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YOSHITOMO HANAKUMA
1998 Volume 24 Issue 3 Pages
357-364
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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Technologies of nonlinear process modeling for industrial use have been developed in petrochemical plants. In this paper, the importance of nonlinear process dynamics modeling is explained and its applications in process control system design using a physical approach, a NARMAX model approach, a neural networks approach, a chaotic time-series analysis, a discrete Volterra series model and an extended Wiener series model with discrete Laguerre filters are presented.
The future tasks of nonlinear process modeling for industrial use are discussed.
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KAZUYA IJICHI, YOSHIMITSU UEMURA, HIDEKAZU YOSHIZAWA, YASUO HATATE, KU ...
1998 Volume 24 Issue 3 Pages
365-369
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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Type C particles on the Geldart's Map are characterized as cohesive and usually less than 20 μm. It is difficult to establish good fluidization, because the large external surface area combined with low mass tends result in to large attractive forces. The fluidization of type C particles has recently been studied as fine particles are applied in various fields of industry. In the present study, fluidization of type C particles in a draft tube spouted bed with a converging nozzle is investigated. As a result, it is found that type C particles are fluidized by appling the effects of reducing pressure of a converging nozzle. The particles used in the experiments were two kinds of alumina powders with diameters of 7.9 and 14 μm.
In addition, solids circulation rate, downward gas flow rate in the annular region and pressure loss in the draft tube were measured by changing gas throughput and bed height as operating parameters, and also by changing tube separation distance and converging nozzle diameter as design parameters.
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MASAMI HASEGAWA, KEN TOYOKURA
1998 Volume 24 Issue 3 Pages
370-373
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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Unsaturated brine of a known concentration of NaCl was added into a solution from a NaCl fluidized bed crystallizer to make unsaturated state and the change of fines in the solution was studied against operational conditions of unsaturation and agitation time. The population of fines counted after they became visible by standing of the solution in a supersaturated states for 24 hours is correlated with the product between unsaturation and agitation period, and the dissolution coefficient is obtained. A dimensionless design chart of product crystal size, production rate, suspension density of crystals in a crystallizer, average nucleation rate and average growth rate is proposed, and an industrial application for manufacturing products having desired crystal size by the partial dissolution of fines is discussed.
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YASUNORI SHIBATA, KAZUO OZASA, KAZUO TSUZURA, HIDETOSI IZUMI
1998 Volume 24 Issue 3 Pages
374-379
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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Use of granular solidified coal ash as a road base material has been studied to facilitate the large scale utilization of powdered material. The proposed technology of producing granular solidified coal ash includes steam curing combined with different unit operations. Investigations on the technological and quality control aspects make clear the followings :
(1) A proper technology for large scale processing may consists of the following steps : kneading of coal ash with water around its plastic limit, low pressure molding, steam curing and crushing.
(2) A road base material of good quality can be produced in large qualities from coal ash of fixed CaO content and unburnt carbon content. Further processing includes mixing with the amount of water based on the size and the time change degree of the consuming power in kneader, kneading and molding. The temperature of the kneading water should be adjusted to the ambient conditions.
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TATSUJI SHIZAWA
1998 Volume 24 Issue 3 Pages
380-384
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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An on-line automatic resin pellet external testing and automatic selecting control system for substandard products has been developed. The system utilizes the advantage of image processing technology and the testing targets are as small as 50100 μm foreign substances and discoloration substances in the pellets.
The testing system includes pellets sampling from a plant, testing of sub-standard pellets, and subsequent disposal of tested pellets, and is fully automatic.
The resin pellets are transported automatically to product silo or sub-standard product silo by the selecting control system based on the external testing result. The systems contribute to the stability of quality control and improvement of operation and labor saving.
