Modification Of Γ-Al2o3-Supported Ni Catalysts By Wo3 Addition For Co2 Reforming Of Methane, Visansya Malaimat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Carbon dioxide reforming or dry reforming of methane (DRM) is not a mature process in the industry despite the economic benefits. The main obstacle preventing the commercialization of these reactions is carbon deposition caused by side reactions. This work investigates the improvement of the Ni/ γ-Al2O3 catalyst's stability and resistance to carbon deposition by WO3 addition. The effect of WO3 loadings amount, varying among 0.5 -13 wt% was investigated. The catalyst was prepared by the incipient wetness impregnation method using the feed gas mixture at a CH4:CO2 ratio of 1:1 at 700 oC for 3 hours. The addition of WO3 …

Effect Of The Second Promoter On Pt/Wox/Al2o3 Catalyst Deactivation For The Selective Glycerol Hydrogenolysis To 1,3-Propanediol, Sittichai Damruang

Chulalongkorn University Theses and Dissertations (Chula ETD)

The selective glycerol hydrogenolysis is a good promising reaction to produce 1,3-propanediol. The Pt-WOx bifunctional catalyst is extensively interested, but the catalyst deactivation via sintering, metal leaching, and coking can predominantly occur in the aqueous phase reaction. In this research, the effect of reaction temperature and pressure was investigated. The role of the second promoter on Pt/WOx/Al2O3 catalyst was studied, including Cu, Fe, Rh, Mn, Re, Ru, Ir, Sn, B, and P, to improve synergy between Pt, WOx, and Al2O3. The physicochemical properties and the interaction of Pt with Al2O3 were investigated as well. The second promoter improves the catalytic …

Enhancement Of Catalytic Stability Of Fe2o3/Sio2 Catalyst Prepared By The Sol-Gel Method For Selective Oxidation Of H2s To Sulfur., Athitaya Promtongkaew

Chulalongkorn University Theses and Dissertations (Chula ETD)

The H2S selective oxidation is the most attractive process for converting H2S to elemental sulfur, but the industrial problem of this process is the catalytic stability. In this work, two different synthesis methods (sol-gel (SG) compared with incipient wetness impregnation (IWI) as a widely used method) were used to synthesize iron oxide supported on silica catalysts (Fe2O3/SiO2) with metal loadings ranging from 0.5 to 10 %wt. The catalysts were tested for the selective oxidation of H2S, changing the operating conditions like temperature (170 – 250 °C), O2/H2S (0.5 – 2.5) and water content (0 – 50 %). A detailed characterization …

Lignin Micro-Nano Particles From Organosolv Lignin Of Domestically Available Oil Palm Empty Fruit Bunch, Orawan Thasanabenjakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Lignin nanoparticles have potential value in biomedical and environmental applications. Utilizing oil palm empty fruit bunches (OPEFB) for lignin nanoparticles production can improve the economics of oil palm. In this study, lignin was extracted from OPEFB by acid-catalyzed organosolv method, using either glycerol/glycerol carbonate or ethanol/water as the solvent. The FT-IR spectra of the lignin particles extracted by glycerol/glycerol carbonate and ethanol/water suggest that the ethanol/water system was able to remove more functional groups from the OPEFB than glycerol/glycerol carbonate. Without the homogenization, the organosolv lignin particle sizes extracted by glycerol/glycerol carbonate and ethanol/water were broadly distributed, ranging between 8-154 …

Carbon Dioxide Reforming Of Biogas On Hydrotalcite-Derived Ni-Mg-Al Catalyst Pellets: Effects Of Ce And La Promotors, Aekburut Yuangthong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Carbon dioxide (CO2) is the major component in biogas that leads to the lower heating value and biogas grade. Carbon dioxide reforming of biogas is an alternative way to utilized CO2 and upgrading biogas to hydrogen and carbon monoxide, syngas, which can be utilized as precursor for various chemical production. The Ni-based hydrotalcite-derived catalyst has become of interest to provide the advantages such as high surface area, high thermal stability and well-dispersed metal particles. In this study, NiMgAl catalysts are synthesized and pelletized for the carbon dioxide reforming of biogas. To enhance the activity and stability of the catalysts, Ce …

