Engineering Commons^™

Hot-Fire Testing Of An Af-M315e 1-Newton Thruster, Alex Mcgee

Honors Theses

AF-M315E is a green monopropellant currently being investigated for use as a potential replacement for hydrazine in low-thrust spacecraft propulsion applications. To support devel- opment e↵orts, a series of hot-fire tests were conducted to assess the performance of AF-M315E in a 1N thruster. Preliminary design and analysis shows an increase in performance versus a comparable hydrazine system. Testing was conducted with a 1N TZM (titanium, zinc, and molybdenum alloy) thruster in late July 2016 in collaboration with the Spacecraft Propulsion Systems o ce (ER23) at Marshall Space Flight Center (MSFC). Testing focused on character- izing the transient behavior of the …

Cellulose Nanocrystal Stabilized Pickering Emulsions, Sangeet Adhikari

Honors Theses

The use of Pickering Emulsions in place of conventional surfactants has opened new doors in fields like pharmacy, cosmetology, and oil and gas industry. Pickering emulsions using Cellulose Nanocrystals (CNCs) are generally stable to heating in a wide range of temperatures and show great stability against salt and pH changes. The management of water resources in the United States has been a challenge. The injection of water in aging oil fields and unconventional tight-gas, shale-gas, and coal bed-fields often generate substantial amounts contaminated wastewater. This research project is expected to help future efforts in promoting oil biodegradation in emulsified mixtures. …

Utilizing The Zebrafish Model To Determine Anti-Epileptic Properties Of Mistletoe And Cannabis, Collin Dietrich

Honors Theses

Epilepsy affects around 50 million people in the world, therefore improving treatment efficacy and safety for epileptics is imperative. In this study we sought to screen the effectiveness and safety of cannabis constituents (delta-9-tetrahydrocannabinol and cannabidiol) and Tapinanthus globiferus extracts in treating epilepsy. We used a zebrafish model wherein seizures were induced by treatment with pentylenetetrazol. Our results showed that Tapinanthus globiferus dose-dependently reduced seizure activity, and no toxicities were seen at the concentrations used. In contrast delta-9-tetrahydrocannabinol and cannabidiol did not significantly reduce seizure activity and some toxicities were seen at the higher concentrations tested. We conclude that extracts …

Determination And Validation Of High-Pressure Equilibrium Adsorption Isotherms Via A Volumetric System, Hind Jihad Kadhim Shabbani

Theses and Dissertations

Adsorption equilibrium isotherms for N2, CO2, and CH4 on zeolite 13X were investigated at three different temperatures (25.5, 50.5 and 75.5 ̊ C) and a pressure range of (0-6.89475) MPa for CH4 and N2 and in the range of (0-4.82633) MPa for CO2 using built in volumetric apparatus. The results were validated using with a volumetric system (ASAP) at the same temperatures and a pressure up to (160-110) KPa respectively. The experimental results were correlated using three process Langmuir (TPLM). The correlated isotherms were then used to calculate the isosteric heat of adsorption for the three gases on 13X. The …

Stilbenes: Therapeutic Interventions Targeting Amyloid Β Protein Aggregation In Alzheimer’S Disease, Yiying Wang

Theses and Dissertations

Alzheimer’s disease (AD) is the most common form of dementia and accounts for 60-80 % of all dementia cases. In the United States, AD is ranked as the 6th leading cause of death and it is the only one among the top 10 that cannot be prevented, treated or even slowed. All FDA approved drugs focus on attenuating the symptoms for a limited time by regulating neurotransmitters without any intervention with the underlying disease process. A major player in the initiation and development of this debilitating disorder is the misfolding and subsequent aggregating of amyloid-β (Aβ) peptide. This aggregation process …

Statistical Mechanics Of Lipid-Liquid Crystal Systems: From Fundamentals To Sensing Applications, Donya Ohadi Kabir Maghsudlu

