Engineering Commons^™

Understanding The Weather- And Soil-Related Variability In Agricultural Water Footprints: Case Study Of Maize And Soybeans Grown In The St. Joseph Watershed, Karleigh M. Krieg

Dissertations, Master's Theses and Master's Reports

Introduced in 2002, the water footprint is a valuable tool for understanding the consumption of freshwater resources. The traditional approach to quantifying the water footprint is to sum the green, blue, and gray water footprint components. The green water footprint is the volume of water that comes from precipitation, is stored in the soil, and used by vegetation. The blue water footprint is the volume of surface or ground water that is withdrawn and applied to cultivated lands via irrigation. These components are based on the evapotranspiration of green and blue water resources, respectively. The gray water footprint is the …

Role Of Eta Phase Evolution On Creep Properties Of Nickel Base Superalloys Used In Advanced Electric Power Generation Plants, Ninad Mohale

Dissertations, Master's Theses and Master's Reports

Advanced fossil energy power generation plants require materials that withstand high temperatures and corrosive environments. One such material that is used in steam turbines is Nimonic 263. It is a nickel-base superalloy that is principally strengthened by gamma primephase (Ni₃(Ti, Al)) and has an L1₂structure. At extended times and at turbine operating temperatures however, eta (Ni₃Ti) phase is known to form at the expense of gamma prime. Eta has a complex DO₂₄structure and is the stable phase between 750°C and 900°C, but with slow kinetics of formation. Little is understood about eta …

Modeling The Effects Of Wastewater Infrastructure Options On Water Quality In Greater Cleveland, Ohio, Mike Foster

Dissertations, Master's Theses and Master's Reports

The city of Cleveland, OH, and the Northeast Ohio Regional Sewer District are in the process of an ambitious engineering project designed to reduce the amount of untreated wastewater that is discharged into Lake Erie and its tributaries. The project involves the construction of seven tunnels that will intercept combined sewer overflows for transport to wastewater treatment plants, along with upgrades to the treatment capacity of these plants. This report will examine the water quality impacts of this project, as well as the impact of six additional proposed management options, on the streams of Greater Cleveland and the Lake Erie …

Metalimnetic Oxygen Minimum In Green Lake, Wisconsin, Mahta Naziri Saeed

Dissertations, Master's Theses and Master's Reports

Green Lake, located in Green Lake County, Wisconsin, has been experiencing summer Metalimnetic Oxygen Minima (MOM). The severity of the MOM has increased in recent years and the lake was listed as impaired in 2014. To investigate the MOM, the lake was monitored during 2017 and 2018 at two sites using moored temperature and oxygen sensors recording at 1-hour intervals. Using these data, a hydrodynamic model (Simstrat) was configured for the lake. A new model was then developed to simulate the oxygen changes in the lake. Productivity, respiration, sediment oxygen demand (SOD) and fluxes were included, and hydrodynamics were driven …

The Role Of Ephemeral Stratification, Anoxia, And Entrainment In Mediating Spatiotemporal Trophic State Dynamics In A Lake Michigan Drowned River Mouth System (Mona Lake, Mi), Hayden Henderson

Dissertations, Master's Theses and Master's Reports

Mona Lake, MI (a drowned river mouth system) has become eutrophic as result of cultural eutrophication. The integrated monitoring effort and subsequent modeling (LAKE2K) reported on here has shifted the management focus to internal phosphorus loads (60 percent of annual load, 90 percent of load during the stratified and anoxic period) as a necessary precursor to trophic state change. Sediment phosphorus release can yield extreme elevations (> 1 mgSRP/L) of bottom water soluble reactive phosphorus (SRP), with blooms of potentially toxic cyanobacteria (largely Microcystis) occurring annually. Such blooms are ascribable to stochastic mixing and phosphorus entrainment to the surface waters, …

Development Of A 2d Scr Catalyst On A Diesel Particulate Filter Model For Design And Control Applications To A Ultra Low Nox Aftertreatment System, Venkata Chundru

