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On The Degradation Of Lubricating Grease, Asghar Rezasoltani
On The Degradation Of Lubricating Grease, Asghar Rezasoltani
LSU Doctoral Dissertations
A comprehensive literature review on physical and chemical degradation monitoring and life estimation models for lubricating greases is presented in chapter one. Degradation mechanisms for lubricating grease are categorized and described, and an extensive survey of the available empirical and analytical grease life estimation models including degradation monitoring standards and methods are presented. In chapter two, irreversible thermodynamic theory is employed to study the mechanical degradation of lubricating grease. A correlation between the mechanical degradation and entropy generation is established and the results are verified experimentally using a rheometer, a journal bearing test rig, and a modified grease worker machine. …
Analysis And Mathematical Modeling Of Autonomously Oscillating Yeast Cultures., Abdelqader M. Zamamiri
Analysis And Mathematical Modeling Of Autonomously Oscillating Yeast Cultures., Abdelqader M. Zamamiri
LSU Historical Dissertations and Theses
The conditions that precede the onset of autonomous oscillations in continuous yeast cultures were studied in three different types of experiments. It was found that the final state of the culture depends on the protocol used to start-up the reactor. Reaching the desired operating point by slow dilution rate changes gave rise to different final states, two oscillatory states and one steady state, depending on the rate of change in dilution rate. The multiplicity of stable states at a single operating point is not explained by current distributed models and points towards a segregated mechanism of these oscillations. The ability …
Design, Fabrication, And Testing Of Cross Flow Micro Heat Exchangers., Chad Randall Harris
Design, Fabrication, And Testing Of Cross Flow Micro Heat Exchangers., Chad Randall Harris
LSU Historical Dissertations and Theses
Cross flow micro heat exchangers were designed to maximize heat transfer from a liquid (water) to a gas (air) for a given frontal area while holding the pressure drop across the heat exchanger of each fluid to values characteristic of conventional scale heat exchangers (car radiators). The cross flow micro heat exchanger design is unique since it produces a very high rate of heat transfer/volume between dissimilar fluids with low fluid pressure drops. Predicted performance for two types of cross flow micro heat exchangers is compared to each other and to current innovative car radiators. Although the cross flow micro …
Development And Evaluation Of A Mass Spectrometer -Based Continuous Emission Monitor For Organic Compound Emissions From Combustion Devices., Emmanuel Tijani Wada
Development And Evaluation Of A Mass Spectrometer -Based Continuous Emission Monitor For Organic Compound Emissions From Combustion Devices., Emmanuel Tijani Wada
LSU Historical Dissertations and Theses
The Mass Spectrometer-based Continuous Emission Monitor (MS-CEM) for organic compounds was developed and evaluated at the Louisiana State University (LSU) Pilot-Scale Rotary Kiln Incinerator (RKI). The MS-CEM consists of stack probe, heat traced sampling line, vacuum pump, particulate filter, Nafion dryer and Extrel mass spectrometer. The Nafion dryer is a special type of dryer that has the ability to remove moisture from the gas sample without removing organic compounds of interest. The mass spectrometer is a quadrupole mass filter. The mass spectrometer includes a computer that controls and optimizes the operation of the unit. The MS-CEM was tested by injecting …
Comparative Efficacy And Quality Characterizatin Of Mayhaw (Crataegus Opaca) Juice Extraction., Alfred Francois Trappey Ii
Comparative Efficacy And Quality Characterizatin Of Mayhaw (Crataegus Opaca) Juice Extraction., Alfred Francois Trappey Ii
LSU Historical Dissertations and Theses
The comparative efficacy and quality characterization of juice by six extraction methods utilizing either frozen or fresh 'Texas Star' mayhaw (Crataegus opaca Hook. and Arn.) fruit obtained from the 1998 and 1999 crop season were conducted according to temperature (cold-press or hot-press extraction) and fruit pulp pretreatment (whole or pulverized fruit with or without pectolytic enzyme). Extraction methods were steam extraction using whole fruit without added pulp juice (SE); steam extraction using whole fruit with added pulp juice (SEP); cold-press extraction using whole fruit (CPE); cold-press extraction using finely macerated fruit pulp (CPEG); hot-press extraction using finely macerated fruit pulp …
