Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
24 巻, 262 号

• 粒子の微細構造から粒子の極限へ
水渡 英二
1975 年 24 巻 262 号 p. 588-594
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
• 中野 産治, 遠藤 外雄
1975 年 24 巻 262 号 p. 595-599
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
A minimum circle circumscribing the projection of a particle is devided into four parts by defining the circumcenter to the origin of a Cartesian coordinate system.
The shape index of the projection α; is obtained by fitting the contour of each parts of the projection to a mathematical equation y=bn/an(an-xn)1/n.
The degree of ratio to circle, φp defined as the ratio of an area of a figure by curve-fitting to that of a minimum circumscribed circle of the projection is given as follows; φp=a1b12b23b34b4)/(π/4)d02, where d0 is the diameter of the minimum circumference and is related to the major axis of the projection by an=a=d0/2, and b is the minor axis of the projection.
This type of analysis for a shape factor of projection is named as‘Curve-fitting method’.
The ratio to sphere, Ψt=φtφt' which is determined by the ratio of true area of the projection of a model particle to the area of a circumscribed circle for the same projection, coincides well with that determined by the‘Curve-fitting method’.
By using various kinds of model particles, the comparisons among the Wadells' degree of true sphericity, the space filling factor and the degree of ratio to sphere are carried out.
The results clearly demonstrate that the value of Ψp determined by the‘Curve-fitting method’ falls in between the other two quantities and that the degree of ratio to sphere for these model particles calculated from the ratio of the true area of the projection agrees fairly well with the ideal value.
• 高坂 彬夫, 松田 良弘
1975 年 24 巻 262 号 p. 600-603
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
The particle size determination of kaolin minerals by He-Ne gas laser extinction method has a good reproducibility when incorporated with either a batch method or a stopped flow method. Besides, the particle size distribution obtained by this method has a good correlation with that by an Andreasen pipette method.
This method is suitable for the on-the-process determination of particle size distribution by gathering slurry automatically through the by-pass from the process, diluting it carefully with water, and after adjusting the concentration, using a stopped flow method. The stopped flow method used in this research has such a disadvantage that it requires a long time for determination, because it makes use of a gravitational sedimentation of kaolin. But it is possible to make the required time shorter by using the centrifugal sedimentation.
The stopped flow method which uses a flow cell, with He-Ne gas laser as a light source is considered applicable to the determination of particle size distribution in the disposal process of factory wastes containing suspended particles and the control of particle size in the wastes as well as to the quality control in the production process of a factory.
• 海保 守, 栗原 現司, 近沢 正敏, 金沢 孝文
1975 年 24 巻 262 号 p. 604-607
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
The relationship between water vapor adsorbing property and angle of repose was clarified on glass beads sample. The amount of adsorbed water was measured by the volumetric technique, and the thickness of the adsorbed layer was estimated from a water adsorption isotherm of the sample. The angle of repose of the beads under various water vapor pressures was determined by the revolving drum method.
From the avalanching number (n) in the sample bed during one revolution of drum, the difference between critical angle of repose and angle of rest, Δθ, was evaluated to be 360°/n. It was found that Δθ increased in proportion to the rotation velocity (α) of drum. The value of Δθ under a static state (Δθ0) was calculated by extrapolating the liner Δθ-α plot to α=0. Two kinds of α values were defined as follows:
pulsating flow_??_αmaxαmin continuous flow
The time dependence of Δθ was observed under a water vapor pressure where the thickness of water adsorbed was less than monomolecular layer. When the amount of water exceeded two-molecular layers, the three factors, i.e. Δθ0, αmax and αmin, were found to increase considerably. These tendencies were considered to be caused by enhancing adhesive force due to the adsorbed water molecules between the glass bead particles.
• 梅屋 薫, 関口 勲
1975 年 24 巻 262 号 p. 608-612
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
The relation between stress and strain in the compaction of dry powdered materials is generally given by Tani's equation (σ=kεn). On the other hand, the σ-ε relation of damp powders under low compacting stress must be corrected in accordance with the progress of compaction because of the agglomerative nature of floclike mass. As has been reported previously, the σ-ε relation of damp powders which does not bring about deformation and cracks of constituent particles is shown as σ=kiεni+di, where subscripts refer to the consecutive opposing processes of three stages.
