The dependence of janssen effect screening length on the mass concentration of bidisperse granular material column.

Date

4-2012

Degree

Bachelor of Science in Applied Physics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Junius Andre F. Balista

Abstract

Janssen effect is a phenomenon where the apparent total mass or the mass measured at the bottom of a container is not equal to the mass of granular material poured into the container. The rate of change in the apparent mass as a function of height decreases as more granular material is poured into the tube, characterized by an exponential decay. The decay constant, known as the screening length, is a measure of the range of interaction of a grain with the other grains, with the wall or with the bottom of the container. Previous studies did not consider the effect of mass concentration on the screening length. Here, the mass concentration of a bidisperse (big and small grains) granular material was varied (0%, 25%, 50%, 75%, and 100% small grains) and the corresponding screening length was determined for six trials per concentration. The results show that the varying mass concentrations determine the range of interaction among grains. Except for some exceptions yet to be explained, apparently the effective screening length is a weighted sum of the screening lengths of the monodisperse cases. The dependence of screening length to mass concentration has implications on granular mixing and segregation models.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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