Experiments and numerical analyzes were performed on a flow rate adjustment damper used in a duct air-conditioning system, which generates fluid noise when blowing air. In the experiment, an anechoic chamber capable of supplying low-noise air was used, and an airflow adjustment damper was installed in the duct of the test apparatus to measure the sound pressure level. Next, the numerical analysis was performed using the decoupled method of the fluid analysis and the acoustic analysis, and the vortex structure and acoustic characteristics of the flow field generated by installing the airflow adjustment damper were discussed. Furthermore, we compared the acoustic characteristics with experiments and numerical analysis, and evaluated the practicality of the noise prediction accuracy of the numerical analysis.

Understanding the vortex flow mechanism of cavity tones is desired to control tones in aeroacoustics field. With respect to cavity tones in deep cavity with acoustic resonances the mechanism of vortex flow has not been made clear enough. When the circulation of the flow around the upstream side edge of the cavity exceeds the predetermined value, the phenomenon that the vortex might flow out is the cause of the cavity tones. It would be the estimated mechanism that the particle velocity of the resonant sound wave influences on the limitation of circulation around the upstream edge for releasing a vortex from the edge. We have tried to simulate the real phenomenon by simple numerical calculation with this assumption mechanism. As a result of trial and error, it became possible to explain the phenomenon of cavity tones with resonance by some assumption mechanism.

With the on-going heightened issues on climate change, the Fuel Cell Vehicles (FCV) are attracting attention. A significant challenge in hydrogen automobiles is the storage method and safety, including the aerodynamic noise of high-pressure systems in pressure reducer systems. And, we have focused on a solenoid valve, which is a component of the Hydrogen Tank Solenoid (HTS) system. The solenoid valve is used for both filling the tank inside the FCV with hydrogen and supplying hydrogen from the tank to the fuel cell. In this study, we performed noise analysis of a solenoid valve, during filling to the tank and supplying from tank to solve the noise problem. In detail, the CFD analysis method was used to evaluate the flow characteristics inside the valve. In the result, it was found that the solenoid valve generates a larger sound pressure while filling hydrogen compared to the sound pressure while supplying hydrogen, and the main noise sources derived from the pilot valve and the excess flow valve area. In addition, the increase in turbulence intensity in the pilot valve area was supposed to be the largest cause of noise.

Low-frequency sound with a frequency of 100 Hz or lower is recognized as a form of noise pollution, and various studies have been reported in past. However, the effects on the human body of fluctuating low-frequency sounds, such as those generated by wind turbines, are still unclear, and the relationships between physical quantities are not yet clarified. In this study, we conducted two experiments on fluctuating low-frequency sound, created by amplitude modulation of carrier waves, using four woofers installed in the soundproof room. The first experiment measured the sensation threshold of low-frequency sound, and the second experiment measured the detection threshold while white noise exposed simultaneously. As a result, we could not find any tendency by differences of modulation degree or fluctuation cycle in the range of sound stimulus conditions measured in both studies.

Aerodynamic noise generated from Shinkansen train is one of the environmental problems. In order to develop the noise mitigation method effectively, microphone array and de-convolution method is widely used for source localization in a wind tunnel test. On the other hand, in many cases, evaluation point of Shinkansen noise 25 m away from the track along the viaduct section and different from that of the wind tunnel test. This paper describes an evaluation method of sound pressure level (SPL) at an arbitrary observation point based on the sound source localization obtained by de-convolution method. A point spread function (PSF) considering the effect of sound field, sound reflection and diffraction around the model stage, is calculated by numerical analysis (Boundary Element Method) and applied to the de-convolution method. The proposed method is evaluated by a speaker test by comparing with a result obtained by conventional PSF considering a free space. The results show that accuracy of source localization and estimated SPL at the observation point is improved by applying the proposed PSF.

Demands to measure sounds from a height for analyze three-dimensional distribution or radiation of sound are available. We thought it would be possible to measure the sound with a drone that is rapidly becoming widespread. The biggest obstacle to the idea is the sound of the drone itself. If the wave form of drone’s own sound can be estimated accurately, it is possible to obtain an object sound from the measured sound canceled by the estimated sound. We propose a method to estimate a sound wave form from a rotating signal of a rotter shaft. A sound of a single rotor of drone in a rotation had high mutual similarity. A rotor sound is estimated by expanding or shorten a wave form of pre-recording rotor sound. Good estimation results were obtained and the sound level of drone itself was reduced by about 15dB.

