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Design Of An Implant For First Metatarsophalangeal Joint Hemiarthroplasty, Atul Kumar Jan 2011

Design Of An Implant For First Metatarsophalangeal Joint Hemiarthroplasty, Atul Kumar

ETD Archive

Osteoarthritis (OA) is the most common form of arthritis and it affects 27 million US adults. OA disease involves all of the tissues of the diarthrodial joint and ultimately, may lead to softening, ulceration, loss of articular cartilage, sclerosis and polished appearance of the subchondral bone, osteophytes, and subchondral cysts. The first metatarsophalangeal joint (MTPJ1) is affected in up to 42 cases of OA. Besides osteoarthritis, other conditions such as rheumatoid arthritis and gout also affect the MTPJ1. Involvement of MTPJ1 with these conditions invariably leads to deformed toe such as hallux valgus and hallux rigidus. Over 150 surgical techniques …

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Development Of A Muscle Force Optimization Algorithm To Improve Center Of Pressure During Simulated Walking, Lawrence Dean Noble Jan 2011

Development Of A Muscle Force Optimization Algorithm To Improve Center Of Pressure During Simulated Walking, Lawrence Dean Noble

ETD Archive

The Universal Musculoskeletal Simulator (UMS) was developed at the Cleveland Clinic to facilitate general purpose orthopaedic research that allows investigators to study the in vitro forces applied to bones, tendons and ligaments during simulated exercise of cadaver joint systems. In its original state, the UMS hardware consisted of a rotopod (a specialized hexapod robot), a single rotary tendon actuator and custom LabVIEW software for coordinated control and operation of the system. The focus of this work was to 1) enhance the UMS with a multi-tendon actuator system, 2) develop a muscle force optimization algorithm and evaluate it with a static …

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Quantification Of Scenedesmus Dimorphus Growth And Substrate Kinetics For Continuous Photobioreactor Design, Daniela Ribita Jan 2011

Quantification Of Scenedesmus Dimorphus Growth And Substrate Kinetics For Continuous Photobioreactor Design, Daniela Ribita

ETD Archive

Increasing gas prices, limited fossil fuel resources and U.S. dependence on foreign oil make research in alternative fuels a priority. The feasibility of producing fuels from microalgae is economically dependent on improvements in lipid productivity by the algae. The research presented here focuses on the development of a mathematical model to describe the biomass and lipid productivity in a continuously-operated photobioreactor (PBR) system. Five different cell lysing methods were evaluated for the purpose of improving the methods of analysis of lipid synthesis. The two most promising methods were found to be mortar and pestle and organic solvent cell fractionation methods. …

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Dietary Supplement Wastewater Treatment By Biological Methods, Xiangting Hou Jan 2011

Dietary Supplement Wastewater Treatment By Biological Methods, Xiangting Hou

ETD Archive

Dietary supplements, pre-mixed meal like Slim Fast, are part of most people's lives. Since dietary supplements have a high order of complex sugars, low-fat milk, and all kinds of nutrients, they bring hazards to the environment if discharged to water bodies without any proper treatment. Therefore, wastewater from dietary supplement gains much more attention at the present time. Dietary supplement wastewater contains amounts of organic compounds which may be bio- friendly and non-toxic. Biological treatment shows its strong advantages in dealing with this kind of wastewater.In this research, four kinds of Live Liquid Micro-organisms (LLMO) were used as the sources …

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Electrocoagulation/Flotation Treatment Of Synthetic Surface Water, Sampath Gunukula Jan 2011

Electrocoagulation/Flotation Treatment Of Synthetic Surface Water, Sampath Gunukula

ETD Archive

Rainfall generated surface runoff water could contaminate groundwater through transportation of suspended solids and organic matter in to the aquifer. Surface runoff water composition mainly depends on soil amendment. Surface runoff mainly contains clay, minerals, organic and inorganic matter, total dissolved lead, zinc. ECF technology presents an alternative for the removal of total suspended solids, turbidity, and organic matter from generated surface runoff water. This research presents development of bench scale ECF unit for the treatment of synthetic surface water. Experiments were conducted in a 10 liter Plexiglas unit provided with two aluminum electrodes, one serving as cathode, and other …

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A Cfd Model Of Mixing In A Microfludic Device For Space Medicine Technology, Terri Lynn Mckay Jan 2011

