KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 17 , Issue 6
Showing 1-25 articles out of 25 articles from the selected issue
  • Michio Yanadori, Masanobu Hasatani, Hitoki Matsuda, Hironao Ogura, Mas ...
    1991 Volume 17 Issue 6 Pages 1067-1073
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    This paper describes a new heat exchanger incorporating an inside heater and a fluid way of heat medium in the heat storage container. The heat exchanger can transfer heat from the inside heater to the heat-storage material and from the heat-storage material to the heat-transfer medium in a fluid way. Also, the inside heater can directly heat the heat-transfer medium when the heat discharge rate from heat-storage material to heat-transfer medium decreases. An elementary experimental apparatus was made to establish the thermal design method for such a heat exchanger and heat-transfer experiments were conducted. It was found that the heat transfer rate in the fluid way is large, about 1.6 or 2 times the value calculated with the conventional equation for forced-convection heat transfer. Also, the present experimental data were correlated as a function of Reynolds number in the region of Reynolds number from 300 to 5000.
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  • Yoshiaki Sawada, Yoshiteru Kageyama, Masashi Iwata
    1991 Volume 17 Issue 6 Pages 1074-1079
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A new chemical process to prepare ultrafine iron particles by pyrolysis of iron pentacarbonyl, Fe (CO) 5, is developed. Fe (CO) 5 is a very attractive material for preparing ultrafine iron particles by the CVD process because it has a low boiling point of 103°C and the pyrolysis of Fe (CO) 5 can be carried out in the low-temperature zone below 100°C, even though it is a metallic organic compound. Fe (CO) 5 is charged into a reactor as gas phase with nitrogen and thermally decomposed in a magnetic field at a temperature in the range of 200-600°C. The size of the primary particle is 15-25nm and the shape of secondary particles is a necklace-like chain of 10-40 primary particles. The specific surface area is 30-50 m2· g-1. The particle is considered to have few pores in its surface layer because the specific surface mean diameter is very close to the average diameter obtained by TEM photograph. Coercivity of the iron powder generated by this process is 123-131 kA·m-1 and its specific saturation magnetization is 120-140 Am2· kg-1. This powder is expected to be applied as a highdensity magnetic recording medium.
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  • Akira Yamada, Katsuya Ebara, Sankichi Takahashi
    1991 Volume 17 Issue 6 Pages 1080-1087
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A low-temperature heat storage system based on differential aqueous solution concentration using a hydrophobic membrane is proposed. The hydrophobic membrane is used to concentrate and dilute a heat-storage medium.
    The optimum structure of the multilayered membrane module is obtained through experimental studies examining permeation characteristics of vapor. PTFE (polytetrafluoroethylene) is selected as the membrane material due to its hydrophobic character and relationship between opening ratio and pore size and thickness. Features of the pressure drop through the membrane module are studied under static process conditions wherein alternating operation of heat storage and heat release modes is performed, using experimental equipment, and variously shaped membrane modules are installed in a concentration and dilution vessel.
    The results are summarized as follows :
    (1) The pressure drop with low pressure vapor is exponentially reduced when the pore size is increased from 0.2μm to 3.0μm.
    (2) In the case of 3.0μm pore size, the pressure drop depends decisively on concentration and temperature polarization in solution passages, and on vapor flow in vapor passages.
    (3) The characteristics of permeation are correlated with vapor flux and pressure drop.
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  • Masaaki Sekino, Nobuya Fujiwara
    1991 Volume 17 Issue 6 Pages 1088-1095
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    This paper describes a precise analytical model of a hollow-fiber reverse-osmos is module and its verification by measured module performance data. This model's features are as follows :
    1) A, B values used in the model are derived from actual data at operating conditions under which there is no concentration polarization and from simulating the fiber bore-side pressure drop to be zero.
    2) Fiber bore-side pressure drop and shell-side pressure drop are both considered. Because of laminar flows the Poiseuille Eq. and Ergun Eq. are adopted respectively.
