In the antacid activity test, artificial aluminum silicate differs very much from aluminum hydroxide gel in neutralizing velocity and the total quantity of comsumption of 0.1N-HCl. This difference occurs also in the series of aluminum silicate which change the pH condition of co-precipitation or the composition of aluminum. Here aluminum silicate samples prepared by various available methods were measured by X-ray diffraction, IR-ray absorption and differential thermal balance. Furthermore, the shapes and sizes of this first and aggregate particles were estimated by observing the electron microscope photograph. As the result obtained, the above mentioned antacid property of artificial aluminum silicate has effectively been explained comparatively in its bonding state, in the aggregate shapes of its particles and in its electrically charged state at co-precipitation.
In order to elucidate the hot-pressing process of granular materials, studies were made of the effects of compacting pressure and temperature on the structure of polystyrene powder compact. The kinetic studies showed that within the temperature and pressure range studied, the relation between the percentage of shrinkage S of the powder compact and the compacting time t was expressed by an empirical equation, S=Atk (t>30sec), in which k was an apparent rate of shrinkage. At a given compacting pressure the temperature dependence of the apparent rate of shrinkage k is characterized by a sharp maximum at a critical temperature Ts. It was found that the critical temperature did not depend on the shape and size of powder particles as was characteristic of polystyrene. This Ts decreased gradually with increasing compacting pressure. The powder compacts had different pore structures depending on the compacting conditions. Thus, for those prepared below Ts pore size and its distribution remained almost unchanged with compacting time, whereas for those above Ts a remarkable change was observed in both of them. As a conclusive summary of these results and discussion, two different mechanisms of hot-pressing of polystyrene powder compacts were suggested, i.e., local deformation of the powder at the contact points below Ts and the overall deformation caused by the softening of polystyrene above Ts. The results of microscopic observation are in favor of the suggested mechanisms.
Assuming constant curvature of water profile and zero contact angle, the approximate adhesion forces by surface tension between a spherical particle or a conical point and a spherical or flat surface in several typical conditions have been geometrically analyzed and numerically calculated. The adhesion forces at the narrowest portion of the water pendular ring (film) are usually smaller than those at the contact line on the particle. Therefore, the former seems to be the real adhesion force between the two bodies. The obtained results may serve to explain the effect of surface configuration or liquid quantity on the adhesion force, and to verify various experimental phenomena. For example, if the two bodies are in contact with each other between the conical point and the spherical surface, the larger humidity in the surrounding atmosphere, the larger the adhesion force between them. On the other hand, if the two spherical surfaces are in contact, the larger the humidity, the smaller the force. Furthermore, the adhesion forces of the two separate bodies by water pendular ring have been calculated too. They are usually smaller than the adhesion forces of the two contact bodies, and the adhesion of the two bodies may be stable when they are in contact.
In this paper is shown the improved method for measuring the adhesion force of powders to flat plates in centrifugal field, which requires no special preparation of sample powders (e.g. size classification) and less measuring time than others. The materials, the shape of the powders, the relative humidity of atmosphere and the contact time of the powders to the glass plate are selected as variables. It is found that the experimentally obtained curves of separation force vs. the residual percentage of the adherent particles on the plate (separation-residual percentage curve) is well represented by the logarithmic normal distribution, Eq. 3, as shown in Fig. 4. So separation-residual percentage curve is determined by the separation force at 50% residue (f50) and the variance of the curve σ=f159/f50) The experimental results obtained are summarized as follows, (1) The adhesion force is variable dependent on the materials, and especially on the shape of the particles, as shown in Fig. 11. (2) The adhesion force is independent of the size of the particles within the range of 15∼30μ. (3) The adhesion force increases along with relative humidity, and the effect of its contact time on that tendency varies according to the materials. (4) The mechanism of adhesion of powder to the flat plate can be investigated and presumed by f50 and σ.
An experimental study was carried out on the process of radial mixing in the horizontal cylinder type batch mixer from the view point of circulation flow of particles occasioned by the transportation of particles in the zone of static mass. The experiments were made, on the binary component system, with a two-dimensional horizontal cylinder mixer of 9cm radius and 1.5cm thickness having 39 sampling holes, using for mixing components Soma sand of 1 mean mm particle size, a part of which was dyed in red for detecting. Samples, each containing on the average 100 particles, were drawn with plastic pipe sampler of 4mm diameter to analyse the distribution of concentration and determine the degree of mixedness of the mixture. The width of static mass was measured and the values were correlated with running speed N and charge ratio F/V. The mean circulation time T was calculated with the values of h for various operational conditions as shown in Table I. The time variation of two mixedness; one is Mmax based on the maximum concentration Cmax in the mixture and the other M, the whole mean sample was observed too. The rate of mixing for both the mixedness can be expressed by the mean circulation time T. In the process of experimental work, several informations were obtained also to analyse the mechanism of mixing in the horizontal cylinder mixer.
The purpose of this investigation is to determine the available equations for design of table feeder. Taking note of the piled-out length M, the discharge-rate equation has been derived theoretically as Eq. (11). The calculated results of the discharge rate are in good agreement with the observed data as illustrated in Figs. 9∼11. It has been observed that the value of M decreases as the insertion length of scraper increases, but finally M becomes constant value Mc at a critical distance between the scraper and the discharge pipe sc. These values of Mc and sc can be determined by Eqs. (9) and (6), respectively. Assuming M≥Mc, the empirical equations on M have been obtained as Eqs. (2) and (3). The equations reported here may be actually available when the discharge rate is predicted from the operating conditions.