Bulk Solids Characterization

The classical cyclone cut size model assumes discrete, non-agglomerating particles. Cohesive or moisture-sensitive fines can travel through a cyclone as agglomerates instead, which changes what a PSD result actually tells you about classifier performance.

Hausner ratio, shear cell, and dynamic flow energy results on the same PBF powder lot rarely agree exactly. That disagreement is a decision input, not proof that a method or lab got it wrong.

Wood powder can bridge because fibrous particles mechanically interlock, because moisture increases [...]

Jet milling micronization reduces particle size through particle-particle impact controlled by classifier wheel speed and feed rate. Pushing the cut point lower can raise amorphous surface content and hygroscopicity in ways a passing PSD result will not reveal. This guide covers the mechanism and the tests that actually diagnose a changed lot.

DEM input parameters are fitted to match a bulk observable, not derived from first principles. A parameter set calibrated against an angle of repose test constrains one point in a multi-dimensional parameter space. When the hopper geometry changes, the stress state changes, and unconstrained parameters become the dominant source of prediction error.

Bulk-blended fertilizer fails in three recurring ways: segregation between straight materials of different size and density, hygroscopic caking in urea and ammonium nitrate under humidity cycling, and dust release during bagging. Each failure mode maps to a specific diagnostic test rather than a single generic powder check.

LED-based particle image velocimetry (PIV) images the velocity field inside a moving powder bed during blending, adding spatial resolution that static angle of repose, Hausner ratio, and shear cell tests cannot provide. Here is what that resolution can and cannot support for a process decision.

Vacuum conveying contains by default: any breach draws air inward rather than pushing powder out. That containment advantage comes with a fixed pressure budget, and filter design competes directly with conveying velocity for every millibar of available driving force.

Co-processing engineers particle morphology, density, and surface structure into a single composite excipient particle. Flow function and compactibility testing show what that buys formulators on continuous direct compression lines, and where it does not.

Jenike shear cells and ring shear testers measure the same yield locus through different mechanics. Here is how their sample, stress range, and time differences map onto the mass-flow versus funnel-flow hopper design decision, plus a checklist for choosing between them.

Copper reflects most near-infrared laser light and conducts absorbed heat away faster than almost any other engineering metal. GRCop-42's move into commercial powder catalogs shows how feedstock morphology, oxide content, and particle size distribution are being engineered around that problem rather than worked around it.

A Pharmaceutical Research study trained Random Forest and XGBoost classifiers on particle size, shape, surface energy, and silica dry-coating data to predict powder blend flowability category. The accuracy holds up as a screening tool and breaks down in specific, predictable places.