Galvanic And Pitting Corrosion Of A Fastener Assembly,
2018
The University of Akron
Galvanic And Pitting Corrosion Of A Fastener Assembly, Julie Shallman
Williams Honors College, Honors Research Projects
This research focuses on coupled galvanic/pitting corrosion of AA7075 when combined with stainless steel in a fastener assembly. A one-dimensional mathematical model of a well-mixed thin film electrolyte is developed to predict the damage profile of the AA7075 surface when its protective coating is damaged. The damage exposes the galvanic couple. A time dependent system of partial differential equations for potential, chloride concentration, aluminum ion concentration, and damage is developed and solved numerically. Two approaches to calculate the current density within aluminum pits are discussed. The first is a current balance between the cathodic, anodic and passive portions of the …
Investigation Of Combustion Characteristics Of A Heavy-Duty Diesel Engine Retrofitted To Natural Gas Spark Ignition Operation,
2018
West Virginia University
Investigation Of Combustion Characteristics Of A Heavy-Duty Diesel Engine Retrofitted To Natural Gas Spark Ignition Operation, Jinlong Liu
Graduate Theses, Dissertations, and Problem Reports (ETD)
The conversion of existing diesel engines to natural-gas spark ignition operation by adding a gas injector in the intake manifold for fuel delivery and replacing the diesel fuel injector with a spark plug to initiate and control the combustion process can reduce U.S. dependence on petroleum imports and curtail engine-out emissions. As the conventional diesel combustion chamber (i.e., flat head and bowl-in-piston) creates high turbulence, the engine can operate leaner, which would increase its efficiency and reduce emissions. However, natural gas combustion in such retrofitted engines presents differences compared to that in conventional spark ignited engines. Subsequently, the main goal …
Development Of Bimetallic Catalysts For Dry Reforming Of Methane And Hydrogenation Of Succinic Acid,
2018
University of South Carolina
Development Of Bimetallic Catalysts For Dry Reforming Of Methane And Hydrogenation Of Succinic Acid, Jayson Michael Keels
Theses and Dissertations
Advances in natural gas recovery have greatly impacted the global economy; the abundant supply of gas has revealed new opportunities and challenges in a wide range of markets within the fuels and chemicals industries. One such opportunity exists with the overabundance of gas from remote wells that is flared or emitted because of the high costs associated with transportation of a chemical with such a high molar volume. A possible solution is an on-site process to convert gas to higher value chemicals that are liquid at standard conditions, and can more easily be transported. As a first step, CO2 from …
Selective Deposition Of Platinum By Strong Electrostatic Adsorption Onto Cobalt- And Iron-Based Catalysts For Fischer-Tropsch Synthesis,
2018
University of South Carolina
Selective Deposition Of Platinum By Strong Electrostatic Adsorption Onto Cobalt- And Iron-Based Catalysts For Fischer-Tropsch Synthesis, Fahad A. Almalki
Theses and Dissertations
Cobalt and iron based catalysts are commercially predominant for Fischer-Tropsch synthesis, Co-based catalysts for their stability, activity, and inactivity for the water gas shift reaction and Fe-based catalysts for their cheap cost, high light-olefins and alcohols selectivity, and tolerance to H2/CO ratio. These catalysts are structure sensitive with lower activity at nanoparticle sizes smaller than 6-8 nm. Co-based catalysts exhibit high activity, low CH4 selectivity, and high C5+ selectivity, while Fe-based catalysts are more selective to low-molecular-weight hydrocarbons such as olefins and alcohols. The reducibility of cobalt and iron is another important factor which may be key for improving their …
Dynamic Simulation Of A Solar Powered Hybrid Sulfur Process For Hydrogen Production,
2018
University of South Carolina
Dynamic Simulation Of A Solar Powered Hybrid Sulfur Process For Hydrogen Production, Satwick Boddu
Theses and Dissertations
The Hybrid Sulfur process is a thermo-electrochemical cycle used to produce hydrogen from water. The process requires a high temperature energy source for H2SO4 decomposition with temperature reaching 800°C. This step is followed by SO2 - depolarized water electrolysis. Using solar energy as the high temperature energy source allows for efficient environmentally friendly production of hydrogen. This method is an alternative to traditional photovoltaic electrolysis for hydrogen production. Making the process economically competitive is a major challenge. Operating the process with changes in the availability of solar energy also increases process complexity. The dependence of the process on solar energy …