A Cfd Model Of Mixing In A Microfludic Device For Space Medicine Technology, Terri Lynn Mckay

ETD Archive

The DNA Medicine Institute (DMI) is currently developing a device to be used for blood analysis to satisfy the unique requirements of space medicine applications. A key component of that device is the micromixer, which will ensure mixing and dilution of reagents utilized for detection assays. As part of the device design process, the micromixer was modeled, and the mixing characteristics were analyzed and compared to experimental data. The experimental data was based on a top-view of the system and, lacking data throughout the fluid domain, could not provide the insight into the mixing process that modeling could readily provide. …

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Investigations Of Anatomical Connectivity In The Internal Capsule Of Macaques With Diffusion Magnetic Resonance Imaging, Kyle Andrew Ignatius Taljan Jan 2011

Investigations Of Anatomical Connectivity In The Internal Capsule Of Macaques With Diffusion Magnetic Resonance Imaging, Kyle Andrew Ignatius Taljan

ETD Archive

Understanding anatomical connectivity is crucial for improving outcomes of deep brain stimulation surgery. Tractography is a promising method for noninvasively investigating anatomical connectivity, but connections between subcortical regions have not been closely examined by this method. As many connections to subcortical regions converge at the internal capsule (IC), we investigate the connectivity through the IC to three subcortical nuclei (caudate, lentiform nucleus, and thalamus) in 6 macaques. We show that a statistical correction for a known distance-related artifact in tractography results in large changes in connectivity patterns. Our results suggest that care should be taken in using tractography to assess …

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Intelligent Controls For A Semi-Active Hydraulic Prosthetic Knee, Timothy Allen Wilmot Jan 2011

Intelligent Controls For A Semi-Active Hydraulic Prosthetic Knee, Timothy Allen Wilmot

ETD Archive

We discuss open loop control development and simulation results for a semi-active above-knee prosthesis. The control signal consists of two hydraulic valve settings. These valves control a rotary actuator that provides torque to the prosthetic knee. We develop open loop control using biogeography-based optimization (BBO), which is a recently developed evolutionary algorithm, and gradient descent. We use gradient descent to show that the control generated by BBO is locally optimal. This research contributes to the field of evolutionary algorithms by demonstrating that BBO is successful at finding optimal solutions to complex, real-world, nonlinear, time varying control problems. The research contributes …

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Measuring The Environmental Impact Of Embedded/Bankfull Culverts, Joseph A. Pavlick Jan 2011

Measuring The Environmental Impact Of Embedded/Bankfull Culverts, Joseph A. Pavlick

ETD Archive

Streams are dynamic systems constantly changing over time. The health of a stream system is tied to the amount of sedimentation occurring in a stream. The addition of roadway culverts into a stream has been shown to cause erosion and sedimentation problems if the culvert does not meet stream characteristics of slope, bankfull/width, and channel orientation. This has led to the design of embedded/bankfull culverts. In the State of Ohio, the Ohio Environmental Protection Agency and the United States Army Corps of Engineers now require the Ohio Transportation to install embedded/bankfull culverts at all stream locations during new roadway construction. …

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Measurement Of White Matter Structure Changes In Amyotrophic Lateral Sclerosis Using Fractal Analysis, Zao Liu Jan 2011

Measurement Of White Matter Structure Changes In Amyotrophic Lateral Sclerosis Using Fractal Analysis, Zao Liu

ETD Archive

Amyotrophic lateral sclerosis (ALS) is recognized as a motor neuron disorder affecting the structure and function of the brain and neuromuscular system. Very little is known, however, that the nervous system degeneration is dependent on disease phenotypes of ALS. The purpose of this study was to determine the degree of brain white matter (WM) structure degeneration in four ALS patient groups characterized by their clinical signs and neuroimaging measurements. Fractal dimension (FD) of three-dimensional (3D) brain WM images was quantitatively analyzed to evaluate the WM structural complexity, including complexity levels of the WM skeleton, surface and general structures in ALS …

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Restoration Of Emergent Sandbar Habitat Complexes In The Missouri River, North Dakota Jan 2011

Restoration Of Emergent Sandbar Habitat Complexes In The Missouri River, North Dakota