Enhanced Sorption Process For The Production Of Hydrogen., Alejandro Lopez Ortiz
Enhanced Sorption Process For The Production Of Hydrogen., Alejandro Lopez Ortiz
LSU Historical Dissertations and Theses
Addition of an inexpensive calcium-based CO2 acceptor (dolomite) to a commercial reforming catalyst resulted in the production of 95+% H 2 from CH4 using sorption-enhanced reaction (SER). The combined reforming, shift, and CO2 separation reactions were sufficiently fast that combined reaction equilibrium was closely approached at 15 atm and 650°C. Process simulations showed that in addition to requiring fewer processing steps, SER permits lower reformer temperature, eliminates the need for shift catalysts, and provides a potential energy savings of 20--25% compared to conventional steam-methane reforming (SMR). An off-gas of pure, sequestration-ready CO2 for greenhouse gas emission control is possible using …
Development Of Pseudostationary Phases For Separations In Electrokinetic Chromatography., Judson Leroy Haynes Iii
Development Of Pseudostationary Phases For Separations In Electrokinetic Chromatography., Judson Leroy Haynes Iii
LSU Historical Dissertations and Theses
The research presented in this dissertation covers pseudo-stationary phase development for separations in electrokinetic chromatography (EKC). Micelles and cyclodextrins have traditionally served as the most popular pseudo-stationary phases (PSPs) used in EKC. However, the development and implementation of PSPs, which have improved properties over traditional ones, are necessary to extend the utility of electrokinetic chromatography. This dissertation covers research contributions, chapter by chapter, to the area of PSP development made by the author. In addition to this, Chapter 1 covers a brief history of chromatography and the fundamentals of capillary electrophoresis and EKC. The first pseudo-stationary phase developed was a …
Plasma Enhanced Chemical Vapor Deposition Of Silicon Nitride And Oxynitride Films Using Disilane As Silicon Source., Giridhar Nallapati
Plasma Enhanced Chemical Vapor Deposition Of Silicon Nitride And Oxynitride Films Using Disilane As Silicon Source., Giridhar Nallapati
LSU Historical Dissertations and Theses
Process characterization details along with the electrical properties of plasma enhanced chemical vapor deposited silicon nitride and oxynitride films are reported, for the first time, using disilane as the silicon source. Two regimes of deposition, namely excess-disilane regime and excess-ammonia regime, were observed for deposition of silicon nitride films using disilane, ammonia and helium. Films deposited under process conditions falling at the boundary of these two regimes had deposition rates that were mostly dependent on rf power and gas flow ratio resulting in highly repeatable film qualities. Silicon nitride films deposited on Si wafers at 250°C and post-metallization annealed in …
Physical And Chemical Properties Of Fibers Extracted From Sugarcane And Kenaf Rind., Simona Cristina Romanoschi
Physical And Chemical Properties Of Fibers Extracted From Sugarcane And Kenaf Rind., Simona Cristina Romanoschi
LSU Historical Dissertations and Theses
Sugar cane fibers were extracted from the rind of cane stalks with sodium hydroxide (NaOH) solutions of different concentrations, at atmospheric pressure, followed by a steam explosion. The extraction process was optimized using a central rotatable composite design, to study the influence of three reaction parameters (alkaline concentration, time of reaction and frequency of tumbling) on fiber bundle properties (weight, length, and tex). Tex was the objective function, with length as a constraint. Regression analysis indicated a quadratic polynomial response. Bleaching studies were conducted on sugar cane fibers extracted with 1.0N NaOH and on kenaf fibers mechanically processed only. Hydrogen …
Feedback Linearizing Control Strategies For Chemical Engineering Applications., Michael James Kurtz
Feedback Linearizing Control Strategies For Chemical Engineering Applications., Michael James Kurtz
LSU Historical Dissertations and Theses
Two widely studied control techniques which compensate for process nonlinearities are feedback linearization (FBL) and nonlinear model predictive control (NMPC). Feedback linearization has a low computational requirement but provides no means to explicitly handle constraints which are important in the chemical process industry. Nonlinear model predictive control provides explicit constraint compensation but only at the expense of high computational requirements. Both techniques suffer from the need for full-state feedback and may have high sensitivities to disturbances. The main work of this dissertation is to eliminate some of the disadvantages associated with FBL techniques. The computation time associated with solving a …
