[in Japanese]

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With decline in the birthrate, labor shortage of young generation becomes social problem. In order to solve this problem, it is necessary to establish the social surrounding in which parents with the infant are able to work feeling easy. Then, authors have been proposed the system giving comfort and peace of mind to the infant in the nursery by transmitting the heartbeat rhythm of the working parent through Internet and reproducing it in the doll held by the infant. In this study, the system giving comfort and peace of mind to the parent by transmitting the heartbeat rhythm of the infant through Internet and reproducing it on the arm of parent is proposed. And the portable heartbeat rhythm reproduction equipment like a wrist watch is produced experimentally using a small solenoid. In addition, evaluation experiment is carried out to confirm whether the transmitted heartbeat rhythm gives the good effect to the infant. As the result of 1 examinee, it is clarified that the infant prefers the heartbeat rhythm of the mother.

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There have been a number of reports on active noise control (ANC). However, conventional ANC using voice coil loudspeaker promises attenuation only at targeted local points. Then ANC using the parametric speaker as a control source is discussed. The parametric speaker exploits the nonlinear interaction of finite amplitude ultrasounds in the air. The characteristics of parametric speakers have already been reported by a number of researchers. However, investigations of simulations or experimental results of ANC using a parametric speaker are sparse. This paper addresses a control effect of feed forward ANC using parametric speaker as a control source. The control effect is more than 20dB by ANC using parametric speaker as a control source at 1000Hz. Neighboring affects of both conventional control source and parametric speaker as a control source used to ANC in the free fields is shown by numerical analysis and experiments.

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Various structual measures against vibration and noise were taken in a training ship, Osima Maru. However,an unpleasant sound persisted in the messroom, where crews take their breaks. In order to reduce the noise, active controllers were investigated and one of them, the phase corrected filtered error LMS algorithm, is corrected to satisfy causality on its update processes. Some of them were preconditioned using the inverse of the plant because their convergence rates are limited by the dynamics and coupling within the plant response. The algorithms were compared under the same conditions to investigate differences in their properties and also corrected to satisfy the causality of their update processes. Simulations for acontrol system were introduced using plant responses measured from a loudspeaker toa microphone in the mesroom inside Oshima Maru. After investigating the convergence speed in various gradient descent adaptation algorithms, the results were integrated with the actual plant response and applied to the active control of ship interior noise.

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This paper concerns the minimization of total acoustic power radiated from noise source. First, the authors focus that the acoustic power of the control source under the optimal condition for minimizing total acoustic power become zero. Then, the authors propose a method employing an active noise control in order to minimize the total acoustic power by investigating the acoustic intensity distribution pattern of the control source and characteristics of control speaker. This power reducing performance is verified on the basis of theoretical estimations and experiments.

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This paper deals with the active control method to reduce sound radiated from a vibration symmetric structure into a free field using error signals derived from structural sensing. It has been found that by taking advantage of the symmetric properties of structural modal functions, "radiation clusters", which is an orthogonal contributor with respect to acoustic fields, can be defined. The validity of radiation cluster control for sound radiation from a simply supported rectangular plate into a free field is numerically investigated.

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In 3-dimensional sound field, it is di cult to control noise in whole area. Instead of whole area control, the controlled area can be followed to people in that field by new approach proposed in this paper. In the proposed algorithm, FTF algorithm that has fast converging property is introduced to a direct adaptive algorithm which does not need an error path characteristic. A numerical simulation is carried out with a sound field that the error path changes during control. From the results of the simulations, the e ectiveness of the proposed algorithm is shown.

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In this paper, active noise control was carried out applying to the three dimensional space. As an analysis acoustic field, examinee sat on the chair, put error microphones on the both ears. The case where noise came from the front was set up. In the analysis acoustic field, it experimented, the control effect at the time of head movement was investigated, and the present problem was shown. In addition, in the analysis acoustic field, when the examinee uttered voice during control, the echo was occurred. The Control system for solving the problem was proposed, and the validity was verified by the simulation.

