Engineering Commons^™

Process Optimization Of Bioactive Compound Extraction From Aloe Vera Leaf Skin Using Natural Deep Eutectic Solvents: An Integrated Computational-Experimental Approach, Sopita Chanmee

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study aimed to evaluate the efficiency of environmentally friendly natural eutectic solvents (NADESs) for the extraction of bioactive compounds from Aloe vera leaf skin (AVLS) in comparison with conventional solvents, namely water and 80% ethanol. The experiment used NADES based on choline chloride with four hydrogen bonding agents (HBDs), namely xylose, glycerol, propylene glycol and lactic acid. The results showed that ChCl:Xy gave the highest phenolic compounds content, while ChCl:La gave the highest anthraquinone content and antioxidant activity as tested by DPPH and FRAP. COSMO-RS and sigma profile analyses revealed the molecular interactions affecting the extraction efficiency, which showed …

Effect Of Graphene Nanoplatelets Addition During Electroless Plating Of Abs On The Quantity Of Pdcl2 Usage For Copper-Nickel-Chromium Coated Abs, Wantana Chuakamhod

Chulalongkorn University Theses and Dissertations (Chula ETD)

Acrylonitrile Butadiene Styrene (ABS) with chromium coating is widely used in applications requiring high strength, durability, and aesthetic appeal, such as automotive parts, electronics, appliances, sanitary fixtures, and decorative consumer goods. Before electroplating, nickel electroless plating is applied to ABS to create a conductive base, but this process traditionally relies on palladium (Pd), a costly material. This research explores reducing Pd usage by incorporating graphene into the plating bath, enabling a decrease in Pd concentration from the industrial standard of 16-25 ppm to just 6 ppm with the addition of 15 mg/L of graphene. The Ni-coated ABS achieved an electrical …

Simulation On Acid Gas Removal From Natural Gas Processing With Membrane And Absorption Process, Ratikorn Sornumpol

Chulalongkorn University Theses and Dissertations (Chula ETD)

The comparison using simulations of CO₂ removal from natural gas via membrane separation and monoethanolamine (MEA) absorption has been studied. The membrane model is applied with the single- and two-stage configurations over feed pressures 3,000–9,000 kPa, temperatures 10–59 °C, CO₂ concentrations 20–70 mol %, membrane areas 2,500–5,500 m², and flows 331,800–580,600 m³/h. At 10 °C feed temperature, CO₂ permeability is enhanced while CH₄ selectivity improves slightly, increasing CO₂ capture efficiency up to 74 % with only minor methane losses, though at the cost of higher refrigeration duty. The 10 °C operation also leads to stronger driving force across the membrane, …

Process Simulation And Techno-Economic Evaluation Of Free Lutein Production From Marigold Flowers, Yada Meayrin

Chulalongkorn University Theses and Dissertations (Chula ETD)

Lutein is a carotenoid widely recognized for its health benefits, including improved vision, cognitive function, and prevention of age-related diseases. This study presents a comprehensive techno-economic and environmental assessment of three crude free lutein production processes using marigold flowers (Tagetes erecta L.) at a processing capacity of 74 tons/year, modeled in Asplen Plus V.11. The evaluated processes include sequential extraction and de-esterification (SQP) using hexane (HEX) or liquefied dimethyl ether (LiqDME), and a one-step simultaneous extraction and de-esterification (SMP) using LiqDME. Among these, the SMP-DME process demonstrated the best performance, with a net present value (NPV) of 146.98 million US$, …

Arsenic Removal From Synthetic Produced Water Using Ionic Extractants And Vegetable Oils Via Hollow Fiber Supported Liquid Membrane, Natthawan Srinam

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis presents the separation of arsenic from water derived from synthetic petroleum production using a hollow fiber supported liquid membrane (HFSLM) system. The membrane system incorporates an ionic liquid extractant and a vegetable oil-based diluent. The study began with the selection of suitable extractants and diluents, followed by experimental design to determine optimal operating conditions using response surface methodology (RSM). Box-Behnken Design (BBD) and Central Composite Face-Centered Design (FCCD) were employed, and the data were analyzed through analysis of variance (ANOVA). Kinetic and thermodynamic studies revealed that the HFSLM system could achieve arsenic extraction and stripping efficiencies of up …

