Digital Commons Network^™

Microbial Competition In Bioelectrochemical Systems, Varun Srinivasan

Doctoral Dissertations

Bioelectrochemical systems(BESs)/ microbial fuel fells (MFCs) are a well-studied potential technology for bioremediation and decentralized wastewater treatment. However, progress has been somewhat stalled at the bench-scale. In well controlled experiments electron recovery is high. In natural environments, wastewaters are complex and anode-respiring bacteria can be outcompeted in the presence of competing microorganisms, leading to a loss in electron-recovery and power production. Furthermore, the cathode of the MFC plays a vital role in providing flexibility for treatment options but is an understudied part of MFCs. Modelling Intracellular Competition in a Denitrifying Biocathode: One potential MFC configuration uses an organic-oxidizing anode biofilm …

Modeling Performance, Cost, Delivery, And Trip Distribution Of Demand Responsive Transit Systems With Zoning, Mahour Rahimi

Doctoral Dissertations

Demand responsive transit (DRT) services are expensive to operate, so it is crucial to understand the factors that drive the agency costs and be able to investigate and predict the effect of possible changes in specific operating parameters as well as demand and service coverage areas on total costs. In this research, we adopt the concept of the analytical model proposed by Daganzo (1978) to present continuum approximation (CA) models that can estimate important service related factors. As the first step, we propose three analytical models to approximate the operation related variables of DRT services; Fleet Size, Vehicle Hours Traveled …

Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel

Doctoral Dissertations

A uniform dispersion of reactants is necessary to achieve a complete reaction involving multi-components, especially for the crosslinking of rigid high-performance materials. In these reactions, miscibility is crucial for curing efficiency. This miscibility is typically enhanced by adding a third component, a plasticizer. For the reaction of the highly crystalline crosslinking agent hexamethylenetetramine (HMTA) with a strongly hydrogen-bonded phenol formaldehyde resin, furfural has been traditionally used as the plasticizer. However, the reason for its effectiveness is not clear. In this doctoral thesis work, miscibility and crosslinking efficiency of plasticizers in phenolic curing reactions are studied by thermal analysis and spectroscopic …

Decision Analytical Methods For Robust Water Infrastructure Planning Under Deep Uncertainty, Mehmet Umit Taner

Doctoral Dissertations

Deep uncertainties resulting from climate change, demographic pressures, and rapidly evolving socioeconomic conditions are challenging the way that water planners design and operate large-scale infrastructure systems. Conventionally, water infrastructures have been developed using stationary methods, assuming that the underlying uncertainties can be derived from historical data or experience. However, these methods are less useful under deeply uncertain climate and socioeconomic conditions, in which the future can be substantially different from the past and cannot be expressed by well-defined probability distributions. The recognition of deep uncertainties in long-term water resources planning has led to the development of “decision-analytical” frameworks that do …

Microbial Dynamics And Design Considerations For Decentralized Microbial Fuel Cell Applications, Cynthia Castro

Doctoral Dissertations

The purpose of this dissertation was to assess the practicality of using microbial fuel cells (MFCs) as alternative sanitation systems for wastewater treatment and energy recovery, focusing on identifying key design considerations for treating high strength wastewater and managing alternative metabolic pathways. We evaluated the energetic outputs of a lab-based pilot MFC designed to treat complex organics present in both synthetic feces and municipal wastewater. The pilot MFC produced two energetic products, methane and electricity, when treating two types of complex wastewaters. The energetic products associated with anode respiration and methanogenesis were simultaneously observed and yielded a combined energy ouput …

Qkan - Management Of Drainage System Data With Qgis, Jörg Höttges

Free and Open Source Software for Geospatial (FOSS4G) Conference Proceedings

Based on QGIS a database structure and a set of plugins have been developed to improve the workflow for the hydraulic design of urban drainage systems for consulting engineers. The main goal is pre- and postprocessing in combination with various commercial hydraulic simulation software packages. The plugins provide import and export functionalities, simulation result viewing and generation of longitudinal cross sections in a CAD program. All modules make intensive use of SQL based spatial functions instead of functions implemented in QGIS, because of their stability, higher flexibility and speed due to the indexing functionality. On the other hand the database …

Performance Of Adhesive And Cementitious Anchorage Systems, Mirna Mendoza

Masters Theses

Post-installed anchoring systems are used extensively in Massachusetts Department of Transportation (MassDOT) projects due their ease of attachment to existing structures. However, recommendations on materials from various manufacturers are currently lacking for certain situations such as long-term tension loading. The purpose of the investigation presented in this thesis was to provide guidance on the use of anchoring systems to MassDOT. This research project evaluated the behavior of adhesive and cementitious bonded anchoring systems per the Stress-versus-Time-to-Failure approach found in the provisional standard AASHTO TP-84 in order to provide recommendations pertaining to the test method. Supplemental short-term anchor pullout tests were …

