Showing papers in "Powder Technology in 1983"

TL;DR: In this article, the spatial probability distribution of tracers in a large-scale heap was investigated in the presence of a small tracer component in a close-sized bulk material.

TL;DR: In this paper, a simple model of a 2-component mixture of spherical- or disk-type particles was proposed for estimating the coordination number, which is the number of contact points on a particle.

TL;DR: For a wide range of bed and sphere sizes, porosity varies significantly and regularly near the container wall as discussed by the authors, for uniformly sized spheres, the oscillations in porosity can be detected up to a distance of about 5 particle diameters from the wall.

TL;DR: In this article, a model system of paracetamol wet granulated with six common tablet binding agents was employed for the evaluation of binder efficiency, and the authors established criteria for evaluating binder performance.

TL;DR: A dip or fish-hook in the fine end of the selectivity curve for hydrocyclones has been reported on several occasions as mentioned in this paper, which is modelled by introducing an entrainment component to recovery to the underflow which is a function of particle size.

TL;DR: In this paper, a linear relationship between N/C and N is obtained as shown in Fig. 3 as well as from the traditional results and no unusual phenomenon was observed, moreover, it is found that Kawakita's formula relating to compression is applicable and a comparison between the various kinds of powder solids can be made by physical interpretation of the constants in his formula.

TL;DR: In this article, theoretical and experimental work on the effect of interstitial air pressure on the flow of granular materials from hoppers is presented, and a theory is developed for the case of low Reynolds number flow in a conical hopper.

TL;DR: In this article, the validity of the assumptions built into the two-phase theory has been re-examined for a range of fine powders, and the systematic deviations from the above assumptions demonstrated.

TL;DR: In this paper, the authors compared the adherence pattern of powder and conditioner particles in scanning electron micrographs of the untreated and conditioned powders and found that conditions tended to aggregate with their own kind, and their effect on the bulk properties was merely through being a component in a random mixture.

TL;DR: In this article, a mathematical definition for choking in vertical pneumatic conveying lines was refined and presented with additional data, and the concept of continuity wave and cluster formation, which were successfully applied to predict the transition between the bubbling and the turbulent fluidization, were introduced to derive the basic relationship expected at choking.

TL;DR: In this article, the adsorption isotherms of n-octane, n-propanol and n-butanol on brasilian quartz were determined by the elution gas chromatography method.

TL;DR: In this article, a fine-grained optic fiber probe with a core diameter in excess of the particle diameter is used to detect free-falling particles at terminal velocity, and the carryover stream of a gas-fluidized bed is simultaneously probed and collected in a cyclone separator.

TL;DR: In this paper, the difference in the definition of particle size measured by the Microtrac instrument and by sieving has been investigated, and a methodology has been developed for estimating the equivalent sieve size distribution from the microtrac size distribution, provided that the size distribution can be approximated by a suitable mathematical function.

TL;DR: In this article, the formation of hydraulic jumps in the open channel flow of dry, cohesionless granular materials was investigated and the experimental observations include the identification of several types of jump and several types downstream flow.

TL;DR: Choking in vertical pneumatic transport in the presence of electrostatics was examined using a 0.0254 m dia. plexiglas tube and 150 μm dia glass particles.

TL;DR: In this article, a theory of tensile strength for single powders and binary mixtures was developed by means of equations incorporating the particle size parameters and the compositions of binary mixture.

TL;DR: In this paper, the tablet strength of powder formulations containing binder levels of 80, 50 and 20 wt.% incorporated by dry mixing, are monitored, and the ability of the binder to adhere to the substrate under pressure, as quantitated by an adhesive index A, is the most significant influence on binder efficiency.

TL;DR: In this article, the unsteady-state, one-dimensional convective mixing equation was solved with finite end boundary conditions for a pulse of tracer admitted into a steady flow, assuming a constant dimensionless mixing factor D*.

TL;DR: In this article, the authors presented a preliminary model based on the simple binary system of component B occluded in a matrix of component A, for the case where fracture planes can pass with equal ease through A or B. The model was programmed for Monte Carlo simulation, and an analytical solution was also developed using a synthetic "mineral-host matrix" particle.

TL;DR: In this paper, the global equations of balance for particulate media and via a special ensemble averaging technique, the local equations governing the mean motion and the random fluctuations in a rapid flow of granular materials are derived.

TL;DR: In this article, the onset of slugging in gas was studied by means of pressure transducers coupled with the on-line cross-correlation technique, and the rise velocity of bubbles was employed as the criterion for the onset.

TL;DR: In this paper, a model for estimating the coordination number of a mixture of uniform-sized cohesive particles, using the angle of friction between spheres, was proposed and compared with those obtained from computer simulation of a two-component mixture of cohesive spheres and fairly good agreement is found between the calculated results and the simulated data.

TL;DR: In this paper, an apparatus was developed to measure the ejection forces with varying radial forces for the tablets compressed at a definite compressive force apart from the apparatus, and a linear relation between ejection and radial forces was obtained.

TL;DR: In this article, the entrainment of fine FCC particles from a three-dimensional fluidized bed was studied and the velocities of particles leaving the bed surface and moving in the freeboard, those of bubbles rising in the dense bubbling zone, and the hold-up of solid particles in freeboard were measured continuously by optical probes.

TL;DR: In this paper, the holdup of fine particles in the packed bed of dense particles in a multisolid pneumatic transport bed was experimentally examined and an interaction coefficient between fine particles and dense particles was defined based on the momentum balance equation.

TL;DR: In this paper, the results of experiments on beds of ternary mixtures of 2, 1 and 0.5 mm spherical glass beads under laminar flow conditions were presented in the form of a diagram of isopermeabilities from which the standard permeability of any mixture in the teranary system used can be read off directly.