The thermogravimetric analysis is studied to investigate the thermal stability and the chemical kinetics of waste newspaper. The thermal degradation and the kinetic parameters (Order of reaction, activation energy and pre-exponential factor) are determined at different heating rate by using TG/DTA data. The heating rates used in this study are 5, 10 and 20 K/min respectively. The decomposition results could be modeled by an Arrhenius equation. The least square technique is used for determining kinetic parameters. Depending on the heating rate, the activation energy and the order of reaction vary from 8.15 to 23.42 kJ/mol and 0.56 to 0.79 for newspaper (moisture free basis). Next attempt is to use waste newspaper as a raw material for converting it into bio-oil via pyrolysis. The yield of bio-oil is increasing with increasing the pyrolysis temperature. The average maximum yield of bio-oil 39% is obtained at the pyrolysis temperature of 500°C. Pyrolysis gases have also been analyzed in a gas chromatography to measure the concentration of hydrogen gas at increasing temperatures and also checked the effect of heat keeping time, defined as the time with a constant temperature in the reactor to the gas yields. The pyrolysis temperatures 500, 700, 900 and 1000°C and heat keeping time 0, 30 and 60 minutes are applied in this study. Maximum about 53 vol% of H₂ is observed by applying the temperature of 900°C and heat keeping time of 60 minutes.

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A typical ceiling-mounted ventilator consists of a cylindrical fan unit and a rectangular box as an outer cover. When the box is appropriately closed by an orifice plate in front of the fan, the space enclosed by the box and plate acts as a sound resonator. In the present study, the performance and physical aspect of this resonator are investigated experimentally using a model of a rectangular chamber containing an internal cylinder placed in an infinite circular duct. The sound transmission loss of the chamber is measured while varying the chamber length and the inlet length. The experimental model verified the effect of an actual ventilator. Two resonances appear in the frequency range of interest. These resonance frequencies are determined using a relatively simple estimation. In addition, for modulating the chamber property, a thin circular plate or a thin cylindrical pipe, called a “separator,” is attached to the chamber. The performance of the separator, which modulates the resonance frequency, is examined. If the orifice plate and the separator are combined and arranged appropriately, they can promote sound attenuation in actual ceiling-mounted ventilators.

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In order to reduce environmental loads such as primary energy consumption and carbon dioxide emission, optimizing energy utilization systems in terms of the effective utilization of thermal energy, is an unavoidable process. We considered the effective introduction of the cogeneration system (CGS) on Keio University Shonan Fujisawa Campus (SFC) under the condition of power transmission to another campus. First of all, we clarified the energy demand into categories of power, heating, and cooling, in the previous paper. The energy utilization systems, including the CGS, are assessed on the exergy balance between demand and supply, in the second step. Finally, we examined the effectiveness of the systems by maximally utilizing the exhaust heat on SFC, and the power transmission to another campus. As a result, the annual primary energy consumption and carbon dioxide emission could be reduced by 8% and 26% respectively compared to the existing system. Furthermore, the peak power load on the commercial grid could be leveled through the year, by the proposed manner of introducing and operating the CGS.

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In designing the high head pump turbine runner, the vibratory stress caused by the interaction force between the guide vane and the runner vane should be exactly predicted. This paper, first, presents the analysis method to calculate the vibratory stress of the tuned runner by the cyclic symmetry method. And the simple procedure to estimate the vibration response of the mistuned runner is also proposed. Second, the response analysis of the actual runner is carried out, and some calculated results are shown to explain the typical vibration characteristics of the tuned and mistuned runner. It is shown that the vibration modes of the tuned runner include many Fourier components, which satisfy the resonant condition. In the resonance of the in-phase mode, the almost complete traveling wave is formed, while the non-moving points appear at the vane position on the crown and the band in the resonance of the out-of-phase mode. It is also shown that the mistuning effect of the runner is not so large. Lastly, the measured and calculated vibratory stresses of the actual runner are compared to verify the validity of the proposed method.

