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Volume 7 (1981)
- Issue 6 Pages 545-
- Issue 5 Pages 435-
- Issue 4 Pages 327-
- Issue 3 Pages 215-
- Issue 2 Pages 109-
- Issue 1 Pages 1-
Predecessor
Volume 7, Issue 4
Displaying 1-18 of 18 articles from this issue
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Toku Nakayama, Ikuho Yamada1981 Volume 7 Issue 4 Pages 327-331
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSIn order to investigate the solubility characteristics and morphology of polyvinyl chloride resin, experimental studies using a standard microscope with a hot microstage were carried out and the following conclusions were reached : i) The resin particle made by two-step bulk polymerization dissolves into the plasticizer by breaking into secondary particles with increasing temperature, whereas the particle made by suspension polymerization does not break into secondary particles during the dissolving process. ii) The experimental results indicate that the core and skin model proposed by Chan et al. can also be applied to the dissolving process of polymer particles made by two-step bulk polymerization as well as particles made by emulsion polymerization.View full abstractDownload PDF (4683K) -
Naohiro Shiragami, Ichiro Inoue1981 Volume 7 Issue 4 Pages 332-334
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSA formula of the discharge coefficient of square bend flowmeter is obtained by experiments in the range of 3, 000 Re 18, 000, and this formula is compared with traditional theoretical formulae.
The pressure loss coefficients of bend and orifice flowmeters are compared, and it is found that the pressure loss of the bend flowmeter is smaller than that of orifice flowmeter for the range of experimental conditions employed.View full abstractDownload PDF (408K) -
Hitoki Matsuda, Ryou Nishio, Masanobu Hasatani1981 Volume 7 Issue 4 Pages 335-342
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThermal conductivities of organic materials like paraffin, polyethylene, polypropylene and naphthalene were measured in the course of melting and/or solidification by the combined method of a D.S.C. and a D.T.A. The melting and/or solidification processes of these organic materials were theoretically analyzed on the basis of thermal conductivity data thus measured, and the calculated rates were compared with the experimental data.
(i) It was found from the D.S.C. data that paraffin, polyethylene and polypropylene melted within a zone around a respective fixed melting temperature, with a constant width (zone-melting), independent of heating rates.
(ii) From the D.T.A. data, thermal conductivities of paraffin, polyethylene, polypropylene and naphtalene in the course of melting and/or solidification found to be almost constant and nearly to equal that of the liquid state for each material.
(iii) The theoretical results for melting rates of these materials coincided fairly well with the measured data, while for the solidification analysis, more precise examination on the crystal growth rate is likely to be needed.View full abstractDownload PDF (1386K) -
Hirotaka Konno, Tetsuya Kohya, Masayuki Toda, Takashi Saito, Masafumi ...1981 Volume 7 Issue 4 Pages 343-348
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThe heat transfer coefficients of a horizontal heated fine wire exposed to air were measured under corona discharge. The present results as well as the previous experiment indicated that Nusselt number, Nu, might be considered to be a function of Senftleben number, Se. But Nu number was affected by the gap H between needle electrodes and test section, the pitch p of the needle electrodes, the diameter of the test cylinder and other factors in the region of small Se number. Se number appeared to be introduced under the assumption of no corona wind. Thus no experimental equation could be obtained over the whole test range. Therefore, the corona wind was analyzed by the momentum equation under the assumption that the force acting on corona wind was electromotive force only. As a result, it is suggested that Nu number is a function of
d/μ√Icρ/Lb√H/p1-exp (-ψp/2H) / {1-exp (-ψp/H)} 1/2
All experimental data could be correlated by this parameter.View full abstractDownload PDF (936K) -
Hisashi Miyashita, Yutaka Shiorni, Kaichiro Wakabayashi1981 Volume 7 Issue 4 Pages 349-354
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSAn experimental investigation was performed to study the mechanism of augmentation of mass transfer on/near the transfer surface in a rectangular duct having a cylinder-type turbulence promoter, by using an electrochemical method.