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YUTAKA YAMAZAKI, HISATOYO YAZAWA, YUSHI HIRATA
1998 Volume 24 Issue 3 Pages
385-391
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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The hardness of an ice layer formed on the inner wall of a crystallizer for freeze concentration has been investigated on the basis of the torque required for scraping the layer. A torque increase observed in first scraping the ice layer growing from the wall decreased with increasing rotational speed and the concentration of solute in ice. After that, variations of the torque required for consecutive scraping were classified into two patterns. In scraping the ice layer formed in water and cephalosporin c sodium solution, the torque increased gradually with time, and finally scraping became impossible. On the other hand, the torque hardly changes with time for sodium chloride, glucose and isopropyl alcohol aqueous solutions, and the ice layer was readily scraped. These findings show that ice layers formed are hard in the former solutions but soft in the latter solutions. However, it has been confirmed that the ice layer formed in cephalosporin c sodium solution changes from a hard state to a soft one by adding isopropyl alcohol to the solution. The properties of the ice layer are investigated by microphotograph observation and DSC measurement. The results suggest that the hardness of the ice layer depends on the composition of the trozen body.
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TSUTOMU OHISHI, SETSURO HIRAOKA, YOSHIHITO KATO, YUTAKA TADA, JIN YANO ...
1998 Volume 24 Issue 3 Pages
392-396
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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The solid-liquid mass transfer coefficient
kL of EGSTAR agitator, which has been practically used as a bioreactor, was measured and compared with the coefficients of some conventional impellers. Under operation conditions above the critical rotational speed for complete suspension, the solid-liquid mass transfer coefficient depends only on the power consumption per unit volume
Pv regardless of the impeller geometries. The power consumption of the liquid circulation type impellers, propeller and pfaudler, for the complete suspension was lower than that of the high shear type impellers. The Maxblend impeller has the largest
kL among the impellers used at low rotational speed. The EGSTAR agitator, in which solid particles are packed, has larger
kL than the other impellers at low
Pv.
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TADAHIRO HAGITA, TERUO ONO, YUJI FURUKAWA, HIDEKAZU YOSHIZAWA, YOSHIMI ...
1998 Volume 24 Issue 3 Pages
397-401
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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To investigate the characteristics of spray etching, which has been used for producing precision metal goods, spray etching tests of 42 Alloy using ferric chloride solution were carried out. By varying fundamental operating factors (ferric chloride concentration, etchant temperature and spraying pressure), we studied their effects on etch rate and etch factor which is an index of accuracy. The etch rate showed a convex curve against ferric chloride concentration. The higher the concentration, the smoother the sample surface. Spraying pressure had a significant effect on etch factor. Higher spraying pressures improved etch factor. The activation energy is 29 kJ/mol when the photo-resist hole diameter is 250 μm.
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TAKATOSHI SETO, KENTARO HIRATA, MASAKI ODAGIRI, MAKOTO IMANARI
1998 Volume 24 Issue 3 Pages
402-406
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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Separation of ethylene glycol and sodium salt of serine is important in the processing of serine by the Strecker method using glycol aldehyde produced from ethylene glycol. The separations were successfully carried out using a simulated moving-bed four-zone type adsorber which was composed of a sodium salt of strongly acidic cation exchange resin. The moving-bed adsorber used was slightly different from a conventional one in the manner of setting up Raffinate 2. Separation of this type was simulated by calculations using an analytical solution of steady state rate equation concerning the adsorption and desorption of the ingredients and the moving bed. The condition needed for separation in the four-zone type with Raffinate 2 was discriminated, being generally coincident with the conventional condition of β value.
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KUNIO SHINOHARA, KATSUYA UENO, TOMOYUKI UCHIYAMA
1998 Volume 24 Issue 3 Pages
407-412
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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A wettability measurement was conducted as one of the physicochemical properties of surface composite fine particles. The particles were prepared by high-speed gas impact blending. To evaluate the wettability, the capillary rising velocity of water in a packed bed of composite fine particles was measured continuously by means of an electronic balance. This measurement is based on Washburn's theory on the penetration rate.
