This paper describes a production planning method for a reverse supply chain, in which a disassembly company takes reusable components from returned used products and supplies the reusable components for a product manufacturer. This method addresses the issue that the timings and quantities of returned products and reusable components obtained from them are unknown. This method first predicts the quantities of returned products and reusable components at each time period by using reliability models. Using the prediction result, the method performs production planning based on Material Requirements Planning (MRP). This method enables us to plan at each time period: the quantity of the products to be disassembled; the quantity of the reusable components to be used; and the quantity of the new components to be produced. The flow of the components and products through a forward and reverse supply chain is simulated to show the effectiveness of the method.

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This paper deals with an adaptive visualization method of the thermal state in machining operation. The visualization is expected to enhance the recognition ability of operators. First, a framework of thermal state visualization is proposed. Then, a sensor-configured heat conduction simulation is proposed as an estimation method of thermal states of the machining workpiece. The method is based on the association of sensed data with the process simulation. As an implementation of the proposed estimation method, a prototype system is developed. After illustrating the configuration of the prototype system, results of a simple example are shown. The results indicate the effectiveness of the adaptive estimation. The influence of measurement points are also evaluated based on the case study. Finally, conclusions and future works are presented.

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For efficient use of machine tools at optimum cutting condition, it is necessary to find a suitable optimization method, which can find optimum feasible solution rapidly and explain the constraints as well. As the actual turning process parameter optimization is highly constrained and nonlinear, a modified Genetic Algorithm with Self Organizing Adaptive Penalty (SOAP) strategy is used to find the optimum cutting condition and to get clear idea of constraints at the optimum condition. Unit production cost is the objective function while limits of the cutting force, power, surface finish, stability condition, tool-chip interface temperature and available rotational speed in the machine tool are considered as the constraints. The result shows that our approach of GA with SOAP converges quickly by focusing on the boundary of the feasible and infeasible solution space created by constraints and also identifies the critical and non-critical constraints at the optimum condition.

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In-process tool life detecting system has been developed. In order to detect tool life, we monitored breakage of an electrical conductive thin film band of titanium nitride (TiN) on flank faces of a ceramic insert that was an insulation material. The conductive band was parallel to the cutting edge and was broken by fracture of the cutting edge or excessive tool wear. A coil and a capacitor were connected in series to the band on an insert to make a series resonance circuit in a tool holder for turning, or in an arbor for face milling. A detecting coil with high frequency oscillator was coupled to the coil in the holder/arbor electromagnetically. An electromagnetic induction between two coils was used to take the signal from the insert. The system developed in this study showed good stability against electric noises radiated from electrical devices of machine tools.

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This paper describes a monitoring method of cutting forces for end milling process by using displacement sensors. Four eddy-current displacement sensors are installed on the spindle housing of a machining center so that they can detect the radial motion of the rotating spindle. Thermocouples are also attached to the spindle structure in order to examine the thermal effect in the displacement sensing. The change in the spindle stiffness due to the spindle temperature and the speed is investigated as well. Finally, the estimation performance of cutting forces using the spindle displacement sensors is experimentally investigated by machining tests on carbon steel in end milling operations under different cutting conditions. It is found that the monitoring errors are attributable to the thermal displacement of the spindle, the time lag of the sensing system, and the modeling error of the spindle stiffness. It is also shown that the root mean square errors between estimated and measured amplitudes of cutting forces are reduced to be less than 20N with proper selection of the linear stiffness.

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Many multi-task machines have been developed recently because of demands for reduction of the number of machining processes. Therefore, in this study, the new measuring method of thermal deviations with the linear axis motion is devised for a multi-task machine. This method is possible to do the same measurement as the method standardized in ISO230-3. Using this measurement system, six thermal deviations with the reciprocating motion of the carriage are measured simultaneously on the actual multi-task machine with the general structure. From the results, we obtain the following conclusions. The method we proposed here has validity. The estimation of the thermal deformation mode is possible with synthetic evaluation of the measurement result from this measuring method.