Theses and Dissertations

Understanding the thermodynamics of small systems has a well-established history. The non-intuitive behavior of the intensive properties of small systems comprised of less than a few hundred particles has important implications in many areas of engineering and materials science. Nevertheless, many open questions about the thermophysical properties of systems not in the thermodynamic limit remain unanswered. In the first part of this work, we explore the consequences of the coupling of two small subsystems that together make up a larger isolated system through the use of statistical mechanics and molecular dynamics simulations of Lennard-Jones particles in two dimensions. The results …

Pollutant Formation In Oxy-Coal Combustion, Nujhat Choudhury

Theses and Dissertations

With the increasing levels of carbon dioxide (CO2) in the atmosphere, researchers are driven to seek cleaner combustion techniques to burn coal for power generation. Oxy-coal combustion is a promising technique to cut down CO2 emissions. This technology requires the introduction of a pure oxygen (O2) stream and a recycled flue gas stream into the boiler instead of air. Flue gas stream generated from the system will be low in volume and highly concentrated in CO2. Thus, the capture and sequestration process will be facilitated. But, one of the concerns of adopting this technology is the altered chemistry of pollutants …

Co2 Capture From Flue Gas By A Psa Process Using A Novel Structured Adsorbent, Nima Mohammadi

Theses and Dissertations

First adsorption equilibrium isotherms for N2, O2, Ar and CO2 on zeolite 13X were measured at three temperatures (25, 50, 75 °C) and pressures up to 110 kPa with a volumetric method and validated by also measuring the same isotherms with a gravimetric system.

Then a comprehensive 2-D mathematical model was developed to study the fundamentals of adsorption processes in parallel channel structured adsorbents. The results clearly indicated that under studied circumstances the plug flow condition can be assumed and therefore the system is not subject to premature breakthrough.

The pressure drop of corrugated structured adsorbents with narrow triangular channels …

Supercritical Carbon Dioxide Treatment Of Natural Biomaterials For Tissue Engineering Applications, Dominic M. Casali

Theses and Dissertations

The number of people requiring an organ transplant in the United States has increased considerably over the past 25 years, but the number of organ donations has stagnated; over 8,000 people now die annually while awaiting a transplant or become too sick to receive one. Tissue engineering (TE), the design and production of artificial tissues and organs in vitro, has been proposed to alleviate this problem. Though synthetic polymers offer tunable mechanical and biochemical properties, natural biomaterials have recently garnered attention in TE for their high degree of biocompatibility and ability to direct cell proliferation and constructive tissue remodeling. Yet …

Rational Synthesis Of Catalysts For Biomass Conversion, Qiuli Liu

Theses and Dissertations

With climate change due to global warming, the production of hydrocarbon fuels and chemicals from renewable biomass resource has become more pressing in recent decades. The biggest challenge in biomass conversion is to develop active, selective and stable catalysts for particular applications. The objective of this research is to optimize catalytic performance for hydrodeoxygenation (HDO) and hydrogenation reactions by enhancing the stability of the support, tuning metal particle size, and controlling surface composition.

The high content of water in bio-oil and the aqueous environment of the upgrading process requires a hydrothermally stable catalyst. The hydrothermal stability has been effectively improved …

Synthesis And Characterization Of Cross-Linked Polyimide Film Using Tolylene Diisocyanate, Sirichai Reeyakad

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cross-linked polyimide films were synthesized by the reaction between diisocyanate groups and hydroxyl functional groups in polyimide structure, which was confirmed by IR. During the thermal treatment of the cross-linked polyimide, the thermal labile component (CO₂) in the urethane segments was decomposed which might generate pores in the film. The presence of the pores was confirmed from the dielectric constant of the film. The dielectric constant of the films decreased with the increase of TDI loading. By comparing the properties of the films, the PI50-C1.0 exhibited optimum mechanical and good dielectric properties. The cross-linked structure was also confirmed by DMA. …

Catalytic Ethanol Dehydration To Diethyl Ether Over Palladium-Modified Phosphorus Gamma Alumina Catalysts, Chakkrit Khaochartchai

Chulalongkorn University Theses and Dissertations (Chula ETD)

