The wayside noise around a tunnel portal of Shinkansen mainly consists of both the noise radiated from the tunnel portal and that from an open section. This suggests that the wayside noise around the portal tend to be greater. In past studies, the model to predict the noise around the portal for Shinkansen was proposed, in which both the road traffic noise prediction model (ASJ RTN-Model 1998) and Shinkansen noise prediction model are combined. The predictions with this model tend to be overestimate, although the overall trends are well-predicted. In this study, the laboratory experiment using the scale models has been carried out in order to investigate the contribution of both the noise radiated from a tunnel portal and that from an open section to the total wayside noise. It is found that, at the measuring points near the portal, the noise from the portal has much greater contribution to the total noise. And, it is also found that the noise is screened due to the vehicle at the open section.

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In order to control Shinkansen wayside noise, various measures along the Shinkansen lines have been made. Around a tunnel portal, the wayside noise tends to be greater. In past studies, the prediction models and countermeasures for the wayside noise around the tunnel portal of Shinkansen line have been investigated. It has been found that (1) the Shinkansen wayside noise around the tunnel portal consists of both noise from open section and noise from tunnel section and (2) the noise is reduced properly by putting sound absorbing materials on an inner wall of tunnel entrance hood. In this paper, in order to develop the prediction model, an acoustic model test were carried out. It was found that the noise radiated from the tunnel portal was affected by vehicles. Then, the prediction model was improved by considering the screen effect due to vehicles in the open section, and the validation work of the model was made.

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Measurements and theoretical studies related to wheel/rail noise have been carried out widely and thoroughly. The wheel/rail noise from 250 Hz to 4 kHz significantly influences wayside noise along railway lines. However, when a train runs on a gently curved track, the noise due to wheel and rail vibrations above 10 kHz significantly contributes to the total wayside noise. A recent field test on the wheel/rail noise above 10 kHz showed that, during train passage through a curve, the wheels on the outside rail are the dominant noise source, and after it has passed, the outside rail is the predominant on the curved section of narrow-gauge railway line. In this paper, on a curved section of a high-speed railway line, the contribution of the wheel/rail noise above 10 kHz to wayside noise is investigated in field tests and static experiments with a shaker excitation. It is found that, during the passage of a train, the wheels on the outside rail are the dominant noise source.

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Measurements and theoretical studies related to wheel/rail noise have been carried out widely and thoroughly. The wheel/rail noise from 250 Hz to 4 kHz significantly influences wayside noise along railway lines. However, when a train runs on a gently curved track, the noise due to wheel and rail vibrations above 10 kHz significantly contributes to the total wayside noise. A recent field test on the wheel/rail noise above 10 kHz showed that, during train passage through a curve, the wheels on the outside rail are the dominant noise source, and after it has passed, the outside rail is the predominant on the curved section of narrow-gauge railway line. In this paper, source localization related to the wheel noise above 10 kHz is carried out through field tests with a directional microphone on a curved section of a high-speed railway line. It is found that the wheel noise above 10 kHz is mainly generated by the outside leading wheel of each bogie.

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Under sleeper pads have been installed to reduce the vibration from sleepers to substructures. In recent years, the under sleeper pads molded by foam rubbers have been examined for applying them to the ballasted track. The elasticity of foam rubber materials can be easily changed by modifying the foaming ratio, and the thickness of under sleeper pads can be reduced. Because foam rubber deforms with compression of the porous cells in itself, the contact area between the under sleeper pad and the surface of the ballast is locally increased according to the roughness of the ballast. Thus, it is expected that the load and vibration to the ballast layer is absorbed and reduce the ballasted track settlement. In this paper, vibration and noise level near the track were measured in the presence and absence of under sleeper pads with foaming rubber. As a result, it was confirmed that the vibration level to the ground was reduced because of the installation of the under sleeper pad and noise level was similar even if the under sleeper pads were installed.

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In this study, we considered how to extract the vehicle body vibration mode affecting largely to the road noise in cabin. Through the experimental mode analysis, we firstly obtained vibration mode shapes of the vehilce body model. However, not all vibration modes are excited at the operational condition and gave large influence to the interior noise. We subsequently applied principal component (PC) model of operational transfer path analysis (OTPA) to find out high contributing vibration behavior of the body. As the result, high contributing vibration modes to the road noise were extracted by associating the high contributing PC mode with the vibration mode. Then, countermeasure was carried out to the high contributing vibration mode for the reduction of the road noise efficiently. And the road noise was confirmed to decrease well at the target frequency.