The augmentative ratio of local mass transfer coefficients downstream from the promotor was measured by varying the clearances between promoter and wall. To examine the augmentative mechanism, wall shear stress, mass transfer intensity at the wall and turbulence intensity near the wall were measured corresponding to mass transfer profile. From the behavior of the profiles of each factor mentioned above, it was found that the augmentation of mass transfer depended on turbulence intensity near the wall surface in the case of no clearance, and depended not only on turbulence intensity but also on shear stress at the wall in the case of some clearance.View full abstractDownload PDF (998K) -
Katsumi Nakagawa, Yoshitaro Yamamoto1981 Volume 7 Issue 4 Pages 355-361
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSMass transfer from a single CO2 bubble rising in water was measured by using the impulse response method. The impulse response wave from a bubble was transferred from the time domain to the frequency domain by the fast Fouries transform and the natural frequency of that bubble was determined from the obtained power spectrum. The bubble equivalent diameter was obtained from its natural frequency. The mass transfer coefficient was computed by the variations of bubble volume with time. Experiments including 1, 230 runs were carried out by on-line processing over the bubble size range 0.308 to 0.623 cm, and a desk-top computer was used for controller and computing. Fast processing is an advantage of this procedure. That is, the required time from measuring to printing in this experiment was about 15 seconds per run. Mass transfer coefficients were treated statistically and the correlation between mass transfer coefficient and bubble equivalent diameter was well established.View full abstractDownload PDF (1305K) -
Masaaki Teramoto, Yoshikazu Miyake, Yoichiro Takenoshita, Minoru Kojim ...1981 Volume 7 Issue 4 Pages 362-366
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSAbsorption rate of NO in mixed solutions of FeIII-edta and Na2SO3 was measured using a stirred vessel with a flat gas-liquid interface at 298 K, and it was found that the absorption rate increases with tR, the time elapsed after the preparation of the absorbent. It was also found that FeII-edta is formed by the reduction of FeIII-edta with HSO3- (reaction (a)), and accumulates in the solution.
The effects of initial concentrations of FeIII-edta and Na2SO3, and tR on the absorption rate of NO are explained fairly well by assuming that NO reacts with FeII-edta according to (1, 1) - (1) order reversible reaction (b) rather than with FeIII-edta, and by using the rate equation obtained by the kinetic analysis of reaction (a) for estimation of the concentration of FeII-edta in the absorbent.
FeIII-edta HSO3-→FeII-edta (a)
FeII-edta+NO→←FeII-edta (NO) (b)View full abstractDownload PDF (724K) -
Koji Shimada, Hiroshi Hara, Tomoaki Sasaki, Noriaki Kaneki, Yoshiteru ...1981 Volume 7 Issue 4 Pages 367-371
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThe effects of operational conditions on the yields and composition of char, tar and gas produced during carbonization are discussed in a batch pressure fluidized bed.
The gas yield increases with increasing carbonization temperature and pressure in fluidized bed.
The gross heat value of product gas from carbonization using fluidizing gas with and without 20% H2, at 800°C under the pressure of 10 Kg/cm2. gage are 1.5 and 1.3 kcal/gr. Further addition of gross heat value using fluidizing gas with 20% H2 results in more CH4 and less CO2.View full abstractDownload PDF (778K) -
Haruhiko Ohya, Eiichi Kazama, Yoichi Negishi, Yoshimi Urayama, Hajime ...1981 Volume 7 Issue 4 Pages 372-376
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSReverse osmotic concentration of aqueous ethyl alcohol solution was carried out using cellulose acetate membrane (CA) and composite membranes (PEC). Separation of ethyl alcohol and flux through the membranes were measured under the following conditions : concentration of ethyl alcohol 2, 5, 10-15, 20-25 and 50 wt%, operating pressures 2, 4, 6 and 8 MPa. The most favorable separation obtained with CA membrane was 40% under 6 MPa with 2 wt % aqueous alcohol solution. PEC membrane separates alcohol over 90% at the same condition above and over 50% even with 20 wt% under 8 MPa. But the flux observed at the latter condition is less than 0.015 mol·m-2·s-1. Therefore, it may be feasible to concentrate up to 15 wt °o of alcohol with the PEC membrane. After 400 hours in operation with aqueous alcohol solution, CA membrane was seriously deteriorated but PEC membranes were not.View full abstractDownload PDF (804K) -
Naotsugu Ito, Kenzaburo Obata, Hiroshi Yoshitome1981 Volume 7 Issue 4 Pages 377-383
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThermal decomposition of solid is involved in almost thermochemical hydrogen production cycles. It is important to examine and analyze these decompositions because the design of more efficient reactors is required in terms of process heat efficiency. In this report the thermal decomposition of magnesium iodate Mg (IO3) 2 in the Mg-I cycle is studied.
