time was also measured by this method.

View full abstract

Phase-shifting digital holography must capture several holograms. A shift mechanism is also essential. The conventional method utilizes a shift mechanism with feedback control of a piezoelectric device (PZT). In my laboratory, we developed a phase-shifting mechanism using a small, inexpensive PZT without feedback control. This phase-shifting mechanism is called as an interferometer trigger mechanism. In this study, the displacement distribution of a cantilever is measured using a shift mechanism with feedback control of a PZT, and a shift mechanism with an interferometer trigger. A comparison of the results indicates the effectiveness of the interferometer trigger mechanism for the measurement of displacement distribution.

View full abstract

Shape measurement using the whole-space tabulation method (WSTM) is a non-contact approach that has high accuracy. However, unfocused images affect measurement accuracy in practical applications. Errors occur in the analyzed phase near boundary areas with large contrast in unfocused images. In this study, measurement error is reduced. First, experiments are performed to confirm that low reflectance areas are significantly affected by high reflectance areas. Second, an error reduction method using two cameras for the WSTM is proposed. When two cameras capture images from the left and right sides of the projector, the phase-coordinate tables are nearly reversed. Thus, the measurement errors are also nearly reversed in the measurement results of these two cameras. The measurement accuracy is increased by averaging the two sets of measurement results. The WSTM measurement results of the two cameras share the same coordinate system because the WSTM uses a table with a shared reference plane. Therefore, the synthesis of the left and right measurement results is simple using the WSTM.

View full abstract

The structures and strengths of the joining interfaces between Mg-10mass%Al alloy and cast-in inserted transition metal cores have been investigated. Three kinds of core materials were examined: S20C carbon steel, SUS304 stainless steel and titanium. The Mg-Al alloy specimen had higher shear strength than the pure Mg specimen for every core material. Molten Mg does not react with these core materials. On the other hand, molten Mg-Al alloy reacts with each core material and produces metallurgical joint with the core. The Ti core provided highest shear strength.

View full abstract

In order to produce a Raney copper catalyst on the inner wall of microchannels, alkali leaching of Cu-Al alloy microchannel lining layers was investigated. Aluminum concentration of the lining layer decreased with leaching time when the lining-layer surface was exposed to a leaching solution. Furthermore, a fine copper structure was formed where aluminum was leached. This result indicates a possibility of fabrication of Raney copper catalyst.

View full abstract

A novel process to produce a transition metal alloy thin tube in a dissimilar metal body was examined by modifying the conventional sacrificial-core method. A compound containing titanium powder and a compound with aluminum powder were assembled and shaped into a tube-forming compound wire with concentric layers. An iron powder compact including the tube-forming compound wire was thermally dewaxed and sintered. As a result, a thin tube composed of Ti-Al alloy was directly produced in the iron body.

View full abstract

We investigated the anodic oxidation of planner Al-Zn lining layer in a phosphoric acid solution to produce a nanoporous oxide film. The Al-Zn lining layer was produced by a sacrificial-core method using aluminum powder and zinc plate. No nanoporous structure was observed in the specimen after anodic oxidation at 50 V and 100 V for 7.2 ks. On the other hand, well-developed nanoporous structure was formed in the entire region in the case of 150 V for 7.2 ks or longer.

View full abstract

We investigate the effects of process conditions on the formation behavior of microchannels in reactive-sintered Ni-Al alloys as a part of a study to develop a powder-metallurgical process to produce a transpiration-cooling device including microchannel networks for a disaster preventing robot. The microchannel was successfully produced by a sacrificial-core method with a compact specimen composed of Ni and Al elemental powders when a moderate heating pattern was employed for sintering.

View full abstract

The tendon is strong tissue that connects the muscle to the bone, and it is necessary to reveal the mechanism of the damage process in the tendon. This study aims to reveal the damage accumulation process of the tendinous tissue with AE Technique. Tensile tests were carried out, and AE signals were detected before the maximum stress. Therefore, the AE technique can find some fiber failure. With using Digital Image Correlation (DIC) technique, the some fiber failure on the surface of the tendon can be seen when the AE signals detected.

View full abstract

In this study, we aimed to understand the dynamics of a lower limb plastic ankle-foot orthosis (PAFO) during walking in terms of the extent to which it assists or restricts the user’s gait. For this propose, we developed a load measurement system that can directly measure the loading on the PAFO. The system is worn by the user and incorporates four sensors: six-axis force sensors at three points (two in the shoe sole and one in the orthosis) and a single-axis force sensor at the ankle. The top section of a PAFO was divided into upper and lower sections at the back, essentially eliminating its deformation during walking, and a six-axis force sensor was incorporated at this point. The two six-axis force sensors were placed between the orthosis and the shoe (one at the tip of the toes and one at the heel). These sensors allowed for measuring all external forces applied to the orthosis during walking. By using a PAFO incorporating the developed measurement system, in this study we investigated the behavior of the forces applied to the orthosis with respect to variations in walking conditions, namely cadence (gait speed) and stride length.

View full abstract

The effect of the cross-sectional shape of orthodontic wires on the movement of the molars of a lower jaw dentition subjected to distal loads from an implant anchor, a orthodontic wire and brackets is investigated using a three-dimensional digital image correlation technique. The experimental model consists of the lower jaw, teeth, periodontal membranes, an orthodontic wire, brackets and an implant anchor. Orthodontic wires with circular and rectangular cross sections are used. A force of 5.88 N is applied to the wire near the brackets bonded on the first and second premolars and the first molar. The direction of the force from the horizontal is set to 10º, 20º or 30º. Results indicate that the movement of the molars depends on the cross sectional shape of the wire.

View full abstract

Sensor system for haptic display is important to achieve the feedback of the sense of force in the actuator control. We have proposed a haptic sensor system composed by thin and flexible sensor unit to measure contact pressure and shear stress.
In this study, a sensor system of both the contact pressure and the bi-axial shear stress, which can measure the three dimensional vector information, was developed by improving our previously-developed sensor unit. The wearable sensor system applied to human body and investigates the stress value in several cases of motions. The effectiveness of the sensor system was discussed through those actual measurements.

View full abstract