Engineering Commons^™

Benchmarking Of A Sco2 Heat Exchanger Flow Loop, David Velasco

Doctoral Dissertations and Master's Theses

Heat transfer of supercritical carbon dioxide (sCO2) was studied experimentally by commissioning a sCO2 flow loop featuring a horizontal tube-in-tube counterflow heat exchanger with a circular cross section. The main objective was to establish experimental heat transfer research capabilities for sCO2 at Embry-Riddle Aeronautical University’s (ERAU) Thermal Science Lab. sCO2 experiences a drastic change in thermophysical properties near its critical point that results in unique heat transfer characteristics. The high pressures at which sCO2 exists make the large gradients in thermophysical and transport properties difficult to study, experimentally and numerically. However, understanding the heat transfer characteristics and thermophysical behavior of …

Assessing The Thermodynamic Potential Of Deep Eutectic Solvents In The Absorption Of Greenhouse Gases Through Computational Methods., Thomas Michael Quaid

Theses and Dissertations

Greenhouse gas (GHG) capture is a fundamental technology in the fight against climate change. Some species of devastating GHGs like fluorinated compounds are released directly to the air from industrial processes. Some GHGs are co-produced in sustainably derived biofuels which require absorptive upgrading. The development of more efficient, cost effective, and environmentally friendly methods of capturing GHG’s from pollutant sources and industrial streams is of utmost importance in the fight against climate change. Deep eutectic solvents have entered the separations stage as potential disruptors to conventional solvent choices for a variety of applications. Deep eutectic solvents (DES) are compounds of …

The Design Estimate Of A Warehouse Refrigeration System, Jackson Dear

Honors Theses

The intention of this project was to provide a design and cost estimate for the refrigeration systems within an industrial cold storage distribution center for Magnolia Country Frozen Foods, Inc. in East Rutherford, NJ. The facility includes eighteen 300,000 ft3 units (200 ft x 100 ft x 15 ft). These units require 200 tons of refrigeration at a maintained temperature of 0oF. This project's scope included choosing an optimal refrigeration system, selecting a refrigerant for use within the system, and providing a cost estimate for the purchase of the refrigeration system equipment and for the yearly cost associated with running …

Anion Alloying Of Iii-V Semiconductors For Water Splitting., Sonia Calero-Barney

Electronic Theses and Dissertations

The challenge of solar energy conversion and storage translates into the discovery and development of semiconductor materials that can transform sunlight energy into electricity and/or high-energy-density fuels in a cost-effective way. From the solar energy conversion perspective, cation-alloyed III-V solar cells hold record-breaking energy conversion efficiencies, while anion-alloyed III-V’s are particularly interesting for photoelectrochemical hydrogen generation. The major challenge for the adoption of III-V-based technologies lies in the high manufacturing costs of established synthesis techniques and the difficulty to control the composition of ternary alloys. One of the materials investigated in this work is GaSb_zP_1-z. Thermodynamic …

The Design And Economic Optimization Of A Warehouse Refrigeration System, Hannah Talbot

Honors Theses

The purpose of this project was to design a cool warehouse refrigeration system for Acme Frozen Foods, Inc located in Newark, New Jersey. The refrigeration system was used to cool eighteen 300,000 ft³ refrigerated units (200 ft x 100 ft x 15 ft), each requiring 200 cooling tons of refrigeration at a level of 0 F. The scope of this project included determining the appropriate refrigeration cycle, selecting the most desirable refrigerant, and temperature ranges to optimize the performance of the system. This project also considered the economic cost of the power needed to run the refrigerated units and …

Thermodynamic Vapor-Liquid Equilibrium In Naphtha-Water Mixtures, Sandra Milena Lopez-Zamora

