Journal of the Society of Materials Science, Japan
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
Volume 27 , Issue 298
Showing 1-21 articles out of 21 articles from the selected issue
  • Michio INAGAKI, Shigeharu NAKA
    1978 Volume 27 Issue 298 Pages 604-609
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
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  • Hisakazu SUNADA, Akinobu OTSUKA, Yoshiaki KAWASHIMA, Hideo TAKENAKA
    1978 Volume 27 Issue 298 Pages 610-613
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The process of agglomeration of powder particles has been simulated on a digital computer by using a two dimensional model based on the geometrical model of floc formation proposed by Sutherland. The concept of coagulation probability upon collision between particles and the factor of time-course of floc formation were newly introduced to obtain a number of floc having various size distributions.
    At the beginning 100 discs of equal size numbered from 1 to 100 were arranged as the unit particles. Two discs were chosen randomly and collided each other. Whether the collided discs coagulated or not was determined by comparing the pseudo-random number generated at every collision with the coagulation probability P; P=2/(Dsn+1) where Ds is the size of a smaller colliding particle and n is a constant. The resulting agglomerate was replaced to one of the two colliding particles and, therefore, the total number of particles remained 100 throughout the computation. The stirring time in the coagulation process was described by the number of collision, i.e., the number of the generation of pseudo-random number.
    The average floc size increased with time until an equilibrium state was reached, and the process obeyed the first-order kinetics.
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  • Yoshiaki KAWASHIMA, Hideo TAKENAKA, Hisakazu SUNADA, Akinobu OTSUKA
    1978 Volume 27 Issue 298 Pages 614-617
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Monte Carlo simulation of agglomeration in liquid suspension in a double cylindrical agglomerator was made by a random walk model. When the clearance between the inner and the outer cylinder is assumed to be infinitesimal, the agglomeration process in this agglomerator could be replaced with the collision and the coalescence phenomena of particles on a two dimensional plane. Initially, arbitrary numbers of spherical-particles whose diameter was unit, were randomly dispersed on the plane. Subsequently, the particles were mixed on the plane resulting in the collisions of particles. The moving direction of each particle was determined by two random numbers generated by a computer. Collided particles were coalesced to make up an agglomerate when the generated random number was less than the probability coefficient of coalescence (P). When this probability coefficient was set constant during the agglomeration process and was independent of the diameter of collided particles, the agglomeration kinetics was represented as the second order rate process. While the probability coefficient was represented as a function of the diameter of collided particles, P=1/(DiDj), the agglomeration process at the initial stage, traced the second order process under the condition of P=1.0, and was followed later with the slow rate process which might be controlled by a layering mechanism.
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  • Kaoru UMEYA, Ryuichi HARA, Takao INOUE
    1978 Volume 27 Issue 298 Pages 618-622
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Powdered polystyrene was compacted into the specimens having various void fractions at 100°C. In order to compare with these compaction-molded specimens, injection-molded specimens having no void were prepared too. The rheological characteristics of these specimens were examined by the vibration test method, that is, the temperature dependences of dynamic storage modulus E' and dynamic loss modulus E" were investigated. The results obtained were summarized as follows:
    (1) The value of E' was found to increase with decreasing void fraction at various temperatures, which was mainly attributable to the effect of void volume.
    (2) Glass transition temperature Tg, which corresponded with the temperature where the value of E" took the maximum, was found to rise with decreasing void fraction.
    (3) The values of E' and Tg of the compaction-molded specimens having the least void fraction were different from those of the injection-molded specimens, because both differed in the history of heat and strain.
    (4) From the results of temperature and frequency dependences of E" at 95∼100°C, the relaxation mechanism of polystyrene powder compact was presumed not only to be dominated by the response of polymer segments but also to be influenced by the macroscopic mechanism due to the unstematic strain recovery of predeformed particles.
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  • Mitsuo KAMIWANO, Katsuyuki SAKAMOTO, Toshimichi KOGA, Ryuichi AOKI
    1978 Volume 27 Issue 298 Pages 623-627
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    An attempt has been made to employ a linear photo-diode array (so-called an image sensor), such as the one used as the image pick up element in picture analysis or facsimile telegraphy, for simultaneous determination of the diameter and velocity of moving solid particles.