Guerbet Reaction Of Ethanol To Butanol Over Mgai Mixed Oxide Catalysts, Patchaporn Seekhiaw

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aims to investigate the Guerbet reaction of ethanol to butanol over MgAl mixed oxide catalysts. The MgAlO catalyst was obtained from calcination of MgAl-LDH. This study has been divided into three sections. In the first section, the effect of ethanol flow rate and nitrogen flow rate on Guerbet reaction of ethanol to butanol were examined. It was found that the optimal condition of ethanol flow rate and nitrogen flow rate for Guerbet reaction were at the weight hour space velocity (WHSV) of 3.1 h-1 and 900 mL/h of nitrogen flow rate, which gave 3.94% of butanol yield. Therefore, …

Therapeutic Injectable Iron-Chelating Hydrogels, Debbie Campbell-Rance

Theses and Dissertations

ABSTRACT

Therapeutic Injectable Iron-Chelating Hydrogels for Improved Central Nervous System Regeneration

By

Debbie S. Campbell-Rance

A dissertation submitted in partial fulfillment of the requirements of the degree of Doctor of Philosophy at Virginia Commonwealth University 2021.

Director: Xuejun Wen, M.D., Ph.D., AIMBE Fellow, Alice T. and William H. Goodwin Jr. Endowed Chair Professor in Regenerative Medicine, Institute for Engineering and Medicine, Department of Chemical and Life Science Engineering

Severe traumatic brain and spinal cord injuries are major global public health and socioeconomic problems in terms of mortality and morbidity. Currently there are two main lines of treatment under development for …

Understanding Structure/Process-Property Relationships To Optimize Development Lifecycle In Yttria-Stabilized Zirconia Aerogels For Thermal Management, Rebecca C. Walker

Theses and Dissertations

Aerogels are mesoporous materials with unique properties, including high specific surface area, high porosity, low thermal conductivity, and low density, increasing these materials’ effectiveness in applications such as catalyst supports, sorption media, and electrodes in solid oxide fuel cells. Zirconia (ZrO₂) aerogels have special interest for high-temperature applications due to the high melting point of ZrO₂ (2715°C) and stability between 600°C and 1000°C, where other aerogel systems often begin to sinter and densify. These properties and unique pore structure make zirconia aerogels advantageous as thermal management systems, especially in aeronautics and aerospace applications. However, to be effective …

Spontaneous Symmetry Breaking And Linear Electrooptic Response In The Achiral Ferronematic Compound, Neelam Yadav, Yuri Panarin, Wanhe Jiang, Georg H. Mehl, J.K. Vij

Articles

A compound with the constituent non-chiral molecules, DIO, known to exhibit three nematic subphases namely N, Nx and NF, is studied by polarizing microscopy as function of the alignment layers on one of the substrates, no alignment on any of the substrates, alignment layer on both substrates with parallel and antiparallel rubbing, different cell spacings. The cell with one alignment layer is also studied by electro-optics. N is found to be a conventional nematic phase, but it shows two additional unusual features: chiral domains of opposite chirality and the linear EO response to the applied signal under certain experimental conditions. …

Data Driven Bayesian Network To Predict Critical Alarm, Joseph Mietkiewicz, Anders Madsen

Articles

Modern industrial plants rely on alarm systems to ensure their safe and effective functioning. Alarms give the operator knowledge about the current state of the industrial plants. Trip alarms indicating a trip event indicate the shutdown of systems. Trip events in power plants can be costly and critical for the running of the operation.This paper demonstrates how trips events based on an alarm log from an offshore gas production can be reliably predicted using a Bayesian network. If a trip event is reliably predicted and the main cause of it is identified, it will allow the operator to prevent it. …

Advanced Process Modeling And Optimization Of Amine-Based Carbon Capture Process, Paul Jide Terhemba Akula

