Showing papers in "Powder Technology in 2002"

TL;DR: In this paper, the authors presented a numerical and experimental study of the angle of repose of mono-sized coarse spheres, a most important macroscopic parameter in characterising granular materials.

TL;DR: In this article, it is shown mathematically that if a pressure dependent term is used in the Heckel equation then the resulting modified equation is very similar to the Kawakita one and, in fact, becomes identical in form for a particular value of the pressure dependency term.

TL;DR: In this paper, the authors investigated the fluidization of six kinds of SiO 2 powders, with high void fractions and sizes from 7 to 16 nm, and found that the quality of fluidization was not the Geldart-C expected with these nanoparticles, but has a free, much looser dynamic behavior with an extremely high bed expansion that obeys the Richardson-Zaki equation.

TL;DR: An overview of the current state of the art is provided, along with a discussion of expected research trends and their economic and societal impacts in this paper, where the anticipated role of nanotechnology is discussed in some detail.

TL;DR: In this article, the synthesis of nanoparticles using dry flame technology has been studied in the context of heterogeneous catalysts, which can be used to produce highly active nanoparticles with closely controlled morphology and composition.

TL;DR: In this article, the properties of clusters of particles travelling near the riser wall are predicted from experimental data published in the literature on vertical risers ranging from laboratory to industrial scale, and expressions for predicting the size, shape, density, wall film coverage and velocity of particle clusters are presented.

TL;DR: In this paper, the effect of stress intensity, stress number, and specific energy on the product fineness is determined by the breakage characteristic of the material and two main groups can be distinguished: deagglomeration and disintegration and secondly, grinding of crystalline materials.

TL;DR: In this paper, the authors proposed a three or four-dimensional population balance model for wet granulation, which includes granule size, porosity, binder content, and composition as independent granule properties.

TL;DR: In this paper, a rapidly disintegrating tablet was developed using both direct compression and wet compression methods, and tablet properties, such as porosity, tensile strength, wetting time and disintegration time were evaluated.

TL;DR: In this paper, the surface characteristics of hydrous silica-coated TiO2 particles are experimentally studied using high-resolution transmission electron microscope (HRTEM), ζ-potential analyzer and X-ray photoelectron spectroscope (XPS) analyses.

TL;DR: The quest to produce fully dense nanostructured ceramics has received much attention over the past 10 years as mentioned in this paper, and a short review highlights some of the progress made and indicates some avenues where further research should prove fruitful.

TL;DR: In this article, a method for quantitative in-situ measurements of the chemical content of powder mixtures is presented by means of near infrared spectroscopy (NIR) and a fiber-optic diffuse reflection probe inserted into the powder in the blender, determinations of the powder mixture content can be made during processing.

TL;DR: In this paper, a model based on the elastic-plastic theory and a yield function is used to limit the admissible stresses in a tablet during a compaction cycle, which depends on the first and second invariants of the stress tensor: pressure and stress deviation.

TL;DR: In this article, a continuous air gun was used to examine the effect of particle velocity, impact angle, particle diameter, target material, target thickness and number of impacts on the fragmentation of spherical aluminium oxide particles.

TL;DR: In this paper, the authors measured the flow stress of partially saturated pellets at deformation velocities varying from 0.01 to 150 mm/s, and found that viscous forces are negligible at low strain rates, but become dominant at high strain rates.

TL;DR: In this paper, the effect of high temperature and particle size distribution (PSD) on minimum fluidization velocity (U mf ) was studied. And the experimental results revealed a minimum in U mf near 800 °C.

TL;DR: In this article, powder surface velocities as a function of impeller speed were measured using high-speed video equipment and MetaMorph image analysis software and confirmed that for drop-controlled nucleation, the powder surface velocity should be less than 0.1.

TL;DR: In this paper, the authors proposed a method by which rolling resistance and contact anisotropy may be introduced in a micropolar model of granular media to capture key microstructures like shear bands.

TL;DR: In this paper, the clathrate compounds of methane gas hydrate (MGH) were synthesized in laboratory at a temperature of 273.5 K and at a pressure of 6.8-13.6 MPa.

TL;DR: In this article, the authors exploit the link between damage accumulation that takes place during a single impact and the progressive weakening that occurs after repeated impact, ultimately resulting in a broken particle.

TL;DR: In this paper, the feasibility of using dense CO 2 with the technique known as the Aerosol Solvent Extraction System (ASES) to micronise and microencapsulate para-hydroxybenzoic acid (p -HBA) and lysozyme, with a bio-erodible polymer, poly( l -lactic acid) ( l -PLA), from various organic solutions, was examined.

TL;DR: In this paper, a solvothermal synthetic method to nanocrystalline titania has been carefully investigated in alcohol solutions and the products were also characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman as well as UV-VIS spectroscopy.

TL;DR: In this paper, experimental flow patterns, determined by Laser Doppler Anemometry (LDA) for two types of reverse-flow centrifugal separators, are presented.

TL;DR: In this article, the influence of pressure on the flow structures and regime transitions in dense gas-fluidized beds using the discrete particle simulation (DPS) approach was analyzed to highlight the intrinsic mechanisms underlying the gas-solid flow patterns and elucidate elevated pressure-induced improvement of fluidization quality.

TL;DR: In this paper, the interaction between fuel particles and incipiently bubbling gas fluidized beds during devolatilization has been investigated by X-ray imaging, where a purposely designed single-particle-injector was used to impulsively introduce fuel particles one at a time at a given depth into the fluidized bed.

TL;DR: In this paper, numerical simulations based on an Eulerian approach of a freely bubbling fluidized bed (BFB) are performed where emphasis is put on the importance of the inlet boundary conditions (influence of the pressure drop of the air distributor on the state of fluidization).

TL;DR: Theoretical models for calculation of the bed turnover time in both the slumping and rolling modes and the transition from slumping to rolling transition in rotating drums with less than 50% volumetric fill of free-flowing granular materials are presented in this paper.

TL;DR: In this article, the influence of initial powder particle size and electrical pulsing on microstructure, including the presence and distribution of porosity, cracks and particles, density and microhardness are detailed.

TL;DR: In this paper, the hydration capacities of different wheat flours (resulting from each stage of milling) were measured according to three different methods based on centrifugation and on capillary suction.

TL;DR: In this article, the effects of fill level, mixing time, and use of baffles on the mixing performance of a pilot plant scale tote (bin)-blender were investigated.