Since this reaction takes place in two steps and is accompanied by large endothermic heat, a mathematical analysis with a single sphere is derived for heat transfer to the reaction surface in the unreacted core model. The result is that a decomposition scheme involving the two-interface model shows closer agreement with measurements.View full abstractDownload PDF (2946K) -
Junichi Kimura, Masanobu Hasatani1981 Volume 7 Issue 4 Pages 384-389
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSPrimary air entrainment for an atmospheric gas burner has been theoretically correlated with design and operation parameters, taking the temperature effect into consideration. The theoretical entrainment correlation has been compared with experimental data obtained from a fish-tail burner (in which errors in temperature measurement could be eliminated).
The results calculated from the correlation equation showed practically satisfactory agreement with the experiments, including the influences of gas-air mixture temperature, burner port area, gas density, gas flow rate and gas pressure.View full abstractDownload PDF (1065K) -
Kazuho Tamano1981 Volume 7 Issue 4 Pages 390-394
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSA new, simple method to measure diameters corresponding to the electric charge of liquid particles is proposed.
This principle of measurement is based on the fact that the electric current by charging corresponds to the electric capacitance of a conductive sphere such as a water droplet as decided by its diameter. The electric current required to electrify a droplet flows by contacting with an electrode kept at constant voltage. The droplet diameter is obtained from the peak value of electric current which corresponds to the amount of charge of the droplet.
The applicability of this method was verified by measuring diameters of metal spheres and water droplets of known size.
Furthermore, the size distribution of water spray produced by a pressure nozzle, measured using this method, was compared with the result obtained by the usual oil film method.
As the result of experiment for water droplet, it was confirmed that this method is usable for size measurement of water particles larger than 18 μm in diameter.View full abstractDownload PDF (4605K) -
Yoshihisa Kato, Kazuo Hashii, Kazuo Saito, Kinnosuke Watanabe1981 Volume 7 Issue 4 Pages 395-401
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSWe studied the design and testing of a high-pressure powder feeding apparatus used in some process to feed powder material, such as burnt lime, or metallic compounds in oxygen atmospheres in expected accuracy, and also to examine the repeatability of powder feeding and to study the safety against ignition or explosion based on impurities contained in the powder, such as a small amount of metallic iron powder due to use of a high-pressure oxygen as carrier gas for the powder.
It was understood that the accuracy of the powder feed rate was within a range of ±3 wt%, and gas flow rate did not affect the powder feed rate accuracy.
Further, by mixing an iron powder ranging up to 200 mesh as impurity in the burnt lime, it was found that the temperature at the surface of the transfer tube was raised by friction of the mixed powder against the wall, and we calculated the energy required to cause ignition of the iron powder as impurity.
As a result, the condition under which the mixture of powder and impurities (iron powder) was safely transferred by high-pressure oxygen gas was found to be a mixing ratio of less than 0.1 wt% and a carrier gas speed of less than 15 m/s.View full abstractDownload PDF (2790K) -
Takeshi Takahashi, Akira Kanagawa, Naoyuki Ueda1981 Volume 7 Issue 4 Pages 402-407
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSAn aerosol particle visualization device based on the ultramicroscope technique was constructed for measuring particle charges. The charges on monodisperse polystyrene latex particles produced by atomization and evaporation of a suspension were determined from measurements of electric mobility.
