Distributions of velocity and concentration of turbulent gas jets, ranging from helium to carbon dioxide, with various densities with respect to ambient air are measured using particle image velocimetry and laser-induced fluorescence methods. The turbulent transport of the nozzle fluid is directly investigated to analyze the distributions of nozzle-fluid concentration and its vortex motion. The results indicate that self-similarity exists between profiles of scalar flux and Reynolds stress along the radial direction. Furthermore, several sub-grid scale scalar-flux models for large eddy simulation are discussed. Based on the scattering plots of the model values of sub-grid scale scalar flux with respect to the measured values, the characteristics of each model are similar for all of the density conditions. In addition, the Favre-averaged scale similarity model performs well for a wide range of densities.

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Simultaneous separation and transportation of works with various coefficients of friction by means of elliptical vibration was demonstrated. As for transportation by elliptical vibration, works move right or left, or stop, according to the phase difference between the horizontal and vertical vibration. Since transportation characteristics change with coefficient of friction, works with various coefficients of friction can be simultaneously separated and transported by controlling the phase difference. Experimental results show, first, that works of the same shapes and sizes can be separated according to the material they are composed of and, second, that plain washers and electronic parts also can be separated according to the different shape of their face and reverse sides. Moreover, the optimal driving conditions for separation were determined. That is, the speed of separation and transportation is highest when the vertical vibration amplitude was equal to the jump limit. In addition, the dispersion of transportation characteristics is reduced when the horizontal vibration amplitude was increased.

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It is important to obtain the stress frequency distribution caused by service loads in order to estimate the fatigue life of welds on vehicle truck frames. Although this distribution by service load is obtainable from vehicle running tests, it is difficult to estimate it at the design stage. Accordingly, we examined the characteristics of stress frequency obtained from past running test data, and analyzed them in conjunction with analysis on the effects of running conditions, including distance, speed and payload. The study results will be used to estimate stress frequency distribution at the stages of design or modification in train line with operating conditions.

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Lost motion is a major disturbance that affects the contouring accuracy of NC machine tools. Although NC machine tools with plain bearing guideways are capable of high alignment accuracy, their lost motion sometimes varies according to motion conditions such as position, velocity and moving length. Conventional backlash compensation with a constant parameter applied to the lost motion causes contouring error due to inadequate compensation. This paper presents a model of a two-body system with a position-dependent spring and motion-condition-dependent friction that exhibits varying lost motion, and an adaptive compensation method for the lost motion is derived from the model. A tuning method for the compensation parameters is also proposed. Stiffness of the position-dependent spring is calculated from the specifications of mechanical parts, such as a ball screw, bearings and a coupling. The varying friction is estimated by a disturbance observer. Contouring accuracy in a circular test of NC machine tools demonstrates the improved performance enabled by the proposed method.

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In running cars or trains, passengers are often getting sleepy. We focus on this physiological phenomenon. If a machine can reproduce this phenomenon, it is feasible to put insomnia patients or infants to sleep without any harmful effects. This will bring extreme benefit for insomnia patients or parents of babies. The purpose of this study is to elucidate the sleep-inducing factors of running cars or trains, and the final goal is to develop a sleep inducing machine which reproduces the mechanical environment for sleep. For the first step, this study investigated the relationship between sleepiness and vibrations on several trains. The sleepability of each train is discussed by the ratio of sleeping passengers (RSP). High RSP trains can be recognized as comfortable to sleep. The acceleration profile of trains is analyzed by FFT and jerks. The results suggest that the comfortable train has mainly low-frequency (under 2.0 Hz) vibrations with particular fluctuation. Small jerk also contributes the sleepability. A prototype sleep inducing machine is tested with several subjects. The questionnaire survey indicates that near 1.0 Hz excitation is the most comfortable vibration for sleep. This result supports our hypothesis.

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In this study, we propose a method to improve source localization accuracy in a wind tunnel test by using a microphone array. On the basis of a model of the acoustic path passing through a free shear layer, we installed the microphone array adjacent to the main flow to avoid refraction and dissipation in the free shear layer. Flow-induced noise due to the interference with the main flow is reduced effectively by calculating the cross spectrum between the respective outputs of two pairs of 2-D microphone arrays. The effects of these techniques are verified by the acoustic performance test using a standard source device with wind exposure. It was found that this calculation method is effective even at a uniform wind velocity of 300 km/h and enables acoustic measurements adjacent to the main flow. Accurate noise source localization can be achieved by installing the microphone array along an extended line from the sidewall of the wind tunnel nozzle. Compared with the conventional microphone array installed outside of the main flow, the estimation error of convection distance due to the expanding free shear layer is improved from 60 mm to approximately 10 mm at a main flow velocity of 300 km/h.