    3) Solution diffusion model and concentration polarization model are used as membrane transport equations.
    As result, the mass transfer correlation equation was obtained as
    Sh = 0.048 Re0.6SC1/3
    This equation is usable for both brackish water-type and seawater-type reverseosmosis modules.
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  • Yasuo Koseki, Sankichi Takahashi
    1991 Volume 17 Issue 6 Pages 1096-1103
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    To develop a high-solubility absorbent suitable for an absorption refrigerator, a mechanism of vapor pressure depression was proposed and experimentally studied on the basis of the “co-hydration” phenomenon.
    The solute in an aqueous electrolyte solution is ionized and has many water molecules (hydration). Hydration has two regions, a structure-making region (SMR) and a structure-breaking region (SBR). Water vapor pressure depression is related to the hydration number of both regions, while solubility elevation is related to the hydration number of the SMR.
    In the proposed vapor pressure depression mechanism, other ions are added to an aqueous solution to induce “co-hydration” in which part of the hydration molecules in the SMR move to the SBR. Then, as a hydration transfer region (HTR) in the SBR and a co-hydration region (CHR) in the SMR are formed, the vapor pressure depression is increased. The degree of vapor pressure depression is calculated by use of the equivalent hydration number of each region.
    This mechanism was examined experimentally using aqueous LiBr/CaCl2 solutions. Both experimental and calculated values gave a maximum degree of vapor pressure depression at a mixing ratio of [LiBr/ (CaCl2+LiBr) by mol] ranging from 0.2 to 0.6.
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  • Yasushige Mori, Shingo Hibin, Hideyuki Uemae, Masataka Tanigaki, Watar ...
    1991 Volume 17 Issue 6 Pages 1104-1109
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Continuous operation of the liquid surfactant membrane (LSM) process was tested for chromium (VI) recovery from a sulfuric acid solution using one-stage and threestage mixer-settler extractors. The organic (membrane) phase of LSM was kerosene with 12 vol. % 2-ethylhexyl alcohol and 2 vol. % polyamine (Exxon Chem., ECA4360J) without extractant.
    Chromium in the external aqueous phase was successfully transported and concentrated into the internal aqueous phase containing lithium hydroxide. It was found that multistage operation was effectively decreased the chromium concentration in the external aqueous phase, and that chromium concentration in the internal aqueous phase was further increased when half the emulsion flow from the settler was recycled to the same extractor. The experimental results of the continuous operation were found to be satisfactorily simulated by a model of the chromium transport with experimental parameters determined from batch experiments.
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  • Atsushi Suzuki, Tetsuo Fuchino, Masaaki Muraki, Toyohiko Hayakawa
    1991 Volume 17 Issue 6 Pages 1110-1116
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In the equipment layout of a multifloor batch plant, the determination of the floor for siting of each equipment nuit is an important problem because it must be solved before arranging the plot plans for each floor. The gravity flow of the piping should be satisfied during this determination. However, it is not easy to solve the problem for a multipurpose batch plant because gravity flows of all pipes cannot be satisfied.
    In this study, optimization of the gravity flow is converted into minimization of the pumping-up cost. Unification of the floor areas and preferable arrangement of equipment for operations (preference) should also be considered in the layout work, and it is natural to represent them as foundation and the penalty costs. Accordingly, this multiple-objective problem can be represented by a single-objective one. With directness, the present model contains constraints that change with conditions, but it can be transformed into a mixed-integer linear programming (MILP) model as a result of many considerations in the formulation. The floorfor siting of for each equipment unit is determined by solving this MILP model.
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  • Yoichiro Shimizu, Eiji Nakanishi
    1991 Volume 17 Issue 6 Pages 1117-1122
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    An adaptive observer was designed to estimate unknown parameters and unmeasurable state variable of a process. For good estimation, the design of a new adaptive observer, in which the number of parameters to be identified is reduced by taking notice of a priori information of the plant, was proposed. A control system with the adaptive observer was designed and its applicability to the adaptive control of CSTF was investigated. Simulation has confirmed that the adaptive observer can successfuly estimate unknown parameters and unmeasurable state variables. Also, the control system with adaptive observer can attain satisfactory control performance of CSTF with unknown parameters.