United States Army Corps of Engineers, Omaha District

In 2003, the United States Fish and Wildlife Service (USFWS) issued an Amendment to the 2000 Biological Opinion (BiOp) with recommendations for the US Army Corps of Engineers’ (Corps) operations on the Missouri River Mainstem System (MRMS). The BiOp Amendment was the result of continuing consultation between the Corps and the USFWS under the Endangered Species Act (ESA) and supplemented the recommendations given in the previous BiOp (USFWS, 2000). The 2000 BiOp and amendments made in 2003 will be collectively referred to as “BiOp” hereafter. The document found that Corps operations on the Missouri River were not likely to jeopardize …

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Protective Immunity To Pre-Erythrocytic Stage Malaria, Robert J. Schwenk, Thomas L. Richie Jan 2011

Protective Immunity To Pre-Erythrocytic Stage Malaria, Robert J. Schwenk, Thomas L. Richie

United States Army: Publications

The development of a vaccine against malaria is a major research priority given the burden of disease, death and economic loss inflicted upon the tropical world by this parasite. Despite decades of effort, however, a vaccine remains elusive. The best candidate is a subunit vaccine termed RTS,S but this provides only partial protection against clinical disease. This review examines what is known about protective immunity against pre-erythrocytic stage malaria by considering the humoral and T cell-mediated immune responses that are induced by attenuated sporozoites and by the RTS,S vaccine. On the basis of these observations a set of research priorities …

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Determination Of Threshold Adverse Effect Doses Of Percutaneous Vx Exposure In African Green Monkeys, Raymond F. Genovese, Bernard J. Benton, John L. Oubre, Christopher E. Byers, E. Michael Jakubowski, Robert J. Mioduszewski, Timothy J. Settle, Thomas J. Steinbach Jan 2011

Determination Of Threshold Adverse Effect Doses Of Percutaneous Vx Exposure In African Green Monkeys, Raymond F. Genovese, Bernard J. Benton, John L. Oubre, Christopher E. Byers, E. Michael Jakubowski, Robert J. Mioduszewski, Timothy J. Settle, Thomas J. Steinbach

United States Army: Publications

Percutaneous exposure to the chemical warfare nerve agent VX was evaluated in African green monkeys (n = 9). Doses of VX (7.5–100 μg/kg) were applied to the skin for 60 min and residual agent was quantified (before decontamination) to estimate the absorbed dose. Monkeys were evaluated for the presence or absence of clinical signs of toxicity and blood was sampled periodically (30 min–12 weeks) following exposure to measure the degree of circulating acetylcholinesterase (AChE) inhibition. Monkeys were also evaluated for behavioral changes fromVXexposure using a serial probe recognition (SPR) task. The lowest observable adverse effect level (LOAEL) for the production …

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Mechanical Response Of Pig Skin Under Dynamic Tensile Loading, Jaeyoung Lim, Jihye Hong, Weinong W. Chen, Tusit Weerasooriya Jan 2011

Mechanical Response Of Pig Skin Under Dynamic Tensile Loading, Jaeyoung Lim, Jihye Hong, Weinong W. Chen, Tusit Weerasooriya

United States Army: Publications

Uniaxial tensile experiments were performed on pig skin to investigate the tensile stressestrain response at both quasi-static and dynamic rates of deformation. A Kolsky tension bar, also called a split Hopkinson tension bar (SHTB), was modified to conduct the dynamic experiments. Semiconductor strain gages were used to measure the low levels of the transmitted signal from pig skin. A pulse shaper technique was used for generating a suitable incident pulse to ensure stress equilibrium and approximate constant strain rate in the specimen of a thin skin sheet wrapped around the ends of the bars for minimizing radial inertia. In order …

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Detection Of Six Serotypes Of Botulinum Neurotoxin Using Fluorogenic Reporters, Daniel R. Ruge, F. Mark Dunning, Timothy M. Piazza, Brian E. Molles, Michael Adler, Füsûn N. Zeytin, Ward C. Tucker Jan 2011

Detection Of Six Serotypes Of Botulinum Neurotoxin Using Fluorogenic Reporters, Daniel R. Ruge, F. Mark Dunning, Timothy M. Piazza, Brian E. Molles, Michael Adler, Füsûn N. Zeytin, Ward C. Tucker

