The force applied to foundation from the anti-vibration device by the metal spring increases by resonance when the frequency of exciting force at starting passes through characteristic frequency. There is anti-vibration device with Visco Elastic Material to solve this problem. I studied the transmissibility when I used anti-vibration device with Visco Elastic Material for gas engine heat pump. A conclusion is that we can decrease half of the force applied to foundation at starting in the following only metal spring type.

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The impeller of dual cascades centrifugal fan consists of two cascades which are arranged in the span direction. The inner diameter, chord length and the number of blades are different between two cascades. In this experiment, the span of both cascades are varied with keeping the total span constant. Then the influences of the inlet/outlet area ratio of both cascades to the fan noise and the aerodynamics are researched. The fan noise level of the dual cascades cetrifugal fan is lower than that of the single cascade fan, and the aerodynamic performances of the former is almost the same to the latter at the maximum efficiency point.

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An experiment Method to analyze the transfer matrix of engine intake systems is proposed in this report. By using our 3-mirophones Method, the four terminal constants of each sub-system was obtained. And those of the whole system were superimposed by combination of sub-systems. Based on experimental results, these method have been proved to be sufficiently reasonable for analyzing acoustic characteristics of engine intake systems.

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The effects of geometric parameters and flow on the resonance flequency characteristics of Helmeholtz resonator type silencers have been investigated. It is shown that the end correction of a resonator is varied by the dimensionless frequency, the parameters on the shape of connector open-ends and connector itself, and the flow velocity. Consequently, the resonance frequency is shifted owing to the change of the effective length of a connector. In this case, the resonance energy at a silencer entrance is affected by the ratio of connector diameter to duct width as well as the flow velocity.

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The flow induced noise from simple expansion cavity type mufflers with pulsating flow was studied. Generation characteristics of the flow induced noise were compared between the cases with pulsating flow and steady flow. Main components of the flow induced noise from the muffler were found to be resonance noises of the cavity and tailpipe of the muffler with both steady and pulsating flow. The sound level of the tailpipe resonance was reduced with bellmouth at the entrance of the tailpipe. The sound level of the cavity resonance was reduced with bellmouth at the entrance of the cavity. The results showed that similar to the case with steady flow, the tailpipe resonance with pulsating flow was excited by the separation noise generated at the entrance of the tailpipe. Unlike the case with the steady flow, the cavity resonance was excited not only by the shear noise generated at the entrance of the cavity but also by the turbulence noise generated near the exit of the cavity.

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This paper proposes a new type grouping actuation method based on a combination of inertial force type actuator and moment type actuator. Moreover, a control system is build using the concerned actuation method and previously defined distributed parameter modal sensor. As an advantage of the modal control, a simple control method is used for vibration control of a high-rise frame structure. The aim of this research is to develop new type sensor, actuator and control method using a smart structure.

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In the active noise control, a transfer characteristics of an acoustic feedback path has a considerable influence on the stability of the control system. When an acoustic system has a feedback path, the control system often causes unstable behavior called howling. An approach to prevent the howling named directional control sound source (DCSS) is investigated and compared with an ordinary approach (howling canceller) in this paper. This DCSS is composed of two sound sources and a finite impulse response (FIR) filter. Active noise control using the filtered-x LMS algorithm is carried out in an L-formed duct model. It is shown that the DCSS approaches prevented the howling effectively through the experiment.

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The transient response of head/disk interface in a non-operating hard disk drive is investigated theoretically and by FE simulation, subjected to half-sine shock pulse in the axial directions. The equations of motion are driven by Hamilton principle. To get the solution, the assumed mode approximation is used and then the Galerkin method is applied. Numerical results are obtained using the Runge-Kutta method for a 3.5 hard disk/head system. The results are good agreement with FE simulation. It is found that the head slap is caused not by disk shock response, but by suspension dynamic behavior dominantly. Design parameter study of suspension is performed to find out the optimal value increasing the shock resistance of a disk drive.

