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Predecessor
Volume 18, Issue 1
Displaying 1-22 of 22 articles from this issue
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Eiji Izumoto, Susumu Kyotani, Toshimitsu Nakashima, Hideki Fukuda, Eij ...1992 Volume 18 Issue 1 Pages 1-7
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSTo maintain constant composition of triglyceride in the effluent from a microaqueous bioreactor using a filamentous fungus immobilized within biomass support particles as lipase catalysts, a feedforward/feedback control system with an online enzyme activity estimator was developed. Feed flow rate as a manipulate value is calculated from the improved glyceride-enzyme complex model. The parameter in the model, enzyme activity, is adjusted repeatedly by the on-line estimator, in which the discrepancy between observed triglyceride data and calculated values is minimized by a trial-and-error method. To evaluate the performance of the control system, both simulation and experimental studies of the uncertainty of model parameters such as the deactivation constant and initial enzyme activity, and of stepwise change of substrate concentration of the feed medium as a disturbance were carried out. These results have proved that the above system successfully controls the glyceride composition of continuous interesterification reaction.View full abstractDownload PDF (1451K) -
Yue Liang, Masahiro Ohshima, Iori Hashimoto, Yukio Kohmura, Toshihiro ...1992 Volume 18 Issue 1 Pages 8-15
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThe plasticating extruder has a wide range of applications in the polymer processing industry. It is very important in stabilizing the extrusion rate to achieve high-quality products and high productivity.
In processing however, the extrusion rate cannot be measured on-line. To control the extrusion rate and to produce high-quality products, it is necessary to have an estimator, currently unavailable in the industry, which can predict the extrusion rate by secondary measured variables, such as the rotation speed of the screw, the temperature of the cylinder, or the pressure of the cylinder.
In this paper, we deal with the behavior of the extrusion rate and the problems concerned with building such an estimator. By applying the methods of multivariate statistical analysis and time series analysis to experimentally obtained data, relationships between the extrusion rate and the other variables of the extruder were made clear and a static/dynamic model for predicting the extrusion rate was developed. The estimator consists of two parts. The first is a steady element that can calculate the average extrusion rate ; the other is a dynamic element that can predict the dynamic behavior of the extrusion rate, which fluctuates around the value given by the steady element. Some simulations were performed to validate the estimator's predictability.View full abstractDownload PDF (1462K) -
Toshiyuki Yokota, Keiichi Suzuki1992 Volume 18 Issue 1 Pages 16-23
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSFreeze drying, which is an excellent build -up method for preparing fine ceramics powders, is not widely applied to industrial-scale production. One of the reasons is that the drying process takes much time to produce fine powders, and in some cases frozen solutions melt during the operation. In this study, some basic data of drying characteristics of frozen aqueous metal salt solutions in freeze-dry processing were obtained. Drying times were measured in a thermal balance unit. Various physicochemical factors such as qualities of salt, pH of the solutions and formation of cluster ions, and operational conditions such as freezing temperature, thermal energy feeding and operational pressure were related to the drying times. The results qualitatively showed that the drying time depends on the amount of unfreezable water solidified as non-crystalline state in a frozen solution, the water consisting of hydration water, and immovable water trapped in a concentrated amorphous solution.View full abstractDownload PDF (1568K) -
Yasushi Tomisaka, Yasuo Tanaka, Eiji Nakanishi1992 Volume 18 Issue 1 Pages 24-30
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSA new self-reflux and multiple-effect type of internal heat-integrated distillation system with a heat pump (SR-ME-HID) is proposed. This system is a combination of the self -reflux distillation system with a heat pump (SR-HID) and a modified multiple-effect distillation system well known as the Linde double column conventionally used for air separation at low temperatures.
A procedure is presented for determining the minimum reflux ratios and minimum flow rates of the heat pump for the SR-ME-HID. This provides the minimum reflux ratios and minimum flow rates of the heat pump for the present system as a function of the volatilities of the components contained in the feed, and compositions of feeds, distillate and residue.
Simulation results for the binary system of nitrogen and oxygen show that the present procedure provides reasonable minimum reflux ratios and minimum flow rates of the heat pump for a feed containing the light component at medium concentration. This suggests that the procedure presented is useful for design calculation of the present distillation system.
The energy required and that consumed are studied for the SR-HID and the SR-ME-HID. The results obtained show that the energy consumed in the SR-ME-HID is almost equal to that in the SR-HID for feed compositions lower than 80% of the light component.