United States Army: Publications

Methods that do not require animal sacrifice to detect botulinum neurotoxins (BoNTs) are critical for BoNT antagonist discovery and the advancement of quantitative assays for biodefense and pharmaceutical applications. Here we describe the development and optimization of fluorogenic reporters that detect the proteolytic activity of BoNT/A, B, D, E, F, and G serotypes in real time with femtomolar to picomolar sensitivity. Notably, the reporters can detect femtomolar concentrations of BoNT/A in 4 h and BoNT/E in 20 h, sensitivity that equals that of animal-based methods. The reporters can be used to determine the specific activity of BoNT preparations with intra- …

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Prophylaxis With Human Serum Butyrylcholinesterase Protects Guinea Pigs Exposed To Multiple Lethal Doses Of Soman Or Vx, Ashima Saxena, Wei Sun, James M. Fedorko, Irwin Koplovitz, Bhupendra P. Doctor Jan 2011

Prophylaxis With Human Serum Butyrylcholinesterase Protects Guinea Pigs Exposed To Multiple Lethal Doses Of Soman Or Vx, Ashima Saxena, Wei Sun, James M. Fedorko, Irwin Koplovitz, Bhupendra P. Doctor

United States Army: Publications

Human serum butyrylcholinesterase (Hu BChE) is currently under advanced development as a bioscavenger for the prophylaxis of organophosphorus (OP) nerve agent toxicity in humans. It is estimated that a dose of 200 mg will be required to protect a human against 2 × LD50 of soman. To provide data for initiating an investigational new drug application for the use of this enzyme as a bioscavenger in humans, we purified enzyme from Cohn fraction IV-4 paste and initiated safety and efficacy evaluations in mice, guinea pigs, and non-human primates. In mice, we demonstrated that a single dose of enzyme that …

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Reinforced Chitosan-Based Heart Valve Scaffold And Utility Of Bone Marrow-Derived Mesenchymal Stem Cells For Cardiovascular Tissue Engineering, Mohammad Z. Albanna Jan 2011

Reinforced Chitosan-Based Heart Valve Scaffold And Utility Of Bone Marrow-Derived Mesenchymal Stem Cells For Cardiovascular Tissue Engineering, Mohammad Z. Albanna

Wayne State University Dissertations

Recent research has demonstrated a strong correlation between the differentiation profile of mesenchymal stem cells (MSCs) and scaffold stiffness. Chitosan is being widely studied for tissue engineering applications due to its biocompatibility and biodegradability. However, its use in load-bearing applications is limited due to moderate to low mechanical properties. In this study, we investigated the effectiveness of a fiber reinforcement method for enhancing the mechanical properties of chitosan scaffolds. Chitosan fibers were fabricated using a solution extrusion and neutralization method and incorporated into porous chitosan scaffolds. The effects of different fiber/scaffold mass ratios, fiber mechanical properties and fiber lengths on …

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Artificial And Natural Nucleic Acid Self Assembling Systems, Marcus Wood Jan 2011

Artificial And Natural Nucleic Acid Self Assembling Systems, Marcus Wood

Wayne State University Dissertations

Nucleic acids are good candidates for nanomachine construction. They participate in all the processes of life, and so can function as structural building blocks and dynamic catalysts. However, to use nucleic acids as nanomachines, a better understanding of their material properties, how to design structures using them, and their dynamics is needed. We have tried to address these issues, in a small way, with nucleic acid force field development, an attempt at nanostructural design and synthesis using DNA, and a study of the RNA/protein regulatory dynamics of the tryptophan regulatory attenuation protein.

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An Investigation Of The Biomechanical Response From Shock Wave Loading To The Head, Alessandra Dal Cengio Leonardi Jan 2011

An Investigation Of The Biomechanical Response From Shock Wave Loading To The Head, Alessandra Dal Cengio Leonardi

Wayne State University Dissertations

There is a pressing need for a comprehensive explanation of the mechanism of brain injury after exposure to blast and several hypotheses have been suggested. The focus of this research was to investigate one of the hypotheses for primary brain injury due to blast: multimodal skull flexure. The significance of this research is twofold. First, resolution of the mode of energy transfer and of the induced stresses within the skull-brain system will allow for creations of mitigation/protective techniques/equipment, as well as design of experiments investigating live-cell response using more reliable physical models. Second, the data obtained experimentally will be available …