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In this study, we considered a contribution separation technique that separates road noise and wind noise contribution using only vehicle interior noise recorded at several positions. In the experiment, road noise and wind noise imitation signals were given to the vehicle model, and mixed interior noises were recorded at several positions. And then, independent component analysis (ICA) was applied to the recorded interior noise but the result indicated that each contribution could not be correctly obtained due to the low accuracy and the permutation problem, in which the relationship between the calculated and actual contributions was not retained with changes in frequency. Subsequently, we improved the accuracy by utilizing all recorded interior noise and developed original permutation solution using the correlation of calculated contributions of dominant independent component. By applying this technique, the ICA method with the permutation solution procedure correctly calculated the road and wind noise contributions.

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Noise generated from Shinkansen trains mainly consists of wheel/rail noise, bridge noise and aerodynamic noise. Generally rolling and bridge noises increase in proportional to the second to third power of the train speed, whereas the aerodynamic noise increases in proportional to the sixth to eighth power of the train speed. Then, the aerodynamic noise becomes dominant at above 300km/h. In the past studies, the main sources of the aerodynamic noise are the pantographs and bogies; the contribution of the aerodynamic bogie noise to the wayside noise is greater than that of pantographs. Therefore, wind tunnel tests and numerical simulations have been made to reduce the aerodynamic bogie noise. In this study, a new measurement method is proposed to identify the source of the aerodynamic bogie noise precisely in wind tunnel test; a part of the ground under a bogie is replaced by a porous plate through which the sound wave propagates but blocks off the air flow. A microphone array is installed under the porous plate toward the bogie. This measurement method made it possible to determine the sound source of the bogie in detail. It is found that traction motors and gear unit, which are located downstream in the bogie section, are dominant. This experimental method and results will lead to a better understanding of the aerodynamic bogie noise and the development of reduction techniques.

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Aerodynamic noise generated from the bogie section is one of main sources when high speed trains run above 300km/h. Therefore, it is important to reduce the aerodynamic noise appropriately. In this paper, the countermeasures to reduce the noise are investigated. In order to examine the effect of the countermeasures on the aerodynamic noise, a wind tunnel test was carried out by using two-dimensional microphone array, which were set under the bogie. Three countermeasures to control flow at the upstream of the bogie, i.e. single deflector, 3d deflector, and increasing the volume of underfloor, were developed. It is found that the noise is reduced properly by 3d deflector and increasing the volume of underfloor.

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In the past studies, when train runs at the speed about 300km/h, one of major aerodynamic noise sources below 100Hz is bogie cavities. In order to reduce the aerodynamic bogie noise efficiently, it is necessary to make a better understanding of the noise. In this paper, the mechanism of the aerodynamic bogie noise is investigated with a 1/70 scale train model using launching facility. Through the scale model experiment, it is found that the bogie cavity space is important to reduce the aerodynamic noise. So, we investigate the rounding or tapering edge of the bogie cavity. As the results, their edges of the bogie cavity are effective to reduce the aerodynamic noise.

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The fundamental sound absorbing characteristics of the perforated plate liner is given by some useful prediction formulas or by normal impedance tube measurements, however these approaches are not sufficient for its application to the aero-engine inlets because of the presence of grazing flow. In our previous report, a method of determining the acoustic impedance of a liner by multiple microphones installed in the flow duct is introduced. This method is useful for the parametric studies because the liner can be attached easily, while the flow field measurement is required and its impedance eduction process is rather complicated. In this report, a method of calculating acoustic impedance directly by the microphones installed inside the liner is introduced and examined.

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The purpose of this study is to predict flow noise in an air conditioning duct system. Therefore, in this report, the acoustic characteristics of basic duct components are evaluated by wind tunnel experiments for comparing the accuracy of numerical analysis. The experiment was performed by using an anechoic room which can supply low noise air, then wind velocity, pressure and noise were measured in duct test pieces. As a result, a typical Aiolos tone and acoustic resonance were observed for the duct components of square cylinder and split type. For the noise generated by perforated metal, there is a strong correlation between the wind velocity passing through the hole and noise. Therefore, the result shows that flow noise can be substantially formulated by wind velocity.