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This study highlights the influences of pre-treatment and plating conditions on the cutting performance of cBN-coated tools. The pre-treatment evaluations investigate the profile, chemical cleaning, and bombardment conditions of the cutting edge. The plating condition evaluation concerns the influence of TiN and cBN plating conditions. In this paper, TiN plating is employed as a pre-process of cBN plating. Moreover, developed cBN-coated cutting tools were used to conduct cutting experiments for hardened die steel and austenitic structure stainless steels. The results show that the new cBN-coated cutting tools demonstrate effective performance for practical use in industrial applications.

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This paper reports on a new machining device developed for experimental study on machining property of hard-brittle materials under external hydrostatic pressure. A new machining device was developed for two dimensional machining tests as well as in situ observation of a machining process by an optical microscope under hydrostatic pressure up to 400MPa. The device consists of four parts; a high pressure vessel, a pump system, a machining device installed in the chamber and an optical microscope. Detail of structure of the device is reported in the paper. Two dimensional machining tests of a soda glass plate were conducted using the device under four levels of pressure. Results of the machining tests is also reported.

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The intermetallic compound Fe₃Al was processed by a reactive sintering process, and its machinability from the viewpoint of tool wear was investigated using dry turning. In cutting Fe₃Al with a cemented carbide tool, the tool life was approximately one tenth that of cutting carbon tool steel SK3 because of intense flank wear. The tool life for cutting Fe₃Al using the cemented carbide P20(WC-TiC-TaC-Co) tool was longer than for cemented carbide K10(WC-Co). In addition, a cermet tool reached its tool life limit by chipping for the whole cutting speed range measured. The roughness of the machined surface of Fe₃Al cut using a cemented carbide tool was much smaller than for SK3. However, for cutting using the cermet tool, the roughness showed a sharp rise due to chipping. It was found that the wear rate of the WC particles in the tool material is larger than TiC particles. The results of the study suggest that the cemented carbide P20 is suitable for cutting Fe₃Al.

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Machinability study on the drilling of two alpha beta titanium alloy series, Ti-6Al-4V and Ti-5Al-4V-0.6Mo-0.4Fe were conducted using an uncoated carbide drill. The effect of cutting speed on tool life, tool failure mode, cutting force and surface integrity of the drilled surface were discussed. Results showed that Ti-6Al-4V exhibited a more superior machinability property when compared to the Ti-5Al-4V-Mo/Fe alloy system. The tool wear progression when drilling Ti-6Al-4V was lower than that of Ti-5Al-4V-Mo/Fe. The tool experienced similar failure mechanisms which were non uniform wear and chipping when drilling both alloys. At high cutting speed and after prolonged machining, excessive plastic deformation was observed on the subsurface layer of the drilled surface which resulted in increase in the hardness value.

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The use of an ultrasonically activated coolant improves the roughness of a ground surface compared with that of an ordinary coolant. By evaluating the change in working surface conditions, it has been clarified that the ultrasonically activated coolant suppresses loading and wheel wear, and maintains a good the working surface condition. The flushing effect of the ultrasonically activated coolant, promoted by giant vibration acceleration, prevents the deposition and welding of chips on the working surface. Since the density of kinetic energy in the coolant stream increases, the activation helps the coolant to overcome the airflow due to wheel rotation and to reach the grinding point efficiently. This promotes the cooling and lubricating effects of coolant, and then protects the cutting edges from crushing, falling off and dulling. On the basis of the results, it can be said that the effects of coolant activation suppress the generation of scratches, and consequently improve the finished surface roughness.

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In addition to its application in media printing, inkjet printing is becoming an increasingly attractive option for the distribution and patterning of materials for a wide variety of applications. In this study a commercial inkjet printer was modified to study the resolution of fluid dot placement required to fabricate 3D multi-material patterns layer by layer. A Java-based computer program was developed to convert stereolithography (STL) data layer by layer, control ink cartridges individually and print ink with customized fluid dot placement arrangements. The study found that complement printing between nozzles which are 30µm in diameter and 144µm apart is essential to achieve a sufficiently dense 3D pattern. When printed with 36µm vertical spacing a layer thickness of 1.30µm is achievable, and when printing layer by layer, the thickness increases almost at a linear rate.