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The dynamic of a micro-grid consisting of an engine generator and sixteen fuel cells was clarified by the transfer function model using actual data from power generators. The micro-grid was composed of a 3kW engine generator and 1kW fuel cells, and the dynamic characteristics of the grid were analyzed using the energy demand model in February of a cold region. Consequently, the settling time (Time taken to converge on ±5% of the limit of an output target) of a micro-grid is 15 seconds from 10 seconds. The control parameter of a fuel cell system is significantly influenced by the settling time and overshooting of a micro-grid. Since any excess and deficiency in electric power can respectively be covered if two or more fuel cells are connected with a grid, the instant electric power demand load peak can be distributed. Compared with the number of fuel cells required when installing independently, the number of installations can be reduced for a micro-grid system.

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An air-to-water CO₂ heat pump is used in combination with a domestic hot water storage tank, and the performance of this water heating system is affected significantly not only by instantaneous ambient air and city water temperatures but also by hourly changes in domestic hot water demand and temperature distribution in the storage tank. In this paper, the influence of operation conditions such as outlet water temperature during operation and inlet water temperature for shutdown of a CO₂ heat pump on the performance of a water heating system is investigated by numerical simulation. The trade-off relationship between the system efficiency and the volume of unused domestic hot water as criteria for the system performance is clarified in relation to the operation conditions. The influence of seasonal changes in ambient air and city water temperatures on the trade-off relationship is also clarified.

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Until now, perfluorinated proton exchange membrane (PEM) has been widely used as the electrolyte for PEMFC. As long as the perfluorinated OEM is used for the electrolyte, both the cell performance and durability of OEMFC strongly depends on the water content in its electrolyte, since the high conductivity of electrolyte is presented only at the sufficient hydrated state. On the other hand, pre-humidification of fuel and oxidant gases complicates the PEMFC system and prevents it from cost reduction. Therefore, in order to achieve simultaneously the high performance, durability and cost reduction of PEMFC, it is thought to be a best way that both the anode and cathode catalyst layers will be highly humidified only by the water produced through an electrode reaction without pre-humidification of fuel and oxidant gases. Although the management of the vapor permeation rate through gas diffusion layers will be most effective for such a self-humidified PEMFC, it isn't so easy to achieve it in the wide range of current density.

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The influence of the addition of cationic surfactant (Ethoquard O12) with a concentration of 50ppm on water flow around a cylinder at Reynolds number Re_S=64∼600 was investigated by using LDV and PIV. At Re_S=300, the flow with the surfactant formed a stagnant zone in front of the cylinder, which appeared periodically and expanding along the axial direction. The period of the appearance was about 120 [s]. The periodical flow structure was visualized by the measuring the velocity fluctuation. The development of the stagnant zone in front of the cylinder induced the expansion of a low speed flow region near the side of the cylinder.

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The objective of this work was to use coal as the raw material to prepare activated coke (AC) catalysts of industrial-scale size for SO₂ removal from flue gas and to find the optimal additives and preparation methods. Results showed that activated coke with metal loaded was a suitable method, and that the activated coke catalysts, prepared by loading with CoCl₂ or CaCO₃ and finally calcining at 700°C, exhibited the best desulfurizing property with a sulfur retention of about 98.6mg-SO₂/1g-AC at a reaction temperature of 80°C. Also, the effects of H₂O content in the flue gas, reaction temperature and space velocity on the desulfurizing property were investigated to determine optimum operating conditions. An H₂O content of about 10% was appropriate for catalysts in this work. In the temperature range 70∼110°C, the catalyst showed good performance for SO₂ removal and was gradually deactivated at temperatures above 110°C. Space velocity exhibited an optimal value of 800 h^-1. The kinetic behavior varied with space velocity and the desulfurizing property was controlled by adsorption at space velocities below 800 h^-1, and controlled by catalytic reaction at space velocities above 800 h^-1.

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This paper studies the problem of inertia matrix identification using the adaptive tracking control proposed by Ahmed et al. The singular perturbation method and the averaging method are applied to analyze the linearized closed loop systems. Then a combination of periodic commands, PD gains and adaptive gains are established such that all estimates simultaneously converge to true values in local with a specified convergence rate.