The experimental results showed that the wettability of the packed bed increases with the coating ratio of the hydrophilic fine particles over the composite surface. It also increases with increasing voidage, which reduces the effective penetration area, and decreases with sinking extent.
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TAMIO NODA
1998 Volume 24 Issue 3 Pages
413-417
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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It is suggested that methyl mercaptan is decomposed to methyl sulfide and hydrogen by reaction with the α-iron hydroxide, and then the methyl sulfide combines with sulfur crystal and the hydrogen changes into water by the chemical reaction with theα-iron hydroxide. A deodorant filter was made by treating porous metallic iron with an aqueous solution of L-ascorbic acid, iron (II) sulfate and calcium hydroxide aqueous solution to deposit the iron ascorbate and thea-iron hydroxide on it. Then the deodorant filter was exposed to the hydrogen sulfide to yield the sulfur crystals on the surface of the deodorant filter. The methyl mercaptan removal capacity of the deodorant filter was studied with repetition of removal tests. Results show that the methyl mercaptan removal capacity of the deodorant filter is a little smaller than that of conventional granular activated carbon.
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DAISUKE TANEDA, HITOSHI TAKAHAGI, SYOUICHI AOSHIKA, NOBUYOSHI NAKAGAWA ...
1998 Volume 24 Issue 3 Pages
418-424
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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The characteristics of elutriation of fine particles and the effect of operating conditions on elutriation in a Powder-Particle Fluidized Bed were clarified using silica sand and activated alumina beads with a diameter of 550, 780 and 920μm as coarse particles, and Al(OH)
3 with a diameter of 3 and 15μ m as fine particles. Fine particles were fed continuously to the bed and data were obtained under steady state. The elutriation rate constant of fine particles increased with an increase in gas velocity and the size of fine particles, and decreased with an increase in the size of coarse particles. However, it was not affected by the hold-up of fine particles. In the case of using fine particles having particle size distribution from 1 to 70μm and average particle diameter of 15μm at a gas velocity of 0.8 m/s, measurements of particle distribution of feed particles and entrained particles revealed that particles with a diameter over 30μm entrained selectively from the bed and particles with a diameter less than 8μm were held easily in the bed. It was suggested that this phenomenon could be explained by the relationship between cohesion forces of fine particles and the pressure of coarse particles based on the motion of coarse particles in the bed.
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MANABU KANO, KOICHI MIYAZAKI, SHINJI HASEBE, IORI HASHIMOTO
1998 Volume 24 Issue 3 Pages
425-430
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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In order to control product compositions in a multicomponent distillation column, the composition estimated from measured tray temperatures is used. In this paper, inferential models of product compositions are constructed using Partial Least Squares regression, on the basis of steady-state and time series temperature measurements. The accuracy of the estimation is greatly improved by using a dynamic model. It is also found that the use of past temperature measurements is effective for improv-ing the performance of the inferential model. From the detailed dynamic simulation results, it is found that the cascade control system using the proposed inferential model works very well.
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SHIRO TAKASHIMA, JIRO KATAYAMA, EIJI OBATA, HIROSHI TAKAHASHI
1998 Volume 24 Issue 3 Pages
431-436
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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Experimental study on the local heat transfer characteristics around a heater rod installed horizontally in a circulating fluidized bed 4 m-high and 0.1 m-i. d. was carried out under fast fluidization conditions. Air and FCC catalyst particle were used as a gas-solids suspension. The heater rod was electrically heated with 10μm-thick nickrome foil heater on a wooden base rod of 10 mm-o. d. In order to understand particle motion, a glass pipe was mounted to simulate the heater rod and the particle motion on the surface of this glass pipe was observed from inside of the pipe using a borescope and CCD camera.
The result showed that heat convection around a pipe is influenced by solid fraction in the bed and particle motion on the heater surface, such as collision against the lower surface, formation of a stack on the upper surface, and downflow along the wall caused by core-annulus flow. The correlation between the mode of particle motion and the local heat transfer around a pipe is interpreted based on the results obtained.