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"Soundscape" is defined as "an environment of sound as it is perceived and understood by the individual, or by a society, and as such depends on the relationship between the individual and any such environment". There are three fields of activities which are developed through the concept of soundscape ; research and studies, education, and design in a broad sense. The last field is characterized by the fact that not only is the the conventional design method, that is "plus design" available, but also the method of conservation, "zero design", and the method of abatement or restriction, "minus design". Also thinking of soundscape makes us aware of the "richness of quietness". Soundscape ideas therefore illuminate a new field of environmental design and concern.

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This paper describes how the evaluations of sound quality of car interior noise are affected by the visual scenery and by the seat vibration exposed simultaneously with the variations of brightness and vibration level respectively under the real running mode. Subjective experiments were conducted using the car simulator set in the sound proof room and evaluations were conducted using a ten key box as an input devise for the subjective responses with the 7 category scale. The attributes used are powerfulness, unpleasantness and booming sensation for obtaining their trade-off levels in SPL with the variations of brightness and vibration level. As a result, the evaluations of powerfulness, unpleasantness and booming sensation increase with the decrease of brightness of the visual scenery and with the increase of vibration level of the seat vibration. In general, the effect of increase in the evaluations is more with the increase of vibration level than with the decrease of brightness.

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Nowadays, guiding chimes are being hastily installed at ticket gates of railway stations according to the governmental guideline about movement support using auditory signs. However, this guideline does not indicate any definite standards on their installation, thus some situations appear where the chimes do not work well due to inappropriate installation. This study aims at clarifying the present circumstances around the chimes by way of hearing to the visually handicapped and on-site investigation of sound environment in a dozen of stations. The former describes a variety of their usability, specifying the characteristics of the chimes ; the latter demonstrates the volume of the chimes, the audible areas and the audibility at significant points in the stations.

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Experiments were conducted to evaluate the economic value of the sound quality of machinery noise emitted from vacuum cleaner and hair dryer. In the experiments concerning vacuum cleaner, stimulus cards of twenty-five kinds of vacuum cleaners were presented to participants. Each card gave participants details of the characteristics of each vacuum cleaner in respect to six attributes such as manufacturer, price, noise level (dB) and sharpness (acum) of the machinery noise. In the attributes of noise level and sharpness, three levels were set up (64, 59, 54dB and 2.46, 2.21, 1.96 acum, respectively). In the explanations of these experiments, the machinery noises were not presented to participants. 50 participants evaluated their preferences for each vacuum cleaner. Rating values were applied to conjoint analysis. From the obtained partial utilities of each level in the "machinery noise" and "price" attributes, the economic valuations for a 5dB in A-weighted SPL and a 0.25 acum in sharpness were examined. The estimated values differed from those obtained in the previous study, in which the machinery noises were presented to participants in the explanation concerning the "machinery noise" attribute. In the present study, the explanations concerning the "machinery noise" attribute might affect the estimated values.

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The aeolian tones generated from the tapered cylinder were investigated for several inclined angles experimentally. The tapered cylinder was inclined from -40 to 40 degree. It is obtained some interesting results in relating to the aeolian tone and the unsteady flow characteristics. The aeolian tone is large not at the zero angle, but at negative and positive angles. When the side of the large diameter is set downstream at the negative inclined angle, the aeolian tone becomes large compared with the positive angle. The wake vortex generates even at the large inclined conditions. The aeolian tone is fairly low at zero degree compared with the large inclined angle. It is indicated that the aeolian tone is governed not only with the strength of the flow fluctuation in the wake, but also with the position of the rolling up to the wake vortex.

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In the present paper the attention is focused on the effect of cavity length in in-line tube banks with small tube spacing on acoustic resonance which occurred in the two-dimensional model of boiler. As a result, we found many peak frequencies of sound pressure level with different Strouhal numbers, mainly about S_t=0.15, 0.26 and 0.52. The acoustic resonance of S_t=0.15 was generated in in-line tube banks with cavities of tube pitch ratio of 2.11〜3.44. The velocity fluctuation and periodicity of the vortex shedding were the most intense inside of cavities of tube pitch ratio of 2.78〜3.44. It was easy to generate acoustic resonance in this case.

