We consider an upwinding covolume or control-volume method for a system of first order PDEs resulting from the mixed formulation of a convection-diffusion equation with a variable anisotropic diffusion tensor. The system can be used to model the steady state of the transport of a contaminant carried by a flow. We use the lowest order Raviart–Thomas space and show that the concentration and conc...

The influence of viscosity and surface tension on oxygen transfer was investigated using planar laser-induced fluorescence with inhibition (PLIF-I). the were modified Triton X-100 polyacrylamide, respectively. Changes in hydrodynamic parameters millimetric bubbles identified, calculated. results revealed a decrease mass transferred presence contaminant. For viscosity, allowed for by current cor...

High sensitivity methods such as next generation sequencing and polymerase chain reaction (PCR) are adversely impacted by organismal and DNA contaminants. Current methods for detecting contaminants in microbial materials (genomic DNA and cultures) are not sensitive enough and require either a known or culturable contaminant. Whole genome sequencing (WGS) is a promising approach for detecting co...

Recent years have seen considerable interest in sensor networks. In this paper we study networks of chemical or similar sensors detecting a plume of contaminant, such as that in Figure (i), although our analysis also applies to sensors of other kinds. In order to optimise power consumption, we assume that sensors are normally quiescent, but can “wake” each other if contaminant is detected. Cons...

Predicting the fate and movement of contaminant in soils and groundwater is essential to assess and reduce the risk of soil contamination and groundwater pollution. Reaction processes of contaminant often decreased monotonously with depth. Time-dependent input sources usually occurred at the inlet of natural or human-made system such as radioactive waste disposal site. This study presented a on...

the sources of groundwater pollution such as, industrial effluents, sewage and extensive farming have lead to agrochemical pollution. mathematical modeling helps to analyze the existing situation, allows forecasting, and to evaluate the effects of changes in the surrounding water quality. the present research has been focused mainly towards understanding the various processes affecting the tran...

The following explores the issue of how reductions in contaminant loading to plumes will effect downgradient water quality. An idealized scenario of two adjacent layers of uniform geologic media, one transmissive and the other low permeability, is considered. A high concentration source, similar to a thin DNAPL pool, is introduced in the transmissive layer immediately above the low permeability...

Passive sampling methods (PSMs) allow the quantification of the freely dissolved concentration (Cfree ) of an organic contaminant even in complex matrices such as sediments. Cfree is directly related to a contaminant's chemical activity, which drives spontaneous processes including diffusive uptake into benthic organisms and exchange with the overlying water column. Consequently, Cfree provides...

This experiment was conducted to determine how much contaminant could be expected to be inhaled when overbreathing several different types of respirators. These included several tight-fitting and loose-fitting powered air-purifying respirators (PAPRs) and one air-purifying respirator (APR). CO(2) was used as a tracer gas in the ambient air, and several loose-and tight-fitting respirators were t...

Laboratory scale experiments were performed to evaluate the feasibility of biofilters for the removal of H 2 S from wastewater treatment plant waste air. The effects of changes in air flow rate and contaminant concentration on biofilter performance treating H 2 S odours were also assessed. Compost was used as media in biofilter. The study was carried out in six different phases, by increasing H...