The ultimate limitations to the performance of long-range sonar are due to ocean sound speed perturbations and the characteristics of the ambient acoustic noise field. Scattering and diffraction resulting from internal waves and other ocean processes limit the temporal and spatial coherence of the received signal, while the ambient noise field is in direct competition with the received signal. ...

The effects of loading and aging pyrene in soils in the presence of four environmentally common nonaqueous-phase liquids (NAPLs) (hexadecane, 2,2,4,4,6,8,8-heptamethylnonane [HMN], toluene, and dimethyl phthalate [DMP]) on its subsequent desorption from those soils, earthworm accumulation, biodegradation, and extractability were tested by using two dissimilar soils. The presence of each of the ...

Upon their release into the subsurface, non-aqueous phase liquids (NAPLs) dissolve slowly in groundwater and/or volatilize in the vadose zone threatening the environment and public health over extended periods of time. The failure of a treatment technology at any given site is often due to the unnoticed presence of dissolved NAPL trapped in low permeability areas and/or the remaining presence o...

725 Chlorinated solvents in the form of DNAPLs exist at a large number of hazardous waste sites. The distribution of DNAPLs is controlled by fi ngering (Held and Illangasekare, 1995), preferential channeling, and heterogeneity of the subsurface formation (Kueper and Frind, 1991). All of these factors increase the complexity of NAPL movement and subsequent entrapment (Schwille, 1988; Kueper et a...

At sites where aqueous film forming foams (AFFFs) are used for fire suppression or training activities, interactions between dissolved foam constituents and organic liquids could alter contaminant migration in the subsurface. In this study, batch reactor column experiments were conducted to investigate potential AFFF solutions enhance solubility mobility of three representative non-aqueous phas...

Chloroethenes like tetrachloroethene (PCE) are the most prevalent groundwater contaminants in the USA. Their presence as nonaqueous phase liquids (NAPLs) makes remediation difficult. Among options for NAPL cleanup, co-solvent injection has demonstrated success. However, the process has the potential to leave considerable residue of the co-solvent as well as residual chloroethene. Our rationale ...

Dissolution of a trapped non-aqueous phase liquid (NAPL) in soils and aquifers is a matter of great interest for the remediation of contaminated geological structures. In this work, the Volume Averaging Method is used to upscale the ``active dispersion'' phenomenon, taking into account both dispersion and dissolution of the NAPL. The method provides a macroscopic equation involving a dispersion...