Aluminium-Doped And Carbon-Supported Zinc Oxide Ternary Composite Electrodes For Supercapacitor Applications, Abdulkadeem Sanni

Chulalongkorn University Theses and Dissertations (Chula ETD)

Developing high-performance supercapacitor electrodes requires materials with optimized electrical conductivity, surface area, morphology, energy density, and cyclability. Herein, we report a facile hydrothermal synthesis of carbon nanotubes (CNTs)-supported Al-doped ZnO@CuO composite. Structural characterization reveals that Al doping and CuO incorporation can transform ZnO nanoflakes into nanorod/nanoflower heterostructures. The electrochemical analysis of the quaternary composite in a mixed electrolyte containing 2 M KOH, 0.2 M KFC, and 0.2 M KI exhibits a specific capacitance of 1860 F/g at 1 mV/s. The fabricated asymmetric supercapacitor (ASC) yields an energy density of 36 Wh/kg, a power density of 3502.8 W/kg at 30 mA/g, …

Detection And Replacement Of States With Spikes And Noise By Long Short-Term Memory Models Or Neural Networks, Ittikorn Yutto

Chulalongkorn University Theses and Dissertations (Chula ETD)

Spike signals are impulsive disturbances with high amplitude occurring over a very short duration. They are typically caused by external factors such as temperature fluctuations, vibrations, or sensor inaccuracies, leading to erroneous measurements and potential degradation of control system performance. This study aims to develop a Long Short-Term Memory (LSTM) model for detecting and replacing spike signals in a second-order system. The model was trained and validated using datasets contaminated with spike signals of varying amplitudes. Experimental results demonstrated that the proposed model could suppress spike amplitudes by up to 99.79%, with a minimum reduction of 92.42% and an average …

Development Of Quaternized Poly(Vinyl Alcohol)/Chitosan/Two-Dimensional Molybdenum Disulfide Anion Exchange Membrane As A Separator For Electrochemical Processes, Nuttapon Suppanucroa

Chulalongkorn University Theses and Dissertations (Chula ETD)

In response to the global shift toward the expansion of large-scale energy storage systems (ESSs), secondary zinc-air batteries (ZABs) have attracted significant attention as promising candidates for next-generation batteries due to their high energy density, cost-effectiveness, and safety. However, their long-term practical application is hindered by several challenges associated with the membrane separator, including the formation of resistive zinc oxide layers and low hydroxide-ion conductivity. These limitations are attributed to poor ion-selectivity, which impedes electrochemical reactions and degrades battery performance. To address these issues, this study developed a series of innovative membrane separators featuring quaternary ammonium (QA)-functionalized polyvinyl alcohol (PVA), …

Hydrogen Production From Glycerol Using Sorption Enhanced Chemical Looping Steam Reforming With Multifunctional Pellet Catalyst, Talita Nimmas

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this study, the synthesis of a pellet-scale material for hydrogen (H₂) production from glycerol via the Sorption Enhanced Chemical Looping Steam Reforming (SE-CL-SGR) process was investigated. The research focuses on material synthesis, performance enhancement, and the economic and environmental advantages of the developed material. Among the synthesis methods compared, the Stepwise Calcination process demonstrated the best performance, producing structurally stable and mechanically robust pellets. The optimal CaO/support mass ratio for the Ni-supported material (15Ni(70Ca.30Support)) was found to achieve 90% v/v H₂ purity with a pre-breakthrough time of approximately 75 minutes. Rare-earth metal oxides (CeO₂, La₂O₃) addition also improved mechanical …

Lead-Free Perovskite/Metal Oxide Heterojunction Photocatalyst For Sustainable Toluene Oxidation, Zakarya Hazaea

Chulalongkorn University Theses and Dissertations (Chula ETD)