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This paper describes reduction method of Jet-Fan noise using Active Noise Control (ANC) systems. The dominant frequency component of Jet-Fan noise is the blade passing frequency (BPF) of rotating fan blades. To reduce the BPF, we have used a multi channel ANC system using four error sensors and twelve speakers. Results show, (1) Coupling one error sensor and three speakers is effective. (2) The BPF component can be reduced by 9dB three-dimensionally at the optimal position of the error sensors.

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New control algorithm for reducing sound pressure level of fan noise is proposed. As the algorithm basically comes from learning control which is invented for controlling the repetitive motion of a robot, it is effective for reducing the periodic components of fan noise. The control system utilizing the algorithm contains only error microphones without reference signal, which means the computer program realizing the algorithm is much shorter than that for conventional control algorithms, filetered-X or filetered ε, for example. The control experiment was conducted to prove the high efficiency of the new control algorithm. The result of the control experiment proved the superiority of the learning control over the conventional algorithms.

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The low frequency noise radiated from an engine is one of the social problems for environmental noise. The performance, in terms of power attenuation, of sound absorption materials or barriers is relatively poor at low frequencies. Therefore, the authors propose a method employing an active noise control for minimizing the total acoustic power radiated from an engine, leading to an environmental noise reduction in the entire area around an engine. Suitable arrangement of sources and error-microphone are investigated by the basis of theoretical estimation. The power attenuation effects of an engine was examined by simulation and experiment.

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In this paper, shoes sounds at walking are investigated. Their sound may show individual walking characteristics. So we can recognize someone coming and one's physical or psychological condition by the time history pattern of their sound pressures. Their sounds are different by walking style, and there are two strong sound pressure waves at one step. The first one is a wave at heel touching down the ground and the second one is a wave at the front part of shoes getting down the ground. We investigate what part of the sound wave shows someone's feature. We don't understand the source of generating walking sound yet. Then we investigate the source by analysis of exciting response method.

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"Suikinkutsu" is a sound system to amplify water drop sound in a basin. At first, we studied on water drop sound and its resonance at the space in order to analyze suikinkutsu. Vibration of bubble generates water drop sound. Volume of bubble decides the frequency of water drop sound. Resonance at the space in the basin amplifies the specific frequency defined by the natural frequency of space in the basin. From results of their studies, we clarified the characteristics of suikinkutsu sound.

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This paper discrives the analysis and evaluation of sound from waterflows. The experimental waterflows containing the step are setup in the Anechoic Chamber and the sounds from the water step flow are recorded in DAT. Then the sounds are analysised by Sound Valuation System. The Sense experiments evaluated by healing examinations are put into practice and the propriety of Sound Valuation System is considered. Finally, the comfortablity of waterflows sounds is cleared and the analysis methods of them are established.

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In this paper, vibration signals are investigated. Vibration signal is a vibration we use with special purposes or intentions. Vibration signal can transmit information to person through the sense of touch. Vibrators of portable phones are one kind of examples. They tell us only arrival of the call. We can not discriminate who call us. If we are able to make various types of vibration signal, it can help the sense of sight and hearing. The purpose of this study is to research on human sensitivity by vibration frequency, vibration pattern and parts of body that receive signals, and to propose the most suitable vibration signal for information.

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Evaluation of human impression for acoustic environmental design at public space is very difficult and not generalized at this stage. This paper describes the trial experimental results and investigation of "Free Description of the Adjective" method for acoustic environmental design at public space. Evaluation results indicate that the acoustic environmental design influences the pleasant impression which subjects receive from the experiment space.

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This paper describes a laboratory study for investigating the contribution of sound quality on annoyance. To measure the annoyance, two kinds of subjective evaluation test were carried out, i.e., one for annoyance and the other for listening interference. Our findings were : (1) contribution of high frequency contents of road traffic noise on annoyance was significant, (2) the contribution of high frequency contents of road traffic noise due to its modification beyond 1kHz by increasing and decreasing its level was equivalent to 3dB (A) even when the levels of the noise were fixed to 70dB (A), and (3) multiple regression models for annoyance in terms of LAeq, roughness and sharpness were constructed and the trade off relationships between the sound quality parameters and LAeq were calculated. The value of trade off of one standard deviation in roughness and sharpness for annoyance were equivalent to 4.3 dB (A) and 0.9dB (A) respectively provided that one standard deviation in LAeq in the model was 6.0 dB (A).