Nox Formation In Syngas/Air Combustion,
2018
University of South Carolina
Nox Formation In Syngas/Air Combustion, Nazli Asgari
Theses and Dissertations
Syngas is a reliable energy source derived from the gasification of coal and other solid fuels. The feedstock type and the production process of syngas can affect the composition of syngas. Gas turbines utilizing high hydrogen content (HHC) fuels like syngas for power generation applications need to meet stringent pollutant emission standards, particularly with respect to nitrogen oxides (NOx). For gas turbine conditions, reliable experimental data, especially at high-pressure, is necessary for both generating accurate NOx prediction models and improving reaction pathways regarding the NOx chemistry. In this study, NOx formation in post-flame gases of syngas combustion at different conditions …
Graphene As A Solid-State Ligand For Palladium Catalyzed Cross-Coupling Reactions,
2018
Virginia Commonwealth University
Graphene As A Solid-State Ligand For Palladium Catalyzed Cross-Coupling Reactions, Yuan Yang
Theses and Dissertations
Palladium-catalyzed carbon-carbon cross-coupling reactions have emerged a broadly useful, selective and widely applicable method to synthesize pharmaceutical active ingredients. As currently practiced in the pharmaceutical industry, homogeneous Pd catalysts are typically used in cross-coupling reactions. The rational development of heterogeneous catalysts for cross-coupling reactions is critical for overcoming the major drawbacks of homogeneous catalysis including difficulties in the separation, purification, and quality control process in drug production. In order to apply heterogeneous catalysis to flow reactors that may overcome this limitation, the catalyst must be strongly bound to a support, highly stable with respect to leaching, and highly active. While …
Ore Reserves Estimation Of The Nam Nga Coal Deposit, Lao Pdr, Using Geostatistical Method,
2018
Faculty of Engineering
Ore Reserves Estimation Of The Nam Nga Coal Deposit, Lao Pdr, Using Geostatistical Method, Tongvang Bliachongvang
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research study focuses on estimating the coal deposit quantity and qualities as CV and AC at Nam Nga coal deposit, Lao PDR using OK and SGS geostatistical methods. A total of 295 assays data from 51 exploration drill holes collected from LID Company were used. The results reveal that OK produces geological resource of 2.2 MT with an average CV of 3,733 kcal/kg and an average AC of 48.68 %. The mineable reserve computed from OK's ultimate pit design and pit adjustment are 0.55 MT. The OK method produces 9.32 MT of wastes, yielding a stripping ratio of 10.4:1. …
Green-House Gas Storage Through Enhanced Hydrate Formation,
2018
The Petroleum and Petrochemical College
Green-House Gas Storage Through Enhanced Hydrate Formation, Thiphakorn Absuwan
Chulalongkorn University Theses and Dissertations (Chula ETD)
The CO₂ hydrate formation in the presence of different tetrahydrofuran (THF), sodium dodecyl sulfate (SDS), and methyl ester sulfonate (MES) concentrations was investigated in terms of kinetics and thermodynamics. The formation experiment was conducted in the quiescent condition and close system at 3 MPa and 3 °C. The results showed that the CO₂ hydrates formed in the presence of 10 mol% THF, while it did not form with 5.56 mol% THF. The presence of SDS or MES did not promote the hydrate formation. However, the hydrates formed in the presence of a mixture of SDS or MES with 5.56 mol% …
Optimization Algorithm Study : Mixed Integer Linear Programming,
2018
The Petroleum and Petrochemical College
Optimization Algorithm Study : Mixed Integer Linear Programming, Tittawat Fongchantuk
Chulalongkorn University Theses and Dissertations (Chula ETD)
In the present, many petrochemical and petroleum products (engine fuel, solvent, plastic and synthetic rubber. etc.) are important. They are transported by ship, pipe line or train every day. So, minimizing transportation cost and time or maximizing profit is an important key of every company. In this optimization process, the optimal supply chain must be well developed in mathematical programming with the objective function of minimum cost or maximum profit and be solved by using optimization solvers. Objective functions and their constraints are solved by suitable types of optimization solvers: Linear programming (LP) and mixed integer linear programming (MILP). MILP …
Ethanol Dehydration With Oxygen Cofeeding Over Palladium Catalyst Supported On Spherical Silica Particle With Ceria Modification,
2018
Faculty of Engineering