Electronic Thesis and Dissertation Repository

Naphtha is used to dilute the froth from bitumen treatment. Naphtha is recovered using a Naphtha Recovery Unit (NRU) and sent back to the froth dilution step. To minimize the environmental and economic impact of the NRU, it is imperative to maximize the naphtha recovery. It is, in this respect, that enhanced NRU Vapour-Liquid-Liquid equilibrium data is a significant value. The prediction of phase equilibria for hydrocarbon/water blends in separators, is a subject of considerable importance for chemical processes. Despite its relevance, there are still pending questions. Among them, is the prediction of the correct number of phases. While a …

Relationship Between Thermal Conductivity And Free Electrons In Metal, Yansong Liu

Senior Theses

An experiment was designed and conducted to explore the relationship between thermal conductivity with free electrons in metal. In the experiment, copper, iron, aluminum, and titanium rods with close diameters were used to carry out the experiment. Each rod was heated up by a heat unit at one end while cooled on the other end with a heat sink to maintain a steady state. DC current was applied to rods in the direction along, as well as against, the heat flow. Thermal conductivities were measured in these two situations for each rod. Results showed electrons do dominate thermal flow inside …

Theoretical Investigations Of The Electronic, Magnetic, And Thermoelectric Properties Of Transition-Metal Based Compounds, Haleoot Edaan Raad

Graduate Theses and Dissertations

The electronic, magnetic, and thermoelectric properties of transition-metal based compounds were investigated by using the density functional theory and Boltzmann transport formalism. It was found that the Co-based Heusler compounds and InSe monochalcogenide are among the materials that may be used for future thermoelectric devices. Furthermore, the investigation showed that the quaternary Heusler compounds, such as, CoFeYGe, where Y is Ti or Cr, are half-metallic ferromagnetic materials with full electron spin polarization. The lattice thermal conductivity (κL) was found to decrease for these alloys as the temperature increases. The present investigation indicated that the phonon optical modes have a major …

Quantifying And Elucidating The Effect Of Co2 On The Thermodynamics, Kinetics And Charge Transport Of Aemfcs, Yiwei Zheng

Theses and Dissertations

Anion exchange membrane fuel cells (AEMFCs) have shown significant promise to provide clean, sustainable energy for grid and transportation applications – and at a lower theoretical cost than more established proton exchange membrane fuel cells (PEMFCs). Adding to the excitement around AEMFCs is the extremely high peak power that can now be obtained (> 3 W cm-2) and continuously improving durability (1000+ h), which has made the future deployment of AEMFCs in real-world applications a serious consideration. For some applications (e.g. automotive), the most critical remaining practical issue with AEMFCs is understanding and mitigating the effects of atmospheric CO2 (in …

Sorption Of Benzene, Tolueneand Ethylbenzeneby Plasticized Pema And Pema/Pmma Sensing Films Using Aquartz Crystal Microbalance (Qcm) At 298.15k, Deekshitha Adapa

USF Tampa Graduate Theses and Dissertations

Detection of volatile organic compounds (VOC’s) in the environment is important for human health and wellness. Long term exposure of certain VOC’s like benzene, toluene, ethylbenzene and xylene (BTEX) has a severe effect on human health. There are techniques such as gas chromatography, photo ionization, and mass spectroscopy that are time consuming, require gas sampling and are ineffective in real time sensing in air. Acoustic wave devices such as surface acoustic wave (SAW) devices can be used for sensing BTEX compounds in both vapor and liquid phase. The quartz crystal microbalance (QCM) is a low-frequency acoustic wave device, which can …

Decoding Complexity In Metabolic Networks Using Integrated Mechanistic And Machine Learning Approaches, Tolutola Timothy Oyetunde

McKelvey School of Engineering Theses & Dissertations

How can we get living cells to do what we want? What do they actually ‘want’? What ‘rules’ do they observe? How can we better understand and manipulate them? Answers to fundamental research questions like these are critical to overcoming bottlenecks in metabolic engineering and optimizing heterologous pathways for synthetic biology applications. Unfortunately, biological systems are too complex to be completely described by physicochemical modeling alone.

