It is necessary to examine comfortable vibrations and swinging motions used in the development of a human-machine interface. The author focused on the period fluctuations of rhythms produced by humans for their own enjoyment. The rhythms occurring when walking comfortably, hopping on a pogo stick, bouncing on an exercise ball, swinging on a swing, and dribbling a basketball were measured using a portable acceleration measurement system or a sound recording system. Then, periods of the rhythms were obtained, and the power spectra were examined. As a result, the power spectra showed a downward slope within a low-frequency range; that is, they are similar to the property of 1/f. In this study, the results of the frequency analysis were examined and compared. It was clarified that these power spectra have about the same magnitude, the periods are about the same, and the period fluctuations are not very large.

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In this research, the masking performance and the mental influence of five representative maskers are compared. Sound masking is an effective method to provide speech privacy and sound insulation in the environment where the structural sound insulation solutions, such as building a inner wall or a private room, are difficult to be carried out. In the preceding studies of sound masking, various maskers have been proposed. However, there is few research which comprehensively compares these various maskers. Therefore, this research aims to compare and investigate these maskers. As the first stage, this report introduces the generating principle and method of the maskers, and investigate the features of the maskers by frequency property analysis. Moreover, a trial to evaluate the sound masking performance by using the correlation coefficients of the time domain signals is conducted.

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In this research, we evaluate about masking effect on representative types of maskers such a noise type and a voice-compounded type. Each masker's features, and their applicable situations are examined in this paper. In the preceding studies of sound masking, various maskers have been proposed. For example, meaningless steady noise like spectrum limited pink noise, meaningless unsteady noise like environment noise has been proposed. However, few researches compare these masking effects. Therefore, this research aims to compare and investigate these maskers. This report examines masking effect by recognition rate while word pronouncing voice is masked.

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A new light sound insulation structure which is constructed with pressurized light inflated membrane bound by hard wire nets (Membrane Sound Insulator: MSI) was proposed and proved to have high sound insulation performance especially in low and middle frequency region according to its high rigidity in the previous papers. Moreover the sound insulation performance of MSI can be tuned by its air pressure. In this paper, in order to develop the structure of practical use, some composite structure which has double light weight walls with MSI between them were manufactured and tested. As the results, MSI was proved to increase the sound insulation performance of double wall in the middle frequency region in which normal double wall with sound absorbing material between them had poor sound insulation performance. Moreover, a simulation model predicting the sound transmission loss of MSI was developed and proved to be useful for studying the configuration of MSI qualitatively.

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The backward-curved centrifugal fan with rectangular casing is used to the air conditioners and the air cleaners that is required the compact and flexible design. We have pointed out that the performance of the fan is better than the fan with scroll casing at the large flow rate. But the noise characteristics of this type fan are not cleared yet. It is investigated the noise characteristics in relating to the interaction between the impeller and the rectangular casing by experiments and numerical simulation. The acoustic transparent wall is used to find out the noise source in the experiments. The turbulent noise is consists from the three frequency ranges that have the different noise sources. The low frequency range noise is generated from the impeller, the middle frequency range noise is generated from the casing wall and the high frequency range noise is generated from the shroud. One of the side walls is the most important to the high frequency noise. The secondary flow near the shroud causes the large turbulence and generates the high frequency and large turbulent noise. We proposed the obstacle setting to reduce the noise level.

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Aerodynamic noise generated from a high-speed train is a major environmental problem and its accurate estimation is essential for the efficient developments of the noise reduction technique. For the study of the aerodynamic noise, wind tunnel test with microphone array is useful to recognize noise sources easily. On the other hand, quantitative estimation will be also important for the further study. In order to evaluate the aerodynamic noise accurately, influence of the sound reflection due to the ground plate should be eliminated. In this study, we propose a method to correct a result of the microphone array measured with a sound reflection. First, acoustic interference caused by an image source was modeled suitably. Second, the reflection model was adapted to the beam forming analysis and the directive pattern, that is SPL distribution, was calculated. Finally, on the basis of the integrated SPL distribution, the correction coefficient was obtained. The method was also evaluated in the speaker test. It was shown that the correction level become large below approximately 2kHz and the source location near the ground, although the level in the higher frequency or higher source position are relatively small less than 1dB. It was also found that the integration area has an influence on the correction level especially in setting a threshold value.