An important field of study is the ecologically benign synthesis of useful compounds such as benzaldehyde and benzyl alcohol from the organic contaminant toluene. Lead-free halide perovskites are excellent options for photocatalysis due to their exceptional photoelectric properties. Nonetheless, they have notable challenges, such as fast charge recombination and ineffective charge separation. In this work, we present a simple anti-solvent technique to create a heterojunction between lead-free halide perovskite Cs2AgBiBr6 (CABB) with Cu2O and Cu-Cu2O. This combination facilitates the photocatalytic activation of C(sp3)−H bonds, which in turn increases the oxidation of toluene. The Cu2O and Cu-Cu2O creating a Z-scheme heterojunction …

Electrostatic Sorting Of Lunar Regolith Simulants For Sustainable Resource Utilization: Modeling And Characterization Of Particle Size Distribution, Abdullah Al Moinee, Peter Bachle, Kyle Newport, William Schonberg, David Bayless, Jeffrey Smith, Daoru Han, Fateme Rezaei

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In pursuit of sustainable resource utilization on the Moon, this paper delves into modeling and characterization of particle size distribution (PSD) of lunar regolith simulants in an electrostatic system. a prototype electrostatic sieve was built and tested with four sample simulants mirroring properties of lunar mare and highland regolith. an alternating four-phase (90 degrees, 180 degrees, 270 degrees, 360 degrees) traveling square-wave was utilized for particle-directed transport to model the diverse trajectories of the particles. Numerically, we scrutinized how the distribution functions of the particles are manifested as the electrostatic field propagates, with a focus on three distinct particle ranges …

Photocatalytic Efficiency Of Graphene Quantum Dots Incorporated With Tio2 Under Visible Light For Degradation Of Organic Dye, Ilada Sanprasert

Chulalongkorn University Theses and Dissertations (Chula ETD)

The rapid industrialization and increased use of organic dyes for production in many industries have led to extensive environmental pollution concerns. At present, photocatalytic dye degradation is an outstanding environmentally friendly process for removal and treatment of organic dyes from water pollutants that cause no harm to the environment. In this research, we investigated the performance of different crystallographic structure of TiO2 (anatase, rutile, and mixed anatase/rutile P25 TiO2) under visible light irradiation. Furthermore, the TiO2 was modified using graphene quantum dots to evaluate their effect on photocatalytic efficiency. The characterization results of the GQDs/TiO2 photocatalyst composites demonstrated that GQDs …

Valorization Of Bourbon Distilling Waste Using Thermal Conversion Processes For Nutrient-Rich Food Products, Tosin Olayemi Olanrewaju

Theses and Dissertations--Biosystems and Agricultural Engineering

The Commonwealth of Kentucky accounts for over 95% of global bourbon production. A primary byproduct of bourbon production is stillage, which has a very high moisture content (91–94%) and high biochemical oxygen demand, making it challenging to manage. The recent expansion of the bourbon industry has heightened environmental concerns regarding the best methods to handle this byproduct. Dewatering and drying of stillage produce distillers' spent grains (DSG-B), which are rich in dietary fiber and protein and could serve as an excellent source of functional fiber in human nutrition.

This study examined the approach for dewatering, drying, inclusion of DSG-B as …

Characterization Of Antibody Repertoires Developed From Naive And Recall Responses, Nicholas C. Curtis

Dartmouth College Ph.D Dissertations

Adaptive immunity, comprised in part by the antibody repertoire, is the cornerstone of our ability to remain healthy amongst the plethora of pathogenic challenges we encounter daily. Despite the importance of understanding antibody repertoire development, much remains unknown about the composition and evolution of circulating antibodies in response to viral challenges. To better understand antibody repertoire development, we profiled the serum antibody repertoire using a combination of next-generation sequencing and serum antibody proteomics in the predominantly naïve response against SARS-CoV-2 spike and the recalled response to influenza hemagglutinin. The response to SARS-CoV-2 spike in four convalescent individuals was diverse (consisting …

Development Of Synthetically Accessible Glycolated Polythiophenes For High-Performance Organic Electrochemical Transistors, Bowen Ding, Vianna N. Le, Hang Yu, Guanchen Wu, Adam V. Marsh, Edgar Gutiérrez-Fernández, Nicolás Ramos, Martina Rimmele, Jaime Martín, Jenny Nelson, Alexandra F. Paterson, Martin Heeney