The charge distributions were approximately symmetric with respect to polarity and some particles carried over 1, 000 electron units of charge. The average absolute charges of the polystyrene latex particles increased with increasing latex particle size and exceeded the average charge of droplets produced by atomization of the suspensions.
The charges on the polystyrene latex particles were neutralized by electrostatic deposition of the charged stabilizer particles resulting from evaporation of droplets containing no poly-styrene latex particles.View full abstractDownload PDF (1212K) -
Mompei Shirato, Toshiro Murase, Hidetosh Mori1981 Volume 7 Issue 4 Pages 408-414
Published: July 10, 1981
Released on J-STAGE: February 19, 2010
JOURNAL FREE ACCESSTo obtain a method for analyzing the internal dehydration mechanism of granular beds in centrifugal fields, the beds are visualized as a collection of capillary tubes of various radii, and the previous flow equations for the capillaries in gravitational drainage are modified in view of the existence of centrifugal force. An analytical method for calculating both the moisture distribution under centrifugal drainage and the final equilibrium moisture distribution in beds is presented. A simplified equation for predicting average saturation Sav vs. time θ is also derived in consideration of the effects on deliquoring rates due to the movement of a filmwise liquid. It is shown that the time changes in the moisture distribution and the average moisture content of the bed under centrifugal drainage are easily evaluated from calculation based on the final moisture distribution curve of the bed drained by gravity.
Satisfactory agreement between calculations and experiments are confirmed for centrifugal drainage of particulate beds of glass beads and Soma sand, under the conditions where the initial centrifugal effect Zav⋅0 ranges from 9.3 to 87.7.View full abstractDownload PDF (1359K) -
Satoshi Nakajima, Norihiro Takama, Katsuo Shiroko, Tornio Umeda1981 Volume 7 Issue 4 Pages 415-421
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSThis paper presents a method to solve the design problem of a heat exchange system which consists of furnace, product coolers, raw material preheaters and other heat exchangers from the view-point of a multi-objective optimization. The minimum approach temperature and the system structure of the heat exchange system are determined on the heat availability diagram constructed by plotting Carnot efficiency against heat load by simultaneously evaluating investment cost, running cost and complexity of system structure. As an illustrative example, a heat exchange system that pre-heats crude oil by some distillates and pumparounds in a crude distillation system is taken to show the practical usefulness of the present method.View full abstractDownload PDF (1152K) -
Shinichiro Yokoyama, Toyohiko Hayakawa1981 Volume 7 Issue 4 Pages 422-428
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSSafety management, considering both early detection and prevention of equipment failures, is necessary for prevention of disaster in the chemical plant.
The purpose of this study is to propose a scheduling method of mechanical fault diagnosis involving a diagnosis model. Prevention of failure of important equipment by observation of failure symptoms extends the life of the equipment, and thus the life of the plant is extended.
Symptoms such as malfunction, a partial defect and many other small failures appear before a catastrophic failure and destruction of the equipment occurs.
In this study, a two-stage failure model, involving probability density function (p.d.f.) of the occurrence of these symptoms and p.d.f. of the occurrence of a catastrophic failure after that, is assumed.
In a numerical example, 2-parameter gamma distribution failure models having different shape parameters from each other on two stages are treated for one component, and series system of five components. Useful methods of optimizing the maintenance schedule and minimizing the cost per unit time are shown under the criterion of required system reliability.View full abstractDownload PDF (1358K) -
Noriaki Kaneki, Hiroshi Hara, Kazuaki Tokuhashi, Yoshimitsu Jomoto, Ka ...1981 Volume 7 Issue 4 Pages 429-433
Published: July 10, 1981
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSDownload PDF (807K)
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