The toxicity of an acid mine drainage (AMD) mixing zone was investigated by placing bluegill (Lepomis macrochirus) at the confluence of a stream contaminated by AMD and a stream having neutral pH. A mixing channel receiving water from both streams was assembled in the field, during July and October 1996, to determine the toxicity of freshly mixed and aged water (2.9-7.5 min). The AMD stream had...

A Laser Induced Fluorescence technique (LIF) has been used to study the mixing behavior of two emerging streams in a T-Type mixing chamber. A mixing index on the basis of digital image light intensities is calculated. It has been shown that averaging over more than 800 images leads to a stable mixing index calculation. Moreover, the effect of equal and un-equal flow rates on the mixing behavior...

The solar convection zone exhibits a strong level of differential rotation, whereby the rotation period of the polar regions is about 25-30% longer than the equatorial regions. The Coriolis force associated with these zonal flows perpetually “pumps” the convection zone fluid, and maintains a quasi-steady circulation, poleward near the surface. What is the influence of this meridional circulatio...

[1] The mixing zone between freshwater and seawater in a coastal aquifer is an important transition region that controls regional groundwater flow dynamics and reactive transport processes. While experimental procedures have been developed to study the movement of salt wedges in aquifers, so far no one has attempted to exclusivelymap themixing zone associated with the wedge in a laboratory-scal...

The US Environmental Protection Agency has a history of developing plume models and providing technical assistance. The Visual Plumes model (VP) is a recent addition to the public-domain models available on the EPA Center for Exposure Assessment Modeling (CEAM) web page. The Windows-based VP adapts, modifies, and enhances the earlier DOS-based PLUMES with a new interface, models, and capabiliti...

As part of our project entitled Wind, Waves, and Mixing in the Coastal Region (AO3-379) some measurements of waves and current profiles were performed in our study site. In the Pacific coast of Baja California, a wave and current sensor, a marine radar and a meteorological station have been in operation since mid 1998. Additionaly, a current meter profiler (adp) was installed for some days in e...

Environmental transitions often result in resource mixtures that overcome limitations to microbial metabolism, resulting in biogeochemical hotspots and moments. Riverine systems, where groundwater mixes with surface water (the hyporheic zone), are spatially complex and temporally dynamic, making development of predictive models challenging. Spatial and temporal variations in hyporheic zone micr...

BACKGROUND Gun pressurization in total knee arthroplasty (TKA) may result in better cement penetration than hand packing, leading to fewer tibial plate failures. We compared cement intrusion characteristics between vacuum mixing and gun pressurization versus hand mixing and packing in the proximal tibia among patients undergoing TKA. METHODS We analyzed 6-week radiographs from 77 consecutive ...

When the frequencies of a pair of collinear shear and longitudinal waves satisfy the resonant condition, mixing of these two primary waves generates a third, resonant shear wave that propagates in the direction opposite to the propagating direction of the primary shear wave. In this study, experiments were conducted to demonstrate that the acoustic nonlinearity parameter at the location of the ...

The inversion of helioseismic modes leads to the sound velocity inside the Sun with a precision of about 0.1 per cent. Comparisons of solar models with the "seismic sun" represent powerful tools to test the physics: depth of the convection zone, equation of state, opacities, element diffusion processes and mixing inside the radiative zone. We now have evidence that microscopic diffusion (elemen...