Development Of High Early-Strength Concrete For Accelerated Bridge Construction Closure Pour Connections, Stephanie Castine

Masters Theses

Accelerated bridge construction (ABC) has become a popular alternative to using traditional construction techniques in new bridge construction and existing bridge deck replacement because of the reduction of time spent in field activities. A key feature of bridges built using ABC techniques is the extensive use of prefabricated components. Prefabricated components are joined in the field using small volume closure pours involving high performance materials (steel and concrete) to ensure adequate transfer of forces between components. To date, the materials developed for closure pours have been based on proprietary components, so a need has arisen for development of mixes that …

Evaluating Variances Between Departments Of Transportation In New England To Create A Strategic Transportation Workforce, Chelsea Bouchard

Masters Theses

As the baby boomer generation approaches retirement, the transportation workforce is increasingly under strain. Employees are exiting the industry in larger volumes than incoming hires; which is creating a need to reevaluate and revamp work processes. In addition, the industry is transitioning into the 21st century and that is requiring the adaptation of new technologies. The gap between old and new employee skills is growing and seen throughout the industry. There is a growing need and opportunity to develop a new set of job competencies which create job specifications and job postings, which support the organization’s strategic plan. In this …

Evaluation Of New England Bridges For Bat Roosting Including Methodology And Case Studies, Angela Berthaume

Masters Theses

Bats are known and documented to use bridge structures as roosts in various locations throughout the United States and abroad, but there is limited knowledge of how bats use bridges in New England. Significant population declines due to White-Nose Syndrome have resulted in several bat species being listed as state or federally threatened or endangered. If bats are using bridges as roosts, significant effort is required to ensure they are not disturbed or harmed during construction or maintenance work, requiring knowledge of assessment methods to identify likely roost locations in bridges. This thesis describes a two summer study evaluating the …

An Evaluation Of Traffic Control Devices And Driver Distraction On Driver Behavior At Railway-Highway Grade Crossings, Radhameris A. Gomez Gabriel

Doctoral Dissertations

At-grade crossings (grade crossings) are those crossings in which any part of a roadway intersects with railroad tracks. Safety at these railroad-highway grade crossings is a major concern, with traffic control warning devices serving as the main mechanisms for improving safety. There are three factors that influence a driver’s behavior at a given crossing. First, traffic control devices, including warning devices at the railroad-highway grade crossings, provide the driver with information whose impact will depend in part on the likelihood that the driver knows whether to glance in the direction of the device based on prior experience, and in part …

Modeling And Modifying Day-To-Day Travel Behaviors: Empirical Results And Methodological Advances, Yue Tang

Doctoral Dissertations

The increasing availability of individual-level longitudinal data provides the opportunity to better understand travelers'\ day-to-day learning process of their choice alternatives, which enables potentially more accurate predictions of choice patterns in a network with uncertainties. In this thesis, an instance-based learning (IBL) model for travel choice is developed within route-choice context, where on each day a traveler's decision depends on her entire choice history in the past. Learning in this model is based on the power law of forgetting and practice, which is shown to be capable of capturing various psychological effects embedded in travelers'\ day-to-day learning process, including the …

Multi-Criteria Decision Making When Planning Sustainable Multimodal Transportation Routes In A Linear Corridor, Marie Louis

Doctoral Dissertations

In urban and suburban locations, public transit can be seen as an effective mode of daily transportation. The majority of the time, travelers would seek the cheapest, shortest, and possibly most eco-friendly means of transit. When designing public transit network systems, transportation planners and decision-makers, with input from stakeholders, should strive to optimize transportation services to meet the needs of the population most efficiently and at the lowest cost, that is, providing a transportation system that s the three E's of the sustainability concept: environment, social equity, and economic. Previous studies have focused on sustainability as the primary concern in …

Restoring Floodplains In The Connecticut River Basin: A Flood Management Strategy, Abigail Ericson

Environmental & Water Resources Engineering Masters Projects

This research investigates how changes to floodplains in the Connecticut River Basin impact flood events. Climate impacted flows and increased development within the floodplain could lead to worsening flood events and less habitat availability for threatened species. Potential future conditions are evaluated through a wide range of scenarios to assess the range of possible impacts using a HEC-RAS 2D model. Three different flood events, 1-yr, 10-yr, and 100-yr, are evaluated for each scenario. Five metrics, Discharge, Depth, Time of Arrival, Flooding Duration, and Number of Buildings Flooded, are tracked for each scenario. These metrics are compared to select the ideal …