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Due to limitations of the performance of computers, a prediction of structure-borne sound remains difficult for large-scale problems. Herein a prediction method for low-frequency structure-borne sound transmissions on concrete structures using the finite-difference time-domain scheme is proposed. The target structure is modeled as a composition of multiple plate and beam elements to reduce the dimensions of the vibration field compared to the three-dimensional discretization scheme. The scheme contributes to reduction of the calculation time and amount of required memory. To validate the proposed method, the vibration characteristics on a building structure obtained by the proposed method are compared to the measurement results. Comparison of the measured and simulated results suggests that the proposed method can be used to simulate real-scale structures.

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The paper describes acoustic characteristics by means of numerical analysis and measurement for the structures of absorptive material with elastic plate. Numerical analysis is carried out by finite difference time domain (FDTD) method. The update equations for the FDTD simulations in the sound filed with absorptive material and elastic plate modeled by the isotropy material are coupled at the boundary of both the mediums. We examine whether stiffness change of the elastic plate affects the transmission loss numerically and experimentally. It is found that acoustic characteristics of the absorptive material with elastic plate change depending upon the stiffness of the plate.

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We have proposed a concentrated mass model to perform a two-dimensional acoustic analysis. This model consists of masses, connecting springs, connecting dampers and based support dampers. In our previous report, we proposed a concentrated mass model for a coupled system which consists of acoustic space and a membrane and verified the validity of the model. However, the result of eigenvalue analysis by this model includes some modes which are physically inappropriate, such as spurious modes or zero frequencies. In this paper, a spurious mode removal model for a coupled system is proposed. The result of eigenvalue analysis agrees with modes calculated by FEM model and doesn't contain those inappropriate modes. Furthermore, the degree of freedom of this model can be reduced keeping its matrix symmetrical and its calculation time is faster than FEM's which has asymmetrical matrices. Therefore, it is concluded that the proposed model is valid for the coupled analysis of acoustic and vibration.

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In order to simulate interior wind noise of a vehicle, a coupling analysis of aerodynamic, structural vibration and acoustic were conducted. The prediction accuracy of noise was verified to compare with that of wind tunnel experiments. The predicted results are in good agreement with the measurement of wind tunnel experiments. It was confirmed that it is possible to predict the interior noise of up to 4 kHz. We also attempted to estimate contributions of each part to interior noise. As a result, it found that the sound insulation effect of the trim of the door portion and the roof is very large. Since trim reduced high-frequency noise, the noise contribution of windows became relatively large at high frequency region. On the other hand, the contribution of windows is small at low frequency region. It means when trims are removed, the contribution of doors become large.

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This paper describes a new method of designing low noise wing using Non-compact Green function represented by Mathieu function. The author stands for the theory of vortex sound for predicting wing noise from low Mach number flow, where the Green function represents the acoustical boundary condition. 'Compact Green function' has been developed for predicting the wing noise, whose usability is confined within low frequency range. On the contrary the new Non- compact Green function is feasible on high frequency range, since the function satisfies the Helmholtz equation in place of the Laplace equation. Mathieu function is introduced to represents the boundary condition of wing-like flat cylindrical body. Boundary condition of porous surface is considered to compose the Green function. Two cases are presented for designing method of low flow noise body, firstly a circular cylinder and secondly the slender 2-D wing. This paper presents designing examples of low-noise wing with porous surface.

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It is well known that major aeroacoustic sources remaining for Shinkansen are pantographs, bogies and gaps between cars. At the same time, these sound sources might include low-frequency noise, which is difficult to insulate with noise barrier. In this paper, an experimental facility that can launch a train model at high velocities is used to investigate sources of the low-frequency aeroacoustic sound. The comparative study of flat, bogie cavities and gaps between cars using 1/33.1 scale train model shows that bogie cavities generate low-frequency aeroacoustic sound in the range of 10 to 60 Hz, and side covers equipped with series E5 effectively reduce that sound.

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One of the problems with the aerodynamic sound, noise reduction along a railway line is very important for further speed-up of a high-speed train. In particular, the aerodynamic sound from a pantograph is one of the main noise sources. As one method for the aerodynamic sound reduction, this study apply to the cylinder with the step rings by a pantograph arm was proposed. Experimental investigation is carried out to clarify the aerodynamic sound and flow field by combination cylinders with the step rings and compared with those of straight cylinder.