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  • Toshiro Murase, Chidphong Pradistsuwana, Eiji Iritani, Katsuhiro Kano
    1991 Volume 17 Issue 6 Pages 1123-1129
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The constant-pressure filtration characteristics in the crossflow microfiltration of dilute slurries are examined under various operating conditions, using a tubular ceramic membrane. On the basis of correlating a newly defined flux-controlling factor, a method for analysing both transient and steady filtration rates is studied.
    With a membrane having much smaller modal pores, much smaller than the size of the suspended solids, inspection of the crossflow filtration data points to a common feature : gradual reduction initially, followed by a substantially uniform value of filtration flux. The time dependence of the flux is represented by introducing a dynamic filtration coefficient, defined as the ratio of cake resistance in unstirred and stirred microfiltration, into the conventional Ruth filtration-rate equation. The dynamic filtration coefficient is related to a number of operational variables, in view of the fact that the final steady flux can be estimated as a power-law function of both the shear stress acting on the cake surface and the constant-pressure filtration coefficient.
    Positive agreement between calculations and experiments is confirmed for the filtration rate of slurries of polymethyl-methacrylate particles and baker's yeast.
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  • Rusli Amir, Tatsuya Sato, Hiroki Nagai, Kenya Saito, Kyoko Yamamoto, H ...
    1991 Volume 17 Issue 6 Pages 1130-1137
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The solid reactants in the UT-3 process must have high reactivity and durability. This report treats the preparation method and reactivity of the Fe-containing reactants.
    Reactant pellets were prepared by calcination of a pelletized mixture of magnetite powder, inert ceramic particles of silica and such additives as cellulose and graphite. It was shown that the pore volume of pellets increased linearly from 0.07 to 0.35 ml/g with the graphite content in the raw material mixtures, and that pellets prepared with 20 wt% graphite was five times as reactive as that prepared without graphite.
    As pretreatment reactions, bromination and hydrolysis were run to give the pellets high reactivity. A homogeneous reaction model was applied to the bromination and hydrolysis reactions. The reaction rate equations were determined for the two reactions of Fe compounds in the UT-3 cycle.
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  • Ning-He Wang, Koji Hattori, Shigeki Takishima, Hirokatsu Masuoka
    1991 Volume 17 Issue 6 Pages 1138-1145
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A new and rapid system was developed for measuring vapor-liquid equilibrium ratios of solutes at infinite dilution state (K - value) in a supercritical fluid + polymer system by combining vapor-liquid partition chromatography with a piezo - electric -quartz sorption method. The K-values for benzene and toluene in the CO2+ polyvinyl acetate system were measured by using the above system at 313.2 and 333.2K and up to 8 MPa. From the experiments it was found that each isotherm of the K- value has a minimum, and that two isotherms intersect at around 8 MPa. Further-more, the K - values were predicted by Sanchez and Lacombe's EOS with binary parameters evaluated by correlation of phase -equilibrium data for binary systems. Agreement between measured and predicted values was good.
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  • Hiroshi Sato, Takatoshi Miura, Takashi Arima
    1991 Volume 17 Issue 6 Pages 1146-1153
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Permeability in the blast furnace is maintained by lump coke, which has an average size of 5 cm and DI3015>90. Lnmp coke size is determined mainly by the growth of fissures from the wall side to the center of the coke oven, the formation behavior of which depends on the opereting conditions. In the formation process, microfissures are simultaneously formed in all directions and their formation behavior also influences the size of lump coke for the blast furnace. In this study we estimate the deformation behavior and thermal stress distribution of lump coke by assuming the size of lump coke formed in the coke oven and the conditions required for fissure propagation, considering radiative heat transfer within the fissure. The vertical tensile stress is estimated to reach about 10 to 20 MPa near the wall side. The fissure formation behavior regarding the growth of fissures arising from the wall side is successfully estimated. No longitudinal fissure formation is recognized, since only the compressive stress is predicted.
