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Masters Theses

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Articles 481 - 510 of 2077

Full-Text Articles in Physical Sciences and Mathematics

Role Of Feedstock And Process Conditions On Biomass Gasification For Synthesis Gas Production, Mayoorey Murugathasan Jan 2014

Role Of Feedstock And Process Conditions On Biomass Gasification For Synthesis Gas Production, Mayoorey Murugathasan

Masters Theses

In this study gasification of three different biomasses were performed to study the impact of process conditions and different feed stocks on final syngas composition. Final composition of the syngas determines the energy value of the resulting syngas and the suitability of syngas in chemical synthesis applications. Three kinds of feedstocks studied include switch grass pellets:wood chips 50:50 mixture, wood pellets:wood chips 50:50 mixture and wood pellets.

The effect of process conditions including temperature and feed stock composition on syngas composition were studied. Gas chromatography was used to analyze the final gas composition of syngas samples collected at five different …


Low Resolution Examination Of Cool-Water Carbonate Foraminifera Around Tasmania During The Pleistocene, Sara Jane Hughes Jan 2014

Low Resolution Examination Of Cool-Water Carbonate Foraminifera Around Tasmania During The Pleistocene, Sara Jane Hughes

Masters Theses

Benthic foraminifera from nine sediment samples recovered during Ocean Drilling Program (ODP) Leg 189: The Tasman Gateway were examined to determine how changing Southern Ocean conditions affect benthic foraminiferal populations. All samples come from Site 1168 situated 70km from the coast of Tasmania on the western continental slope (2463 m below the surface) and are spaced at roughly 150,000 years apart. Identifications of benthic foraminifera were done with a dissecting microscope and several reference books. Foraminifera were correlated with environmental proxy data obtained from Brughmans (2003) (total organic carbon, carbonate, siliciclastics, coarse fractions, chlorin, barium, aluminum, iron, and titanium) and …


Computational And Experimental Studies Of Non-Covalent Interactions: Characterization Of Ch...Π Interactions And Structure Of 1,1-Difluoroethylene...Carbon Dioxide, Ashley M. Anderton Jan 2014

Computational And Experimental Studies Of Non-Covalent Interactions: Characterization Of Ch...Π Interactions And Structure Of 1,1-Difluoroethylene...Carbon Dioxide, Ashley M. Anderton

Masters Theses

Weakly bound CH/π interactions, due to the abundance of C-H bonds and π systems that exist in larger organic molecules, are an important driving force in the construction of biomacromolecules, supramolecular assemblies and crystal packing of organic compounds. To assist in the characterization of CH/π interactions, a density functional theory (DFT) study has been conducted to determine a quick and cheap method for accurate determination of the binding energy and rotational constants for CH/π interactions. Seven complexes were used in this study: five benzene-HY complexes (where Y= C≡CH, Cl, F, Br and C≡N) and two fluorobenzene-HY complexes (where Y= C≡CH …


Investigations Towards Synthesis Of Cinnamaldehyde Semicarbazone Derivatives And Their Photochromicity By Modifying The Ring, The Linker, And The Semicarbazone, Xiao Xiao Jan 2014

Investigations Towards Synthesis Of Cinnamaldehyde Semicarbazone Derivatives And Their Photochromicity By Modifying The Ring, The Linker, And The Semicarbazone, Xiao Xiao

Masters Theses

Cinnamaldehyde semicarbazone was varied in three ways, by altering the ring, the conjugated linker, and the semicarbazone, to investigate how changing the structure affects the photochomicity. The synthesis of 7 hetero- and 2 polycyclic- aromatic semicarbazone variants involved three steps, (a Wittig reaction, hydrolysis, and condensation to the semicarbazone) with cumulative yields of 15% to 52%. Generally, the pyridine series gave lower yields than other synthesized semicarbazones. The Wittig reaction gave cis/trans mixtures in ratios of 2 : 1 to 1 : 7 for the 6 acetals, except for the 3 that went directly to the aldehyde, due to the …


Synthesis And Characterization Of Molecular Components For The Preparation Of Poly-Rotaxanes, Austin P. Welti Jan 2014

Synthesis And Characterization Of Molecular Components For The Preparation Of Poly-Rotaxanes, Austin P. Welti

Masters Theses

The self-sorting ability of certain crown ethers make them important players in the field of supramolecular chemistry, especially those studying mechanically interlocked molecules (MIMs). Of these MIMs, rotaxanes and catenanes are the most common. Our approach in the synthesis of poly-rotaxane systems involves the preparation of axles containing multiple recognition motifs to determine the self-sorting principles that each motif shows. These principles include narcissistic self-sorting, and also type I and type II social self-sorting principles. Using these techniques, poly-rotaxane formation can be made readily available.

