In this paper, the results of experimental and analytical studies of the performance of a new electrostatic separator for plastic mixtures for recycling are presented. The separator is of the free fall type and consists of four cylindrical electrodes. Prior to separation, plastic mixtures to be separated are tribocharged. When the charged particles are fed into the center of the space between the four electrodes, they are attracted to the space between the electrodes with voltages of polarity opposite to the particles' charge because of Coulomb force. Therefore, the plastic mixtures can be separated as a result of the different positions to which they fall. Separation tests were performed on a sample containing 50% polystyrene and 50% ABS plastics. Plastic particles obtained from crushed plastic plates were used. It was found that the separation efficiency depends on the electric potential difference between positive and negative electrodes, tribocharging time, the rotation speed of the tribocharger and the length of the electrodes. It was also found that it is possible to obtain a high purity and a high recovery rate for a binary plastic mixture.

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The purpose of this paper is to propose one analytical method to make stochastic floor response spectra in order to easily estimate the dynamic characteristics of secondary system such as piping, equipment and so on, under the stochastic non-stationary excitation and model uncertainty. Applying the transition matrix method with state space to the secondary system mounted on main structure, the non-stationary standard deviation of absolute acceleration response relating to the secondary system is obtained under the assumption of no structural uncertain properties. Then, finally, in order to obtain the statistical results of response in consideration of model uncertainty, through combining the extreme value theory, FOSM(First Order Second Moment) method and ACO(Ant Colony Optimization) algorithm, the floor response spectra can be stochastically derived. This proposed floor response spectra may be called the Stochastic Floor Response Spectra. The analytical results are compared with those by Monte Carlo simulation, and show the accuracy and efficiency.

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This paper presents modal descriptions of structural intensity for flexural vibration on flat plate. The modal forms of the structural intensity are expressed by superposition of the product of weight coefficient and cross-modal function which can be estimated by two natural modes. The characteristics of the weight coefficients and the cross-modal functions are discussed by using numerical analysis. It is shown that the cross-modal functions can be classified into two types of distributions - power transmission and non power transmission types -. It is also shown that the non power transmission type cross-modal function can take no propagating power. At last we demonstrate that the derived modal form of the intensity can be useful to explain the difference of the structural intensity under two different excitation frequencies. The demonstration would suggest that the modal expansion can be effective for designing the structural intensity distribution.

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Uncomfortable vertical vibration, which is caused by walking and traffic vibration occurs in long spans on lightweight floors and pedestrian decks. In order to suppress such vibrations, Tuned Mass Damper (TMD) is most commonly used. Usually strokes of TMD are limited by rigid stoppers in order to avoid collisions with control targets. In case of large earthquakes, the stroke of TMD increases, so that TMD collides with the stoppers. Therefore it does not exhibit enough vibration control performance. In order to solve this problem, this paper proposes a TMD with buffers. This TMD has buffers, which suppress the stroke of TMD. The buffers are installed beside the TMD, and gaps between buffers and the TMD are a few millimeters. Thus, in case of environment vibration, collisions with buffers do not occur, and the TMD retains as good vibration control performance as conventional one. In case of large earthquakes, the TMD collides with buffers, so that strokes of the TMD are suppressed and the vibration response of target structures is mitigated. In this paper, the selection of parameters of the TMD with buffers such as gaps and specification of buffers was conducted by simulation analysis. In addition, an experimental model of the TMD with buffers was made. Then vibration control performance is investigated by vibration experiment. As a result, it was confirmed that the TMD has a good performance of vibration control and stroke suppression.