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The present study is a fundamental approach to reveal the minute fluctuating pressures on three-dimensional blade surfaces of a basic propeller fan. Because, among the concerning physical quantities, the unsteady pressures on the rotating blades give us useful information for the fan flow and its sound-noise level. The authors correct the centrifugal-force effect, the gravitational-force effect and the other leading-error effects for accurate measurements of the minute pressures using a measuring technology developed by the authors (Hirata et al., 2009). As a result, we show the Reynolds-number effects and the spatial distributions on the blade of both time-mean pressure and pressure-fluctuation intensity.

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The accident occurrence rate at waste disposal facilities is high in comparison with that rate of other industrial facilities. For example, the rate of accidents per 1 million hour operation of waste disposal facilities is about 10 times higher than that rate of overall industries. Thus, lots of efforts were given to reduce the accidents at waste disposal facilities, in the past. Some of the efforts were changing the design of the facilities to increase the safety and some were updating the O&M manuals. Our study focuses on systematic approach to continuously develop the O&M level. We developed O&M diagnosis system which consists of selected internal third party inspection considering the past experience of each facilities (O&M, troubles, accidents and so on). In addition to the safety problem, most waste disposal facilities are facing the problem of shortage of the money. Especially, that problem is heavy for municipal wastes disposal facilities which are owned & operated by municipalities. Thus, waste disposal facilities have to be efficient and economical. We developed management system by using targeted value like performance index of the facility and targeted value management system is combined with O&M diagnosis system. We applied O&M diagnosis system including targeted value management system on Teshima waste treatment project and the effect is examined. The result of experiments will be shown in the paper.

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The present paper describes the investigation of an active feedback noise control system in an enclosure surrounded by rigid walls. A large number of operations is required for active control in a rigid-walled sound field because lots of acoustic paths between multiple sensors and multiple secondary sources can exit. The rigid-walled sound field can be expressed by the superposition of a large number of orthogonal acoustic modes. It is expected that single-input single-output(SISO) model can be achieved for each mode independently using the modal decomposition and generation techniques and that various previously developed SISO control methods can be used. Therefore, I propose an active control system with SISO H^∞ controllers to suppress multiple mode amplitudes independently based on the modal decomposition and generation techniques. In the present paper, the characteristics of the proposed system to control four modes are verified numerically and experimentally. The obtained results show that significant noise reduction in practical use can be achieved without mode couplings.

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In this paper, a LiBr/H₂O absorption refrigerator was fabricated and experimentally studied. The refrigerator was driven by solar heated water with an 85°C of designed temperature. The condenser is water-cooled at the design temperature of 32°C. The refrigeration capability was designed to be 2.3 kW at 7°C. A detailed experimental study was conducted on the thermo-siphon generator, the most important component of this type of refrigerator. The performance of the refrigerator was presented in terms of COP and refrigeration capacity. An analysis was made on the relationship between refrigerator performance and working conditions of thermo-siphon generator. The experimental results show the designed parameters (e.g. refrigeration capacity and refrigeration temperature) were well achieved. But the refrigeration capacity decreased dramatically as the temperature of hot water decreased down to the temperature below 85°C.

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As tube banks are set in a duct in a boiler and a heat exchanger, the resonance phenomenon or the self sustained tone are generated due to the interference between vortex shedding and acoustic characteristics of the duct. It is necessary to know the resonance frequency of the duct, namely sound speed, for avoiding any trouble that may arise. In general, it is said that the sound speed decreases in the duct with tube banks and an evaluation formula is given. However, this formula is obtained to apply to the perpendicular direction of the flow. We wanted to know whether this formula would be able to be applied to the flow direction and to various arrays of patterns or not. In this paper, the applicability limit of this expression is discussed by using FEM analysis and experiments.