Chemical and Materials Engineering Faculty Publications

Four glycolated polythiophene-based organic mixed ionic-electronic conductors (OMIECs), PE2gTT, PE2gT, PT2gTT, and PT2gT are prepared by atom-efficient direct arylation polymerization, avoiding the need for toxic organometallic pre- cursors. PE2gT, PT2gTT, and PT2gT are operable in p-type accumulation mode organic electrochemical transistors (OECTs), with PT2gT displaying the best device performance with a μC* product figure-of-merit of 290 F cm−1 V−1 s−1 . A record volumetric capacitance among p-type glycolated polythiophene OMIECs of 313 F cm−3 is observed for PE2gT, ascribed to the high proportion- ality of polar components in its materials design. The good OECT performance of PE2gT with μC* = …

The Integrated Behavioral Model Of Mental Health Help Seeking (Ibm-Hs): A Health Services Utilization Theory Of Planned Behavior For Accessing Care, Joseph H. Hammer, David L. Vogel, Patrick R. Grzanka, Nayeon Kim, Brian T. Keum, Claire Adams, Sarah A. Wilson

Chemical and Materials Engineering Faculty Publications

This article introduces the integrated behavioral model of mental health help seeking (IBM-HS), a theoretical model for understanding the constructs (e.g., systemic, predisposing, and enabling factors; mental health literacy; illness perceptions; perceived need; stigma; shame; perceived benefits, motivation) that influence people’s decision making around seeking professional mental health care and their ultimate access to formal treatment. The IBM-HS is a help-seeking-specific adaptation of the empirically supported integrated behavioral model and integrative model, which are themselves evolutions of the theory of planned behavior and theory of reasoned action. The IBM-HS posits that help-seeking determinants (e.g., structural forces; cultural influences; past help-seeking …

Advanced Synthesis And Rational Design Of Support Structures For Nobel Metal Heterogeneous Catalysis: Towards Enhanced Activity And Continuous Processes, Brian R. Clark

Theses and Dissertations

The field of catalysis has a wide-ranging impact. Our group has identified the constant need for improved catalytic activity in high-impact applications such as hydrosilylation and cross-coupling reactions. For these reactions, precious metal catalysts often exhibit markedly better performance than their counterparts, but they can be a significant process cost that decreases overall economic efficiencies. To address this challenge, we explored support structures that can enhance catalytic activity at low metal loadings and improve precious metal recovery through simple filtration. We found that a platinum on graphene nanoplatelet catalyst (PtGNP) synthesized via strong electrostatic adsorption with microwave irradiation (SEA-MW) exhibits …

Monitoring Aerosols With Time Resolution With A Rotating Drum Sampler Using La-Icpms For Elemental Analysis, John V. Piorkowski

Honors Theses

This thesis presents a comprehensive study on the characterization and application of a rotating drum sampler for air quality monitoring, with a focus on aerosol composition analysis using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS). The study aimed to determine (1) the cut-off points of the drum sampler to better understand its performance characteristics and (2) to investigate indoor air quality, specifically within makerspaces on Bucknell University’s campus. The research highlighted the novelty of applying LA-ICPMS for time-resolved aerosol composition analysis, demonstrating the potential for low-cost pollution concentration studies. The characterization experiments did not yield expected results, but the …

Experimental Evaluation Of Mesh Size In Physically Crosslinked Polymer Gels Using Dynamic Light Scattering, Duncan M. Hill

Honors Theses

Block copolymer gels are under consideration as drug delivery patches. Controlling and modeling the transport inside the gel is an important contribution to the successful delivery of pharmaceuticals. The diffusive transport of a solute – such as a therapeutic compound – within the gel can be described by the mesh size of the gel, which is defined as the distance between polymer chains. Existing experimental evaluations of mesh size do not work for block copolymer gels due to differences in the fundamental gel structure. As such, an experimental method of measuring mesh size of block copolymer gels using dynamic light …

Molecular Dynamics Investigation Of Fluorine-Free Electrolytes For Sodium-Ion Batteries, Phitchapa Ausamanwet Zijdemans

Chulalongkorn University Theses and Dissertations (Chula ETD)