The Production Of Glucooligosaccharides By Leuconostoc Mesenteroides Atcc 13146 And Lipomyces Starkeyi Atcc 74054., Sun Kyun Yoo
The Production Of Glucooligosaccharides By Leuconostoc Mesenteroides Atcc 13146 And Lipomyces Starkeyi Atcc 74054., Sun Kyun Yoo
LSU Historical Dissertations and Theses
Glucooligosaccharides of less than DP 10 were produced either by mixed cultures of Leuconostoc mesenteroides ATCC 13146 and L. starkeyi ATCC 74054, or by an acceptor reaction produced by Leuconostoc mesenteroides ATCC 13146. The yields of glucooligosaccharides produced by mixed culture and acceptor reaction reached up to 49 and 90% of theoretical yield. The composition of carbohydrates at the end of fermentation by mixed culture was 31.4% oligosaccharides, 17.6% dextran, 31.4% mannitol, 2.1% fructose, and 2.4% of sucrose. The composition of carbohydrates at the end of fermentation by acceptor reaction was 32.7% pannose, 30.4% branched isomaltotetraose (DP 4), 21.7% branched …
Characterization Of Aminoalkylcarbamoyl Cellulosic And Chitosan Derivatives For Use In Cosmetic Formulation., Melissa Ann Manuszak Guerrini
Characterization Of Aminoalkylcarbamoyl Cellulosic And Chitosan Derivatives For Use In Cosmetic Formulation., Melissa Ann Manuszak Guerrini
LSU Historical Dissertations and Theses
Polymer and surfactant interactions have been a subject of intense research due to industrial applications utilizing a polymer-surfactant system, such as cosmetic formulation. A series of aminoalkylcarbamoyl cellulose derivatives were prepared from the amidation of methylcarboxymethyl cellulose. These derivatives were quaternized with either iodomethane, or hydroxypropyl trimethylammonium chloride, or epichlorohydrin and dimethylamine to yield polyquaternary ammonium salts. The focus of this dissertation is the characterization of a family of these compounds based on N,N$\sp\prime$,-dimethylethylene diamine. As these compounds are similar to Polyquaternium 10, a quaternized hydroxyethyl cellulose derivative, the solution properties have been characterized; antimicrobial activity and keratin affinity have …
Evaluation Of Alternative Gases For Immiscible Cyclic Injection., Sara Shayegi
Evaluation Of Alternative Gases For Immiscible Cyclic Injection., Sara Shayegi
LSU Historical Dissertations and Theses
Cyclic gas injection processes have been primarily restricted to the use of pure CO$\sb2$ or CO$\sb2$ that has been slightly contaminated with reservoir gases. However, it is difficult to employ CO$\sb2$ in certain circumstances due to transport, economic, or corrosion problems. This study presents the results of laboratory investigations of the cyclic gas injection process using methane, nitrogen and combinations of these gases with CO$\sb2$. Cyclic gas injections were performed at immiscible conditions in consolidated sandstone cores that contained waterflood residual oil under analogous conditions to previous cyclic CO$\sb2$ injections for comparative purposes. Pure methane recovered approximately the same amount …
On-Line Steady-State Gain Identification For On-Line Optimization Of Multivariable Constrained Chemical Processes., Umesh Kishore Chitnis
On-Line Steady-State Gain Identification For On-Line Optimization Of Multivariable Constrained Chemical Processes., Umesh Kishore Chitnis
LSU Historical Dissertations and Theses
The Amoco Model IV Fluidized Catalytic Cracking Unit (FCCU) (McFarlane et al, 1993) was augmented with Lee & Groves Model (1985) to provide for a simple but realistic product distribution model. This enabled a better and realistic on-line optimization of the FCCU. A Supervisory Multivariable Constrained Optimization (SMCO) algorithm was applied to this augmented model. It was observed that the FCC unit is optimized successfully, without violating any constraints. The parabolic error-penalizing function, incorporated in the algorithm allowed the constraints to asymptotically approach the limits without violating them. The on-line optimization to FCC unit led to maximizing of the feeds, …
Elongational Rheometry Of Coextruded Polymer Melts., Ajit Vijay Pendse
Elongational Rheometry Of Coextruded Polymer Melts., Ajit Vijay Pendse
LSU Historical Dissertations and Theses