The gamma alumina (γ-Al2O3) catalyst was modified with phosphorous (P) by acid activation technique and palladium (Pd) by the incipient wetness impregnation technique. The obtained catalysts were characterized with various techniques including X-ray diffraction (XRD), inductively coupled plasma (ICP), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX), N2 physisorption, ammonia temperature-programmed desorption (NH3-TPD), and thermogravimetric analysis (TGA). In addition, these modified catalysts were tested in ethanol dehydration reaction in a fixed-bed microreactor to determine ethanol conversion and product yield at the atmospheric pressure with temperatures ranging from 200-400oC. From the results, the phosphorous modification diminished the amount of …

Co2 Methanation Over Nial2o4 Spinel - Based Catalysts, Chanya Thamma

Chulalongkorn University Theses and Dissertations (Chula ETD)

In the present work, a series of NiO/NiAl2O4 catalysts were prepared by co-precipitation method with molar ratio of Ni/Al equal 1/2 at different precipitation temperatures (30 and 80oC) and calcination temperatures (500, 700, 900, and 1200oC). The catalyst properties were characterized by using N2 physisorption, X-ray diffraction, H2 - TPR, SEM, and TEM. The NiO/NiAl2O4 precipitated at 80oC and calcined at 900oC showed the best activity in CO2 methanation at 350oC with conversion 92% and 100% methane selectivity without CO formation. The optimal of NiO and NiAl2O4 composition at 24.7% and 75.3%wt could provide a stabilizing effect preventing the metal …

Dehydration And Oxidative Dehydrogenation Of Ethanol Over Sba-15 Based Catalysts Prepared By Sol-Gel And Hydrothermal Methods, Chaowat Autthanit

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this present study, characteristics and catalytic properties of zirconium (Zr) and bimetal (Zr and La) containing in SBA-15 catalysts and different VOx/SBA-15 catalysts were determined and well related. The study was divided into three parts. Regarding to the first part, zirconium (Zr) and bimetal (Zr and La) containing in SBA-15 synthesized by sol-gel and hydrothermal methods were compared. The results showed that the incorporation of Zr and bimetal (Zr and La) had an effect on the textural properties of both synthesized SBA-15 catalysts. Surface acidity in the SBA-15 suggests new active sites, especially Brønsted acid type. In the second …

Functionalization Of Carbon Nanohorns And Their Catalysis Applications, Chompoopitch Termvidchakorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Carbon nanohorns (CNHs) synthesized by gas-injected arc-in-water method were functionalized in this study. Metal (Ni, Cu, Fe, Pd, and Pt) and their alloy (NiCu, NiFe, NiPd, and NiPt) hybridized with CNHs were successfully produced. In addition, thermal and acid treatment was applied on the hybridized materials. Effect of metal loading and functionalizing conditions on characteristics of CNHs and functionalized CNHs was examined based on transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), N2 sorption, Raman spectroscopy, Fourier transform infrared (FT-IR) spectrometer, temperature programmed desorption of ammonia (NH3-TPD) analysis. The functionalized CNHs were applied as a catalyst in …

Conversion Of Glucose To Levulinic Acid By Fe/Carbon Nanoparticle Catalyst Synthesized From Lubricant Oil And Ferrocene, Jirarat Kaewngam

Chulalongkorn University Theses and Dissertations (Chula ETD)

Currently, production of levulinic acid which is one of promising chemical substances derived from biomass has been intensively investigated. Different catalyst types have been employed to produce levulinic acid from glucose including zeolite, metal phosphate and alumina. However, carbon based catalysts with high thermal stability, ease of surface functionalization and acid-base resistance were not widely studied. In this thesis, carbon nanoparticles synthesized from lubricant oil and ferrocene via co-pyrolysis was fully studied for glucose conversion to levulinic acid. The effect of carbon nanoparticles acid treatment was mainly investigated in terms of glucose conversion and levulinic acid yield. Pristine magnetic carbon …