Sodium-ion batteries (SIBs) are a promising alternative to lithium-ion batteries due to the abundance and low cost of sodium. However, conventional SIB electrolytes often rely on fluorine-based salts, contributing to the formation of persistent and environmentally harmful per- and polyfluoroalkyl substances (PFAs). This study employs molecular dynamics (MD) simulations to investigates the properties of fluorine-free electrolytes for SIBs, focusing on the solvation structure and dynamics of sodium ions (Na+) in bulk electrolytes and at the inner solid electrolyte interphase (SEI) for SIBs. Sodium perchlorate (NaClO4) at a concentration of 1 M was examined in glyme solvents with varying chain lengths, …

Ltspice Modeling For Gan-Git Hemt Including Cryogenic Temperature, Md Maksudul Hossain, Yuqi Wei, H. Alan Mantooth

Electrical Engineering Faculty Publications and Presentations

Highly efficient electrically driven avionics have led to a renewed interest in cryogenic propulsion systems with the goal of reducing carbon emission footprint. Although cryogenic converters promise better efficiency and improved power density, the successful design is incumbent upon the appropriate switching device selection and simulation-based analyses prior to initial prototyping. In this work, a datasheet-driven compact model for a gallium nitride (GaN) Gate Injection Transistor (GIT) has been proposed and implemented in LTspice, a versatile, high performance, and free circuit simulator in order to investigate the merit of the chosen device in a power electronic system.

Dough Rheology And Its Influence On Sheeting Behavior, Najat Albarakati

Graduate Theses, Dissertations, and Problem Reports (ETD)

Dough is the starting material for a large number of baked products, including cookies, crackers and bread. In commercial food processing operations, it is desired to obtain the same product and with the same dimensions in a reproducible manner in order to minimize waste. In the case of dough, the flour used, and the nature and amount of ingredients employed depend on the specific product and the market served. This research was aimed at relating cracker dough rheology to sheeting behavior between two counter-rotating rollers. The sheet that is formed is used to punch out the crackers that are then …

Development Of Dynamic Modeling And Estimation Techniques For Condition Monitoring Of Advanced Energy Systems, Vivek Saini

Graduate Theses, Dissertations, and Problem Reports (ETD)

The integration of renewable energy sources into the electric grid requires the current fleet of fossil-fired power plants to operate more flexibly, leading to frequent load changes that stress critical high temperature boiler components that were primarily designed for base load operations. The more complex operating scenarios can modify component damage, compromising reliability and increasing operational costs. To ensure efficient plant operations, adaptive condition monitoring tools generalizable for different plant configurations are essential for recognizing the impacts of load-following, improving safety, and preventing outages. This dissertation work is primarily focused on the development of advanced modeling and estimation techniques frameworks …

Polylactic Acid (Pla) Containing Talc Microparticles And Amorphous Polyhydroxyalkanoates (Aphas) For Improved Barrier And Mechanical Properties In Food Packaging, Mohammed Alfaifi

Graduate Theses, Dissertations, and Problem Reports (ETD)

Polylactic acid (PLA) is a biobased and compostable polymer that is increasingly being used as an alternative to petroleum-based, non-biodegradable polymers for single-use food packaging due to its environmental benefits. It is also commercially available in large quantities, and it can be processed like polyethylene. However, it has a higher water-vapor permeability (WVP) as compared to polyolefins and polyethylene terephthalate that are the incumbent materials. This results in a competitive disadvantage in employing PLA for packaging baked goods since the shelf life of the food is likely to be reduced. In the past, barrier properties of PLA were improved by …

Strategies For Process Systems Mapping And Control Based On Operability Analysis, Victor Manuel Cunha Alves

Graduate Theses, Dissertations, and Problem Reports (ETD)

This dissertation aims to develop strategies for process systems engineering (PSE) mapping using models, emerging tools and algorithms motivated by process operability analysis research. Such strategies will be employed to ensure simultaneous design and control of large-scale industrial systems. The emerging tools and techniques in this research include supervised machine learning-based (ML-based) operability mapping, automatic differentiation (AD) for implicit mapping, and the development of a systematic mapping approach for control structure selection using operability analysis. Thus far, the developed operability algorithms either recur to nonlinear programming (NLP) solutions which are computationally expensive or to linearizing the underlying modeling task at …

