Chemical Engineering Commons^™

Microbial Biofilm Development And Electron Transfer In Electrochemical Systems, Jose Cornejo

Chemical and Biological Engineering ETDs

Energy harvesting from microorganisms has created vibrant research efforts for the past 20 years that has lead to the development of emerging topics such as microbial electrochemistry, biofilm formation in electrochemical systems and alternative energy technologies applied in environmental processes. In this study we present procedures that aim for further understanding of bacterial physiological conditions in electrochemical systems and interactions between biofilms and solid surfaces, particularly, for the facultative anaerobe Shewanella oneidensis MR-1. These systems consist of microbial fuel cells (MFCs) whose anode component will be evaluated with regards to performance, electrical current generation, and microbial coverage and biofilm development. …

The Influence Of Season, Heating Mode And Slope Angle On Wildland Fire Behavior, Jonathan R. Gallacher

Theses and Dissertations

Wildland fire behavior research in the last 100 years has largely focused on understanding the physical phenomena behind fire spread and on developing models that can predict fire behavior. Research advances in the areas of live-fuel combustion and combustion modeling have highlighted several weaknesses in the current approach to fire research. Some of those areas include poor characterization of solid fuels in combustion modeling, a lack of understanding of the dominant heat transfer mechanisms in fire spread, a lack of understanding regarding the theory of live-fuel combustion, and a lack of understanding regarding the behavior of flames near slopes. In …

Enhanced Cycle Life And Capacity Retention Of Iron Oxide Ultrathin Film Coated Sno₂ Nanoparticles At High Current Densities, Sai Abhishek Palaparty, Rajankumar L. Patel, Xinhua Liang

Chemical and Biochemical Engineering Faculty Research & Creative Works

Tin oxide (SnO₂) has a high theoretical capacity (∼782 mA h g^-1), but it experiences large volume changes during charge and discharge cycles that cause rapid capacity fade, which limits its practical use as an anode material. In an attempt to solve this, we coated these particles with ultrathin electrochemically active iron oxide (FeO_x) films that act as an artificial solid electrolyte interphase layer, thus stabilizing the SnO₂ particles for better longevity of significantly improved performance at high current densities in a practical voltage window. Since there exists a tradeoff between species transport …

Characterization Of Silica-Based And Borate-Based, Titanium-Containing Bioactive Glasses For Coating Metallic Implants, Omar Rodriguez, Declan J. Curran, Marcello Papini, Lana M. Placek, Anthony W. Wren, Emil H. Schemitsch, Paul Zalzal, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Bioactive glasses have found applications in diverse fields, including orthopedics and dentistry, where they have been utilized for the fixation of bone and teeth and as scaffolds for drug delivery. The present work outlines the characterization of two novel titanium-containing glass series, one silica-based and one borate-based. For the silica-based series, titanium is added at the expense of silicon dioxide whereas for the borate-based series, it is added at the expense of boron oxide as confirmed by Energy Dispersive Spectroscopy. Amorphous structures are obtained for silica-based glass at 15 mol% TiO₂ and for borate-based glasses at 0 mol% and …

Composition And Manufacturing Effects On Electrical Properties Of Li/Fes2 Thermal Battery Cathodes, Emilee Lolita Reinholz

Chemical and Biological Engineering ETDs

Li/FeS2 thermal batteries provide a stable, robust, and reliable power source capable of long-term electrical energy storage without performance degradation. These systems rely on a eutectic salt that melts at elevated temperature, activating the cell. When the electrolyte melts, the cathode becomes a suspension, with cathode particles suspended in a molten salt. The suspension experiences mechanical deformation, or slumping.' This slump changes the mechanical compression of the cell, as well as the tortuosity and electronic and ionic conductivity of the cell as the cathode mesostructure is reordered in response to the external compressive stress. The combined effect of deformation, component …

Laboratory Studies Of The Biodegradation Of Chemically Dispersed Oil: Effect Of Droplet Size And Nutrient Amendment, Christopher D'Ambrose

Dissertations

Oil spills could have devastating effects on the shorelines, and for this reason, chemical dispersants are commonly used to disperse the oil slick in the water column, preventing it from reaching the shorelines. However, the long term fate of dispersed oil depends on its biodegradation by indigenous microorganisms, which in turn depends on the concentration of nutrients in water and on the droplet size distribution.