Robust Drought Planning In Megacities: A Case Study In São Paulo, Brazil, Grace Cambareri

Environmental & Water Resources Engineering Masters Projects

The megacity of São Paulo, Brazil recently faced a severe three-year drought (2013- 2015) that highlighted the challenges of growing water demands, unpredictability of future supply, and proper communication with the public during crisis. Given the poor outcomes of the recent drought, the question remains as to how the drought can be used to inform and improve future drought preparedness. This study develops a seven-step framework using simulation and a computational search to identify promising drought plans based on the historic record. These promising plans are then tested under alternative states of the world to explore their robustness and identify …

Pilot Reactor Operation Of The Oxygenic Photogranule (Opg) Wastewater Treatment Process, Adam Matthew Mcnair

Environmental & Water Resources Engineering Masters Projects

Treating wastewater is imperative for maintaining public health and sanitation as well as the natural environment. In the United States and developed countries around the globe, the activated sludge (AS) process has been paramount in effectively treating wastewater for over a century. However, high energy consumption due to required mechanical aeration of AS limits its potential as a sustainable process. The oxygenic photogranule (OPG) wastewater treatment process utilizes the photosynthetic ability of OPGs made possible by the symbiosis between heterotrophic AS and filamentous cyanobacteria and algae in dense, spherical biogranules. This research presents pilot operation of the OPG wastewater treatment …

I. The High Strain Rate Response Of Hollow Sphere Steel Foam; Ii. The Dynamic Response Of An American Elm Tree, Ignacio Cetrangolo

Masters Theses

PART I

Hollow-sphere (HS) steel foam is a relatively new material whose cellular morphology and material properties qualify it as a metallic foam. This is an innovative foam-like material that exhibits high stiffness paired with low relative densities. Technological advancements in the past few decades have enabled the manufacturing of this material by a sintering process and, as a result, research has begun to accelerate as a multi-school collaboration effort for this particular work. Even though commercialization has been a challenge for metallic foams, it is imperative that researchers continue to prove and promote the advantages of metallic foams despite …

Methods For Incorporating Ecological Impacts With Climate Uncertainty To Support Robust Flood Management Decision-Making, Caitlin M. Spence

Doctoral Dissertations

Modern and historic flood risk management involves accommodating multiple sources of sources of uncertainty and potential impacts across a broad range of interrelated sectors. Sources of uncertainty that affect planning include internal climate variability, anthropogenic changes such as land use and system performance expectations, and more recently changes in climatology that affect the resources supporting the system. Flood management systems potentially impact human settlements within and beyond the systems’ scope of planning, local weather patterns, and associated ecological systems. Federal guidelines across nations have called for greater consideration of uncertainty and impacts of water resources planning projects, but methods for …

Evaluating The Impacts Of Driver Behavior In The Speed Selection Process And The Related Outcomes, Cole D. Fitzpatrick

Doctoral Dissertations

In the United States, traffic crashes claim the lives of 30,000 people every year and is the leading cause of death for 5-24 year olds. Driver error is the leading factor in over 90 percent of motor vehicle crashes, with the roadway and the vehicle each only accounting for about 2 percent of crashes. In the United States, nearly a third of fatal crashes are due to speeding and therefore, a critical step in improving traffic safety is research aimed to reduce speeding, such as crash data analysis, outreach campaigns, targeted enforcement, and understanding speed selection. In this dissertation, a …

Evaluating The Influence Of Breakdown Fouling And Moisture Content On Mechanical And Electromagnetic Properties Of Ballasted Railroad Track, Hamed Faghihi Kashani

Doctoral Dissertations

A complete study was performed to develop correlations between electromagnetic and mechanical properties of ballast. These correlations can be used to predict the deformation properties of ballast and also its dynamic behavior under heavy axle load in different fouling and moisture conditions by GPR survey. By developing this technique and performing similar tests on different types of ballast and fouling materials, a criterion can be developed to detect the railroad high risk areas and predict the engineering properties of ballast by GPR surveys. This study was performed on granite ballast and breakdown fouling and has three phases: performing GPR survey …

Total Organic Iodine Quantification And Occurrence In Drinking Water, And Toxicity Assessment Of Iodinated Disinfection By-Products, Rassil El Sayess