Effects Of Carbon Fiber And Glass Fiber On Shape Memory Polymers Based On Benzoxazine-Epoxy Binary Systems, Jutamart Plylaharn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Recovery stress is an important parameter of shape memory polymers. Generally, recovery stress in SMPs can be enhanced by using fiber reinforced composites with suitable reinforcing agents such as carbon fiber or glass fiber. We aim to study effects of carbon fiber and glass fiber on thermal, mechanical, and shape memory properties of benzoxazine-epoxy SMPs, particularly on recovery stress enhancement. The compositions of carbon fiber and glass fiber reinforced benzoxazine-epoxy SMPs were in a range of 30 to 50vol%. The carbon fiber and glass fiber reinforced benzoxazine-epoxy shape memory polymer was compression-molded at 170oC under a pressure of 10 MPa …

Photocatalytic Degradation Of Methylene Blue Over Polydopamine-Ag/Tio2, Kamonthip Tammarakwattana

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigated the effect of silver and polydopamine (PDA) doping on TiO2 catalysts for the photocatalytic degradation of methylene blue in aqueous phase. Titanium dioxide was synthesized via a sol-gel method and was calcined at 400 °C for two hours. Silver was loaded onto TiO2 by an incipient wetness impregnation method. The amount of Ag was varied from 0.5%wt to 3%wt. Then polydopamine-Ag/TiO2 catalyst was prepared by an impregnation method, using dopamine as a precursor. The amounts of polydopamine were 5%wt and 10%wt. All catalysts were characterized by N2 physisorption, ICP-OES, XRD, FTIR, CO chemisorption, Photoluminescence, and UV-Visible spectrophotometry. …

Performance Comparison Of Different Membrane Micro-Channel Reactors For Methanol Production From Biogas And Hydrogen, Khunnawat Ountaksinkul

Chulalongkorn University Theses and Dissertations (Chula ETD)

In order to integrate simultaneous methanol production with biogas upgrading in a single unit, the computational fluid dynamics (CFD) models of a triple pipe tubular membrane reactor (TMR) and a planar membrane micro-structured reactor (MMR) were established via COMSOL Multiphysics 5.3a and compared their effect on reactor performance under predetermined condition. For the conceptual design of these reactors, the channel inside the reactors can be divided into three parts; biogas channel (BC), reaction channel (RC) and sweep gas channel (SC). The CO2 in biogas entering into BC is separated through CO2 selective membrane to produce methanol inside RC. Afterwards, water …

Computational Fluid Dynamic Study Of Sorption Enhanced Steam Reforming Of Methane/Ethanol In Circulating Fluidized Bed System, Kiattikhoon Phuakpunk

Chulalongkorn University Theses and Dissertations (Chula ETD)

Two-dimensional fluid dynamic models were used to optimize and design a proper pilot-scale system for sorption enhanced steam methane reforming (SESMR) and sorption enhanced steam reforming of ethanol (SESRE) in a circulating fluidized bed reactor (CFBR) using Ni-based catalyst and dolomite as sorbent. The CFBR system was separately designed as 3 parts: including a SESMR riser, a SESRE and a regenerator. The SESMR riser could get H2 purity reached equilibrium of 98.58% in dry basis with the highest H2 flux of 0.301 kg/m2s when operating with steam to carbon ratio of 4 mol/mol, gas velocity of 6 m/s, inlet temperature …

Synthesis Of Ptco/Tio2 Catalysts By Flame Spray Pyrolysis For Selectiive Hydrogenation Of Furfural To Furfuryl Alcohol, Kitima Kruachao

Chulalongkorn University Theses and Dissertations (Chula ETD)

The selective hydrogenation of furfural to furfuryl alcohol (FA) was carried out in a batch reactor at 50 ̊C and 20 bar H2 using Pt-Co/TiO2 with 0.5 wt%Pt and 0-0.8 wt%Co. The catalysts were characterized by X-ray diffraction (XRD), N2-physisorption, X-ray photoelectron spectroscopy (XPS), H2-temperature programmed reduction (H2-TPR), atomic absorption spectroscopy (AAS), CO-pulse chemisorption and transmission electron microscopy (TEM). Addition of Co into monometallic (I) Pt/TiO2 catalyst increased both furfural conversion and FA selectivity because it prevented anatase to rutile transformation of TiO2 and increased the interaction between metal and TiO2. However, Co adding into monometallic (F) Pt/TiO2 catalyst resulted …