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In this study, the heart beat fluctuation is proposed as an evaluation index of "comfortable swing". The power spectrum of the heart beat fluctuation is examined using the developed rocking chair drive unit. In a result, it is clarified that while the power spectrum of the heart beat fluctuation in experiencing the uncomfortable swinging becomes almost the relation of 1/f^<0.9>, the power spectrum of the heart beat fluctuation in experiencing the comfortable swing is tended to become white noise in 0.15&acd;0.4Hz frequency range and fall in frequency range over 0.4Hz. In addition. an active rocking chair. which realizes the "comfortable swing". is developed. It is driven by an electromagnetic cylinder. Then, it is confirmed by the heart beat fluctuation that the swing is evaluated with "comfortable swing".

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The authors have been developing a new type of noise barrier, ASE (Actively controlled acoustical Soft Edge) noise barrier. A prototype of ASE noise barrier with a length of 40m was erected along the test track of PWRI. Its noise reduction effects against a fixed noise source were 2-6 dB larger than that of the ordinary noise barrier, depending on the positions of the receiving points. Furthermore, its effect against a running heavy truck, at the speeds of 40 km/h and 80 km/h, was approximately 5 dB larger than that of the ordinary noise barrier in a peak value. It was also confirmed that the ASE had the same effect against the moving noise source, regardless of the speed, as against the fixed source.

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On a measurements of the noise generated by a wind turbine, wind induced noise upon a microphone placed on a ground board could sometimes be a trouble. For the measurement to be carried out without a hitch as well as to get possible information concerning countermeasure to the wind induced noise, near ground wind on the grassy field usually found around wind turbine site and its relation with the wind induced noise on the microphone had been carried out. It was found that while the wind speed for grown grass surface reduced compared to the cut grass or asphalt surfaces, wind induced noise levels were almost the same.

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It is known to be difficult to measure the acoustic material characteristics of low frequency sound and the data of the low frequency sound absorption cofficient is not sufficiently accumulated. In this study, we measured the low frequency sound absorption coffcient of the acoustic material with two-microphone method.

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It is well known that noise emitted from piping in process plant is deeply affected by vibration. However, it is very difficult that noise levels are estimated based on vibration levels at piping or cylindrical supports. This paper describes a experimental investigation of relation between radiated noise and vibration using method of EEMUA No.142,and study for influence on piping structure of generated noise inside piping using sound-structure interaction analysis which is the focus of major oil companies in recent years.

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A bubbling-fluidized bed furnace has been used conventionally to incinerate sewage sludge. In recent years, for sludge treatment, especially for incineration, measures are required to deal with changes and fluctuations in sludge properties due to : 1. High-calorie sewage sludge, 2. Centralized collection and treatment of sewage sludge, and 3. Mixed incineration of screenings. To cope with the above, the Fast Fluidized Bed Incinerator (circulating-fluidized bed incinerator), is expected to be applied effectively in a wide range for sewage sludge incineration. The operating conditions and facts obtained from an actual 90-ton sewage sludge/day plant using a fast-fluidized bed furnace are described in this report. A circulating-fluidized furnace system with a circulating loop equipped without a seal structure has been established. An self-standing structure has been developed to prevent vibrations, which has been an issue with conventional circulating-fluidized furnaces. Accordingly, moisture-load fluctuations (76&acd;83%) has been dealt with sufficiently. Moisture and calorie fluctuations due to mixed combustion of screenings have been absorbed sufficiently as well.

