Engineering Commons^™

Modulation Of Bone And Nerve Cell Behavior Using Biodegradable Polymer Networks, Lei Cai

Doctoral Dissertations

This dissertation presents novel biodegradable and photo-crosslinkable building blocks to achieve polymer networks with controlled surface chemistry, stiffness, and topographical features for investigating cell-material interactions and targeting hard and soft tissue engineering applications. Chapter I reviews the recent progress in polymeric gel systems and how their physical properties can be tailored to regulate cell functions and satisfy the clinical needs. Chapter II presents a facile method to synthesize photo-crosslinkable poly(epsilon-caprolactone) acrylates (PCLAs) and reveal tunable cell responses to photo-crosslinked PCLAs. Chapter III investigates the mechanism of colorization in preparing crosslinkable polymers by reacting hydroxyl-containing polymers with unsaturated anhydrides or acyl …

The Synthesis And Characterization Of Novel Group 13 Nanostructured Building Block Heterogeneous Silicate Catalysts, Joshua G. Abbott

Doctoral Dissertations

A building block approach and sequential addition methodology were utilized to prepare heterogeneous silicate catalysts containing atomically dispersed group 13 metal (B, Al, Ga) centers. The octa(trimethyltin) silsequioxane, Si8[sub]O12[sub](OSnMe3[sub])8[sub], was used as the building block for the synthesis of these materials. Reaction of the building block with a variety of group 13 metal chlorides led to the formation of cross-linked matrices. All prepared materials were characterized by gravimetric analysis, gas absorption, IR, and NMR. In addition, aluminum and boron samples where characterized by 27[sup]Al and 11[sup]B solid state NMR, and gallium samples were studied using x-ray absorption techniques.

Studies found …

Meso-Scale Fluidic Devices With Chemical Sensors For Biological Applications, Satya Gowthami Achanta

Doctoral Dissertations

"Molecular oxygen and humidity are some of the major environmental quantities being measured for various industrial and commercial applications. This dissertation focuses on the design, fabrication and characterization of optofluidic biosensor systems for oxygen and humidity quantification using color charge-coupled device (CCD) camera as a photodetector and LED panel as an excitation source. Meso-scale fluidic devices with integrated oxygen and humidity sensors for potential applications to hydrotropic and oxytropic studies of small plant roots have been investigated in this study. Meso-scale sensor platform was fabricated using porphyrine complex as the sensitive dye embedded within Ethyl Cellulose (EC) polymer matrix. Green …

Numerical Simulations Of Fracture Propagation And Sealing: Implications For Wellbore Strengthening, Saeed Salehi

Doctoral Dissertations

"To mitigate the small tolerance between pore pressure and fracture gradients an engineering practice referred to as "wellbore strengthening" is conducted to increase the fracture gradient. The method relies on propping and/or sealing the fractures with specially designed materials. Different competing theories exist for physical wellbore strengthening mechanisms which can be categorized into two groups. The first group explains that strengthening happens as a result of increasing wellbore hoop stress when fractures are sealed while the second group emphasis is on fracture tip isolation with suitable materials and enhancing fracture propagation pressure. The numerical models and lab experiments …

Modeling Carbon Sequestration In Transition Zone To Optimize Storage Potential, Fang Yang

Doctoral Dissertations

"Shallow aquifers are potential candidates for carbon sequestration because of their wide distribution and low injection cost. Injected CO₂ in a shallow region segregates into two zones according to CO₂ phases within the initial reservoir pressure and the maximum bottom hole pressure: gas zone and transition zone. Transition zone is a better option because of favorable CO₂ properties. This work investigated the CO₂ storage potential in transition zone using the compositional simulator CMG-GEM and a design of experiment software iSIGHT. First, it addressed the basic characteristics of CO₂ sequestration in transition zone, and then modeled CO₂ injection with simultaneous water …

Investigation Of Wellbore Stability In A North Sea Field Development, Steven Austin Hilgedick

Doctoral Dissertations

"Planning drilling operations is key to the development of oil and natural gas fields. As part of well design, wellbore stability and pore pressure analysis are main factors in determining the safe operating window for selecting mud density. The motivation for this research was to conduct wellbore stability based on exploration wells as basis for planning new offshore field developments with deviated and horizontal wells. A second objective was to investigate the use of a probabilistic approach to wellbore stability, and compare it to the conventional deterministic methods, in order to evaluate the value of including a probabilistic approach to …

The Effect Of Supercritical Water On Crude Glycerin Solution, Jared Bouquet

Doctoral Dissertations

"Crude glycerin solution, a principal byproduct of the conventional biodiesel process, was reacted in supercritical water using a specially designed Haynesʼ Alloy 282 reactor system for the production of hydrogen rich syngas. The effects of temperature, pressure, water-to-carbon molar ratio, reactor residence time, and glycerin-to-methanol weight ratio on the extent of carbon gasification and gas composition were explored. Based on the results, the extent and selectivity of reactions that concurrently occur when methanol and glycerin are in the presence of supercritical water were analyzed. A decomposition reaction pathway for glycerin conversion to syngas was hypothesized, and then utilizing the results …