    An optical microscope was used in this study. Transparent glass spheres having 120∼310 micron diameter were placed in rows on the movable stage of the microscope, which was moved at a constants speed. The images of moving glass spheres were detected with an image sensor attached on the top of microscope. After A-D conversion of the output signals of the sensor, they were fed into a miniature computer, where each particle diameter and velocity were calculated.
    The results showed the possibility of making general use of image sensors for accurate measurements of the size and velocity of solid particles in motion.
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  • Ayao TAKASAKA, Minoru SATO, Takashi OKUYAMA, Yoshihiro MATSUDA
    1978 Volume 27 Issue 298 Pages 628-631
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The adsorption of H+, NH4+, Cu2+ and Cd2+ on Itaya-zeolite consisting mainly of clinoptilolite was investigated.
    The adsorption isotherms were found to be approximately expressed by the Freundlich equation. The order of adsorption selectivity was NH4+>H+>Cu2+>Cd2+
    As Itaya-zeolite has excellent adsorption capacity comparable to synthetic zeolite (MS 5A) or active carbon, it seems that a fixed bed of Itaya-zeolite is applicable for removal of cations from waste water.
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  • Yoko SUYAMA, Akio KATO
    1978 Volume 27 Issue 298 Pages 632-637
    Published: July 15, 1978
    Released: June 03, 2009
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    The effects of various additives on the anatase-rutile transition reported by various investigators and the present authors were summarized and the mechanism of the action of additives was discussed.
    For the transition, although most of the additives exhibit accelerating effect, several additives such as SiO2, H3PO4, Na2SO4, and some chlorides exhibit remarkable inhibitory effect.
    These accelerating and inhibitory effects could reasonably be explained by considering the following three mechanisms of the action of additives on the rutile nucleation at the surface of TiO2:
    (1) The inhibitory effect caused by the prevention of mutual contact of TiO2 particles, (2) the accelerating effect caused by structural defects induced on the surface of TiO2 by a reaction between the additive and TiO2, and (3) the inhibitory effect caused by a film of a stable Ti-compound phase formed on the surface of TiO2. The first effect becomes important at low temperatures.
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  • Fujio KANEKO, Manabu TAKEUCHI, Hideo NAGASAKA
    1978 Volume 27 Issue 298 Pages 638-642
    Published: July 15, 1978
    Released: June 03, 2009
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    The composite powders of metal oxides and MMA polymer were prepared by adding H2SO3 solution to mixed suspension of MMA monomer, metal oxide powders and water. Powders of different size and shape were obtained according to the reaction conditions and the natures of oxides. The properties of these powders were studied by microscopic observation, thermal analysis and measurements of corona charging properties.
    The polymer contents in these powders are found to be affected by the natures of the oxides, reaction temperature and quantity of H2SO3 solution. The corona charging properties of composite powders depend on the natures of oxide and reaction conditions, but no clear relation between the polymer content and these charging properties is found. The charging value of Fe2O3 composite powder is larger than that of MMA powder and the decay of charge is slow. On the other hand, the charging value of ZnO composite powder shows the medium value and the decay of charge is rapid.
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  • Sohachiro HAYAKAWA, Satoru YAZAWA, Katsuhiko ABE, Shigeru FUYUKI
    1978 Volume 27 Issue 298 Pages 643-646
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Incidence of UV or visible light on ZnO powder in O2 atmosphere of low pressure either enhances or reduces the adsorption of O2. The phenomenon depends quantitatively upon the history of sample powders as well as the measuring conditions such as wavelength, intensity of exciting light, temperature, atmospheric pressure and so on.
    Three types of powders showing the positive effect (photoadsorption), negative effect (photodesorption) and almost no effect were prepared. The detailed measurements were carried out at various conditions on the powders of photoadsorption type, and the following conclusions were derived; (1) the spectral response showed the fundamental absorption to induce the phenomenon and (2) the relative photoadsorption rate was proportional to the atmospheric pressure and also to the root of light intensity. A mechanism was proposed to the photo-effect on O2 adsorption.
    The photoadsorption of H2 on ZnO powder was very slight compared to that of O2. The pressure changes by incidence of light for H2 and O2 were enough to separate each other. Thus the separation between H2 and O2 was found to be possible by the use of ZnO powder and solar light.