A hetero-poly-rotaxane equipped with a naphthalene diimide (NDI) site and two ammonium salt sites has …


An Investigation Of Contaminant Metal Distribution And Mineral Speciation In The Soil Near The Buick Recycling Division Smelter, Iron County, Missouri, Krista Nicole Rybacki Jan 2014

An Investigation Of Contaminant Metal Distribution And Mineral Speciation In The Soil Near The Buick Recycling Division Smelter, Iron County, Missouri, Krista Nicole Rybacki

Masters Theses

"Trace metal contamination studies were conducted near the Buick Resource Recycling Division. This study used sequential extraction, total digestion, X-Ray Diffraction (XRD), and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) to study trace metals in two soil cores. Sequential extraction analysis of the soil cores revealed that lead was associated with either iron or manganese oxides. Zinc and copper were bound to soil components, extracted mainly from organics, sulfides, and clays. Total digestion results compared favorably to the sum of the sequential extraction results for lead, thus validating the sequential extraction methodology. The highest concentration observed for lead was 4,743 parts …


Characterization Of A Plant Gene Family Expanded In Glycine Max, Lisa Snoderly-Foster Jan 2014

Characterization Of A Plant Gene Family Expanded In Glycine Max, Lisa Snoderly-Foster

Masters Theses

"Glycine max, commonly named the cultivated soybean, is one of the oldest and most important food crops in the world. The study of the G. max genome provides valuable insight into the molecular mechanisms that govern its reproduction and environmental responsiveness, key factors in maximizing crop yield. Since the complete sequencing of the genome in 2010, the analysis has become faster and easier, especially with the development of numerous web-based, publically accessible bioinformatics tools.

This research effort utilizes these tools to characterize a small, unannotated G. max gene family. Although no definitive evidence was uncovered for the production of a …


A Receiver Function Study Of Crust Thickness And Composition Beneath The Southwestern United States, Si Wu Jan 2014

A Receiver Function Study Of Crust Thickness And Composition Beneath The Southwestern United States, Si Wu

Masters Theses

"Over the past decades, the seismic structure of the crust and upper mantle of the southwestern United States was examined using an array of different methods. The structure and composition of crust received special attentions, most due to the hydrocarbon reserves in this area. Here new constraints on crustal evolution and structure models are provide by systematically analyzing 37,402 receiver functions recorded at 234 seismic stations on the southwestern United States. The results reveal that the Transitional Crust is characterized by a thin (29.0±1.0 km) crust, a low Vp/Vs ratio of 1.76±0.016 and a high amplitude (R) of P-to-S converted …


Adaptive Wavelet Discretization Of Tensor Products In H-Tucker Format, Mazen Ali Jan 2014

Adaptive Wavelet Discretization Of Tensor Products In H-Tucker Format, Mazen Ali

Masters Theses

"In previous work, the solution to a system of coupled parabolic PDEs, modeling the price of a CDO, was approximated numerically. Due to the nature of the problem, the system involved a large number of equations such that the parameters cannot be stored explicitly. The authors combined the data sparse H-Tucker storage format with the Galerkin method to approximate the solution, using wavelets for the space discretization together with time stepping (Method of Lines). The aforementioned approximation is of the linear kind, i.e., using a nonadaptive method. In this work, three methods for solving such systems adaptively are presented, together …


An Empirical Study On Symptoms Of Heavier Internet Usage Among Young Adults, Saipreethi Vishwanathan Jan 2014

An Empirical Study On Symptoms Of Heavier Internet Usage Among Young Adults, Saipreethi Vishwanathan

Masters Theses

"Understanding negative consequences of heavy Internet use on mental health is a topic that is gaining significant traction recently. A number of studies have investigated heavy Internet usage, especially among young adults in relation to online games, social media and email. While such studies do provide valuable insights, Internet usage so far has been characterized by means of self-reported surveys only that may suffer from errors and biases. In this paper, we report the findings of a two month empirical study on heavy Internet usage among students conducted at a college campus. The novelty of the study is that it …