In this study, we considered a method to evaluate a hammering sound component using machine learning for construction inspection in drone noise condition. In the test, hammering inspection was performed using two tiles (defective and normal tiles) with or without drone noise. For carrying out automatic hammering sound evaluation, machine learning model was prepared using a lot of hammering sounds obtained at quiet condition. Then we applied the model to the hammering sound with drone noise to evaluate the tile conditions. However, the accuracy was insufficient due to the noise. For the improvement of the accuracy, we made machine learning model again using standardized SPL in each 1/3 octave band to reduce the noise influence. In addition, we also applied a noise reduction method using acoustic transfer function. As the result, the accuracy was improved so much and the automatic hammering sound inspection method under drone noise condition could be realized.

Parametric speakers can output beam-shape audible sound by using the non-linear interaction of ultrasonic waves. In recent years, a sound absorption coefficient measurement method using a parametric speaker has been proposed, and parametric speakers are increasingly being used in acoustic spaces with reflective. Many discrete analyses by using finite difference time domain method have been proposed as analysis methods for parametric speakers, but the methods have problem that the calculation load is heavy. In this research, we construct a steady-state response analysis method that can efficiently analyze the audible sound of parametric speakers. We propose a method that combines a nonlinear concentrated mass model and a perturbation method. Impedance boundaries are set at the edges of the acoustic space to accommodate reflective spaces. In this report, we create an axisymmetric two-dimensional model and confirm the validity of the proposed model by numerical calculation in the acoustic space without reflection at the boundaries.

Vibration characteristics of construction equipment cab are very important for the evaluation of ride quality evaluation. Due to the large mass of the construction equipment, operator’s effects on the vibration characteristics have not been studied much. In this paper, we investigated the effects of the operator and a weight equal to the operator by experiment and numerical simulation. It was found that the effect of the operator is different from that of the weight equal to the operator and the body fat percentage of operator also has effects on the vibration characteristic.

Operational TPA was developed to obtain contributions with small man-hour. In the method, all reference and response signals are necessary to be measured at exactly same timing by single measurement system. However, this occasionally requires large measurement system depending on the products and may decrease the applicability of the method. In this study, we propose a method for obtaining high contributing part (reference point) to the response point at the operational condition by OTPA using several measurement systems. In the proposed method, the measurement timing gap among measurement systems is estimated using the estimation error of OTPA between calculated and measured response signals. As a verification of the proposed method, we applied this procedure to a simple vehicle model and compared the obtained contribution with the contributions by OTPA using single measurement system. As the result, the contribution of the proposed method was verified to have an ability to obtain the correct contribution by several measurement systems.

As machines become more complex, it becomes more difficult for human beings to monitor the condition of the machine by only observing it from outside or listening to the operation sound. In order to prevent serious accidents, it is necessary that the machine informs the condition to human beings instantaneously, and that human beings respond appropriately. That is, the human-machine interface is important. For example, when human beings drive a car, visual, auditory, olfactory and tactile senses are used. For the visual sense, it is used for grasping the map information displayed on the car navigation system in addition to grasping the road and traffic conditions, so there is no margin for it. For the auditory sense, it is used for listening to music to relax in addition to grasping the road and vehicle conditions, so there is no margin for it. For the olfactory sense, it is used for grasping the vehicle condition by an unusual odor. For the tactile sense, it is used for grasping the road condition and vehicle motion. It is considered that there is a margin for it, since the sensory receptors for the tactile sense are widely distributed. Then, we have been proposed that vibration stimulus using a chair with a built-in vibration generator applying speaker technology are used to inform a driver about the risks. In this study, impressions on five designing vibrations for driving assistant system were confirmed by factor analysis.

This paper deals with the problem of reproducing different sounds for different areas in the same space. To solve this problem, it is necessary to find a filter that enables the broadband control in the time domain. This paper presents such a solution including following procedures. Firstly, calculate the transfer function from the sound sources to the control points at each target frequency using Fourier transformation. Secondly, find the frequency characteristics of the control filter for each sound source using acoustic contrast control (ACC) based on the transfer function. Then, find the impulse response of the control filter, which can also be seen as the coefficients of a FIR filter, by performing discrete inverse Fourier transformation. Finally, by passing the input signal of a sound source through its corresponding control filter, the sound space can be divided into an acoustic bright zone (area where the input sound can be heard) and a dark zone (area where the input sound can’t be heard). Simulations and experiments are conducted to verify this method, and the results show that the method is effective to deliver different time series signals to different areas. In addition, the reverberate noise that is contained in the control result is also discussed in this paper.

This paper presents a noise eliminating duct with a structure that controls the direction of sound reflection on a wall. Controlling the reflection direction can increase the number of reflections and reduce the reflected sound. The optimized shape of a noise eliminating duct was created through optimization method using shape expression method by Radial Basis Function Network and acoustic analysis by boundary element method. The simulation result of the sound pressure level distribution of radiated sound for optimized shape shows bias in the direction as designed. This result confirms the usefulness of the design methodology.