Ethanol Dehydration With Oxygen Cofeeding Over Palladium Catalyst Supported On Spherical Silica Particle With Ceria Modification, Kanjanee Sinchai
Chulalongkorn University Theses and Dissertations (Chula ETD)
Ethanol dehydration with oxygen cofeeding over palladium catalyst supported on spherical silica particle with ceria modification was carried out in fixed bed reactor under atmospheric pressure and temperature range of 150 ˚C to 350 ˚C (O2/Ethanol molar ratio = 2.2). The results showed that the effect of ceria modification of Pd/CeO2/SSP catalyst exhibited higher activity than Pd/SSP and CeO2/SSP at 200 ˚C. Pd/CeO2/SSP catalyst yielded very the high ethanol conversion at 200 °C about 57.7 %. However, the preparation method with different sequence of loading has significant effects on crystallite size, surface area, H2-TPR profile and catalytic activity. Pd-CeO2/SSP was …
Dehydration Of Ethanol To Diethyl Ether Over Beta Zeolite Catalysts,
2018
Faculty of Engineering
Dehydration Of Ethanol To Diethyl Ether Over Beta Zeolite Catalysts, Montri Thapplee
Chulalongkorn University Theses and Dissertations (Chula ETD)
The catalytic ethanol dehydration to diethyl ether was investigated using synthesized beta zeolite catalysts having different Na and mixed Na-H form. The Na form in catalyst was synthesized by the hydrothermal process including non-calcined (Na-BEA_N) and calcined (Na-BEA_C) catalysts. The catalysts having different mixed Na-H forms were synthesized under ion-exchange method. In this study, two different cycles were chosen including one cycle (M-BEA_1) and four cycles (M-BEA_4). These catalysts were characterized by various techniques. The catalysts were tested to measure the catalytic activity at atmospheric pressure and the reaction temperature ranged from 150 to 400 °C. The results presented that …
Analysis And Design Of Vanadium Redox Flow Battery,
2018
Faculty of Engineering
Analysis And Design Of Vanadium Redox Flow Battery, Tossaporn Jirabovornwisut
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this study, the dynamic model of a vanadium redox flow battery (VRFB) was developed to analyze the battery performance and capacity degradation caused by an electrolyte imbalance from hydrogen and oxygen evolution and self-discharge side reactions. The model-based analysis of the VRFB performance revealed that the rate of battery capacity loss resulting from the electrolyte imbalance considerably depended on electrode and membrane material as well as operating conditions. Self-discharge reactions were controlled by the operational time of the battery. In addition, the rate of capacity degradation increased with an increase in the total vanadium concentration and operating temperature, affecting …
Designing Binary Low Ift Surfactant System Using Hld Concept For Oil Recovery,
2018
The Petroleum and Petrochemical College
Designing Binary Low Ift Surfactant System Using Hld Concept For Oil Recovery, Tukta Jamprakhon
Chulalongkorn University Theses and Dissertations (Chula ETD)
Surfactant-based microemulsion technology is widely used in tertiary enhanced oil recovery applications (EOR). The formulation of suitable surfactant system is a key success in production and economic feasibility of this technology. The middle phase or Winsor Type III microemulsions, employed for selecting appropriate surfactant system, can offer an optimal salinity at which the high oil solubilization capacity and minimum interfacial tension (IFT) or ultralow IFT (<0.01 mN/m) are obtained. By this technology, more remaining oil in the reservoir can be solubilized and mobilized which leads to an improvement of oil recovery. This study aims to formulate surfactant systems for the oil recovery through microemulsion formulation. The novel mixed anionic surfactant system of a sodium dioctyl sulfosuccinate (AOT) and an internal olefin sulfonates (IOS) with different alkyl chain lengths (C15-18, C19-23, C24-28) were used due to its mixture avoiding the surfactant precipitation. The result found that the binary mixture of AOT and (IOS C15-18 and IOS C19-23) can form the middle phase at the mixing ratios of 5:5 to 9:1 (by molar ratio) with heptane and decane. When the fraction of IOS increased in the mixed AOT/IOS system, the optimal salinity (S*) also increased. For the effects of a carbon tail length of IOS surfactant was observed that the tail length increased with decreasing the optimal salinity. The hydrophilic-lipophilic deviation (HLD) for the mixed surfactant system was investigated to individually determine the K and Cc values for the IOS surfactants. The finding from this work provided a guide for surfactant selection through HLD concept to formulate microemulsion-based surfactant flooding for EOR application.