Cervical Cancer Histology Image Feature Extraction And Classification, Peng Guo Jan 2014

Cervical Cancer Histology Image Feature Extraction And Classification, Peng Guo

Masters Theses

"Cervical cancer, the second most common cancer affecting women worldwide and the most common in developing countries can be cured if detected early and treated. Expert pathologists routinely visually examine histology slides for cervix tissue abnormality assessment. In previous research, an automated, localized, fusion-based approach was investigated for classifying squamous epithelium into Normal, CIN1, CIN2, and CIN3 grades of cervical intraepithelial neoplasia (CIN) based on image analysis of 62 digitized histology images obtained through the National Library of Medicine. In this research, CIN grade assessments from two pathologists are analyzed and are used to facilitate atypical cell concentration feature development …


Dephosphorylation Of Iqg1 By Cdc14 Temporally Regulates Actin Ring Formation, Daniel Patrick Miller Jan 2014

Dephosphorylation Of Iqg1 By Cdc14 Temporally Regulates Actin Ring Formation, Daniel Patrick Miller

Masters Theses

"Cytokinesis is the final step in cell division when the cell separates the cytoplasm by contracting a ring composed of filamentous actin (F-actin) and type II myosin. Iqg1, an IQGAP family member, is an essential scaffolding protein in budding yeast (S. cerevisiae) required for actin recruitment to, and contraction of, the actomyosin ring. Actin is recruited by the calponin homology domain (CHD) in anaphase after Iqg1 is localized to the bud neck. Consensus sites for the cyclin-dependent kinase (CDK) Cdc28 were identified flanking the CHD. This led us to the hypothesis that phosphorylation of Iqg1 by Cdc28 negatively regulates actin …


Evolving Decision Trees For The Categorization Of Software, Jasenko Hosic Jan 2014

Evolving Decision Trees For The Categorization Of Software, Jasenko Hosic

Masters Theses

"Current manual techniques of static reverse engineering are inefficient at providing semantic program understanding. An automated method to categorize applications was developed in order to quickly determine pertinent characteristics. Prior work in this area has had some success, but a major strength of the approach detailed in this thesis is that it produces heuristics that can be reused for quick analysis of new data. The method relies on a genetic programming algorithm to evolve decision trees which can be used to categorize software. The terminals, or leaf nodes, within the trees each contain values based on selected features from one …


M-Grid : A Distributed Framework For Multidimensional Indexing And Querying Of Location Based Big Data, Shashank Kumar Jan 2014

M-Grid : A Distributed Framework For Multidimensional Indexing And Querying Of Location Based Big Data, Shashank Kumar

Masters Theses

"The widespread use of mobile devices and the real time availability of user-location information is facilitating the development of new personalized, location-based applications and services (LBSs). Such applications require multi-attribute query processing, handling of high access scalability, support for millions of users, real time querying capability and analysis of large volumes of data. Cloud computing aided a new generation of distributed databases commonly known as key-value stores. Key-value stores were designed to extract value from very large volumes of data while being highly available, fault-tolerant and scalable, hence providing much needed features to support LBSs. However complex queries on multidimensional …


Assessment Of Contributing Factors To The Reduction Of Diarrhea In Rural Communities Of Para, Brazil, Lee Voth-Gaeddert Jan 2014

Assessment Of Contributing Factors To The Reduction Of Diarrhea In Rural Communities Of Para, Brazil, Lee Voth-Gaeddert

Masters Theses

"In developing communities the occurrence of diarrhea has been reported at elevated levels as compared to those communities in more developed regions. Diarrheal diseases were linked to over one million deaths in 2012 throughout the world. While multiple pathways are present for the transmission of diarrheal diseases, water has been the focus for many aid organizations. Point-of-use (POU) water treatment methods are a common tool used by aid organizations in efforts to provide potable water. The CAWST biosand filter is a POU tool that has shown removal effectiveness of pathogenic microorganisms ranging from 90-99%. However, minimal literature was found that …


Gold-Magnetite Nanoparticle-Biomolecule Conjugates: Synthesis, Properties And Toxicity Studies, Akshay Pariti Jan 2014

Gold-Magnetite Nanoparticle-Biomolecule Conjugates: Synthesis, Properties And Toxicity Studies, Akshay Pariti