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Pamam Dendrimer-Based Therapeutic And Diagnostic Nanodevices, Admira Bosnjakovic Jan 2011

Pamam Dendrimer-Based Therapeutic And Diagnostic Nanodevices, Admira Bosnjakovic

Wayne State University Dissertations

Dendrimers are ideal materials to be used in the emerging field of nanomedicine. Their nanoscale size and high density of functional groups on their peripheries allow them to be used for various biomedical applications. This work exploits dendrimers as drug delivery vehicles and a versatile platform for capturing biomarkers with improved sensitivity and specificity. Hydroxyl terminated poly(amidoamine) dendrimer (PAMAM-OH) was modified with a linker having amine group at the end and conjugated to two drugs, erythromycin (EM) and allopregnanonolne, respectively and evaluated in vitro. Both drugs were provided with a linker having carboxylic group required for conjugation reaction with dendrimer. …

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The Rock 2011, School Of Engineering And Computer Science Jan 2011

The Rock 2011, School Of Engineering And Computer Science

The Rock

No abstract provided.

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Automated Analysis Of Mouse Serum Peptidome Using Restricted Access Media And Nanoliquid Chromatography–Tandem Mass Spectrometry, Geun-Cheol Gil, Jim Brennan, Dan Throckmorton, Steven Branda, Gabriela Chirica Jan 2011

Automated Analysis Of Mouse Serum Peptidome Using Restricted Access Media And Nanoliquid Chromatography–Tandem Mass Spectrometry, Geun-Cheol Gil, Jim Brennan, Dan Throckmorton, Steven Branda, Gabriela Chirica

United States Department of Energy: Publications

We demonstrate use of restricted access media with reversed phase functionality (RAM-RP) for analysis of low molecular weight proteins and peptides in mouse serum (75ml) using a custom designed modular automated processing system (MAPS). RAM-RP fractionation with simultaneous removal of high molecular weight and high abundance proteins is integrated with a follow-on buffer exchange module (BE) to ensure compatibility with subsequent processing steps (trypsin digestion and intact peptide separation prior to mass spectrometric analysis). The high sample capacity afforded by chromatographic methods generates enough sample to achieve comprehensive serum peptidome identification (357 proteins) through tandem mass spectrometric analysis of both …

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Reducing Error And Measurement Time In Impedance Spectroscopy Using Model Based Optimal Experimental Design, Francesco Ciucci, Thomas Carraro, William Chueh, Wei Lai Jan 2011

Reducing Error And Measurement Time In Impedance Spectroscopy Using Model Based Optimal Experimental Design, Francesco Ciucci, Thomas Carraro, William Chueh, Wei Lai

United States Department of Energy: Publications

In this work we introduce several novel tools for the reduction of errors in parameters estimated with electrochemical impedance spectroscopy experiments. An optimization strategy is developed that minimizes an estimate of the errors on the parameters while bounding the experimental time. The approach is also used to reduce experimental time while keeping a bound on the parameter errors. This feature is particularly critical in systems changing significantly within the experimental time. The paper uses a fuel cell electrode model to test this methodology and presents a real time algorithm for coupling experiment with the parameter estimation and experimental optimization.

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Solution And Microbial Controls On The Formation Of Reduced U(Iv) Species, Maxim I. Boyanov, Kelly E. Fletcher, Man Jae Kwon, Xue Rui, Edward J. O’Loughlin, Frank E. Löffler, Kenneth M. Kemner Jan 2011

Solution And Microbial Controls On The Formation Of Reduced U(Iv) Species, Maxim I. Boyanov, Kelly E. Fletcher, Man Jae Kwon, Xue Rui, Edward J. O’Loughlin, Frank E. Löffler, Kenneth M. Kemner

United States Department of Energy: Publications

Reduction of UVI to UIV as the result of direct or indirect microbial activity is currently being explored for in situ remediation of subsurface U plumes, under the assumption that UIV solubility is controlled by the low solubility mineral uraninite (UIV-dioxide). However, recent characterizations of U in sediments from biostimulated field sites, as well as laboratory UVI bioreduction studies, report on the formation of UIV species that lack the U=O2=U coordination of uraninite, suggesting that phases other than uraninite may be controlling UIV solubility in environments with complexing surfaces and ligands. …