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Reduction of aerodynamic noise emitted from a pantograph head is an important subject for environmental preservation and speed-up of Shinkansen trains. In the present study, control of flow around pantograph head using steady suction near the separation point was studied. The results of wind tunnel test show that the steady suction method can reduce the peak level of narrow-band noise known as the Aeolian tone. The peak level reduction depends on the suction flow rate rather than cross-sectional averaged suction flow speed. However, broad-band noise increases as the suction flow rate increases.

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A low-noise acoustic wind tunnels are usually used for the sake of clarification and reduction of aerodynamic noise. However, some cases of aerodynamic noise which are difficult to analyze enough by the experiment with only using acoustic wind tunnels have still remained without the best noise control. Three cases of self excited aerodynamic tone with acoustic resonance are introduced and consider reasons why it was difficult to measure and to analyze. Three cases are "air flow around a semi-cylindrical cavity", "air flow passing a inlet portion of compact compressor with ring-chamber", and "water jet from a nozzle connected to pipe wall in the water". The dominant reasons might be that unsteady flow pattern did not make clear by an acoustic wind tunnel and that acoustic resonance mode was more complexity to understand by only simple experiment.

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Malaysia's National Biomass Strategy 2020 has projected higher utilization of biomass, especially in palm oil plantation residues, to fulfil the national renewable energy target for converting biomass to energy. The bio-coke, a new solid fuel technology developed by Ida et al., is made from biomass, which has undergone constant heating and constant pressurizing to solidify the biomass. It is as an alternative fuel for coal coke, thus offers Malaysia a way to meet its renewable energy target and reduce emissions of greenhouse gases. However, bio-coke has lower carbon content compared to coal coke. Based on previous studies, the mixture of biomass with bio-char in the bio-coke materials improved the compressive strength under high temperature environment and improved the energy density of bio-coke. Bio-char is added in before the molding process of bio-coke and the end product is called bio-char-coke. In this study, the physical and mechanical characteristics of bio-char-coke from the mixture of oil palm EFB and coffee char is investigated. The results showed that the bio-char-coke produced tend to collapse when the coffee char content ratio was above 40wt% for lwt% initial moisture content and above 50wt% for 3wt%, 5wt%, 7wt% and 10wt% initial moisture content. This because of two reasons: 1) Lack in lignocellulosic components due to decrease in palm fiber content ratio; 2) Heat transfer between each particle became lower because more spaces were developed between each particle whenever coffee char content ratio is increased. Decrease in the lignocellulosic components also lowers the apparent density of bio-char-coke. Furthermore, the maximum compressive strength of bio-char-coke under room temperature environment is decreased when the coffee char content ratio is increased.

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Currently, our society depends upon a variety of energy resources such as oil, coal, and nuclear power. However, various problems arising anticipate the development of a new energy resource. From an environmentally friendly point of view, the reduction of carbon dioxide emissions that cause global warming and fossil fuel resource depletion are big problems and the Bio-coke, as a new self-sufficient energy in Japan, is being considered a solution. This study was carried out for the purpose of investigating the production characteristics of Bio-coke made from EFB fiber as a substitute fuel for coal coke.

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The oil separation system plays an important role in improving the quality of oily metal cutting chip as recycled materials disposed from metalworking factories. In this paper, a practical circulation-type superheated steam degreasing system, which is applied to oily metal cutting chip disposed from a metalworking factory, is evaluated. In order to show the advantages of a circulation-type superheated steam degreasing system, circulation-type and once-through type systems of superheated steam are experimentally examined. The evaluation parameters of the degreasing system chosen here are the energy consumption of the system and the degreasing performance. As a result, a circulation-type degreasing system conserves more energy consumption and removes more oil from waste material than the once-through type system. Therefore, a circulation-type superheated steam waste degreasing system that can process oily metal cutting chip provides a promising energy-saving waste metal recycle system.

