Search Results (1 - 8 of 8 Results)

Sort By  
Sort Dir
 
Results per page  

Crawford, Daniel PMinimizing Pollution Through Semi-Antagonistic Equilibrium Points
Master of Science, University of Akron, 2013, Mathematics
A game theoretic model between a firm and regulator is studied in an effort to minimize pollution. This paper focuses on locating semi-antagonistic equilibrium points within the model for the purpose of verifying a suggestion that such points might identify equilibrium strategies that also minimize pollution amongst all equilibrium points. The impact of the variables governing the model on the existence of these sorts of points is also covered. A program will produce scatter plots that show the existence of such points under different conditions, revealing the inability of this type of point to guarantee the desired outcome.

Committee:

Stefan Forcey, Dr. (Advisor); James Cossey, Dr. (Committee Member); Gerald Young, Dr. (Committee Member)

Subjects:

Economic Theory; Mathematics

Keywords:

game theory; pollution; equilibria; equilibrium points

Sans, Amanda DzintraTRANSFERABLE STEP-POTENTIALS FOR HALOGENATED HYDROCARBONS AND MIXTURE PREDICTIONS FROM SPEADMD
Master of Science, University of Akron, 2006, Chemical Engineering
Molecular simulation is a powerful tool used to find thermodynamic properties of fluids. In this research, the molecular simulation program called Step-Potentials for Equilibria and Molecular Dynamics, SPEADMD, was advanced by developing the potentials for halogenated hydrocarbons and by examining mixtures. Previous to this work, mixture behavior could not be extensively examined because of the absence of halogenated hydrocarbons. The step-potentials for halogenated hydrocarbons were found by regressing the simulation results to match experimental data for vapor pressure and liquid density resulting in roughly 3% absolute average deviation in vapor pressure for most compounds. The potential for the perfluorinated hydrocarbons showed a unique softness that could not be explained by the traditional step-potential, thus a “soft-shoulder” potential was needed to explain the slope of the vapor pressure curve and coincidentally explain the mixture behavior of perfluoroalkanes + alkanes. The mixing rules developed for SPEADMD were tested using a standard vapor-liquid equilibrium database, which includes a variety of non-ideal and ideal mixtures. A new approach called the SPEADMDã method was implemented in order to separate the SPEADMD vapor pressure error from the mixture bubble pressure error. The SPEADMDã was competitive with other mixture models while SPEADMD was not because of the high vapor pressure error from simulation results.

Committee:

Jarrell Elliott (Advisor)

Subjects:

Engineering, Chemical

Keywords:

Molecular simulation; SPEADMD; vapor pressure; vapor-liquid equilibria; perfluoroalkanes; halogenated hydrocarbons

Chun, Joong-HyunNMR Studies of the Hydration Equilibria of Mesylate and Dialkyl Phosphate Derivatives of Acetone; and Investigations of Novel Hypervalent Iodine Compounds
Doctor of Philosophy, University of Akron, 2005, Chemistry

The aryl-λ3-iodane, [hydroxy((bis(2,2,2-trifluoroethoxy)phosphoryl)oxy)iodo]benzene (1), was prepared from [hydroxy(tosyloxy)iodo]benzene and sodium bis(trifluoroethyl) phosphate in methanol. This novel iodine (III)-phosphate reagent was employed for the conversion of acetone to its α-bis(trifluoroethyl) phosphate derivative, and for ligand-transfer oxidations of various alkyl iodides to the corresponding alkyl bis(trifluoroethyl) phosphates.

The use of 1 for oxidative rearrangements of arylalkenes to geminal-bisphosphate esters was also explored. Samples of 1 and the known diphenyl analogue, [hydroxy((bis(phenyloxy)phosphoryl)oxy)iodo]benzene were submitted for single crystal X-ray analysis.