Reduction in aerodynamic noise emitted from a pantograph is an important subject for reducing environmental impact and speed-up of high-speed trains. In the previous study, aerodynamic noise reduction method by smoothing pantograph head cross section and applying porous material to pantograph head support were proposed. In this study, to develop an easier applicable technique, two methods of substituting porous material with plate with channels or perforated plate are investigated. From a wind tunnel test result, it is clarified that both methods can reduce aerodynamic noise significantly.

The present paper focuses on the effect of flow velocity on acoustic absorption performance of perforated plate. A perforated plate has singe orifice at the center of plate. We experimentally measured the flow velocity, acoustic pressure, and transfer function using the improved acoustic impedance tube. The normal incidence absorption coefficient was calculated from the measured transfer function using transfer function methods. As the flow velocity of air passing through the orifice increased, the peak level of the acoustic absorption coefficient decreased. Velocity measurements were performed around perforated plate by means of particle image velocimetry. The pair vortices were formed clearly at the downstream of the orifice due to incident sound of pure tone.

The efficient transportation by overhead cranes needs fast and accurate positioning, but residual vibration which prevents positioning accuracy generally tends to be induced by fast transportation. In previous paper, we proposed a control method which is based on the characteristic that the residual vibration is completely suppressed in a linear undamped system when excited by an external force which does not contain the natural frequency component of the system. To apply this characteristic to nonlinear damped systems, we defined the apparent external force which includes the influence of system nonlinearity and damping. Furthermore, a robustness improvement method against the estimation error of the natural frequency was proposed, and its effectiveness was verified by numerical simulations. In this paper, we verify the effectiveness of the robustness improvement method by experiments. The experimental apparatus consists of a trolley driven by a belt along a straight rail and a rigid rod coupled to the trolley at its upper end. Experiments demonstrate that this control method can suppress the residual vibration if there is no estimation error, and the robustness against the estimation error can be improved by the robustness improvement method.

For sounds with temporal energy fluctuations, the A-weighted sound pressure level may differ from the subjective impression when listening to the sound. It may be because humans use sounds with temporal energy fluctuations, such as voice and music, as a means of information transmission. In this presentation, we applied the method of analyzing the time-variability of acoustic signals using cyclostationary analysis to the Japanese cicada sounds and the cat's purr. We report the source mechanism estimation results focusing on the first-order and second-order cyclostationarity and the high-precision time-frequency analysis results.

Recently, in motor-driven products, the need for noise reduction has been increasing from the viewpoint of improving comfort. In particular, the high-frequency pure tone component generated by the motor, such as electromagnetic noise, is sometimes considered as harsh sound, and noise reduction is required from the viewpoint of improving sound quality. Therefore, in this study, to reduce the pure tone component from the motor, we made a prototype of an acoustic metamaterial in which 1/4 wavelength acoustic tubes were periodically arranged inside and evaluated noise reduction effect. In this paper, firstly, we describe the structure of the acoustic metamaterial prototype which can reduce 2600Hz peak frequency. Secondly, we evaluated the noise reduction effect of the acoustic metamaterial using an acoustic analysis software ACTRAN. As a result, the significant noise reduction effect was obtained at 2600Hz. Thirdly, we evaluated the noise reduction effect using a speaker test. As a result, the significant noise reduction effect was obtained at 2700Hz. finally, we compared the frequency characteristic of noise reduction effect between the acoustic analysis and the speaker test. As a result, the peak frequency of the noise reduction effect was a little different but the shape of the frequency characteristic around the peak frequency was almost the same. It means that it will be possible to estimate the noise reduction effect using the acoustic analysis by improving the analysis accuracy.

It is known that bogie cavity of Shinkansen trains is a major source of low-frequency aerodynamic noise. To investigate the generation mechanism of low-frequency noise, we conducted CFD analysis using 4-car trainset model . The result shows that meandering flow attributed to the bogie cavity generate low-frequency aerodynamic sound around 6 to 10 Hz, and the pressure fluctuation around 20Hz within the bogie cavity was observed. We found, furthermore, that it is possible to reduce low-frequency aerodynamic sound by changing the shape of the front and back corners of the bogie cavity to a gentle slope, or by reducing the volume of the bogie cavity.

Change in sound pressure level and A-weighted sound pressure level (Noise level) of radiated sound due to sound sources moving at the same constant velocity along a straight track is discussed in this paper. When sound sources move, frequency and amplitude modulation is observed in the radiated sound field. When the modulation is considered, calculated overall sound pressure level of the sources becomes larger than the calculated levels when it is not considered. The difference between maximum sound pressure level and the equivalent sound pressure level while the source is passing-by, with or without considering the modulation, increases monotonically with respect to source velocity. Source frequency characteristic depends on noise generation mechanism or structure of the sound source. Difference between calculated noise levels, with and without considering the modulation, increases as dominant source frequency decreases due to A-weighting below 1 kHz.