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  • Hiroshi UTSUGI
    1978 Volume 27 Issue 298 Pages 647-652
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The silica gels were chemically treated with several kinds of alcohol or with tartaric acid dibutyl ester. Most of the surface silanols on these silica gels were confirmed to be substituted by the corresponding alcoxy group of the alcohol used or by tartaric acid diester group by means of their ir-spectra and the number of surface group estimated from the results of the microanalysis. Both original and surface-treated silica gels were used as the supports to investigate the gas chromatograph. The solutes used were the isomer of dimethyl cyclohexane, the mixture of n-heptane, n-hexene and benzene and the mixture of cyclohexane, cyclohexane and benzene. The following results were obtained:
    (1) The gas chromatograph using the original silica gels showed an appreciable tail in the shape of peak and a long retention time. These were attributed to the strong interaction between the surface silanols and solutes.
    (2) The gas chromatograph using the silica gels treated with linear chain alcohols showed that the longer carbon chain (increasing hydrophobic nature) causes more effective separation of the solutes mixture and symmetric shape of the peak. These were attributed to the low energy surface of these supports.
    (3) The silica gels with the surface group containing the hydrophilic functional groups such as _??_C=O and _??_C=O-O- dispersed well into water, and showed hydrophilic nature. However, in the gas chromatograph of the mixture of the non-polar solutes these supports behaved like the ones with low energy surface (symmetric peak shape and the short retention time.). The heat of adsorption obtained from the plots of logtR/T against 1/T supported these results.
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  • Osamu OHODAIRA, Megumi ISEKI
    1978 Volume 27 Issue 298 Pages 653-657
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The maximum amounts of liquid imbibed in colloidal silica, perlite and diatomaceous earth at their pendular stage were determined graphically from the variations of the agglomerate diameter and residual specific pore volume of each mixture with the amount of the liquids added.
    The ratio of the amount of liquid imbibed at the powder limit (the end of its pendular stage) to that measured by the rub-out method (JIS K5101-1964) for the colloidal silica was found to be much larger than those for the perlite and the diatomaceous earth tested.
    The total specific pore volume of each colloidal silica showed an inherent value irrespective of the kind of liquid at the powder limit, although the values of the agglomerate diameter and residual specific pore volume were different.
    These findings are useful in the utilization of colloidal silica for making powders mixtures from liquid drugs.
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  • Makoto HAYAMI, Masunori SUGIMOTO
    1978 Volume 27 Issue 298 Pages 658-662
    Published: July 15, 1978
    Released: June 03, 2009
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    In order to study the draining of water from a vessel by means of capillary rise, experiments were carried out by using two kinds of capillary bundles. One was a packed column of glass beads or silica sands. The other was a bundle of cotton fibers (sterilized gauze) having no column wall.
    It was obtained experimentally that the rate of draining Q by capillary flow was given as follows:
    (1) In a packed column with a glass wall, Q can be calculated by Kozeny-Carman's Eq. (2) in HX<hd.
    (2) In a bundle of gauze without a column wall, Q is proportional to the head difference Δh and inversely proportional to L', which is the length of a bundle exposed to the air. This is because the draining through the bundle depends on the water surface.
    (3) In both cases, Q decreases with increasing the height of capillaries HX except the lower HX, due to the decrease of water saturation in the bundles by capillary rise.
    As a result, it is suggested that it is possible to drain a supernatant liquid during settling in a sedimentation tank by means of capillary flow in the bundle without a column wall.
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  • Yoshiteru KANDA, Hiroshi GUNJI, Hirosuke TAKEUCHI, Kiyohiko SASAKI
    1978 Volume 27 Issue 298 Pages 663-666
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    To investigate ball mill grinding from the kinetic point of view, the effects of hardness of samples, feed weight and feed size on the grinding rate constant of weight fraction decrease of feed have been studied.
    The samples used were silica glass, borosilicate glass, quartz, feldspar, limestone, marble and talc. The pebble mill consisted of a 12.8cm-diameter by 13.2cm-long cylinder and the grinding medium was 40 balls of 3cm diameter having the total weight of 1180g. In the case of wet grinding, 400cc-water was added to the mill. The test were done at the speed of 88.1% of critical one. The experiments were performed on 10 different particle sizes from 4 to 100 mesh for dry grinding and on 8 different ones from 8 to 100 mesh for wet grinding to obtain the grinding rate constants. The following results were obtained.