Equilibrium constants (KD) for the hydration of α-(mesyloxy)acetone, α-((bis(methoxy)phosphoryl)oxy)acetone, and α-((bis(ethoxy)phosphoryl)oxy)acetone in D2O at 25, 35, 45, and 55 °C were determined by 1H NMR analysis. Plots of log KD versus T-1 enabled calculations of the enthalpy (H) and entropy (S) of hydration for all three substrates. Hydration constants of the ketol phosphates in D2O (KD) and H2O (KH) at 25 °C were also determined by 31P NMR analysis. The hydration constants were employed with reported linear free energy relationships for estimates of Taft polar substituent constants (σ*) of the (mesyloxy)methyl and bis((alkoxy)phosphoryl)oxy)-methyl groups, and equilibrium constants for hydroxide addition to the ketol phosphates. Hydration of the α-bis(trifluoroethyl) phosphate derivative of acetone in D2O was accompanied by spontaneous hydrolysis of the ketol phosphate to two sets of products. The mechanistic origin of the phosphate products was examined by conducting the hydrolysis in D2O mixed with 18O-labeled H2O.

4,4-Dimethyl-2-nitromethyl-2-(diacetoxyiodo)biphenyl was synthesized from 4,4-dimethyl-2-iodobiphenyl and submitted for single crystal X-ray analysis. A key step in the synthetic procedure was ring-opening of a cyclic iodonium salt with nitromethane anion. A preliminary 1H NMR study of the dynamic behavior of the biaryl-3-iodane was conducted and its cyclization with p-toluenesulfonic acid to a dibenziodonium salt was demonstrated. Efforts to convert the diacetoxyiodane and the corresponding iodo compound to an iodine (III) heterocycle containing the 9-iodaphenanthrene ring system were unsuccessful.

Committee:

Gerald Koser (Advisor)

Subjects:

Chemistry, Organic

Keywords:

HYDRATION EQUILIBRIA; HYPERVALENT IODINE COMPOUNDS

Zhang, WeiStudy of Central Configurations and Relative Equilibria in the Problem of Four Bodies
MS, University of Cincinnati, 2000, Engineering : Computer Science
Central configurations and relative equilibria problems in N-body system have been studied for more than two hundred years. Due to its complexity, so far there is no complete theoretical solution when N>3. In this study, we reviewed the bifurcation study in four body system. With the help of Mathematica software package, we studied the general potential equation under the condition that the moment of inertia remains constant. By further applying symmetrical constraint and center of mass constraint, we were able to study the bifurcation appeared in four body system graphically and have a better understand about its mechanism. Meanwhile, we developed software package Minalysis with Microsoft MFC. Minalysis provides a graphical user interface (GUI) so that the user can easily perform a search for central configurations and obtain numerical results. In Minalysis, we implemented downhill simplex minimization algorithm in searching for planar central configurations. The study shows that the results of Mathematica study and numerical study match well and downhill simplex minimization algorithm is effective in central configuration and relative equilibria study, especially with the combination of GUI technique.

Committee:

Dieter Schmidt (Advisor)

Subjects:

Computer Science

Keywords:

Central configuration; relative equilibria; bifurcation; numerical analysis; downhill simplex algorithm; minimization