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Ultrasonic technique is an indispensable diagnostics to evaluate internal conditions. The conventional ultrasonic technique using a wave property, such as a reflected wave, wave speed, attenuation of amplitude and frequency spectrum is, however, not effective in some cases. In this study, we propose to use an instantaneous frequency of the ultrasonic pulse. The instantaneous frequency expresses a transition of the frequency of the ultrasonic pulse, so that it is sensitive to a slight variation of the ultrasonic frequency. The effectiveness is demonstrated through an experiment on adhesive strength of epoxy adhesive, which is controlled by curing process. The conventional ultrasonic technique is difficult for an evaluation of this adhesive strength. On one hand, the instantaneous frequency of an ultrasonic pulse, which passes through the adhesive layer, certainly distinguishes the difference of the adhesive strength. It is also shown that the adhesive characteristics pertaining to their strength are modeled as damping coefficients, which is demonstrated through a simple simulation of one-dimensional ultrasonic wave propagation.

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Ultrasonic motors have some features; small size, lightweight, low speed-high torque, silence, and large holding torque. However, due to the friction drive and the need for switching about rotation direction, it is not easy to realize the fast response without overshoot. To overcome these issues, this paper heuristically proposes some practical control methods. At first, P/PI changeover for the position compensator is introduced to realize overshoot-less responses. Next, it is shown that the input shaping filter, which is introduced to improve the shape of positioning waveforms using the conventional input filter, desirably influences the settling time. Moreover, Bang-Bang control is implemented in the position loop to realize the fast positioning. Finally, combined control for the above techniques, i.e. fusion control scheme, is examined under the conditions with and without load torque. As a result, most fast positioning is realized in case that P/PI changeover, Bang-Bang control, and CW/CCW changeover with dead zone are mixed. Then successful positioning waveform is realized.

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1/f noises, the power spectrum density (PSD) of signals inversely proportional to the frequency, have been observed in various types of physical and physiological systems; e.g. current and heart beat. 1/f noise is suggested to be generated by superimposing stochastic processes. Among stochastic processes, autoregressive process is suitable for analyzing physical and physiological systems in that the autoregressive process is time-discrete. A time-discrete model is suitable for analyzing those systems because those systems are observed in time-discrete manner as well. However, it is obscure whether 1/f noises are generated by superimposing those autoregressive processes. In this study, first order autoregressive (AR(1)) processes were superimposed with varied the process parameter and a driving noise. As a result, PSD of superimposed time sequences was inversely proportion to the frequency when the process parameter and a driving noise were a uniformly distribution and white noises, respectively. This result suggests that 1/f noises could be generated from the superimposing AR(1) processes when the process parameter is distributed uniformly.

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In this study, a method using optical contactless displacement sensors to evaluate vibrational stress was proposed. As sensors, light-emitting diodes were used. The values measured with multiple displacement sensors were used in the proposed method to approximately calculate deformation shape, that is, curvature radius which occurs within a relatively narrow area of anything to be measured, and then the vibrational stress was obtained using the curvature radius. The vibrational stress was compared with the stress obtained by the conventional method using strain gauges, and the applicability of the proposed method was verified. Furthermore, the measurement accuracy was discussed from a sensitivity analysis with regard to the signal-to-noise ratio during the measurements.

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The touch-sensitive screens have intuitive operability, thus these touch-sensitive screens have become popular with a variety of devices in late years. In particular, it has come into widespread use in small devices; cellular phones, music players, PDA and so on. These small devices have the feature that it is possible to carry them around easily. There is also tendency that we operate these devices by one hand. Therefore, it is pointed out that the screen interface appropriate to one-handed operation is required. However, there is not knowledge enough to use for interface design of touch-sensitive screen. In this study, for the purpose of defining the condition of switch size and shape is easy to operate, we evaluated influence of switch size and shape on their error rate and pointing time. The subjects of this experiment are 15 healthy male. They were asked to operate on touch-sensitive screen under 35 conditions of switches. The results show that there is an appropriate switch size that improves the usability of portable touch-sensitive screen. Furthermore, it is found that error rate, pointing time and subjective easiness of operation become worse when the switch shape is vertically long or horizontally long.