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A tunnel entrance hood decreases the pressure gradient of compression wave generated by a high-speed train entering the tunnel, and thereby, reduces the "micro-pressure wave" radiated from the distant portal. While the effect of the entrance hood has been marked, it becomes necessary to extend its length with costly works, in order to raise the entrance speed of trains. Therefore, we have been developing a new type of tunnel entrance hood equipped with pipes on its roof, which could decrease the pressure gradient of the compression wave with smaller hood length than conventional entrance hoods. We performed model experiment to investigate the function of pipes for controlling the pressure gradient waveform and reduction effect of the maximum pressure gradient. As a result, it is shown that the pipes equipped on an entrance hood could delay increase of the pressure and decrease the pressure gradient further.

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The FBG cantilever sensor was used for detection of flow separation. This optical sensor detects a shift of the wavelength to the reflected light corresponding to the amount of strain. We had researched on the sensing of direction to flows. As a next stage, this sensor was installed at trailing edge of a flat plate, and has investigated on the performance of the sensor and the characteristics of the flow separation. As a result, this sensor could catch the changing of the flow direction and the periodic fluctuation to the flow separation.

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By using two set of optical microphones developed in AIST, aerodynamic sounds generated by flow separation around an airfoil was measured. First, airfoil implementation of the optical microphones is described. Second, acoustic characteristics of the microphone and detection of separation sound are discussed. Finally, through optical intensity analysis, applicability of the microphone for detecting separation is examined.

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Recently, in railway, it is requested to reduce the rolling noise that has a great part among the trackside noise. Therefore, we have developed a new type of rail noise isolating material for the purpose of reducing the rolling noise. This material is consisted of two laminated layers of ethylene-propylene rubber foam and steel sheet laminated with vibration damping layer, and muffles the whole area of rail web and flange. Characteristics of this material are lightweight, compact and to be easy to install. According to the impact test to evaluate this material's vibration and acoustic characteristic, we confirmed that this material could reduce vibration and generated noise when it was installed to rail. Additionally, by the noise measurement of actual trains along the railway line, we recognized the noise reduction of about 2dB at the neighborhood of rail.

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For the conventional narrow-gauge railway lines, the noise generated by railway vehicles mainly consists of rolling noise and traction-motor fan noise. The rolling noise relatively has greater contribution to the total noise than before by the introduction of new traction-motor fan. In this paper, the vibratory characteristics of wheels, which is important factor of the rolling noise have mainly focused on and investigated by both field tests and numerical analyses. In the field test, the modal parameters for three types of wheel are obtained. By varying the wheel web geometry, the dependence on the vibratory parameters is examined through the numerical analyses. Through the studies, it is found that the web geometry has a great influence on the radial modes. The thickness of the web affects 1-nodal-circle axial modes. The tyre region is important for O-nodal-circle axial vibration with higher order modes.

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This paper studied a new concept of a quieting wheel cover which can attenuate tire road noise. BEM simulations predicted that ρ c boundary at the circumferential surface could reduce radiated noise from a tire to 90°direction by 2〜4dB and acoustically soft boundary could reduce it by more than 10dB. These results were proved by speaker tests. A sound absorbing wheel cover could attenuate tire road noise by 2〜4dB at the frequency higher than 630Hz in which almost perfect sound absorption is established. And a resonator wheel cover could attenuate it by 6dB at 1250Hz band. Finally a drum test showed that a sound absorbing wheel cover could attenuate it by 5dB at any speed.

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Effects of fixed hub cone and rotating hub cone are equipped jet fan, and power cable on the noise characteristics of fan were investigated in this research. The noise of jet fan is equipped fixed hub cone is higher than that of rotating hub cone. Because in the former, the turbulent flow due to eight struts which are supporting fixed hub cone flows into the rotor. By attaching the case which made the aerofoil form the power cable, the width of wake which flows in to the rear rotor can be made narrow, the fan noise can be reduced.

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This paper describes monitoring of corrosion wastage of piping systems based on structural deformation in order to reduce a trouble about pipe systems in process plant. New method of measurement and monitoring by PPP-BOTDA (Pulse-Pre-Pump Brillouin Optical Time Domain Analysis) and inverse structural analysis were verified by examination. It is useful to operation and maintenance to monitor thickness of pipe continuously under plant operation.