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TADAO NIWA, MIHO KATAOKA, HIROKAZU NISHITANI
1998 Volume 24 Issue 3 Pages
437-444
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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A batch processing production scheme using mobile vessels has been created by decomposing functions of unit operations in the conventional batch processing plant from the viewpoint of operational tasks and reorganizing the batch process as a sequence of operational tasks. This production scheme, called a pipeless batch plant, is expected to be used in the coming generation because production can be accomplished in a flexible manner. The dynamics of this plant are very complex because it includes many design problems which require solving; such as determining the number of vessels, stations and AGVs, layout of stations, vessel moving rules and job scheduling.
In this paper, the system concept and required system components are reviewed first. Then methods for modeling and simulation of the complex system are proposed to analyze the system performances. The simulation system developed entails the modeling of a real plant, its simulation and evaluation of subsystems.
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IZUMI TANIGUCHI, JUNICHIROU KAWABATA, KOICHI ASANO
1998 Volume 24 Issue 3 Pages
445-450
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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Numerical analyses of mass transfer of a binary solution drop with diffusive surface mass suction or injection were made by use of a finite difference method for Reynolds numbers
Rep=1200, Schmidt numbers
ScAC=0.52.0 and
ScBC=0.52.0 and surface mass suction or injection ratios.φ=-0.20.2. The diffusion fluxes of a binary solution drop are affected by
Rep,
ScAC and
ScBC as well as mass suction or injection ratios, φ. A new correlation for the effect of diffusive surface mass suction or injection on the diffusion fluxes of a binary solution drop is proposed in terms of the transfer numbers in ternary system.
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TAKASHI SASAKI, SHIGEHIKO YAMAMOTO, IORI HASHIMOTO
1998 Volume 24 Issue 3 Pages
451-457
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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We have developed an algorithm that automatically executes step response tests for defining position correspondence, which is the most important tuning factor in basis weight profile control for paper machines. The algorithm is composed of two parts. One is the part that defines the slice bolts that are manipulated and their manipulation direction by using neural networks that have lateral inhibition. The other is the part that optimizes the amount of manipulation by using wavelet analysis.
We show an example where step response test was executed automatically by actually using this algorithm and show the effects of this algorithm.
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ICHIRO KOGUMA, MASANORI NAKAMURA, KYOICHI SAITO, KAZUYUKI SUGITA, SATO ...
1998 Volume 24 Issue 3 Pages
458-461
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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A diethylamino (DEA) -group-containing polymer chain was grafted onto a porous polyethylene membrane in the form of a hollow fiber by radiation-induced graft polymerization of an epoxy-group-containing vinyl monomer (GMA), followed by a reaction of the epoxy group with diethylamine. Bovine serum albumin (BSA) was multilayered up to six layers by the permeation of a BSA solution through the pores of the DEA-group-containing porous membrane. A chromatogram of DL-tryptophan was obtainable by the injection of a racemic Trp solution into a BSA-multilayered membrane acting as a stationary phase. The selectivity coefficient, defined as the retention time ratio of L-Trp to D-Trp, increased with the degree of BSA multilayer binding, and remained constant irrespective of the flow rate of the mobile phase because of a negligible diffusional mass-transfer resistance.
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SATOSHI MACHIDA, TOMOHIRO AKIYAMA, JUN-ICHIRO YAGI
1998 Volume 24 Issue 3 Pages
462-470
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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Methanol is attracting worldwide attention as an important industrial raw material for chemicals such as formaldehyde and MTBE. It can be not only used as additive to gasoline, but also a clean fuel without emissions of NOx and SOx. Thus, great demand for methanol is expected in the future.