Organoclay Dispersion In Linear Low-Density Polyethylene And Maleated Linear Low-Density Polyethylene Via Supercritical Carbon Dioxide Processing, Matthew J. Factor

Doctoral Dissertations

"Research into polymer-clay nanocomposites (PCN's) has been ongoing for decades as a result of the property enhancements offered by clay. To fully exploit these property enhancements, organically modified clays (organoclays) are utilized to promote clay delamination by reducing the disparity between the hydrophilicity of the clay and the hydrophobicity of the highly used polyolefin polymer. Since the organic modification of organoclays can degrade at temperatures typical to many polymers during melt-mix processing, this work utilizes the low-temperature processing fluid supercritical carbon dioxide (scCO₂) to disperse an organoclay into the highly used polymer LLDPE and ascertains the associated processing conditions for …

Updated Eor Screening Criteria And Modeling The Impacts Of Water Salinity Changes On Oil Recovery, Ahmad Aladasani

Doctoral Dissertations

"Developing technologies for enhanced oil recovery (EOR) from existing oil fields would supply the world's energy needs for several decades. The application of EOR in many major oil-producing countries remains in its conceptual stage. Thermal and gas EOR methods achieve high incremental rates; however, their application range has not broadened significantly as they have matured, while the rate at which new, promising EOR methods such as Low-salinity water flooding (LSWF) are being implemented is alarming. Despite, the potential of LSWF its development and application has been hindered by the lack of consensus concerning its recovery mechanism(s). Every oil reservoir has …

Free-Radical Maleation Of Poly(Butylene Adipate-Co-Terephthalate) In Supercritical Carbon Dioxide And Its Effect On The Percolation And Deformation Mechanism Of Layered Silicate Nanocomposites, Alexandria Niemoeller

Doctoral Dissertations

The utilization of compostable polymers such as poly(butylene adipate-co-terephthalate) (PBAT) in single-use packaging applications can mitigate the water, solvents, and energy required for processing plastic waste. PBAT exhibits exceptional elongational properties, but its moderate water vapor permeability and low tensile modulus limit the applications in which PBAT can be employed. In this work, PBAT nanocomposites were produced at various loadings of organically-modified montmorillonite. The secondary structure of nanoparticles formed within the PBAT matrix was evident in the terminal region of the linear viscoelastic response under oscillatory shear, and a percolation threshold was determined to occur at 3.88% clay by weight. …

Glycerin Reformation In High Temperature And Pressure Water, Jason W. Picou

Doctoral Dissertations

"The noncatalytic reformation of glycerin in supercritical water was studied in a Haynes 282 tubular reactor. In order to determine which parameters were the most influential, a 2³ experimental matrix was conducted, with temperatures of 500 and 700⁰C, water/glycerin molar ratios of 3:1 and 13:1, and residence times of 30 and 90 seconds, all at a pressure of 24 MPa. It was found that temperature had the largest effect on the two gasification parameters deemed most important, gasification percentage and hydrogen yield. Based on this, the effect of temperature was further investigated by looking at 5⁰C intervals from 500 to …

Global Homotopy Continuation And Stability Analysis: Optimal Application To Chemical Engineering Design, David Anthony Harney

Doctoral Dissertations

"The design of chemical engineering process equipment routinely necessitates the solution of large systems of non-linear equations. The processing speed of standard desktop computers have allowed for equation-oriented process simulators to become commercially viable. For a fully equation-oriented simulator to be competitive with standard iterative solvers, a robust and reliable non-linear equation solver is required and standard Newton methods fail to provide the necessary reliability.

Homotopy continuation methods have been proposed as a way to greatly expand the domain of convergence of the process simulator's equation solving algorithm. This research expands upon existing homotopy continuation algorithms, investigates bounding algorithms, corrector …

A Methodology For Statistical Propped Fracture Treatment Design In Fluvial Environments, Prue Elizabeth Smith

Doctoral Dissertations

"Treatment design for hydraulic fracturing historically has been deterministic in nature. In a deterministic design, required variables can be determined and are assumed to be laterally continuous. This is difficult for geologic settings in general, but nearly impossible in fluvial geologic environments where the second assumption is violated.

Recent work has employed statistical methods to account for the complexity and heterogeneity in fluvial environments. Statistical design tools have been used to assist with improving the design process in complex fluvial geologic systems. Currently, the statistical design tools must be created using a "trial and error" process, which requires first completing/fracturing …