Doctoral Dissertations

The focus of this work has been placed is on iodinated DBPs (I-DBPs), measured using total organic iodine (TOI), a surrogate measure of iodinated organics. This is due to the growing toxicity literature that places I-DBPs among the most toxic of all DBPs. To measure TOI in water, a new method was developed. This method combines adsorption, combustion, and trapping of combustion products, with an offline inductively coupled plasma/mass spectrometer (ICP-MS) for iodide detection. Three factors were varied across two levels each in order to optimize the method. The chosen method used a sample pH of less than 1 prior …

Seismic Behavior Of Concrete Frames With Jacketed Columns, Jose Alvarez

Doctoral Dissertations

Research on jacketed reinforced concrete (RC) columns is well established and growing. The existing studies describe the ability of jackets to rehabilitate RC columns for seismic demands. The system in the studies has proven to upgrade both strength and ductility of their unretrofitted counterparts, concentrated on repairs of deficiencies, currently in columns designed with old code provisions. These deficiencies include: low shear strength, insufficient core confinement, and short lap-splices, in particular within the plastic hinge zone. Columns with these deficiencies usually have brittle failures and cannot develop displacement ductility ( ) greater than 2. Research results on columns retrofitted with …

Effects Of Sulfidation On The Deposition And Detachment Of Silver Nanoparticles, Joseph Murphy

Environmental & Water Resources Engineering Masters Projects

The transformation of silver nanoparticles (AgNPs) due to environmental factors can play a role in their fate and transport in aquatic systems. Sulfidation has the potential to alter these particles’ physio-chemical properties and their subsequent mobilization in aquatic environments. The water chemistry (e.g. pH, dissolved organic carbon) of these systems can also change the behavior of AgNPs. To better understand the effects of sulfidation on the characteristics and deposition of AgNPs, techniques such as quartz crystal microgravimetry (QCM) and dynamic light scattering (DLS) were used. In this study, AgNPs with two different ligand types, Polyvinylpyrrolidone (PVP)-capped AgNPs (PVP-AgNPs) and Polyethylene …

Evaluation Of Disinfection Byproduct Speciation Models Based On Biodegradation And Chemical Decomposition, Xian Ma

Environmental & Water Resources Engineering Masters Projects

The USEPA has regulated both chlorinated and brominated trihalomethanes (THMs) and haloacetic acids (HAAs) since Stage 2 D/DBP Rule. Among regulated species, all four chlorinated and brominated THMs are regulated as total TTHMs (TTHM). But of the nine HAAs, only the sum of five (HAA5) are regulated, with no detail on individual species. This leaves four unregulated HAAs of which all contain bromine. With more attention on the brominated haloacetic acids due to their higher toxicity, the focus on the formation of those unregulated brominated species is elevated. The objective of this study is to assess national occurrence of all …

Investigation Of Safety At Toll Plazas Through Microsimulation And Driving Simulation Approaches, Foroogh Sadat Hajiseyedjavadi

Transportation Engineering Masters Projects

Toll plazas are one of the critical components of a roadway system for capital financing, infrastructure maintenance revenue, or traffic maintenance and congestion control strategies. At the same time, they are among the most complex road structures, as drivers are exposed to a large amount of information and have a short amount of time to make a decision. Since the advent of electronic toll collection (ETC) technology, the complexity of toll plazas has greatly increased. The objective of this study is to investigate the effect of toll plaza design and traffic conditions on drivers’ behavior and level of safety. This …

River And Stream Power Assessment Report Including Culvert And Bridge Vulnerability Analysis: Deerfield River Basin, Massachusetts And Vermont, James G. Macbroom, Roy Schiff, Jessica Louisos

Water Reports

This geomorphic assessment of Deerfield River in western Massachusetts and southern Vermont has been prepared by Milone & MacBroom, Inc. (MMI) on behalf of the University of Massachusetts as part of its "Farms, Floods, and FGM" project, funded by the United States Department of Agriculture – National Institute of Food and Agriculture National Integrated Water Quality Program(USDA – NIFA NIWQP) program. This project is a broad-based geomorphic assessment of the Deerfield River and its adjacent riparian corridor to define its characteristics, processes, and management issues. The river channel is used extensively for hydroelectric power generation and recreation, with agricultural …

Environmental Implications Of Nanotechnology, Boris Lau, Joann Mariie Rodríguez

Science and Engineering Saturday Seminars

No abstract provided.

Wood Studio Workshop, Peggi Clouston, Rommel L Cordova‐Fiori

Science and Engineering Saturday Seminars

No abstract provided.