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As the part of the research on functional addition of our sheet for applying paper prevention, the extension of the sign display function (visibility) was examined. The applying paper prevention sheet stopped illegal applying papers, and it contributed to the maintenance of the landscape. This sheet was developed as functional sheet (the sign sheet) with the information notice function. The material of our sheet was mainly the generality plastic, and the use endurance years in outdoor was a long term. However, it was required that the visibility of the information notice was retained, when information was shown at this sing sheet for the period equal to the use endurance years of an applying paper prevention sheet. As a notice method of information, the weather resistance of the outdoor use was considered, and it was appropriate to carry out the direct printing to an applying paper prevention sheet. It is optimum to carry out the ink jet printing which was correspondent to not uniform large scale printing but multi-itemed little scale printing. In this paper, the authors report research result following; weather resistance (ultraviolet ray-proof and rainfall-proof) or physical strength (antifriction, peeling-proof, skid-proof capacity) of printing visibility in the outdoor use of the sign sheet of ink jet printing for our applying paper prevention sheet. In addition, the application for the floor material is also reported, because the progressive experience of skid-proof capacity floor material was examined.

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Effective utilization of waste bio-oil such as fried oil is important for development of low emission engine. Grease trap oil collected from private sewerage system is one of the waste bio-oil and is so dirty and high viscosity that direct applying to the engine is difficult. In this work, however, properties of diesel combustion using mixture of heavy oil and grease trap oil (GTO) was discussed although simply filtration of GTO was carried out. Moreover, environmental burden applying mixture of heavy oil and GTO to commercial diesel generation was investigated. Fuel supply of the mixture differed only slightly with variation of GTO composition. In case of relatively high electric load, the fuel supply decreased when the composition of GTO was more than 30 %. It is thought that the viscosity influences the characteristics of fuel injection. NOx and SO_2 emission decreased with increase in the composition of GTO. On the contrary, concentration of CO in exhaust gas also decrease. The properties of NOx emission give an indication of reduction in temperature with increase in the composition of GTO but that of CO emission shows improvement of combustion state. On the other hand, the properties of SO_2 emission were lower than estimation values calculated from sulfur contents of these fuels.

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This paper describes about development of safety system for accidents in facilities. Accidents occur at frequency in waste management and recycling facilities taking an important role in construction of the recycling society. It is cause of waste diversification with the development of the recent industry and various services. So the citizen cannot cooperate with the increase in processing the construction of facilities. For improving these problems, safety system for accidents is demanded. We constructed accidents and troubles, "hiyari-hatto" data base (ATHDB-all) for waste and recycling facilities. This can stock accidents information that occurred at waste and recycling facilities and apply system for accident using typology method we developed. Furthermore, the safety education contents using 3D animation and information collecting system were developed and were introduced to the recycling company.

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The incineration plant with the Vertical Combustors of 27 tons/24 hours x 2 lines was completed in April, 2015. The performance test conducted in March prior to the commissioning achieved excellent performance with meeting the requirement of treatment capacity, and it was found that CO concentration was 1 ppm on average, NOx concentration was less than 50 ppm, both concentrations of HCl and SOx were one digit ppm, and unburned carbon of the incineration ash was almost zero. Such low figures were kept recorded also during the subsequent normal operation. The concentrations of Dioxins found in flue gas, bottom ash and fly ash were all much lowered than the standard regulation values. Although it is said that the maintaining stable operation of small-sized incinerators are difficult, the stable performance of the Vertical Combustors was achieved and confirmed.

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Dry-type baghouses are generally used to remove HCl and SOx generated through waste incineration by continuous spraying of slaked lime into flue gas cooled down to the temperature of less than 200 deg C. Due to its limitation of removal efficiency, however, wet-type treatment method is also introduced wherein those facilities under stringent emission regulations. Plantec Inc. have developed the Turbo Chemical Baghouse (high efficiency dry-type flue gas cleaning system) which forms thick chemical reaction layers of slaked lime on the filter cloths and achieves high removal rate equivalent to wet-type treatment method. It has been delivered in a number of incineration plants. In this study, the removal performance of the Turbo Chemical Baghouse was tested in the existing incineration facility by using a newly-installed laser-type HCl analyzer at the inlet of the baghouse in addition to the existing HCl and SOx analyzers located at the outlet of the same. The result showed that instantaneous values of both HCl and SOx were stably low level of less than 10 ppm at the outlet of the baghouse, and the HCl concentration at the outlet did not increase even when the incoming HCl concentration at the inlet was higher than 900 ppm in its peak.

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For global warming measures in the waste sector, high efficiency of waste power generation has been strongly demanded. Low NOx combustion technology is one of the measures. This time, we have advanced the EGR (Exhaust Gas Recirculation) technology and SNCR (Selective Non-Catalytic Reduction) technology, and introduced into the MSW (Municipal Solid Waste) incineration plant. With a combination of EGR and SNCR, it was possible to reduce the NOx to 30ppm (0_2=12%,dry) or less while suppressing the leakage of ammonia concentration 5ppm or less. As a result, by lowering the operating temperature of the De-NOx reactor and reducing the amount of steam used in the exhaust gas reheater, we confirmed the power generation amount increase.

