Effect Of Particle Length Research Articles

3D DEM Simulations and Experiments on Spherical Impactor Penetrating into the Elongated Particles.

In this study, a brass or glass spherical impactor vertically penetrating into a granular bed composed of mono-sized spherical or elongated particles was simulated with three-dimensional (3D) discrete element method (DEM). Good agreement of the particle masses in the cup before and after penetration can be found in the simulations and experiments. The effects of particle length (Lp), friction coefficient, and particle configuration on the penetration depth of the impactor, ejecta mass, and solid volume fraction describing the response of the granular bed are discussed. The penetration depth is negatively correlated with Lp as the corresponding solid volume fraction of the granular bed decreases. A smaller friction coefficient leads to a larger penetration depth of the impactor and more ejection of particles. When the impactor is penetrating the Lp = 10 mm elongated particles, the penetration depth is negatively correlated to the order parameter and solid volume fraction.

Evaluation and comparison the properties of acoustic boards made of date palm fiber

Applying acoustic panels made of natural fibers, due to their high biodegradable characteristics, light weight, low density, cheap price and non-toxicity, are proper alternatives to acoustic absorbers made of synthetic fibers. Considering their stance and vast applicability in industry, the possibility of producing them of natural palm fibers with sodium silicate adhesive of 10 and 20% in two 16 and 32 mm thicknesses, 350 and 450 kg/m3 densities, 50 and 100 mm particles length (strands), as variable factors in 16 types of matched panels with 3 repetitions is proposed in this article. The palm-trunk discs constituted the control sample. The effect of variables on sound absorption coefficient was assessed. The effect of variable thickness and adhesive percentage on all frequencies was significant and the effect of density variable on all frequencies except 250 and 2000 Hz was also significant. The effect of particle length was significant except at the 500 Hz frequency. The effects of all variables on porosity were significant. The results of this study suggest that by applying date palm-trunk (an agricultural waste) combined with sodium silicate adhesive, industrial environment-friendly panels can be produced with proper sound absorption coefficient in the field of acoustics. This 32-mm-thick panel was composed of 80% date palm-trunk particles of 50 mm length, 450 kg/m3 density, and 20% sodium silicate adhesive.

Sandwich Particleboard (SPb): effect of particle length on the quality of board

Sandwich particleboard is one of the composite products composed of strength lignocellulose materials for the surface layer and particle as the core layer. This product consists of three layers which are similar to comply. The difference between both products is in the surface layer, which uses veneer or thin plywood as surface. The objective of this research was to evaluate the length particle effect on physical and mechanical properties of SPB. Belangke bamboo, corn stalk bagasse and isocyanate resin were the main raw materials for the manufacturing of SPB. SPB was made in size of 25 x 25 cm with the density and thickness target of 0.7 g/cm3 and 1 cm respectively. Amount 8% level isocyanate resin was applied in the manufacturing of board. Hot pressing parameter such as temperature, time and pressure was set on 160 °C, 5 minutes, and 30 kg/cm2 respectively. The results showed that 10 cm particle length resulted in the best bending properties. MoE and MoR value of 10 cm particle length were 42, 156 and 333 kg/cm2 respectively. Almost all parameters fulfill the JIS A 5908 (2003), except the internal bond and the thickness swelling value.

Electric Field Distribution around Contaminating Wire Particles Inside Gas Insulated Bus Duct

The presence of metallic contaminating particles lowered the dielectric strength of the gas sharply. The determination of the insulation breakdown inside gas insulated bus duct requires the knowledge of the field distribution inside it. Finite Element Method (FEM) has been used throughout this work, for its favorable accuracy, to calculate the electric field distribution inside the bus duct. In this paper, the electrostatic modeling of gas insulated bus duct (GIBD) with particle contamination is studied. The effect of particle length, hemi-spherical radius and ratio (L/r) on the electric field values is presented. The effect of the dielectric coating of the inner surface of enclosure, is presented and discussed. Multi-contaminating fixed particles are considered in this work and the electric field distribution in this case is presented. The effect of particle length and radius of middle fixed particle of multi contaminating particles on the electric field values are also studied. Electric field distribution around disc-spacer with and without an earthed particle contamination is presented and discussed. Finally, the effect of distance between particle and spacer on the electric field values is also studied.

