Humidity Effects and Aging Behavior in Granular Media

1998 ◽  
Vol 543 ◽  
Author(s):  
F. Restagno ◽  
H. Gayvallet ◽  
L. Bocquet ◽  
E. Charlaix
Keyword(s):  
Relative Humidity ◽  
Granular Medium ◽  
Granular Media ◽  
Capillary Condensation ◽  
Glass Beads ◽  
Aging Behavior ◽  
Humidity Effects ◽  
Small Glass ◽  
Aging Properties ◽  
Maximum Stability

AbstractWe present a study of humidity effects on the maximum stability angle in granular media. We show that a granular medium of small glass beads exhibits aging properties: the first avalanche angle increases logarithmically with the resting time of the pile. This aging behavior is found to depend on the relative humidity of the surrounding atmosphere. A short interpretation of this effect, based on a model of activated capillary condensation, is proposed.

Humidity-Induced Cohesion Effects in Granular Media

2000 ◽  
Vol 627 ◽  
Author(s):  
Nathalie Fraysse ◽  
Luc Petit
Keyword(s):  
Granular Medium ◽  
Granular Media ◽  
Global Scale ◽  
Interparticle Forces ◽  
Wetting Properties ◽  
Small Glass ◽  
Capillary Bridges ◽  
Scale Properties ◽  
Comparison Of The Results ◽  
Maximal Stability

ABSTRACTExperiments were performed under accurately-controlled humidity conditions in order to quantify effects induced by humidity on granular materials. Measurements of the maximal stability angle of a pile made of small glass beads are reported as a function of the relative vapor pressure in the cell, up to close to saturation. The comparison of the results obtained with fluids differing in their molecular interactions with glass, namely water and heptane, shows that the wetting properties of the interstitial liquid on the grains have a strong influence on the cohesion of the non-saturated granular medium. This suggests that gravimetric experiments which could indirectly give information on the size of the capillary bridges that form between grains should be useful to understand the close connection that exists, through interparticle forces, between microscopic properties such as wetting properties and surface roughness of the grains, and global-scale properties of the pile, as its stability and flowability.

A Low-Frequency Forced Torsion Pendulum for the Measurement of the Mechanical Properties of Granular Media

2000 ◽  
Vol 627 ◽  
Author(s):  
G. D'Anna
Keyword(s):  
Mechanical Properties ◽  
Granular Media ◽  
Low Frequency ◽  
Glass Beads ◽  
Torsion Pendulum ◽  
Dynamic Moduli ◽  
Small Glass ◽  
Static Mechanical ◽  
Macroscopic Failure ◽  
Static Mechanical Properties

ABSTRACTWe present a forced torsion pendulum designed to measure the dynamic moduli of granular media. In the method, the oscillating probe of the pendulum is immersed into various materials, such as sand, glass beads, snow. The apparatus operates at low-frequency and provides information about the quasi-static mechanical properties of the medium. In particular, a peak in the losses is ascribed to friction and cohesion between the grains, and a measure of the macroscopic failure limit can be obtained. As an example the effect of moisture-induced ageing in small glass beads, and the effect of sintering of ice grains in snow, are shown.

Penetration of spheres into loose granular media

2004 ◽  
Vol 82 (6) ◽  
pp. 439-446 ◽  
Author(s):  
J R de Bruyn ◽  
A M Walsh
Keyword(s):  
Yield Stress ◽  
Penetration Depth ◽  
Newtonian Fluid ◽  
Granular Medium ◽  
Effective Viscosity ◽  
Granular Media ◽  
Experimental Results ◽  
Incident Momentum ◽  
Small Glass ◽  
Zero Momentum

We study the penetration of steel spheres dropped vertically into a container of loosely packed, small glass beads. We find that the penetration depth of the spheres increases linearly with the incident momentum of the projectile, but with a zero-momentum intercept that can be either positive or negative. This behavior can be understood by modelling the granular medium as a non-Newtonian fluid with a yield stress and an effective viscosity. We derive the scaling behavior of the viscosity and find agreement with our experimental results. PACS Nos.: 45.70.–n, 83.80.Fg, 47.50.+d

scholarly journals Relative Humidity Effects on Tolerance of the Kuruma Prawn Exposed to 14°C Air