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The processing conditions for deposition of DLC using the FIB-CVD method were examined in detail. Microstructures and mechanical properties of the DLC specimens were also investigated. The deposition process of the DLC specimen is varied by the probe current of the ion beam. Through these examinations, optimum deposition condition was discussed. HRTEM image and diffraction pattern showed that the DLC specimen had amorphous structures. Young’s modulus and Vickers hardness were in the range of 110-140GPa and 1100-1400HV, respectively. These mechanical properties were obtained similarly even though the processing conditions were changed in our study.

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Clad layers of Ni-based alloy were deposited on the power plant machinery parts made of SUS316LN stainless steel by CO₂ laser cladding and plasma cladding. A smooth clad bead was obtained by CO₂ laser cladding. The phases of the clad layers were investigated by laser microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, electron probe microanalysis (EPMA), and energy-dispersive spectroscopy (EDS). The microstructures of clad layers belonged to a hypereutectic structure. Primary phases consisted of boride CrB and carbide Cr₇C₃. The eutectic structure consisted of Ni + CrB or Ni + Cr₇C₃. Compared with plasma cladding, excellent wear resistance, fine microstructures, low dilutions and high Vickers hardness were obtained by CO₂ laser cladding. All these results show that laser cladding realizes higher efficiency and good cladding quality.

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A new type of tire is presented, in which there is no air leakage when nails puncture the tire. The broken part is repaired automatically by a self-repairing mechanism. The self-repairing unit consists of two rubber sheets with internal lattices. Polymer particles, which expand their volume on adding water, are inserted into the lattices. The unit is adhered to the inside wall of the tire. Coolant fluid diluted with water is introduced to the polymers uniformly. In this system, the polymer particles expand with water-diluted coolant fluid, and become gel. Hence, they stop air leakages in the tire. Fundamental experiments are performed, and optimum conditions are found. This technique is also applied to real tires, and it is ascertained that there is no air leakage when the tire is punctured by nails.

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Transverse vibrations of ropes spanning a high-speed elevator are induced by resonance when a building sways because of an earthquake or wind force. Hence, an effective solution is demanded. In this study, we undertake to suppress the vibration of an elevator rope by using an input device placed in the vicinity of the upper boundary of the rope. This input device has gaps between an actuator and the rope to prevent the progression of their abrasion. A nonstationary control method is effective for the control of a time-varying system with which an elevator rope and a crane wire are categorized. In addition, a sliding mode controller is robust toward nonlinearity at the position where input is introduced. Thus, in this paper, we present a method of vibration control for the elevator rope, which is based on the nonstationary sliding mode control method using the input device with gaps. The effectiveness and robustness of the proposed controller are examined by numerical calculation that simulates input saturation, stroke limitation, gap-width expansion, and varying parameters, in the presence of model errors of the elevator rope. The results indicate effective vibration suppression and high robustness in the above cases except for the case of varying parameters.

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A novel grey model, called pseudo-GM(2,1) or PGM21 for simplicity, is developed to improve the prediction accuracy for a non-monotone sequence by modifying the GM(1,1) model with a remedial term. Since the remedial term consists of two development coefficients, it can be treated as a kind of second-order information, called the pseudo second-order information in this paper. With the remedial term, the PGM21 only costs a little higher computation time than the original GM(1,1) model; however, its prediction accuracy is highly increased. The important features of the PGM21 are demonstrated by numeric simulation results.

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In this study the global assumed mode method (GAMM) is used to analyze the dynamic behavior of a spinning Timoshenko beam subjected to a moving skew force with general boundary conditions. The moving skew force is usually caused by the frictional effect or the weight of the components. Considering three general geometric boundaries, i.e. hinged-hinged, clamped-clamped, and clamped-hinged, the system equations of motion are derived by the Lagrangian approach combining with the GAMM. The transient response of the system due to a moving skew force is evaluated by the Runge-Kutta method. The numerical results show that the lateral deflections due to the skew force for the hinged-hinged boundary case are smaller than those in the case of a clamped-clamped or clamped-hinged boundary. And the axial deflections due to the skew force are larger in the case of a hinged-hinged boundary.

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A vibration isolation system with variable damping and stiffness control is practical and has good performances. However, conventional devices of variable stiffness are usually complicated. A magnetorheological (MR) fluid damper only needs a small electric current to provide the magnetic field. It is easy to achieve variable damping with an MR damper in vibration systems. In this paper, two MR fluid dampers in series were used to achieve the variable damping and stiffness for the system. The passive, variable damping, variable stiffness, and variable damping and stiffness systems were investigated in experiment and theoretical calculation. The time and frequency responses to sinusoidal, sweep and random inputs showed that the system with a variable damping and stiffness had better properties.