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In incineration of waste, persistent harmful chemicals such as dioxins and PCBs are sometimes unintentionally produced because of uncontrolled combustion. In order to minimize these chemicals, waste melting is now being used because its high temperature condition (about 1300℃) thoroughly decomposes these substances. The waste melting furnace requires a combustion control based on the condition of melting waste. However, it has been almost impossible to know the melting waste volume in a waste melting furnace because of disturbances due to high temperature flame and flying ash etc. We developed a melting waste height sensor, based on a laser-radar system. So that the melting waste volume has become easily determined and a good melting control was identified in a pyrolysis melting furnace.

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This paper reports the mixing treatment test of MSW with excrement sludge or waste plastics in 10t/day demonstration plant of the fluidized-bed gasifying melting system in order to confirm the applicability of various wastes. MSW and sludge were mixed at 80 : 20,and MSW and plastics were mixed at 70 : 30. It was confirmed that these mixtures were treated properly as MSW is treated. It was also confirmed that the pollution in the mixing treatment of MSW and sludge or plastics was prevented at such the level as the pollution of the treatment of the MSW only. Especially, in the treatment of MSW and plastics, which contains comparatively large amount of chlorine, the level of the dioxins concentration in exhaust gas and fly ash was low enough to clear the standards of the law.

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NKK-type high-temperature gasifying and direct-melting process have technology for the treatment which is not only high heat value solid waste, but also no heat value solid waste like incinerator ash. In this time in our pilot plant, we treated high heat value solid waste of waste plastic, refuse derived fuel, separated plastic from municipal solid waste. Gas component for waste plastic treatment is heat value of 1,610 kcal/Nm3,recovery rate of the heat quantity reached 70%. In case of the treatment of high heat value solid waste, tar is not so mach concluded In the gas, and sulfide or nitride component in the gas is nearly equal to the treatment of municipal solid waste. It is estimated that gas heat value for waste plastic treatment enable to increase to 2,500 kcal/Nm3 with more less air rate.

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The char which removed 70%&acd;95% of the chlorine by the thermal cracking of municipal waste at 400&acd;450℃ is burned in a fluidized bed having a superheater made from ordinary low cost tubing and electrical power can be generated with a 30% efficiency by recovering superheated steam (80ata, 500℃). At the same time, the cracked gas is burned with air in an ash melted of the vertical swirling type, in which ash can be melted continuously at 1300&acd;1500℃. The slag from the melted ash in a number of ways. These processes occur when there is more than 1500 kcal/kg of LHV of waste. This system is compacted with a low excess air ratio (1.2&acd;1.3), and pollutant emissions at the outlet of the furnace are reduced.

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As a means not to use the external fuel for a heating source of pyrolysis drum, TAKUMA has developed such system that a part of pyrolysis gas generated due to pyrolysis of waste was burnt in a dedicated chamber as a fuel, and the high temperature air was generated through the indirect heat exchange with the combustion gas shown above, using the high temperature air heater, and such high temperature air was used for pyrolysis drum. It is possible to restrict the concentration of HCI to a low level, and to prevent the corrosion due to high temperature by burning the pyrolysis gas independently and further by using the combustion gas as a heat source of high temperature air heater. Besides, the method was also confirmed to provide the stabilized pyrolysis performance equivalent to that of conventional pyrolysis drum heating method in which the external fuel was used.

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The operating experiences of the Yame Seibu Clean Center of a Pyrolysis Gasification and Melting Ash System are reported based on the operation during Dec 1999-Mar 2000. In the system of Yame Seibu Clean Center, the municipal waste pyrolyzed by the pyrolysis durm and the pyrolyzed gas and carbon are burnt in the high temperature combustion chamber. We confirmed the stable combustion at low air ratio around 1.2,while CO emissions were lower than 10ppm. We also confirmed dioxin concentration at the stack less than 0.1ng/Nm3-TEQ. The slag leaching performance was excellent and the release of 6 heavy metals such as Cd, Pb satisfied the soil environment regulations. Bulk reduction of the waste less than 1/112 was achieved by recycling slag and ferrous material, non ferrous material.