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Creative activities, such as painting and music, are one source of satisfaction and fulfillment for people with disabilities. However, some individuals with disabilities cannot satisfactorily enjoy such activities due to involuntary movement. In this study, we developed a drawing assist system for patients with cerebral palsy of the tension athetosis type, who experience involuntary movement. It has been difficult for the assist system to distinguish involuntary movement from voluntary movement. We designed a variable filter to attenuate involuntary movement on the basis of characteristics of synthesized velocity with respect to involuntary movement. Our system enabled drawing based on the participant's own senses and motor control, even when experiencing involuntary movement.

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For high-variety low-volume manufacturing, parts are processed by the handwork because of the problem of the production cost. However, when a precise finishing process is required, the process by handwork has the problems not only a processing error occurs but also required processing accuracy cannot be secured. To clear up this problem, we develop the fixture robot with parallel mechanism and propose assist control for accurate finishing process considering a material removal rate (MRR). We realized high accurate finishing process by means of controlling pressed force and feed speed to keep MRR constant. In the end, the effectiveness of proposed method is shown by the experiment and user's test.

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In this study, three different types of delamination (partially-debonded regions in the adhesive layers) were artificially introduced into carbon fiber reinforced plastic (CFRP) laminated beams and then both of experiments and numerical analysis using finite element method (FEM) were applied to evaluate their vibration damping properties under cantilever-type fixtures. The experimental measurements showed that, when delaminations were introduced into the specimens, in general, the first bending mode frequencies decreased and the modal loss factors increased. For the purpose of explaining the experimental observations especially in terms of damping, distributions of transverse shear strain energy and contact pressure on the internal debonding surfaces were numerically examined by FEM analysis.

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This paper describes a simple and cost effective countermeasure to prevent carbody vibration of railway vehicles due to rotation of wheelset(s) with small mass imbalance by applying a displacement-dependent rubber bush in traction links. The displacement-dependent property is realized by introducing a small gap between the rubber and the inner fixture, and transmission of the excitation force from bogie to carbody is isolated by the gap. Excitation tests using a full-scale test vehicle to verify the vibration isolation performance, and running stability testing with a bogie are carried out in the rolling stock testing plant at Railway Technical Research Institute (RTRI). Then a series of running tests on a commercial line is conducted and the effectiveness of the displacement-dependent rubber bush has been confirmed.

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A novel misfire detection method for stationary internal combustion gas engines is presented. The main aim of the proposed method is focused on statistical detection of misfire as a precursor of malfunctions of ignition systems. Use of conventional exhaust temperature sensor installed in each cylinder is proposed. Characteristic waveforms which appear in the measured sensor output are analyzed and classified if they are signs of misfire or normal fluctuations. The key factor of the proposed method is an algorithm for discrimination of waveforms. Empirical if/then rules and dynamic time warping are compared as waveform recognition methods. The former has a merit of low computational cost, whereas the latter can be designed and employed rapidly using an appropriate template wave. Data collected for three years from an actual engine in operation is used for validation and evaluation of effectiveness of the proposed method.

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This paper proposes a procedure for determining compromising solutions so as to support the decision making of designers for ergonomic design problems. The comprehensive evaluation of multiple muscle loads are formulated as a multi-objective optimization problem, and the optimum solutions of each participant are obtained. The regret is defined as the maximum difference from the objective function values of each participant's optimum solution, and the compromising solution is defined as a design variable vector that minimizes the regret. Determination of the compromising solution is formulated as a min-max problem, and the proposed method presents the trade-off between the number of intended participants and the regret. The proposed method is applied to the design problem of seat height for sit-to-stand movement. The seat height is the only design variable, and surface electromyography of elector spine, rectus femoris, tibialis anterior, and gastrocnemius were measured when participants stood from a chair. The ratio of the maximum voluntary contraction (MVC) was used as the indicator of muscle loads. The response surfaces of the %MVC of elector spine, rectus femoris, and tibialis anterior were approximated by using the radial basis function network because of their statistical significance. Result from the optimization, it is found that the comprehensive evaluation of the three muscle loads probably expresses the sense of the participants more precisely than the use of any of the three muscles. In addition, the compromising solutions are almost same (between 430 to 440 mm) even though the number of intended participants decreases.