However, the energy required in the SR-ME-HID is remarkably lower than that in the SR-HID for feed with the light component at high concentration. This suggests that the pressure in the distillate in the SR-HID is used effectively for separation in the SR-ME-HID.View full abstractDownload PDF (1220K) -
Takeshi Tomizawa, Yuko Nagakawa, Koji Arita1992 Volume 18 Issue 1 Pages 31-36
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSAdsorption equilibria of four halocarbons, dichlorodifluoromethane (CCl2F2, CFC-12), chlorodifluoromethane (CHClF2, HCFC-22), 1, 2-dichloro-1, 1, 2, 2-tetrafluoroethane (CClF2CClF2, CFC-114), and bromotrifluoromethane (CBrF3, halon-1301), on five activated carbons were measured at 316 K by the gravimetric method. The data obtained were correlated by use of the Dubinin-Astakhov equation (W= W0 exp {-(A / E) n}) with the parameters of the adsorbents. The exponent n ranged from 1.2 to 2.5, depending on the adsorbate-adsorbent system, though the limiting volumes of micropore adsorption space W0 of the adsorbent did not depend on the adsorbate. The characteristic energy of adsorption E and the exponent n were correlated by the molecular diameter d of the adsorbate.View full abstractDownload PDF (1107K) -
Demonstration of 30kWh-scale storage unitsYoshiyuki Abe, Yoshio Takahashi, Kotaro Tanaka, Katsuhiko Kanari, Ryuj ...1992 Volume 18 Issue 1 Pages 37-43
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThe present paper describes experimental results of the operation of 30kWh-scale molten salt latent thermal storage units using a eutectic of sodium hydroxide and sodium nitrate which is suitable for thermal storage around 250°C. The main problems of molten salt as a latent thermal storage material are its large volume change on phase change and its feasibility for use with structural materials. Using mild steel, two different U-tube storage units were built for testing heat transfer performance, structural feasibility and compatibility with the molten salt. From thorough and comprehensive material analyses after 1, 000 melting-freezing (charge-discharge) cycle tests, it was concluded that the present storage unit structure (horizontal U-tube and multiple-path type) and material selection were fairly feasible for a latent thermal storage unit with this particular molten salt.View full abstractDownload PDF (1413K) -
Akira Doi, Kazunari Nakao, Masaki Ikeuchi, Takashi Fujita1992 Volume 18 Issue 1 Pages 44-50
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThis paper examines theoretically and experimenally the maximum cooling capacity of a chemical heat pump that uses a reversible reaction of CaCl2/CH3NH2. The chemical heat pump consists of a reactor and a liquid vessel. CaCl2 is packed in the reactor and CH3NH2 is charged in the liquid vessel. This heat pump has two operating modes : regeneration mode and output mode. Each mode is operated for a fixed cycle period. The cooling output is supplied by the evaporation of CH3NH2.
A theoretical model that expresses cooling capacity through reaction rate constants, operating temperatures and cycle period is developed. It gives the relation between the cooling capacity and the cycle period. As a result, we find that the maximum cooling capacity is achieved at different cycle periods according to the operating temperature selected.
The experimental results were in good agreement with the theoretical analysis.View full abstractDownload PDF (1156K) -
Michio Yanadori, Masayoshi Hiramatsu, Toshio Inoue, Masanobu Hasatani, ...1992 Volume 18 Issue 1 Pages 51-57
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThis paper deals with a new heat exchanger incorporating a heater and a fluid way of heat medium for heat storage apparatus. It has the functions of supplying heat to heat storage material by the heater, discharging to heat medium and additional heating by heater through the same heat transfer surface. Such heat exchangers have been assembled into a reactor and a evaporator (condenser) of a prototype chemical heat storage apparatus. It has been confirmed that (1) the above-mentioned three operations can be performed, (2) steam generated in the reactor can be condensed in the condenser and (3) there exist differences in heat transfer characteristics between these results and previously reported results of an elementary experiment. Heat discharge experiments were conducted to check the temperature profile in each packed bed, calcium oxide or zeolite 4A in the reactor. It was found that high- and low-temperature portions are unevenly distributed in the zeolite packed bed. For the zeolite-water system, the effect of the initial temperature of zeolite and water on the temperature rise during adsorption was determined.View full abstractDownload PDF (1300K) -
Yoshihisa Mizuno, Keijiro Terashita, Yasushi Kondo, Kei Miyanami1992 Volume 18 Issue 1 Pages 58-65
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSA composite electrically conductive resin in which conductive fillers are kneaded within the matrix resin is gaining attention as an EMI shield material. Basic studies of the relation between the dispersion state of the fillers and kneading conditions or electrical conductivity are very important, but the studies to date are not sufficient.In this study, we performed continuous kneading of such conductive resins. Three resins, ABS, PS and PP, were employed as matrix resin. Bacause the electrical conductivity was affected by the state of construction of the electric circuit by the fillers, we took notice of the dispersion of fillers or their mean length.