Solomon, Raphael Haim ReuvenEvery bank run need not cause a currency crisis. models of twin crisis with imperfect information
Doctor of Philosophy, The Ohio State University, 2003, Economics
In the 1970's, the “twin crisis” pattern emerged: currency crises often followed bank runs. Many observers developed deterministic twin crisis models: every bank run causes a currency crisis. These models contrast with the historical record: even if several banks fail, the currency peg may survive. A satisfactory theory of such phenomena allows for endogenous twin crises. This dissertation consists of two endogenous twin crisis models and an empirical examination of these models. The first chapter, Anatomy of a Twin Crisis, models twin crisis in a one-bank setting with risk-averse domestic depositors and risk-neutral foreign depositors. Some domestic depositors (“impatient”) require immediate liquidity. Other depositors demand immediate liquidity when fearing bank failure. Depositors use imperfectly correlated sunspot variables when deciding to run. Domestic depositors observe one sunspot variable; foreigners observe another. A net foreign reserve drain may cause a currency crisis. Foreign depositors contribute to this drain through currency conversions; domestic depositors exacerbate the drain by running, forcing a bank bailout. When foreign and domestic depositors run on the bank, currency crisis results; a run by foreign or domestic depositors alone need not provoke a crisis. The second chapter, When Bad Things Happen to Good Banks, emphasizes systemic aspects of twin crises. This model features multiple ex-ante identical banks and depositors who observe sunspots specific to their bank and country of residence. After calibrating to Turkish data, the model computes “systemic risk” - the probability that sufficient banks fail, causing a currency crisis. Systemic risk may be fundamental or self-fulfilling. As the fraction of impatient depositors increases, the banks' emphasis shifts from serving depositors to providing consumption insurance. Also, almost all systemic risk is self-fulfilling. The model predicts that increasing interbank deposits encourages banks to consider systemic impacts of their actions. The third chapter, Diamond-Dybvig Theory Passes a Simple Test, examines withdrawal decisions by domestic and foreign investors in detail. When depositors “run,” they choose short-maturity deposits over long-maturity ones. If many depositors run, banks face “liquidity shocks.” This chapter demonstrates a relationship between interest rates offered by banks cognizant of the possibility of runs and the liquidity shocks they face.

Committee:

Nelson Mark (Advisor)

Subjects:

Economics, Finance

Keywords:

Bank runs; Currency crises; Diamond-Dybvig; Liquidity shocks; Multiple equilibria; Sunspots

Qian, ZexinThe Impact of Humidity on an Optical Chemical Sensing Device for Non-invasive Exhaled Gas Monitoring
MS, University of Cincinnati, 2016, Engineering and Applied Science: Chemical Engineering
A novel technique for the detection of acetone in human breath was previously developed as a non-invasive medical diagnostic tool for potential use in the monitoring blood glucose level of diabetic patients. Perfluorosulfonic acid (PSA) polymer membrane, commercially available as Nafion® 117, was used as the heterogeneous catalyst for the condensation reaction of ambient acetone and imbibed immobilized resorcinol reagent. The condensation reaction product, a flavan compound, yielded a unique colorimetric response, which can be measured over time using UV/VIS spectroscopy. Previous studies have shown that by introducing a weak organic acid such as tiglic acid into the membrane prior to exposure, it is possible to preserve the catalytic activity of the PSA groups. An increase in light absorbance due to the reaction was observed in the presence of 100% relative humidity as the concentration of the tiglic acid imbibed increased. This was the first time this colorimetric response was shown to provide comparable light absorption under both ambient humidity and 100% relative humidity condition. The focus of the research described this thesis was to develop an optical sensing device for real time detection in practical clinical applications. An in-situ flow cell was used in this work to determine whether the condensation reaction was able to provide a rapid response during acetone exposure. Using the flow cell system, dynamic response of different concentration of tiglic acid imbibed membrane exposure to both ambient humidity and 100% relative humidity was determined. The dynamic response obtained in this research confirmed that acid based membrane was able to provide us a signal within 100 seconds under both dry and wet condition. The results suggested that the acid based membrane can be used in uncontrollable humidity environment such as human breath but only in the kinetic-controlled region of acetone transport into the membrane. As part of this work, evaluation and optimization of a bench-top prototype was conducted to evaluate the effects of temperature, flow rate and pre and post humidification of both membrane and sample chamber. A strong linear correlation of the optical signal from the device was observed at a given exposure to acetone at early times as long as steady humidification in the sample chamber was maintained. Steady humidification was inferred from the strong influence of flow rate (which affected pressure), temperature, and sample chamber pre-conditioning. A small group of clinical trials were conducted assess the prototype response under real-world conditions. As in the case of constant acetone exposure, linear correlation (typically, R2>0.9) was observed between the optical response and exposure at early times. Consistent with previous work that suggested correlation of breath acetone and blood glucose, we observed a linear correlation between the slope of the optical response and breath acetone concentrations and blood glucose concentrations for diabetics. Such excellent correlations motivate further research on uses of this device to assess the exhaled breath composition for various disease biomarkers.