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In order to improve the precision of predicting the fluid noise generated from an air conditioning duct, the analysis domain in fluid acoustic linkage analysis was studied and mesh size as an appropriate condition were studied using a blank duct without a specimen. As a result of studying consistency with the experimental results, it was found necessary to consider unevenness of the flow ground, and to divide the CFD mesh into at least 1/20 of the target wavelength. Furthermore, comparing the experimental results with a prismatic and partition plate model using the selected conditions, we studied the reproducibility of fluid acoustic linkage analysis.

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In the acoustic wind tunnel for experiments of aerodynamic sounds, it is required to make the background noise of the measurement section even quieter. The unsteady structure of shear flow of the jet from the nozzle attached with fine tiny vortex generating adapters was studied by numerical flow analysis by the lattice Boltzmann method and the experiment confirmed the stability of the airflow and the quiet ability. It was found that the collector throat can be downsized as compared with the conventional one, and the measurement chamber background noise can be quieter than the conventional one by about 3 dB. In addition, it was confirmed by imaging by numerical flow analysis that the fine tiny vortex generation adapter induces a longitudinal vortex flow effective for quieting.

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The characteristics of the transparent wall is researched in pressurized conditions with theoretical and experimental methods. It is cleared the influences of the wall material of for the frequency characteristics for the transmittance. Transmittance is influenced very large with the size of the wall and pressure. Transmittance at low frequency is become low in small size and large pressure. But the wall characteristics, the thickness, density and Young modulus, influence not so large to the transmittance. The vibration mode of the wall influences very much to the transmittance. It is important to control vibration at low mode for the small transmittance.

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In order to investigate the interior noise of automobiles, a cabin model for wind tunnel experiments and a MEMS microphone array were developed. Also we attempted to measure wavenumber-frequency spectrum of pressure fluctuations in the turbulent boundary layer to decompose hydro and acoustic pressure. The transfer function of the exterior aerodynamic noise to interior noise can be measured by using a concrete box for the cabin model. The wavenumber frequency spectra were estimated by using the developed MEMS microph one array. It can be decomposed the hydro and acoustics pressure fluctuation in the turbulent boundary layer. This method is useful for understanding the noise transmission mechanism of interior noise caused by flow around vehicles.

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Self-excited pure tone noise rarely occurs from an expansion valve in an air conditioner system. In this report, the experiment of the self-excited sound is performed when air is flowed through the expansion valve instead of refrigerant to investigate the cause of occurrence of the self-excited sound. The pure tone noise whose frequency is over 1000 Hz occurs in the experiment. From the measurement of vibration of the valve, the cause of self-excited sound is not coupling phenomenon of valve vibration and sound in pipe. Furthermore, from the spectrum of the sound and the characteristics of frequency when flow velocity is changed, we conjecture that the self-excited sound is generated from the jet sound whose frequency is locked by resonance．

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This paper describes the analysis of the acoustic characteristics of an expansion type silencer with extended-tube based on the equivalent circuit. The purpose of this study is to clarify the verification of the analysis based on the equivalent circuit by combination of an expansion type silencer and extended-tube in the numerical experiment．It is possible to model the acoustic characteristics of the expansion type silencer by a parallel network system. We investigate the transmission loss of the expansion silencers with extended-tube. Although the results show that the calculated results based on the equivalent circuit indicate the same tendency, we have not yet identified all the paths where silencing effect appears.

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This paper presents a study on a rattle noise by comparison between experimental results and numerical analysis results as to a vibro-acoustic model by FEM. It was difficult to examine the phenomena of rattle noise from experimental results for influence of background noise at low frequency regions. Simulating a rattle noise, the vibration model is constructed with a contact state by putting two pieces of strip-formed sheets made of the plastic on top of one another. As an input waveform, random vibration and sweep vibration are used, displacement excitation method is applied on a node which is pinned support. As a result, the influence of contact could be confirmed from the vibration and acoustic time history response analysis results by FEM with contact and without contact. Also, the effectiveness of the vibration and acoustic model with the influence of rattle noise is examined through calculations employing a FEM model with contact and without contact in the power spectral results of the analytical and the experimental results, it can be seen that the analytical acoustic results indicate the phenomena of rattle noise at low frequency regions.