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A constitutive equation for elasto-plastic damageable solids is formulated by using Drucker-Prager's equivalent stress to analyze the damage failure behavior of concrete structural elements reinforced with carbon fiber sheets. The forumulated constitutive equation is implemented in the two-dimensional finite element program to simulate the experimental results. The constitutive equation is identified by using the uniaxial, compressive and tensile test results for concrete and carbon fiber sheets. The finite element analyses are carried out for real-scaled cantilever RC slabs with and without carbon fiber sheets. The calculated results are compared with the experimental results to illustrate the validity of the proposed method of analysis.

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The possibility and applicability of thermal recycling of waste PET-resin have been investigated in the open atmospheric operation by supplying PET-resin powder as an auxiliary or additional fuel to the proposed twin-fuelled burner. In the preceding experiments, flow characteristics and burning processes of PET-particles in the proposed burner were investigated using PIV/PTV measurements. Appearances of flying PET-particles were optically observed and analyzed by using the double-pulsed laser, and the particle diameter was evaluated as an equivalent diameter. According to the results, some of the key factors for reducing the unburnt rate of PET-particles were clarified. In this paper, by taking these factors into consideration, an experimental attempt to reduce unburnt particle emission in the PET-resin powder combustion is carried out by varying the diameter of PET-powder supply pipe. The results specify that the increase in the dispersion degree of PET-particles reduces certainly the unburnt rate of PET-powder.

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An air-cooling system of a small capacity of several kilo-watts using only water refrigerant as a non-CFCs (Chlorofluorocarbon) technology is examined. The experimental device consists of two stages. The first stage is composed of a vacuum pump and a vacuum chamber of about 60 L in volume. The second stage has two heat exchangers (the exchanger located outside the vacuum chamber is a dummy cooling load) and a water circulating pump. An air-conditioner indoor unit or a heater is used as a dummy cooling load. The temperature and humidity characteristics are measured at each place. Consequently, the ability to cool the room air is ensured by an air-cooling system using only water refrigerant. A new vacuum pump, that can exhaust a large amount of water vapor, is developed and its properties are measured. It seems that the engine-based vacuum pump performance is sufficient to drive the air cooling system with water refrigerant.

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In this paper, a countermeasure of pattern formation phenomena by using dynamic absorbers is investigated experimentally. An experimental equipment of a single degree-of-freedom pattern formation system with a pair of contact rotating rolls and a dynamic absorber are made. The experimental results are compared with the analytical results using approximated characteristic roots. According to the results of the experiments without a dynamic absorber, it is confirmed that the relation among the natural frequency of the system, the polygonal number and the rotating speed agree with the analytical results qualitatively. According to the results of the experiments using a damped dynamic absorber, the delaying effect of pattern formation is confirmed. Also, a good quantitative agreement between the experimental and analytical results is confirmed. According to the results of the experiments using an undamped dynamic absorber, it is confirmed that damping of a dynamic absorber is necessary to delay pattern formation phenomena.

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To burn PET-resin powder as an alternative or additional fuel and to realize effective thermal recycling of a great deal of wasted and recycled PET-resin, some practical studies have been made on the physical aspects of PET-powder combustion in the industrial burner. The results showed that a large amount of PET-powder up to about 80 % is exhausted without burn-up in the open atmospheric operation, whereas PET-powder is perfectly consumed in the high temperature in-furnace operation. Understanding of the relationship between the heating time and the unburnt rate of PET-powder is therefore necessary to get an important knowledge to reduce the amount of unburnt PET-powder. In this paper, the behavior of particle diameter is first modeled according to those experimentally measured, a particle-size histogram of PET-powder is then transformed into a particle-number profile by stepping the particle diameter at 0.01 μm intervals, and simple numerical prediction of the unburnt rate in the PET-powder combustion is finally attempted by introducing the parcel approximation. The results give good quantitative agreement between the unburnt rates of PET-powder measured experimentally and those predicted.

