Chemical Engineering Commons^™

Higher Tensile Forces Across Cellular Junctions And An Intact Nuclear Linc Complex Is Required For Epithelial Function And Stability, Fnu Vani Narayanan

Theses and Dissertations

Recent advances in three-dimensional (3D) cell culture systems have provided key insights into the understanding of biochemical and physiological states of native tissue. A significant progress in the field of mechanobiology involves measuring cellular traction forces in a more native 3D environment. However, the effects of mechanical forces exerted across cellular junctions and the nuclear LINC complex, in an organized 3D system has not been investigated thus far. Epithelial cells spontaneously form acini (also known as cysts or spheroids) with a single, fluid-filled central lumen, when grown in 3D matrices. The size of the lumen is dependent on apical secretion …

Beneficiation Of Coal Using Supercritical Water And Carbon Dioxide Extraction, Matthew Decuir Virginia Commonwealth University Cl

Theses and Dissertations

This work explores the use of carbon dioxide, water, and their mixtures as solvent for the pre-combustion beneficiation of raw coal without using any toxic mineral acids in the temperature range of 200-400℃. The fluid polarity, ionic constant, and supercritical point can be adjusted by H₂O/CO₂ ratio and temperature. Adding carbon dioxide to hydrothermal fluid also increases the ionization by forming carbonic acid. Extractions with supercritical fluids have several benefits including enhanced mass transport, ease of separation and recycle, wide range of extractive capability and tunability, better inherent safety, and in the case of carbon dioxide and …

Self-Assembled Metal Nanoparticle/Polymer Nanocomposites As Nanoreactors For One-Pot Reactions, Andrew Harrison

Theses and Dissertations

Polymer nanoreactors incorporating gold nanoparticle catalysts were self-assembled via Flash Nanoprecipitation. The incorporated gold nanoparticles maintained catalytic activity, which was evaluated using reduction of 4-nitrophenol with sodium borohydride as a model reaction. The diffusion coefficient for 4-nitrophenol was determined by NMR and used to calculate the second Damköhler number, which indicated that the systems were not diffusion limited. Despite similar diffusion coefficients, catalytic performance was strongly affected by the co-precipitant. For example, the apparent reaction rate per surface area using castor oil was over 8-fold greater than polystyrene. Thus, we measured the partition coefficient of 4-nitrophenol between water and castor …

Comparison Of Pyrolysis Of Live Wildland Fuels Heated By Radiation Vs. Convection, Mohammad-Saeed Safdari, Elham Amini, David R. Weise, Thomas H. Fletcher

Faculty Publications

During wildland fires, which include both planned (prescribed fire) and unplanned (wildfire) fires, live and dead plants may be subject to both radiative and convective heat transfer mechanisms. In this study, the pyrolysis of 14 live plant species native to the forests of the southern United States was investigated using a flat-flame burner (FFB) apparatus under three heating modes in order to mimic pyrolysis of plants during wildland fires. The heating modes were: (1) radiation-only, where the plants were pyrolyzed under a moderate heating rate of 4 °C s−1 (radiative flux of 50 kW m−2); (2) convection-only, where the FFB …

Modeling The Influence Of Changes In Aliphatic Structure On Char Surface Area During Coal Pyrolysis, He Yang, Thomas H. Fletcher, Yang Li, Lijun Jin, Sufen Li, Yan Shang, Haoquan Hu

Faculty Publications

The influence of changes in aliphatic structure on char surface area during coal pyrolysis was modeled, and the effect was introduced to a previous char surface area model for lignite pyrolysis established based on the chemical percolation devolatilization (CPD) model. The modified model can predict not only the N2 and CO2 char surface area during rapid pyrolysis of three lignites but also the CO2 char surface area of two high-volatile bituminous coals; the agreement of the modified model with experiments is improved at high temperatures. The decrease in aliphatic chain length can reduce adsorption positions around aromatic core, and decrease …

Fabrication Of Micro-/Nanofluidic Models And Their Applications For Enhanced Oil Recovery Mechanism Study, Yandong Zhang

Doctoral Dissertations

”Micro-/nanofluidic model, as a potential powerful tool, has been used for decades for investigating fluid flow at pore-scale in energy field. It is still increasingly imperative nowadays to use different micromodels to direct observe pore-level fluid flow and analyze mechanisms of different enhanced oil recovery methods. In this work, three main tasks including three dimensional micromodels (1D,2D,3D) are proposed to fabricate and use for investigating different mechanisms of different enhanced oil recovery methods. For 1D capillary tube micromodel, we fabricate and use it to investigate the dynamics of a trapped oil droplet under seismic vibration. Seismic stimulation is a promising …

A Review Of Carbon Dioxide Adsorption To Unconventional Shale Rocks Methodology, Measurement, And Calculation, Sherif Fakher, Abdulmohsin Imqam