The objective of this study is to discuss the possibility of energy savings in methanol production systems by means of the exergy concept giving information of the quality of energy. As a result of evaluation of the conventional system, it is found that the steam reforming of methane accounts for about 70% of the total exergy consumption with the least efficiency of all processes. The results showed that improvement of the steam reforming process is most effective for saving energy. On the other hand, comparison of the obtained exergy consumption with a theoretical value showed quantitatively room for improvement in the methanol production process ; total exergy consumption of the conventional methanol production system is 44 times as large as the theoretical minimum exergy consumption of the direct synthesis reaction, and 4.5 times as large as that of the conventional two step reaction system ofsteam reforming followed by methanol synthesis from CO and H
2.
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NORIHIRO WATANABE
1998 Volume 24 Issue 3 Pages
471-475
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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In a refuse incinerator, a relay feedback controller is equipped to keep the vapor flow rate in a neighborhood of a constant value. Bifurcations and chaotic phenomena are observed under this control system. In this paper, numerical simulations are carried out using a model of the refuse combustion control system. It is confirmed that these phenomena are caused not by the characteristic of the refuse combustion, but by the structure of the control system that adjusts a rectangular input by the on-off signal of the relay with a hysteresis. In this system, the value of the vapor production rate has a maximum value when the system is a one-periodic state. However, it is also shown that the value is fairly high in some cases even if the system is chaotic.
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HITOSHI TAKAMI, NAOKI NODA, YOSHINORI ITAYA, HITOKI MATSUDA, MASANOBU ...
1998 Volume 24 Issue 3 Pages
476-480
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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A porous ceramic burner has already been proposed for high turn down ratio in kerosene combustion. However, at higher loads, considerable amounts of NO
x are found to be emitted. This present paper proposes a two-stage air supply system for reducing NO
x emitted from kerosene combustion on a porous ceramic burner, and other combustion characteristic of this burner are experimentally studied.
It has been confirmed from experimental works that by introducing two-stage air supply the fuel lean limit is lowered to as low as 0.2 equivalence ratio and that the stable combustion area ranges from 2.0 to 11.5 kW. Then the corresponding turn down ratio achieves 5.8. Since the ratio of primary air to total air greatly influences not only the temperature distribution in the burner but also the soot formation, the CO concentration and the NO
x emission at the exit of the burner, this value is regarded as an important operating factor in this burner. By using the optimum ratio of primary air to total air, the NO
x emission is found to be approximately one-quarter to that of the emission with single-stage air supply.
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MASAHIRO FUJIWARA, KEISUKE FUKUI, SYOJI HIROTA
1998 Volume 24 Issue 3 Pages
481-485
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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The effects of gravity currents on longitudinal and transverse vortices between horizontal parallel plates of which temperatures change discontinuously in the lateral direction are investigated from experiments by means of a flow-visualization technique and measurement of temperature fluctuation. The flow fields are found to be classified into three different flow patterns : flow type I consists of only transverse vortex rolls, flow type II consists of mixed longitudinal and transverse vortex rolls, and flow type III consists of only longitudinal vortex rolls. These flow patterns can be classified by using the degree and flow direction of the gravity currents and Reynolds number. Gravity currents promote a formation of the flow field of mixed longitudinal and transverse vortices at low Reynolds number.
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NOBORU SAITO, MASAAKI YOKOTA, AKIRA SATO, NORIAKI KUBOTA
1998 Volume 24 Issue 3 Pages
486-490
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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Growth behavior of a single sodium chloride seed crystal mounted on the bottom of a flow cell was observed by an optical microscope. When a small crystal (a few to 50μm), suspended in the solution, attached by chance to the surface of the seed crystal, macro-steps appeared on the crystal surface in succession. These macro-steps were combined to a large macro-step, which was left behind by the following macro-steps. At this moment of over-passing, liquid inclusion (s) was formed. This formation was observed not only on the surface where a small crystal adhered but also on any other crystal surface. The macro-steps are assumed to be formed by bunching of molecular size steps, which are generated from a dislocation caused by mechanical stress induced by adhesion of a small crystal. The instantaneous (up to several tens of minutes) growth enhancement is also observed. This enhancement is attributed to the number increase of molecular size steps. This type of liquid inclusion formation influencing lowering of crystal purity is pointed out to be important from an industrial point of view.