The introduction of solid biofuel to replace coal is expected to build a sustainable society. However, in order to increase the substitution rate, the development of bio-solid fuel having thermal decomposition characteristics similar to that of coal has become an issue. In this study, the effect of high-density molding on the thermal decomposition characteristics was investigated by using two types of biomass model compound, BM-Cedar and BM-C50L50. From the experimental results, it is found that the mass fraction of lignin equivalent is enhanced by high-density molding, and the char yield is correlated with mass fraction of lignin equivalent.

Currently, most of waste CFRP is landfilled and carbon fiber, which is a useful resource, has not been recovered. Pyrolysis methods and supercritical fluid dissolution methods have been studied as recycling methods, but have not yet been put into practical use. Separation of CFRP carbon fibers using microwaves has also been investigated, but the relationship between the carbon fiber direction and the microwave irradiation direction has not been clarified. Therefore, in this study, five types of CFRP with different laminated structures were heated with single-mode microwaves, and the relationship with the carbon fiber direction was investigated. The suitable irradiation condition for thermal decomposition of CFRP was evaluated based on the rate of residual resin. From the experimental results, it was found that the carbon fiber direction of CFRP, the laminated structure, and the electric and magnetic field strength of the standing microwave affect rate of residual resin. On the other hand, when irradiated with single mode microwave for 2 minutes or more, about 80% of the resin was removed from CFRP.

In Japan, illegal dumping of waste is a social problem, and proper disposal is required. In addition, there is a possibility of efficiency improvement in waste generation, collection and transportation and sorting processes. We will construct three systems to promote proper treatment of medical waste and improve the efficiency of collection work. 1. Traceability system by WCM, 2. AI automatic vehicle dispatch system, 3. Pick-up instruction system by one-touch button and weight sensor. The purpose is to conduct a demonstration experiment with the cooperation of clinics and collection and transportation companies in the I city area and propose a business model for social implementation. In addition, we will examine the possibility of expanding WCM to waste and recycled resources other than medical waste. For example, WCM can be expected to expand to the proof of origin of pruned branches in the FIT system. When using woody biomass as a fuel material, it is necessary to issue a certificate of origin. Introducing WCM with proof of origin will lead to improved work efficiency. In addition, WCM can be expected to be used for thinned wood and waste plastic.

Biocoke requires a large amount of energy for crushing when using powder for electric power applications. As a solution, torrefaction saves crushing energy and pulverizes it to expand the range of applications. This study discuss the effect of torrefied Biocoke (T-BIC) on combustion from combustion rate analysis. Since the fuel characteristics of T-BIC depende on the treatment conditions, combustion tests take at the furnace temperatures of 873K, 973K, and 1073K for those without torrefaction and for torrefied temperatures of 423K, 523K, and 623K, respectively. The result is derived as follows. with a Tb = 523K- T-BIC showed a pre-exponential factor of 0.00564 1/s and an activation energy of 11.73 kJ / mol., it can be estimated that dominated by the ignitability of low-temperature volatile components. At Tb = 623K-T-BIC, the frequency factor and activation energy is showed maximum values, the low-temperature volatile components volatilized, and the ignitability decreased due to the characteristics of the high-temperature volatile component. Tb = 723K-T-BIC found minimum values for both the frequency factor 0.00327 1/ s and the activation energy 11.60 kJ / mol. Especially, it is found char combustion became dominant and the ignitability improved due to the progress of carbonization.

In this paper, we examined the integration of power supply and demand and evaluated the CO2 reduction effect for a large-scale recycling center (hereinafter referred to as RC). Actual power measurement of each processing facility for the purpose of reducing carbon dioxide After evaluation and operation shift, it was shown that the CO2 reduction amount was 2590kg-CO2 / W in the week when surplus electricity was generated. In addition, the CO2 emission amount of RC was calculated by the annual coefficient method and the emission coefficient by time. It was shown that the error rate in November was 0.5% and the error rate in May was 18%, which differed depending on the season. Also, the CO2 reduction effect by utilizing RPF and trans heat container utilizing RC resources was shown. Evaluation was performed.

In this study, we investigate and propose the introduction of AI and IoT technologies for the upgrading of waste treatment systems through technology readiness assessment (TRA). First of all, in order to understand the examples of AI and IoT technologies currently used in waste treatment facilities, we organized information such as papers and constructed a database. Each technology was categorized by the process of waste incineration, and the contents of each were evaluated using TRL (Technology Readiness Level). As a result, it was found that most of the technologies used in MSW incineration plants had a high level of maturity, while many of the technologies used in the collection and transportation processes had only reached the level of demonstration tests and were not yet in widespread use. In addition, interviews with manufacturers revealed that even if manufacturers incorporate AI and IoT technologies, it is difficult for them to gain recognition for their efforts because local governments focus on results and efficiency.