Investigation Of Synergistic Effect Between Polystyrene And Polyethylene Under Conventional Thermal Heating And Microwave Heating, Thang Luong

Graduate Theses, Dissertations, and Problem Reports (ETD)

Single-use plastics (Low Density Polyethylene, LDPE; Polystyrene, PS; Polypropylene, PP) are increasingly used in the modern world, with their usage growing every year. An effective method to manage the resulting waste is urgently needed, as landfilling and incineration have proven harmful to the environment in the long term. Mechanical recycling may not maintain the desirable characteristics of the single-use plastics through several cycles. Pyrolysis emerges as a promising approach to address plastic waste. Given that single-use plastic waste often comes in a mixture, combining plastic in the feedstock is a viable solution to effectively convert these polymers altogether to gain …

Electron-Induced Chemical Transformations In Polymer Films: Understanding The Role Of Electrons In Euv Lithography, Maximillian Mueller

Master's Theses

The next generation of computer processors, memory, and nano-scale technologies all rely on our ability to create patterns at the nanometer scale reliably. Extreme ultraviolet (EUV) lithography can create sub-10 nm features by exposing photoresist materials, typically polymers or organic networks, to 13.5 nm, 92 eV light. At these energies, absorption of photons by the photoresist leads to the emission of a primary electron around 80 eV which inelastically scatters throughout the material, initiating chemistry and creating secondary electrons. The resulting cascade of electrons and chemical reactions remains poorly understood for most photoresist materials systems. This work aims to characterize …

Sustainable Materials For Environment − Multifunctional Material Made From Dead Leaves And Nanostructured Materials For Antibiotic Degradation, Siyuan Fang

Dissertations, Master's Theses and Master's Reports

As environmental pollution from industrial processes and human activities continues to rise, finding efficient approaches to recycle waste materials and degrade persistent contaminants becomes increasingly critical. Dead leaves, an abundant but underutilized biomass, present an opportunity for creating value-added materials if their biocomponents can be preserved and transformed. Simultaneously, antibiotics such as tetracycline are widely found in water bodies but pose serious ecological and health risks, necessitating effective degradation methods. This dissertation addresses these challenges by leveraging natural and nanostructured materials to develop multifunctional products and advanced photocatalytic processes.

Chapter 3 of this dissertation addresses the challenge of converting waste …

Preliminary Remote Identification Of Unstable Zone On Large-Scale Waste Dump At Mae Moh Mine Using Insar Technique, Chitra Buth

Chulalongkorn University Theses and Dissertations (Chula ETD)

Mae Moh Mine is one of the largest lignite mine in Southeast Asia, operated by the Electricity Generating Authority of Thailand (EGAT). It is located in the northern part of Thailand, in Mae Moh district, Lampang province. In March 2018, a significant sliding incidence occurred at a waste dump site with sliding area of 1.56 km2 approximately, highlighting the pressing issue of instability within this large-scale waste dump area. This study aims to address this concern in the future and demonstrate an innovative method for investigating the failure by employing Interferometric Synthetic Aperture Radar (InSAR) technology. The methodology involves the …

Solvent-Free Manufacturing Of Lithium-Ion Battery Electrodes Via Cold Plasma, Zhiming Liang, Tianyi Li, Holden Chi, Joseph Ziegelbauer, Kai Sun, Ming Wang, Wei Zhang, Tuo Liu, Yang-Tse Cheng, Zonghai Chen, Xiaohong Gayden, Chunmei Ban

Chemical and Materials Engineering Faculty Publications

Slurry casting has been used to fabricate lithium-ion battery electrodes for decades, which involves toxic and expensive organic solvents followed by high-cost vacuum drying and electrode calendering. This work presents a new manufacturing method using a nonthermal plasma to create inter- particle binding without using any polymeric binding materials, enabling solvent-free manufacturing electrodes with any electrochemistry of choice. The cold-plasma-coating technique enables fabricating electrodes with thickness (>200 lm), high mass loading (>30 mg cm^-2), high peel strength, and the ability to print lithium-ion batteries in an arbitrary geometry. This crosscutting, chemistry agnostic, platform technology would increase energy density, …