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The Vertical Combustor is capable of stable incineration of various types of waste through waste pyrolysis with using minimum required amount of primary combustion air. Medical waste is normally segregated and stored in separate containers as per waste types at the source and is transported to the treatment facility. Medical waste packed in containers is directly fed into incinerators without any pretreatment such as mixing and shredding. Therefore, characteristics of waste to be combusted are fluctuated during continuous feeding of packed medical waste. The Vertical Combustor is capable of stable incineration of even such characteristically fluctuated waste without using supporting fuel. It has been widely introduced in medical waste treatment facilities. Furthermore, some of the plants using the Vertical Combustor are generating power through incineration of medical waste. It can be stated that the Vertical Combustor is not only addressing medical waste, but also contributing to effective utilization of energy in human society.

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Factors which forms a flow field in an electrostatic precipitator (ESP) is a shape of ESP, a gas flow velocity and an ionic wind. Ionic wind is a flow that occurs ions generated by corona discharge collide with air molecules. About the influence on the particles of the ion wind, it is not clarified enough. It is important for the clarification of a particle collecting process, and improvement in particle collecting efficiency to clarify the interaction in ESP including an ion wind. The new hole-type ESP was developed to minimize re-entrainment. In this study, it analyzed the particle behavior of hole-type ESP by using PIV (particle image velocimetry) analysis. This paper reports a PIV analysis result about an ion wind and the particle movement velocity.

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Carbon dioxide (CO_2) is one of the main substances linked to greenhouse effect, and its emission should be reduced. In this study, a CO_2 reduction treatment using an adsorbent and a nonthermal plasma flow is investigated. This treatment comprises a physical adsorption process and nitrogen (N_2) plasma reduction process. In the physical adsorption process, CO_2 is adsorbed by the adsorbent. In the N_2 plasma reduction process, the adsorbed CO_2 is reduced to CO by a nonthermal plasma flow that is generated by a plasma reactor with a circulating N_2 plasma flow. The generated CO can be reused as a fuel. We estimate this experiment results by calculating conversion efficiency of CO_2 to CO. In the N_2 plasma reduction process, the CO concentration reaches approximately 4.8% in maximum, and highest conversion energy efficiency of 11% is obtained.

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This paper describes NO_X reduction for a diesel engine using exhaust gas component recirculation (EGCR). EGCR is the aftertreatment technology for NO_X reduction by intake of NO_X extracted from exhaust gas to diesel engine. In this experiment, NO_X aftertreatment system equipped with heat exchanger and absorbent by using EGCR in the small diesel engine generator is investigated. EGCR system consists of absorption process and desorption process. These processes are conducted for 60 min each a cycle, and 5 cycles of experiments are investigated. The NO_X reduction efficiency of 36.9% is in the one cycle obtained. The numerical simulation of NO_X reduction using EGCR for the marine engine practically used in ships is also carried out.

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To remove nitric oxide (NO) in flue gases at low temperature, the selective non catalytic reduction (SNCR) by photochemical reaction was examined at room temperature. Vacuum ultraviolet irradiation of 172 nm was used as power source of photochemical reaction. Using NO/O_2/N_2/NH_3 gas mixture, the effects of NH_3/NO molar ratios (MR), valid number of photons, and oxygen concentrations on NO removal were investigated. An approximate 99% NO removal was attained at room temperature, however, N_2O was generated from NH_3. NO oxidation by VUV was examined to inhibit N_2O generation under NO/O_2/H_2O/N_2 system. Almost all NO was converted to HNO_3 at room temperature.

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Selective non-catalytic reduction of NO_X by activated ammonia injection has been developed to broaden and lower the narrow temperature window for de-NO_X. A temperature window enlargement of 150℃ was achieved at the lower boundary of the window using activated ammonia injection. In this study, the reaction mechanism for de-NO_X was considered by the measurements of the chemical composition of activated ammonia, the verification de-NO_X experiments, and the detailed kinetics simulation. A major chemical species of activated ammonia is molecular hydrogen. The effect of molecular hydrogen on de-NO_X reactions was investigated by using an NH_3/H_2 gas mixture in the temperature range of 500℃-850℃. This clearly indicated that hydrogen played a key role in the expansion of the temperature window. The reaction mechanism of de-NO_X was described using a detailed elemental kinetic model. This model suggested that molecular hydrogen produced key radical species for de-NO_X reactions, such as HNO, NNH, and NH above 600℃, which were promoted NO_X reduction at lower temperatures.