    Dry; K1=0.02HV-0.23·(WS/WB)-1.5·(xf/x0)
    Wet; K1=0.06HV-0.23·(WS/WB)-1·(xf/x0)0.7
    where K1 is the first order decreasing rate constant of weight fraction of feed, HV the dimensionless Vickers hardness, WS the feed weight, WB the ball weight, xf the feed size and x0 the optimum feed size.
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  • Yoshiteru KANDA, Yasushi ABE, Michitaka SUZUKI, Takashi ABE
    1978 Volume 27 Issue 298 Pages 667-670
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    In the previous paper, the authors studied the effects of hardness of samples and feed weight on grinding rate constants from the kinetic point of view. In the present paper, we studied the effect of feed size on the rate constants of weight fraction decrease of feed and specific surface increase.
    The samples used were silica glass, borosilicate glass, soda glass, quartz, feldspar, limestone, gypsum and talc. The pebble mill consisted of a 12.8cm-diameter by 13.2cm-long cylinder and 40 balls of 3cm diameter having the total weight of 1180g. The testes were done at the speed of 88.1% of critical one with several feed size ranges, 14∼20, 20∼28, 28∼35, 35∼48, 48∼65, 65∼100, 100∼150, 150∼200mesh. With an assumption that the shape factor was six, the specific surface of fine particles was measured by the permeability method and that of coarse ones was calculated from the size distribution. As the result, the following equations were obtained.
    K1=0.02HV-0.23(WS/WB)-1.5(xf/x0)
    KS=0.41HV-0.58(WS/WB)-1.5(xf/x0)
    Where K1 is the first order decreasing rate constant of weight fraction of feed, HV the dimensionless Vickers hardness, WS the feed weight, WB the ball weight, xf the feed size, x0 the optimum feed size and KS the zero order increasing rate constant of specific surface. To obtain KS from K1, the following equation was derived.
    KS=20HV-0.35K1
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  • Syoichi MOROHASHI, Masataka NOMURA, Yasushi SAWAHATA
    1978 Volume 27 Issue 298 Pages 671-675
    Published: July 15, 1978
    Released: June 03, 2009
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    An experimental study on the effect of surface roughness on the formation of ultra fine powders was carried out by a rotating friction mill devised to produce submicron powders by mutual friction grinding of two specimens of marble. The following results were obtained.
    (1) The surface roughness of the specimen decreased with particle size of carborundums used for final finish of the specimen surface. The specimen surface changed to take a different roughness or undulation just after abrasion, but it reached a constant roughness or undulation as the abrasion approached to a steady state.
    (2) By scanning electron microscopy, it was observed that the specimen surface seemed to be melting and the surface layer changed to an amorphous state from a crystalline pre-abrasion state. From the electron diffraction pattern, the similar result was obtained on the surface layer of the produced powder.
    (3) The particle size of the produced powder decreased with the surface roughness of specimen. The reason is considered that the cohesion area is smaller when the surface roughness is smaller.
    (4) The mass of the produced powder increased as the surface roughness decreased. This tendency arises from the fact that the number of contact point and contact area of the tiny surface protuberance is closely related with surface roughness. It is concluded that the surface roughness of the specimen is an extremely important factor in mutual friction grinding.
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  • Yuhbun TSUTSUMI, Kenzo OHKUSHI
    1978 Volume 27 Issue 298 Pages 676-680
    Published: July 15, 1978
    Released: June 03, 2009
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    The effect of vibrational force on the granulation of powdered materials flowing down on a chute has been studied. Powder of size under 210μ was fed and flowed down continuously on a vibrated, inclined chute of 340mm long and 75mm wide, and a binder solution was sprayed over the vibrating bed so as to cause granulation. The variables investigated were the inclination of the chute, the direction, the amplitude (a) and frequency (n) of the vibration, and the material of the chute, by using several kinds of powdered material.
    The size distribution of granules obtained showed in general the Rosin-Rammler distribution by mass. For all kinds of powder, the mass mean diameter (d) of the granules formed was found to be given by:
    d=a{α+(βn)2}2GV-3/2
    where GV is the ratio of the vertical component of the maximum vibrational acceleration to the gravitational acceleration, and α and β are constants depending on both the particulated material and the granulating operation.
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  • Terutoshi MURAKAMI, Muneharu ISHIKAWA, Masao SHIROUZU, Tatsuo SHIROKAN ...
