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Articles 1 - 5 of 5
Full-Text Articles in Physical Sciences and Mathematics
A New Model For The Spectral Induced Polarization Signature Of Bacterial Growth In Porous Media, Andre Revil, Estella A. Atekwana, C. Zhang, Abderrahim Jardani, Schaun M. Smith
A New Model For The Spectral Induced Polarization Signature Of Bacterial Growth In Porous Media, Andre Revil, Estella A. Atekwana, C. Zhang, Abderrahim Jardani, Schaun M. Smith
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
The complex conductivity of porous materials and colloidal suspensions comprises two components: an in-phase conductivity associated with electromigration of the charge carriers and a quadrature conductivity associated with the reversible storage of the charges at some polarization length scales. We developed a quantitative model to investigate the frequency domain induced polarization response of suspensions of bacteria and bacteria growth in porous media. Induced polarization of bacteria (α polarization) is related to the properties of the electrical double layer of the bacteria. Surface conductivity and α polarization are due to the Stern layer of counterions occurring in a brush of polymers …
Sensitivity Of Geoelectrical Measurements To The Presence Of Bacteria In Porous Media, Gamal Z. Abdel Aal, Estella A. Atekwana, Silvia Rossbach, D. Dale Werkema
Sensitivity Of Geoelectrical Measurements To The Presence Of Bacteria In Porous Media, Gamal Z. Abdel Aal, Estella A. Atekwana, Silvia Rossbach, D. Dale Werkema
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
We investigated the sensitivity of low-frequency electrical measurements (0.1-1000 Hz) to (1) microbial cell density, (2) live and dead cells, and (3) microbial attachment onto mineral surfaces of clean quartz sands and iron oxide-coated sands. Three strains of Pseudomonas aeruginosa PAO1 (wild type and rhlA and pilA mutant) with different motility and attachment properties were used. Varying concentrations of both live and dead cells of P. aeruginosa wild type in sand columns showed no effect on the real conductivity component (σ′). However, the imaginary conductivity component (σ″) increased linearly with increasing concentrations of live cells in sand columns, whereas minimal …
Effect Of Bacterial Adsorption On Low Frequency Electrical Properties Of Clean Quartz Sands And Iron-Oxide Coated Sands, Gamal Z. Abdel Aal, Estella A. Atekwana, Sylvia Radzikowski, Silvia Rossbach
Effect Of Bacterial Adsorption On Low Frequency Electrical Properties Of Clean Quartz Sands And Iron-Oxide Coated Sands, Gamal Z. Abdel Aal, Estella A. Atekwana, Sylvia Radzikowski, Silvia Rossbach
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Low frequency electrical measurements (0.1-1000 Hz) were conducted to investigate the adsorption effect of Pseudomonas aeruginosa cells onto clean quartz sands and iron-oxide coated sands. The clean quartz sands showed a gradual increase in the microbial adsorption to mineral grains, concurrent with an increase of 13% in the imaginary conductivity component (σ″). However, iron-oxide coated sands (20-100% by weight) showed a rapid increase in microbial adsorption with σ″ reaching a maximum of 37% for the 80-100% iron coated sands. No significant changes were observed in the real conductivity component (σ′) due to microbial adsorption. A power law dependency was observed …
Microbial Nanowires: Is The Subsurface "Hardwired"?, Dimitrios Ntarlagiannis, Estella A. Atekwana, Eric A. Hill, Yuri A. Gorby
Microbial Nanowires: Is The Subsurface "Hardwired"?, Dimitrios Ntarlagiannis, Estella A. Atekwana, Eric A. Hill, Yuri A. Gorby
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
The Earth's shallow subsurface results from integrated biological, geochemical, and physical processes. Methods are sought to remotely assess these interactive processes, especially those catalysed by micro-organisms. Using saturated sand columns and the metal reducing bacterium Shewanella oneidensis MR-1, we show that electrically conductive appendages called bacterial nanowires are directly associated with electrical potentials. No significant electrical potentials were detectable in columns inoculated with mutant strains that produced non-conductive appendages. Scanning electron microscopy imaging revealed a network of nanowires linking cells-cells and cells to mineral surfaces, "hardwiring" the entire length of the column. We hypothesize that the nanowires serve as conduits …
In-Situ Apparent Conductivity Measurements And Microbial Population Distribution At A Hydrocarbon-Contaminated Site, Estella A. Atekwana, D. Dale Werkema, Joseph W. Duris, Silvia Rossbach, Eliot A. Atekwana, William A. Sauck, Daniel P. Cassidy, Jay Means, Franklyn D. Legall
In-Situ Apparent Conductivity Measurements And Microbial Population Distribution At A Hydrocarbon-Contaminated Site, Estella A. Atekwana, D. Dale Werkema, Joseph W. Duris, Silvia Rossbach, Eliot A. Atekwana, William A. Sauck, Daniel P. Cassidy, Jay Means, Franklyn D. Legall
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
We investigated the bulk electrical conductivity and microbial population distribution in sediments at a site contaminated with light nonaqueous-phase liquid (LNAPL). The bulk conductivity was measured using in-situ vertical resistivity probes; the most probable number method was used to characterize the spatial distribution of aerobic heterotrophic and oil-degrading microbial populations. The purpose of this study was to assess if high conductivity observed at aged LNAPL-impacted sites may be related to microbial degradation of LNAPL. The results show higher bulk conductivity coincident with LNAPL-impacted zones, in contrast to geoelectrical models that predict lower conductivity in such zones. The highest bulk conductivity …