The dispersion of fillers caused by kneading was evaluated by using a dimensionless number formed from the shear stress and the apparent viscosity of the matrix resin. We can quantitatively determine the dispersion state of fillers by using this dimensionless number. In addition, the relation between the conductivity and the kneading condition is also found by using the same dimensionless number, considering the dispersion state of the fillers and their length.
From this quantitative analysis, the relation between matrix resin, operating condition of continuous kneader and electrical conductivity can be clarified.View full abstractDownload PDF (1437K) -
Ryoichi Kuboi, Da-Ren Li, Yasushi Yamada, Isao Komasawa1992 Volume 18 Issue 1 Pages 66-71
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThe logarithmic partition coefficients, in a reverse micelle two-phase system, of several amino acids and di- and tripeptides at their pI were found to be linearly correlated with their hydrophobicities otherwise known. The slope of the line is considered to correspond to the relative hydrophobicity of the micro-water in the interior of the reverse micelle and bulk water, and is defined as the hydrophobic factor of the micelle, HFm. With anionic surfactant AOT micelles, progressive increase in salt addition results in smaller micelles and thus a lower molar ratio of water to AOT, Wo. A slight increase in the value of HFm is also observed. At high concentration of salt, that is, at very low Wo, the value of HFm increases appreciably, suggesting that much constructed periphery water may contribute most to the properties of the micro-water. The value of HFm is observed to vary from 0.18 mol/kJ at low salt concentration to 0.3 mol/kJ at high salt concentration.
The sensitivity of the partition behavior of amino acids and peptides at their pI to HFm depends on the hydrophobicities of the solute species. As Wo is varied from 18.0 to 4.9 by addition of Na2SO4, the partition coefficient of Trp-Phe increases from 200 to 1360, while that of Trp rises only from 12 to 20.View full abstractDownload PDF (970K) -
Ryoichi Kuboi, Yasushi Yamada, Isao Komasawa1992 Volume 18 Issue 1 Pages 72-77
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSHydrolysis of olive oil by Chromobacterium viscosum lipase in AOT reverse miceliar system was carried out, employing two methods of dissolving the lipase into micelles. Different trends were seen in the relation between the specific activity and the water content in the micelles.
In the case of an injection method, water content is controlled by the amount of water injected, which determines the micelle size and hydrophobicity without adding salt. The conformation of lipase was found to be varied reversibly by water content, corresponding to the activity change of the lipase. The activity reached maximum at a water content ([H2O] / [AOT]) of 7. In the case of the other technique, a phase transfer method, water content is determined by salt concentration in the aqueous phase in contact with micelles. The water content corresponding to maximum activity shifted to 12-13, below which the activity decreased drastically. The presence of a high concentration of salt may enhance hydrophobic interaction between lipase and AOT, resulting in an irreversible conformation change in the lipase. Addition of taurodeoxycholic acid to AOT micelles is likely to suppress the irreversible conformation change of the lipase and improve the activity at high salt concentration.View full abstractDownload PDF (943K) -
Results of numerical analysis of ball motionToyokazu Yokoyama, Hiroshi Usui, Genji Jimbo, Kishio Tamura1992 Volume 18 Issue 1 Pages 78-86
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThe effects of fractional ball filling on the behavior of balls and their collision characteristics in a vibration mill were investigated by image analysis with a video recorder as well as by a numerical calculation method called the “discrete block method”. It was made clear that an increase in fractional ball filling causes an increase in frequency but a decrease in average intensity of ball collisions, and that it results in acceleration of the circulation speed of the balls in the reverse direction to that of circular vibration of the mill.