In this research, I developed and applied integrated mechanistic and data-driven frameworks to help uncover the mysteries of cellular regulation and control. These tools provide a computational framework for seeking answers to pertinent biological …

Multicomponent Working Fluids In Organic Rankine Cycle Evaporators, Jennifer Fromm

Honors Theses

Organic Rankine cycles are a promising technology to convert waste heat energy into usable mechanical or electric power, giving them the potential to reduce fossil fuel emissions generated by traditional energy generation. The heat exchangers of these devices are of particular interest, as maximizing energy extraction from these free heat sources will increase net electrical power output. For this project I created a model to predict the effects of mixture working fluids on the evaporator performance of an organic Rankine cycle generator for a wide range of waste heat source temperatures. This model combines empirically derived heat exchanger performance parameters …

Modeling Of Nanoscale Transport In Mesoporous Membranes, Ashutosh Rathi

Doctoral Dissertations

Mesoporous membranes with pore sizes in the range 2-50 nm provide an energy efficient alternative for separation of mixtures such as CO₂ from stack effluents and volatile organic compounds (VOC) from air. Transport mechanisms such as capillary condensation, Knudsen diffusion and surface adsorption help in enrichment of a more condensable component based on the bulk mixture thermodynamics, surface chemistry and geometry of the mesopores. Despite the progress in synthesis techniques, design of better mesoporous materials for targeted separations is still a challenge due to the absence of clear design rules. Modeling techniques can be used to quantify the relevant …

Technical Feasibility Of Selectively Separating Rare Earth Elements By Vapor Phase Extraction And Condensation, Katie Lyons

Graduate Theses & Non-Theses

Experiments were performed to evaluate the technical feasibility of selectively separating selected rare earth halides (bromides and chlorides) using a volatilization and condensation technique. Initially, optimum chloridizing and bromidizing roast parameters were secured in studies performed on reagent grade rare earth oxide samples and subsequently confirmed in tests performed on mineral ore and concentrate samples. The volatilization and condensation experiments were performed by placing the subject rare earth halide samples in an argon-purged multiple-zone tube furnace wherein the temperature profile was controlled to establish separate vaporization and condensation regions. Following each experiment, condensate and solid residue samples were analyzed to …

Study Of The Self-Assembly Process Of Microporous Materials Using Molecular Modeling, Mohammad Navaid Khan

Doctoral Dissertations

Zeolites are an important class of materials in modern technology with applications in catalysis, separations, biosensing and microelectronics. There are over 200 different zeolite frameworks reported in literature, but only a handful have been used commercially. Understanding their self-assembly process would assist in the fabrication of new zeolites through the control of their pore size/shape, and surface area for advanced applications. With our research we aim to elucidate aspects of zeolite formation using molecular simulations. We have extended the lattice model of silica tetrahedra developed by Jin et al. [L. Jin, S. M. Auerbach and P. A. Monson J. Chem. …

Prediction Of Vapor/Liquid Equilibrium Behavior From Quantum Mechanical Data, Marshall J. Gnap

Williams Honors College, Honors Research Projects

MOSCED (Modified Separation of Cohesive Energy Density) is a particularly attractive model for activity coefficients because it offers intuitive insights into how to tune solvent-solute interactions to achieve optimized formulations. Unfortunately, only 133 compounds have been characterized with the MOSCED method. Furthermore, there is no convenient method for extending MOSCED predictions to new compounds. The hypothesis of the present research is that the surface charge density of a molecule, once normalized over the molecule surface area, provided graphically by a σ-profile from density functional theory (DFT) computations, can be used to estimate the parameters used in the MOSCED model. DFT …

Measurements And Modeling Of Hydrocarbon Mixture Fluid Properties Under Extreme Temperature And Pressure Conditions, Babatunde A. Bamgbade

Theses and Dissertations

Knowledge of thermodynamic fluid properties, such as density and phase behavior, is important for the design, operation, and safety of several processes including drilling, extraction, transportation, and separation that are required in the petroleum. The knowledge is even more critical at extreme temperature and pressure conditions as the search for more crude oil reserves lead to harsher conditions. Currently, there is dearth of experimental data at these conditions and as such, the predictive capability of the existing modeling tools are unproven. The objective of this research is to develop a fundamental understanding of the impact of molecular architecture on fluid …