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As a method of water leakage investigation of a water supply pipe, first diagnosis is made by the magnitude of the vibration sound transmitted from the water leakage part to the water meter. Furthermore, the presence or absence of water leakage is judged by secondary diagnosis of the recorded vibration sound with auditory perception. Therefore, it is desirable to reduce the number of judgment tasks that rely on human auditory perception to improve efficiency. We extracted features of water leak sound, decrease the number of data by time series analysis and acoustic filtering technology based on frequency analysis, and developed an algorithm to efficiently diagnose the presence or absence of water leakage. The number of vibration sounds subject to auditory assessment could be reduced to less than half of the conventional method, and we were able to save labor.

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Cyclic repeatability is an important determinant of the reliability of a system that works by reciprocating motion. In this paper, we studied the influence of the time constant on the cyclic repeatability. First, we defined the cyclic repeatability by the variance of ensembles. Second, we showed the variance of ensembles increases with decreasing the time constant using a first-order lag system. Third, we developed a prototyped system that generates an impact sound of solenoid driven by a repeated DC voltage to verify our conclusion. We confirmed that the variance of solenoid current, armature velocity and impact force relate with the time constant or rise time of the system derived from a functional model.

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It is necessary to examine comfortable vibrations and swinging motions used in the development of a humanmachine interface. The author focused on the period fluctuations of rhythms produced by humans for their own enjoyment. The body rhythms occurring when walking comfortably along a sidewalk and when walking monotonously on a track were measured using a portable acceleration measurement system. Then, periods of the rhythms and fluctuations of the periods were obtained, and the power spectra of the period fluctuations were examined and compared. As a result, the power spectra of both cases showed a downward slope within a low-frequency range, and the spectra in case of walking comfortably were more similar to the spectra with property of 1/f, on the other hand, the spectra in case of walking monotonously were more similar to the spectra with property of white noise.

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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 Hz. Noise at frequencies below about 20 Hz is sometimes referred to as infrasound and this type of noise presents even greater difficulties in its measurement and assessment. The objective of our research is to suggest practical means of reducing the low frequency noise emanating from the opening of soundproof houses. This paper describes an experimental research on the alleviation of low frequency noise by the filtered-x LMS active noise control in a subscale model house.

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In this paper, we propose a new method to reduce noise globally based on wavefront synthesis. In the conventional method of multi-channel active noise control based on wavefront synthesis, the control sound is reproduced to correspond the shape of wavefront of the noise into synthesis area around the control point. However, in case there is something around the control point, it is difficult to reproduce the wavefront of the control sound into the area. In the proposed method, we detach synthesis area from control point so that the influence of the obstacle is ignored. The effectiveness of the proposed approach is verified by numerical simulation with BEM.

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Reduction in aerodynamic noise emitted from a pantograph is an important subject for environmental preservation and speed-up of Shinkansen trains. In this study, aerodynamic noise reduction by applying porous material to pantograph head support was investigated. For the purpose of installation strength improvement, porous material was embedded with flush mounting with necessity minimum area. As a result, it is clarified that the porous material can reduce aerodynamic noise emitted by pantograph head support.

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In the present paper the attention is focused on the effect of plasma actuator on aerodynamic sound radiated from two-dimensional airfoil. We measured the aerodynamic sound radiated from the airfoil with plasma actuator near the trailing edge of the airfoil. At the normal airfoil, discrete frequency noise clearly observed at small attack angle for Re=0.9×10⁵～1.2×10⁵ . The plasma actuator was effective to reduce the discrete frequency noise radiated from airfoil. This noise depended on the electrode length of plasma actuator and flow conditions. We have discussed the effective geometry and flow conditions to reduce the discrete frequency noise.