A good correlation independent of vibration conditions and fractional ball filling was obtained between the rate constant of grinding determined by grinding experiments with glass beads as a feed material and the effective crushing collision frequency of balls calculated by the simulation and defined as the frequency of ball collisions whose intensity is greater than the strength of feed particles. From these results, it was made clear that there is an optimum fractional ball filling, depending on the strength of the feed materials and vibration conditions of the mill, that maximizes the rate of grinding.View full abstractDownload PDF (1463K) -
Takashi Hibiki, Manabu Yamaguchi, Takashi Katayama1992 Volume 18 Issue 1 Pages 87-93
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThe mechanism of transition from an undeveloped liquid jet, which is formed in the region between a single dripping and a laminar jet, to a laminar liquid jet in a gravitational and an electrical field is investigated by analysis of the energy of the jet. The liquid jet is modeled as a thermodynamically closed system and its energy is formulated. The most stable length of the jet is determined by the condition of the energy minimum. From calculation of the jet's energy it is shown that there are two troughs in the energy diagram. Therefore, the abrupt lengthening of the jet is caused by making the energy minimum with increasing the flow rate or the applied voltage. Transition from the energy trough of the undeveloped jet to that of the laminar jet then occurs.
The dependence of the critical voltage on the flow rate agrees well with the calculated line obtained from the energy equation.View full abstractDownload PDF (1077K) -
Shinichi Yuu, Eiichi Karube, Shoji Fujimoto1992 Volume 18 Issue 1 Pages 94-100
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSIt is important to predict the stress distribution in a powder bed for the design of storage vessels and unit operations with powder. Assuming a constant friction factor constant in the bed, we calculated the stress distributions in a storage vessel for various friction factors by using the incremental finite element method. The calculated results show that the stress distributions greatly depend upon the friction factor. However the friction factor in a powder bed varies with shear strain and packing ratio. In the present study we expressed the friction factors, which were obtained by a shearing tester, as a function of shear strain. Using them, we calculated the stress distributions and compared them with experimental results published in our previous paper. They are in fairly good agreement with each other in the horizontal stress distribution of the side wall as well as in the vertical stress of the bottom. Therefore, it would be possible to express the local changes of friction factors as a function of shear strain. Our calculated results also well describe the location of the arch at the side wall thus the results would be useful in designing powder storage vessels.View full abstractDownload PDF (1376K) -
Shinichi Yuu, Yoshio Kawaseki, Tsuyoshi Nagasue1992 Volume 18 Issue 1 Pages 101-107
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThe third-order upwind finite difference scheme is used for the convective terms in Navier Stokes equations to simulate directly the air free jet flow issuing from a round nozzle. The simulation was carried out for flow fields ranging from initial region to fully developed turbulent region. The kinetic energy conservation scheme is used for the convective terms. The mesh width is roughly seven times Kolmogorov microscale, but the calculated results of mean velocity distributions and turbulence characteristics (turbulent intensity distributions, Reynolds stress, power spectra, and velocity autocorrelations) fairly well represent the experimental data. The calculated power spectra of the turbulence intensity and the autocorrelations are also compared with experimental ones. The comparison shows fairly good agreement with experimental data for large-scale eddies of sizes larger than twice the mesh width. This indicates that the simulation well represents the motion of large-scale eddies which play an important role in a flow field formation, and suggests that neglecting the small-scale eddies in the third-order upwind finite difference scheme does not greatly affect the simulation of large-scale eddies.View full abstractDownload PDF (1262K) -
Keisuke Fukui1992 Volume 18 Issue 1 Pages 108-115
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThe process of forming longitudinal vortices in mixed free and forced laminar convection in a duct with aspect ratio 16 and consisting of horizontal parallel plates heated from below was studied by a flow visualization technique and numerical analysis. Thermal convection near the side-wall caused the first vortex. The second vortex was formed in the neighbourhood of the first one. With increasing distance from the entrance in the downstream direction, new vortices were formed toward to the center of the duct. There was a parameter Gr/Re2 for the flow similarity of development of such a 3-D flow structure. The effects of side-wall temperature on the generation mechanics of the first vortex near the side-wall were made clear.View full abstractDownload PDF (1402K) -
Keisuke Fukui, Satoshi Syoya, Tatsuo Kanki1992 Volume 18 Issue 1 Pages 116-121
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSIn the entrance region, stably and unstably stratified flows between horizontal heated plates are developed near the upper and lower plates respectively. In such a combined stably and unstably density-stratified turbulent flow the velocity and temperature were measured simultaneously to study the process of development of the combined-stratified turbulent flow. The effects of Gr number and Ri number on the development of these combined flows were investigated from measurements obtained under each of three thermal boun dary conditions. Different processes of development were observed for the buoyancy layers near the upper and lower plates respectively because of different stratification effects on the turbulent flow, so that the profiles of velocity, temperature, turbulent quantities and correlation of the fluctuations were observed. Counter-gradient momentum and heat transfers were found near the interface between stably and unstably stratified flows and also in the boundary layer of an unstably stratified flow. The degree of dissymetry of the profiles and counter-gradient transfer became greater as Gr number and Ri number increased.View full abstractDownload PDF (980K) -
Takayuki Takarada, Hideyasu Takezawa, Kotaro Tamura, Nobuyoshi Nakagaw ...1992 Volume 18 Issue 1 Pages 122-127
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSA Si wafer surface was treated in a fluidized bed of diamond particles and the treated Si wafer was used for the deposition of diamond. The effects of the treatment conditions on the particle deposition density were investigated. Diamond synthesis was carried out on the Si wafer surface by microwave plasma-enhanced chemical vapor deposition.