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In recent years, microorganisms contained in ship ballast water have been identified as vectors for the destruction of marine ecosystems. To control such microorganisms, various techniques are being developed and tested. As part of this effort, we propose a technique that uses underwater shock waves driven by a gas-imploding detonation. Previously, we have reported characteristics of pressure generation at the implosion center of an imploding detonation. We examined how the maximum pressure, rise time, and half-width time of underwater shock waves affected the mortality rate of microorganisms (Anemia salina). The mortality rate of Artemia salina was increased by shortening the rise time of the pressure waves while increasing the maximum pressure and half-width time of underwater shock waves.

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Plasma sterilization has a potential as an alternative method against conventional sterilization methods because it enables to operate at low temperature and the cost is low. In this study, we developed a small size sterilization device using a contact lens case. The sterilization performance and plasma characteristics were investigated in air and water. Bacteria spores were sterilized in 20 min in air and in 120 min in water. The plasma generated NO_X which is considered as a main factor for the sterilization. The reason why the sterilization time was long is probably caused by that reactive species were transported by mainly diffusion.

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Red tide microalgae in the ocean, cause a various influence on human society as well as marine ecological system, and these influence tends to expand with global warming. It was subjected to systematic experiments on Heterosigma akashiwo using underwater shock wave that is driven by a propane-oxygen imploding detonation. As a result, by underwater shock waves treatment, we achieved 100% mortality rate Heteroshigma akashiwo. The mortality rate of Heterosigma akashiwo was found to be dependent on the maximum pressure of the underwater shock waves.

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To recycle glass fiber reinforced plastic (GFRP) discarded as industrial waste, we have proposed a process that produces porous glass fiber-reinforced ceramics by mixing clay and crushed waste glass fiber-reinforced plastic (GFRP) before the mixture is fired. This study was aimed at the development of a turbid filtering material that can decrease the environmental pollution by exploiting the porous ceramic properties. Various specimens with different porosity distributions were made by changing the mixing ratio of clay and crushed GFRP, particle size of GFRP, and firing temperature of the mixtures. The permeability test and filtration test of suspension water containing kaolin powder were carried out on the samples. The results indicated that ceramics containing crushed GFRP at 60% of the total mass have high permeability and filtration ability. The ceramic may be used as a turbid filtering material.

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After the accident of Fukushima Dai-ichi Nuclear Power Plant (FDNPP), a large amount of radiocesium were deposited in the wide area and adsorbed strongly to the soil particles. To evaluate the environmental fate of radiocesium, it is necessary to predict the behaviors of soil particles by rain-runoff. In this study, the migration of soil particles in the Abukuma river basin, located in the vicinity of FDNPP, was analyzed by a hydrological/water quality model for the three years of 2009-2011. The hydrological model simulated well river flows in the basin both in flooding and non-flooding seasons. The water quality model could analyze the behaviors of soil particles: clay, silt, very fine sand and fine sand.

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In order to understand the impact of changes in power generation mix on photochemical pollution, we estimated the emission of pollutants from thermal power plants in Kansai region when all nuclear power plants were shut down. The influence of the emission changes on photochemical pollution in Osaka region was evaluated using WRF/Chem model under a typical mid-summer condition. The results show that NOx concentration increases around the emission sources and the changes are little in remote area. On the other hand, O_3 concentration decreases around the emission sources while increases in remote area.

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For the case where hazardous pollutants are emitted to the atmosphere, understanding the concentration field by pollutant source is important to protect not only our safety but also the surrounding environment from pollutant threat. In this study, based on Computational Fluid Dynamics (CFD), a data assimilation technique called the Variational Continuous Assimilation (VCA) method was utilized to estimate not only the concentration field but also the location and intensity of air pollutant source which continuously release to the atmosphere. The correction term added to the mass conservation equation by the VCA method is equivalent to the pollutant source. The VCA applications with different conditions in terms of sensor location, restriction of source location and observation conditions were compared. Restricting of source location, concentration field and source location was estimated more correctly.