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An natural acoustic frequency of an one dimensional duct partitioned by a perforated plate was clarified to come down with decreasing aperture ratio experimentally and analytically. The analytical results due to the Transfer Matrix Method are in good agreement with the experimental results. In order to clarify the reason, the impedance of an orifice by Melling is compared with that by the present method (T.M.M). The both impedances are in good agreement with each other. As a result, it was clarified that the Transfer Matrix Method can be used in prediction of the natural acoustic frequency of the one dimensional duct with the perforated plate.

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This paper deals with the effect of the set position of a perforated plate on the acoustic natural frequency of an one dimensional sound field partitioned by the perforated plate. The acoustic experiments using the one dimensional duct partitioned by the perforated plate and the numerical analysis by the transfer matrix method were conducted. As a result, it was clarified that the effect of the set position of the perforated plate on the acoustic natural frequency is small when it is set at the node of the particle velocity mode. On the other hand, it becomes large when the perforated plate is set at the belly of the mode.

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In this Study, we have taken data about Teshima waste treatment project over thirteen years. In this paper, we put focus on Teshima waste treatment project economic and environmental by using LCA (Life Cycle Assessments) and LCC (Life Cycle Cost). Usually, LCA is a tool to measure the environmental load in the life cycle from production or construction to use, service, disposal or removal. In this study we focus on use and service. We found the environmental impact of intermediate treatment facility (melting facility) occupied the greatest load among the whole processes. Moreover, during the attempt to complete the project within the deadline decided by the prefecture, we can see the trend of environmental impact increase due to digging process and waste transportation process towards completion of removal. Comparing the Teshima waste treatment project with the general waste disposal facilities, we found that the load of the Teshima waste treatment project is extremely large both in terms of economic and environmental impact.

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It has been 14 years since the automobile recycling law enacted and functioning smoothly. Promotion and improvement of automobile recycling system are necessarily. However, studies on the utilization level analysis of End of Life Vehicle (ELV) that are qualified for producing recycle parts products are insufficient. In this paper, we evaluate the production ratio of reuse parts from a vehicle’s type by model year view and an engine displacement perspective. We analyze the commercialization proportion from actual commercialized reuse parts products by listing the qualified reuse parts products and excluding those from a damage condition ELV. As results, we find out that the production ratio become higher when the model year is newer and the engine displacement is larger. Furthermore, regarding the category of reuse parts, it is found that the production rates of exterior parts and driving parts are higher. This paper aims to promote the reuse parts products through this evaluation.

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It has been 14 years since the automobile recycling law enacted and functioning smoothly. Promotion and improvement of automobile recycling system are necessarily. Hence, business organizations are taking measures to conduct public relations campaigns of reuse parts products. However, studies on present selling situations that promotes the utilization of those products are insufficient. In this study, we investigate the selling situations from a reuse parts product dealer. And we evaluate the delivery ratio both from a vehicle’s type by model year view and an engine displacement perspective based on the analyses on the number of enquiry reuse parts products and actual product delivery proportion. This paper aims to promote the reuse parts products through this evaluation.

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JFE Engineering has continued to make various efforts from an early stage for PFI/DBO projects involving the joint management of facilities by the government and private businesses, and is engaged in operating waste to energy plants through long-term comprehensive commissioned projects. JFE Hyper Remote was developed to reduce plant life cycle cost and to support safe and stable operation. Connecting by the high speed optical fiber networks in various plants beginning with waste to energy plants constructed and operated by JFE Engineering and the Global Remote Center(GRC) at Yokohama headquarters, we provide comprehensive services by remote monitoring and operation support.

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We have developed the technique of numerical simulation which uses the reduced reaction mechanism to predict the combustion behavior in a waste incinerator. In this paper, we newly made the reduced reaction mechanism “N916” (34 species, 76 reactions) for NOx concentration prediction by benchmarking GRI-Mech3.0 (50 species, 326 reactions) which is the typical combustion reaction mechanism. In order to examine the precision of N916, we calculated temperature and NOx concentration distribution in two-dimensional diffusion flame by using N916 and GRI-Mech3.0. The results showed that temperature and NOx concentration distributions were similar and the rate of divergence of NOx concentration value on center axis in the flame was almost 10%. There is a possibility that N916 is able to be used as the substitution for GRI-Mech3.0 in numerical simulation.