The effect of particle size on the thermal switching characteristics of metal particle tapes

The effect of particle length on the magnetic viscosity and high speed switching characteristics were studied for four experimental metal particle (MP) tapes. The particle length varied from 80 nm to 340 nm with diameters /spl sim/20 nm. The magnetic viscosity and activation volume were not sensitive to particle length. High speed switching measurements show only a moderate increase in the remanent coercivity at 10/sup -8/s. Results are compared to new models of magnetization reversal in acicular particles.

Sedimentation of particles in polymer solutions

In this paper, we present detailed and systematic experimental results on the sedimentation of solid particles in aqueous solutions of polyox and polyacrylamide, and in solutions of polyox in glycerin and water. The tilt angles of long cylinders and flat plates falling in these viscoelastic liquids were measured. The effects of particle length, particle weight, particle shape, liquid properties and liquid temperature were determined. In some experiments, the cylinders fall under gravity in a bed with closely spaced walls. No matter how or where a cylinder is released the axis of the cylinder centres itself between the close walls and falls steadily at a fixed angle of tilt with the horizontal. A discussion of tilt angle may be framed in terms of competition between viscous effects, viscoelastic effects and inertia. When inertia is small, viscoelasticity dominates and the particles settle with their broadside parallel or nearly parallel to the direction of fall. Normal stresses acting at the corners of rectangular plates and squared-off cylinders with flat ends cause shape tilting from the vertical. Cylinders with round ends and cone ends tilt much less in the regime of slow flow. Shape tilting is smaller and is caused by a different mechanism to tilting due to inertia. When inertia is large the particles settle with their broadside perpendicular to the direction of fall. The tilt angle varies continuously from 90° when viscoelasticity dominates to 0° when inertia dominates. The balance between inertia and viscoelasticity was controlled by systematic variation of the weight of the particles and the composition and temperature of the solution. Particles will turn broadside-on when the inertia forces are larger than viscous and viscoelastic forces. This orientation occurred when the Reynolds number Re was greater than some number not much greater than one in any case, and less than 0.1 in Newtonian liquids and very dilute solutions. In principle, a long particle will eventually turn its broadside perpendicular to the stream in a Newtonian liquid for any Re > 0, but in a viscoelastic liquid this turning cannot occur unless Re > 1. Another condition for inertial tilting is that the elastic length λU should be longer than the viscous length ν/U where U is the terminal velocity, ν is the kinematic viscosity and λ = ν/c2 is a relaxation time where c is the shear wave speed measured with the shear wave speed meter (Joseph 1990). The condition M = U/c > 1 is provisionally interpreted as a hyperbolic transition of solutions of the vorticity equation analogous to transonic flow. Strong departure of the tilt angle from θ = 90° begins at about M = 1 and ends with θ = 0° when 1 < M < 4.

Effect of Particle Length and Sodium Hydroxide Treatment of Wheat Straw on Site and Extent of Digestion by Lambs

Summary Two lamb trials were conducted to determine the effects of particle length (PL; 2.5 vs 10 cm) and sodium hydroxide (NaOH) treatment (0 vs 4%) of wheat straw on dry matter (DM) intake and site and extent of DM and neutral detergent fiber (NDF) digestion. Lambs in the first trial were fed ad libitum once daily. Lambs in the second trail were fed four times/d at 6-h intervals and were sacrificed after 7 d of fecal collection to determine site of digestion. For both trials, NaOH increased (P .10), lambs fed 2.5-cm, NaOH-treated straw appeared to have a greater percentage of total NDF digestion occurring postruminally than lambs fed untreated straw, suggesting an increased flow of potentially digestible fiber to the hindgut. This is supported by a shorter ruminal retention time of digesta in lambs fed the 2.5-cm, NaOHtreated straw. Ruminal volatile fatty acid concentrations were greater for NaOH-treated straw diets, which reflect the site of digestion results. Results of the present study suggest

Conference on Electrical Insulation and Dielectric Phenomena

The influence of conducting particles on the corona onset voltage and the breakdown voltage in a uniform field gap under ac voltage superimposed with iiegativc dc biasing voltage is investigated. The effect of particle length, gap spacing and the dc biasing voltage 011 the corona onset and tlie breakdown voltages is also presented and discussed. The breakdown voltage of different gap spacing and dc biasing voltage is compared with calculated values. The comparison shows good agreement between experimental and calculated values.