In the parallel crisis of global warming and energy, renewable energy has become the primary target of all countries in the world. Taiwan, which uses thermal power as its main power supply, consumes a large amount of coal, whereas the development of renewable energy only accounts for 6% of the total power generation. Especially, we focused the biomass energy sustains less than 1% of the total power generation. Biocoke is a solid fuel that can be made from a variety of biomass resources. Due to its high density and high strength, Biocoke is expected to be a reliable source of alternative energy. In this study, Biocoke made by the residue of pineapple. Pineapple is one of Taiwan’s largest production fruits for an annual production volume of 500,000 ton. With an average moisture content in 80%, there will be more than 16,000 ton of waste per year. This study discussed the influence of parameters of initial moisture content, molding temperature, and apparent density on the fundamental characteristic of pineapple residue Biocoke.

Previous studies confirmed that bio-coke effect the carburizing degrees in iron casting by contacting bio-coke with the molten metal. However, the process and mechanism that explain the role of bio-coke in molten metal carbonization have not been clarified. Therefore, this study assumes that carbonized bio-coke came into contact with the molten metal during the casting process, then the molten metal absorbs the carbon from the contacted bio-coke.

Bio-coke samples were thermal-treated at the different carbonization levels. After that, the thermal-treated bio-coke were brought into contact with the molten metal to measure the degree of steel carbonization. The results revealed that the amount of carbon is increased when thermal-treated bio-coke were in touch with the molten metal. Moreover, the degrees of steel carbonization using thermal-treated bio-coke as an agent have been clarified.

This present research focuses on the improvement of the pre-carbonized solid biofuel, called Kindai Bio-coke. The bio-coke is currently applied in the large scale industry, such as the Cupola furnace of the steel industry, to reduce coal coke consumption. The properties involved with the permeability function need to be expressed in more detail to increase bio-coke consumption in the furnace. Two of the features, particle density and internal strength, of the Japanese cedar base bio-coke mixed with a single lignocellulose component (cellulose and alkali lignin) at 0, 2, 5, 8, 10, and 15 wt.% were studied. Results show that alkali lignin improves bio-coke properties significantly. The particle density of bio-coke with additional cellulose is increased in the range of 0 to 8 wt. % weight ratio and decrease afterward. Additional alkali lignin improves the bio-coke’s internal strength significantly at 10 and 15 wt. % ratio. In contrast, additional cellulose decreases the strength of bio-coke gradually.

Japan is facing carbon dioxide by 2050 at the 21st Conference of the Parties to the United Nations Framework Convention on Climate Change (COP21) held in 2015, as countries around the world are facing a situation where there is no time to deal with global warming. The goal is to reduce carbon emissions by 80%. In our laboratory, by developing a bio-solid fuel with higher density and higher hardness than non-carbonization conversion technology, we have brought coal coke closer to the properties required in a melting furnace and demonstrated a significant reduction in carbon dioxide. In order to develop a BIC that matches the dissolution characteristics, we will develop a method for observing the microscopic internal structure using ATR-FTIR. In this study, we process bio-coke to capture the changes in molecular structure that occur during molding of bio-coke and observe the internal structure by using spectroscopy. We report the results of experiments aimed at capturing the effects of pulverization methods and molding temperatures and changes in the internal structure of biocoke using quadratic differential analysis and PCA.

In recent years, in countries around the world, it has been made efforts to global warming. However, in Japan, the fossil fuel consumption ratio is high, so the introduction of renewable energy is indispensable for reducing carbon dioxide. Research is being conducted on fossil fuel alternative energy from petroleum, coal, etc., but in particular, the development of bio-coke conversion technology is desired as a renewable energy that can be substituted for coal coke. On the other hand, bio-combustion ash is generated when it is used. Although combustion ash is used as fertilizer for agricultural land, there is no effective use. In this study, in order to make effective use of the combustion ash, combustion ash was mixed as a raw material for bio-coke, and its molding and its functionality were examined. It was found that bio-coke with bio-combustion ash can be molded up to at least 50 wt.%. In particular, it was found that by adding about 10 wt.% of bio-combustion ash as a binder, the apparent density was increased by 4%, and the maximum hot compressive strength could be maximized while maintaining the maximum compressive strength.