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Most existing techniques which employ DWT (discrete wavelet transform) to detect servomechanism fault events are based on the analysis of measured motor current signals. However, the outcomes of these techniques tend to be unreliable when the motor suddenly accelerates or generates a very high output torque. Accordingly, to reduce the occurrence of false alarms, this paper develops a fault detection procedure based on the PICTO (PI-type closed-loop torque observer) structure and the DWT method. The PICTO structure is used to estimate the external load torque exerted on the servomechanisms. Utilizing the estimated data obtained from PICTO, a fault detection procedure is proposed which computes a “fault index” using DWT coefficients. This fault index enables the exact degree of the fault to be determined. The experimental results verify the effectiveness of the proposed fault detection approach.

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In recent years, a laminated rotor made of the insulated silicon steel laminates is increasingly adopted in the electrical machineries. While this laminated rotor offers good electrical performances, it is quite complicated to predict its stiffness as it is influenced by various factors such as material properties and shape of the laminates, characteristics of the insulation layer, lamination pressure and method of fitting. As it is difficult to model or define boundary conditions in the case of lamination pressure or fitting, the stiffness of the laminated rotor cannot simply calculated using conventional analytical method. Therefore, quantitative investigation on the influence of lamination pressure upon the stiffness of laminated rotor is highly required. In this study, natural frequency of the rotor is measured under various conditions of lamination pressure to investigate the influence of lamination pressure upon the stiffness of laminated rotor. It is found from the experiment that the natural frequency is increased with lamination pressure, and saturated near the 20% of the difference between the inner and outer diameters of the laminate. It is also found that the natural frequency can be controlled to 4-14% in the range of 1-10MPa of lamination pressure. The saturated value of the stiffness of laminated rotor is expected to approach to that of shrinkage-fitted cylinder having the same inner and outer diameters under the same assembly condition. It is expected that the results would be helpful to design generators or motors using laminated rotors.

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Based on the Lyapunov stability theorem, an adaptive output feedback variable structure tracking controller is proposed in this paper for a class of multi-input multi-output (MIMO) dynamic systems with mismatched uncertainties and disturbances. With an adaptive mechanism embedded in the proposed control scheme, the controller will automatically adapt the unknown upper bound of perturbations, so that the information of upper bound of perturbations is not required. Once the controlled system reaches the switching hyperplane, the state tracking errors can be driven into a small bounded region whose size can be adjusted through the design parameter. An application of flight control is given for demonstrating the feasibility of the proposed methodology.

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In this work we extent our recent results on the stability of rigid systems to cases involving flexible ones. We present closed form analytical expressions that describe the boundaries of the stability regions for digital PD control systems. This is obtained using a newly adopted approach based on the critical stability constraints of Jury test. The considered system consists of a single rigid and a single flexible mode. This simulates many practical systems such as antenna, space shuttle, and robot arm. The obtained closed-form stability criterion shows that the stability region is almost a right triangle in the gain space. The right-angle sides of the proposed triangle coincide exactly with two boundaries of the stability region. The hypotenuse of the triangle is found to well approximate the third boundary. An analytical expression is derived for the slope of the hypotenuse. This approximation results in defining the stability region using only two parameters which is convenient for practical applications. Case study is presented to show the practical usefulness of the proposed close-form stability criteria through investigating the control design of high speed flexible robot arm.

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In this work we extent our recent results on the stability of single-rigid/single-flexible mode system to cases involving damping. We present closed form analytical expressions that describe the boundaries of the stability regions for digital PD control systems. This is obtained using a newly adopted approach based on the critical stability constraints of Jury test. The considered system simulates many practical systems such as antenna, space shuttle, and robot arm. It is found that, the stability regions for damped flexible systems have three identifiable and distinguished topologies corresponding to three classes of damped system. The three classes are separated from each other by two surfaces in the three-dimension-space of the system-parameters. The stability region for the first class is almost a right triangle in the gain space where the third boundary, the hypotenuse, is described by the lowest root of a cubic equation. The stability region for the second class is clearly larger in size and the three roots of the cubic equation participate in defining the third boundary. In the third class, the stability region is further larger in size and the highest root of the cubic equation defines the third boundary. A peculiar situation is found where a stable system of the second class is possible with negative derivative gain. Numerical simulation is presented to verify this peculiar situation.