Effects Of Polyol Molecular Weights On Thermally Reversible Light Scattering Behaviors Of Benzoxazine-Urethane Copolymers, Kittipon Bunyanuwat

Chulalongkorn University Theses and Dissertations (Chula ETD)

The thermally reversible light scattering behaviors of benzoxazine-urethane copolymer was investigated in this work. Benzoxazine monomers (BA-a) were synthesized by the solventless synthesis technique from bisphenol-A, para-formaldehyde, and aniline with the molar ratio of 1:4:2, respectively. Urethane prepolymer was prepared by reacting poly(propylene glycol) (Mw = 1000, 2000, or 3000 g/mol) with toluene diisocyanate (TDI) at the molar ratio of 1:2 under a nitrogen atmosphere. The obtained urethane prepolymer (PU) was labelled as PU1K, PU2K, and PU3K with respect to the molecular weights of polyether polyol employed in the preparation step. Urethane prepolymer and benzoxazine monomers were crosslinked during the …

Development Of High Performance Ballistic Armor From Varied Fiber Reinforced Polybenzoxazine Composites, Manunya Okhawilai

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this research, a hard ballistic armor based on fiber reinforced polybenzoxazine/polyurethane (PBA/PU) composite as human body armor was developed to protect the 7.62×51 mm projectile at a velocity of 847±9.1 m/s according to National Institute of Justice at test level III. The hard armor consisted of two main panels, i.e., strike panel to destroy the tip of projectile which was made from glass fiber reinforced PBA composite and absorption panel from aramid fiber reinforced PBA/PU composite to absorb impact energy. It was found that S glass composite exhibited a greater performance than E glass composite having the same number …

Nanocomposite Membranes Incorporated With Graphene Oxide For Co2/Ch4 Separation, Nadia Norahim

Chulalongkorn University Theses and Dissertations (Chula ETD)

Biogas is an alternative energy produced by anaerobic digestion of organic matter. Generally, raw biogas consists of methane (CH4), carbon dioxide (CO2), few amount of hydrogen sulfide (H2S) and traces of water vapor. Nowadays, upgrading raw biogas is required in order to achieve higher calorific value and meet fuel standard by removal of CO2. In this study, composite membranes of PEG 400/Pebax 1657 blended polymer with graphene oxide (GO) and amine functionalized graphene oxide (Fn-GO) were successfully developed for CO2/CH4 gas separation. The effects of graphene oxide, amine functionalized graphene oxide and PEG 400 additions on CO2/CH4 separation performance were …

Synthesis Of Cu2znsns4 For Thin Film Solar Cells Prepared By Solution-Based Processes, Napaporn Khothong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Copper zinc thin sulphide (Cu2ZnSnS4: CZTS) thin films were synthesized via convective deposition method at various deposit speeds based on sol-gel precursor of 2-methoxyethanol solution with metal chlorides and thiourea. The deposited films were annealed at 340 to 550ºC under N2 atmosphere to yield high quality CZTS films. The compositions, morphology, phase, and optical properties of the CZTS films were characterized by Energy dispersive X-ray analysis (EDX), Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and UV-Vis spectrophotometer, respectively. The formation films exhibited in kesterite structure and the band gap was about 1.4-1.5 eV. The CZTS films also applied …

Characteristics And Catalytic Properties Of Agli/Sio2 Catalysts On Different Silica Supports For Oxidative Dehydrogenation Of Ethanol To Acetaldehyde, Narawich Mukda

Chulalongkorn University Theses and Dissertations (Chula ETD)