Today, all over the world, we have serious environmental issue of the greenhouse gas emissions produced by fossil fuels. The greenhouse gas emission from the coal has especially been considered problematic, and EU member nations have decided not to use close to 60 % of the total coal fired power generation by 2030. In Japan, biomass is expected as a replacement for coal used as base power supply in electricity demand. In this situation, biocoke which is a solid biofuel produced from biomass is useful for transport because of its high-density. Bio-coke, however, needs crushing to feed as a co-firing fuel with coal in co-firing power generation. In this study, after producing biocokes, we calculated their particle density. We also measured biocoke compressive strength with a compression testing machine and crushing energy with a hammer mill. We investigated relationship between the particle density and the compressive strength. Furthermore, we considered relationship between the crushing energy and the compressive strength. In conclusion, we found that the particle density bears a direct relation to the compressive strength. Additionally, we suggested that the crushing energy is in inverse proportion to the compressive strength, especially Japanese cedar, and a factor that affects crushing energy is a particle size in raw materials rather than the compressive strength.

This paper describes about Ultra Light-weight Vehicle (ULV) which is a vehicle that can to operate with the smallest body size and the least energy consumption. From the recent development of automobiles society, there is a high demand for a small size and environmental-friendly mobility. In this paper, as a part of the ULV development strategy, we examined the model ULV-A that uses compressed air as an energy source. A rotary vane type air motor was used for the prime mover. The performance of the air motor was evaluated from the engine unit performance test and the running test on the chassis dynamo. Focusing on the air flow rate, the relationship between pressure and output was confirmed. In addition, in order to improve the short cruising range, which has been an issue in the past, the structure of the vehicle will be fundamentally reviewed and a new ULV will be built in pursuit of weight reduction.

Garbage collection in Japan is not contactless，and in 2020，a case of COVID-19 infection occurred among garbage collection workers．Therefore，contactless garbage collection is an urgent issue．In Europe，the U.S.，and China， contactless garbage collection has become widespread with arms and loaders，and we surveyed case studies．We also found that the robotics industry is also tending to enter the garbage collection market．In order to implement contactless garbage collection using Modular Compact Mobility (MCM)，we first developed a scenario and then applied it to a city to create a demonstration model．By using this model to propose contactless garbage collection to another city，we were able to extract communities with needs for contactless garbage collection in the form of proposals for demonstration fields.

It is known that char combustion duration is almost proportional to the product of the inverse square of the specific surface area and the fixed carbon content of the briquette. It is suggested that the proportional constant C_c can be correlated with the mass percentage of the ash content in the biomass raw materials. However, the individual influence of cellulose, hemicellulose and ash content on the char combustion durations, and thus on C_c, have not been clarified yet. In the present study, to investigate the effects of holocellulose content, cellulose (hemicellulose) content in holocellulose, and ash content in raw materials on C_c in detail, briquettes made of artificial raw materials adding cellulose, hemicellulose powder or cypress ash to cypress were burned in the hot air flow. It was found that char combustion duration for briquettes manufactured from artificially formulated raw materials is also proportional to the product of the inverse square of the specific surface area and the fixed carbon content of the briquette. It was seen that there was little dependence of holocellulose content and cellulose content in holocellulose on 1/C_c. It was confirmed that increasing the ash content decreased 1/C_c, and the dependence decreased as the ash content increased.

Most of the components that make up a wide variety of biomass in the world are cellulose, hemicellulose, and lignin. The ratio of these components affects the apparent density, mechanical strength, and combustion characteristics of Bio-coke. In present study, Bio-coke was formed from a mixed material of cellulose-rich cedar executives and lignin-rich cedar bark, and the effects of biomass components on the Bio-coke combustion characteristics were investigated. It was found that the flaming combustion rate increases as the amount of cellulose and hemicellulose in the Bio-coke increases, and increasing the amount of lignin increases the char combustion rate. The collapse of the sample shape increases the char combustion rate.

In order to evaluate the influence of temperature on the corrosion behavior, the molten salt corrosion tests were performed by the simulated ash salt environment at 758 and 783 K using NaCl-KCl-Na₂SO₄-K₂SO₄-CaSO₄ systems, and the mass loss was investigated from mass change before and after the corrosion test. At 758 K all specimens experience very little attack in the various S/Cl ratio molten salts. This results from no reaction between specimens and simulated ash salts. On the other hands, at 783 K all specimens show mass loss in the various S/Cl ratio molten salts. The corrosion rate is increased with S/Cl ratio.

We have developed a "closed loop VOC recovery system" that reduces VOC emissions to the atmosphere by treating VOC exhaust gas and then circulating and reusing it for the manufacturing process. We verified the impact on equipment performance and the customer’s product quality with the closed system equipment installed in the actual adhesive tape manufacturing process. As a result, it was demonstrated that the equipment performance target was achieved and that this system did not affect the quality of customer’s products. In this demonstration, in addition to confirming VOC recovery performance and energy saving performance, it was confirmed that the recovery solvent has almost the same properties as unused products, and that the customer’s manufacturing environment is stabilized by the closed system.