Using water from the shorelines of Atlantic City, we placed the water with oil and dispersant inside EPA Baffled Flasks and placed them on rotatory shakers. We selected two speeds: high (250 rpm) and low …

Synthesis Of A Renewable Sourced Thermotropic Polyester With 2,5-Furandicarboxylic Acid, Alicia Marie Marguerite Hurst

Theses

With the rapid depletion of non-renewable sourced materials, unpredictable fluctuations in the prices of fossil fuels, and increased environmental awareness the need to develop biobased materials grows ever more desperate. Furan derivatives sourced from hexoses provide a promising solution for replacing petrochemical based materials. One furan derivative in particular, 2,5-furandicarboxylic acid (FDCA), is especially promising due to its structural similarity to terephthalic acid and potential for use in the production of polyesters similar to PET, PPT, and PBT. This study investigated the synthesis, thermal and liquid crystalline properties of a totally renewable sourced thermotropic polyester based on FDCA. Fructose was …

Computational And Experimental Determination Of The Hydrodynamics In A Stirred Unbaffled Vessel Provided With Angle-Mounted Axial Impellers, Ji Ma

Theses

In most industrial applications, stirred tanks and reactors are typically provided with baffles to improve their mixing characteristics. However, in a number of pharmaceutical production facilities unbaffled vessels are commonly used. The absence of baffles is preferred in such cases because it reduces the potential for contamination and makes cleaning the vessel between batches easier. However, the lack of baffles also has a negative impact on the system’s hydrodynamics since it often results in poor mixing of the batch, especially if the impeller is centrally placed, since the liquid in such a system is subject to a strong tangential flow, …

A Preliminary Investigation Of The Sterile-Filterability Of Bcs Class Ii Drug Nanosuspensions Prepared Via Wet Stirred Media Milling, Parul Ohri

Theses

Drug nanoparticles can achieve targeting capabilities, enhanced dissolution rates and improved bioavailability when injected intravenously. Sterile filtration of drug nanoparticle suspensions (nanosuspensions) is critically needed for administration by intravenous delivery route. Avoiding gamma irradiation and high temperatures, sterile filtration could be an effective process to sterilize drug nanosuspensions. On the other hand, two major challenges must be tackled: drug particles must at least be smaller than the filter pore size and minimum amount of non-toxic stabilizers must be used to prevent side effects like pain on the injection site. The aim of this study is to prepare naproxen (NPX) nanosuspensions …

Development Of Pvdf Membrane Nanocomposites Via Various Functionalization Approaches For Environmental Applications, Douglas M. Davenport, Minghui Gui, Lindell E. Ormsbee, Dibakar Bhattacharyya

Chemical and Materials Engineering Faculty Publications

Membranes are finding wide applications in various fields spanning biological, water, and energy areas. Synthesis of membranes to provide tunable flux, metal sorption, and catalysis has been done through pore functionalization of microfiltration (MF) type membranes with responsive behavior. This methodology provides an opportunity to improve synthetic membrane performance via polymer fabrication and surface modification. By optimizing the polymer coagulation conditions in phase inversion fabrication, spongy polyvinylidene fluoride (PVDF) membranes with high porosity and large internal pore volume were created in lab and full scale. This robust membrane shows a promising mechanical strength as well as high capacity for loading …

Sustainable P2 Design For Batch-Based Specialty Chemical Manufacture, Brigitte Pastore

Theses and Dissertations

A case study has been conducted on the reduction of n-methyl-2-pyrrilodone (NMP) solvent waste in the manufacture of polyimide and polybenzoxazole precursors. The evaluation includes the environmental and economic assessment of solvent recovery and substitution strategies. A two-step distillation process proved effective in recovering 95% of the NMP at a purity of 99.97% from the aqueous solvent waste stream. Yearly operating costs were reduced by 83% and total life cycle emissions were reduced by 44%, due to reduction in virgin NMP use and hazardous waste disposal. With capital acquisition, the recovery option would still result in a net present value …

Voltammetric Analysis Of Mixtures Of Molten Eutectic Licl-Kcl Containing Lacl3 And Thcl4 For Concentration And Diffusion Coefficient Measurement, Zhong-Hang Wang, Devin Rappleye, Michael F. Simpson

Faculty Publications

Several electrochemical techniques, including cyclic voltammetry (CV), chronopotentiometry-open circuit potential (CP-OCP), chronoamperometry (CA) and normal pulse voltammetry (NPV) were applied to the eutectic LiCl-KCl melt containing LaCl₃ and ThCl₄ at 773K. The dependence of diffusion coefficient of La(III) on concentration of LaCl₃ was investigated by using CV, CP and CA. As the concentration of LaCl3 increases, the D_La(III) value obtained from CV gradually decreases, while the values derived from CA and CP exhibit a dome-shaped variation trend. In the LiCl-KCl-LaCl₃-ThCl₄ system, the diffusion coefficients of La(III) and Th(IV) are both approximately constant …

Effect Of Spalled Particles Thermal Degradation On A Hypersonic Flow Field Environment, Raghava S. C. Davuluri, Huaibao Zhang, Alexandre Martin

Mechanical Engineering Faculty Publications

Two-way coupling is performed between a spallation code and a hypersonic aerothermodynamics CFD solver to evaluate the effect of spalled particles on the flow field. Time accurate solutions are computed in argon and air flow fields. A single particle simulations and multiple particles simulations are performed and studied. The results show that the carbon vapor released by spalled particles tend to change the composition of the flow field, particularly the upstream region of the shock.