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In Japan, the declining birthrate has resulted in a social problem, namely, the shortage of a young labor force. One of the ways by which this issue can be resolved is by establishing social surroundings in which parents with a baby are able to work comfortably. In this study, a system is proposed that can give comfort and peace of mind to a baby by transmitting the heartbeat rhythm of its parent to the baby through the Internet and simulating the transmitted heartbeat rhythm in a doll held by the baby or in a pillow. Moreover, the system also gives peace of mind to the parent by transmitting the baby’s heartbeat rhythm to the parent and simulating the transmitted rhythm by means of a portable simulator like a wristwatch. An evaluation experiment is carried out to confirm whether a baby responds well to the heartbeat rhythm of its mother, which is simulated in a pillow, and that the mother can recognize the heartbeat rhythm of her baby by using the portable heartbeat simulator. The results revealed that when a baby is interested in the simulated sound, it prefers the simulated heartbeat rhythm of its mother rather than an artificial heartbeat rhythm with a constant period and the condition that the stimulation stops. Therefore, it is confirmed that the proposed system can give peace of mind to both a baby and its parent.

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The "urban heat island phenomenon", whereby the temperature of urban areas comes to be high in the shape of an island compared with the suburbs, is said to be one of the modern issues of urban environmental problems. It has been thought that the main causes of the urban heat island phenomenon are an excess of heat energy in urban areas, such as an increase in the urban population accompanying the development of rapid economic activity, an increase in artificial buildings, a reduction in green tracts of land, and an increase of greenhouse gas. Although heat island solution techniques, such as green roofs, green walls and heat shield coating with high reflectiveness, have been studied and put into practical use, there are still problems to be solved with these techniques, such as reducing the cost of execution and maintenance. As one solution to these problems, the use of "reed screens" as a heat shield material has been considered. The "reeds" used as a raw material for "reed screens" have important functions in connection with the conservation of nature, such as the effectiveness whereby they absorb nutrient salts, the prevention of eutrophication, the formation of nursery grounds for aquatic life forms, and the absorption and fixation of carbon dioxide. Periodical harvesting is required for reeds to maintain these functions. However, since there is little practical usage after harvesting, sufficient harvesting is not performed. Therefore, a very important subject has been to consider how reeds can be utilized after being cut. Accordingly, if reed screens are utilized as heat shielding and heat insulation materials on the roofs of buildings, the practical use of the reeds after harvesting will be greatly promoted. The purpose of this research is to show how a new circulation system using "reeds" can be built as a solution for the urban heat island phenomenon which reduces cost and becomes maintenance-free. In this paper, the solar radiation shielding effectiveness in the daytime in summer and the heat insulation effect at night in winter were checked in a survey whereby "reed screens", a natural vegetation recycled material, were installed on the rooftop concrete surface of a building. Furthermore, the paper shows the result of collecting basic data on heat island mitigation effects in sensible heat flux and upward long-wavelength radiation, which influence the space outside a building.

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The authors developed PEM fuel cells consisting of thin separators with the thickness of 0.8mm. The paper investigates the dependence of cell performance on the gas diffusion layer (GDL) thickness, hydrophobic characteristics of GDL, binding contact pressure, channel depth, temperature and water content in the working gases. The result shows that the pressure losses increase inversely proportional to the third power of the cannel depth and it increases significantly for the channel depth less than 0.2mm. The best performance was obtained with a GDL which has relatively lower hydrophobic characteristics. It was also shown that better performance was obtained with relatively thinner GDL for the shallow channels with the depth of 0.3mm used in the experiment. The paper also proposes a simple estimation of liquid water amount in the cell, which may be useful for the water management control.

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Pulverized waste printed circuit board powder is a complex mix of organic epoxy resin, glass fiber, and several different metals. The aim of this study was to investigate the feasibility of separating the components of the powder and then efficiently recovering the metals by magnetic separation. The organic resin was first decomposed by pyrolysis in an inert atmosphere. The pyrolysis gas was subject to chemical analysis, and the toxic components were successfully trapped. Magnetic and nonmagnetic components in the residue were then separated by magnetic force.

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Cavitation induced vibration and consequent erosion of pipes are potential damaging factors in the piping systems of power plants. In order to prevent them, we previously developed a cavitation detection method using accelerometers or microphones placed outside pipes during operation which compares RMS (root mean square) values of sensor outputs upstream and downstream from an orifice (i.e. pipe throttle). However, this method can detect only the stage of developed cavitation. Therefore, in the present study, in order to confirm the effectiveness of the cavitation detection method, we evaluated incipient cavitation erosion on pipe walls using impulsive force detectors and aluminum erosion specimens and compared the cavitation detectable conditions with the erosion occurrence conditions. Results obtained by the impulsive force detectors were insufficient due to weak forces, but the cavitation number σ at the incipient erosion was obtained from observation of erosion pits on aluminum specimens. The cavitation detection method could detect cavitation in the region of σ ≤ 0.9 and erosion pits occurred in the region of σ ≤ 0.8 . As the results, we confirmed that the cavitation detection method could be effective to monitor and prevent cavitation erosion on pipe walls.