The consistency of damp powders dealt with in this work follows the relation given above, and also the expressions for three stages of compaction are newly characterized by
Kψi=(σ-di)(1+bi)-1·ε-1
where Kψi=ki(1+bi)-1, di=ci/(1+bi), ni=1+bi, and these constants depend on the mechanical properties of particle packing structure. In particular, the degree of performance for the compaction of damp powdered materials can be expressed better with the help of consistency constant Kψi. It appears that the above relation is useful enough to yield an understanding of the packing mechanism of damp powder beds.
• CdS粉末の表面状態の変化
竹内 学, 金子 冨士男, 長坂 秀雄
1975 年 24 巻 262 号 p. 613-616
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
The effect of ball milling on the surface condition of CdS powders was investigated. The sample powders were precipitated from aqueous solution of cadmium sulfate. The mean particle sizes of the precipitates were about 10 and 2μm. The sample powders were ground in an alumina ball mill for different periods from 30min to 240hr. In the early stage of the grinding process, the particle size of the specimen having the initial particle size of 10μm decreased rapidly to about 2μm and it did not decrease any more even if grinding time was prolonged. On the other hand, the particle size of the specimen having the initial particle size of 2μm did not decrease any more. However, the degree of structural imperfections increased with increasing grinding time for both specimens.
Using an interdigital electrode, the decrease in photocurrent associated with an adsorption of oxygen has been measured. The magnitude of the decrease in the photocurrent of ground CdS powders became larger with increasing grinding time. This suggests that the structural imperfections, generated by ball milling, act as adsorption sites for oxygen molecules.
Corona-charging potentials of ground CdS powders have been measured as a function of relative humidity. The initial surface potentials decreased with increasing grinding time over a whole range of relative humidity for all specimens. This is attributable to a decrease in apparent resistivity of the powder layer, which is associated with an increase in adsorbed moisture. The adsorption of ambient moisture is enhanced by the ball milling.
• 貞広 嘉和
1975 年 24 巻 262 号 p. 617-621
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
The lattice distortion and crystallite dimension of ground ZnO powder by a ball mill and a vibrating mill have been studied by X-ray diffraction and electron spin resonance methods.
The following results have been obtained.
(1) The intensity of the absorption line of g=1.96 decreases with decreasing crystallite dimension. This absorption is probably due to the surface defects.
(2) The line of g=2.006 is the overlapping of absorptions due to the surface and internal defects related to oxygen. These two absorptions have nearly equal g values but different line shapes. The intensity of the line increases with increasing lattice distortion.
(3) The intensity of the line of g=2.013 increases with increasing grinding time and this absorption is due to the internal defects.
• 椿 淳一郎, 神保 元二, 和出 良一
1975 年 24 巻 262 号 p. 622-626
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
In this report, the analysis of the circumferential line of projected figure on a particle by using a stylus profilometer (graf-pen digitizer) is proposed for the shape characterization of particles.
The circumferential profile is digitized and converted to x, y values, so as to feed it to computer calculation, and then, the center of gravity is obtained by calculating the moment of a mass (area). Then, this circumferential line is unrolled around the center of gravity against angle θ.
From this unrolled line, the projected area diameter, Ds, the diameter of the circle of equal perimeter, Dl, and the average value of R, Rm, are calculated, where R is the distance between the center of gravity and the circumferential line. With these diameters, three circularities, ψ(=Ds/ Dl), ψs(=2Rm/Ds) and ψl(=2Rm/Dl), are defined as the characterization of the shape of a particle. As the examples, three models (roundness, concave, convex) and four materials are selected, and three circularities are calculated.
From these results, it can be found that when the shape of particles is characterized properly, the values of some circularities show very sharp distribution and consequently particle can be clearly identified from other particles. For example, iron powder can be identified more distinctly by ψl value, and limestone, by ψs value.
• 諏訪 佳子, 杉本 良樹, 中 重治
1975 年 24 巻 262 号 p. 627-631
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
The submicron samples of barium titanate were prepared by (1) the hydrolysis of titanium iso-propoxide in barium hydroxide solution (BT-I), (2) the simultaneous hydrolysis of barium iso-propoxide and titanium iso-propoxide (BT-II), and (3) the grinding of barium titanate prepared from barium carbonate and titanium oxide (BT-III) in iso-propyl alcohol or in air, and the species adsorbed on their surface were examined by means of TGA, DTA and IR spectroscopy.
On the as-prepared BT-I having the particle size of 100 to 300Å, the surface species identified were the hydrogen-bonded hydroxyl group, iso-propyl or iso-propoxy groups, the carboxyl group and the carbonate ion. Adsorbed alcohol began to be removed at about 200°C and all species disappeared completely above 800°C.