In most key polymer processing operations such as fiber spinning, blow molding and extrusion through a converging die, the dominant mode of flow is elongational. Rheological characterization of polymeric materials in elongational flow is critical for material quality control as well as for process modeling applications. Unlike shear flows, which have been studied extensively, elongational flows are not well understood, primarily due to the experimental difficulties involved in generating a pure and steady elongational flow field. There is a dearth of commercially available elongational rheometers in the present rheological literature; those that are commercially available, are useful only at elongational …
The Production And Characterization Of Alginate Produced By Pseudomonas Syringae., Richard David Ashby
The Production And Characterization Of Alginate Produced By Pseudomonas Syringae., Richard David Ashby
LSU Historical Dissertations and Theses
Alginate has many industrial uses because of its unique colloidal behavior, and its ability to thicken, stabilize, emulsify, suspend, form films, and produce gels. Currently, all commercial alginate comes from brown algae, where it exists naturally as a structural material. Many different types of brown algae produce alginate but it can only be obtained in sufficient quantity and quality from a limited number of species. On the basis of location, at least half of the world's resources of this polymer are potentially at risk due either to political instability or industrial pollution. Bacteria provide a potentially unlimited alternate source for …
An Improved Method For The Numerical Simulation Of Multiple Droplet Combustion., Ming-Sheng Chia
An Improved Method For The Numerical Simulation Of Multiple Droplet Combustion., Ming-Sheng Chia
LSU Historical Dissertations and Theses
An improved numerical method suitable for multidroplet calculations has been developed. With this improved method the combustion of droplets in a linear array can be simulated much more efficiently. The improved method is first applied to a viscous flow heat transfer model. In this model, momentum and heat transfer results are obtained for a linear array of an arbitrary number of solid spheres at any Reynolds number. The accuracy, flexibility and efficiency of the new method is shown in this model. The method is then used to include liquid-phase motion and a finite-rate, one-step chemical reaction in the gas phase. …
Control Of One Percent Yield Offset In Reaction Injection Molding., Samuel Mills Peebles
Control Of One Percent Yield Offset In Reaction Injection Molding., Samuel Mills Peebles
LSU Historical Dissertations and Theses
Reaction Injection Molding produces parts that must meet property specifications to be useful. For example a car bumper must have a high impact strength to prevent the car from being damaged during a collision. This research presents a control algorithm that can be implemented to control the part properties of reaction injection molded parts. The part property need not be measurable on line if the property is affected by the reaction conditions within the mold. This is an important feature of the algorithm since many important properties, such as yield strength, cannot be measured without destroying the part. The algorithm …
Modeling Transport Of Non Aqueous Wastes In Unsaturated Soils., Dharmesh Vinaychandra Doshi
Modeling Transport Of Non Aqueous Wastes In Unsaturated Soils., Dharmesh Vinaychandra Doshi
LSU Historical Dissertations and Theses
In evaluating risks associated with chemical spills on the ground surface or leaks from underground storage tanks, it is required to know the extent and degree of contamination in the subsurface. In many cases pure organics are spilled and due to their low miscibility with water they remain pure or concentrated for some distance or time from the source. This dissertation is aimed at developing a model of the multiphase (air, water, organic) migration processes. The particular focus is on modeling organic infiltration in the unsaturated zone where the transport is largely vertical. Sand-column experiments using a variety of immiscible …
An Algorithm For Supervisory Multivariable Constrained Optimization Of Industrial Processes., William E. Daniel Jr
An Algorithm For Supervisory Multivariable Constrained Optimization Of Industrial Processes., William E. Daniel Jr
LSU Historical Dissertations and Theses
An algorithm is presented for supervisory optimization of industrial processes that combines the minimization of operating costs with process operating constraints. The supervisory algorithm manipulates the set points of a lower-level control system and the set points are updated at long enough intervals of time so that the process reaches steady state between set point updates. This steady state assumption greatly simplifies the algorithm computations and, more importantly, significantly reduces the effort required for process identification. This dissertation develops the algorithm and then presents results from its application to a simulated distillation train and reactor feed network. In both applications, …