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The design of state feedback controllers and observers are proposed in this paper for a class of multi-input-multi-output linear systems with uncertainties and time varying delays both in states and control inputs. By using Lyapunov stability theorem, a sufficient condition is found for computing the state feedback gains of controllers and the gains of observers in order to regulate the closed-loop systems in spite of the existence of parameters variations as well as delays. This sufficient condition contains two inequalities, one of which is linear matrix inequality (LMI), which can be solved by utilizing the computer’s software package. The globally asymptotic stability of the closed-loop system is guaranteed if the solution which satisfies the proposed sufficient condition exists. An application is given for demonstrating the feasibility of the proposed control method, whose performance is also compared to an existing sliding mode control scheme.

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In this paper, we present a new observer, namely a cascade observer, for a general class of nonlinear SISO systems. Inspired by but different from a high-gain observer, the cascade observer features a cascade structure and adaptive observer gains. In doing so the cascade observer attempts to overcome some of the typical problems that may pose to a high-gain observer. As in the case of a high-gain observer, the cascade observer structure is simple and universal in the sense that it is independent of the system dynamics and parameters. It is shown that the estimation errors converge to zero and all the internal variables are globally uniformly bounded. Based on the cascade observer, an adaptive output feedback controller is designed for a class of SISO nonlinear systems represented globally by a nth-order differential equation. The output feedback controller has the same structure as a state feedback controller. Globally uniformly ultimate boundedness of tracking errors is achieved for the nonlinear systems with unknown parameters.

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In container yard terminals, containers brought by trucks arrive in the random order. Since each container has its own destination and it cannot be rearranged after shipping, containers have to be loaded into a ship in a certain order. Therefore, containers have to be rearranged from the initial arrangement into the desired arrangement before shipping. In the problem, the number of container-arrangements increases by the exponential rate with increase of total count of containers. Therefore, conventional methods have great difficulties to determine desirable movements of containers in order to reduce the run time for shipping. In this paper, a Q-Learning algorithm based on the number of container-movements for the material handling in the container yard terminal is proposed. In the proposed method, each container has several desired positions, so that the learning performance can be improved. In order to show effectiveness of the proposed method, simulations for several examples are conducted.

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The purpose of this report is to introduce and discuss about the design parameters for a segment of a tactile sensor reading one dot of a Braille alphabet. A sensor segment consisting of a piezoelectric (PVDF) film sandwiched between two elastic materials is designed. Experiments and simulations are used to define and examine the design parameters. With regards to the sensor structure, Free and Clamped boundary conditions are presented and the relevant equations containing the design parameters, e.g. “bending softness”, are derived. Applying different materials and thicknesses for layers surrounding the PVDF film, simulations are used to quantize the approximate values for each design parameter. The results show that the output of sensor is mostly dependent on the bending effect near the PVDF layer, and the structure encouraging more bending produces higher output. Finally, it is concluded that the real sensor has a structure which is between Free and Clamped boundary conditions, therefore design parameters are modified to compromise between the two cases and optimum values are presented.

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The dynamic behavior of the cylindrical shell with uniform flow is formulated by the finite element method. The dynamics of the shell is based on Donnell’s theory and the fluid in cylindrical shell is considered satisfying the Helmholtz equation. The effective thickness of fluid is calculated according to the circumferential modes and the frequencies. An estimation of the FRF (frequency response function) of the shell with taking into consideration of the coupled effects of the internal fluid is presented. These results are compared with the results considering fluid satisfying Laplace equation. The influence of fluid velocity on the FRF is also discussed.