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We present a model to simulate the increase in sludge temperature during batch-type thermal pretreatment of sewage sludge. The semi-theoretical model is based on energy balance as a function of operating conditions, including non-ideal factors determined by fitting. The model was verified by comparison with the results of bench-scale runs. It predicted the relationship between the operating conditions and steam input with sufficient accuracy. The test plant needed more energy input than the ideal during operation owing to the influence of the heat capacity of the apparatus. To optimize the scale of the apparatus, we simulated the treatment of 10 t of sludge. The energy input was minimized with 10 runs of a 1-t apparatus if the heat capacity of the ancillary apparatus exceeds a certain threshold, and 5 runs with a 2-t apparatus if the heat capacity is below the threshold. The influence of the boiler's performance on energy input is small, but its effect on the heat-up rate of the sludge is large. A boiler with sufficient equivalent evaporation and rated pressure will shorten the operating time.

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In this study, the pyrolysis characteristic of waste paint dregs has been investigated by comparing with wood chips at 500°C, 700°C and 900°C with a laboratory-scale reactor. The results showed that the gaseous yield significantly increased for waste paint dregs than that for wood chips with increase of pyrolysis temperature. Therefore, it is possible to gasify waste paint dregs like wood chips at high temperature to obtain efficient combustible gas for a dual-fueled engine. And the behaviors of heavy metals in the waste paint dregs were also investigated. It showed that Pb was volatile, Ti and Zn were non-volatile in the temperature range of 500°C∼900°C. Then, demonstration gasification and power generation experiments were carried out by a plant of commercial scale, using waste paint dregs and wood chips as fuel. The results agreed with the laboratory experiments, namely the heating value of pyrolysis gas produced from waste paint dregs increased with increase of gasification temperature, while that produced from wood chips didn't increase significantly with increase of gasification temperature. Pb was also volatile as in the laboratory experiment. The power generator efficiency of the diesel engine was 34% when the energy input ratio of fuel gas produced from waste paint dregs was 60%.

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Small axial flow fans are commonly used to cool personal computers or workstations. Although various studies have been carried out to improve the performance and reduce the noise of larger axial flow fans, few cases have been released about small fans. This paper investigates the influence of design parameters of an impeller, such as the camber of the blade, the maximum camber point of the blade, the cross sectional structure of the blade, the skew angle of the blade and the roundness of the blade edge on performance characteristics and noise.

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A new low NOx combustor for kerosene-fueled micro gas turbine was proposed, and the combustion characteristics of prototype combustor were investigated. The new combustor consisted of a primary and a secondary combustion zones, and they were connected by a throat. In order to enhance the recirculation flow in a primary combustion zone, a swirler was set between the primary and secondary combustion zones. Combustion air was introduced through the swirler and forced to flow upward to the combustor bottom, from which the fuel spray was supplied through a nozzle. To achieve high combustion stability and low emission in wide fuel-air ratio, the optimum configuration of the primary combustion zone were investigated. The optimum one was found out by measuring the fundamental combustion characteristics such as lean combustion limit, flame luminosity, exhaust gas composition and combustion gas temperature.

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Though various types of eigenvalue solvers for rotordynamics exist, they only provide solutions for specific parameters, e.g., for several selected rotational speeds. Since these solutions are discrete, it is occasionally difficult for us to make continuous transitions depending on the changes in parameters.
Our tracking solver is capable of providing the continuous behaviour of the solution caused by a varying parameter. Letting the parameter be the time t, the solution is obtained as a time function λ(t) of a state variable λ which is regulated by the sliding mode control so as to be placed on an unknown exact path of f(λ,t)=0. Once the state variable starts from an exact initial value, the state variable consistently indicates exact values thereafter. The principle of this tracking solver is extended to a 2D orbital tracking solver for f(x,y)=0.
To demonstrate the effectiveness of this method, we selected several case studies; complex eigenvalue analysis, algebraic equations with exponential functions, a critical speed map, 2D drawing of resonance curves.

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