We investigated the transport and retention kinetics of silica encapsulated – core double stranded DNA particles (SiDNASi) through 15 cm saturated quartz sand columns as a function wide range colloid injection concentrations (C0 = 8.7 ×102 - 6.6 ×108 ml?1). The breakthrough curves (BTCs) exhibited an overall 2-log increase maximum relative effluent concentration with increasing C0. Inverse curv...

Porous media column experiments were used to investigate Pseudomonas fluorescens strain P17 transport as a function of water content and the influences of the solid–liquid and gas–liquid interfaces. Retention of radiolabeled P17 in washed quartz sand was evaluated at 100, 84, and 46% water saturation. At the completion of each experiment, the porous medium was extruded and sampled directly for ...

The role of extracellular macromolecules on Escherichia coli O157:H7 transport and retention was investigated in saturated porous media. To compare the relative transport and retention of E. coli cells that are macromolecule rich and deficient, macromolecules were partially cleaved using a proteolytic enzyme. Characterization of bacterial cell surfaces, cell aggregation, and experiments in a pa...

The influence of near-bed sorting processes on heavy mineral content in suspension is discussed. Sediment concentrations above a rippled bed of mixed quartz and heavy mineral sand were measured under regular nonbreaking waves in the laboratory. Using the traditional gradient diffusion process, settling velocity would be expected to strongly affect sediment distribution. This was not observed du...

Sand dripping in 1 dimensional Sand Pile Model is rst studied. Patterns and signals appear. Their behaviors and interactions are explained and asymptotic approximations are made. The total collapsing time of a single stack of sand is linear in function of the number of grains.

Soil reflectance signatures were modeled using the digital imaging and remote sensing image generation model and Blender three-dimensional (3-D) graphic design software. Using these tools, the geometry, radiometry, and chemistry of quartz and magnetite were exploited to model the presence of particle size and porosity effects in the visible and the shortwave infrared spectrum. Using the physics...

Silicon carbide is produced by heating a mixture of petroleum coke and silica sand to approximately 2000 degrees C in an electric furnace for 36 hours. During heating, large amounts of carbon monoxide are released, sulphur dioxide is produced from residual sulphur in the coke, and hydrocarbon fume is produced by pyrolysis of the coke. Loading and unloading furnaces causes exposures to respirabl...

Toxicity Summary: IDENTIFICATION: Bentonite is a rock formed of highly colloidal and plastic clays composed mainly of montmorillonite and produced in situ devitrification of volcanic ash. It may contain feldspar, cristobalite and crystaline quartz. Major uses of bentonite include binding foundry sand in molds, absorbing grease, oil and animal wastes; palletizing taconite iron ore and improving ...