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This paper identifies the method to control the vibration responses of a concrete viaduct model under impulsive force excitation. The frequencies and mode shapes of resonances of the bending vibration across the section can control the magnitude of the structure-borne noise radiation. A plastic hammer is used to excite the cement viaduct model at the centre and at the supporting edge position of the cross-section separately. The results of analysis using a Finite Element Method are confirmed by the experimental findings of the cross-sectional modes. The findings showed that the local modes are of two types: (1) Centre mode ─ the centre of top panel can move but the edge is fixed. (2) Edge (web) mode ─ the centre of panel is fixed but the edge (supported by web) can move. It is found that by supporting the machines on the edge, the center mode will not be excited but the combined mode of edge and center mode can give rise to significant noise radiation. A honeycomb panel with high resonance frequency is used to reduce the vibration transmission from this combined mode. The design can be used as an alternative to floating slab for reducing noise.

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Three-dimensional molecular dynamics simulation was conducted to clarify at an atomic level the flattening process of a high-temperature droplet impacting a substrate at high speed. The droplet and the substrate were assumed to consist of pure aluminum, and the Morse potential was postulated between a pair of aluminum atoms. By visualizing the analytical results, the processes of melting and solidification, temperature distribution, deformation velocity, and potential energy of atoms of the droplet were clarified. The following conclusions were obtained: (1) Transfer of the droplet atoms to the horizontal direction in the flattening process increases in proportion to the horizontal distance from the central axis of the droplet. (2) The increase of the flattening ratio of the droplet ends as soon as solidification of the droplet starts from the outside edge of the droplet. This behavior indicates the end of flattening.

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A novel approach to linearize nonlinearities commonly inherent in actuators is proposed in this paper. This approach solves the inverse of the nonlinearity without requiring its I/O relations as a one-on-one map, which is necessary for the current inverse-model method. By introducing the concept of the equivalent gain, the proposed method systematically finds the inverse model of the nonlinearity by solving a zero-finding problem. Discussions on the existence and uniqueness of the solution are given in this paper. A simulation example is presented to demonstrate how the task in finding the inverse of a complicated nonlinearity can be simplified by the proposed method. Experimental evaluations on a position servo system with conspicuous friction reveal that the dither-smoothed nonlinearities are still nonlinear, and compensating action like the proposed method is necessary for control systems using the dithering technology.

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In this paper, a proportional-valve controlled pneumatic X-Y table system is built to perform position tracking control experiments. The pneumatic system is subjected to external loads and parameter changes during the control. ILC (Iterative Learning Control) controllers are implemented in the experiments to show their ability to reject disturbances. The P and PD-typed updating laws with delay parameters are used respectively for the repetitive trajectory tracking control of X-Y table. Pre-saved control signals for different types of disturbances are also used to compare control performances. Experimental results show that under the disturbances, the PD-typed ILC controller is superior to the P-typed one and can effectively control the system to track the given circular trajectory.

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This paper addresses an approach for fast evaluation approach of correspondence uncertainty in 3-D vision metrology systems. The mathematic model of spatial resolution measurement area of a 3-D active vision system is developed from the calibrated system parameters. Using the derived model, error of correspondence matching between digital micro-mirrors device (DMD) and charge coupled device (CCD) camera is analyzed. Moreover, a performance index, expressed in terms of correspondence uncertainty, is used for evaluation of the upper and lower bound of resolution. In order to verify the proposed evaluation approach, a precision surface measurement system is established and calibrated. Our analysis shows that the upper part of the measurement area has the smallest correspondence uncertainty, which agrees well with the real physical arrangement. The variation of correspondence uncertainty within the measurement area is around 60.96%. Furthermore, based on the theoretical analysis of uncertainty bounds, an experimental measurement on gauge block was carried out and validated the method.

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In the paper, an asymptotic stability condition for a class of uncertain neutral systems with time-varying delays is considered. The parameter uncertainties under consideration are time-varying but norm-bounded. A new LMI-based delay-dependent criterion is proposed to guarantee the asymptotic stability of systems. Based on the results of this paper, no model transformation is used. Significant improvement for the obtained delay-dependent result has been demonstrated by numerical examples.

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The adhesion of a spider mite to a surface of a flat smooth plate is investigated as a model for micromachine parts to adhere to and move on such surfaces. The measurement of adhesive force is carried out under various conditions in which plate material, surface roughness of a plate and environmental humidity are differed. The adhesion mechanism is also discussed. Of the forces acting between a spider mite and a surface, one from dispersion interaction is the most dominant because (1) there is a high correlation between the adhesive force and the dispersion force component of surface energy with adhesive forces of 8.2µN for glass, 9.7µN for mica, 9.9µN for silicon and 12.1µN for gold, and because (2) high humidity and high surface roughness reduce the adhesive force. For strong adhesion based on work of adhesion, spider mites have tenent hairs with a bell-shaped end.