Volatile organic compounds (VOCs) and particulate matter (PM) emitted from factories in the painting and printing industries, and various exhaust gas regulations have been implemented. VOCs are the cause of photochemical oxidants and suspended PM such as PM2.5, which has become a global environmental problem. As one of the solution technologies, catalysis nonthermal plasma (NTP) techniques have been studied as VOCs control methods. In this study, in order to extend the application to the treatment of water-soluble VOCs, a wet-type catalysis plasma reactor is proposed. As an initial step to evaluate proposed technique, the simultaneous removal of nanoparticles and toluene or typical VOCs, are performed at relatively high gas flow rates of 10 L/min. As catalyst pellets, α-alumina spheres are filled in the NTP reactor, and a MnO₂ catalytic reactor is installed after the plasma reactor for ozone removal. Simultaneous removal of toluene and nanoparticles using dry and wet-type catalytic NTP reactors showed that the results used the wet-type reactor were superior in particle collection efficiency of 99%. As for the toluene removal efficiency, the dry-type was 91% and the wet-type was 73%, with the dry-type showing better results. However, the proposed wet-type catalysis NTP reactor could efficiently treat water-soluble VOCs, such as acetaldehyde and acetic acid.

Until now, the generation of air pollutants such as volatile organic compounds (VOCs) and particulate matter (PM) has become a social problem. Among them, VOCs such as toluene etc. are toxic compounds and released into the atmosphere. It is known that it is related with the production of photochemical oxidants and suspended particulate matter (SPM), and must be removed. In this study, VOC and PM were simultaneously removed with a wet packed-bed plasma reactor which was newly developed, and their removal performance was evaluated. As a result, at a water film flow rate of 100 mL/min, the particle collection efficiency of averaged 96% was achieved.

Currently, the reduction of greenhouse gas emissions is required, and since CO₂ accounts for most of the greenhouse gas emissions, it is essential to reduce CO₂ emissions. Among the various research and development activities on CO₂ emission reduction, CCU has been attracting attention. In this study, we focused on DRM using DBD plasma, and conducted DRM at ambient temperature and atmospheric pressure using spouted bed plasma reactor. In the experiments, DRM by DBD plasma was conducted and GC analysis of the outlet gas was performed. In the case of plasma generation, H₂ and CO were detected in the outlet gas, indicating that the DRM was feasible in spouted bed plasma reactor. However, no precipitates were observed in the reactor under the non-catalyst condition and almost no liquid products were observed in the liquid condenser. On the other hand, in the catalyst-filled condition, precipitates were observed on the surface of the catalyst and liquid products were obtained. In the case of the catalyst-filled DRM, liquid products as well as H₂ and CO were obtained, suggesting a synergistic effect of the catalyst and plasma.

An ammonia coaxial jet diffusion flame stabilized with hydrogen was analyzed. The calculations were performed using three schemes, and the best scheme was selected by comparing the calculation and experimental results. As a result, (1) The results obtained using the Creck-Mech well agreed with the experimental results of NO_x emission level and the flame structure, (2) When OH and H radicals were supplied by turbulent, a large amount of NO_x was induced. Concurrently, the mixing of NO and NH₃ and the reduction reaction were promoted, consequently reducing NO to N₂. Therefore, arranging the reduction zone where NO can sufficiently react with N, NH, and NH₂ is important in design.

High-pressure steam sterilization device, one of the sterilization devices for medical use, is a method which kills pathogenic microorganisms by filling the container with high-temperature and high-pressure steam. However, the amount of non-condensable gas in the container is regulated because the residual/leaked air into the steam leads to a decrease in performance. The indicator or other devices to measure this non-condensable gas are developed, but the behavior of non-condensable gas in the condensable gas is not clarified much yet because it is difficult to measure it. Therefore, in this study, we suggest a method to visualize and observe the non-condensable gas spatiotemporally in real time by using plasma emission lines that the wavelengths are different depending on the types of the gases. By this method, we clarified that the nitrogen gas in the steam is condensed near the cooling zone.

Hydrogen carriers are being considered because hydrogen is low energy density per volume, poor transport and storage efficiency, and high cost. Among them, the advantages of ammonia have high hydrogen content, carbon-free, and technology and infrastructure related to production, transportation and storage. So, a new high efficiency device for producing hydrogen from ammonia is required. In our laboratory, we have developed a high-purity hydrogen production device, plasma membrane reactor (PMR), which combines atmospheric pressure plasma and a hydrogen separation membrane. By combining catalytic reactor and PMR we have developed a system for producing high purity hydrogen from ammonia. However, there is a problem that hydrogen amount permeated from PMR is small. In this report, as a method for increasing the amount of hydrogen produced from PMR, Dielectric particles (zeolite) were filled in the plasma generating part. By filling the zeolite, plasma firing sate was stabilized and hydrogen separation flow rate was increased significantly. Experiments on hydrogen production from ammonia using a catalytic reactor and zeolite-filled PMR was conducted. When the supply ammonia flow rate was 240 L / h, hydrogen production of 304.2 L / h was achieved.

