A quantity of miscible contaminant gas is released into the atmospheric boundary layer and the objective is to describe the evolution of contaminant concentration values within the cloud. Although turbulent convective motions will spread the contaminant cloud over distances of tens of meters the only mixing between host and contaminant fluid, and hence reduction of concentration values, takes p...

For T > 0, fixed, let UT = U × 0,T where U denotes a bounded open set in Rn.Suppose that U is filled with a material in which a contaminant is being transported by various means including diffusion and convection. Let the concentration of contaminant at x, t in UT be denoted by ux, t and let the vector field F⃗x, t denote the flux field for the contaminant. Then we can state a conservati...

Polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzo-p-furans (PCDD/Fs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane diastereomers (HBCDs), and perfluorinated compounds (PFCs) were analyzed in popular farmed fish such as salmon, trout, tilapia, and pangasius and in farmed shrimp. The samples originated from southeas...

Subsequent to modeling of natural attenuation processes to predict contaminant trends and plume dynamics, monitoring data were used to evaluate the effectiveness of natural attenuation at reducing contaminant concentrations in groundwater at seven fuel-contaminated sites. Predicted and observed contaminant trends at seven sites were compared in order to empirically assess the accuracy of some f...

The mechanism of aqueous contaminant removal by elemental iron (Fe 0 ) materials (e.g., in Fe 0 -H2O systems) has been largely discussed in the “iron technology” literature. Two major removal mechanisms are usually discussed: (i) contaminant adsorption onto Fe 0 oxidation products, and (ii) contaminant reduction by Fe 0 , Fe II or H/H2. However, a closer inspection of the chemistry of the Fe 0 ...

: This paper presents cooperative path planning approach for multi UAVs to detect, model and track the shape of a contaminant cloud boundary. The objective of this research study is to manage the resources (airborne sensors) such as to determine the boundary of a cloud and track its motion with minimum information. The dispersing model of the contaminant cloud boundary is based on SCIPUFF. The ...

Heparin is a critically important anticoagulant drug that was contaminated with a persulfonated polysaccharide in 2008, resulting in a number of severe adverse reactions, some leading to death. Controversy remains as to the precise composition of the 2008 contaminant, and new information suggests that heparin may now be subject to adulteration with a new, difficult to detect, contaminant, N-sul...

The Advanced CCD Imaging Spectrometer (ACIS) on the Chandra X-ray Observatory is suffering a gradual loss of low energy sensitivity due to a buildup of a contaminant. High resolution spectra of bright astrophysical sources using the Chandra Low Energy Transmission Grating Spectrometer (LETGS) have been analyzed in order to determine the nature of the contaminant by measuring the absorption edge...

Contaminants in surface water entering karst aquifers in focused recharge can be transported rapidly through the system to discharge at springs. Such contaminants act as anthropogenic tracers of ground-water transport; analysis of their breakthrough curves as they discharge from springs allows identification and apportionment of contaminant sources, and can provide insight into aquifer structur...