On the as-prepared BT-II having the particle size of about 100Å, the concentration of the iso-propoxy group and the carboxyl group seemed to be higher than those of as-prepared BT-I. Since the carbonate ion was not found on the as-prepared surface but appeared on heating it at 500°C, it is suggested that the carbonate ion would be formed from the carboxyl group.
When the BT-III was ground in iso-propyl alcohol, its IR spectra were similar to those of the as-prepared BT-I, but when ground in air, the large broad doublet spectra appeared in the stretching vibration region of carbonate salt, suggesting the monodentate bonding of the carbonate ion on the barium ion site.
The difference of the surface species and of the bonding character are considered to be related to the preparation method, the character of the surface ions, and the surface activity or the space charge layer near the surface of ferroelectric fine powder.
• 宇津木 弘, 松沢 敏晴, 阿子島 明美
1975 年 24 巻 262 号 p. 632-637
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
The silica gels were treated with the hexane solutions of several kinds of alicyclic alcohols at the critical point of n-hexane in an autoclave. After completion of reaction the vapor of both unreacted alcohol and water was vented out of autoclave to avoid the contact of these vapors with the treated silica gels. These gels showed the hydrophobic and lyophilic nature, since they were preferentially dispersed into oil phase when dispersed into the mixture of disperse media which are immiscible with each other like oil and water. All of these properties, such as the numbers of surface group obtained from their carbon contents, the relationship between their argon surface areas and numbers of surface group and the relationship between the inner surface area composed of the unreacted silanol in the micropores covered by a surface group and the molecular cross sectional areas of alcohols used, showed the same trends as reported previously. Furthermore the characteristic absorption due to surface groups observed in the infrared absorption spectra of the treated silica gels indicated that the surface groups were composed of alcoxy group of alcohols used. The ratio of characteristic absorption coefficient due to the surface group and that at 800cm-1 due to skeltal vibration of the treated silica gel, _??_Si-O-Si_??_ follows the Lambert-Beer's law against the ratio of molar concentration of carbon and that of silica in KBr disc. Since the molar extinction coefficient of absorption due to the surface group showed a constant value against the number of surface groups, the surface group of silica gels treated with alicyclic alcohol was not the physisorbed nor chemisorbed alcohol, but chemically bonded as an alcoxy group to Si on SiO2.
• 宇津木 弘, 松沢 敏晴, 阿子島 明美
1975 年 24 巻 262 号 p. 638-642
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
The reflux method has been used to modify the silica gel surface with alcohols, in which the water produced through the treatment was taken out of the reaction system by collecting it on the bottom of side tube and the long chain hydrocarbons (with high boiling point) including the unreacted alcohols were refluxed and recycled into the reaction vessel. The following two procedures were performed to investigate the effect of the above-described reflux method; (1) the silica gels were initially dehydrated in tetradecane at various temperatures and then treated with cetyl alcohol in tetradecane at the same temperature as that of the dehydration and (2) the silica gels were initially dehydrated in the various hydrocarbons at their respective boiling points and then the alcohols with boiling point similar to that of hydrocarbon used were added to treat the silica gels at their boiling points. It was found from the data of elementary analysis and argon surface areas of surface-treated silica gels that the effective surface-treatment has been performed by the dehydration and the surface-treatment at 200°C or higher in the procedure (1) and by the dehydration in hydrocarbons with the boiling point of ca. 200°C or higher and the surface-treatment with alcohols with boiling point similar to that of hydrocarbon used in procedure (2). The silica gels after dehydration at 200°C or higher in the long chain hydrocarbons have shown the existence of residual and this residue cannot be completely eliminated even after well-washing with n-hexane. These gels have shown nearly 10% decrease in argon surface areas.
• 宇津木 弘, 松沢 敏晴, 阿子島 明美
1975 年 24 巻 262 号 p. 643-648
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
The silica gels treated with alcohols in long chain hydrocarbons by the reflux method have been investigated from the standpoints of the numbers of surface group, IR spectra, argon surface area and the preferential dispersion into mixed media like oil and water. The results revealed the similar trend in those properties of surface group to those for the surface-treated silica gels through the autoclave method reported previously. The surface group of silica gels treated with cetyl alcohol has been recognized to take the position parallel to the silica gel surface for a small amount of surface group, but changes to the vertical position when the number of surface group increases.