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Recently Taguchi method is used to decide optimum processing conditions with narrow dispersion for robust design. In this method, several control and noise factors are selected and used in the later experiment. Control factors are equal to the design factors. Noise factors are occurred for the error of function on the product. All combinations using all control factors are compressed by an orthogonal table. Then the experiment or the CAE analysis with influence of noise factors is performed by the orthogonal table. At last, the average and the standard deviation regarding all combinations using all parameters are calculated for the SN ratio. Then most of users write the effective figure of the control factors and zealously search the combination of the control factors for large SN ratio. A product using the combination isn't influenced by noise factors. In this study, the new method for evaluation of influence regarding control factors using inverse analysis of the Taguchi methods is developed and evaluated. SN ratio and sensitivity in the final results of the Taguchi methods consist of the average and the standard deviation. The average and the standard deviation regarding each lever of each control factor is calculated using the final results of the Taguchi method. Both the average and the standard deviation have the several influences of the noise factors. Therefore most designer can understand the influence regarding each lever of each control factor under environment of several noise factors. We have made the software and evaluated by the experiment using a paper craft (Kami-koputa). It is concluded from the result that (1) the new method using inverse analysis of the Taguchi methods is developed and (2) the software developed was effective for evaluation of influence regarding control factors.

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As developing countries gain strength in manufacturing technologies, developed countries have to shift their course in producing highly value-added products. Artistic products, different from conventional industrial products, are considered to be one of high value-added products, which contain a number of skills of experienced operators. However, artistic products in developed countries are requested to be automatically produced by means of efficient machine tools with multifunction and powerful CAD/CAM systems. Such a manufacturing way may be named 'Dexterous Machining'. The Dexterous Machining is an idea to take skills of experienced operators into machining technology. As the first step, a new machining method and a procedure of a complicated shape with a nested structure are devised and developed in the study to establish a CAM system for the Dexterous Machining. The CAM system contrives an efficient machining method by use of a special jig and a support pillar. A machining experiment is conducted to confirm the validity of the devised machining method and the developed CAM system. As a result, it is confirmed that the developed CAM system is effective to create the nested structure.

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This paper proposes a unique test piece for evaluating the machining performance of five-axis machining centers. A cone-frustum specified by NAS 979 standard has been used as a test piece over 40 years. In this paper, a truncated square pyramid with a half apex angle of 15 degrees is proposed as a test piece for checking the machining performance instead of the cone-frustum. The truncated square pyramid has to be installed on the slope of a fixture which is mounted on the rotary table of the machining centers in order to conduct the machining test under simultaneous five-axis control. Thus, two kinds of fixtures with different mounting angle were prepared for the experiment. The profiles of four side surfaces finished by milling were measured on machine table by an LVDT sensor which is fixed on the spindle head. The contour form of the side surfaces of the test pieces were also measured on a coordinate measuring machine. It is found from both measurement data that the straightness of each side surface, the squareness between adjacent surfaces as well as parallelism can be evaluated by on-machine measurement, and also pitch errors and backlash of tilting rotary tables can be checked. This test method gives much more information compared with the cone-frustum test method.

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NC data for machining the cone-frustum by means of five-axis machining centers with a tilting rotary table are analyzed in detail. The cone-frustum is machined by using a milling cutter at simultaneous five-axis control for inspecting the machining accuracy. However, the NC data have to be changed corresponding to the setting position of the workpiece on the rotary table. Thus, the moving range and velocity of each axis are analyzed by changing the apex angle and center position of the cone. It is found from the analyzed results that the larger apex angle gives the larger moving range and the higher velocity to all axes. When the center position moves along the Y-direction, every reversal point independently appears on a circular path. Therefore, it is recommended to offset the center position of the cone frustum along Y-direction to give the large moving ranges and the high velocities to the axes.