Methane Emissions As Energy Reservoir: Context, Scope, Causes And Mitigation Strategies, Xiaoli Chai, David J. Tonjes, Devinder Mahajan

Technology & Society Faculty Publications

Methane (CH4) is now considered a bridge fuel between present fossil (carbon) economy and desired renewables and this energy molecule is projected to play an important role in the global energy mix well beyond 2035. The atmospheric warming potential of CH4 is 28-36 times, when averaged over a 100-year period, that of carbon dioxide (CO2) and this necessitates a close scrutiny of global CH4 emissions inventory. As the second most abundant greenhouse gas (GHG), the annual global CH4 emissions were 645 million metric tons (MMT), accounting for 14.3% of the global anthropogenic GHG emissions. Of this, five key anthropogenic sources: …

Champions’ Summer Defense: Manufacturing All-Natural Equine Spray, Brooke Riggs, Peter Rinaldi, Zach Taylor

Capstone Design Expo Posters

Research was conducted in 2014 and 2015 for the development of Champions’ Summer Defense, an all-natural product to protect horses from irritating and potentially harmful summer elements. This formulation provides sunscreen to protect the horses from sunburn and reduces coat bleaching. In addition, this spray acts as a conditioner and leaves the horse’s coat shiny by fighting dry skin and moisturizing the coat. Champions’ Summer Defense’s unique formulation is naturally antimicrobial, eliminating the need for a preservative and allows the product to be 100% natural. The antimicrobial property will also help prevent skin irritations from insects and will keep the …

Polyether Product Recovery: Salt-Induced Water-Polymer Separation, Carolina Andrea Mercado Buelvas, Chance Parrish, Rohit Sharma

Capstone Design Expo Posters

Evonik Industries currently loses approximately 50 tons of polyether product to wastewater washes annually. Evonik has requested an industrially viable solution to maximize the recovery of the lost product in the current process. It was required that the solution have a one year payback period, and be in compliance with current regulatory policies. Literature sources showed that salt is a commonly used agent to force the separation of polyether-water mixtures. Using this information, a method was developed using a salt already present in the process to induce a phase separation and to recover the polyether. An empirical multilinear refractive index …

Smart Medication Disposal: Subcritical Water Oxidation Of Pharmaceutical Compounds, Sharon Veeravalli, Charles Fricke, F. William Ronnau

Capstone Design Expo Posters

Disposal of unused or expired pharmaceuticals is neither safe nor environmentally-friendly. Current regulations for pharmaceutical disposal do not prevent environmental contamination. Industrial methods of disposing of waste medications can generate toxic compounds through incineration, or generate large volumes of waste through use of physical adsorbents. Medium sized providers (pharmacies, small clinics) typically hire expensive hazardous waste removal or dispose of these medications improperly.

The project goal is to deliver a safe, sustainable process, suitable for retail pharmacies and the like, for rendering pharmaceuticals chemically inactive. This project encompasses the development of a degradation process via testing of 5 model pharmaceuticals …

Development Of A Tabletop Soft Gel Encapsulation Machine, Amanda Carter, Lara Hamid, Harini Muralikrishnan, Bethlehem Solomon

Capstone Design Expo Posters

This VCU Chemical and Life Science Engineering student team is designing a tabletop gel encapsulation machine to produce ~50 capsules per minute enabling rapid changeover for research and development purposes for Pfizer Consumer Healthcare. The preliminary design is based on reverse engineering of the large-scale encapsulation machine. Building from an initial prototype that included die rolls with variable rotation speed control and temperature control, the team identified and designed additional components to produce soft gel capsules: (1) producing gelatin ribbons from molten gelatin, (2) synchronizing the injection of medicine and capsule formation, and (3) ensuring that the capsules seal properly. …

Nanoparticles As Lubricant Additives, Jacob Miller, Rayyan Alsinan, Zainab Suwaiket, Samuel Wojcicki

Capstone Design Expo Posters

Nanoparticles have generated interest in the oil industry as potential additives. Many nanoparticles have been shown to improve fuel economy and engine efficiency. However, there are an infinite number of nanoparticle formulations, and to test all these would be impossible. The objective of this project was to develop a predictive model which demonstrates the impact of factors such as size, concentration, and hardness on the performance of nanoparticles as oil additives.

The concentrations tested were 0.01% and 0.5% by mass in PAO4 base oil. The sizes tested were 5-15nm and 20-50nm. Using four compositions to approximate hardness, a 4 x …

Treatment Of Menorrhagia And Irregular Menstruation: Cryo-Fluid Ablation Of The Endometrium, Baha Endisha, Benjamin Green

Capstone Design Expo Posters

Menorrhagia and irregular menstruation, characterized as dysfunctional uterine bleeding (DUB), is a condition that affects 15 to 20% of reproductive and pre-menopausal women. Common treatments are invasive, painful, or have low success rates; there is a need for new treatment. A 2014-2015 senior design team developed a prototype treatment based on the hypothesis that if free fluid was circulated in the uterine cavity at temperatures between 0 and -15ᵒC, cell death of the 2cm reproductive endometrial layer in the uterine cavity could be achieved and induce long term amenorrhea. The current senior design team significantly modified the prototype to reach …