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  • Yoshinori Kutsuwa, Hisayoshi Matsuyama, Atsuo Kodama, Morimasa Ogawa
    1991 Volume 17 Issue 6 Pages 1154-1160
    Published: November 10, 1991
    Released: November 12, 2009
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    In the scheduling of operation of tanks for products storage, both the production plan and the delivery plan are always subject to change. Constraints and criteria for the schedules are also changed by revision of the structure of a system of storage tanks and the allocation of operators to tasks. In this paper a scheduling algorithm for storage tanks is proposed, taking account of two kinds of flexibility; the ability to cope with the changes in constraints and criteria, and the ability to make schedules so as to guarantee the feasibility of delivery at any time in the specified range. The effectiveness of the proposed algorithm is confirmed by developing a method to solve production planning problems including the scheduling of storage tanks and applying it to some example problems.
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  • Kenji Takahashi, Hirofumi Miyazaki, Shigeru Mori, Akira Tanimoto
    1991 Volume 17 Issue 6 Pages 1161-1167
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Time-averaged falling velocities of three sizes of spherical particles (d=8.0, 12.7, 15.9 mm) have been measured in vertically oscillating water. Drag coefficients were calculated, based both on a force balance equation of a free particle in an accelerating fluid and using a measured particle velocity. The calculated drag coefficient was predicted by a drag coefficient obtained from the 2/3-power law of energy dissipation. The experimental particle velocities were compared with the numerically calculated values, and agreement was within ±5% error.
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  • Hideaki Kurokawa, Toshio Sawa, Kenji Mitani
    1991 Volume 17 Issue 6 Pages 1168-1174
    Published: November 10, 1991
    Released: November 12, 2009
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    Heat and mass balance of direct-contact membrane distillation using PTFE porous membrane were studied using 1.0 wt % NaCl solution as feed liquid. Parameters such as temperatures and flow rates of feed and cooling water were varied and heat and mass transfer characteristics were studied by measuring the permeate rate and the heat transfer rate. It was found that in the membrane distillation system the permeate rate was proportional to the vapor pressure difference between feed and cooling water, but was influenced by membrane thickness, porosity and other variables. The heat loss by sensible heat transfer was reduced by operating at a high temperature level and a low temperature difference between feed and cooling water. The permeate rate and heat transfer rate were simulated by using a theoretical equation and experimental results of heat conductivity and membrane tortuosity.
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  • Hee Joon Kim, Yasuyuki Egashira, Hiroshi Komiyama
    1991 Volume 17 Issue 6 Pages 1175-1178
    Published: November 10, 1991
    Released: November 12, 2009
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    Characterization of growth species is a key issue in thin - film preparation processes like CVD (chemical vapor deposition). In this paper, a novel method to determine the surface reaction rate constant of growth species is proposed, consisting of experimental measurement of the growth rate profile on a micrometer-sized trench and theoretical analysis of the profile by a reaction and diffusion model.
    The method was successfully applied to an APCVD (atmospheric -pressure chemical vapor deposition) process to synthesize AlN from AlCl3 and NH3. An activation energy of 163 kJ/mol shows that the surface reaction rate constant was obtained in spite of the present condition of strong mass-transfer limitation of the overall growth rate by diffusion from the bulk stream to the growing surface.