Masters Theses

"This thesis study focuses on synthesizing and characterizing gold-magnetite optically active magnetic nanoparticle and its conjugation with biomolecules for biomedical applications, especially magnetic fluid hyperthermia treatment for cancerous tissue. Gold nanoparticles have already displayed their potential in the biomedical field. They exhibit excellent optical properties and possess strong surface chemistry which renders them suitable for various biomolecule attachments. Studies have showed gold nanoparticles to be a perfect biocompatible vector. However, clinical trials for gold mediated drug delivery and treatment studied in rat models identified some problems. Of these problems, the low retention time in bloodstream and inability to maneuver externally …


Origin Of High Levels Of Ammonium In Groundwater, Ottawa County, Michigan, Derrick Lingle Dec 2013

Origin Of High Levels Of Ammonium In Groundwater, Ottawa County, Michigan, Derrick Lingle

Masters Theses

Groundwater from wells located in and around Hemlock Crossing Park in Ottawa County, Michigan has elevated levels of ammonium. High ammonium concentrations in potable water wells are a common indicator of anthropogenic impact, such as landfill leachate or agricultural activity. Ammonium can also occur in groundwater through the decay of natural organic material. Along with the retrieval of a complete glacial sediment core via rotasonic drilling, numerous chemical and isotopic parameters were used to determine the source of ammonium in the impacted aquifer.

Buried organic material, deposited during the Athens subepisode interglacial period, is in contact with groundwater containing elevated …


Utilizing Persistent Scatterer Interferometry To Investigate The Nature And Factors Controlling Nile Delta Subsidence, El Hachemi Yousef Bouali Dec 2013

Utilizing Persistent Scatterer Interferometry To Investigate The Nature And Factors Controlling Nile Delta Subsidence, El Hachemi Yousef Bouali

Masters Theses

The Nile Delta in Egypt is being threatened by two continuous and relatively slow hazards: encroachment from the Mediterranean Sea as sea levels rise and land subsidence of the delta itself. The magnitude of sea level rise has been actively monitored, while the subsidence of the Nile Delta has not been adequately quantified spatially and temporally. Instead, all previous studies have either focused on measuring average Holocene subsidence rates or modern subsidence rates on local scales (point- or city-scale).

The overall study objective is three-fold: (1) to measure and map the spatial variations in subsidence rates across the entire Nile …


Stratigraphic Controls On Diagenetic Pathways In The St. Peter Sandstone, Michigan Basin, Stephen A. Zdan Dec 2013

Stratigraphic Controls On Diagenetic Pathways In The St. Peter Sandstone, Michigan Basin, Stephen A. Zdan

Masters Theses

The Middle Ordovician St. Peter Sandstone in the Michigan Basin is a target for hydrocarbon exploration/production, and carbon sequestration and geologic storage. The St. Peter is predominantly a marine sandstone with four dominant lithofacies. The uppermost facies contains zones of porosity and good reservoir quality. Because of the mostly uniform detrital composition, diagenesis must play a leading role in reservoir quality development. This study tests stratigraphic controls on diagenesis and reservoir quality development. The distribution of diagenetic regimes is believed to result from depositional setting and related geologic processes, including variations in sediment accumulation rate. Early carbonate cements preserve pre-compaction …


An Implementation Of Controller Area Network Bus Analyzer Using Microblaze And Petalinux, Tung-Hsun Tsou Aug 2013

An Implementation Of Controller Area Network Bus Analyzer Using Microblaze And Petalinux, Tung-Hsun Tsou

Masters Theses

This paper presents a controller area network (CAN) monitor system created in a Field-Programmable Gate Array (FPGA) board, which is Xilinx SP605. The goals of this research are to let the system demonstrate a reliable CAN bus monitor system, and to show the Xilinx MicroBlaze and PetaLinux design flow. This system can be used to observe the CAN bus messages by means of C program and embedded Linux environment.