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SABURO WAKIZAKA, ISAO SEKIGUCHI
1998 Volume 24 Issue 3 Pages
491-496
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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To compare the difference of surface tension of asphalt in various penetration grades, the surface tension for 18 kinds of asphalt with penetration grades 60-80, 80-100 and 150-200 were measured. Furthermore, these asphalts are individually segregated into four components, and the relation between total surface energy (
Hs) and asphalt components are investigated using a statistical analysis. Penetra-tion grade 60-80 asphalt is found to have the largest value of standard deviation, and 80-100 and150-200 show almost the same value. The relation between each of the four components of 18 kinds of asphalt and
Hs are analyzed by use of a single regression analysis. It is found that asphaltenes have the largest correlationcoefficient value for
Hs. Also, the relation between four components and Hs are analyzed by use of amultiple regression analysis. From these data, it is clarified that asphaltenes had an influence onthis relationship. Furthermore, in order to investigate the influence of asphaltenes concentration in asphalt, 6 kinds of asphalt were selected and the surface tension for their malthenes components measured. Low surface tension for each asphalt is observed. It is indicated that the asphalt is influenced by asphaltenes concentration of more than 13-14%.
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IWAO AKIBA, SHINJI MIYAMOTO, HIROKATSU MASUOKA
1998 Volume 24 Issue 3 Pages
497-502
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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Crystallinities for three samples of crystalline polypropylene powders have been determined by a gas chromatographic method. These results are correlated with a simple equation.
Furthermore, Henry's law constants of five nonpolar solutes and four polar solutes in the crystalline polypropylene powders were measured at temperatures from 349.5 to 497.1 K by using a gas chromatographic method. Experimental data above the melting temperature of polypropylene are correlated with a method based on a corresponding states model recently proposed by Zhong
et al. (1997). The correlation was extrapolated below the melting temperature to get Henry's constants in the amorphous phase. Taking the crystallinity into consideration, the estimated Henry's constants are in good agreement with the experimental data.
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HIDEYUKI YASUMOTO, MASAYOSHI SASAKI, TAKASHI NIITSU, HAKUAI INOUE
1998 Volume 24 Issue 3 Pages
503-505
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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The effect of suspended particles on the tubular membrane filtration of dextran solutions is studied, and the permeation flux is measured. In the case of operation with a horizontal membrane module, the permeation flux decreases with increasing particle concentration for low fluid circulation rates, and for high circulation rates it increases with particle concentration.
On the other hand, in case of the up-flow operation with a vertical membrane, the permeation flux increases with particle concentration for all circulation flow rates.
The mechanism of the effect of particles on the permeation flux is discussed based on the behavior of particles in a tubular liquid flow.
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KAZUYA UEZU, MAKOTO NARISAKO, MASAHIRO GOTO, MUNEHARU GOTO, FUMIYUKI N ...
1998 Volume 24 Issue 3 Pages
506-508
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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Selective separation of copper and molybdenum with liquid surfactant membranes which contain 2-ethylhexyl-mono-2-ethylhexyl phosphonic acid (PC-88 A) as a carrier and L-glutamic acid dioleyl ester ribitol as a surfactant, was conducted in a Mixco extractor. The concentration profile of molybdenum along the column was measured. The experimental results are analyzed by the backflow model taking into account the interfacial reaction between molybdenum in the continuous aqueous phase and the carrier in the liquid membrane phase. The concentration profile for molybdenum in a dual-component solution along the column is successively simulated without using a special fitting parameter just by the interfacial reaction rate constant obtained in a previous batch-wise experiment.
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MASATO TANAKA, YOSHINARI TAGUCHI, YOSHIYUKI IGUCHI
1998 Volume 24 Issue 3 Pages
509-511
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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It is investigated whether composite particles composed of waste polymer and solid powder are able to be prepared by using a semi-chemical recycle method.