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National criteria for the assessment of low frequency noise annoyance in Sweden, Denmark, Netherlands, Poland and U.K. were reviewed, and the basic concepts were compared. The Experience from these countries in applying the criteria was also reviewed, and a common difficulty of these criteria in practice was showed. Japanese criterion, "Reference values of mental and physical discomfort" was compared with these criteria, and the advantages and the problems were discussed for future improvements in the criteria.

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Pressure fluctuation occurs in an oil pressure pump in the nature of the machine. It becomes a cause of a vibration and a noise of a building where the oil pressure pump are set because the pressure fluctuation gives a fluctuating force on floors and walls of the building. So it is important to reduce the vibration and noise from an environmental point of view. A side-branch is often used to reduce the pressure fluctuation because of its simplicity and its effectiveness. However the long side-branch is necessary to reduce the low frequency noise because of the relation f=c/4L. Where L is the side-branch length. In this paper, the noise reduction effect of the side-branch with the finite impedance end is examined theoretically and experimentally. As a result, it was clarified that the side-branch with the finite impedance end gives the reduction effect in frequency range lower than that of the rigid end.

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Psychological responses and permissible limits of 20 subjects under intermittent rattling noise of a fitting were measured. A subject sits in front of the fitting with glass plates and answers questionnaires for psychological state in/after exposure of intermittent rattling noise from the fitting exposed to low frequency noise. The fitting rattles 10s cyclically with silent time. The values of "loud", "can't tolerant as living room" and "can't tolerant as bed room" increase as a duty factor of rattle time in a cycle time increases. Permissible limits were measured by L_<Aeq 5s> of rattling noise adjusted by subjects themselves. The permissible limit decreases according to duty factor. A calculated L_<Aeq> from L_<Aeq 5s> is almost constant regardless of duty factor.

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It is reported that not only an audible noise but also a low-frequency noise is radiated from a high-speed train toward a way-side area in an open section. The observed the low-frequency noise, which is defined here as the noise of below 80Hz including the infrasound of below 20Hz, consists of hydrodynamic pressure variation around the nose and tail part of the train and low-frequency acoustic pressure wave by aerodynamic sound sources around the train as well as vibrating surfaces of a viaduct structure. We use an acronym PF (Pressure Field) for the former phenomenon, and PW (Pressure Wave) for the latter. In the past, we measured the wayside low-frequency noise in a fully open section, however the causes of the PW still remained to be fully clarified due to lack of sufficient data. Hence, we have measured the PW in the wide range of the train speed of 150〜400km/h. From the obtained characteristics of spectra, distance attenuation and velocity dependency, the major component of the PW in the far field is found to be aerodynamic sound emitted from the train, in a high-speed region of over 350km/h.

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The low frequency noise is not clearly defined but is generally taken to mean noise below a frequency of about 100 to 150Hz. Noise at frequencies below about 20Hz is sometimes referred to as infrasound and this type of noise presents even greater difficulties in its measurement and assessment. The objective of our study is to suggest practical means of reducing the low frequency noise emanating from the opening of soundproof houses. This paper describes an experimental study on the alleviation of low frequency noise by the opening built in Helmholtz resonators.

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Aerodynamic sound source of bogie section of high speed trains is studied to reduce aerodynamic sound, numerically. Three-dimensional unsteady flow around a bogie section is solved by voxel method and aerodynamic sound source are visualized by Lighthill-Curle's theory. Simulated results show the separate flow at the leading edge of the bogie section attaches to the surface of bogie components, and the inner region of bogie section becomes a dead water region. Visualization of aerodynamic sound shows that the strong sound sources are generated at the trailing edge of the bogie section, and at the cover of bogie component, where the unstable shear layer hit. Results show that it is necessary to control the large-scale flow separations to reduce aerodynamic sound of bogie section.

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The aim of this investigation is to clarify generation mechanism of aeroacoustics feedback of rearview mirrors for automobiles. To understand relationship between flow field and tonal noise, wind tunnel experiments were carried with a backward-facing step and small bump. The experimental results showed that the strong tonal-noise was observed when the height of the bump was almost equal to 40% of height of the boundary layer. Correlation in terms of velocity fluctuation and tonal-noise was high at the edge of backward-facing step. Strong correlation was also observed just behind the small bump. The disturbances from the small bump therefore seem to be the seeds of the tonal-noise. In order to understand the effect of edge shape of backward-facing step, acoustic field around the edge of step was calculated. The acoustics filed depended on the edge shape of the back-step. The result of wind tunnel experiments showed the tonal-noise was not observed in the case of the back-step with large round-edge.

