Engineering Commons^™

The Role Of Nitrification And Denitrification In Successful Cultivation Of Oxygenic Photogranules For Wastewater Treatment, Kristie Stauch-White

Environmental & Water Resources Engineering Masters Projects

Oxygenic photogranules (OPGs) are compact, spherical, self-immobilizing biofilms in the form of dense aggregates of microorganisms with a predomination of filamentous cyanobacteria cultivated from photoilluminated activated sludge. In this study, aerobic and anaerobic nitrogen transformation processes occurring simultaneously within OPGs, during both successful and unsuccessful cultivations, were examined. Chemical analyses including ammonium, nitrate, and nitrite concentrations at the beginning and periodically during OPG cultivations indicated nitrogen transformations occurring during successful cultivations. Additionally, qPCR studies revealed that successful cultivations supported a greater relative abundance of cyanobacteria, nitrifying, and denitrifying populations during the cultivation period. Dissolved oxygen microprofiles within a successfully cultivated …

Analyzing Streamflow Forecasts In The Context Of System Performance: A Case Study Of The City Of Baltimore Water Supply, Alexandra Mcintyre

Environmental & Water Resources Engineering Masters Projects

A major challenge confronting water suppliers is how to best incorporate emerging forecasting technologies into their drought management operations. The need for drought plans that make use of proactive drought mitigation actions is particularly pressing as climate change is expected to cause more frequent and severe droughts in the near future. This research evaluates streamflow forecast skill in the context of drought planning. The City of Baltimore’s water supply system serves as a case study. Forecasts generated by the National Oceanic and Atmospheric Administration (NOAA) and the National Weather Service’s Middle Atlantic River Forecast Center (MARFC) are integrated into a …

Drought Management Using Streamflow Forecasts: A Case Study Of The City Of Baltimore Water Supply, Kathryn Booras

Environmental & Water Resources Engineering Masters Projects

This research investigates forecast skill in predicting the onset and severity of drought in the Susquehanna River Basin. Streamflow forecasts developed by the National Oceanic and Atmospheric Administration’s (NOAA’s) Mid-Atlantic River Forecast Center (MARFC) are incorporated with other key drought indices in an aggregate drought index to predict and classify drought severity and to trigger drought mitigation actions. Climate drought index parameters for the Susquehanna River Basin, such as the Standardized Precipitation Index (SPI), Days of Storage Remaining Index (DSR), and Palmer Drought Severity Index (PDSI), are evaluated by their ability to detect water supply droughts of record. Drought indicators …

Biogenic Organic Carbon Compounds In Air And Rain, Iman Hosseini Shakib

Environmental & Water Resources Engineering Masters Projects

Rainwater quality has not been an issue of concern until recent decades of increasing urbanization and industrialization. Therefore, the role of biogenic contamination sources has been always underestimated as generally, anthropogenic contaminants are thought to be responsible for rainwater quality deterioration. This study aims to find the sources and reasons of biogenic VOC emission into the air and their changes in the air. Also, transfer of biogenic VOCs into the rainwater and their abundance have been investigated. The effects of these biogenic VOCs on rainwater quality have been studied by sampling of two rain events in the University of Massachusetts …

Assessing The Economic And Flow Regime Outcomes Of Alternative Hydropower Operations On The Connecticut River's Mainstem, Luke Detwiler

Environmental & Water Resources Engineering Masters Projects

Hydropower provides a source of reliable and inexpensive energy, producing approximately 20% of the global energy supply, though it comes at a cost to riverine ecosystems. To maximize revenues, major hydropower facilities store and release water with respect to short-term changes in energy price, causing significant sub-daily flow regime alterations that impact downstream ecological communities. In the United States, the Federal Energy Regulatory Commission (FERC) is responsible for hydropower regulation and this is administered, in part, during periodic relicensing of existing facilities. The process of relicensing provides the opportunity to evaluate the goals and concerns of interested parties and evaluate …

Investigating Interactions Between Water And Society On A Global Scale: Econometric Analyses Of Hydroclimatic Variability And Water Policy, Hassan Furqan Khan

Environmental & Water Resources Engineering Masters Projects

INVESTIGATING INTERACTIONS BETWEEN WATER AND SOCIETY ON A GLOBAL SCALE: ECONOMETRIC ANALYSES OF HYDROCLIMATIC VARIABILITY AND WATER POLICY AUGUST 2016 HASSAAN FURQAN KHAN Directed by: Professor Casey M. Brown Water-related hazards such as floods, droughts and disease cause damage to an economy through the destruction of physical capital including property and infrastructure, the loss of human capital and the interruption of economic activities, like trade and education. The question for policy makers, however, is whether the impacts of water-related risk accrue to manifest as a drag on economic growth at a scale suggesting policy intervention. In this work, we use …