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  • Tomoshige Nitta, Toshiya Tada, Yasuyuki Urata
    1991 Volume 17 Issue 6 Pages 1179-1186
    Published: November 10, 1991
    Released: November 12, 2009
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    Fractionation experiments were performed by a column elution method for styrene-maleic anhydride copolymer (weight-average molecular weight=4280). Mixed solvents of tetrahydrofuran (THF) and hexane were used, with stepwise changes in THF concentration. A silanized diatomaceous earth, Celite 545 (AW-DMCS), was good as a supporting material, both non-silanized Celite 545 and silica gel being inferior to the former due to either polymer adsorption or lack of inner surfaces to accommodate polymers. The distribution coefficients of polymers between solgel phases were measured for several mixtures of various THF concentration the coefficients were correlated against molecular weights by use of the separation factor σ. A simplified model of transfer of polymers from the inside of a supporting material to an eluent was proposed to simulate the polymer elution process, and numerical computations were performed. The model is capable of representing the molecular weight distributions of fractionated polymers fairly well by using experimental distribution coefficients and correlated mass transfer coefficients for polymers of different molecular weight.
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  • Hideto Yoshida, Touru Ninomiya, Hirohide Yamamoto
    1991 Volume 17 Issue 6 Pages 1187-1193
    Published: November 10, 1991
    Released: November 12, 2009
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    Experimental and theoretical studies were made on the deposition control of aerosol particles on a surface composed of different kinds of materials (copper-polyethylene and copper-nickel), coated with a polymer film.
    For a nickel-based plate with a polystyrene film coating, the electric potential on the film surface changed with film thickness. The experimental data agreed well with the calculated results, which applied Poisson's equation to the nickel-polystyrene region. The experimental results for the electric potential profile were nearly constantwhen the thickness of the polymer film was more than 20 and 40 μm for the copper-nickel and copper-polyethylene systems respectively. Because the contact potential difference of the copper -polyethylene system was higher than that of the coppernickel system, the thickness of polymer film to achieve a nearly constant electric potential profile was large in the case of the copper -polyethylene system.
    The particles charged with positive polarity deposited mainly on the polyethylene or the nickel surfaces, but the deposition flux can be controlled by the thickness of polymer film. It is also found that the experimental data of particle deposition agree well with the calculated results that take the measured electric potential profile into consideration as the boundary condition.
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  • Shuji Matsusaka, Teruo Aoyagi, Hiroaki Masuda
    1991 Volume 17 Issue 6 Pages 1194-1200
    Published: November 10, 1991
    Released: November 12, 2009
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    A new model has been developed to explain particle -reentrainment phenomena based on the adhesive -strength distribution of particles. Surface renewal of the powder layer and the time-dependent reentrainment rate are also included in the model. Experiments on particle reentrainment from a powder layer on an inside wall were carried out by use of a rectangular channel. Air velocity was controlled continuously, and currents generated by electrification of reentrained particles were recorded. Experimental study has shown that the adhesive strength is represented by a log-normal distribution. The mass of particles reentrained at a certain constant air velocity is well explained by the surface renewal model of the powder layer. It is also found that the reentrainment phenomena consist of two types of reentrainment, one with short time delay and the other with long time delay. Each of the reentrainment fluxes is approximated by a simple exponential function. The reentrainment model gives a good estimation for the unsteady reentrainment flux as a function of time under the effect of air acceleration.
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  • Hiroyo Matsumoto, Akira Kakimoto, Shuichi Sato
    1991 Volume 17 Issue 6 Pages 1201-1208
    Published: November 10, 1991
    Released: November 12, 2009
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    As a subsystem of a closed ecological life support system (CELSS), an artificial gill using a hydrophobic microporous hollow-fiber module was proposed. Dissolved oxygen and carbon dioxide can be exchanged between the aqueous phase in an algae cultivation tank and that in a fish habitation tank in opposite directions by contacting these two aqueous phases in the artificial gill. Two aqueous phases can be contacted as a liquid-gas membrane-liquid system in the present artificial gill, which allows simultaneous absorption and stripping of gases.
    In this system, mass transfer resistance through the microporous membrane can be ignored. The liquid-phase mass transfer coefficient inside the lumen kLi, could be correlated by an equation similar to the Sieder -Tate equation proposed for heat transfer, and the mass transfer coefficient on the shell side was about 70% of kLi.