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Turbulence plays an important role for predator-prey interactions in aquatic environments. In the present study, the flow structures promoting the pradator-prey encounter events in turbulence are explored by a numerical experiment. An instantaneous turbulent flow field is extracted from direct numerical solutions of the Navier-Stokes equations. Both the predators and prey are assumed to be passively carried with the frozen flow. It is also assumed that the predators have prey-detection distances R that are in the viscous subrange. The trajectory of each planktonic organism is computed in the Lagrangian frame so that the time and position of the pradator-prey encounters can be detected. The numerical experiment shows that the strain rate of the velocity filed is the primary factor in controlling the encounter events.

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In order to prevent global warming, air conditioning system using a natural refrigerant is desired. In this paper, helical screw expander is adapted to the air cycle cooling system. Using the simulation method, influences of the operating conditions and the design conditions on the temperature drop and the output characteristics of the expander are investigated. As a result, effects on the operating conditions and design conditions due to internal leakage losses and flow losses are revealed, and the optimum values are indicated in each operating conditions and the design conditions.

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This study is concerned with the development of a hollow micro-hydraulic turbine excellent in foreign matter passage performance. The runner has a circular hollow around the central (rotating) axis so that foreign matter included in water can easily flow without blocking the turbine. The laboratory experiments are conducted to investigate the turbine performance. Though the turbine efficiency decreases with increasing the hollow ratio e when ε>0.25, it remains unchanged when ε≤0.25. The hollow of the runner effectively heightens the passage performance of the polyester fibers entrained into the turbine. The developed micro-hydraulic turbine of ε≥0.375 is not blocked by the fibers and maintains its function.

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This study examined the performance of a solar collector with a parabolic mirror mounted vertically on walls. In order to simplify the system, in does not have sun tracking function and focuses on hot water supply only during winter which dominates heat demand. The objectives are to design the parabolic concentrator by simulations and to demonstrate the heat recovery by experiments. The inclined angle and the focal length of the paraboloid are the design parameters. Since the parabolic mirror does not truck the sun, there should be the optimal settings of the design parameters which maximize the thermal energy collection during winter season. The simulation results indicated that the inclined angle of 25 ° and the focal length of 95 mm would be optimal, based on which the proposed collector was made and tested outdoors. The experimental results showed that the temperature of the hot water actually gained 45.8 degC. In contrast, the same collector without parabolic mirror attained only 30.9 degC of the hot water.

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There has been recently an increasing introduction of solar power generation systems. However, the power generation capacity of a solar panel depends on the installation area and the radiation view factor caused by the relative position between the solar panel and the sun. So far, for the range of investigated plant shoots, the configuration of a solar panel was optimized in order to maximize the light receiving density and an increased light density was achieved. However, since until now it was not possible to simulate large plants such as trees, the relationship between the light receiving characteristics and the growth process of a plant was not clearly understood. In this paper, the relationship between the light receiving characteristics and the growth process of large plants is determined by modeling the plant shoot and using genetic algorithm together with L-system.

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A fuel cell operating at room temperature uses platinum as catalysts. It is better to replace the platinum for catalyst to other substance due to cut cost of fuel cell off. And then, the electrolyte is also needed to be changed to other substance because the catalyst might be corroded by the electrolyte. In this work the ager is adopted for the electrolyte to prevent corrosion of the catalyst. Evaluation is conducted using a new fuel cell whose power density is improved to be 40 %.

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The throwing type thermoelectric generator was developed in our previous work, but there was a large temperature difference between the cooling water and the thermoelectric element. In this work, the flow pattern for the cooling water was modified to make velocity of the cooling water up for important of the heat transfer coefficient between the cooling water and the thermoelectric element. The improvements were confirmed to be 24% for temperature different and 24% for electric power out put.

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The development of energy systems based on distributed generation has become an important target in Japan after the Fukushima Daiichi nuclear power plant accident. Moreover, in regions with cold climates, such as Hokkaido, heat supply must also be taken into account. This study aims at the development of an optimal energy system based in the introduction of renewable energy in order to supply power and heat to the Teuri-Yagishiri Island in Hokkaido. It is assumed the introduction of solar power and wind power generation, together with heat pumps and heat storage tanks for heat supply. The system is modeled and studied from both economic and power quality points of view.

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