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Plastic film, formed as wound roll, is stored and transported under the various temperatures which can be different from the winding temperature. This temperature change affects the in-roll stress variation over time. As a result, it could lead to wound roll defect such as blocking or wrinkling. It is extremely important to theoretically estimate the in-roll stress in order to prevent the defect efficiently. In this study, a winding model for the unsteady thermal stress, considering entrained air effect on heat conduction in radial direction is presented. Air layer is formed between the wound films due to air entrainment during winding. On the winding model, the film is treated as equivalent layer combined with the air layer. In addition, the equivalent thermal conductivity, density and specific heat are taken into account the variation of contact between the wound films. Experimental verification result states that the predicted values correspond well to the experimental values. From a parametric study, it is shown that the air layer tends to influence on the heat conduction and the thermal stress if thermal conductivity of plastic film is high and the thickness of the air layer is thick.

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The energy supply and demand balance being very unstable in Japan today, utilization of renewable energies as alternative for fossil fuels is an important issue. In this study through experiments in wave power energy conversion teaching materials for learning were developed, interest and concern were heightened and efforts were made to bring awareness of the issues closer to home. We were able to verify the students' gaining of a deeper understanding of energy problems and grasping of energy conservation concepts through the experiments in the classroom activities. The force of the wave is converted into the motion of the steel balls and the electricity is generated. This contrivance which the steel balls move quickly even in the case of the small wave has been made the equipment. The lessons practice was carried out using this teaching tool for junior high school students. In the experiment lesson, its results verified educational effect, showing that students gained higher awareness of energy issues and also were able to effect concrete instances of energy conservation that they were able to do themselves.

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The impulsive riveting method can join the sheets without drilling as well as disjoin easily the jointed sheets. The joints made by the method have high joint strength and the deformation of the joints is also small. However, the equipment for the impulsive riveting is large in order to utilize the impulsive energy and the control of the impulsive energy is very difficult. Therefore, miniaturization and simplification of the equipment are necessary for the practical application. In this study, the punching rivet method that the sheets were joined by pressing the rivet without drilling was proposed and applied to the joining of cold-reduced carbon steel sheets. The deformation and the strength of the joints made by the method were examined in comparison with those of the joints made by caulking and the impulsive riveting method. The effectiveness of the proposed method was clarified from the experimental results..

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The authors have reported that the micro wavy surface formed by machining combined with laser heat treatment have higher static coefficient of friction compared with the surface finished by polishing or cutting. Therefore, this study was carried out to clarify the surface formation mechanism in order to control micro wavy height and the influence of lubricant viscosity on static frictional force. In practical use, high viscosity lubricant is used in wet brake to prevent oil leakage. At cutting after laser heat treatment, when the higher thrust force was, the higher micro wavy height was obtained. Thus, decreasing cutting speed or increasing feed rate, the obtained micro wavy height became higher. The static coefficient of friction of surface finished by polishing was decreasing with lubricant viscosity. This tendency was also seen at micro wavy surface. However, the static coefficient of friction of micro wavy surface was constantly higher than polished surface regardless of lubricant viscosity.

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The effect intra-articular administration of the hyaluronic acid (HA) for the treatment of osteoarthritis knee joint has been widely recognized. However, the efficacy of mechanical tribology function of HA as a viscosupplementation to joint lubrication has not yet been confirmed. To examine in vivo the effects of enhancement of tribology function of joint lubricant for the treatment of osteoarthritis, animal experiment was performed. Experiment osteoarthritis of the both of knee joints of three rabbits was induced by meniscsectomy and cartilage defects. These animals were subjected to monthly intra-articular cartilage injection of high viscous polyethylene glycol (PEG) to one side knee joint (another side was not injected as a control knee), and were sacrificed at 3 month after operation. The extracted knee joints were evaluated macroscopically and histologically. As a results, the PEG injected knees had a tendency to demonstrate less damage of articular cartilage compared with the control group. This finding indicated that the development and addition of mechanical lubricant for the preventing of articular cartilage wear could have potential to be one of effective treatment for arthritis.

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