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A 4.6 ton/day pyrolysis gasification waste treatment pilot plant has been developed. This plant is characterized as generating clean fuel gas from the waste by applying thermal decomposition and gas-cracking processes, then the generated clean gas is combusted perfectly. Continuous generation and combustion of the sufficient clean fuel gas from the waste, extra low level emissions of dioxins and other harmful substances, were successfully verified.

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A 4.6 ton/day pyrolysis gasification waste treatment pilot plant has been developed. This plant is characterized as generating clean fuel gas from the waste by applying thermal decomposition and gas-cracking processes. Continuous generation of the sufficient clean fuel gas from the waste, extra low level emissions of dioxins and other harmful substances, and the energy recovery by the generation of electric power through the gas engine system were successfully verified.

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Mechanism of dioxins formation during combustion process in municipal solid wastes has been discussed. In this study, the lab-scale fluidized bed combustor, designed to simulate the combustion process in a municipal solid waste incinerator, was employed. The multiple regression analysis as a statistical approach has been carried out to determine the effects of the RDF components on dioxin emission. In the experiment, artificial RDFs were used instead of practical RDFs to keep experimental accuracy. The results show that the dioxins concentrations increase with the amount of Cl, Cu and volatile matter in the RDF.

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The combustion performance of carbonized waste was investigated to use as solid fuel. The influence of fuel ratio on combustion of the car was studied experimentally using drop tube furnace. The results were compared with that of coal. It was revealed that the char of MSW have the same performance as coal if both fuel ratio are same. Fuel ratio of char depends on the major components of MSW and pyrolysis temperature in the production (pyrolysis) process. We estimated fuel ratio of char. Thermal analysis data of typical components of MSW was used for the estimation. It was resulted that we could predict the combustion performance of the char from the condition of pyrolysis.

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Formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) was examined to investigate the influence of forms (organic or inorganic) and levels of chlorine on the PCDD/Fs formation during municipal solid waste incineration. We used a laboratory-scale fluidized bed reactor with a freeboard section heated by electric furnaces. Artificial solid wastes with organic (polyvinyl chloride, PVC) and inorganic (NaCl) sources of chlorine in different levels and copper (CuCl_2・2H_2O) were synthesized to simulate the composition of municipal solid waste. In these experiments, increased Cl content in waste rises CO concentration in flue gas and promotes the PCDD/Fs formation. The amount of PCDD/Fs formed can be predicted by the average CO concentration and Cl content in waste. It could not be said that there is a significant difference between the influences of PVC and NaCl on PCDD/Fs formation during combustion of the artificial solid waste.

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There were several cases in which ash chutes were choked up with bottom ash in a few months at a stoker type municipal refuse incineration plant. The formation mechanism of choking product is considered as follows : (1) The formation of weak cement and pozzolan components were promoted owing to intermittent operation of final burning stoker. (2) Weak cement components, etc absorbed water above the water surface of the ash cooling tank owing to an amount of intermittent fall of ash and fiber type hydrates were produced. So ash chutes were consequently choked up with solid products. Making cross section size of ash chutes expanded and water spray onto the inner surface of ash chutes were effective to protect the formation of choking product at ash chutes.

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Melting furnace is largely classified into two types : one is electric type and the other is fuel type. The fuel type is better applied for the middle or small sized incinerator without generating equipment, which we have tested at this time. We have enriched with oxygen the combustion air for the fuel type surface melting furnace, aiming to attain the reduction of the fuel necessary for combustion and the reduction of exhaust gas generation. As the result, we have confirmed that we could attain 6% reduction of the fuel gas at the time when the the concentration of oxygen is 23.2%. We have obtained this figure both by experiment at the testing furnace and by theoretical calculation, and have found that those two figures are almost same.

