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Articles 1 - 10 of 10
Full-Text Articles in Physical Sciences and Mathematics
Hydrological Monitoring With Hybrid Sensor Networks, Thomas V. Freiberger, Sahra Sedigh, Estella A. Atekwana
Hydrological Monitoring With Hybrid Sensor Networks, Thomas V. Freiberger, Sahra Sedigh, Estella A. Atekwana
Electrical and Computer Engineering Faculty Research & Creative Works
Existing hydrological monitoring systems suffer from short- comings in accuracy, resolution, and scalability. Their fragility, high power consumption, and lack of autonomy necessitate frequent site visits. Cabling requirements and large size limit their scalability and make them prohibitively expensive. The research described in this paper proposes to alleviate these problems by pairing high-resolution in situ measure- ment with remote data collection and software maintenance. A hybrid sensor network composed of wired and wireless connections autonomously measures various attributes of the soil, including moisture, temperature, and resistivity. The mea- surements are communicated to a processing server over the existing GSM cellular …
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 …
Blue Nile Incision On The Ethiopian Plateau: Pulsed Plateau Growth, Pliocene Uplift, And Hominin Evolution, Nahid D.S. Gani, M. Royhan Gani, Mohamed G. Abdel Salam
Blue Nile Incision On The Ethiopian Plateau: Pulsed Plateau Growth, Pliocene Uplift, And Hominin Evolution, Nahid D.S. Gani, M. Royhan Gani, Mohamed G. Abdel Salam
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
The 1.6-km-deep Gorge of the Nile, a rival of the Grand Canyon, resulted from the deep incision of the Blue Nile drainage into the uplifted Ethiopian Plateau. Understanding the incision history of the plateau is crucial to unraveling the Cenozoic tectonoclimatic evolution of the region, particularly because the region has long been used as a natural laboratory to understand the geodynamics of continental rifting and the evolution of hominins. We undertake a quantitative geomorphologic approach integrating field, geographic information system (GIS), and digital elevation model (DEM) data to analyze incision (volume, long-term rates, and spatiotemporal variability) and river longitudinal profiles …
The Microbial Community Structure In Petroleum-Contaminated Sediments Corresponds To Geophysical Signatures, Jonathan P. Allen, Estella A. Atekwana, Eliot A. Atekwana, Joseph W. Duris, D. Dale Werkema, Silvia Rossbach
The Microbial Community Structure In Petroleum-Contaminated Sediments Corresponds To Geophysical Signatures, Jonathan P. Allen, Estella A. Atekwana, Eliot A. Atekwana, Joseph W. Duris, D. Dale Werkema, Silvia Rossbach
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
The interdependence between geoelectrical signatures at underground petroleum plumes and the structures of subsurface microbial communities was investigated. For sediments contaminated with light non-aqueous-phase liquids, anomalous high conductivity values have been observed. Vertical changes in the geoelectrical properties of the sediments were concomitant with significant changes in the microbial community structures as determined by the construction and evaluation of 16S rRNA gene libraries. DNA sequencing of clones from four 16S rRNA gene libraries from different depths of a contaminated field site and two libraries from an uncontaminated background site revealed spatial heterogeneity in the microbial community structures. Correspondence analysis showed …
Sedimentology Of Acid Saline Lakes In Southern Western Australia: Newly Described Processes And Products Of An Extreme Environment, Kathleen Counter Benison, Brenda Beitler Bowen, Francisca Oboh-Ikuenobe, Elliot A. Jagniecki, Deidre A. Laclair, Stacy L. Story, Melanie R. Mormile, Boyoung Hong
Sedimentology Of Acid Saline Lakes In Southern Western Australia: Newly Described Processes And Products Of An Extreme Environment, Kathleen Counter Benison, Brenda Beitler Bowen, Francisca Oboh-Ikuenobe, Elliot A. Jagniecki, Deidre A. Laclair, Stacy L. Story, Melanie R. Mormile, Boyoung Hong
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Naturally acid saline systems with pH values between 1.7 and 4 are common on the Yilgarn Craton of southern Western Australia. a combination of physical and chemical processes here yield a previously undescribed type of modern sedimentary environment. Flooding, evapoconcentration, desiccation, and eolian transport at the surface, as well as influx of acid saline groundwaters, strongly influence these lakes. Halite, gypsum, kaolinite, and iron oxides precipitate from acid hypersaline lake waters. Shallow acid saline groundwaters affect the sediments of the lakes and associated mudflats, sandflats, channels, and dunes by precipitating early diagenetic halite, gypsum, iron oxides, clays, jarosite, and alunite. …