    Also, a design method for the artificial gill is proposed on the basis of the data obtained.
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  • Kyoko Yamamoto, Hideo Kameyama
    1991 Volume 17 Issue 6 Pages 1209-1217
    Published: November 10, 1991
    Released: November 12, 2009
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    Kinetic studies of energy storage by ice production in polymer gel were made to show the practicality of the preriously proposed ice storage system. The rates of water evaporation from several kinds of gel were the same as that from pure water. The rate of water evaporation was linearly proportional to the difference between the water vapor pressure and the evacuation pressure, and inversely proportional to the square root of the evaporation temperature (Eq. (2)).
    The experiments were conducted under a rather high evacuation pressure of 98 to 99% of the vapor pressure at the vaporization temperature. The vaporization rate constant k 3 was 1g·pa-1·K0.5·min-1·m-2, and by use of a gel layer with the thickness of around 6 cm the rate was large enough to produce ice required for energy storage during 10 hr evacuation at night.
    The procedure of ice formation within the gel was studied by calculating the energy balance of the experimental system. The simulation was proved to be a useful method of elucidating the amount of ice produced in a gel when no other direct method can show the rate of frozen water to total water in the frozen gel.
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  • Akihiro Sakoguchi, Ryuichi Ueoka, Yasuo Kato, Yasuhiko Arai
    1991 Volume 17 Issue 6 Pages 1218-1221
    Published: November 10, 1991
    Released: November 12, 2009
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    The vapor pressures of pyridine, 4-methylpyridine, 4-ethylpyridine and 4-propylpyridine were measured by means of a flow apparatus in the temperature ranges of 283.68-322.46 K, 283.93-352.97 K, 284.49-352.80 K, and 294.05-374.05 K respectively. The observed vapor pressures of pyridine and alkylpyridines coincide with results calculated from the Antoine equation reported in the high-temperature range. The accuracy of each measurement in this work is estimated to be ±0.5 per cent. The data could be correlated within less than 1 percent absolute average deviation by the Abrams-Massaldi-Prausnitz (AMP) equation.
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  • Hiroshi Tsuchiya, Makoto Wakai
    1991 Volume 17 Issue 6 Pages 1222-1224
    Published: November 10, 1991
    Released: November 12, 2009
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    Solvolysis pulping, named for the method of extracting lignin from wood chips using a mixture of cresol and water has been studied as one of the organosolv pulping systems to separate the pulp. In this study, alkalis (NH3, NaOH) were added in the amount of 0.1-0.2 equivalent to that of cresol used in the cooking to evaluate the time dependences of the degree of delignification and decarbohydration. Both alkalis increased the reaction selectivity of delignification relative to degradation of carbohydrate because of reduced degradation of xylan component in wood.
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  • Motokazu Kikuchi, Norikuni Yanagihara, Tetsuo Miyamoto, Koji Inagaki, ...
    1991 Volume 17 Issue 6 Pages 1225-1229
    Published: November 10, 1991
    Released: November 12, 2009
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    In the design of a dasher for a continuous whipping machine, estimation of power consumption is necessary. It is not appropriate to treat the dasher as a conventional agitator because it has a very complicated structure and the viscosity of cream varies widely across the dasher. In this paper, the dasher structure is modeled by coaxial rotating cylinders and its torque is analyzed on the basis of the model for fluids of constant viscosity. The calculated torque showed good agreement with the experimental values.
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  • Eiichi Nishikawa, Yasumasa Shimada, Toshitaka Funazukuri, Noriaki Waka ...
    1991 Volume 17 Issue 6 Pages 1229-1231
    Published: November 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A pressure vessel loaded with GeO2 powder, platinum plate and water was heated under super/subcritical conditions of water. It was considered that GeO2 slightly dissolved in the water was decomposed into Ge and O2 on the platinum plate surface, and that reactions took place between Ge and Pt. Depending upon the density and temperature of the reaction environment, Pt3Ge and Pt2Ge compounds were formed on the platinum plate.
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