Showing papers in "Powder Technology in 1995"

TL;DR: In this paper, a model describing the size and density separation of granular materials undergoing gravity flow down a rough inclined chute is analyzed and a dynamic model is developed on the basis of an equivalent mass transfer equation taking into account the mass transfer due to convection, quasi-diffusion and segregation.

TL;DR: In this article, a population balance model is developed to describe the drum granulation of feeds with a broad size distribution (e.g. recycled fertiliser granules), where granule growth by coalescence is modelled with a sequential two-stage kernel.

TL;DR: In this article, a new correlation between particle size distribution and surface area has been established and models which include the size distribution, surface area and chemical composition as factors have been developed to predict cement strength based on a large data base generated from industrial surveys.

TL;DR: In this paper, the difference between ball mill grinding and stirred ball milling is discussed and a size energy model is proposed for simulation of stirred-ball milling, which has only two parameters.

TL;DR: In this paper, a non-intrusive local averaging technique was developed to compute bulk stresses from the values of local interparticle contact stresses which allowed us to monitor the changes in the orientation of the major principal normal stress as well as the magnitude of the shear stress in different hopper sections.

TL;DR: In this article, the random packed states for some nonspherical particles were investigated by computer simulation and good agreement was found between the computer simulated and experimental values of the packing density for random close packing.

TL;DR: In this paper, a 0.152 m diameter stainless steel fluidization column was constructed which can operate at closely regulated temperatures up to 500 °C, and a wide range of experiments were performed at different temperatures using specially-prepared size fractions of FCC powders in various gases: air, argon, neon, carbon dioxide and Freon-12.

TL;DR: A particle image probe comprising a CCD camera and an image processing system has been developed for on-line monitoring of granule size distribution and shape in a fluidized bed granulation as discussed by the authors.

TL;DR: In this article, a 50mm diameter gas-fluidized bed was used to investigate the origin and propagation behavior of pressure waves in a 50-mm diameter manifold and the attenuation and amplification of pressure wave during propagation away from their sources were explained by the interaction between particles and the fact that forced oscillations of fluidized beds are coupled with propagating pressure waves.

TL;DR: In this article, a semi-empirical relation was proposed to measure the mean particle size, spread of the particle size distribution, particle density, and particle shape of loosely packed and tapped beds.

TL;DR: In this paper, the first application of a non-invasive capacitance tomographic technique to monitoring the behaviour of industrial-scale pneumatic conveyors was described, and the results showed that particle breakage rates are inversely related to the solids loading factor.

TL;DR: In this paper, a fluidized-bed coating process using the rapid expansion of supercritical fluid solutions (RESS) is described for the coating of fine particles in a 50 mm i.d.

TL;DR: In this article, a simple momentum probe was used to distinguish between upward and downward flow regions in risers with diameters of 66, 97 and 150 mm, and experiments indicated that a typical core-annulus flow structure existed only above the inflection point corresponding to the axial voidage profile.

TL;DR: In this paper, sound-assisted fluidization of nonfluent 0.5-45 μm catalyst particles has been studied with a 145 mm i.d. column and different amounts of solids of weight W ranging from 1 to 3 kg have been charged in the column, and within these ranges the kinds of curves for sizes of subclusters d s as a function of the frequency have been outlined.

TL;DR: In this paper, it is shown that at temperatures well below the softening (sintering) points of both the reactants and the products, particle agglomeration can occur during the process of product formation.

TL;DR: In this paper, the authors summarize what is known about the acoustic properties of suspensions of solids in a liquid and identify the methods that enable useful information to be extracted from sound speed and attenuation information such as particle size, concentration, and the mechanical properties of the constituents.

TL;DR: In this article, a pneumatic powder-dryer can be used for flash evaporation of surface moisture, where heat transfer dominates the drying phenomenon, and a stepwise calculation using the predicted heat transfer coefficient of the above equation predicts moisture and temperature profiles.

TL;DR: In this paper, the effect of moisture content on the agglomeration and bulk density of coal was investigated based on microscopic observation and the results indicated that the relative roles of the growth mechanisms such as nucleation, coalescence and snowballing are dependent on the moisture content.

TL;DR: The Dilation Method based on erosion-dilation logic is probably the most commonly used matrix based method, however, the recently introduced Distance Transform Method is more accurate, produces more data and is substantially quicker.

TL;DR: In this paper, a distinction is drawn between pressure waves and solids concentration waves in fluidized beds, and the experimental results are compared against the simpler pseudo-homogeneous models.

TL;DR: In this paper, the effect of confining walls on the settling velocity of variously shaped rigid particles in stationary Newtonian liquids has been investigated, and the effect due to the presence of bounding walls has been quantified in terms of a wall factor which is a function only of particle size and shape, and tube diameter in the low Reynolds number region ( <7).

TL;DR: In this article, the authors investigated the link between the form of the instantaneous and effective yield conditions and the flow function, and the resulting implications in the arching theories are critically assessed.

TL;DR: In this paper, a pure Paracetamol for direct compression was obtained through recrystallizing of crystals from a dioxane solution or suspension, which led to the production of sintered-like crystals exhibiting a polyhedric habit.

TL;DR: In this article, a void space network is presented for the simulation of mercury intrusion and the calculation of the absolute permeability of porous media, where the Laplace/Washburn equation within a percolation algorithm is simulated.

TL;DR: In this paper, a steady-state model of the flow structure and mixing processes in the upper dilute zone of a circulating fluidized bed (CFB), where variations in flow parameters with height are neglected, is presented.

TL;DR: In this paper, electron spin resonance spectroscopy (ESR) measurements of the mechano-radicals produced from ground quartz and quartz glass were studied, and three mechano radical types were produced: E'center, nonbridging oxygen hole center (NBOHC) and peroxy radical.

TL;DR: In this paper, a computer-controlled mixing apparatus was used to investigate the mixing of glass beads in a cylindrical vessel rotating about its axis and rocking in the vertical direction.

TL;DR: In this article, the authors describe medium scale tests on symmetrical, plane (wedge-type) and conical hoppers aimed at determining the critical outlet size preventing the formation of arches or domes during gravitational discharge of bulk materials.

TL;DR: In this article, the cluster size distribution and motion behavior in a fast fluidized bed have been measured systematically by using two optical fiber probes and a computer data acquisition system, and the measurement results showed that although clusters behave in a transient nature, sometimes aggregating and sometimes dispersing, the local time-averaged cluster lengths remain almost constant radially in the core region of both the upper dilute section and the lower dense section, but the local cluster lengths in lower dense area are larger than those in the upper-dense area.

TL;DR: A new analytical solution for the cumulative batch grinding equation for first-order breakage has been proposed that involves no iterative technique but does not rely on any approximation either.