The approach is to obtain measurements that will permit comparisons of temporal evolution of bottom stress, suspended particle size, and optical and acoustical properties in the bottom boundary layer. The instrumentation is mounted on bottom tripods and an I-beam frame. The “OASIS” tripod includes a 9wavelength optical attenuation and absorption meter (WetLabs ac-9, with automated dissolved mea...

Commercial aerodynamic particle sizing instruments generally achieve the desired particle size measurement by accelerating a sample airstream in which the particles are suspended and measuring the velocity acquired by individual particles. The accelerating flow regime can cause liquid droplets to deform and this subsequently introduces errors. In this paper, we present an apparatus that enables...

A novel spectral transmittance approach for measuring the extinction coefficient of magnetic fluids is proposed. The measuring principle and accuracy of the approach are analysed. Experiments are conducted to measure the extinction coefficient of magnetic fluids with different particle volume fractions. The relative uncertainty of experimental data is less than 1.8%. The experimental results in...

The application of an electric field to a suspension of charged particles can lead to the formation of patterns due to electrohydrodynamic instabilities which remain poorly understood. We elucidate this behavior by visualizing the dynamics of charged carbon black particles suspended in a nonpolar solvent in response to an electric field. As the particles are transported across a microfluidic ch...

The diverse character of fluvial sediments makes the choice of laboratory analysis somewhat arbitrary and the pressing of sediment samples difficult. This report presents some theories and methods used by the Water Resources Division for analysis of fluvial sediments to determine the concentration of suspendedsediment samples and the particle-size distribution of both suspended-sediment and bed...

The inability to capture the physics of solid-particle suspension in turbulent fluid flow is holding back application of multiphase computational fluid dynamics techniques to the many problems involving particle suspension in nature and society. We present a theory for particle suspension capacity near no-slip frictional boundaries of turbulent flows. The suspension capacity parameter Γ include...

Particles suspended in turbulent flows are affected by the turbulence and at the same time act back on the flow. The resulting coupling can give rise to rich variability in their dynamics. Here we report experimental results from an investigation of finite-sized buoyant spheres in turbulence. We find that even a marginal reduction in the particle's density from that of the fluid can result in s...

Preliminary investigation on the feasibility of size selective passive sampling for atmospheric particles was undertaken through laboratory simulated and outdoor sampling. The passive samplers used in the research were improved from passive sampler used for sampling atmospheric organic contaminants. Sampled particle size distribution was analyzed by MasterSizer 2000 laser particle size analyzer...

Concentrated suspensions may shear thin when the suspended particles form planar sheets that slide over one another with less friction than if the particles are randomly distributed. In a naive model the suspension is described by a mean effective viscosity and particles that collide with each other redistribute the mean density in the shearing direction. This leads to a diffusion equation for ...

The primary objective of this paper is to describe the most common methods used to measure (i.e., sample and analyze) total suspended solids (TSS) and associated metals and phosphorus in urban runoff and to identify issues that may influence the accuracy of the results. This paper also discusses the availability of particle size distribution data from different developed and developing areas of...