Thermodynamic Modeling Of Uranium And Oxygen Containing Ternary Systems With Gadolinium, Lanthanum, And Thorium, Jacob Wesley Mcmurray

Doctoral Dissertations

The CALPHAD method is used to assess the thermodynamic properties and phase relations in the U-M-O system where M = Gd, La, and Th. A compound energy formalism (CEF) model for fluorite UO_2±x [urania] is extended to represent the complex U_1-yM_yO_2±x [urania solid solution] phases. The lattice stabilities for fictive GdO₂ [gadolinia] and LaO₂ [lanthana] fluorite structure compounds are calculated from density functional theory (DFT) for use in the CEF for U_1-yM_yO_2±x [urania solid solution phase] while U⁶⁺ [uranium 6 plus cation] is introduced into the …

Enhancement Of Mass Transfer And Electron Usage For Syngas Fermentation, James J. Orgill

Theses and Dissertations

Biofuel production via fermentation is produced primarily by fermentation of simple sugars. Besides the sugar fermentation route, there exists a promising alternative process that uses syngas (CO, H2, CO2) produced from biomass as building blocks for biofuels. Although syngas fermentation has many benefits, there are several challenges that still need to be addressed in order for syngas fermentation to become a viable process for producing biofuels on a large scale. One challenge is mass transfer limitations due to low solubilities of syngas species. The hollow fiber reactor (HFR) is one type of reactor that has the potential for achieving high …

Mixed Surfactant Systems: Thermodynamics And Applications In Metal Oxide Imprinting, Suvid Joshi

Theses and Dissertations--Chemical and Materials Engineering

In this work we study mixtures of cationic surfactant (CTAB) and sugar based surfactant(s) (octyl beta-D-glucopyranoside (C8G1), dodecyl maltoside (C12G2) and octyl beta-D-xylopyranoside (C8X1)) to understand the non-ideal thermodynamic behavior of the mixtures of cationic and non-ionic surfactants in water and synthesis of imprinted materials. The thermodynamics of micellization, mixing and dilution of these systems are studied using Isothermal Titration Calorimetry (ITC) and the experimental data obtained are modeled with a pseudo-phase separation model with non-ideal mixing described by regular solution theory. It is shown that a model accounting for enthalpy of demicellization and enthalpy of dilution based on McMillan-Mayer …

Protein-Surface Interactions With Coarse-Grain Simulation Methods, Shuai Wei

Theses and Dissertations

The interaction of proteins with surfaces is a major process involved in protein microarrays. Understanding protein-surface interactions is key to improving the performance of protein microarrays, but current understanding of the behavior of proteins on surfaces is lacking. Prevailing theories on the subject, which suggest that proteins should be stabilized when tethered to surfaces, do not explain the experimentally observed fact that proteins are often denatured on surfaces. This document outlines several studies done to develop a model which is capable of predicting the stabilization and destabilization of proteins tethered to surfaces. As the start point of the research, part …

Thermodynamic, Sulfide, Redox Potential, And Ph Effects On Syngas Fermentation, Peng Hu

Theses and Dissertations

Recently, work in ethanol production is exploring the fermentation of syngas (primarily CO, CO2, and H2) following gasification of cellulosic biomass. The syngas fermentation by clostridium microbes utilizes the Wood-Ljungdahl metabolic pathway. Along this pathway, the intermediate Acetyl-CoA typically diverges to produce ethanol, acetic acid, and/or cell mass. To develop strategies for process optimization, a thermodynamic analysis was conducted that provided a detailed understanding of the favorability of the reactions along the metabolic pathway. Thermodynamic analysis provided identification of potentially limiting steps. Once these limiting reactions were identified, further thermodynamic analysis provided additional insights into the ways in which reaction …