Hydrologic Modeling At Ungauged Locations In Support Of The Development Of A Vulnerability Ranking Protocol System For Road-Stream Crossing Infrastructure, Gordon Clark

Environmental & Water Resources Engineering Masters Projects

Recent tropical storms that have resulted in flood events with large economic impacts in the Northeastern US have catalyzed efforts to understand the complex interactions between human and natural systems. Specifically, the resilience of our transportation infrastructure to climate and the impact of our transportation systems on the aquatic environment are of significant interest on both the local and regional scales to state and federal agencies. It is important that new, innovative approaches be developed that consider both the robustness of our infrastructure today and its ability to cope with forecasted extremes due to climate change. Because few streams are …

Understanding Factors That Affect Microbial Fuel Cell Performance: Inoculum Characteristics And Methanogenesis, Joshua Jack

Environmental & Water Resources Engineering Masters Projects

Microbial fuel cells (MFCs) are a promising approach to wastewater treatment that use anode-respiring bacteria (ARB) to oxidize organic matter and generate electric current. Although these devices have great potential, MFCs are not yet commercialized primarily due to their low power output at pilot scale. Past studies have hypothesized power production may be largely limited by high internal resistances and competing microbial metabolisms (Logan et al., 2008).

The source of inoculum used to build MFC communities has been demonstrated to significantly influence cell resistance and microbial dynamics (Sun et al., 2008; Chae et al., 2008). Studies that have shown these …

Aging And Property Changes Of Clay Around Driven Piles, Hasian R. Zapata

Geotechnical Engineering Masters Projects

The purpose of this research was to determine how soil disturbance caused by the installation of piles (of differing types and geometries) in clay affect the short and long-term capacity of piles. Several types of piles were installed in lightly overconsolidated clay at three different test sites in Amherst, Massachusetts. Before and after pile installation, an in-situ testing program consisting of field vane shear tests was carried out around piles installed at one of the three testing sites. Undrained shear strength and water content profiles allowed for an approximate determination of changes in the behavior of the clay surrounding some …

Patterns Around Us Presentation, Benny Davidovitch

Patterns Around Us

No abstract provided.

Evaluating Roadway Cross-Sectional Design Elements And Its Impact On Driver Behavior Using A Driving Simulator, Bhavana Gongalla

Transportation Engineering Masters Projects

This research explores the relationship between the cross-sectional design elements and the impact on selected driver attributes such as speed profiles and lateral positioning. In this experiment a traditional collector type base roadway of 1.5 miles with 14 ft travel lane and 8 ft shoulder was modeled using a fixed base driving simulator. The base scenario was subsequently reconfigured with four different cross-sectional design with various elements within the same physical right-of-way. Specific design elements included, narrower lanes, bicycle lanes, raised center median and a curvilinear roadway profile. A within subject’s design of twenty participants who drove each of the …

Functional Droplets That Recognize, Collect, And Transport Debris On Surfaces, Ying Bai, Chia-Chih Chang, Umesh Choudhary, Irem Bolukbasi, Alfred J. Crosby, Todd Emrick

Polymer Science and Engineering Department Faculty Publication Series

We describe polymer-stabilized droplets capable of recognizing and picking up nanoparticles from substrates in experiments designed for transporting hydroxyapatite nanoparticles that represent the principal elemental composition of bone. Our experiments, which are inspired by cells that carry out materials transport in vivo, used oil-in-water droplets that traverse a nanoparticle-coated substrate driven by an imposed fluid flow. Nanoparticle capture is realized by interaction of the particles with chemical functionality embedded within the polymeric stabilizing layer on the droplets. Nanoparticle uptake efficiency is controlled by solution conditions and the extent of functionality available for contact with the nanoparticles. Moreover, in an elementary …

Quantifying As Path Inflation By Routing Policies, Qixin Gao, Feng Wang, Lixin Gao

Electrical and Computer Engineering Faculty Publication Series

A route in the Internet may take a longer AS path than the shortest AS path due to routing policies. In this paper, we systematically analyze AS paths and quantify the extent to which routing policies inflate AS paths. The results show that AS path inflation in the Internet is more prevalent than expected. We first present the extent of AS path inflation observed from the RouteView and RIPE routing tables. We then employ three common routing policies to show the extent of AS path inflation. We find that No-Valley routing policy causes the least AS path inflation among the …

The Predictive Link Between Matrix And Metastasis, Lauren E. Barney, Lauren Jansen, S. R. Polio, Sualyneth Galarza, Maureen E. Lynch, Shelly Peyton