Extinction Pattern Of Reef Ecosystems In Latest Permian, Yasheng Wu, Jiasong Fan, Hongxia Jiang, Wan Yang
Extinction Pattern Of Reef Ecosystems In Latest Permian, Yasheng Wu, Jiasong Fan, Hongxia Jiang, Wan Yang
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Studies of two Permian-Triassic boundary (PTB) sections on top of a Changhsingian reef in Ziyun, Guizhou Province, southwestern China indicate that the end-Permian mass extinction of reef ecosystems occurred in two steps. The first step is the extinction of all stenotropic organisms such as calcisponges and fusulinids in the latest Permian (in the Clarkina yini conodont zone). The biota after the first extinction is simple, comprising eurytropic organisms including microgastropods, ostracods, and some small burrowing organisms, or only algal mats. At the beginning of the Early Triassic (i.e. the beginning of the Hindeodus parvus zone), the environments became anoxic, and …
Percussive Penetration Of Unconsolidated Granular Media In A Laboratory Setting, Leslie S. Gertsch
Percussive Penetration Of Unconsolidated Granular Media In A Laboratory Setting, Leslie S. Gertsch
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
This controlled study examined the feasibility of a simple percussive approach to drilling through unconsolidated regolith deposits on Mars. The experiments showed that the approach is feasible at the low power levels and low confining pressures used, and that the rate of impact is more important to the penetration rate than is the mass of the impactor (hammer). More massive impactors tend to lower energy efficiency, as they do in terrestrial pile-driving. Unexpectedly, penetration plotted against applied energy tends to cluster into parallel linear trends. Within a given cluster, penetration is very sensitive to applied energy, while between clusters, the …
Impacts Of Acid Mine Drainage On Carbon Cycling In Receiving Streams, Ernest W. Fonyuy
Impacts Of Acid Mine Drainage On Carbon Cycling In Receiving Streams, Ernest W. Fonyuy
Doctoral Dissertations
"Field and laboratory investigations of acid mine drainage (AMD) contaminated and uncontaminated waters were conducted in order to determine and model processes and reaction mechanisms that control dissolved inorganic carbon (DIC) transformation and shifts in isotope ratio of DIC (Δ¹³CDIC). The results show that AMD caused variable pH changes, overall decreases in Fe²⁺, alkalinity, and DIC, and increases in (Δ¹³CDIC) in receiving streams. AMD caused more than 50 to > 98% seasonal DIC loss in stream water through CO₂ degassing. High DIC losses corresponded to high Fe²⁺ and lower or no HCO₃⁻ in the water samples, because …
An Investigation Of Lead And Other Metal Contaminants In The Sediments Of Clearwater Lake, Missouri, Gary W. Krizanich
An Investigation Of Lead And Other Metal Contaminants In The Sediments Of Clearwater Lake, Missouri, Gary W. Krizanich
Doctoral Dissertations
"The purpose of this investigation is to characterize the spatial and temporal distribution and concentration of trace metals in sediments of Clearwater Lake. Understanding how trace metals are released to and transported in aquatic environments is important to the overall understanding of the impacts of mining on the natural environment. The main focus of this research will be on historic sedimentation within Clearwater Lake, which may act as a sink where mining related trace metals are stored. Because of their high preservation rates in basins, sediments can provide detailed chronostratigraphic histories of trace metal inputs in lakes. Sediment records can …
Incipient Continental Rifting: Insights From The Okavango Rift Zone, Northwestern Botswana, Baraka D. Kinabo
Incipient Continental Rifting: Insights From The Okavango Rift Zone, Northwestern Botswana, Baraka D. Kinabo
Doctoral Dissertations
"In this dissertation aeromagnetic, gravity, and Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) data from the Okavango Rift Zone in northwest Botswana are used to map the distribution of rift and basement structures. The distribution of these structures provide useful insights into the early stages of continental rifting. The objectives of this study are (1) assessing the role of pre-existing structures on rift basin development, (2) characterizing the geometry of the nascent rift basins, (3) documenting fault growth and propagation patterns, and (4) investigating the border fault development"--Abstract, page iv.