Dissertations, Master's Theses and Master's Reports

This research focuses on modeling and control of PM and NO_x in diesel engine exhaust using an SCR catalyst on a Diesel Particulate Filter (SCR-F). A 2D SCR-F model was developed that is capable of predicting internal states: 2D temperature, PM and NH₃storage distributions and filtration efficiency, pressure drop, PM mass retained in the PM cake and substrate wall and outlet NO, NO₂and NH₃concentrations. The SCR-F model was used to simulate a DOC + SCR-F + DOC + SCR ultra-low NOx system that can achieve > 99.5% NOx conversion efficiency.

The model was calibrated …

Physical Modeling Of Lithium-Ion Aging For Automotive Applications, Anurag Kamal

Dissertations, Master's Theses and Master's Reports

This thesis extends the full-scale electrochemical model for a Lithium-ion battery based on the porous electrode theory to incorporate aging mechanisms of solid electrolyte interface formation, cyclic electrode degradation, and lithium plating during overcharge, automotive vibrations, mechanical stress, and cell temperature, as reported in the existing literature. Further, the thesis presents the scope of the parameters used in the model to enable designers to extend the equations for new mechanisms and variability of other parameters.

An increased set of equations makes the complexity of the model even higher, and it would be very computationally complex to simulate this model. This …

An Experimental Investigation Of The Effect Of Temperature And Space Velocity On The Performance Of A Cu-Zeolite Flow-Through Scr And A Scr Catalyst On A Dpf With And Without Pm Loading, Vaibhav Kadam

Dissertations, Master's Theses and Master's Reports

Abstract The heavy-duty diesel (HDD) engines use the diesel oxidation catalyst (DOC), catalyzed particulate filter (CPF) and urea injection based selective catalytic reduction (SCR) systems in sequential combination, to meet the US EPA 2010 PM and NOₓ emission standards. The SCR along with a NH₃ slip control catalyst (AMOX) offer NOₓ reduction >90 % with NH₃ slipHowever, there is a strong desire to further improve the NOₓ reduction performance of such systems, to meet the California Optional Low NOₓ Standard implemented since 2015. Integrating SCR functionality into a diesel particulate filter (DPF), by coating the SCR catalyst on the DPF, …

Modeling, Simulation And Control Of Hybrid Electric Vehicle Drive While Minimizing Energy Input Requirements Using Optimized Gear Ratios, Sanjai Massey

Dissertations, Master's Theses and Master's Reports

This project was conducted to analyze (model and simulate) and optimize an electric motor based drive system to propel a typical passenger vehicle in an urban driving environment. Although there are many HEV and EV type systems on the market today, this paper chose the Toyota Prius HEV system as a baseline using a brushless AC motor.

Although a vehicle can be driven many ways, a more standardized Urban Dynamometer Driving Schedule, UDDS, was chosen to simulate real driving conditions. This schedule is determined by the US Environmental Protection Agency, EPA, and is intended to represent the city driving conditions …

Mechanistic Models On Enzymatic Hydrolysis And Anaerobic Digestion, Yang Zhang

Dissertations, Master's Theses and Master's Reports

For enzymatic hydrolysis, a mechanistic model on enzymatic hydrolysis of pure cellulosic substrates was improved to consider oligomer reactions with beta-glucanases, inhibition of oligomers to cellulases and enzyme decay. Then a novel and general modeling framework was developed for enzymatic hydrolysis of hemicellulose-cellulosic substrates. This mechanistic model, for the first time, took into consideration explicitly the time evolution of morphologies of intertwining cellulose and hemicelluloses. This novel mechanistic model was applied to optimize the composition of enzyme mixtures for substrate conversion and monosaccharides yield during simultaneous enzymatic hydrolysis of different lignocellulosic substrates. For anaerobic digestion, the original "Anaerobic Digestion Model …