A simulation study was conducted to predict the concentration of nitrogen oxides (NO_x) generated in pulverized coal combustion. In this study, the chemical reaction analysis software ANSYS CHEMKIN 18.2 was used to construct a reactor network model and simulate the NO_x formation behavior during pulverized coal combustion based on the temperature distribution of the actual boiler, the initial composition of pulverized coal and feed gas, and the feed flow rate. In addition, the effect of Volatile N, which contributes significantly to the formation of NO was investigated. As a result, it was found that the NO_x production behavior could be well reproduced by devising the reactor model configuration, including the secondary air distribution method. It has also been confirmed that NO produced originated from Volatile N. Future work regarding this study involves further optimizing the reactor model and aims to improve the rate constants of elementary reactions in the NO reduction stage.

It is important to use combustible waste products as sustainable energy resources for reducing the usage of fossil fuels. One of the simplest ways to do that is the thermal recycling, in which waste products are burned in boilers to drive steam turbines and so on. To design boilers with high efficiencies and low environmental impacts, the residence time for char burnout in combustion zone should be appropriately estimated for each solid fuel. Sewage sludge accounts for 20% of industrial waste products discharged in Japan, although the large part of it is just incinerated without thermal recycling. Then, the objective in this study is to investigate fundamental combustion behaviors of sewage sludge as a solid fuel, in particular, to estimate char burnout in sewage sludge combustion, compared with other solid fuels like woody biomass. Thermo-gravimetrical analysis was combined with iso-thermal combustion experiments of dried sewage sludge samples. Effects of temperature and oxygen concentration were examined, and experimental results were analyzed based on reaction kinetics.

One of the CO₂-free hydrogen production methods is a system that produces hydrogen by the water electrolysis method using surplus electricity from renewable energy，but the hydrogen production efficiency itself is not high because the power consumption is very large．Therefore，the development of a device that can produce hydrogen from water with low power is desired．We have been developing a hydrogen production method that decomposes ammonia with atmospheric pressure plasma．We thought that atmospheric pressure plasma has a high electron temperature and can generate hydrogen by decomposing gaseous water (water vapor) with low power consumption．In this study，steam generated from distilled water and alkaline water (NH₃) was decomposed by electric discharge in a cylindrical plasma reactor，and the hydrogen generation behavior at that time was investigated.

Electric vehicles are becoming more and more popular around the world, but lithium-ion batteries, which are the mainstream batteries for automotive use, have several problems. In this paper, we investigate the charge-discharge behavior and rapidly - recharge characteristics of the nickel-hydrogen flow battery, which uses hydrogen as the anode active material. In this paper, we investigated the charging/discharging behavior and fast-charging characteristics of the battery. 5 consecutive cycles of charging/discharging tests showed that the discharge capacity decreased as the number of cycles increased. The weight of the battery decreased, and the drying of the electrolyte was found to be the cause. The decrease in discharge capacity could be prevented by supplying the battery with hydrogen that was moistened by bubbling. In the f charge test, the discharge capacity decreased as the C rate increased, from 364 mAh at 1 C charge to 199 mAh at 10 C rapidly recharge. Scanning electron microscopy (SEM) of the cathode surface before and after the test showed that the surface structure of the cathode after 10 C charging was changed compared to the cathode before charging.

A visualization experiment of the refrigerant R134a in the decompression expansion process was conducted to analyze using a high-speed camera. The phase transition from a liquid single-phase to a gas-liquid two-phase flow was observed when the refrigerant was decompressed during it passes through a thin flow path. The flow path size is W0.5× H0.5×L300 mm. The gas phase velocity and void fraction of the refrigerant were measured from the visualized image. and the local pressure in the flow path was estimated from the relationship between the superficial gas velocity and the absolute pressure. Then, the effect of the flow transition on the pressure drop was presented.

In order to reduce the amount of refrigerant charged in the refrigerator and to improve energy saving, heat exchangers are required to be compact and higher performance. The heat transfer between refrigerant and evaporator has been promoted by reducing the cross-sectional area of the refrigerant flow path. The purpose of this study is to promote heat transfer of an evaporator by changing the cross-sectional shape of the mini groove. The refrigerant R134a was visualized using a high-speed camera to observe the behavior of gas and liquid two phase flow under the recessed groove, U groove and V groove flow paths respectively. Moreover, the heat transfer coefficient was estimated to evaluate the correlation between flow and heat transfer characteristics. The result of this study indicates that the recessed groove has the best heat transfer coefficient.