The Structure And Stability Of Alpha-Helical, Orthogonal-Bundle Proteins On Surfaces, Shuai Wei

Theses and Dissertations

The interaction of proteins with surfaces is a major problem involved in protein microarrays. Understanding protein/surface interactions is key to improving the performance of protein microarrays, but current understanding of the behavior of proteins on surfaces is lacking. Prevailing theories on the subject, which suggest that proteins should be stabilized when tethered to surfaces, do not explain the experimentally observed fact that proteins are often denatured on surfaces. In an attempt to develop some predictive capabilities with respect to protein/surface interactions, it was asked in previous works if the stabilization/destabilization of proteins on surfaces could be correlated to secondary structure …

Demonstration Of A Strategy To Perform Two-Dimensional Diode Laser Tomography, Ryan N. Givens

Theses and Dissertations

Demonstration of a strategy to perform two-dimensional diode laser tomography using a priori knowledge from symmetry arguments and computational fluid dynamic (CFD) calculations is presented for a flat flame burner. The strategy uses an optimization technique to determine flame diameter and location using a vector quantization approach. Next, the variance in a training set, produced from CFD calculations, is captured using principal components analysis. The information in the training set allows interpolation between beam paths resulting in temperature and density maps. Finally, the TDLAS temperature and density maps are shown to agree with traditional thermocouple measurements of the flat flame …

Cycle Performance Of A Pulse Detonation Engine With Supercritical Fuel Injection, Timothy M. Helfrich

Theses and Dissertations

Pulse detonation engines (PDE) rely on rapid ignition and formation of detonation waves. Because hydrocarbon fuels are composed typically of long carbon chains that must be reduced in the combustion process, it would be beneficial to create such reduction prior to injection of fuel into the engine. This study focused on PDE operation enhancements using dual detonation tube, concentric-counter-flow heat exchangers to elevate the fuel temperature up to supercritical temperatures. Variation of several operating parameters included fuel type (JP-8, JP-7, JP-10, RP-1, JP-900, and S-8), ignition delay, frequency, internal spiral length, and purge fraction. To quantify the performance, four key …

Thermodynamic Property Prediction For Solid Organic Compounds Based On Molecular Structure, Benjamin T. Goodman

Theses and Dissertations

A knowledge of thermophysical properties is necessary for the design of all process units. Reliable property prediction methods are essential because reliable experimental data are often not available due to concerns about measurement difficulty, cost, scarcity, safety, or environment. In particular, there is a lack of prediction methods for solid properties. Predicted property values can also be used to fill holes in property databases to understand more fully compound characteristics. This work is a comprehensive analysis of the prediction methods available for five commonly needed solid properties. Where satisfactory methods are available, recommendations are made; where methods are unsatisfactory in …

Thermodynamic And Leaching Studies Of Various Systems, Satya D. Rami

Theses

The group contribution approach is a reliable and fast method for the prediction of liquid phase activity coefficients in none lectrolyte, nonpolymeric mixtures at low to moderate pressures and temperatures between 300 and 425 K. It has become widely used in practical chemical engineering applications in cases where little or no relevant experimental information is available.

The two group contribution methods examined in the course of this work, are the Knox and & UNIFAC models. Group interaction parameters are evaluated for each of these models and results compared. Although the results for both models are similar when sufficient data are …

The Thermodynamics Of Electrolytic Solutions, Eric Robert Bixon

Theses

The thermodynamic properties of solutions of electrolytes may be accurately determined by the measurement of the activity of the s6lvent. when the. solute is nonvolatile, this quantity may be obtained from measurements of the lowering of the vapor pressure caused by the presence of the dissolved solute.

An experimental method has been devised to measure this effect using a semi-conventional Othmer Still. The experimental apparatus has been constructed. and evaluated. Data has been-obtained for the vapor pressure lowering of methanol due to the presence of dissolved electrolyte for five different electrolyte-methanol systems. An extrapolation technique was developed to make use …