A Xilinx MicroBlaze soft processor is used to read CAN information from the external CAN bus controller, Microchip MCP2515. Two implementations, a stand-alone system and a Linux system, are built to …


Using Soil Organic Matter As An Iron Chelate To Enhance The Efficiency Of Modified Fenton Oxidition Of Diesel Fuel In Arctic Soils, Mary K. Sherwood Aug 2013

Using Soil Organic Matter As An Iron Chelate To Enhance The Efficiency Of Modified Fenton Oxidition Of Diesel Fuel In Arctic Soils, Mary K. Sherwood

Masters Theses

Laboratory experiments were conducted to investigate the use of modified fenton chemistry on the treatment of three soils from the Canadian arctic, all with abundant soil organic matter, iron and manganese oxides, and diesel fuel contamination. The purpose of these studies was to (I) to assess modified fenton chemistry as a treatment option for petroleum-contaminated arctic soils, and (2) to evaluate the impact of soil organic matter on the modified fenton treatment of soils. Modified fenton treatment was compared for reactions in which ethylenediaminetetraacetate was added as a chelate vs. reactions in which the native soil organic matter was the …


Activated Carbon Preconditioning To Reduce Contaminant Leaching In Cement-Based Stabilization Of Soils, Renee Elizabeth Crane Aug 2013

Activated Carbon Preconditioning To Reduce Contaminant Leaching In Cement-Based Stabilization Of Soils, Renee Elizabeth Crane

Masters Theses

Powdered activated carbon (PAC) is often added with cement to enhance the stabilization and solidification (S/S) of materials contaminated with organic compounds. Adsorption of organic contaminants onto PAC can reduce leaching of organic contaminants. Simultaneous addition of PAC and cement reduces soil handling costs, but cement hydration reactions coat PAC with Ca(OH)2 before contaminants can be adsorbed onto PAC. Laboratory studies were done on four aged, contaminated soils from manufactured gas plant sites to compare the performance of S/S treatment with simultaneous addition of PAC and cement vs. cement addition after preconditioning with PAC to enhance contaminant adsorption. Performance was …


Surface Complexation Modeling Of Cr(Vi) Absorption On Mineral Assemblages, Ann M. Gilchrist Aug 2013

Surface Complexation Modeling Of Cr(Vi) Absorption On Mineral Assemblages, Ann M. Gilchrist

Masters Theses

Hexavalent chromium (Cr(VI)) is a waste product of many anthropogenic processes. Because it is highly mobile, the improper disposal of Cr(VI) has caused widespread contamination. Because reduction and adsorption reactions may reduce the bioavailability and mobility of Cr(VI) in environmental systems, a better understanding of Cr(VI) adsorption behavior will improve remediation efforts.

Subsurfaces and soils are heterogeneous, however most studies focus on single sorbate/sorbent interactions to develop surface complexation models (SCM) for prediction of heavy metal adsorption. Theoretically, combining the SCMsdeveloped for single sorbate/sorbent systems should yield accurate predictions of adsorption in more complex systems (i.e., the component additivity approach …


Study Of Feasability For Phase Difference Extraction Using Software Defined Radio In Location Analysis, Paul Miller Aug 2013

Study Of Feasability For Phase Difference Extraction Using Software Defined Radio In Location Analysis, Paul Miller

Masters Theses

Here is a method for using the phase of an HF radio signal for use in location analysis. This computation is implemented in a software defined radio processing block in the GNU Radio environment. The signals analyzed are received by an Ettus Research USRP SDR. We created a phase analysis system called WMU Rootsync, which compares the roots of a received signal to the roots of a generated reference signal for the phase analysis. This research describes a prototype method for phase analysis only. Future projects may use these ideas differently than presented here. We intend for future projects to …


The Geology Of The South Antelope Pass Area Of The Southern Peloncillo Mountains, Hidalgo County, New Mexico, John A. Yellich Jun 2013

The Geology Of The South Antelope Pass Area Of The Southern Peloncillo Mountains, Hidalgo County, New Mexico, John A. Yellich

Masters Theses

Volcanic activity during the middle and late Tertiary has been recorded in the mountain ranges of the southwestern United States and northern Mexico and the two provinces of prominent volcanic activity, the Sierra Madre Occidental and the Mogollon Plateau, dominantly rhyolitic in composition, are connected by the Peloncillo Range. The predominant rock chemistry of the south Antelope Pass area is “rhyolitic”; however, lava rock types dominate over welded tuff rock types of the two provinces. There is a limited pre-Tertiary rock record of limestones and sandstones in the northeastern part of the study area. The rest of the study area …


Theoretical Modeling Of Near-Threshold Shape Resonance Behaviour In Photodetachment Experiments, Laurentiu Dan Dumitriu Jun 2013

Theoretical Modeling Of Near-Threshold Shape Resonance Behaviour In Photodetachment Experiments, Laurentiu Dan Dumitriu

Masters Theses

This thesis attempts to better understand the results obtained from photodetachment experiments of Fe-, made by the Western Michigan University experimental atomic physics group at the Advanced Light Source (ALS), Lawrence Berkeley National laboratory.