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Endothelial cells are known to change their shapes in alignment with the direction perpendicular to that of cyclic stretch. However, the mechanisms are still not clear. In this study, we developed a new cell-stretching device which allows continuous observation of cyclically stretched/relaxed cells. Using this apparatus, morphological changes of single cells in response to cyclic stretch (1Hz, 10%, 2 hours) were visualized and analyzed. The data showed that there were two major patterns of morphological changes of ECs, depending on their initial shapes. While ECs with round shapes at the initial state changed their shapes to become more elongated in a direction perpendicular to that of stretch, cells oriented and elongated in the stretch direction at the initial state changed their shapes to first become rounder and then elongated to align perpendicular to the stretch direction at the second step. These results suggest that cell retraction as well as elongation is important in the stretch-induced endothelial morphological changes, and that the elucidation of the mechanisms of the morphological changes requires studies of cell retraction, elongation, and their coordination at the single-cell level.

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In this paper, we show an approach to elucidate the free flight of an insect using a simulation. We modeled a fly, Drosophila, by using aerodynamics, body dynamics, and control theory. The modeled virtual insect performs free flight in virtual space generated by a computer. We simulated the free flight of a virtual insect having two dimensions and two degrees of freedom. The flight pass and flight velocity of the virtual insect during a free flight were calculated by Newton’s equations of motion. The aerodynamic force generated by the flapping motion of the virtual insect was estimated by using the blade element theory. An optimal regulator theory was used as a control law. The flight pass from the initial position to the target position and the wing motion was obtained from the results of the free flight simulation of the virtual insect. We can presume the wing motion of an insect in free flight by using the flight simulation of a virtual insect. These results have suggested that the approach based on the simulation is effective in elucidating the free flight of an insect.

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In this study, ground reaction force (GRF), absolute symmetry index (ASI) and coefficient of variation (CV) of fixed, single-axis and multi-axis prosthetic ankle assemblies were investigated by biomechanical evaluation of above knee amputees. In the experiments, 37 normal male volunteers, two male and two female Above Knee (AK) amputees GRF data were tested with fixed, single-axis and multi-axis prosthetic ankle assembly. A gait analysis was carried out to derive the ratio of GRF to weight as the percentage of total stance phase for ten points. The results showed that fixed-axis ankle assembly was superior to other two ankle assemblies for forwarding and braking forces. Multi-axis ankle was relatively superior to other two ankle assemblies for gait balancing and movement of the mass center. Single-axis ankle was relatively superior to the other two ankle assemblies for CV and ASI of GRF.

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In automotive industry there is a growing concern for the total economy of a manufacturing system throughout its life-cycle. In order to decrease its affect on product cost a better utilization of the manufacturing system is necessary. Product family analysis is a means to group products with common manufacturing aspects and analyze its manufacturability in a possible or existing manufacturing solution. The aim of this research is to provide support for product family analysis by enabling reasoning about resource’s capability, i.e. what a resource can do and how well it can do it.

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This paper deals with a work support system that helps novice workers to execute and learn tasks efficiently. In order to realize this system, the interaction process between workers and the support system is discussed. Radio frequency identification (RFID) system is applied for setting flexible interaction processes in consideration of worker competency. Also, a software simulator that measures the capacity of human memory and learning is used to formulate a guideline for the interaction design. Finally, an experiment on the work support system in actual assembly work is conducted. As a result, all subjects were able to complete their tasks without error, even when they attempted the work for the first time, and to learn a series of tasks by the practical operations using the support system. This result confirms the effectiveness of the work support system.

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A simple process of fabricating a three-dimensional nanostructure on a silicon surface was investigated in this study. The silicon surface area irradiated by focused ion beam (FIB) was selectively etched in HF, whereas the non-irradiated area was scarcely etched, and consequently, a concave nanostructure was fabricated on the irradiated area. To control the depth of the nanostructure, the depth dependence on ion irradiation parameters was investigated. As a result, it was found that the depth of the irradiated area can be controlled by changing ion irradiation parameters, such as dose and ion energy. Under a low-dose condition, the irradiated area was scarcely etched, due to the formation of an amorphous layer on the interior of silicon. Subsequently, it was etched in KOH to evaluate the mechanism of this phenomenon. In addition, the surface roughness dependence on ion irradiation parameters was investigated. Finally, three-dimensional nanostructures were fabricated on the basis of these results, suggesting that this method is a novel three-dimensional nanofabrication method.