In the experiment, polystyrene pellets as waste polymer, dichloromethane as the solvent and magnetite as the solid powder are adopted. This solution of the dispersed phase was dispersed into fine droplets in the continuous water phase.
In the case of the lower impeller speed and the lower temperature for removing the solvent, composite particles coated with solid powder can be prepared. However, with increasing impeller speed and temperature, the dispersion becouse unstable and then the composite particles can not be prepared.
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YOSHITOMO HANAKUMA, TAKESHI TAKEUCHI, JUNZOU YAMAMOTO, EIJI NAKANISHI
1998 Volume 24 Issue 3 Pages
512-513
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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A method of detecting process abnormal signals using an improved method of skewness and kurtosis analysis which are used for fault diagnosis of arotary machine is developed. The method proposed in this study has the advantage of detecting online process abnormal signals in industrial use. It is applied to abnormal detection of the catalyst feed flow in a linear low-density polyethylene plant to confirm the design philosophy. The actual result indicates that the proposed method is effective in detecting abnormal process signals.
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AKIO NAKAYAMA
1998 Volume 24 Issue 3 Pages
514-516
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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As a result of experimental consideration on flow characteristics in a hydrogen lift pump (electrolytically-generated hydroden bubble-lift pump) and air lift pump, the following findings are clarified. A hydrogen lift pump begins pumping up of the liquid at a smaller gas volume flow rate aerated than an air lift pump. For the same gas volume flow rate aerated, the liquid flow rate in the hydrogen lift pump is larger than that in the air lift pump. This is under the assumption that the flow pattern of liquid and gas in a riser pipe of the hydrogen lift pump is bubbly flow which consists of bubbles with diameters of about 0.5 mm. On the other hand, the flow pattern in the air lift pump is slug flow with large bubbles. Namely, in bubbly flow much liquid is accompanied by small bubbles, as small bubbles have small slip velocity on liquid and gas phases.
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HIROMITSU MIYAKAWA, FUMIHIDE SHIRAISHI
1998 Volume 24 Issue 3 Pages
517-519
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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The effect of nonuniform activity distribution in a porous support on the apparent kinetic parame-ters,
Vmapp and
Kmapp, of a packed-bed immobilized enzyme reactor has been theoretically investigated.
Vmapp and
Kmapp increase with the increase of external diffusional resistance, regardless of the type ofnonuniform activity distribution. As the external diffusional resistance becomes significant, the apparent kinetic parameters became less dependent on the substrate concentration at the reactor inlet. Like the case of diffusional resistance or electrostatic field, the nonuniform activity distribution had a significant effect on
Kmapp.
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KOICHI TABEI, HAJIME INO, MASAO KURODA
1998 Volume 24 Issue 3 Pages
520-522
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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An axial mixing of liquid down stream flow in mobile beds is studied on the basis of the dispersion model. The axial dispersion coefficient of liquid is evaluated by a pulse response method experimentally. The values increase with the gas and liquid velocities, the packing density, the diameter of the column and the liquid viscosity increased, and decreased when the diameter and the packed height of the packings increased.
It is also found that the liquid dispersion coefficientis closely connected with the packings dispersion coefficient. The values of the liquid Peclet number are correlated to the particle Peclet number.
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KENJI SHIMIZU, KATSUO TSUKAMOTO, SHIGENAO MARUYAMA, YASUSHI KOHNO, NOB ...
1998 Volume 24 Issue 3 Pages
523-525
Published: May 10, 1998
Released on J-STAGE: November 12, 2009
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The process of secondary nucleation and the subsequent crystal growth process have been investigated both by fast-dynamic light scattering method and optical microscop under the micro gravity in drop shaft. It was found that the movement of crystals formed in solution could be suppressed completely in micro gravity, in which collision and agglomeration phenomena did not take place. No nucleation occured except for the seed crystal surface. Also it could be measured the number and size of produced crystals with order of nano-meter by fast-dynamic light scattering method.
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