• 諸橋 昭一, 大家 隆義, 沢畠 恭
1975 年 24 巻 262 号 p. 649-653
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
An experimental study on the adsorption properties of ground Soma sand was carried out by the following three methods.
(1) Wet (M.B.): methylene blue is adsorbed during grinding in the solution,
(2) Wet (H2O): methylene blue is adsorbed immediately after grinding in water,
(3) Dry: methylene blue is adsorbed immediately after grinding in air.
The results obtained through this experiment are as follows.
(1) As the time elapsed after grinding becomes longer, the adsorption activity of the solid surface becomes lower. So the adsorption on a newly produced surface at the instant of fracture must be distinguished from the adsorption on an old original surface.
(2) A method for determining the adsorption orientation of methylene blue was examined. The specific surface area of the ground Soma sand particles obtained by this new method was almost equal to that of the nitrogen adsorption method.
(3) The amount adsorbed on the surface increases with increasing the newly produced surface and approaches finally toward the value only due to the newly produced surface.
• 測定法と粉体特性
荒川 正文, 西野 操
1975 年 24 巻 262 号 p. 654-659
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
The rheological properties of various powders have been measured by four different methods in order to examine the effect of particle characteristics on the flow phenomena of powder.
There are many methods available to estimate the rheological behaviour of powder. In the present experiments, the following four methods were used:
(a) Measurement of the rate of effusion of powder from an orifice,
(b) Measurement of the fluidity of powder in a vibrating state with the rotating cylinder viscometer,
(c) Measurement of the ratio of bulky density to final packing density, ρmaxmin,
(d) Measurement of the angle of repose of heaped powder.
The relation between the rate of effusion of powder and orifice diameter showed reasonable lineality in the log-log plotting. The slopes of these lines correlated with the values of ρmaxmin. Sample materials have revealed that graphs of effusion rate vs. particle size exhibit a maximum. The position of the maximum depends on the properties of the particle, such as rugosity and shape. The shear diagram obtained from the rotational cylinder viscometer under a vibrating state exhibits plastic flow. The magnitude of shear stress of the powder bed is caused by interparticle force and void ratio of the bed, but their effects are not independent from each other.
The influence of these particle characteristics on the flow behaviour of powder differs among different phenomena. Therefore, calibration is needed to obtain the apparatus constants and the correlation between the results of different methods. Some calibration data of flow characteristics of various powders have been obtained by comparing their effusion rates with that of the standard glass beads powder.
• 津々見 雄文, 栗 功
1975 年 24 巻 262 号 p. 660-663
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
When a particles bed packed in a cylindrical vessel was imposed on a centrifugal force field by rotating a horizontal disk at the bottom of the bed, the flows are in vortex motion except in the case of sticky bed. The authors studied such flow property.
The experimental results and the dimensional analysis give the following dimensionless expression.
[Pgc/nD4ρg]=Kμ'[h/D][ρnD2/μ]a[Dn2/g]b
where the left side term in parenthesis is the ratio of the drag force to the gravitational force, and in the right-hand terms K is a constant, μ' the dynamic friction coefficient between the bed and the disk's surface, the third term in parenthesis is the shape factor, h, the depth and D, the diameter of the bed, the fourth and the fifth terms are the Reynolds and the Froude numbers, respectively. As to the values of two constants a and b, a is -1/6 and b is 1/3 in the case of a typical dry operation, and they become -1/3 and 2/3, respectively, in case that water is added in amount to fill the voids of the bed.
This flow pattern seems to be effective for application in size reduction or mixing, because it gives strong centrifugal and shearing forces, but does not require such large power to be fed.
• 梅屋 薫, 関口 勲
1975 年 24 巻 262 号 p. 664-668
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
If the“crumbs”of agglomerates are formed in a floclike mass of damp powders, the agglomerate growth during the early stage of tumbling agglomeration may be analyzed from the stand point of appearance-disappearance process. In this case, if the coalescene of agglomerates is assumed to be the only pravailing mechanism, a rate equation of agglomerate growth which shows the first order process can be introduced.