After a relevant description of the quantum mechanics and theoretical atomic physics concepts and formulas involved in this subject, a physically realistic model, based on the square well potential, is developed. Based on this model, the theoretical photodetachment cross section is computed in order to reproduce the qualitative behavior of the experimental photodetachment cross section measured at ALS.

This development, involving programming in Fortran and numerical …


The Fine-Tuning Of Nomic Behavior In Multiverse Scenarios, Max Lewis Edward Andrews May 2013

The Fine-Tuning Of Nomic Behavior In Multiverse Scenarios, Max Lewis Edward Andrews

Masters Theses

The multiverse hypothesis (the view that there is not just one world or universe in existence, bur rather that there are many) is the leading alternative to the competing fine-tuning hypothesis (the laws of physics and constants are fine-tuned for the existence of life). The multiverse dispels many aspects of the fine-tuning argument by suggesting that there are different initial conditions in each universe, varying constants of physics, and the laws of nature lose their known arbitrary values; thus, making the previous single-universe argument from fine- tuning incredibly weak. The position that will be advocated will be that a form …


Analysis Of Depositional Facies And Geological Controls On Reservoir Quality In Lower-Middle Devonian Sylvania Sandstone, Midland County, Michigan, Katherine A. Pollard Apr 2013

Analysis Of Depositional Facies And Geological Controls On Reservoir Quality In Lower-Middle Devonian Sylvania Sandstone, Midland County, Michigan, Katherine A. Pollard

Masters Theses

The early-Middle Devonian Sylvania “Sandstone” is considered a target for potential CO2 geosequestration. In order to develop geostatic models for CO2 injection simulations, controls on reservoir properties must be addressed. The three objectives of this study involve: 1) develop an overview of depositional lithofacies and their vertical stacking relationships, 2) determine fluid sources and controls of diagenesis (dolomitization and silicification), and 3) examine geological controls on the distribution and character of reservoir facies.

The grossly transgressive Sylvania-Bois Blanc interval is a complex lithologic assemblage. Sylvania “Sandstone” strata transition from high energy, subtidal to lower-intertidal mixed carbonate-siliciclastic facies to …


Late Mississippian (Chesterian) Through Early Pennsylvanian (Atokan) Strata, Michigan Basin, U.S.A., Shannon M. Towne Apr 2013

Late Mississippian (Chesterian) Through Early Pennsylvanian (Atokan) Strata, Michigan Basin, U.S.A., Shannon M. Towne

Masters Theses

Over 2,000 linear feet of core material was analyzed to evaluate the stratigraphy and basin evolution of Carboniferous strata in the Michigan basin. Rock units were evaluated on the basis of lithofacies type, contact relationships, and existing regional geologic interpretations. The recovery of three distinct pollen and spore assemblages from core confirms the timing of deposition during the Late Mississippian Chesterian and Early-Middle Pennsylvanian Morrowan and Atokan regional stages within the Michigan basin.

The deposition of a marine carbonate succession with significant interstratified quartz sandstone occurred during the Chesterian regional stage. The Bayport interval (Bayport Limestone) is composed of seven …


Adsorption Of Hexavalent Chromium On Hydrous Manganese Oxide, Andrew K. Macleod Apr 2013

Adsorption Of Hexavalent Chromium On Hydrous Manganese Oxide, Andrew K. Macleod

Masters Theses

Hexavalent chromium is a very common contaminant most often associated with industrial processes, it is quite mobile in the subsurface and a better understanding of its mobility and interactions with soil constituents will help ongoing remediation efforts.

Hydrous manganese oxides (HMO) are a very common soil constituent and thus would be likely to interact with Cr(VI) in contaminated shallow subsurface environments. The goal of this study is to develop a working model that can improve predictions of Cr(VI) mobility in natural systems. A diffuse double layer surface complexation model (DLM) was developed by deriving reaction stoichiometries and stability constants for …