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For further speed-up of Shinkansen, reduction of aeroacoustic noise generated by a pantograph has been an important subject of discussion. In particular, a panhead significantly influences the aeroacoustic characteristics of the pantograph. The dipole noise generated by the panhead can be evaluated by using Howe's vortex sound theory from flow field quantities obtained by numerical simulation. This paper describes the method to evaluate contributions of dipole noise source around the panhead toward the dipole noise observed at the far field. Visualizing the contributions of dipole noise source around the panhead can shows the dipole noise source structure around the panhead.

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Predicting high frequency sound field in a cabin by using numerical analysis is essential for efficient acoustic design of noise reduction, but is difficult because it's a large scale problem of large number of elements. In this paper, fast multipole boundary element method (FMBEM) which has been developed as technique to reduce the computational time for large scale problems is applied to simulation of sound field in a simplified cabin model. And effect of the shape of sound field and the number of elements in a cell at the lowest level on computational time is examined.

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Calculating noise with a high degree of accuracy is necessary for estimating the radiated noise induced by the electromagnetic force from a motor. The accuracy of the calculation can be improved by modeling the motor in detail, but that increases the number of degrees of freedom in the model and has limitations due to increased CPU time. We analyzed models that give accurate of electro-magnetic noise in the range of the frequency band where the noise occurs. We compared the calculations based on stator core models with and without teeth ; the number of degrees of freedom in the model without teeth was less than that in the one with teeth. We found that the calculation based on the model without teeth was as accurate as the one based on the model with teeth. Moreover, we confirmed that, of the radial and circumferential electro-magnetic forces, the radial electro-magnetic force was the dominant source of electromagnetic noise.

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An improved TSP (time-stretched pulse) method for measuring an oblique incidence absorption coefficient is proposed. The value of the absorption coefficient obtained by this method is equivalent to the value obtained by the TSP method, in which the reflected sound is extracted from the difference of the pulse arrival time, in high reproducibility and short measuring time. The proposed method can measure the oblique incidence absorption coefficient for a shallower angle than the TSP method. In this method the sound that comes directly from the speaker is measured separately in a free sound field. Therefore, there is no need to separate the arrival time between the direct sound and the reflected sound from the surface of the specimen. The validity of this method was ascertained by comparing the numerical solution of the boundary element method and the solution of theoretical analysis, even in the case of an incident angle shallower than 45 degrees for the official specimen size (4×5m).

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Sapporo Plastics Recycling Co., Ltd. (SPR) and Rekiseikouyu Co., Ltd. had developed and put to practical use of the liquefaction plant for municipal waste plastics including PVC and PET, and maintaining a high rate of making to oil, and waste plastics oil making technology to have done considerable results though the processing of making to these liquefaciton plants had passed six years or more since it began to have driven. The feedstock recycling that returns the generation light oil of these liquefaciton plants as a raw material in the oil refinery (Japan Energy Corporation) is started that becomes the first in the Japan in April, 2004, and this also continues the stability driving well. In addition, progress to the technology that does the feedstock recycling can expect the waste plastics cracked oil, and the prospect that the feedstock recycle by the simple waste plastics liquefaction plant towards in the future is realizable by this will be acquired.

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There is a large amount of wet biomass in Japan ; however, it is difficult to utilize them as energy for retained water. Digestion is efficient process to produce energy from them ; however, sludge and wastewater treatment after digestion is expensive. Recently, mixed digestion of sewage sludge and kitchen waste is suggested in sewage treatment plants, where wastewater after digestion can be treated efficiently by advantage of aeration tank capacity. For efficient use of biogas and residue, biogas should be utilized as auxiliary fuel in dried and carbonization equipment or in electric power plants, or as boiler fuel for heating of digestion tank. On the other hand, residue should be dried and carbonized as solid fuel. This paper reports calculated material and heat balance of case studies for such various systems.