Design Of Plantwide Control Structure Of Double Effect Water/Lithium Bromide Absorption Chiller,
2018
Faculty of Engineering
Design Of Plantwide Control Structure Of Double Effect Water/Lithium Bromide Absorption Chiller, Kris Prasopsanti
Chulalongkorn University Theses and Dissertations (Chula ETD)
Alternative control structures for a parallel double effect aqueous lithium bromide absorption chiller, operated in two modes of operation, has been designed using Skogastad's plantwide control procedure. In on-demand mode, two complete decentralized control structures with proportional integral (PI) controllers and one structure with a two inputs - two outputs model predictive controller (MPC) were proposed. Their performance was evaluated using MATLAB-Simulink dynamic simulation. The results varied depended on type of disturbance, but overall, the structure with MPC controller provided slightly better results with less liquid holdup changes and faster setting time in average. For on-supply mode, two self-optimizing control …
The Effects Of Tio2 Phase And Sio2 Supports On Methyl Oleate Epoxidation,
2018
Faculty of Engineering
The Effects Of Tio2 Phase And Sio2 Supports On Methyl Oleate Epoxidation, Nichaphat Sangkanchanavanich
Chulalongkorn University Theses and Dissertations (Chula ETD)
This work studies about the epoxidation reaction of methyl oleate with TiO2 or TiO2/SiO2 catalysts and hydrogen peroxide. Study of TiO2 catalysts interests in catalysts from commercial and sol gel method. The highest catalytic activity and selectivity of TiO2 from commercial is TiO2 commercial type B which gives 46.10% and 79.75%, respectively. For sol gel method, the highest catalytic activity at 75.82% and selectivity at 90.85% is TiO2 calcination temperature at 300OC, due to low crystallinity and high surface area. TiO2/SiO2 with different type of SiO2 support (MCM-41, SBA-15, silicalite, silica gel and fumed silica) shows different catalytic activity and …
Hydrogen Production From Sorption Enhanced Chemical Looping Steam Ethanol Reforming Using Calcium Oxide/ Copper Oxide/ Nickel Oxide Multifunctional Catalyst,
2018
Faculty of Engineering
Hydrogen Production From Sorption Enhanced Chemical Looping Steam Ethanol Reforming Using Calcium Oxide/ Copper Oxide/ Nickel Oxide Multifunctional Catalyst, Talita Nimmas
Chulalongkorn University Theses and Dissertations (Chula ETD)
Multifunctional catalyst was developed for hydrogen production via sorption enhanced chemical looping ethanol steam reforming. Calcium acetate (Ca2Ac) and calcium chloride (CaCl) were used as calcium precursor. Sodium carbonate (Na2CO3) and urea (CO(NH2)2) were used as carbonate precursor. The NiO/CaOAc-Urea-Ca12Al14O33 showed the longest pre-breakthrough period of 60 min and 88% of hydrogen purity at steam to ethanol molar ratio (S/E) of 4:1, temperature 600 ﹾC. Stability of NiO/CaOAc-Urea-Ca12Al14O33 was tested over 10 cycles and the results showed hydrogen purity can be maintained at 90% during pre-breakthrough period. The effect of synthesis method: sol-mixing and sol-gel, on hydrogen production was compared …
The Surface Modification Of Zeolite Y In Composite Selective Layer Of Hollow Fiber Membrane For Separation Of Co2/Ch4 Mixture,
2018
Faculty of Engineering
The Surface Modification Of Zeolite Y In Composite Selective Layer Of Hollow Fiber Membrane For Separation Of Co2/Ch4 Mixture, Thakorn Wichaidit