Mathematical Model Of Hairy Root Growth., Seungdo Kim
Mathematical Model Of Hairy Root Growth., Seungdo Kim
LSU Historical Dissertations and Theses
Hairy roots produce secondary metabolites which have been used as specialty chemicals. The mathematical models of hairy root growth kinetics can guide the design and scale-up of root cultures. An unstructured segregated and a chemically structured segregated models for hairy growth kinetics are formulated with rules of root branching processes. The deterministic branching rule and the stochastic branching rule are studied. For the deterministic rule where two branching parameters are assumed constant, the number of tips can be obtained by solving a linear difference equation. The conceptual framework established for the deterministic rule is used to formulate a stochastic rule …
Soot Suppressing Mechanisms Of Iron In Premixed Hydrocarbon Flames., David Worthington Hahn
Soot Suppressing Mechanisms Of Iron In Premixed Hydrocarbon Flames., David Worthington Hahn
LSU Historical Dissertations and Theses
In-situ light scattering measurements are combined with chemical analysis of sampled soot particles to elucidate the mechanisms through which iron addition affects soot formation and growth processes in fuel-rich, premixed propane and oxygen flames. Soot particle optical inhomogeneity resulting from the addition of iron is accounted for in the light scattering analysis using an effective refractive index model. The influence of iron addition on soot particle diameters, number densities, volume fractions, surface areas, and specific growth rates is investigated. In addition, X-ray photoelectron spectroscopy was used to determine the chemical state of iron species throughout the flame. The analysis revealed …
A Study Of Selected Phenomena Observed During Rotary Kiln Incineration., Christopher Brian Leger
A Study Of Selected Phenomena Observed During Rotary Kiln Incineration., Christopher Brian Leger
LSU Historical Dissertations and Theses
A comprehensive research program is underway at LSU with the ultimate goal of improved understanding and predictive capability for the performance of rotary kiln incinerators. In an extensive experimental study, packs containing toluene-contaminated clay sorbent are batch-fed into the field-scale rotary kiln incinerator of the Louisiana Division of Dow Chemical USA. Water cooled probes are used to obtain continuously gas temperatures and species concentrations within the kiln and afterburner, and existing facility instruments are also monitored. The kiln rotation rate is varied and turbulence air (air injected into the kiln to improve mixing) is added or turned off. Conditions at …
A Novel Process For The Production Of Clinical Dextran., Doman Kim
A Novel Process For The Production Of Clinical Dextran., Doman Kim
LSU Historical Dissertations and Theses
A new process for the production of clinical (or controlled size) dextran was developed. This process is simpler, cheaper and more economical than traditional methods. It involves the use of a mixed culture fermentation with a dextranase producing strain (Lipomyces starkeyi ATCC 74054) and a dextransucrase producing strain (Leuconostoc mesenteroides ATCC 10830). The new process produced 84% (w/w) of theoretical yield clinical dextran with an average polydispersity between 1.2 and 1.5. The mechanism of clinical dextran formation is the competitive production of acceptors from newly formed dextran molecules by dextranase. The acceptors compete for the existing glucosyl portion of sucrose, …
Comparative Evaluation Of Exact Extreme Value Stochastic Flood Model For Mixed Populations., Senarath T. B Ekanayake
Comparative Evaluation Of Exact Extreme Value Stochastic Flood Model For Mixed Populations., Senarath T. B Ekanayake
LSU Historical Dissertations and Theses
Two alternative formulations of the exact extreme value stochastic flood model are presented in explaining the behaviour of observed flood series resulting from mixed climatological processes. As a marginal distribution for flood exceedances, a more flexible Weibull distribution is introduced in the place of the traditional exponential distribution. The asymptotic predictive performances of both the exponential and Weibull model formulations are evaluated in terms of relative bias (BIAS) and relative root mean square error (RMSE) of quantile estimation. The model with Weibull marginal performs well over the exponential for population conditions shown to exist in most of the observed flood …