1997 ◽  
Vol 63 (2) ◽  
pp. 194-198
Author(s):  
Maher Samet ◽  
Kaworu Nakamura
Keyword(s):  
Relative Humidity ◽  
Humidity Effects

scholarly journals Under pressure: Hydrogel swelling in a granular medium

2021 ◽  
Vol 7 (7) ◽  
pp. eabd2711
Author(s):  
Jean-François Louf ◽  
Nancy B. Lu ◽  
Margaret G. O’Connell ◽  
H. Jeremy Cho ◽  
Sujit S. Datta
Keyword(s):  
Oil Recovery ◽  
Granular Medium ◽  
Granular Media ◽  
Three Dimensional ◽  
Osmotic Swelling ◽  
Widespread Adoption ◽  
Dry Soil ◽  
Hydrogel Swelling

Hydrogels hold promise in agriculture as reservoirs of water in dry soil, potentially alleviating the burden of irrigation. However, confinement in soil can markedly reduce the ability of hydrogels to absorb water and swell, limiting their widespread adoption. Unfortunately, the underlying reason remains unknown. By directly visualizing the swelling of hydrogels confined in three-dimensional granular media, we demonstrate that the extent of hydrogel swelling is determined by the competition between the force exerted by the hydrogel due to osmotic swelling and the confining force transmitted by the surrounding grains. Furthermore, the medium can itself be restructured by hydrogel swelling, as set by the balance between the osmotic swelling force, the confining force, and intergrain friction. Together, our results provide quantitative principles to predict how hydrogels behave in confinement, potentially improving their use in agriculture as well as informing other applications such as oil recovery, construction, mechanobiology, and filtration.

Study on the Aging Rules of Rigid Polyurethane Foams at Indoor Storage and Different Hygrothermal Conditions

2005 ◽  
Vol 24 (4) ◽  
pp. 197-208 ◽  
Author(s):  
Yuan-Jun Liu ◽  
Wen Zhai ◽  
Chuan-Lan He ◽  
Jian-Guo Deng ◽  
Ke-Jian Ji ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Aging Time ◽  
Fire Retardant ◽  
Ester Group ◽  
Polyurethane Foams ◽  
Compressive Modulus ◽  
Glass Beads ◽  
Hygrothermal Aging ◽  
Aging Properties ◽  
Mass Dimension

The aging rules of rigid polyurethane foam (PUR) at indoor storage and different hygrothermal conditions have been studied. Four parameters, which are mass, dimension, compressive strength and compressive modulus were tested. At indoor storage, mass, dimension and compressive strength vary slowly with an increase in aging time, while compressive modulus decreases quickly. PUR is sensitive to relative humidity (RH) verified by accelerated hygrothermal aging, and hydrolysis of ester group is the main reason resulting in the decrease of compressive properties. The filling with fire retardant and glass beads had some effect on hygrothermal aging properties of PUR. The addition of fire retardant increased compressive strength with aging time in the total trend, but it made dimension stability worse. The addition of glass beads slightly improved hygrothermal aging properties.

Computational modeling of temperature and relative humidity effects on concrete expansion due to alkali-silica reaction

2021 ◽  
pp. 104237
Author(s):  
Lifu Yang ◽  
Madura Pathirage ◽  
Huaizhi Su ◽  
Mohammed Alnaggar ◽  
Giovanni Di Luzio ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Computational Modeling ◽  
Alkali Silica Reaction ◽  
Humidity Effects

GRANULAR MEDIA ON A VIBRATING PLATE: A MOLECULAR DYNAMICS SIMULATION

1993 ◽  
Vol 07 (09n10) ◽  
pp. 1779-1788 ◽  
Author(s):  
JASON A.C. GALLAS ◽  
HANS J. HERRMANN ◽  
STEFAN SOKOLOWSKI
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Granular Materials ◽  
Granular Medium ◽  
Granular Media ◽  
Dynamics Simulation ◽  
Dissipation Of Energy ◽  
Conveyor Belts ◽  
Good Agreement ◽  
Vibrating Plate

When sand or other granular materials are shaken, poured or sheared many intriguing phenomena can be observed. We will model the granular medium by a packing of elastic spheres and simulate it via Molecular Dynamics. Dissipation of energy and shear friction at collisions are included. The onset of fluidization can be determined and is in good agreement with experiments. On a vibrating plate we observe the formation of convection cells due to walls or amplitude modulations. Density and velocity profiles on conveyor belts are measured and the influence of an obstacle discussed. We mention various types of rheology for flow down an inclined chute or through a pipe and outflowing containers.

Sign in / Sign up

Export Citation Format

Share Document