Committee:

Anastasios Angelopoulos, Ph.D. (Committee Chair); Jonathan Bernstein, M.D. (Committee Member); Rakesh Govind, Ph.D. (Committee Member)

Subjects:

Chemical Engineering

Keywords:

sensor;Nafion;acetone;acid based equilibria

Eastman, Christopher MichaelPhase Equilibria and Interdiffusion in Ni-Cr-Al-Pt Alloy Systems
Master of Science, The Ohio State University, 2011, Materials Science and Engineering
Pt-containing NiAl (more simply referred as Pt aluminide) coatings have been widely used in jet engines either as stand-alone oxidation and hot-corrosion resistant coatings or as bond coats in thermal barrier coating systems for life extension and for increased temperature capabilities of the airfoils. To enable computational design and life prediction of these coatings (especially for simulating coating – substrate interactions), phase diagram and diffusivity information of the Ni-Al-Cr-Pt system (including Ni-Al-Cr, Ni-Al-Pt, Ni-Cr-Pt, and Al-Cr-Pt) are essential. Among these ternaries, only Ni-Al-Cr has been well assessed. The remaining three ternaries were studied in the present research using a Ni-Cr-Pt diffusion multiple together with a series of aluminization treatments and electron probe microanalysis to extract phase equilibria and interdiffusion coefficients. Ternary isotherms have been established for Ni-Cr-Pt at 1200 °C, Ni-Pt-Al at 1150 °C, and Cr-Pt-Al at 1010 °C, which either improve upon and expand on existing isotherms or introduce an entirely new phase diagram (Ni-Cr-Pt). Interdiffusion coefficients were extracted using the Hall, Wagner, and Sauer-Freise methods for Ni-Cr, Ni-Pt, Cr-Pt, Ni-Al, Pt-Al, and Ni-Pt-Al systems. The data presented in this thesis will be used to develop both thermodynamic and mobility databases to be applied to the design, processing development, and life prediction of Pt-containing airfoil coatings.

Committee:

Ji-Cheng Zhao, PhD (Advisor); Yunzhi Wang, PhD (Committee Member)

Subjects:

Engineering; Materials Science; Metallurgy

Keywords:

Ni; Cr; Pt; Al; Interdiffusion; Phase Equilibria; Aluminizing

Kim, Cheol JinLaser float zone growth of superconducting bismuth strontium calcium copper oxide fibers: Characterization and phase equilibria
Doctor of Philosophy, Case Western Reserve University, 1991, Materials Science and Engineering
Superconducting fibers in the Bi-Sr-Ca-Cu-O system have been grown using the laser float zone method. The effect of growth rate and the starting feed rod composition were studied by using XRcase1055778876D, SEM, EDS, TEM, DTA, and optical microscopy. Homogeneous superconducting fibers were obtained from feed rods with the nominal composition of Bi2Sr2CaCu2O8 + δ ("2212") using slow growth rates (≤5 mm/h). The (Sr,Ca)CuO2 solid solution was prevalent when fast growth rates or feed rods with the Bi2Sr2Ca2Cu3O10+δ ("2223") composition were used. Annealing of the as-grown fibers above 800°C for more than 12 hours was effective in reducing the fraction of 1 x 1 phase. T c,mid of the as grown fibers was ∼80K and annealing of these fibers lowered the normal state resistivity. Together with the fiber growth, a phase equilibria study was conducted in an attempt to understand the crystallization behavior of the phases in the LFZ fibers. The phase compatibility relationship in the pseudo-binary Bi2O3-(Sr2CaCu2O x) system at 850°C in air was studied from 0 to 40 cat% Bi. The 2212 phase is compatible with the liquid from compositions of 35-40 cat% Bi at 850°C in air. The seeding of the pre -synthesized 2223 phase to the quenched glass or polycrystalline powders slightly increased propensity to form the superconducting phases

Committee:

Mark DeGuire (Advisor)

Subjects:

Engineering, Materials Science

Keywords:

Laser float zone growth; Superconducting fibers; Phase equilibria