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Polychlorodibenzo-dioxins (PCDD) and polychlorodibenzofurans (PCDFs) called "Dioxins" are persistent and toxic pollutants. We have investigated the applications of dehalogenation reactions with sodium hydroxide in 1,3-dimethy1-2-imidazolidinone (DMI), high polar and aprotic solvent, to the soil polluted with PCDDs and PCDFs. Aqueous solvent A has as high extraction capability of PCDDs and PCDFs from soil as toluene. Extracted PCDDs and PCDFs, which were treated in NaOH/DMI reagent at 200℃ for 1hr, were destructed and were not detected in reagent.

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Lately, various technologies for melting ash are introduced in order to decrease the environmental loads from waste-increation facilities. The fly ash from the melting process contains valuable metals of high volatility such as Pb, Zn and Cd at high concentration. But effective technologies for recycling these metals have not been established. This paper describes the method of recovering heavy metalsselectively from molten fly ash using molecular recognition technology (MRT) system. As a part of this attempt, we have installed a pilot plant of 30kg/h capacity in our premises and conducted Pb recovery tests. The result shows that high-purity lead was recovered. This paper also discusses the mass balance and the estimates of the operating cost based on the pilot test results.

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Research and development of dismantling as a method of disposing composite waste such as household electrical appliances, in which the waste is not pulverized, but heated in an atmosphere with minimum oxygen in its original form to be melted and gasified for dismantling. This is method with a minimum burden on the global environmental featuring : (a) Reduction in energy required for waste disposal. (b) Recovery of metals with a high level of purity. (c) Disposal of thermal insulation CFC as well as coolant CFC without additional costs. This research is on a sophisticated recycling system of small-scale wastes, being conducted as one theme on commission from the Manufacturing Science and Technology Center and the IMS.

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In recent years, the development of the recycling technique for the waste plastics has become very important. For making waste plastics raw materials, the study of the waste plastics recycling process using the coke oven was examined. As a result, it was found that the waste plastics recycling process with coal in the coke oven is suitable to produce coke, tar, light oil and gas without deterioration of the coke strength.

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In order to separate polyvinyl chloride (PVC) from the plastics of Packaging Waste efficiently, NKK developed new sorting technology, air-table. This technology has many benefits such as, simplicity of the process, applicability for mass separation and no-need fro waster-water treatment. In this paper, the separation efficiency of PVC from film plastics, plastics of Packaging Waste using the technology is reported.

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Home appliance shredder waste was treated in a 4.6 ton/day pyrolysis gasification waste treatment pilot plant. Urethane from waste refrigerator and waste plastics can be recycled as clean fuel gas that has low heating value of 5.0 MJ/m^3 and chlorofluocarbon (CFC-12) can be disassembled to low molecular gas very well. Emission of harmful substances, such as dioxins, is extra low and it is proved that pyrolysis gasification process is effective in recycling of home appliance waste.

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Gasification melting system is necessary for recycling and volume reduction of solid waste. However, combustible gases filled in shredding or gasification melting process cause explosion accidents. The current countermeasures against the accidents are the removal of explosive waste by hands, therefore the automation and laborsaving of work are expected. Several types of detection systems for the explosive waste have been suggested, however the explosive waste, which gives a signal actively, is more effective for the reliable detection. We propose an explosive waste detection system with ID tag, and examine the availability by the modeled experiments and simulations. 1) As a result of experiments in the effect of correlation of tag and metal and of read angle, Mount-on-Metal type tags are available for consumer electronics. 2) As a result of simulations, long tag is indispensable to decrease the effect of read angle.

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Gasification melting system is necessary for recycling and volume reduction of solid waste. Many explosion accidents, however, are caused by combustible gases filled in shredding or gasification melting process from gas cylinder and spray-can mixed within bulky waste. In this experiments which were conducted for inhibition of ignition in these process, using a spark plug as the source of ignition and mixed fuel composed of CH_4,CO and H_2,N_2 or CO_2 as the inert gas was added to pre-heated mixed fuel-air flow. As a result, 1) according to the ignition limit calculated by Le Chatelier's formula, on condition that waste contents too less moisture or has high heat quantity, there is a possibility that explosion accidents, 2) effect of ignition inhibition is valued by tendency to formation of organic and inorganic radicals.

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