The fluidizing gas velocity and the treatment time were widely varied. Diamond particles of two size ranges (290-370μm and 88-115μm) were used. The particle deposition density of diamond was strongly dependent on fluidizing gas velocity, treatment time and diameter of fluidizing particles. The particle deposition density increased with fluidizing gas velocity and treatment time under the experimental conditions examined. A high particle deposition density of 7×107 l/mm2 was obtained by using diamond particles of 88-115μm as fluidizing particles under the treatment condition of fluidizing gas velocity of 37 cm/s and treatment time of 10h.View full abstractDownload PDF (890K) -
Atustshi Ikari, Yasuo Hatate, Ichiro Sunada1992 Volume 18 Issue 1 Pages 128-130
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSVapor-liquid equilibria of a slight amount of water in tetrahydrofuran were measured by use of an Othmer-type still in a dry box at atmospheric pressure. Those for a slight amount of water in dimethyl sulfoxide were measured by use of a Fowler-Norris-type still in the dry box at 4.67kPa.
The mean of the equilibrium ratio of the minor component (water) was 1.81±0.05 in tetrahydrofuran and 7.02±1.2 in dimethyl sulfoxide. The mean of the activity coefficient of the component was 7.02±0.23 in tetrahydrofuran and 0.386±0.061 in dimethyl sulfoxide.View full abstractDownload PDF (476K) -
Tomoaki Minowa, Tomoko Ogi, Yutaka Dote, Shin-ya Yokoyama1992 Volume 18 Issue 1 Pages 131-133
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThe effect of lignin content on the direct liquefaction of bark was examined. Six kinds of barks having different lignin content were liquefied by a steam explosion method and an autoclave method. With increasing lignin content, the oil yield decreased and the char yield increased. The oil yield by the steam explosion method was higher than that by the autoclave method and the char yield by the former was lower than that by the latter. Although lignin leads to the formation of char by condensation or repolymerization, the steam explosion would retard the reaction.View full abstractDownload PDF (625K) -
Hiroyuki Hatano, Ronghua Yang, Masaru Ishida1992 Volume 18 Issue 1 Pages 133-135
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSA single-layer gas-solid fluidized bed is developed by setting two glass plates vertically with a spacing space of which is slightly greater than the diameter of the particles. The behavior of gas bubbles is observed in detail by introducing high shutter-speed video cameras with 1/2000 s exposure time and an image analyzer.
It is found that the rising velocity of bubbles in the single-layer fluidized bed is almost the same as that in the ordinary two-dimensional fluidized bed. The effect of gas velocity and height from the distributor on bubble growth is almost the same as in the three-dimensional fluidized bed despite its extremely small bed width.View full abstractDownload PDF (404K) -
Motokazu Kikuchi, Tetsuo Miyamoto, Norikuni Yanagihara, Mikio Kanzaki, ...1992 Volume 18 Issue 1 Pages 136-138
Published: January 10, 1992
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThe kinetics of the whipping process was examined on the basis of the texture of whipped cream by use of a batch mixer. The degree of progress of whipping was represented by the firmness of the whipped cream as measured during the course of whipping under various conditions. The whipping rate was found to be expressed by an autocatalytic-type equation and the rate constant was expressed as the function of temperature and the rotational speed of the mixer.View full abstractDownload PDF (510K)
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