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In late years, with progresses of Artificial Intelligence image processing technology, some human works in the field of various industries have been replaced with AI. AI systems supporting human works are expected in operation of waste incineration facilities in our business. As a result of start research and development, the possibility of AI supporting a human work to monitor flow of slag is obtained. The accuracy of that is to be improved in the next phase.

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The latest waste incineration facility MUSASHINO CLEAN CENTER was completed on March 31, 2017 and the management started. The facility has some urban features, based on the concept of Musashino City. The facility supplies power and heat simultaneously to surrounding public facilities, through high efficiency power generation and advanced exhaust gas treatment of dry process, even immediately after disaster. In addition, the appearance is harmonized with townscape and the sophisticated service for visitors is provided.

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Commercial wood pellets are upgraded by the pyrolysis treatment in a wide temperature range of 378-773 K that includes both the torrefaction and carbonization temperature conditions. The trade-off relationship between apparent density and higher heating value of pyrolyzed wood pellets (PWP) is confirmed, which implies the existence of optimum pyrolysis condition to produce PWP. The progression of pyrolysis is found to be identified by the mass yield of PWP. Noticing the color variation of PWP with the progression of pyrolysis, the relationship between the mass yield and CIELAB color parameters is examined. Two experimental correlations to estimate the mass yield are presented using the color coordinate, b∗ and the hue angle, h. From the comparison between predicted mass yields and experimental data, it is found that the experimental correlation using the hue angle can evaluate the mass yield with an accuracy of around ±10% in a wide range of mass yield between 0.2 and 1. It is concluded that the proposed experimental correlation is useful for the non-destructive method to inspect qualities of PWP.

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Kindai University developed Biocoke as one of the biomass solid fuels. Biocoke is produced from biomass carrying on photosynthesis through a process of adding load and heat. Biocoke has physical and mechanical characteristics such as high apparent density and high compressive strength at room temperature. In this study, it is discussed that bulk density of each material effects on the formation characteristics of Biocoke. We use Japanese cedar and green tea as the materials with different bulk density. During producing Biocoke from these materials, we measure the height of specimens. After deriving the height, we calculate the porosity of specimens. Also, after producing Biocoke, we measure the compressive strength. In conclusion, it was shown that the difference of bulk density and porosity had little influence on the compressive strength of Biocoke.

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As a diameter of Biocoke is large, the inside structure is different from the outer periphery structure due to heat and pressure distribution in a formation process. A previous study was indicated that compressive strength of Biocoke, which is more than φ20 mm, decrease as a diameter is large. In this study, we conducted combustion tests at 973K by using Biocoke which has different diameter. Results were found in the following. The mass loss rate was proportionalto surface area of Biocoke during flaming combustion. The flaming combustion time and char combustion time were proportional to (V/S)² respectively. These results are suggested that a combustion behavior of Biocoke which has various diameter (geometric scale) is able to be predict.

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Natural expansion of bamboo forests is a problem to solve for agricultural or mountain-base districts in Japan. Although thinned bamboos must be discarded properly, the cost of it represents a burden on local governments. Therefore, the effective usage of bamboos is desired for dealing with this issue. On the other hand, bamboo is one of the prospective biomass energy resources for its rapid growth nature and relatively high heat value. However, it frequently causes an equipment malfunction by clinker formation in a combustor. For the effective usage of bamboo, the clinker and ash formation behaviors are supposed to be elucidated. In the present study, we observed the combustion and ash formation behaviors of bamboos with a single chip combustor for confirming the difference from those of woods. Further we observed the clinker formation behavior with a small stoker type combustor under various air temperature and O₂ concentration. Subsequently, the ashes show various types of appearance and the amount of clinker decreased with air temperature and O₂ concentration.

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The objectives of this study were as follows. Production conditions of small diameter Bio-coke with dimensions suitable for commercial wood pellet fired household stoves shall be clarified. Effective application methods should be found by prototyping the concrete material using the combustion ash as a raw material and investigating its characteristics. As a result, the following findings were obtained. (1) Manufacturing conditions for small diameter Bio-coke of dimensions applicable to commercially available wood pellet burning household stoves have been found. (2) It was found that the strength of mortar using woody ash tends to be inferior to ordinary mortar and fly ash mortar in the range of the age of 28 days used in the test of this time.

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