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Carbon dioxide (CO₂) injection has been applied extensively in hydrocarbon reservoirs for both increasing oil recovery and CO₂ storage purposes. Recently, CO₂ injection has been proposed to increase oil recovery and for CO₂ storage in shale reservoirs. During CO₂ injection in shale reservoirs, adsorption will take place on the surface of the rock, which will impact both the oil recovery and the storage capacity. This research provides a roadmap to the different types of adsorption and the adsorption measurements and calculations with emphasis on the ones most applicable during CO₂ injection in shale …

Wastewater Treatment Fatty Acids For Biodiesel Production, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Wastewater scum is the thick oily substance that floats on top of the primary and secondary tanks within a wastewater treatment plant. Scum has a 30% to 60% lipid content making it an excellent resource for the biodiesel industry. Also the use of scum would reduce the cost of current management practices such as landfill disposal or incineration. In this article there is an overview of lipid byproducts currently being produced at wastewater treatment plants today. This is followed by a presentation showing a full length process for turning wastewater scum into biodiesel raw material.

Synthesis And Characterization Of Pvp Based Catalysts For Selected Application In Catalysis, Hany A. Elazab, Mohamed N. Ayad, Mohamed M. Hammam, Mostafa A. Radwan, Mohamed A. Sadek

Chemical and Biochemical Engineering Faculty Research & Creative Works

This research aims to study the catalyst activity in specific reactions and the characteristics of the catalyst in order to optimize its performance. This research investigates PVP based catalysts and their properties and applications. PVP was prepared in combination with different metal oxides in order to be tested for different catalytic applications including dye removal. Methyl orange was used as a dye and different concentrations were tested against different metallic ions in order to optimize the catalyst for being used in dye removal applications. Spectrophotometer was used to calculate the concentration of the dye before and after catalyst exposure and …

Factors Impacting The Transport And Enhanced Oil Recovery Potential Of Polymeric Nanogel In Sandstone, Haifeng Ding

Doctoral Dissertations

"Enhanced oil recovery (EOR) using nanometer-sized particles has drawn great attention in the oil industry because of their various advantages brought by size. However, their applications on a field scale are very limited, especially for deformable nanoparticles. The objective of this research is to explore the transport behavior of deformable polymeric nanoparticles (nanogel), the factors impacting these behavior, and their EOR potentials. First, 240 published nanoparticle core flooding experiment data were collected and analyzed about the extent to what the nanoparticles can improve oil recovery. Results show that on the laboratory scale the incremental oil recovery could be as high …

Studies On The Stability Of Plasma Proteins And Their Fragments, Paul Praveen Nakka

Doctoral Dissertations

“The stability of a protein-based biological drug is an important concern during processing, storage or patient administration. There are various forces which contribute to the stabilizing of proteins. Both hydrogen bonds and hydrophobic interactions play an important role in protein stability. Improper folding or misfolding of proteins leads to aggregation, which is a major problem found in the bioprocessing industry. The objectives of this research are: 1) to determine the effect of environmental factors such as pH, temperature, additives or salts, and cosolvents on the stability human serum albumin (HAS), which is the most abundant protein in plasma, 2) to …

Development Of Novel Materials And Processes For Direct Conversion Of Co₂ Flue Gas To Chemicals And Fuels, Ahmed Al-Mamoori

Doctoral Dissertations

“This research focused on addressing the pressing issues of greenhouse gas emissions that greatly contribute to climate change. Specifically, the focus was given to the reduction of anthropogenic CO₂ emission and its subsequent conversion to commodity chemicals and fuels. In the first part of the research, a series of novel high temperature CO₂ adsorbents including double salts (K-Ca and Na-Ca) and metal-doped calcium oxide (Fe_x@CaO and Ga_x@CaO) was developed and evaluated. Both sets of materials exhibited high CO₂ capacity, fast kinetics, and long-term stability. In particular, at 650 °C, the doped adsorbents comprising …

Comprehensive Study Of Bio-Diesel Continuous Flow Synthesis, Aso A. Hassan

Doctoral Dissertations

“Energy has become an indispensable factor in preserving economic growth since the commencement of the industrial revolution. In recent years, biodiesel has gained acceptance as a notable alternative to the widely used petroleum-derived diesel fuel because it is biodegradable, non-toxic, and generates fewer exhaust pollutants. Recently, biodiesel studies have focused on the development of process intensification technologies to resolve some technical challenges facing biodiesel production, such as long residence times and catalyst sensitivity. These intensification technologies enhance process mass/heat transfer to achieve a continuous, scalable process that can be easily transported to utilize locally available feed stocks. Five phases have …

Experimental Study On A Novel Eor Method -- Polymeric Nanogel Combined With Surfactant And Low Salinity Water Flooding To Enhance Oil Recovery, Mustafa M. Almahfood