On Bubble Columns. (Volumes I And Ii)., Nicholas William Geary
On Bubble Columns. (Volumes I And Ii)., Nicholas William Geary
LSU Historical Dissertations and Theses
There exists a narrow operating window in bubble columns where the motion is so gentle that the normally dominating forces of coalescence and breakup no longer define column conditions. This behavior is synonymous with operation in the bubbly flow regime. During experimentation, two distinct hydrodynamic regions were observed; close to the sparger, the liquid was well mixed, whilst in the remainder of the column a dispersive flow model was determined to be appropriate. In the entrance zone, the isotropic turbulence theories of Kolmogoroff adequately represented transport behavior. This finding implies that a churn-turbulent environment, wherein bubbles are continuously reformed, will …
Feedback Linearization Of Nonlinear Systems: Robustness And Adaptive Control., Weon Ho Kim
Feedback Linearization Of Nonlinear Systems: Robustness And Adaptive Control., Weon Ho Kim
LSU Historical Dissertations and Theses
Feedback linearization provides an effective means of designing nonlinear control systems. This method permits one to have an exactly equivalent linear system by using a coordinate transformation and state feedback. Once the nonlinear system is transformed to a linear system, one can proceed with well developed control technologies for linear systems. Feedback linearization is based on a model of the real system. If there is mismatch between the model and the real plant, feedback linearization does not yield an exactly linear system. The question of robustness then arises: will a controller based on the model be stable when applied to …
A Study On The Effects Of Additives On Selective Hydrogenation Of Trace Acetylene Over Palladium Catalysts., Yeung Ho Park
A Study On The Effects Of Additives On Selective Hydrogenation Of Trace Acetylene Over Palladium Catalysts., Yeung Ho Park
LSU Historical Dissertations and Theses
The effects of both carbon monoxide (as a gas phase additive) and potassium (as a catalyst additive) on the selective hydrogenation of acetylene over Pd/Al$\sb2$O$\sb3$ was studied by deuterium tracer experiments combined with Kemball's steady-state treatment and temperature programmed reaction (TPR). The TPR of acetylene and ethylene in hydrogen, which was attempted in this study for the first time, enabled the investigation of the behavior of the adsorbed species on Pd. CO addition to the reaction mixture significantly increased the probability of ethylene desorption during ethylene deuteration while minor effects due to CO displacement of hydrogen were observed for acetylene …
Interfacial Adhesion In Rayon/Nylon Sheath/Core Composite Fibers., Weiying Tao
Interfacial Adhesion In Rayon/Nylon Sheath/Core Composite Fibers., Weiying Tao
LSU Historical Dissertations and Theses
Rayon/nylon sheath/core composite fibers with enhanced adhesion were produced using a wire coating type process. One objective of this research was to determine an effective coupling agent and the most appropriate application conditions for maximum interfacial adhesion in the rayon/nylon bicomponent fibers. The second objective was to characterize the interfacial adhesion between the core fiber and the rayon skin. It was found that fumaric acid (FA) was an effective adhesion promotor for rayon/nylon composite fibers since it has difunctionality and steric hinderance necessary to form covalent bonds to both layers. After removal of the spin finish by water washing the …
Low-Pressure Phase Equilibria Of Heavy Aromatic Compounds., Ajay Gupta
Low-Pressure Phase Equilibria Of Heavy Aromatic Compounds., Ajay Gupta
LSU Historical Dissertations and Theses
Phase equilibrium diagrams for systems containing compounds found in coal liquids and heavy crude oil are useful in designing separation processes and also in testing and developing of thermodynamic models. Solid-liquid equilibrium (SLE) data are easy to obtain compared with vapor-liquid equilibrium (VLE) data for systems that are solid near room temperature, because the solids melt to liquids and have relatively high boiling points. It may be possible to extrapolate activity coefficients derived from SLE data to higher temperatures and thus predict vapor-liquid equilibrium. This dissertation presents new SLE and VLE data for compounds related to coal liquids. The problem …