Showing papers in "Powder Technology in 1990"

TL;DR: A review of the major development in solids mixing since 1976 can be found in this paper, where the publications on the subject have been divided into three major categories: characterization of states of solids mixtures, rates and mechanisms of solid mixing processes, and design and scale up of mixers or blenders.

TL;DR: In this paper, the effect of particle size distribution on the structure of hard spheres in 3D was studied by means of Monte Carlo simulation, and it was shown that the pore structure of the loose random packings is such that particles with radii up to 0.15 units can percolate through the sediments.

TL;DR: In this article, the authors compare and validate computations of flow pressure drop in a cyclone separator by an analytical solution with approximation of constant viscosity and solution based on the k -ϵ turbulence model.

TL;DR: In this paper, the decay constant for the fall off of bulk density of solids with height in the freeboard is modeled as a logarithm of the velocity of the column.

TL;DR: In this paper, Johnson's S B function is suggested to represent all the unimodal size distributions of particles and its applicability is proved from the theory of distributions in statistics.

TL;DR: In this article, the results of a triaxial test with dry sand, sugar, rape, wheat and synthetic granulates are presented with a view to facilitating development and checking of appropriate constitutive equations.

TL;DR: In this paper, a Two-Dimensional Steady State Two-Phase Hydrodynamic Model is developed to describe gas-solids flow behavior in dilute gas solids flow systems.

TL;DR: In this article, a simple sampling probe is developed and tested and found to be successful in measuring radial solids flux profiles in the riser of a cold model circulating fluidized bed.

TL;DR: In this paper, the fluidization characteristics of a hardmetal powder, of extremely high density and small primary particle size such that it belongs to Group C in Geldart's classification, has been investigated.

TL;DR: In this paper, a modification of the gas flow technique first proposed by Ergun for flow through packed beds proved to be the most suitable method; the sphericities found can be used to predict particle terminal velocities even in the transitional flow regime, by means of interpolative correction factor.

TL;DR: In this paper, the authors review developments in the design of new shear testers and present some new results of the experimental work carried out with shear tester and present a short description of measured flow properties of bulk solids.

TL;DR: In this paper, the significance of wettability, polarity and surface energy of powders with respect to their usage is discussed in terms of spreading coefficients, and indications as to how surface energies can be used to predict interactions are given.

TL;DR: In this article, a one-dimensional model is developed to account for rapid variations of vertical voidage in these calculations, which explains the discrepancy observed by Arena et al. between the voidage profiles inferred from pressure gradients and those measured by quick-closing valve technique.

TL;DR: In this article, a method based upon digital image analysis has been developed to automate the measurement of bubble properties in gas-fluidized beds in order to identify the bubbles, the gray-level image is segmented by applying a global threshold.

TL;DR: In this article, the behavior of fluidized beds of ferromagnetic particles in the presence of an axial magnetic field is studied. And the experimental results enable the e e to enable the

TL;DR: In this paper, the mechanism of adsorption of polyethylene oxide on kaolinite was examined by studying the adsorbing/flocculation characteristics of different oxide minerals using the same polymer.

TL;DR: In this paper, the effects of particle properties and column size on the transition velocity to the turbulent flow regime have been determined in a 0.1 m-I.D. × 3.0 m high Plexiglas column.

TL;DR: In this paper, the fracture behavior of fine single particles of five minerals and two coals in a size range from 88 /gmm to 1 μm was investigated by compression tests.

TL;DR: In this article, the low shear rate viscosity was determined experimentally for suspensions of bimodally distributed polymethyl methacrylate (PMMA) spheres dispersed in silicone oil over a large range of particle volume fractions.

TL;DR: In this article, a review of new processes for the production of high-performance particulate materials are reviewed, with their implications for fluidized bed technology, including the use of coarse particles as turbulence promoters and mechanical vibration of the bed to attain stable fluidization with cohesive particles.

TL;DR: In this article, two sizes of fine coal have been transported at room temperature at pressures up to 82.7 bar through horizontal lines 6.25, 9.19 and 12.5 mm in diameter and up to 105 m long using nitrogen, hydrogen, and carbon dioxide.

TL;DR: In this paper, the authors describe a method by which a loose dust layer may be "prepared" for subsequent microscopic examination, which may yield quantitative data on its structure, and further treatment of the hardened cakes up to the point at which photographs can be taken.

TL;DR: In this paper, the tap densities of various compositions of Lactose-Avicel® and Emcompress® Avicel®, binary powder mixtures and the hardness values H 0, i.e., hardness values extrapolated to zero porosity, of the compacts were determined and used to confirm a percolation theory model set up for binary powder and compacts.

TL;DR: In this paper, an investigation of the behavior of gas-fluidized beds has been carried out in the presence of an external magnetic field, transverse to the gas flow and column axis, using different ferromagnetic materials.

TL;DR: In this paper, the effects of particle size distribution on the relative density of simulated isotropical compaction have been evaluated and the results of the isotropically simulated bodies can be applied to simulate Cold Isostatic Pressed (CIPped) bodies.

TL;DR: In this article, a technique to measure the effective dielectric permittivity of suspensions is described, where test powders are suspended in petroleum jelly at any desired voidage.

TL;DR: In this paper, the authors used digital image analysis techniques to obtain the pierced length and several size measures (maximum horizontal and vertical dimensions, circumference and area equivalent diameter) of bubbles intercepted at an ‘imaginary’ probe in a thin two-dimensional fluidized bed.

TL;DR: In this paper, the authors found that the measuring height on the axis of a bed was a very important factor for the determination of minimum fluidization velocity from the linear relationship between standard deviation and air velocity.

TL;DR: In this paper, the authors showed that there was a distribution of the maximum impact force even at a given velocity, due primarily to different orientations on impact, and the median impact force increased with impact velocity according to Y50αv6/5 as expected.