Chemical Engineering Faculty Publication Series

Cancer spread (metastasis) is responsible for 90% of cancer-related fatalities. Informing patient treatment to prevent metastasis, or kill all cancer cells in a patient's body before it becomes metastatic is extremely powerful. However, aggressive treatment for all non-metastatic patients is detrimental, both for quality of life concerns, and the risk of kidney or liver-related toxicity. Knowing when and where a patient has metastatic risk could revolutionize patient treatment and care. In this review, we attempt to summarize the key work of engineers and quantitative biologists in developing strategies and model systems to predict metastasis, with a particular focus on cell …

Voltage Divider Effect For The Improvement Of Variability And Endurance Of Taox Memristor, Kyung Min Kim, J. Joshua Yang, John Paul Strachan, Emmanuelle Merced Grafals, Ning Ge, Noraica Davila Melendez, Zhiyong Li, R. Stanley Williams

Electrical and Computer Engineering Faculty Publication Series

The impact of a series resistor (RS) on the variability and endurance performance of memristor was studied in the TaOx memristive system. A dynamic voltage divider between the RS and memristor during both the set and the reset switching cycles can suppress the inherent irregularity of the voltage dropped on the memristor, resulting in a greatly reduced switching variability. By selecting the proper resistance value of RS for the set and reset cycles respectively, we observed a dramatically improved endurance of the TaOx memristor. Such a voltage divider effect can thus be critical for the memristor applications that require low …

Complex Coacervate-Based Materials For Biomedicine, Sarah L. Perry, Whitney C. Blocher

Chemical Engineering Faculty Publication Series

There has been increasing interest in complex coacervates for deriving and trans- porting biomaterials. Complex coacervates are a dense, polyelectrolyte-rich liq- uid that results from the electrostatic complexation of oppositely charged macroions. Coacervates have long been used as a strategy for encapsulation, par- ticularly in food and personal care products. More recent efforts have focused on the utility of this class of materials for the encapsulation of small molecules, pro- teins, RNA, DNA, and other biomaterials for applications ranging from sensing to biomedicine. Furthermore, coacervate-related materials have found utility in other areas of biomedicine, including cartilage mimics, tissue culture scaffolds, …

A Simple One-Scale Constitutive Model For Static Liquefaction Of Sand-Silt Mixtures, Yang Liu, Ching-Shung Chang, Shun-Chuan Wu

Civil and Environmental Engineering Faculty Publication Series

Instability of liquefaction is one of the major reasons which results in the failure of earth structure such as dam. The present study focuses on the simulation of static liquefaction behavior for granular materials such as sand and sand-silt mixtures. Based on micromechanical analysis of inter-particle behavior, a simple one-scale model is proposed to simulate the stress-strain response of sand; then the proposed model is extended to simulate the sand-silt mixtures using the mixture theory combining the properties of sand and silt according to their proportions. Empirical expressions are introduced to fit the critical state strength and the location of …

Generating Optimal Control Simulations Of Musculoskeletal Movement Using Opensim And Matlab, Leng-Feng Lee, Brian R. Umberger

Kinesiology Department Faculty Publication Series

Computer modeling, simulation and optimization are powerful tools that have seen increased use in biomechanics research. Dynamic optimizations can be categorized as either data-tracking or predictive problems. The data-tracking approach has been used extensively to address human movement problems of clinical relevance. The predictive approach also holds great promise, but has seen limited use in clinical applications. Enhanced software tools would facilitate the application of predictive musculoskeletal simulations to clinically-relevant research. The open-source software OpenSim provides tools for generating tracking simulations but not predictive simulations. However, OpenSim includes an extensive application programming interface that permits extending its capabilities with scripting …

A Comparison Of The Elastic Properties Of Graphene- And Fullerene-Reinforced Polymer Composites: The Role Of Filler Morphology And Size, Chang-Tsan Lu, Asanka Weerasinghe, Dimitrios Maroudas, Ashwin Ramasubramaniam

Mechanical and Industrial Engineering Faculty Publication Series

Nanoscale carbon-based fillers are known to significantly alter the mechanical and electrical properties of polymers even at relatively low loadings. We report results from extensive molecular-dynamics simulations of mechanical testing of model polymer (high-density polyethylene) nanocomposites reinforced by nanocarbon fillers consisting of graphene flakes and fullerenes. By systematically varying filler concentration, morphology, and size, we identify clear trends in composite stiffness with reinforcement. To within statistical error, spherical fullerenes provide a nearly size-independent level of reinforcement. In contrast, two-dimensional graphene flakes induce a strongly size-dependent response: we find that flakes with radii in the 2–4 nm range provide appreciable enhancement …

Evaluation Of A Scalable Information Analytics System For Enhanced Situational Awareness In Mass Casualty Events, Aura Ganz, James M. Schafer, Zhuorui Yang, Jun Yi, Graydon Lord, Gregory Ciottone