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Identification And Characterization Of Undahrcr-6, An Outer Membrane Endecaheme C-Type Cytochrome Of Shewanella Sp. Strain Hrcr-6, Liang Shi, Sara M. Belchik, Zheming Wang, David W. Kennedy, Alice C. Dohnalkova, Matthew J. Marshall, John M. Zachara, James K. Fredrickson Jan 2011

Identification And Characterization Of Undahrcr-6, An Outer Membrane Endecaheme C-Type Cytochrome Of Shewanella Sp. Strain Hrcr-6, Liang Shi, Sara M. Belchik, Zheming Wang, David W. Kennedy, Alice C. Dohnalkova, Matthew J. Marshall, John M. Zachara, James K. Fredrickson

United States Department of Energy: Publications

UndAHRCR-6 was identified from the metal-reducing bacterium Shewanella sp. strain HRCR-6. Both in vivo and in vitro characterization results indicate that UndAHRCR-6 is an outer membrane endecaheme c-type cytochrome and probably has a key functional role in the extracellular reduction of iron [Fe(III)] oxides and uranium [U(VI)] by Shewanella sp. HRCR-6.

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Purification And Characterization Of The [Nife]-Hydrogenase Of Shewanella Oneidensis Mr-1, Liang Shi, Sara M. Belchik, Andrew E. Plymale, Steve Heald, Alice C. Dohnalkova, Kateryna Sybirna, Herve Bottin, Thomas C. Squier, John M. Zachara, James K. Fredrickson Jan 2011

Purification And Characterization Of The [Nife]-Hydrogenase Of Shewanella Oneidensis Mr-1, Liang Shi, Sara M. Belchik, Andrew E. Plymale, Steve Heald, Alice C. Dohnalkova, Kateryna Sybirna, Herve Bottin, Thomas C. Squier, John M. Zachara, James K. Fredrickson

United States Department of Energy: Publications

Shewanella oneidensis MR-1 possesses a periplasmic [NiFe]-hydrogenase (MR-1 [NiFe]-H2ase) that has been implicated in H2 production and oxidation as well as technetium [Tc(VII)] reduction. To characterize the roles of MR-1 [NiFe]-H2ase in these proposed reactions, the genes encoding both subunits of MR-1 [NiFe]-H2ase were cloned and then expressed in an MR-1 mutant without hyaB and hydA genes. Expression of recombinant MR-1 [NiFe]-H2ase in trans restored the mutant’s ability to produce H2 at 37% of that for the wild type. Following purification, MR-1 [NiFe]-H2ase coupled H2 oxidation to …

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Microbial Reduction Of Chlorite And Uranium Followed By Air Oxidation, Gengxin Zhang, William D. Burgos, John M. Senko, Michael E. Bishop, Hailiang Dong, Maxim Boyanov, Kenneth M. Kemner Jan 2011

Microbial Reduction Of Chlorite And Uranium Followed By Air Oxidation, Gengxin Zhang, William D. Burgos, John M. Senko, Michael E. Bishop, Hailiang Dong, Maxim Boyanov, Kenneth M. Kemner

United States Department of Energy: Publications

To evaluate the stability of biogenic nanoparticulate U(IV) in the presence of an Fe(II)-rich iron-bearing phyllosilicate, we examined the reduction of structural Fe(III) in chlorite CCa-2 and uranium(VI) by Shewanella oneidensis MR-1, and the reoxidation of these minerals (after pasteurization) via the introduction of oxygen. Bioreduction experiments were conducted with combinations of chlorite, U(VI), and anthraquinone-2,6-disulfonate (AQDS). Abiotic experiments were conducted to quantify the reduction of U(VI) by chemically-reduced chlorite-associated Fe(II), the oxidation of nanoparticulate U(IV) by unaltered structural Fe(III) in chlorite, and the sorption of U(VI) to chlorite, to elucidate interactions between U(VI)/ U(IV) and Fe(II)/Fe(III)-chlorite. Solids were characterized …

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Competitive Reduction Of Pertechnetate (99tco4-) By Dissimilatory Metal Reducing Bacteria And Biogenic Fe(Ii), Andrew Plymale, James K. Fredrickson, John M. Zachara, Alice Dohnalkova, Steve Heald, Dean Moore, David Kennedy, Matthew Marshall, Chongmin Wang, Charles Resch, Ponnusamy Nachimuthu Jan 2011