Graduate Theses, Dissertations, and Problem Reports (ETD)

With the rise of carbondioxide (CO2) concentration in the atmosphere to more than 400 parts per million (ppm), research efforts have been focused on achieving net-zero carbon emission technologies. Post-combustion CO2 capture (PCC) is a key strategy in reducing CO2 emissions. Amine-based CO2 capture is the baseline technology for retrofitting existing power stations. However, the integration of amine-based PCC technology with power plants to reduce greenhouse gas emissions incurs a high energy penalty, decreasing a powerplant’s efficiency by about 23 percentage points. Understanding the capture plant dynamics plays an important role in its technical and economic performance. Rigorous models are …

Immunomodulatory Functions Of Human Mesenchymal Stromal Cells Are Enhanced When Cultured On Hep/Col Multilayers Supplemented With Interferon-Gamma, Mahsa Letter-Mahsa Haseli, David A. Castilla-Casadiego, Luis Carlos Pinzon-Herrera, Alexander Hillsley, Katherine A. Miranda-Munoz, Srikanth Sivaraman, Adrianne M. Rosales, Raj R. Rao, Jorge Almodovar

Chemical Engineering Faculty Publications and Presentations

Human mesenchymal stromal cells (hMSCs) are multipotent cells that have been proposed for cell therapies due to their immunosuppressive capacity that can be enhanced in the presence of interferon-gamma (IFN-γ). In this study, multilayers of heparin (HEP) and collagen (COL) (HEP/COL) were used as a bioactive surface to enhance the immunomodulatory activity of hMSCs using soluble IFN-γ. Multilayers were formed, via layer-by-layer assembly, varying the final layer between COL and HEP and supplemented with IFN-γ in the culture medium. We evaluated the viability, adhesion, real-time growth, differentiation, and immunomodulatory activity of hMSCs on (HEP/COL) multilayers. HMSCs viability, adhesion, and growth …

Machine Learning Based Real-Time Quantification Of Production From Individual Clusters In Shale Wells, Ayodeji Luke Aboaba

Graduate Theses, Dissertations, and Problem Reports (ETD)

Over the last two decades, there has been advances in downhole monitoring in oil and gas wells with the use of Fiber-Optic sensing technology such as the Distributed Temperature Sensing (DTS). Unlike a conventional production log that provides only snapshots of the well performance, DTS provides continuous temperature measurements along the entire wellbore.

Whether by fluid extraction or injection, oil and gas production changes reservoir conditions, and continuous monitoring of downhole conditions is highly desirable. This research study presents a tool for real-time quantification of production from individual perforation clusters in a multi-stage shale well using Artificial Intelligence and Machine …

Quantitative Analysis Of Rate Transient Analysis In Unconventional Shale Gas Reserviors, Gabriel Quintero

Graduate Theses, Dissertations, and Problem Reports (ETD)

Rate Transient Analysis is a quick reservoir modeling solution that has been used throughout the oil and gas industry over its continuous development and has provided breakthroughs for modeling conventional plays for decades. As the Marcellus Shale play continues to be a massive producer of Natural Gas in the world, operators look to find economical yet fairly accurate solutions to develop accurate reservoir models of their wells given the complex nature of unconventional reservoirs. Due to extremely low permeability and heterogeneity along with its complex fracture networks, it becomes an extremely difficult problem to model and predict the fluid flow …

Ethane Dehydrogenation For Light Olefins Production Over Stable Catalyst, Xiaoyan Wang

Graduate Theses, Dissertations, and Problem Reports (ETD)

Accompanied by the development of modern industry, the demand for light olefins (e.g., ethylene, propylene, butene, butadiene) increases year by year. Light olefins are important intermediates in producing polymers (Polyethylene, Polypropylene, etc.) and rubber (Styrene Butadiene Rubber, Polybutadiene rubber, etc.). The primary process for the production of light olefins is steam cracking of petroleum liquids (naphtha and distillate fuel oil). It is an energy-intensive process, requiring high temperature (750-850℃) and pressure (1.0-4.5 MPa). Meanwhile, due to undesired side reactions, this process has lowered the efficiency of light olefins production and suffers from severe coking issues. Furthermore, as petroleum liquids become …