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This paper deals with the influence of the quantity of oil supply in hobbing with minimal quantity lubrication (MQL) of cutting oil, compared with that using dry cutting and flooded oil, in terms of flank wear, crater wear and finished surface roughness, for various types of coating films of the hob. Experiments were carried out using a fly tool. The results obtained are summarized as follows. (1) The flank wear obtained with a quantity of oil supply of only 1mL/h showed almost the same value as that obtained by dry cutting, when using the TiN- and (Al, Ti)N-coated tools. However, it is a result of great interest that flank wear increases with increasing quantity of oil supply, and the largest value was obtained when the oil was flooded. (2) The crater wear and finished surface roughness with the MQL system are smaller than those using dry cutting and flooded oil. (3) The quantities of oil supply of 1mL/h to 15mL/h in the MQL system are suitable for hobbing in terms of reducing flank wear, crater wear and finished surface roughness.

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In order to understand the phenomena of electrical discharge machining (EDM), the characteristics of transition arc plasma in EDM were investigated. The arc plasma was directly observed with a high speed video camera. In addition, to learn more about arc plasma expansion, plasma temperature was measured by spectroscopy. The arc plasma temperature was obtained by measuring the radiant fluxes of two different wavelengths from the arc plasma and applying the line pair method. Furthermore, a new expansion model for EDM arc plasma was proposed based on the observations, and validated by comparing experimental and computed results of the discharge crater.

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Aerostatic spindle systems have been widely used in many machine tools due to their low heat generation and high-speed capability. To meet industrial demands for higher accuracy and higher productivity, such spindle systems have recently become important as the kernel component in an ultraprecision machine tool. In this study, therefore, thermal deformation control for aerostatic spindle systems has been proposed considering heat balance in an objective spindle bearing system. In the proposed method, the temperature of supply air is controlled by monitoring that of exhaust air to minimize the thermal deformation of the spindle. The performance of the thermal deformation control system developed has been evaluated through a series of actual experiments.

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The paper presents the model of procedure and the results of forecasting the operational reliability of conventional grinding wheels applied to automated production systems. The forecasting was issued on the basis of Young’s modulus of these tools obtained from preoperational acceptance inspection. The model was verified during the process of internal grinding of bearing rings. Investigations were applied to 100 ceramic grinding wheels with the same characteristics. As a criterion for operational reliability were assumed: the grinding wheels radial wear Δ_rs, the maximum spindle power demand P_c and the arithmetical mean deviation of the roughness profile R_a. It was demonstrated that the operational reliability of tools under investigations was strictly interrelated the modulus E. Therefore; it can be used as a prognostic criterion for reliability of the system including these tools.

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The crosshead bearing in large two-stroke diesel engines operates under severe lubrication conditions, because the bearing oscillates within a small angle at a low speed and is always subject to a high downward load. The recent trend towards more compact engines with increased output raises the bearing specific load, thereby causing the lubrication severity to increase significantly. Thus it is very important to improve the load carrying capacity of the crosshead bearing. In the present study, experiments using a dynamically loaded bearing seizure test apparatus were carried out to clarify the influences of the clearance ratio and the oil-groove geometry on the load carrying capacity. The electrical resistance of the oil film was also measured to evaluate the extent of the oil film formation. The major results are: (1) A decrease in the clearance ratio is effective in enhancing squeeze action on the entirety of the bearing pads, thereby improving the load carrying capacity. When the clearance ratio becomes too low, however, the ability to form an adequate wedge film is degraded, causing the load carrying capacity to decrease; (2) A significant improvement in the load carrying capacity can be expected, because incorporating the taper geometry on both sides of the oil-groove promotes a thicker oil film; and (3) A taper geometry with a subtended length of 5 degrees and a taper angle of 0.1 degree produces the maximum load carrying capacity.

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