Chulalongkorn University Theses and Dissertations (Chula ETD)
This work focused on the fabrication and evaluation of composing hollow fiber mixed matrix membranes (MMMs) incorporated by zeolite Y for CO2/CH4 separation. The effects of surface modification of zeolite Y to improve compatibility of filler and polymer dispersibility of the filler in the polymer matrix on properties and separation performance of the membrane were investigated. A polysulfone (PSF) was used as a support hollow fiber and a selective layer composing of polyether-block-amide (Pebax) and zeolite Y (ZeY) and surface modification of zeolite Y (mo-ZeY) was coated on support. A [3-(2-Aminoethylamino)propyl]trimethoxysilane (AEAPTMS) was used to grafted on surface of pristine …
การพัฒนาฟิล์มบรรจุภัณฑ์บรรยากาศดัดแปรจากสารผสมระหว่างพอลิเอธิลีนชนิดความหนาแน่นต่ำกับเทอร์โมพลาสติกพอลิเอสเทอร์อีลาสโตเมอร์,
2018
คณะวิศวกรรมศาสตร์
การพัฒนาฟิล์มบรรจุภัณฑ์บรรยากาศดัดแปรจากสารผสมระหว่างพอลิเอธิลีนชนิดความหนาแน่นต่ำกับเทอร์โมพลาสติกพอลิเอสเทอร์อีลาสโตเมอร์, กันตพงศ์ สักลอ
Chulalongkorn University Theses and Dissertations (Chula ETD)
งานวิจัยนี้เป็นการพัฒนาฟิล์มบรรจุภัณฑ์บรรยากาศดัดแปร (Modified Atmosphere Packaging Film) โดยศึกษาถึงผลของปริมาณสารเทอร์โมพลาสติกพอลิเอสเทอร์อิลาสโตเมอร์ (TPEE) ในสัดส่วน 0 - 50% โดยน้ำหนักที่ถูกผสมเข้าไปในพอลิเอธิลีนชนิดความหนาแน่นต่ำ (LDPE) และสภาวะการขึ้นรูปฟิล์ม ได้แก่ อัตราเร็วในการดึงฟิล์ม (Film Pulling Speed) ช่วง 200 - 240 rpm และอุณหภูมิหล่อเย็นฟิล์ม 15 - 50 องศาเซลเซียสต่อค่าความสามารถในการซึมผ่านแก๊สและไอน้ำของฟิล์มที่ได้ ผลการทดลองพบว่าการเติม TPEE ลงใน LDPE ในปริมาณที่มากขึ้นส่งผลให้ความสามารถในการซึมผ่านไอน้ำและแก๊สของ MAP Film มีแนวโน้มเพิ่มขึ้น เพราะ TPEE มีความสามารถในการซึมผ่านไอน้ำและแก๊สสูงกว่า LDPE นอกจากนี้การเพิ่มอัตราเร็วในการดึงฟิล์มส่งผลทำให้ช่องว่าง (Void) บริเวณรอยต่อระหว่างวัฏภาคของ LDPE กับ TPEE กว้างขึ้น ส่งผลให้อัตราการซึมผ่านของไอน้ำและแก๊สเพิ่มขึ้นตามไปด้วย ในทางกลับกัน การเพิ่มอุณหภูมิหล่อเย็นฟิล์มส่งผลให้เปอร์เซ็นต์ความเป็นผลึกของฟิล์มเพิ่มขึ้น ทำให้อัตราการซึมผ่านของไอน้ำและแก๊สมีแนวโน้มลดลง ส่วนการทำนายเวลาที่แก๊สในถุงบรรจุภัณฑ์เข้าสู่สภาวะคงตัวและปริมาณแก๊สในถุงบรรจุภัณฑ์โดยใช้โปรแกรม MATLAB พบว่า ภายใต้สภาวะที่ศึกษา แก๊สในถุงบรรจุภัณฑ์เข้าสู่สภาวะคงตัวภายในเวลา 24 ชั่วโมง โดยที่ MAP Film ที่มีค่าความสามารถในการซึมผ่านแก๊สออกซิเจนสูงกว่า ทำให้ปริมาณแก๊สออกซิเจนภายในถุงบรรจุภัณฑ์ที่สภาวะคงตัวมีค่าสูงกว่าและในทางกลับกัน MAP Film ที่มีค่าความสามารถในการซึมผ่านแก๊สคาร์บอนไดออกไซด์สูงกว่า ทำให้แก๊สคาร์บอนไดออกไซด์ภายในถุงบรรจุภัณฑ์ที่สภาวะคงตัวมีค่าน้อยกว่า
Developing A 3d In Vitro Model By Microfluidics,
2018
CUNY City College
Developing A 3d In Vitro Model By Microfluidics, Hung-Ta Chien
Dissertations and Theses
In vitro tissue models play an important role in providing a platform that mimics the realistic tissue microenvironment for stimulating and characterizing the cellular behavior. In particular, the hydrogel-based 3D in vitro models allow the cells to grow and interact with their surroundings in all directions, thus better mimicking in vivo than their 2D counterparts. The objective of this thesis is to establish a 3D in vitro model that mimics the anatomical and functional complexity of the realistic cancer microenvironment for conveniently studying the transport coupling in porous tissue structures. We pack uniform-sized PEGDA-GelMA microgels in a microfluidic chip to …