This work focuses on investigation of the oxidative dehydrogenation and non-oxidative dehydrogenation of ethanol over AgLi/SiO2 catalysts to produce acetaldehyde by having three different types of silica support, spherical silica particle (small particle size; SPS), medium silica particle size (MPS), and large silica particle size (LPS). The spherical silica particle (SSP) was synthesized using the sol-gel method, whereas SiO2 (MPS) and SiO2 (LPS) were obtained from commercial suppliers. AgLi/SiO2 catalysts were prepared by incipient wetness co-impregnation method. The physicochemical properties of catalysts were analyzed by using several technique such as X-ray diffraction (XRD), N2-physisorption, SEM-EDX, UV-visible spectroscopy, H2-TPR. Moreover, the …

Effects Of Titanium Dioxide Structure And Cobalt Addition On The Catalytic Properties Of Ru/Tio2 In The Selective Hydrogenation Of Furfural To Furfuryl Alcohol, Natdanai Nanthasanti

Chulalongkorn University Theses and Dissertations (Chula ETD)

Furfuryl alcohol, an important intermediate for the production of many fine chemicals, is typically produced by the selective hydrogenation of lignocellulosic biomass-derived furfural using supported metal catalysts. In this research, 1.5%wt Ru catalysts supported on nanocrystalline TiO2 were prepared by incipient wetness impregnation method. The effects of crystallographic of TiO2 and Co addition in the range of 0.2-0.8 wt% on the catalytic properties of Ru/TiO2 were investigated in the selective hydrogenation of furfural to furfural alcohol at 50°C, 20 bar of H2, and 2 h reaction time. It was found that Ru supported on anatase phase TiO2 exhibited the highest …

Dehydration Of Ethanol Over Zsm-5 Catalysts Having Different Si/Al Molar Ratios With H3po4 And Pd Modification, Nattawat Nampipat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Dehydration of ethanol was studied over ZSM-5, HZSM-5 and modified HZSM-5 catalysts under atmospheric pressure and temperature range of 200 °C to 400 °C. ZSM-5 catalysts were prepared by hydrothermal method using tetraphopylammonium bromide, sodium silicate solution and aluminium nitrate nonahydrate. The results showed that the various Si/Al molar ratios led to affect the amount of acidity on the surface of catalysts. The ZSM-5(20) catalyst exhibited the highest ethanol conversion at 400 °C about 70.3 % due to its high acid sites and large surface area. The commercial HZSM-5 catalysts, which had molar ratio similar to ZSM-5 Si/Al 20 catalysts, …

Ethylene Polymerization Over Cellulose-Supported Modified Methylaluminoxane/Zirconocene Catalyst, Natthadabhorn Thanarattanasap

Chulalongkorn University Theses and Dissertations (Chula ETD)

Presently, the polyethylene has been profusely applied in the several industries, for instance manufacturing of pipe, film and plastic bags. In polyethylene production, there are two catalysts which are used in production, including Ziegler-Natta catalyst and metallocene catalyst. The metallocene catalyst is immobilized by support and activated by cocatalyst. For the support of metallocene catalysts, both of inorganic and organic supports are applied and in this research study, cellulose which is organic support for metallocene catalyst, was used. Since, cellulose is extensively used biopolymer representing a great deal of total annual biomass production. Due to environmental issues, natural materials have …

Effects Of Pbs Quantum Dot Doped Tio2 Nanotubes As Electron Transporting Layer On The Efficiency Of Perovskite Solar Cells, Natthapat Rattanawichai

Chulalongkorn University Theses and Dissertations (Chula ETD)

TiO2 nanotubes (TNTs) are used as an excellent electron transporting layer for high efficiency perovskite solar cells. In this work, TNTs were synthesized via hydrothermal process from different particle sizes of TiO2 nanoparticle precursors as follows: 5 nm, 25 nm, and 50 nm. The highest surface area of 312.39 m2/g of TNTs was obtained from TiO2 precursor with particle size of 25 nm and was used to dope with lead sulfide quantum dots (PbS QDs). Due to a large band gap and poor conductivity of TNTs which limits the efficiency to transport electrons in the perovskite solar cell, PbS QDs …