Competitive Reduction Of Pertechnetate (99tco4-) By Dissimilatory Metal Reducing Bacteria And Biogenic Fe(Ii), Andrew Plymale, James K. Fredrickson, John M. Zachara, Alice Dohnalkova, Steve Heald, Dean Moore, David Kennedy, Matthew Marshall, Chongmin Wang, Charles Resch, Ponnusamy Nachimuthu

United States Department of Energy: Publications

The fate of pertechnetate (99Tc(VII)O4 -) during bioreduction was investigated in the presence of 2-line ferrihydrite (Fh) and various dissimilatory metal reducing bacteria (DMRB) (Geobacter, Anaeromyxobacter, Shewanella) in comparison with TcO4 - bioreduction in the absence of Fh. In the presence of Fh, Tc was present primarily as a fine-grained Tc(IV)/Fe precipitate that was distinct from the Tc(IV)O2 ·nH2O solids produced by direct biological Tc(VII) reduction. Aqueous Tc concentrations (<0.2 μm) in the bioreduced Fh suspensions (1.7 to 3.2 × 10-9 mol L-1) were over 1 order of magnitude lower than when TcO4 - …

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Effect Of Grain Size On Uranium(Vi) Surface Complexation Kinetics And Adsorption Additivity, Jianying Shang, Chongxuan Liu, Zheming Wang, John M. Zachara Jan 2011

Effect Of Grain Size On Uranium(Vi) Surface Complexation Kinetics And Adsorption Additivity, Jianying Shang, Chongxuan Liu, Zheming Wang, John M. Zachara

United States Department of Energy: Publications

The contribution of variable grain sizes to uranium adsorption/ desorption was studied using a sediment from the US DOE Hanford site. The sediment was wet sieved into four size fractions: coarse sand (1−2 mm), medium sand (0.2−1 mm), fine sand (0.053−0.2 mm), and clay/silt fraction (<0.053 mm). For each size fraction and their composite (sediment), batch and flow-cell experiments were performed to determine uranium adsorption isotherms and kinetic uranium adsorption and subsequent desorption. The results showed that uranium adsorption isotherms and adsorption/desorption kinetics were size specific, reflecting the effects of size-specific adsorption site concentration and kinetic rate constants. The larger-size fraction had a larger mass percentage in the sediment but with a smaller adsorption site concentration and generally a slower uranium adsorption/desorption rate. The same equilibrium surface complexation reaction and reaction constant could describe uranium adsorption isotherms for all size fractions and the composite after accounting for the effect of adsorption site concentration. Mass-weighted, linear additivity was observed for both uranium adsorption isotherms and adsorption/desorption kinetics in the composite. One important implication of this study is that grain-size distribution may be used to estimate uranium adsorption site and adsorption/desorption kinetic rates in heterogeneous sediments from a common location.

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Determining Individual Mineral Contributions To U(Vi) Adsorption In A Contaminated Aquifer Sediment: A Fluorescence Spectroscopy Study, Zheming Wang, John M. Zachara, Jean-Francois Boily, Yuanxian Xia, Tom C. Resch, Dean A. Moore, Chongxuan Liu Jan 2011

Determining Individual Mineral Contributions To U(Vi) Adsorption In A Contaminated Aquifer Sediment: A Fluorescence Spectroscopy Study, Zheming Wang, John M. Zachara, Jean-Francois Boily, Yuanxian Xia, Tom C. Resch, Dean A. Moore, Chongxuan Liu

United States Department of Energy: Publications

The adsorption and speciation of U(VI) was investigated on contaminated, fine grained sediment materials from the Hanford 300 area (SPP1 GWF) in simulated groundwater using cryogenic laser-induced U(VI) fluorescence spectroscopy combined with chemometric analysis. A series of reference minerals (montmorillonite, illite, Michigan chlorite, North Carolina chlorite, California clinochlore, quartz and synthetic 6-line ferrihydrite) was used for comparison that represents the mineralogical constituents of SPP1 GWF. Surface area-normalized Kd values were measured at U(VI) concentrations of 5 X 10−7 and 5 X 10−6 mol L−1 that displayed the following affinity series: 6-line-ferrihydrite > North Carolina chlorite ≈ California clinochlore …

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