A Workflow For Unconventional Reservoirs Optimization Using Supervised Machine Learning In Conjunction With Orthorhombic Elasticity Modeling, Aymen Ab Ali Alhemdi

Graduate Theses, Dissertations, and Problem Reports (ETD)

Due to the anisotropy and heterogeneous nature of unconventional reservoirs like shale, a comprehensive parametric study to optimize hydraulic fracture treatment for such reservoirs is a tough challenge, especially when natural fractures are present. Most of the current frac simulators do not consider the anisotropy of rock elasticity in the shales. Besides, using the fracture simulation linked with reservoir simulation for the parametric study to understand the impact of multiple different design parameters on fracture propagation and production is time expensive and low efficient. The study proposes a workflow including a new orthorhombic (OB) rock algorithm to interpret geomechanical properties …

Microwave-Assisted Carbon Nanotube Growth From Methane On Surface Catalyst Exsolving Perovskite Oxide, Angela M. Deibel

Graduate Theses, Dissertations, and Problem Reports (ETD)

The novel method of using a perovskite exsolution catalyst, strontium titanium nickel oxide (STNO), proved capable of simultaneously producing carbon nanotubes (CNTs) and CO_x-free hydrogen during methane decomposition under microwave irradiation. An optimization of common perovskite materials was conducted for microwave-responsiveness with the results reported in this study. Out of the materials screened, strontium titanium nickel oxide (STNO) was the best candidate to achieve an acceptable methane conversion rate as well as a decent responsiveness to microwave. STNO was further optimized through Ni content, reduction dwell time, and reduction temperature to produce the best methane conversion and CNT …

Nano-, Encapsulated Manganese Oxide (Nemo) Particles For Mri Enhancement In Microfluidic Tumor Models, Kasey Alexis Freshwater

Graduate Theses, Dissertations, and Problem Reports (ETD)

Breast cancer is among the deadliest cancers in women, with approximately 2.3 million new cases and 685,000 deaths reported globally in 2020 alone. Magnetic Resonance Imaging (MRI) is commonly used to diagnose, stage, and develop treatment plans for patients predisposed to breast cancer. However, current MRI-based screening of breast cancer has high false-positive rates up to 25%, leading to unnecessary invasive follow-up screening and testing. The gold-standard intravenous gadolinium (Gd)-based contrast agents (GBCAs) account for false-positive rates because they are always “ON”, providing a constant MRI signal that highlights both benign and malignant tumors. The work detailed in this thesis …

Reinforcement Learning For Process Control: Applications To Energy Systems, Elijah Ballard Hedrick

Graduate Theses, Dissertations, and Problem Reports (ETD)

Reinforcement learning (RL) is a machine learning method that has recently seen significant research activity owing to its successes in the areas of robotics and gameplaying (Silver et al., 2017). However, significant challenges exist in the extension of these control methods to process control problems, where state and input signals are nearly always continuous and more stringent performance guarantees are required. The goal of this work is to explore ways that modern RL algorithms can be adapted to handle process control problems; avenues for this work include using RL with existing controllers such as model predictive control (MPC) and adapting …

Optimum Geological Storage Depths For Structural H2 Geo-Storage, Stefan Iglauer

Research outputs 2022 to 2026

H₂ geo-storage has been suggested as a key technology with which large quantities of H₂ can be stored and withdrawn again rapidly. One option which is currently explored is H₂ storage in sedimentary geologic formations which are geographically widespread and potentially provide large storage space. The mechanism which keeps the buoyant H₂ in the subsurface is structural trapping where a caprock prevents the H₂ from rising by capillary forces. It is therefore important to assess how much H₂ can be stored via structural trapping under given geo-thermal conditions. This structural trapping capacity is thus …