It is derived from the above-mentioned consideration that, when agglomerate size data is fitted for the Rosin-Rammler type distribution (i. e., Rm=100exp(-Bx3)), the correlation for the arithmetic mean size of agglomerates, on the mass basis, to cumulative drum revolutions is represented by an exponential function. In the case of damp powders of pulverized limestone having a uniform size range by sieving, the rate constant, kn, of agglomerate growth is extremely sensitive to the moisture content more than about 60 volume %. This marked dependence of the rate constant on moisture content is similar to the data of Kapur et al. for comparatively finer limestone powders and for lower moisture contents. Furthermore, it is observed that the combined relation, (1-ε)φv, between void fraction and volume shape factor for the agglomerates encountered in the agglomerate size analysis is experimentally independent of cumulative drum revolutions.
• 船越 嘉郎, 山本 真樹, 荒木 征雄
1975 年 24 巻 262 号 p. 669-672
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
When a kneaded mass is put into a die and pressed between the upper and the lower punches, the total applied pressure is not perfectly transmitted between these punches because a part of the compression energy is consumed as the friction energy against the side wall.
This transmission degree of the compaction force in the die is proposed in this paper as a measure to describe the kneaded degree of materials.
This method provides the most generalized measuring means because the kneaded character can be obtained independently regardless of the kinds of kneading equipment.
• 船越 嘉郎
1975 年 24 巻 262 号 p. 673-676
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
It has not been clear enough in which stage of the ejecting process of the compacts so-called capping defects appear in the ordinary tablet making process. Train has pointed out that these capping defects may generate when the compacts leave the die part. In order to investigate these capping defects produced in the compacts, a newly constructed apparatus named“Drilling load measuring device”has been utilized in the present study. The results clearly show that some weak structure appears in the compacted mass when the compression force applied to this powder bed is removed and this weak structure grows up to become cracks during the ejection procedure.
• 坂本 宏
1975 年 24 巻 262 号 p. 677-681
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
In this paper, the strength of dry pellets formed from fine grains of glass, feldspar, hematite, and quartz was investigated.
From the experimental results, it has been found that the strength of dry pellets of the ground products can be expressed by the equation (1) which is a modified theoretical tensile strength equation for the dry pellets of spheres obtained by introduction of the idea of maximum porosity for uniform packing structure of the ground material. It is recognized experimentally that a, b, and H in Eq. (1) change with the shape of particles.
S=1/Dav2·{31(a-ε)2+1}·eb(a-ε)·H (1)
where S is the tensile strength of dry pellets, Dav is the mean diameter, a is the maximum porosity, ε is the porosity of pellets, b is a constant and H is the bonding force at point of contact.
• 坂下 幸司, 渡辺 治夫
1975 年 24 巻 262 号 p. 682-685
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
The sedimentation rate of multiparticle suspension in a stationary fluid, um, decreases with increasing particle concentrations. The voidage function F(ε) is defined as F(ε)=v/um, where v is the terminal velocity of single particle in the infinite stationary fluid.
In order to generalize the voidage function to cover the entire ranges of flow, namely, laminar (St), intermediate (Al), and turbulent (N) flow regions, the following equation is given.
FSt(ε)=[FAl(ε)]m=[FN(ε)]2
where m varies from 1 to 1.63 continuously with Reynolds number in the intermediate flow region, when calculated from the drag coefficient correlation of a single sphere motion according to Schiller. Previously, Richardson-Zaki has pointed out that m varies from 1 to 2 in the same intermediate flow region and some other investigators reported m to be 1.4 or constant.
The voidage function in each flow region, obtained from the correlations of Kozeny-Carman or Ergun, has been found in good agreement with the voidage function of Richardson-Zaki in a certain range of voidage.
• 佐藤 輝昭, 渡辺 治夫, 小幡 英二
1975 年 24 巻 262 号 p. 686-689
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
It is necessary to take particle sedimentation into account, especially in the case of a gravitational pressure filtration.
The time for filtrating the slurry which has the settling tendency was found to be longer than that without sedimentation, because the filter cake is formed immediately and the maximum cake resistance is attained before the completion of filtration.
The ratio of filtrating duration to the duration necessary for filtrating the instantaneously settled slurry has been defined as τ and the following formula has been obtained to express the general filtrating characteristics, which agree well with the experimental results in the batch constant pressure filtration.
τ=1/φ[1+Ψ+φΨ/φ{exp(φ/1+Ψ·V/VE)-1}-V/VE]
• 1975 年 24 巻 262 号 p. 690-692
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
• 母数推定の統計的手法と安全寿命の決定-その2
石川 浩
1975 年 24 巻 262 号 p. 693-703
発行日: 1975/07/15
公開日: 2009/08/20
ジャーナル フリー
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