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VPSA (Vacuum Pressure Swing Adsorption) process that can remove harmful matter such as hydrogen sulfide, siloxane and carbon dioxide in digestion gas is developed in order to maintain soundness of power generation facilities in the system sewage sludge digestion gas is collected, and to utilize in power generation. The field examination (1〜10M^3N/h scale) by true digestion gas was executed in the sewage sludge treatment plant. As a result, more than CH_4 concentration 95%, more than methane recovery 95% are achieved with more than hydrogen sulfide removal rate and more than siloxane removal rate 99%.

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We have newly developed the total Biomass Solid Fuel Usage system which is Pyrolysis coke production system using indirect heated kiln from sewage sludge, and Pyrolysis Coke use for fuel of co-firing in coal power plant. This system contributes to the reduction of greenhouse effect. We conducted demonstration test of pyrolysis coke production system. The test result shows a safety and stable operability. We also evaluated and proved that pyrolysis coke is utilized for a solid fuel of co-firing in coal power plant. This paper describes outline of pyrolysis coke production system, result of demonstration test and Evaluation of Pyrolysis Coke Fuel of co-firing in coal power plant.

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EF steel dust, an industrial waste, it is usually treated by Wealtz kiln etc. and then zinc, lead and other valuables will be separated and recovered and simultaneously large quantity of clinker will be formed from the furnace. Clinker consists mainly of iron but metallic form is low therefore hardly to use it as iron raw material. In this study, some practical tests for gravity and magnetic separation and concentration of metallic iron had been carried out in an industrial scale. Finally, it was confirmed that effective iron enrichment is possible and then recycling of iron to EF should be realized as a steel making raw material. Now industrial plant is under planning.

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Prastics recycling by a coke-oven from waste plastics into chemical materials has been developed to solve the problems of waste plastics and as a step toward protect the environment from global warming caused by the reduction of CO2 emissions. Waste plastics are discarded containers and wrapping from households mainly, and there is the thing which food residue sticks to inside. We will bring in harmful insects in the Works with waste plastics. This paper proposes some methods for exterminating harmful insects.

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Plastics recycling by the coke-oven from waste plastics to chemical materials has been developed to solve the problems of waste plastics and to protect from the global warming by the reduction of CO_2 emissions. But waste plastics containers and packages has much volume and occupies coking chamber space. So it occurs decreasing coke production and makes this process uneconomical in present business environment. To promote plastics recycling more economically and effectively in this process, it is necessary to make it into high-density plastic briquette. In order to get briquettes density higher, this paper proposes some methods for removing moisture to heating to high temperature.

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Recently, the construction of the waste management system corresponding to the recycling society is needed. The construction of Best Available System is hoped for in all respects of the municipal waste from the exhaust stage to recycle or final disposal stage with its quantitative assessment. Then, the municipal waste process assessment software that the municipality is able to use easily was developed as a tool for the BAS proposal in this study. In addition, the assessment example with the developed software was shown, and the effectiveness was realized.

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In recent years, occurrence of the accidents in the general waste disposal facilities is reported from many fields. Then, we surveyed the bulky waste disposal facilities, and made the accidents and troubles data base to prevent the accidents. We developed the Security and Safety Design Analysis Method built in accidents and troubles data base to find the potential risk from the design phase of the facilities. Moreover, we upgraded it so that calculating the risk from the damage situation by deciding the default value concerning the amount of damage referring to insurance might become possible. We assessed the safety of the bulky waste disposal facilities with the Security and Safety Design Analysis Method. As a result, the explosion in the ripper generated by the combustible gas such as the gas spray cans mixing is the most risky.

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Teshima waste disposal business has been done as a solution of the industrial waste illegal disposal problem happening in Teshima, Kagawa Prefecture since 2003. The role of the watch of the business is requested by the resident living in Teshima and Naoshima. On the other hand, disclosing a useful relevant information for the understanding of the business is needed in Kagawa Prefecture who is the entrepreneur. Both of information matched to the progress of the business. co-creation system is thought to be necessary by such correspondence. We have aimed to practice it what we can do as an engineer. Life Cycle Assessment (LCA) of the entire Teshima waste disposal business was evaluated. The environment and the economy of the Teshima waste disposal business were measured.

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