    1978 Volume 27 Issue 298 Pages 681-685
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    For measuring the size and velocity of fine particles the double pulsed laser holographic method is a useful technique, but this is not convenient for the system of high particle number density, because of the difficulty in identification of moving particles on a double exposure hologram. In order to remove this difficulty, we have developed a new technique employing the two pulsed lasers of different wave length.
    The two lasers are set in the same optical axis passing through the observation section, and fired at an interval of few milli∼micro seconds depending on the particle velocity in the experimental objects. The two output beams with holographic information of the object particles are separated into two camera boxes by a half mirror and two interference filters, and then the holograms of the particle system at different instants are recorded on two films separately. These two holograms are superimposed each other, and the distances of particle movements are measured microscopically. From the distance and pulse interval, the velocity distribution of particles are obtained. This new technique was applied successfully to observe the disintegration mechanism of liquid spray.
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  • Manabu TAKEUCHI, Kazuo MIWADA, Hideo NAGASAKA, Sohachiro HAYAKAWA
    1978 Volume 27 Issue 298 Pages 686-690
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The motion of carbon powder in a vibrating vessel has been investigated by measuring electrical conduction through the powder bed. The carbon powder used in this study consisted of spherical particles with the diameter of 80∼180μm and with the bulk density of 0.9g/cm3. The sample powder was packed into an acrylic vessel equipped with nine pairs of electrodes. The vessel was oscillated vertically by a vibrator and the electric current flowing horizontally through the powder bed was measured. Both the effective current and the cyclic shape of the current varied with the frequency and the maximum acceleration of oscillation. When the maximum acceleration was less than 1g, the duration in which the current was off, was not found in a period of oscillation. On the other hand, when the maximum acceleration was increased beyond about 1g, the duration in which the current was off, appeared. This is attributed to the appearance of the duration in which the particles fall freely without exertion of forces on each other. An exceptionally steep decrease in the effective current was found when the maximum acceleration exceeded about 1g. The critical acceleration which caused the steep decrease in the effective current became greater as the location of electrode was lowered. This is due mainly to the frictional forces between particles. The shape of current associated with the oscillation of powder bed was sinusoidal up to the maximum acceleration of about 1g and deviated from the curve beyond 1g. The phase lag in the oscillation of current against that of the vessel was also measured. The resonance phenomena between the frequency of oscillation and that of the alternating electric field applied to the electrodes were observed.
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  • Jusuke HIDAKA, Shigeo MIWA
    1978 Volume 27 Issue 298 Pages 691-695
    Published: July 15, 1978
    Released: June 03, 2009
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    A sonic oscillating air column method of sieving and its applicability for fine powders are discribed. The phrase“Oscillating air column”refers to a confined body of air moving essentially in a vertical direction.
    Although the operating frequency of 50 or 60Hz are being used to sieve coaser particles, a lower frequency (about 20Hz) is adequate to sieve fine powders. This optimum frequency is almost independent of sound pressure, which makes the sieving rate increase. A sound wave radiated to the sieve is affected by the rubber menbrane used to achieve a dust-tight for sound source.
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  • Misao NISHINO, Masafumi ARAKAWA
    1978 Volume 27 Issue 298 Pages 696-700
    Published: July 15, 1978
    Released: June 03, 2009
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    The particulate film method was investigated for practical particle size measurement. Water filled in a trough was circulated by a pump. Powder was spread on a trembling water surface and was compressed to form a monoparticulate film. The mean particle size perpendicular to the water surface can be determined by measuring the area and packing fraction of the particulate film. The packing fraction here was measured actually from the area occupied by particles in a photomicrograph of the particulate film. Powders of Glass beads, Calcium carbonate, Lycopodium and Mica were first treated with a flotation agent and then were used as the samples. The results agreed well with the particle size measured by the microscopic method. The packing fraction was found about 0.9 in most cases. Thus the packing fraction may be fixed practically at the value of 0.9 and the mean particle size can be determined only from an area of the particulate film.
    As a conclusion, the particulate film method was found to provide simple and practical measurement of the particle dimension, especially such as the thickness of thin flake-like materials and the specific surface area of large particles.
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  • Hiromichi MURAKAMI
    1978 Volume 27 Issue 298 Pages 701-706
    Published: July 15, 1978
    Released: June 03, 2009
    JOURNALS FREE ACCESS
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