Electrical and Computer Engineering Faculty Publication Series

We investigate the utility of DIORAMA-II system which provides enhanced situational awareness within a disaster scene by using real-time visual analytics tools and a collaboration platform between the incident commander and the emergency responders. Our trials were conducted in different geographical areas (feature-rich and featureless regions) and in different lighting conditions (daytime and nighttime). DIORAMA-II obtained considerable time gain in efficiency compared to conventional paper based systems. DIORAMA-II time gain was reflected in reduction of both average triage time per patient (up to 34.3% average triage time reduction per patient) and average transport time per patient (up to 76.3% average …

Robust Identification Of Dynamically Distinct Regions In Stratified Turbulence, Gavin D. Portwood, Stephen M. De Bruyn Kops, J. R. Taylor, H. Salehipour, C. P. Caulfield

Mechanical and Industrial Engineering Faculty Publication Series

we present a new robust method for identifying three dynamically distinct regions in a stratified turbulent flow, which we characterise as quiescent flow, intermittent layers, and turbulent patches. The method uses the cumulative filtered distribution function of the local density gradient to identify each region. We apply it to data from direct numerical simulations of homogeneous stratified turbulence, with unity Prandtl number, resolved on up to 8192x8192x4092 grid points. In addition to classifying regions consistently with contour plots of potential enstropy, our method identifies quiescent regions as regions where ∊ ⁄ νΝ² ~ Ο(1), layers as regions where …

Linear Viscoelasticity Of Complex Coacervates, Yalin Liu, H. Henning Winter, Sarah L. Perry

Chemical Engineering Faculty Publication Series

Rheology is a powerful method for materials characterization that can provide detailed information about the self-assembly, structure, and intermolecular interactions present in a material. Here, we review the use of linear viscoelastic measurements for the rheological characterization of complex coacervate-based materials. Complex coacervation is an electrostatically and entropically-driven associative liquid-liquid phase separation phenomenon that can result in the formation of bulk liquid phases, or the self-assembly of hierarchical, microphase separated materials. We discuss the need to link thermodynamic studies of coacervation phase behavior with characterization of material dynamics, and provide parallel examples of how parameters such as charge stoichiometry, ionic …

Graphene-Based Microfluidics For Serial Crystallography, Shuo Sui, Yuxi Wang, Kristopher W. Kolewe, Vukica Srajer, Robert Henning, Jessica D. Schiffman, Christos Dimitrakopoulos, Sarah L. Perry

Chemical Engineering Faculty Publication Series

Microfluidic strategies to enable the growth and subsequent serial crystallographic analysis of micro-crystals have the potential to facilitate both structural characterization and dynamic structural studies of protein targets that have been resistant to single-crystal strategies. However, adapting microfluidic crystallization platforms for micro-crystallography requires a dramatic decrease in the overall device thickness. We report a robust strategy for the straightforward incorporation of single-layer graphene into ultra-thin microfluidic devices. This architecture allows for a total material thickness of only ∼1 μm, facilitating on-chip X-ray diffraction analysis while creating a sample environment that is stable against significant water loss over several weeks. We …

Metabolic Modeling Of A Chronic Wound Biofilm Consortium Predicts Spatial Partitioning Of Bacterial Species, Poonam Phalak, Jin Chen, Ross P. Carlson, Michael A. Henson

Chemical Engineering Faculty Publication Series

Background

Chronic wounds are often colonized by consortia comprised of different bacterial species growing as biofilms on a complex mixture of wound exudate. Bacteria growing in biofilms exhibit phenotypes distinct from planktonic growth, often rendering the application of antibacterial compounds ineffective. Computational modeling represents a complementary tool to experimentation for generating fundamental knowledge and developing more effective treatment strategies for chronic wound biofilm consortia.

Results

We developed spatiotemporal models to investigate the multispecies metabolism of a biofilm consortium comprised of two common chronic wound isolates: the aerobe Pseudomonas aeruginosa and the facultative anaerobe Staphylococcus aureus. By combining genome-scale metabolic …

Polyelectrolyte-Functionalized Nanofiber Mats Control The Collection And Inactivation Of Escherichia Coli, Katrina A. Rieger, Michael Porter, Jessica D. Schiffman

Chemical Engineering Faculty Publication Series

Quantifying the effect that nanofiber mat chemistry and hydrophilicity have on microorganism collection and inactivation is critical in biomedical applications. In this study, the collection and inactivation of Escherichia coli K12 was examined using cellulose nanofiber mats that were surface-functionalized using three polyelectrolytes: poly (acrylic acid) (PAA), chitosan (CS), and polydiallyldimethylammonium chloride (pDADMAC). The polyelectrolyte functionalized nanofiber mats retained the cylindrical morphology and average fiber diameter (~0.84 µm) of the underlying cellulose nanofibers. X-ray photoelectron spectroscopy (XPS) and contact angle measurements confirmed the presence of polycations or polyanions on the surface of the nanofiber mats. Both the control cellulose and …