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Impact damper systems are used to reduce the vibration of a lightly damped resonant primary system. The impact damper consists of an impactor and a container. The container is attached to the mass part of the primary system. The container mainly consists of two walls, and the impactor is placed inside the container. And since the impactor is free to move in the container, the impactor collides with the walls. When the impactor collides, some of the vibration energy of the primary system is momentarily converted to kinetic energy of the impactor. That is, impact damper system is damper which utilizes this energy conversion by impact phenomenon. We compared the damping characteristics in an impact damper system between a translating impactor and a rotating impactor and found that the rotating impactor is superior to the translating impactor. Then, with the aim of improving the damping characteristics of the rotating impactor, we proposed that an eccentric mass be added to the rotating impactor and confirmed that the damping effect improves because of the eccentric mass. Next, we calculated the mechanical energy of a vibration system having an impact damper and investigated the mechanism behind this improvement in damping characteristics due to the eccentric mass. In particular, we classified the impacts that occur between the impactor and wall into three types and examined the change in energy of the primary vibration system immediately after such impacts. In this way, we clarified the mechanism behind improved damping effect due to the addition of an eccentric mass.

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The purpose of this study is to clarify the fundamental features of NO_x formation in oxy-coal combustion. The pure effects of various factors related to oxygen concentration, flame temperature and flame pattern on NO_x formation are investigated by experimental and theoretical analysis, resulting in the following conclusions: (1) In oxy-coal combustion (CO₂/O₂ atmosphere), the emission of fuel-NO_x increases with O₂ concentration. (2) The flame pattern changes from a detached flame to an attached flame with the increase in flame temperature. (3) During oxy-coal combustion, the gasification reaction between CO₂ and carbon on the surface of char particles occurs more vigorously than during combustion in air. (4) The single particle model for estimating NO_x emission is applicable to the detached flame pattern. This implies that in the case of the detached flame the pulverized coal burns with a structure of premixed flame.

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A study on the environmental impact of a short haul aircraft has been performed. Main target of this study is to investigate the effect of flight mission characteristics on total emissions over the lifetime of an airliner, with a major parameter being aircraft annual utilization. The study has been completed using ‘Hermes’ aircraft performance model and ‘Turbomatch’ gas turbine performance code, both developed in Cranfield University and applied on a typical 185 passenger, 2500nm range aircraft. The results show that such an aircraft is expected to produce ∼10000 times its weight in CO₂, during a 20-year operating life. The environmental assessment of the effect of utilization strategy and type of mission comes to add to the understanding of aircraft contribution to greenhouse gases at top level strategic route planning phase. As a result, this paper provides an alternative method for estimating the environmental impact of a modern airliner, showing that when optimizing for utilization, conventional expressions of aircraft efficiency, such as fuel per passenger-miles, can be misleading. Such approach can be of value in near future, where CO₂ taxation is expected to come to force and affect, therefore, strategic route planning.

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Room pressurization is an important ventilation design technique for preventing airborne contaminants in biological clean rooms. To design an air-conditioning system that controls room pressure, an analytic method is needed, that predicts and estimates the change in room pressure and duct pressure, since they influence each other. In this paper, we present a new technique for predicting room pressure and duct pressure. In our technique, this pressure propagation mechanism is replaced with an equivalent circuit network by considering the air volume as electrical current, the lifted pressure by the fan as a battery electromotive force, and the friction loss as an electrical resistance. The change in room pressure is represented as the equation of resistance to air leakage. By using this technique, Kirchhoff's Voltage Law is applied to the duct network and the pressure calculation can be solved without many variables at the junctions. In addition, combining the resistance coefficients for elements carrying the same degree of air volume simplifies the duct network. Therefore, convergence performance is improved and the computing time can be shortened. By comparing it with experimental results, we verify the validity of the method. Using this technique, the air-conditioning equipment can be evaluated under dynamic usage and the specification of the control devices can be optimized. The effectiveness of any new ideas for maintaining a stable system response can be examined.

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The prove position of a hot-wire anemometer in Fig. 1 and the corresponding descriptions in text were wrong. Also, a driving-shaft length of “0.043 m” in Table 1 was wrong. The correct length is “0.430 m.” The correct figure and table are attached behind these errata.

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