Doctoral Dissertations

“Extracting higher amounts of oil from current reservoirs is a necessity for the oil industry to enhance their profitability and sustainability. The desire to recover more oil from the existing reservoirs has led to a growing interest of nanoparticle application in enhanced oil recovery (EOR). However, most researchers have focused on the evaluation and surface modification of non-deformable nanoparticles. This dissertation evaluates the potential of deformable nanogel particles as an EOR material when they are combined with two other promising technologies - surfactant and low salinity water floodings. The particle size distribution, ζ-potential and interfacial tension were measured for a …

An Integrated Wellbore Stability Study To Mitigate Expensive Wellbore Instability Problems While Drilling Into Zubair Shale/Sand Sequence, Southern Iraq, Ahmed Khudhair Abbas

Doctoral Dissertations

”The Zubair Formation is the most prolific reservoir in Iraq, which is comprised of sandstones interbedded with shale sequences. Due to the weak nature of the shale sequence, the instability of a wellbore is one of the most critical challenges that continuously appears during drilling across this formation. Historically, over 90% of wellbore problems in the Zubair Formation were due to wellbore instability. Problems associated with wellbore instability, such as tight hole, shale caving, stuck logging tools along with subsequent fishing, stuck pipe, and sidetracking result in increasing the non-productive time. This non-productive time has cost an enormous amount of …

Investigation Of Urea Decomposition And Deposit Formation In Diesel Exhaust After-Treatment System, Anand Alembath

Doctoral Dissertations

“Urea-selective catalytic reduction (SCR) system has proved to be an effective solution to reduce NO_x emissions in commercial vehicle (CV) diesel engines. A significant challenge in urea injection is to comprehend its decomposition chemistry that leads to formation of undesired deposits in the exhaust system unit. Due to complex interaction of multi-phase fluid flow and transport processes, significant uncertainty is associated with the identification of interacting factors that control the deposit initiation and its growth. To meet the future ultra-low NO_x emissions and to deliver ammonia without deposit formation, there is an imminent need to develop the urea-SCR …

Mechanisms Of Pathogen Inactivation In Wastewater And Pharmaceutical Applications, Christa L. Meingast

Dissertations, Master's Theses and Master's Reports

Infectious diseases are a significant threat to public health. Though society enacts practices to prevent the spread of these dangerous diseases, challenges remain. Therefore, continual advancements in treatment and prevention are required. Wastewater treatment and viral clearance in pharmaceutical applications are two key health measures that prevent the spread of infections.

A low-cost, low-technology biosolids treatment process was developed to improve wastewater treatment by collecting key information on storage temperature, ammonia, volatile solids, moisture content, pH, and pathogen inactivation in biosolids over long-term storage at two wastewater treatment plants located in northern climates of the United States. Inactivation of pathogens …

Pelletization Of Cao Catalyst For Biodiesel Production Via Transesterification Of Palm Oil, Warisara Vornuch

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis investigates biodiesel production from palm oil by transesterification using extruded CaO catalysts. The preparation parameters of extruded CaO catalysts were investigated including 1) binder type including activated alumina, diatomite and kaolin, 2) calcination temperature at 700, 800 and 900°C, 3) mass ratio of CaO to the binder at 1: 1, 3: 1 and 6: 1. The Effect of catalyst shape of the extruded CaO and the addition of pore forming (polyacrylamide) on the catalytic activity of extruded CaO were also studied using transesterification using methanol to palm oil. The ratio of methanol to palm oil was fixed at …

The Deactivation Study Of Titanium Dioxide Catalyst In Thermochemical Processes Via Density Functional Theory, Chinanang Ngamlaor

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this study, the investigation of catalytic deactivation of TiO2 by coking was performed using DFT. The effect of the Hubbard U, which was varied as U equal 4 to 6 eV and Van der Waal corrections on electronic properties were also investigated. The effect of temperature in the range of 400-1000°C was also studied. This work aims to understand relatives of coke formation, oxygen vacancy, phase transformation. The increment of the Hubbard U values provide a more accurate quantitative cited by the energy gap from the experimental investigation, the appropriate U value of the A-TiO2 (101) is 4 eV, …

Deactivation Of Manganese Dioxide Electrocatalyst In Zinc-Air Batteries Studied Via Density Functional Theory, Puwit Buapin

Chulalongkorn University Theses and Dissertations (Chula ETD)

Manganese dioxide (MnO2) is the effective electrocatalysts used as a cathode for Zn-Air batteries (ZABs) accounted for the acceleration of the oxygen reduction reaction (ORR). There are various studies on the ORR activity of MnO2 rather than deactivation mechanisms. In this work, the deactivation mechanisms of α-MnO2 and β-MnO2 was investigated by density functional theory and computational hydrogen electrode. It was found that, the phase transformation from the α-MnO2 (211) to β-MnO2 (110) shows that the catalyst deactivation is due to the higher overpotential of β-MnO2 (110) making electrocatalyst efficiency low. For Ov surfaces, it illustrates that the performance is …